Structure-activity relationships and key structural feature of pyridyloxybenzene-acylsulfonamides as new, potent, and selective peroxisome proliferator-activated receptor (PPAR) γ Agonists

Article abstract of DOI:10.1016/j.bmc.2012.03.036

In our search for a novel class of non-TZD, non-carboxylic acid peroxisome proliferator-activated receptor (PPAR) γ agonists, we explored alternative lipophilic templates to replace benzylpyrazole core of the previously reported agonist 1. Introduction of a pentylsulfonamide group into arylpropionic acids derived from previous in-house PPARγ ligands succeeded in the identification of 2-pyridyloxybenzene-acylsulfonamide 2 as a lead compound. Docking studies of compound 2 suggested that a substituent para to the central benzene ring should be incorporated to effectively fill the Y-shaped cavity of the PPARγ ligand-binding domain (LBD). This strategy led to significant improvement of PPARγ activity. Further optimization to balance in vitro activity and metabolic stability allowed the discovery of the potent, selective and orally efficacious PPARγ agonist 8f. Structure-activity relationship study as well as detailed analysis of the binding mode of 8f to the PPARγ-LBD revealed the essential structural features of this series of ligands.

Full text of DOI:10.1016/j.bmc.2012.03.036

Bioorganic & Medicinal Chemistry 20 (2012) 3332–3358
Contents lists available at SciVerse ScienceDirect
Bioorganic & Medicinal Chemistry
journal homepage: www.elsevier.com/locate/bmc
Structure–activity relationships and key structural feature
of pyridyloxybenzene-acylsulfonamides as new, potent, and selective
peroxisome proliferator-activated receptor (PPAR)
c Agonists
Kentaro Rikimaru a, , Takeshi Wakabayashi a, , Hidenori Abe a, , Taisuke Tawaraishi a, , Hiroshi Imoto a,
,
⇑
,
Jinichi Yonemori a, , Hideki Hirose a, , Katsuhito Murase b, Takanori Matsuo a,à, Mitsuharu Matsumoto a,à
,
Chisako Nomura a,à, Hiroko Tsuge a,à, Naoto Arimura a,à, Kazutoshi Kawakami a,§, Junichi Sakamoto a,§
Miyuki Funami a,§, Clifford D. Mol c, Gyorgy P. Snell c, Kenneth A. Bragstad c, Bi-Ching Sang c,
,
Douglas R. Dougan c, Toshimasa Tanaka a,§, Nozomi Katayama a,à, Yoshiaki Horiguchi a, ,k, Yu Momose a,–
a Pharmaceutical Research Division, Takeda Pharmaceutical Company, Ltd, 17-85, Jusohonmachi 2-chome, Yodogawa-ku, Osaka 532-8686, Japan
b Takeda Pharmaceuticals International, Inc., One Takeda Parkway, Deerfield, 60015 IL, USA
c Takeda San Diego, Inc., 10410 Science Center Drive, San Diego, 92121 CA, USA
a r t i c l e i n f o
a b s t r a c t
Article history:
In our search for a novel class of non-TZD, non-carboxylic acid peroxisome proliferator-activated receptor
(PPAR) agonists, we explored alternative lipophilic templates to replace benzylpyrazole core of the pre-
viously reported agonist 1. Introduction of a pentylsulfonamide group into arylpropionic acids derived
from previous in-house PPAR ligands succeeded in the identification of 2-pyridyloxybenzene-acylsulf-
onamide 2 as a lead compound. Docking studies of compound 2 suggested that a substituent para to
the central benzene ring should be incorporated to effectively fill the Y-shaped cavity of the PPAR
ligand-binding domain (LBD). This strategy led to significant improvement of PPAR activity. Further
optimization to balance in vitro activity and metabolic stability allowed the discovery of the potent,
selective and orally efficacious PPAR agonist 8f. Structure-activity relationship study as well as detailed
Received 25 December 2011
Revised 13 March 2012
Accepted 14 March 2012
Available online 23 March 2012
c
c
c
Keywords:
PPARc agonists
Diabetes mellitus
SBDD
Acylsulfonamide
Isosteric replacement
c
c
analysis of the binding mode of 8f to the PPAR
c
-LBD revealed the essential structural features of this ser-
ies of ligands.
Ó 2012 Elsevier Ltd. All rights reserved.
1. Introduction
issue worldwide, and this trend will continue to increase in the
future reaching 380 million cases by the year 2025.2
Type 2 diabetes mellitus (T2DM), which accounts for more than
90% of the diabetic patients, is a chronic multifactorial metabolic
disease characterized by insulin resistance, hyperglycemia, and im-
paired insulin secretion. In the long term, metabolic perturbations,
including compensatory hyperinsulinemia appear to contribute to
the development of many other disorders such as dyslipidemia,
hypertension, and coronary heart disease. The combination of
these risk factors associated with a sedentary lifestyle and obesity
significantly increases morbidity and mortality.1 T2DM has rapidly
reached epidemic proportions becoming a major public health
In an era marked by the increasing prevalence of T2DM, one
class of new therapeutic agents, thiazolidinediones (TZDs) repre-
sented by pioglitazone and rosiglitazone, has emerged as ‘insulin
sensitizers’. TZDs were originally identified and optimized through
empirical in vivo screening in rodent diabetes models without
knowledge of the target protein. In 1995, scientists from
GlaxoSmithKline reported that TZDs are high affinity ligands for
the nuclear receptor, peroxisome proliferator-activated receptor
c
(PPAR
area of antidiabetic drug discovery and development.4–9 TZDs bind
and activate PPAR that functions as an essential transcriptional
regulator of glucose and lipid homeostasis. Among the 3 PPAR sub-
types, namely designated as PPAR , PPAR , and PPARd, PPAR is
the most extensively investigated. PPAR is predominantly ex-
c
),3 and these findings inspired extensive research in the
c
⇑
a
c
c
c
Corresponding author. Tel.: +81 6 6300 6063; fax: +81 6 6300 6306.
Medicinal Chemistry Research Laboratories.
Pharmacology Research Laboratories.
Discovery Research Center.
Strategic Planning Department.
à
pressed in adipose tissue and regulates the expression of a constel-
lation of genes closely related to adipocyte differentiation, glucose
and lipid metabolism, insulin sensitivity, inflammatory responses,
and cell proliferation.3,10
§
–
k
Present address: Umicore Precious Metals Japan Company, Ltd., 2-3, Kitaaoyama
1-chome, Minato-ku, Tokyo 107-0061, Japan.
0968-0896/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.bmc.2012.03.036

K. Rikimaru et al. / Bioorg. Med. Chem. 20 (2012) 3332–3358
3333
To date, a majority of PPARc ligands possessing a carboxylic
acid or its heterocyclic bioisostere such as TZD, oxazolidinone,
and tetrazole have been reported,11 whereas acyclic isosteres have
drawn little attention with only a few reports so far. In our search
for a new class of non-TZD and non-carboxylic acid PPAR
c
agonists, we recently identified a series of potent, selective, and
orally-active benzylpyrazole acylsulfonamides, represented by
compound 1, utilizing structure-based drug design (SBDD)
(Fig. 1).12 The co-crystal structure of 1 bound to the PPAR
c-li-
gand-binding domain (LBD) revealed that the acylsulfonamide
moiety interacts with Try327, His449 and/or Gln286 in the LBD
and may contribute to high PPAR
These findings encouraged us to investigate further acylsulfona-
mide-based PPAR ligands.
c selectivity over PPARa and d.
c
Despite showing an attractive profile, the benzylpyrazole-acyl-
sulfonamide 1 was found to have some disadvantages such as cyto-
toxicity, which is attributed to the high lipophilicity (clogP = 5.00,
clogD [pH 7.4] = 3.06).13 To address the liability, we set out to
identify an alternative and less hydrophobic template in place of
benzylpyrazole moiety. The structure–activity relationship (SAR)
of benzylpyrazole-acylsulfonamides indicates that an acylsulfona-
mide group connected via two carbon spacer is one of the key
Figure 2. Superposition of the docking model of compound 2 (shown in white)
bound to the PPARc-LBD [PDB code: 1PRG] and the co-crystal structure of
compound 1 (shown in blue). The binding space accommodating the isopropoxy
group of 1 is marked by a yellow circle.
structural elements for PPAR
several arylpropionic acids derived from previously identified in-
house PPAR ligands. An attempt to incorporate a pentylsulfona-
mide group into the arylpropionic acids gave a successful result,
leading to the identification of pyridyloxybenzene-acylsulfona-
mide 2 as a novel lead compound (Fig. 1). Indeed, the pyridyloxy-
benzene 2 (clogP = 4.59, clogD [pH7.4] = 2.66)13 is slightly less
hydrophobic than the benzylpyrazole 1. Overall, compound 2
was considered to be a promising starting point because of the
c activity. Therefore, we focused on
ring and the terminal side chain were generally synthesized by the
route outlined in Scheme 1. The 4-hydroxy group of commercially
available dihydroxybenzaldehyde (3) was selectively protected as
methoxymethyl (MOM) ether to give 4a. Compound 4a and com-
mercially available 4b were reacted with 2-chloropyridine to pro-
vide the pyridyloxybenzaldehydes 5a,b, which were subjected to a
Horner–Wadsworth–Emmons homologation to afford the cinna-
mate esters 6a–c. Incorporation of various alkyl moieties into the
4-hydroxy group of the central benzene core of 6a,c was carried
out by deprotection of the MOM group, followed by O-alkylation
or Mitsunobu reaction14 with appropriate alcohols to yield
7d,e,g–m. The double bond of 7e was reduced by catalytic hydro-
genation to produce 7f. As for the preparation of 7a,c, the double
bond was hydrogenated prior to the MOM-deprotection and O-
alkylation sequence. The esters 7a–m were then converted to the
target acylsulfonamides 2,8a–l,n,p,q acylsulfamide 8r by alkaline
hydrolysis and subsequent condensation with various sulfona-
mides or sulfamide utilizing carbonyl diimidazole (CDI), water-sol-
uble carbodiimide (WSC), or thionyl chloride as a coupling reagent.
The 2-hydroxyethoxy and 3-oxobutoxy derivatives 8m,o were
lastly obtained by deprotection of triisopropyl (TIPS) group of 8l
or dioxolane of 8n under standard conditions.
Modification of the 2-pyridyloxy group or linker moiety of 8f
was performed by the procedure shown in Scheme 2. Mitsunobu
reaction of compound 3 with 2-methoxyethanol proceeded mainly
at the 4-hydroxy group to furnish the desired regioisomer 9.
Conversion of 9 to the target compounds 13a–d,g was achieved
by the following 2 synthetic routes. The first is analogous to that
described in Scheme 1. Installation of substituted pyridyl groups
into 9 provided the pyridyloxybenzene congeners 11a,b. Com-
pound 11a was then subjected to a Horner–Wadsworth–Emmons
c
moderate PPARc potency as well as high subtype selectivity.
To support our optimization strategy, we performed a molecu-
lar docking study of 2 using the GOLD program (ver. 2.0, the Cam-
bridge crystallographic date centre, UK). Compound 2 was docked
to the 3-dimensional protein structure derived from the co-crystal
structure of PPAR
was superposed with the complex of 1 (Fig. 2). Compound 2 was
estimated to be bound to the PPAR -LBD in a similar fashion to
c
-LBD with compound 112 and the docking model
c
that of compound 1. It can be seen that there is a space around
the 4 position of the benzene ring of 2, into which the isopropoxy
group of 1 extends. Therefore, we reasoned that incorporation of a
suitable substituent into this position could further improve the
potency.
In this article, we wish to report the synthesis, SAR, in vitro and
in vivo biological profiles of pyridyloxybenzene-acylsulfonamides.
Furthermore, on the basis of X-ray co-crystallographic studies, the
key pharmacophores and structural requirements for PPAR
c bind-
ing are also discussed.
2. Chemistry
The pyridyloxybenzene-acylsulfonamides 2,8a–l,n,p,q and -
acylsulfamide 8r possessing various alkoxy groups on the benzene
F3C
Cl
N
F3C
Cl
O
O
N
O
O
O
O O
2
S
S
3
4
N
N
Me
N
Me
H
H
i-PrO
1: PPARγ/α/δ EC50 = 10 / >10000 / >10000 nM
Figure 1. Benzylpyrazole- and pyridyloxybenzene-based acylsulfonamide PPAR
2: PPARγ/α/δ EC50 = 61 / >10000 / >10000 nM
agonists 1 and 2.
c

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K. Rikimaru et al. / Bioorg. Med. Chem. 20 (2012) 3332–3358
F3C
Cl
O
F3C
Cl
O
O
O
OH
OH
a
b
c
N
N
O
H
H
CO2Et
H
HO
R1
R2
R1
R1
3
4a [R1 = MOMO-]
4b [R1 = H]
6a [R1 = MOMO-, R2 = H]
5a [R1 = MOMO-]
5b [R1 = H]
6b [R1,R2 = H]
1
[R = MOMO-, R2 = Me]
6c
d
or
F3C
F3C
Cl
O
Cl
O
d,e,g
or
h,i
f,g
O
N
N
O
O
CO2Et
S
N
R3
H
R2
R2
R1
R1
7a [R1 = MeO(CH2)2O-, R2 = H, bond = single]
8a [R1 = MeO(CH2)2O-, R2 = H, bond=single, R3 = pentyl]
3
1
2
1
[R ,R = H, bond = single]
[R ,R2 = H, bond = single, R = pentyl]
7b
7c
7d
7e
2
3
[R1 = Et2NC(=O)CH2O-, R2 = H, bond = single]
[R1 = MeO(CH2)2O-, R2 = H, bond = double]
[R1 = MeO(CH2)2O-, R2 = Me, bond = double]
[R = Et2NC(=O)CH2O-, R2 = H, bond = single, R = pentyl]
1
8b
8c
8d
[R1 = MeO(CH2)2O-, R2 = H, bond = single, R3 = -(CH2)3OMe]
[R = MeO(CH2)2O-, R2 = H, bond = single, R3 = Ph]
1
d
7f [R1 = MeO(CH2)2O-, R2 = Me, bond = single]
7g [R1 = i-PrO-, R2 = H, bond = double]
8e [R1 = MeO(CH2)2O-, R2 = H, bond = single, R3 = (4-Cl)Ph]
8f [R1 = MeO(CH2)2O-, R2 = H, bond = double, R3 = pentyl]
8g [R1 = MeO(CH2)2O-, R2 = Me, bond = double, R3 = pentyl]
7h [R1 = c-PrO(CH2)2O-, R2 = H, bond = double]
7i [R1 = MeO(CH2)3O-, R2 = H, bond = double]
8h [R1 = MeO(CH2)2O-, R2 = Me, bond = single, R3 = pentyl]
3
[R1 = TIPSO(CH2)2O-, R2 = H, bond = double]
[R1 = i-PrO-, R2 = H, bond = double, R = pentyl]
7j
8i
1
, R2 = H, bond = double]
8j [R1 = c-PrO(CH2)2O-, R2 = H, bond = double, R3 = pentyl]
7k
[R
=
O
O
3
[R1 = MeO(CH2)3O-, R2 = H, bond = double, R = pentyl]
8k
8l
8m
8n
O
3
[R1 = TIPSO(CH2)2O-, R2 = H, bond = double, R = pentyl]
j
7l [R1 = MeSO2(CH2)3O-, R2 = H, bond = double]
7m [R1 = NC(CH2)3O-, R2 = H, bond = double]
[R1 = HO(CH2)2O-, R2 = H, bond = double, R3 = pentyl]
1
[R
=
, R2 = H, bond = double, R3 = pentyl]
O
O
O
k
8o [R1 = MeC(=O)(CH2)2O-, R2 = H, bond = double, R3 = pentyl]
8p [R1 = MeSO2(CH2)3O-, R2 = H, bond = double, R3 = pentyl]
3
[R1 = NC(CH2)3O-, R2 = H, bond = double, R = pentyl]
8q
8r
[R1 = MeO(CH2)2O-, R2 = H, bond = single, R3 = NH(pentyl)]
Scheme 1. Reagents and conditions: (a) MOMCl, K2CO3, acetone, rt; (b) 2,3-dichloro-5-(trifluoromethyl)pyridine, NaH, DMF, rt?50 °C; (c) (EtO)2P(@O)CHR2CO2Et, NaH, THF,
DMF, 0 °C?rt; (d) H2, Pd/C, THF, rt; (e) conc. HCl, THF, 50 °C; (f) 1 M HCl, acetone, reflux; (g) alcohol, ADDP, tributylphosphine, THF, 50 °C, 12–95%, for 7a,d,e,h,j; alkyl halide
or alkyl tosylate, K2CO3, DMF, rt–80 °C, for 7c,g,i,k–m; (h) 1 M NaOH, THF, EtOH, 50 °C; (i) CDI, THF, reflux, then sulfonamide, DBU, rt, for 2,8a–d,i; sulfonamide or sulfamide,
WSC-HCl, DMAP, with or without TEA, MeCN, for 8f–h,j–l,n,p–r; SOCl2, THF, 0 °C then 4-chlorobenzenesulfonamide, DIPEA, DMAP, THF, rt, for 8e; (j) TBAF, THF, rt; (k) 1 M
HCl, THF, 60 °C.
reaction to give compound 12c. In the second route, a Wittig-elon-
gation of 9 is performed prior to installation of aryl group. Treat-
bond of the pyridyl ether to predominantly afford b-(2-hydroxyl-
phenyl)pivalic acid. By contrast, acidic hydrolysis of 15 worked
well, and the resulting carboxylic acid was subsequently coupled
with pentane-1-sulfonamide to generate acylsulfonamide, which
was treated with one equivalent of sodium hydroxide to afford
the corresponding sodium salt 16. Finally, benzyl alcohol 14 was
coupled with pentane-1-sulfonamide using CDI to afford sulfonyl
carbamate 17.
Incorporation of the pyridyloxy group into the central ben-
zene core at a later stage to prepare compounds 23a–d possess-
ing a single bond linker was performed as shown in Scheme 3.
Selective and successive alkylation of the two hydroxyl groups
ment of
9 with carboethoxymethylenetriphenylphosphorane
afforded 2-hydroxycinnamic acid ester 10, which was converted
to the aryloxybenzene derivatives 12a,b,d,e. The nitro group of
12e was reduced by zinc powder-acetic acid to furnish aniline
12f, which was subsequently reacted with di-tert-butyl dicarbon-
ate (Boc2O) to yield Boc-protected aniline 12g. Compounds
12a–d,g were subjected to saponification and subsequent conden-
sation with pentane-1-sulfonamide, using 2-methyl-6-nitroben-
zoic anhydride (MNBA)15 as
a coupling agent in place of
WSC-HCl, to generate 13a–e. The Boc group of 13e was removed
by the treatment of hydrochloric acid in MeOH to furnish aniline
13f, which was acetylated to yield acetanilide 13g. In parallel,
reduction of 11b using sodium borohydride produced benzyl
alcohol 14. Acetylation of the alcohol of 14 followed by a Lewis
acid-mediated SN1 reaction of benzylic cation, generated from
acetate ester of 14, with silylketene acetal proceeded smoothly to
give the b-phenylpivalic acid ester 15 in high yield.16 Standard
basic hydrolysis of the ester 15 accompanied cleavage of the C–O
of compound
which were then subjected to a Horner–Wadsworth–Emmons
reaction or aldol condensation with -substituted acetate to give
3 produced 2-benzyloxybenzaldehydes 19a–c,
a
the cinnamic acid esters 20a–c. Deprotection of the MOM group
of 20c and subsequent alkylation under Mitsunobu reaction con-
ditions afforded 20e. Saturation of the double bond and simulta-
neous removal of the benzyl group of 20a,b,e were achieved by
catalytic hydrogenation to provide the
a-substituted propionic

K. Rikimaru et al. / Bioorg. Med. Chem. 20 (2012) 3332–3358
3335
O
O
OH
OH
OH
a
b
CO2Et
H
H
MeO
MeO
HO
O
O
3
9
10
c
c
R
R
R
d
g,h
N
O
O
O
O
X
O
X
O
O
O
CO2Et
S
H
N
Pentyl
H
MeO
MeO
MeO
O
O
12a [X = CH, R = 2-Cl, 4-CF3]
12b
13a [X = CH, R = 3-Cl, 5-CF3, bond = double]
13b
11a (R = 3-Cl)
[X = N, R = 5-CF3]
12c [X = N, R = 3-Cl]
12d
[X = N, R = 5-CF3, bond = double]
13c [X = N, R = 3-Cl, bond = double]
13d
11b
(R = 3-Cl, 5-CF3)
[X = N, R = 3,5-diCl]
12e [X = N, R = 3-Me, 5-NO2]
12f
[X = N, R = 3,5-diCl, bond = double]
13e [X = NH, R = 3-Me, 5-NHBoc, bond = double]
13f
e
f
i
[X = N, R = 3-Me, 5-NH2]
12g [X = N, R = 3-Me, 5-NHBoc]
[X = NH, R = 3-Me, 5-NH2, bond = double]
13g [X = NH, R = 3-Me, 5-NHAc, bond = double]
k
j
F3C
Cl
F3C
F3C
Cl
O
Cl
O
N
O
O
l,m
n,h,o
O
N
O
N
O
O
O
CO2Me
Me Me
S
OH
N-
Pentyl
MeO
Na+
Me Me
MeO
MeO
14
15
16
F3C
Cl
p
O
N
O
O
O
S
N
Pentyl
O
H
MeO
O
17
Scheme 2. Reagents and conditions: (a) 2-methoxyethanol, DEAD, triphenylphosphine, THF, 0 °C?rt; (b) Ph3P@CHCO2Et, DCM, 0 °C?rt; (c) appropriately substituted 2-
chloropyridine or 3-chloro-4-fluorobenzotrifluoride, K2CO3 or NaH DMF, 50–120 °C, for 11a,b,12a,b,d,e; (d) (EtO)2P(@O)CH2CO2Et, NaH, THF, 0 °C, for 12c; (e) Zn, AcOH, H2O,
rt; (f) Boc2O, THF, reflux; (g) 1 M NaOH, THF, EtOH, 50–60 °C; (h) pentane-1-sulfonamide, WSC-HCl or MNBA, DMAP, with or without TEA, MeCN or DMF, rt, for 13a–e; CDI,
THF, reflux, then pentane-1-sulfonamide, DBU, rt, for 16; (i) 10% HCl in MeOH, 45 °C; (j) Ac2O, DMAP, pyridine, rt; (k) NaBH4, THF, MeOH, 0 °C; (l) Ac2O, pyridine, rt; (m) 1-
methoxy-2-methyl-1-(trimethylsiloxy)propene, Mg(ClO4)2, toluene, 50 °C; (n) conc. H2SO4, AcOH, THF, H2O, 80 °C; (o) 1 M NaOH, MeOH; (p) CDI, DMF, 40 °C, then pentane-1-
sulfonamide, DBU, DMAP, rt.
acid esters 21a–c. Introduction of the pyridyl group into 21a–c
and final construction of acylsulfonamide or amide moiety affor-
ded the target compounds 23a–d.
3. Results and discussion
3.1. In vitro structure–activity relationships
Replacement of the vinylene linker of 8f with cyclopropane
was carried out by the procedure shown in Scheme 4. The
MOM-protected cinnamic acid ester 24, which was easily prepared
from 10, was subjected to a Corey-Chaykovsky cyclopropanation to
successfully give 25 despite low yield.17 The following conversion
scheme was conducted by a similar procedure to that depicted in
Scheme 3 to afford the desired compound 27.
The newly synthesized compounds in this study were evaluated
for their ability to activate human PPAR subtypes
metabolic stability in human microsomes. Stably transfected
CHO-K1 cells were used in PPAR transactivation assay, and tran-
siently transfected COS-1 cells were used in PPAR and d transacti-
c, a, d and their
c
a
vation assays. The results are summarized in Tables 1–6, where the
Replacement of the acylsulfonamide group of 8a with various
functional groups was carried out by the procedure shown in
Scheme 5. The propionic acid ester 7b was subjected to dii-
sobutylalminium hydride (DIBAL-H) reduction to provide propanol
28. The alcohol of 28 was coupled with butylamine using CDI or
with pentane-1-sulfonamide using triphosgene to afford carba-
mate 29a and sulfonyl carbamate 29b, respectively. On the other
hand, the primary alcohol of 28 was converted to the correspond-
ing amine under Gabriel method conditions and subsequent acyla-
tion with sulfonyl chloride or chloroformate to give sulfonamide
32a and carbamate 32b, respectively.
activities are reported as half maximal effective concentration
(EC50) values. We used the agonists of PPAR
{4-[(2-furan-2-yl-5-methyl-1,3-oxazol-4-yl)-methoxy]-3-methoxy
phenyl}propyl)-1,3-oxazolidine-2,4-dione,18
({3-[(5-methyl-2-
acid,19
c, a, and d, (R)-5-(3-
phenyl-1,3-oxazol-4-yl)methoxy]benzyl}sulfanyl)acetic
and carbacyclin,20 respectively as reference compounds. To assess
metabolic stability, metabolic clearance was measured by the treat-
ment of test compounds with human or rat liver microsomes (see
Section 5).
Based on the above-mentioned docking study shown in Figure
2, we initially investigated incorporation of an alkoxy group into

3336
K. Rikimaru et al. / Bioorg. Med. Chem. 20 (2012) 3332–3358
OH
O
OH
O
BnO
O
BnO
CO2R3
a
b
c
H
H
H
R2
R1
HO
R1
R1
3
18a [R1 = i-PrO]
19a [R1 = i-PrO]
20a [R1 = i-PrO, R2 = H, R3 = Et]
20b [R1 = MeO(CH2)2O-, R2 = OMe, R3 = Me]
20c [R1 = MOMO, R2 = H, R3 = Et]
20d [R1 = HO, R2 = H, R3 = Et]
9 [R1 = MeO(CH2)2O]
4a [R1 = MOMO]
19b [R1 = MeO(CH2)2O]
19c [R1 = MOMO]
d
e
O
1
20e
[R
=
, R2 = H, R3 = Et]
N
O
F3C
Cl
F3C
Cl
OH
h,i
CO2R3
f
g
N
O
N
O
O
R3
N
CO2R3
R2
R1
H
R2
R2
R1
R1
21a [R1 = i-PrO, R2 = H, R3 = Et]
22a [R1 = i-PrO, R2 = H, R3 = Et]
23a [R1 = i-PrO, R2 = H, R3 = SO2(pentyl)]
21b [R1 = MeO(CH2)2O-, R2 = OMe, R3 = Me] 22b [R1 = MeO(CH2)2O-, R2 = OMe, R3 = Me] 23b [R1 = i-PrO, R2 = H, R3 = pentyl]
O
O
23c [R1 = MeO(CH2)2O-, R2 = OMe, R3 = SO2(pentyl)]
21c [R1
=
, R2 = H, R3 = Et]
22c [R1
=
, R2 = H, R3 = Et]
O
N
N
[R
=
, R2 = H, R3 = SO2(pentyl)]
O
O
1
23d
N
O
Scheme 3. Reagents and conditions: (a) 2-iodopropane, DIPEA, THF, rt, for 18a; 2-methoxyethanol, DEAD, triphenylphosphine, THF, 0 °C?rt, for 9; MOMCl, K2CO3, acetone, rt,
for 4a; (b) benzyl bromide, K2CO3, DMF, rt; (c) (EtO)2P(@O)CH2CO2Et, NaH, THF, 0 °C, for 20a,c; methyl methoxyacetate, KOt-Bu, THF, for 20b; (d) conc. HCl, THF, 40 °C; (e) 1-
(2-hydroxyethyl)-2-pyrrolidone, DEAD, TPP, THF, rt; (f) H2, Pd/C, THF, EtOH, rt, 88%-quant., for 21a,c; H2, Pd/C, MeOH, rt, for 21b (g) 2,3-dichloro-5-(trifluoromethyl)pyridine,
NaH, DMF, 0 °C; (h) 1 M NaOH, THF, EtOH or MeOH, rt–50 °C; (i) CDI, THF, reflux, then pentane-1-sulfonamide, DBU, rt, for 23a,d; SOCl2, cat. DMF, THF, 0 °C then pentylamine,
DIPEA, DMAP, THF, rt, for 23b; pentane-1-sulfonamide, WSC-HCl, DMAP, MeCN, rt, for 23c.
F3C
Cl
O
R
O
OMOM
b
c,d
CO2Et
CO2Et
N
O
CO2Et
MeO
MeO
O
O
MeO
10: R = H
24: R = MOM
25
a
26
F3C
Cl
O
e,f
N
O
O
O
S
N
Pentyl
H
MeO
O
27
Scheme 4. Reagents and conditions: (a) MOM-Cl, K2CO3, MeCN, rt; (b) trimethylsulfoxonium iodide, NaH, DMSO, 0 °C?rt; (c) 1 M HCl, acetone, 50 °C; (d) 2,3-dichloro-5-
(trifluoromethyl)pyridine, K2CO3, DMF, rt; (e) 1 M NaOH, THF, EtOH, rt; (f) pentane-1-sulfonamide, WSC-HCl, DMAP, MeCN.
the 4-position of the central benzene ring of compound 2 and the
results are shown in Table 1. The lead compound 2 lacking in a sub-
stituent at this position showed moderate PPARc agonism with an
(8a), amide (8b and 23d) were well tolerated, exhibiting single-di-
git nanomolar potency, but the metabolic stability of these
compounds was not improved.
EC50 value of 61 nM but suffered relatively high metabolic clear-
ance. In the previous report, a good correlation among in vitro met-
abolic clearance, in vivo plasma exposure and in vivo antidiabetic
efficacy was observed.12 Therefore, we first aimed at improving
Next, modification of the terminal side chain on the sulfonyl
group, maintaining the 2-methoxyethoxy group as the para substi-
tuent of the central benzene ring, was investigated and the repre-
sentative results are shown in Table 2. In the previously-identified
benzylpyrazole-acylsulfonamide series, the pentyl group was
shown to be the optimal among linear alkyl groups. Thus, we
examined substituents other than alkyl groups. Replacement of
the 4th methylene carbon of the pentyl group of 8a with an oxygen
atom (8c) greatly enhanced metabolic stability while showing low
double-digit nanomolar potency. However, the improvement in
metabolic stability was not reflected in in vivo pharmacokinetic
profile and efficacy of 8c (data not shown). The reason for the
discrepancy remains unclear. Substitution of the pentyl group of
PPAR
previous report, we set a goal of in vitro profiless to be EC50
<10 nM and metabolic clearance <50 L/min/mg. As we had
expected, incorporation of an alkoxy substituent (8a,b,23a and
23d) into the 4-position significantly improved PPAR activity
c activity as well as metabolic clearance. According to the
l
c
compared with 2. Isopropoxy analog 23a was about 23-fold more
potent than 2; however, in terms of metabolic stability, introduc-
tion of the isopropoxy group produced little if any improvement.
Thus, more polar alkoxy groups were briefly investigated. Ether

K. Rikimaru et al. / Bioorg. Med. Chem. 20 (2012) 3332–3358
3337
F3C
F3C
F3C
Cl
O
Cl
O
Cl
O
N
O
N
O
N
O
b or c
a
CO2Et
R
OH
O
MeO
MeO
MeO
7b
28
29a [R = CONHBu]
29b [R = CONHSO2(pentyl)]
d
F3C
F3C
F3C
Cl
O
Cl
O
Cl
O
e
f
N
O
N
O
N
O
O
R
N
NH2
N
H
MeO
MeO
MeO
O
30
31
32a [R = SO2(pentyl)]
32b [R = CO2Bu]
Scheme 5. Reagents and conditions: (a) DIBAL-H, THF, 0 °C; (b) CDI, DMF, 60 °C, then butylamine, rt, for 29a; (c) 1) triphosgene, pyridine, DCM, 0 °C; 2) pentane-1-
sulfonamide, DIPEA, DMAP, THF, rt, for 29b; (d) 1) MsCl, TEA, EtOAc, rt; 2) potassium phthalimide, DMF, 80 °C; (e) H2NNH2ꢀH2O, MeOH, 50 °C; (f) pentane-1-sulfonyl chloride
or butyl chloroformate, pyridine, EtOAc, rt.
Table 1
In vitro transactivation activity and metabolic stability of compounds 2,8a,b,23a and 23d
F3C
Cl
N
R
O
O
O
O
S
N
Me
H
Compound
R
PPAR
EC50 (nM)
c
transactivation
Metabolic clearanceb h/r (
lL/min/mg)
a
2
H
i-PrO
MeO(CH2)2O–
Et2NC(@O)CH2O–
61
78/120
57/94
77/62
95/92
23a
8a
8b
2.6
1.5
6.9
O
23d
3.4
78/104
N
O
a
EC50 value means the effective concentration for 50% response of a given compound’s intrinsic maximal response.
Rate of metabolism in human or rat hepatic microsomes.
b
Table 2
In vitro transactivation activity and metabolic stability of compounds 8a,c–e
F3C
Cl
O
N
O
O
O
O
S
N
R
H
MeO
Compound
R
PPAR
EC50 (nM)
c
transactivation
Metabolic clearanceb h/r (
lL/min/mg)
a
8a
8c
8d
8e
Pentyl
(CH2)3OMe
Ph
1.5
11
32
77/62
7/11
—
c
(4-Cl)Ph
8.6
67/71
a,b
See the legends of Table 1.
Not determined.
c
8a with a phenyl group reduced the potency by more than 20-fold
(8d). The decrease in potency was regained by introduction of a
para-chlorine atom onto the phenyl ring of 8d (8e), but the meta-
bolic stability of 8e was comparable to that of 8a. As in the case of
the benzylpyrazole derivatives, the pentyl group proved to be
optimal.

3338
K. Rikimaru et al. / Bioorg. Med. Chem. 20 (2012) 3332–3358
Table 3
In vitro transactivation activity and metabolic stability of compounds 8a,f–h,16,17,23b and 27
F3C
Cl
O
O O
S
H
N
O
O
X
N
Me
MeO
Compound
X
PPAR
c
transactivation
Metabolic clearanceb h/r (
lL/min/mg)
Metobolic clearance in the absence of NADPh h/rc (% remaining)
EC50 (nM)a
8a
8f
1.5
15
77/62
9/6
50.1/13.6
94.8/87.3
8h
2.3
128/189
Me
16d
27
3.1
5.5
5.2
113/78
40/26
20/20
Me Me
73.8/81.7
8g
Me
23c
17
6.7
10
72/15
23/31
OMe
O
a,b
See the legends of Table 1.
c
Metabolic clearance is shown as the percent remaining of compounds after incubation in the absence of NADPH with human and rat hepatic microsomes at 37 °C for 2 h.
Sodium-salt.
d
Table 4
In vitro transactivation activity and metabolic stability of compounds 8f and 13a–d,f,g
R1
R2
X
O
O
O
O
S
N
Me
H
MeO
O
Compound
R1
R2
X
PPAR
EC50 (nM)
c
transactivation
Metabolic clearance h/rb
(lL/min/mg)
a
8f
CF3
Cl
N
15
9/6
13a
13bd
13c
13d
13fe
13g
CF3
CF3
H
Cl
NH2
MeCONH
Cl
H
Cl
Cl
Me
Me
CH
N
N
N
N
94
14/10
<1/<1
18/15
9/9
>10,000
>10,000
190
>10,000
>10,000
c
—
c
N
—
a,b
See the legends of Table 1.
Not determined.
Potassium salt.
c
d
e
2 HCl salt.
Subsequently, effects of modification of the linker between the
tions by which they can adopt suitable conformation for metabolic
enzymes. On the basis of the assumption, introduction of substitu-
central benzene ring and acylsulfonamide moiety on in vitro po-
tency and metabolic stability were examined (Table 3). Desatura-
tion of the ethylene linker (8a) significantly improved metabolic
stability, but decreased potency by 10-fold (8f). A similar tendency
was observed in the benzylpyrazole-based agonists. The high clear-
ance of the ethylene linker analogue (8a) is considered to result
from oxidative metabolism by CYP enzymes as well as non-oxida-
tive metabolism, to which hydrolysis of the acylsulfonamide by
esterases21a mainly contributes,. We hypothesized that compounds
with the flexible ethylene linker tend to have multiple conforma-
ents into the
a-carbon of the carbonyl group was investigated to
block the hydrolysis and/or reduce the flexibility. As shown in
Table 3, introduction of
ated. Compounds with
a
a
-substituent were generally well toler-
-methyl (8h), geminal dimethyl (16),
and
a-methoxy (23c) were almost as potent as the parent com-
pound (8a), still maintaining single-digit nanomolar potency. Dis-
appointingly, the modification tended to decrease metabolic
stability. The result led us to design compounds with vinylene-re-
lated constrained linkers. The cyclopropane analogue 27 showed

K. Rikimaru et al. / Bioorg. Med. Chem. 20 (2012) 3332–3358
3339
Table 5
In vitro transactivation activity and metabolic stability of compounds 8f,i–k,m,o–q
F3C
Cl
N
R
O
O
O
O
S
N
Me
H
Compound
R
PPAR
EC50 (nM)
c
transactivation
Metabolic clearance h/rb
(lL/min/mg)
a
8f
MeO(CH2)2
15
9/6
8i
8j
i-PrO
26
19/19
25/17
16/15
<1/<1
30/19
6/<1
c-PrO(CH2)2O–
MeO(CH2)3O–
HO(CH2)2O–
MeC(@O)CH2)3O–
MeSO2(CH2)3O–
NC(CH2)3O–
6.2
7.4
80
59
320
15
8k
8m
8o
8p
8q
23/19
a,b
See the legends of Table 1.
pounds possessing the vinylene linker and pentylsulfonamide
group were examined. As described in Table 4, the pyridine nitro-
gen as well as two substituents, the 3-chloro and 5-trifluoromethyl
groups, on the pyridine ring were essential for potency. Replace-
ment of the pyridine nitrogen of 8f with a carbon atom resulted
in about a 6-fold decrease in activity (13a) and concomitant
increase in cytotoxicity (data not shown), presumably due to in-
creased lipophilicity. Removal of the 3-chloro or 5-trifluoromethyl
group of 8f (13b,c) led to more than 600-fold decrease in potency.
Substitution of a chlorine atom with the trifluoromethyl group of
8f also decreased potency by more than 10-fold (13d), but the di-
chloro analog 13d still exhibited low submicromolar activity. In
contrast, incorporation of hydrophilic substituents such as an ami-
no (13f) or acetylamino (13g) group was detrimental to in vitro po-
tency. These results indicate that the 2-pyridyl group is preferable,
and the lipophilic 3,5-substituents of the pyridine ring are indis-
pensable for high potency.
Table 6
In vitro transactivation activity and metabolic stability of compounds
8a,r,23a,b,29a,b and 32a,b
F3C
Cl
O
N
O
R2
R1
Having identified the favorable moieties for balancing the po-
tency and metabolic stability, the 4-alkoxy group on the benzene
ring was re-investigated and the results are presented in Table 5.
Isopropoxy analogue 8i was essentially equipotent to 8f, similarly
to the ethylene linker derivatives (see Table 1). Replacement of the
terminal methoxy group of 8f with cyclopropoxy group (8j), or one
carbon elongation of the alkylene spacer (8k) resulted in ca. 2-fold
increase in potency. Furthermore, removal of the terminal methyl
group of 8f reduced the activity by 5-fold (8m). Replacement of
the terminal methoxy group with an acetyl (8o) or methylsulfo-
nylmethyl group (8p) reduced the potency by more than 4-fold,
whereas the 3-cyanopropoxy analog 8q was found to be equipo-
tent to 8f. These findings suggest that incorporation of long and
bulky substituents into the terminus of the alkoxy moiety tends
to have a deleterious effect on activity. Therefore, 2-methoxyeth-
oxy group was the best-balanced in terms of potency and meta-
bolic stability.
a,b
c
See the legends of Table 1.
Not determined.
good potency but was less metabolically stable than the acryl
amide 8f. Introduction of -methyl group into the acryl amide of
8f gave a more potent agonist 8g with acceptable metabolic stabil-
ity. Considering the fact that compounds 8a,g,h showed nanomolar
potency, it is suggested that the linker of 8g would be twisted in
the active conformation similar to 8a,h due to the steric repulsion
a
between the a-methyl group and the ortho hydrogen of the central
benzene ring. Replacement of a methylene group adjacent to the
carbonyl group of 8a with an oxygen atom (17) improved meta-
bolic stability, but decreased potency by ca. 7-fold compared with
8a. The increase in electron density on the carbonyl group may
attenuate the susceptibility of the acylsulfonamide group by ester-
ases. To estimate stability to non-oxidative metabolism metabolic
clearance in the absence of NADPH with hepatic microsomes was
also evaluated for the representative compounds 8a,f and 27. In
accordance with the stability to oxidative metabolism (metabolic
clearance shown in Table 3), the stability to non-oxidative metab-
olism is improved in the order of the rigidity and planarity. Indeed,
compound 8f with the vinylene linker is the most stable to both
oxidative and non-oxidative metabolism, and is consistent with
our hypothesis.
As mentioned above, a large variety of carboxylic acid-based
ligands have been reported as non-TZD PPARc ligands, while only
a few acylsulfonamide-based ligands have been disclosed so far.
Thus, for the purpose of better understanding a role of the acyl-
sulfonamide as a pharmacophore, modification of the acylsulfona-
mide moiety, which is a characteristic structural feature in this
series of PPARc ligands, was carried out and the results are shown
in Table 6. Removal of the sulfonyl group of 23a led to 23b, which
exhibited over 100-fold decrease in potency relative to the parent
acylsulfonamide. On the other hand, replacement of the carbonyl
group of 8a with a methylene group (32a) also reduced potency,
Based on the above-mentioned findings, effects of modification
of the pyridyloxy group on activity and metabolic stability of com-

3340
K. Rikimaru et al. / Bioorg. Med. Chem. 20 (2012) 3332–3358
Table 7
In vitro and in vivo profiles of compound 8f
F3C
Cl
O
N
O
O
O
S
N
Me
H
MeO
O
a
b
PPARs EC50 (nM)
PPAR
c
binding IC50 (nM)
Metobolic clearance h/rc
9/6
(l
L/min/mg)
clogPd
clogDd (pH 7.4)
c
a
d
15
>10,000
>10,000
330
4.04
2.05
Antidiabetic effectse
Pharmokineticsh
f
g
PG ED25 (mg/kg)
0.17
TG ED25 (mg/kg)
0.20
Cmax
AUC0–24 (ng h/mL)
15317
946
a,c
See the legends of Table 1.
b
IC50 value means the concentration of a given compound required for 50% inhibition of the specific binding of [3H]-AD-5061 to human PPAR
c.
d
e
f
Calculated using ACD ver. 10.13
Test compound was administered by oral gavage to male Wistar fatty rats for 7 days.
Effective dose for 25% reduction of plasma glucose.
Effective dose for 25% reduction of plasma triglyceride.
Test compound was administered by oral gavage to male Wistar fatty rats.
g
h
but still maintained 10ꢁ8 M order transactivation. Based on these
results, it clearly indicates that the sulfonyl group is more impor-
tant than the carbonyl group in terms of PPAR activity. There-
improving the metabolic stability. In fact, compounds 8a,29b with
acidic CONHSO2 group (pKa = 4.6),21b which can be deprotonated
in physiological pH, showed better metabolic stability than sul-
fonamide 32a (pKa = 17.5).22 Consequently, acylsulfamide 8r dis-
played the highest activity in this class (EC50 = 1.1 nM);
however, its metabolic stability was comparable to that of 8a.
Although we failed to identify a novel acidic moiety superior to
the acylsulfonamide group, the acylsulfamide was found to be a
reasonable alternative.
c
fore, we conducted further modification of the sulfonamide
group of 32a. Carbamate 32b showed comparable potency to
32a and ‘reverse’ carbamate 29a also essentially equipotent to
32a. Taken together, it is suggested that the position of the
hydrogen bonding acceptor (the sulfonyl or carbonyl groups at
the 5th position from the central benzene ring, highlighted in
red in Table 6) is more important than that of the imide NH
group. Still, the acidity of the imide NH group could also contrib-
ute to high potency. In fact, sulfonylcarbamate 29b designed by
replacement of the butyl group of 29a with pentylsulfonyl group
exhibits nanomolar potency with moderate metabolic stability. It
is noteworthy that the sulfonyl group as a hydrogen bonding
acceptor is tolerated at the 7th position from the central benzene
ring. Moreover, insertion of a NH group between the sulfonyl and
pentyl groups of 8a did not significantly affect either potency or
metabolic stability (8r). From these results, it is suggested that
the imide NH group contributes to adjusting overall lipophilicity,
3.2. Further profiling including in vivo anti-diabetic effects
Further profiling of compound 8f, which showed potent PPAR
c
activity with an EC50 value of 15 nM and good metabolic stability,
was carried out. Compound 8f was found to be a highly selective
PPAR
to 10
gand, binding affinity to PPAR
proximity assay (SPA) using a radioligand [3H]-AD-5061.12 It is
c
l
agonist without showing significant PPAR
M (Table 7). To assess whether 8f is a bona fide PPAR
was measured by scintillation
a
,d agonism up
c
li-
c
Figure 4. Co-crystal structure of 8f (light blue) bound to the PPARc-LBD. Residues
His449, Tyr327, and Lys367 interacting with the acylsulfonamide group of 8f are
highlighted in green. Hydrogen bonds are shown as yellow dotted lines. Tyr473 is
also shown for reference.
Figure 3. Superposition of the co-crystal structures of pyridyloxybenzene 8f
(shown in green) and benzylpyrazole 1 (shown in blue) bound to PPARc-LBD.

K. Rikimaru et al. / Bioorg. Med. Chem. 20 (2012) 3332–3358
3341
3.3. X-ray co-crystallographic studies and computational
analyses
In order to gain insight into molecular basis for the crucial inter-
actions of this series of compounds with PPAR -LBD, co-crystal
c
structure of the protein in complex with compound 8f was deter-
mined at 2.5 Å resolution. The superposition of the co-crystal
structures of 8f and the previously-identified benzylpyrazole 1 is
shown in Figure 3. As we have expected, 8f fully occupies all three
arms of the Y-shaped pocket and adopts a closely similar binding
mode to benzylpyrazole 1.12 It is consistent with the docking mod-
el shown in Figure 2 and the 3-chloro-5-trifluoromethylpyridyloxy
and 2-chloro-4-trifluoromethylbenzyl groups are located at the
essentially same position.
Although there is no interaction between 8f and Tyr473, three
hydrogen bonds between the acylsulfonamide moiety and particu-
lar amino acids of the TZD pocket are observed. As depicted in
Figure 4, the three oxygen atoms of the acylsulfonamide form
hydrogen bonds with amino acid residues adjacent to Tyr473:
the carbonyl oxygen with Tyr327, one sulfonyl oxygen with
Lys367, and the other sulfonyl oxygen with His449. On the other
hand, the imide NH group does not form any hydrogen bonds with
residues in the TZD pocket, which is consistent with the SAR shown
in Table 6. The fact that both sulfonyl oxygens participate in the di-
rect interaction could explain the importance of the sulfonyl group.
Omission of the sulfonyl group of 23a (23b) led to 100-fold de-
crease in activity, while replacement of the carbonyl group of 8a
with a methylene group (32a) gave about 12-fold drop (see Table
6). But it still remains unclear why carbamates 29a and 32b have
comparable potency to sulfonamide 32a.
Figure 5 illustrates the co-crystal structure of 8f seen from a dif-
ferent direction to highlight additional interactions of 8f with the
LBD. The phenolic oxygen of the methoxyethoxy group of 8f forms
a direct hydrogen bond with Arg288, which is consistent with the
SAR finding that the lead compound 2 without the 4-alkoxy group
was less potent than the 4-alkoxy counterparts such as 8a and 23a
(see Table 1). Moreover, there are two lipophilic pockets around
the binding region that accommodates the 2-pyridyloxy group of
8f. The 5-trifluoromethyl group on the pyridine ring binds to a
comparatively large lipophilic pocket, while the chlorine atom at
Figure 5. Co-crystal structure of 8f (shown in white) bound to the PPARc-LBD.
Arg288 interacting with the 2-methoxyethoxy group of 8f is highlighted in green,
and the corresponding hydrogen bond is shown as a yellow dotted line. The
lipophilic pockets accommodating the trifluoromethyl and chloro groups of 8f are
highlighted by yellow circles.
shown that compound 8f proved to be a good PPAR
an IC50 value of 330 nM. Additionally, 8f did not show significant
cytotoxicity up to 30 M (data not shown) presumably due to a
c binder with
l
significant decrease in lipophilicity compared with benzylpyrazole
1 (clogP = 4.04, clogD [pH 7.4] = 2.05 for 8f vs clogP = 5.00, clogP
[pH7.4] = 3.06 for 1). Next, antidiabetic effects of compound 8f
were investigated using a genetically obese rodent model of
T2DM, Wistar fatty rats.12 After once-daily oral dosing for 7 days,
compound 8f produced significant and dose-dependent reductions
in plasma glucose level (PG, ED25 value: 0.17 mg/kg) and triglycer-
ide level (TG, ED25 value: 0.20 mg/kg). In parallel, the pharmacoki-
netic (PK) profile of 8f in Wistar fatty rats was determined
following an oral dose of 0.18 mg/kg. As expected from its high sta-
bility to both oxidative and non-oxidative metabolism (see Table
3), the PK study revealed that 8f shows sufficient plasma exposure
(Cmax = 946 ng/mL, AUC0–24h = 15317 ng h/mL), which contributes
to the potent in vivo efficacy.
2-Pyridyloxybenzene
Phenoxybenzene
F3C
Cl
O
+ 1.0 kcal/mol
+1.6 kcal/mol
X
O
O
O
S
N
Me
H
N
O
O
MeO
O
8f [X = N]
13a [X = CH]
8f-1
13a-1
Figure 6. Superposition of the estimated global minimum conformations of simplified model compounds 8f–1, 13a–1 (shown in orange) and binding conformations of the
corresponding substructures of 8f with PPAR -LBD (shown in green). The putative binding conformation of 13a was obtained by a docking study using the 3-dimesional LBD
c
structure derived from the co-crystal structure of 8f. Then 8f-1 and 13a-1, partial structures of 8f and 13a, were energy-minimized by MMFF94s with the steepest descent
minimum to a maximum gradient of 0.1 kcal/mol/Å separately without the protein. The energy differences between the two conformations of each compound are calculated.

3342
K. Rikimaru et al. / Bioorg. Med. Chem. 20 (2012) 3332–3358
3-position effectively occupies a small ‘dimple’. The hydrophobic
interactions unambiguously indicate the importance of these two
substituents, leading to a plausible explanation of why removal
of one of the two substituents dramatically decreased potency
(see Table 4). In addition to the two lipophilic substituents, the
pyridine nitrogen moderately increased the potency (8f vs 13a in
Table 4). But no interaction of the nitrogen with the protein was
observed in the co-crystal structure of 8f. To further clarify a role
of the nitrogen atom, we conducted energy minimization around
the rotatable bonds of simplified biaryl ether compounds of 8f-1
and 13a-1 using MMFF94s and compared with the corresponding
binding conformations of 2-pyridyloxybenzene 8f and phenoxy-
benzene 13a. With regard to 13a, the putative binding conforma-
tion was obtained by a docking study using the 3-dimesional
LBD structure derived from the co-crystal structure of 8f. As shown
in Figure 6, the estimated global minimum conformation of
pyridyloxybenzene 8f-1 is nearly identical with the actual binding
conformation of the corresponding part seen in the co-crystal
structure. In contrast, the lowest energy structure of phenoxyben-
zene 13a-1 is relatively different from the putative binding confor-
mation of the corresponding part.23
spectra were recorded on a Bruker AVANCE 300 (300 MHz) spec-
trometer or a Varian MERCURY plus 300 (300 MHz) spectrometer.
Chemical shifts are given in d values (ppm) using tetramethylsilane
as the internal standard. All J values are given in hertz. The follow-
ing abbreviations are used: s, singlet; d, doublet; t, triplet; q, quar-
tet; m, multiplet; dd, doublets of doublet; br s, broad singlet.
Elemental analyses (C, H, N) were within 0.3% of theoretical val-
ues and were determined in Takeda Analytical Research Laborato-
ries (Osaka, Japan). Liquid Chromatography-Mass Spectrometry
(LC-MS) analysis was performed on a Shiseido CAPCELL PACK C-
18 UG120 S-3 column in a Waters Alliance 2795 or an Agilent
1100 System equipped with a Waters 2487 absorbance detector
and a Micromass ZQ2000 mass spectrometer, eluted with water
containing 0.05% TFA with a linear gradient of 10% to 100% of
MeCN containing 0.04% TFA. Mass spectra were recorded using
electrospray ionization (ESI) in positive ion mode. Flash chroma-
tography was performed with Merck silica gel 60 (0.063–
0.200 mm) or Fuji Silysia Chemical Purif-Pack SI (60
lM) or Varian
Bond Elut Si (40 M). High-performance liquid chromatography
l
(HPLC) was performed with Nomura Chemical Co., Ltd. Develosil
ODS-UG10 using a Waters HPLC module equipped with a 2487
2-channel UV/VIS detector. Reaction progress was determined by
thin layer chromatography (TLC) analysis on Merck silica gel 60
F254 plates. Visualization was with UV light (254 nm) or iodine.
Yields are of purified compounds and were not optimized.
Reagents and solvents were obtained from commercial sources
and used without further purification. The following abbreviations
are used: AcOH, acetic acid; Ac2O, acetic anhydride; ADDP,
1,10-(azodicarbonyl)dipiperidine; CDI, N,N-carbonyldiimidazole;
DBU, 1,8-diazabicyclo[5.4.0]-7-undecene; DCM, dichloromethane;
DEAD, diethyl azodicarboxylate; DIBAL-H, diisobutylaluminium
hydride; DIPEA, diisopropylethylamine; DMA, N,N-dimethylacet-
amide; DMAP, 4-dimethylaminopyridine; DMF, N,N-dimethyl-
formamide; DMSO, dimethylsulfoxide; EtOAc, ethyl acetate;
EtOH, ethanol; Et2O, diethyl ether; IPE, diisopropyl ether; MeCN,
acetonitrile; MeOH, methanol; MNBA, 2-methyl-6-nitrobenzoic
anhydride; MOMCl, methoxymethyl chloride; MsCl, methansulfo-
nyl chloride; TBAF, tetrabutylammonium fluoride; TEA, triethyl-
amine; TFA, trifluoroacetic acid; THF, tetrahydrofuran; WSC-HCl,
water-soluble carbodiimide hydrochloride (1-ethyl-3-(3-dimethyl-
aminopropyl)carbodiimide hydrochloride).
Again, the results from the co-crystallographic studies and con-
formational calculation can help our understanding of several key
structural requirements for affinity of these compounds. The
molecular basis of the binding mode and the required structural
features of 8f described here offer a significant opportunity to
search further for new PPARc ligands.
4. Conclusion
We have carried out a medicinal chemistry study to explore a
novel class of non-TZD and non-carboxylic acid-based PPAR ago-
c
nists starting from the benzylpyrazole agonist 1. Replacement of
the benzylpyrazole moiety of 1 with other templates derived
from in-house carboxylic acid-based PPARc ligands led to the
identification of the pyridyloxybenzene-acylsulfonamides as new
agonists. The SAR and computational analyses based on the X-
ray co-crystallographic studies revealed the key structural fea-
tures of this chemotype as a PPARc ligand: the acylsulfonamide,
chloro and trifluoromethyl groups on the pyridine ring, 4-
methoxyethoxy side chain on the benzene ring, and vinylene lin-
ker are optimal for balancing the in vitro activity and metabolic
stability.
5.1.1.1. 2-Hydroxy-4-methoxymethoxybenzaldehyde (4a).
To
Consequently, we have succeeded in discovering a new, potent,
a stirred solution of 3 (101 g, 0.730 mol) in acetone (2.0 L) was added
K2CO3 (131 g, 0.948 mol), followed by MOMCl (66.0 mL, 0.877 mol) at
room temperature, and the mixture was stirred at same temperature
overnight. The reaction was quenched with water and extracted with
EtOAc and the combined organic layer was washed with water and
brine, dried over MgSO4, filtered and concentrated under reduced
pressure to give a crude solid, which was purified by silica gel chro-
matography (hexane-EtOAc, 4:1) to give a pale-orange solid. The solid
was recrystallized from EtOAc/hexane to give 8 (127 g, 96%) as white
crystals. Mp 55.5–55.7 °C. 1H NMR (CDCl3): d 3.49 (s, 3H), 5.22 (s, 2H),
6.60 (d, J = 2.3 Hz, 1H), 6.65 (dd, J = 8.5, 2.3 Hz, 1H), 7.34–7.51 (m,
J = 8.7 Hz, 1H), 9.74 (s, 1H), 11.37 (s, 1H). Anal. Calcd for C9H10O4:
C, 59.34; H, 5.53. Found: C, 59.36; H, 5.50.
selective, and orally active PPAR
acylsulfonamide 8f with improved druglike properties. In fact,
compound 8f displayed potent and highly selective PPAR agonism
(EC50 = 15 nM) with good metabolic stability and no cytotoxicity
up to 30 M, presumably due to its decreased lipophilicity com-
c agonist, pyridyloxybenzene-
c
l
pared with the previous benzylpyrazole-acylsulfonamide 1. Fur-
thermore, oral administration of 8f to Wistar fatty rats led to a
robust and dose-dependent reduction in PG and TG levels (ED25
=
0.17, 0.25 mg/kg, respectively). The molecular basis of the binding
mode and the required structural features of 8f described here of-
fer a significant opportunity to search further for new PPAR
c li-
gands. A medicinal chemistry effort is in progress, and the results
will be presented in due course.
5.1.1.2.
2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}-4-
To a stirred solution
5. Experimental section
5.1. Chemistry
(methoxymethoxy)benzaldehyde (5a).
of 4a (74.5 g, 410 mmol) in DMF (450 mL) was added NaH (60%
dispersion in oil, 19.7 g, 491 mmol) at 0 °C and the mixture was
stirred at the temperature for 30 min. Then 2,3-dichloro-5-(trifluo-
romethyl)pyridine (60.0 mL, 433 mmol) was added to the mixture,
which was allowed to warm to room temperature, and stirred at
room temperature for 1 h and at 50 °C for 1 h. The reaction was
quenched with sat. NH4Cl on ice-bath and extracted with EtOAc
5.1.1. General methods
Melting points (mp) were determined on a Büch melting point
B-545 or a Yanagimoto micro melting point apparatus and were
uncorrected. The proton nuclear magnetic resonance (1H NMR)

K. Rikimaru et al. / Bioorg. Med. Chem. 20 (2012) 3332–3358
3343
and the combined organic layer was washed with water and brine,
dried over MgSO4, filtered and concentrated under reduced pres-
sure. The residual solid was purified by silica gel chromatography
(hexane-EtOAc, 9:1 to 2:1) to give a pale-yellow solid, which was
recrystallized from EtOAc/hexane to give 5a (79.0 g, 53%) as white
crystals. Mp 93.9–94.0 °C. 1H NMR (CDCl3): d 3.50 (s, 3H), 5.25 (s,
2H), 6.91 (d, J = 2.3 Hz, 1H), 7.08 (dd, J = 8.7, 2.3 Hz, 1H), 7.92 (d,
J = 8.7 Hz, 1H), 8.03 (d, J = 2.1 Hz, 1H), 8.24 (s, 1H), 9.99 (s, 1H).
Anal. Calcd for C15H11ClF3NO4: C, 49.81; H, 3.07; N, 3.87. Found:
C, 49.87; H, 3.01; N, 3.71.
d 1.21 (t, J = 7.1 Hz, 3H), 2.54–2.62 (m, 2H), 2.77 (t, J = 7.7 Hz,
2H), 3.47 (s, 3H), 4.09 (q, J = 7.1 Hz, 2H), 5.15 (s, 2H), 6.81 (d,
J = 2.4 Hz, 1H), 6.93 (dd, J = 8.5, 2.4 Hz, 1H), 7.24 (d, J = 8.5 Hz,
1H), 7.98 (d, J = 1.9 Hz, 1H), 8.26 (dd, J = 2.2, 1.0 Hz, 1H).
5.1.1.8. Ethyl 3-(2-{[3-chloro-5-(trifluoromethyl)pyridin-2-
yl]oxy}-4-hydroxyphenyl)propanoate (33b).
To a stirred
solution of 33a (27.5 g, 63.4 mmol) in THF (320 mL) was added
conc. HCl (10.0 mL, 120 mmol) and the mixture was stirred at
50 °C for 45 min. After being cooled to room temperature, the reac-
tion was quenched with 1 M NaOH (120 mL) and diluted with
EtOAc and washed with water and brine, dried over MgSO4, filtered
and concentrated under reduced pressure. The residue was puri-
fied by silica gel chromatography (hexane-EtOAc, 19:1 to 4:1) to
give 33b (20.5 g, 83%) as a pale-yellow oil. 1H NMR (CDCl3): d
1.09–1.38 (m, 3H), 2.44–2.68 (m, 2H), 2.68–2.85 (m, 2H), 3.97–
4.25 (m, 2H), 6.61 (d, J = 2.2 Hz, 1H), 6.65–6.77 (m, 1H), 7.18 (d,
J = 8.1 Hz, 1H), 7.98 (d, J = 2.2 Hz, 1H), 8.26 (s, 1H).
5.1.1.3. 2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}benz-
aldehyde (5b).
Compound 5b (a brown oil) was prepared
from 4b and 2,3-dichloro-5-(trifluoromethyl)pyridine in quantita-
tive yield following a similar procedure to provide 5a. 1H NMR
(CDCl3): d 7.22–7.32 (m, 1H), 7.40–7.49 (m, 1H), 7.65–7.75 (m,
1H), 7.99 (dd, J = 7.7, 1.7 Hz, 1H), 8.04 (d, J = 2.3 Hz, 1H), 8.23 (dd,
J = 2.3, 0.9 Hz, 1H), 10.17 (s, 1H).
5.1.1.4. Ethyl (2E)-3-[2-{[3-chloro-5-(trifluoromethyl)pyridin-2-
5.1.1.9. Ethyl (2E)-3-(2-{[3-chloro-5-(trifluoromethyl)pyridin-2-
yl]oxy}-4-(methoxymethoxy)phenyl]acrylate (6a).
To an
yl]oxy}-4-hydroxyphenyl)acrylate (33c).
To a stirred solu-
ice-cooled solution of ethyl diethylphosphonoacetate (2.76 g,
12.3 mmol) in THF (10 mL) was added NaH (60% dispersion in
oil, 482 mg, 12.1 mmol) with stirring and after 30 min, 5a (3.90 g,
10.8 mmol) in DMF (10 mL) was added to the mixture, which
was allowed to warm to room temperature, and stirred for
30 min. The reaction was quenched with sat. NH4Cl and extracted
with EtOAc and the combined organic layer was washed with
water and brine, dried over MgSO4, filtered and concentrated un-
der reduced pressure. The residual oil was purified by silica gel
chromatography (hexane-EtOAc, 19:1 to 65:35) to give 6a
(4.66 g, quant.) as a pale-yellow solid. Recrystallization from
EtOAc/hexane gave white crystals. Mp 73.5–74.5 °C. 1H NMR
(CDCl3): d 1.29 (t, J = 7.2 Hz, 3H), 3.48 (s, 3H), 4.20 (q, J = 7.0 Hz,
2H), 5.19 (s, 2H), 6.38 (d, J = 16.0 Hz, 1H), 6.84 (d, J = 2.4 Hz, 1H),
7.00 (dd, J = 8.7, 2.3 Hz, 1H), 7.64 (d, J = 8.9 Hz, 1H), 7.69 (d,
J = 16.0 Hz, 1H), 8.01 (d, J = 1.7 Hz, 1H), 8.25 (dd, J = 2.2, 1.0 Hz,
1H). Anal. Calcd for C19H17ClF3NO5: C, 52.85; H, 3.97; N, 3.24.
Found: C, 52.87; H, 3.89; N, 3.10.
tion of 6a (52.9 g, 111 mmol) in acetone (500 mL) was added 1 M
HCl (250 mL, 250 mmol) and the mixture was stirred under reflux
for 5 h. After being cooled to room temperature, the reaction was
neutralized with 1 M NaOH (250 mL, 250 mmol) and extracted
with EtOAc and the combined organic layer was washed with
water and brine, dried over MgSO4, filtered and concentrated un-
der reduced pressure. The residual solid was purified by silica gel
chromatography (hexane-EtOAc, 9:1 to 4:1) to give 33c (44.5 g,
quant.) as a white solid. Recrystallization from EtOAc/hexane gave
white crystals. Mp 123.5–124.0 °C. 1H NMR (CDCl3): d 1.28 (t,
J = 7.2 Hz, 3H), 4.20 (q, J = 7.2 Hz, 2H), 5.46 (s, 1H), 6.36 (d,
J = 16.0 Hz, 1H), 6.65 (d, J = 2.4 Hz, 1H), 6.79 (dd, J = 8.4, 2.4 Hz,
1H), 7.59 (d, J = 8.7 Hz, 1H), 7.70 (d, J = 16.0 Hz, 1H), 8.01 (d,
J = 2.3 Hz, 1H), 8.26 (dd, J = 2.2, 1.0 Hz, 1H). Anal. Calcd for
C17H13ClF3NO4: C, 52.66; H, 3.38; N, 3.61. Found: C, 52.74; H,
3.34; N, 3.46.
5.1.1.10. Ethyl (2E)-3-(2-{[3-chloro-5-(trifluoromethyl)pyridin-
2-yl]oxy}-4-hydroxyphenyl)-2-methyl acrylate (33d).
Com-
5.1.1.5. Ethyl (2E)-3-(2-{[3-chloro-5-(trifluoromethyl)pyridin-2-
pound 33d (colorless crystals) was prepared from 6c in 84% yield
following a similar procedure to provide 33c. Mp 101.5–102.0 °C.
1H NMR (CDCl3): d 1.26 (t, J = 7.2 Hz, 3H), 2.01 (d, J = 1.3 Hz, 3H),
4.17 (q, J = 7.2 Hz, 2H), 6.07 (s, 1H), 6.68 (d, J = 2.6 Hz, 1H), 6.77
(dd, J = 8.6, 2.5 Hz, 1H), 7.34 (d, J = 8.5 Hz, 1H), 7.50 (s, 1H), 7.98
(d, J = 1.9 Hz, 1H), 8.23 (d, J = 1.1 Hz, 1H). Anal. Calcd for
yl]oxy}phenyl)acrylate (6b).
Compound 6b (a pale-yellow
oil) was prepared from 5b in 84% yield following a similar proce-
dure to provide 6a. 1H NMR (CDCl3): d (t, J = 7.2 Hz, 3H), 4.22 (q,
J = 7.2 Hz, 2H), 6.49 (d, J = 16.2 Hz, 1H), 7.16 (dd, J = 8.1, 1.1 Hz,
1H), 7.28–7.36 (m, 1H), 7.42–7.50 (m, 1H), 7.71 (dd, J = 7.7,
1.7 Hz, 1H), 7.77 (d, J = 16.2 Hz, 1H), 8.01 (d, J = 1.9 Hz, 1H), 8.24
(dd, J = 2.1, 0.9 Hz, 1H).
C18H15ClF3NO4: C, 53.81; H, 3.76; N, 3.49. Found: C, 53.90; H,
3.74; N, 3.50.
5.1.1.6. Ethyl (2E)-3-[2-{[3-chloro-5-(trifluoromethyl)pyridin-2-
yl]oxy}-4-(methoxymethoxy)phenyl]-2-methylacrylate (6c). Com-
pound 6c (a pale-yellow oil, E/Z = 1.0/0.15, determined by the
integral value in 1H NMR spectra at 6.92 ppm) was prepared from
5a in quantitative yield following a similar procedure to provide
6a. 1H NMR (CDCl3): d 1.25 (t, J = 7.1 Hz, 3H), 2.01 (s, 3H), 3.50 (s,
3H), 4.17 (q, J = 7.0 Hz, 2H), 5.20 (s, 2H), 6.92 (d, J = 2.3 Hz, 1H),
7.01 (dd, J = 8.6, 2.2 Hz, 1H), 7.38 (d, J = 8.7 Hz, 1H), 7.49 (s, 1H),
7.96 (d, J = 1.3 Hz, 1H), 8.23 (s, 1H).
5.1.1.11. Ethyl 3-[2-{[3-chloro-5-(trifluoromethyl)pyridin-2-
yl]oxy}-4-(2-methoxyethoxy)phenyl]propanoate (7a).
To a
stirred solution of 33b (9.90 g, 25.4 mmol), 2-methoxyethanol
(2.50 mL, 31.7 mmol) and tributylphosphine (13.0 mL, 52.2 mmol)
in THF was added potionwise ADDP (7.41 g, 29.4 mmol) at 50 °C,
then the mixture was stirred for 5 min. The mixture was concen-
trated in vacuo, and the residue was washed with IPE and the fil-
trate was concentrated in vacuo. The crude oil was purified by
silica gel chromatography (hexane-EtOAc, 19:1 to 4:1) to give 7a
(10.1 g, 89%) as a white solid. Recrystallization from EtOAc/hexane
gave white needles. Mp 70.0–70.5 °C. 1H NMR (CDCl3): d 1.21 (t,
J = 7.2 Hz, 3H), 2.52–2.62 (m, 2H), 2.77 (t, J = 7.7 Hz, 2H), 3.43 (s,
3H), 3.73 (dd, J = 5.5, 4.0 Hz, 2H), 4.02–4.15 (m, 4H), 6.68 (d,
J = 2.6 Hz, 1H), 6.82 (dd, J = 8.6, 2.5 Hz, 1H), 7.22 (d, J = 8.5 Hz,
1H), 7.98 (d, J = 2.1 Hz, 1H), 8.26 (d, J = 0.9 Hz, 1H). Anal. Calcd
for C20H21ClF3NO5: C, 53.64; H, 4.73; N, 3.13. Found: C, 53.64; H,
4.68; N, 2.95.
5.1.1.7. Ethyl 3-[2-{[3-chloro-5-(trifluoromethyl)pyridin-2-
yl]oxy}-4-(methoxymethoxy)phenyl]propanoate (33a).
A
stirred solution of 6a (4.46 g, 10.3 mmol) in THF (50 mL) was
hydrogenated under atmospheric pressure with 10% Pd/C (wet,
0.75 g, 0.34 mmol) at room temperature for 1 h. The catalyst was
removed by filtration and the filtrate was concentrated in vacuo
to give 33a (4.49 g, quant.) as a pale-yellow oil. 1H NMR (CDCl3):

3344
K. Rikimaru et al. / Bioorg. Med. Chem. 20 (2012) 3332–3358
5.1.1.12. Ethyl 3-{2-{[3-chloro-5-(trifluoromethyl)pyridin-2-
yl]oxy}-4-[2-(diethylamino)-2-oxoethoxy]phenyl}propanoate
1H), 7.69 (d, J = 16.0 Hz, 1H), 8.01 (d, J = 1.7 Hz, 1H), 8.24 (dd,
J = 2.2, 1.0 Hz, 1H). Anal. Calcd for C22H21ClF3NO5: C, 56.00; H,
4.49; N, 2.97. Found: C, 56.02; H, 4.43; N, 2.97.
(7c).
To a stirred solution of 33b (0.68 g, 1.74 mmol) and
K2CO3 (322 mg, 2.33 mmol) in DMF (15 mL) was added 2-chloro-
N,N-diethylacetamide (0.31 g, 2.07 mmol) and the mixture was
stirred at room temperature for 2 h, at 50 °C for 30 min, and at
80 °C for 1 h. Then, additional 2-chloro-N,N-diethylacetamide
(0.30 g, 2.01 mmol) was added to the mixture, which was stirred
at 80 °C for additional 30 min. After being cooled to room temper-
ature, the reaction was acidified with 1 M HCl, and extracted with
EtOAc, and the combined organic layer was washed with sat. NaH-
CO3 and brine, dried over MgSO4, filtered and concentrated under
reduced pressure. The residue was purified by silica gel chroma-
tography (hexane-EtOAc, 9:1 to 1:2) to give crude 7c (1.39 g,
quant.) as a white solid. Recrystallization from EtOAc/hexane gave
white needles. Mp 88.5–89.0 °C. 1H NMR (CDCl3): d 1.13 (t,
J = 7.2 Hz, 3H), 1.21 (td, J = 7.1, 1.8 Hz, 6H), 2.57 (t, J = 7.7 Hz, 2H),
2.76 (t, J = 7.6 Hz, 2H), 3.30–3.50 (m, 4H), 4.09 (q, J = 7.0 Hz, 2H),
4.64 (s, 2H), 6.73 (d, J = 2.6 Hz, 1H), 6.84 (dd, J = 8.4, 2.5 Hz, 1H),
7.24 (d, J = 9.0 Hz, 1H), 7.98 (d, J = 2.1 Hz, 1H), 8.23–8.32 (m, 1H).
Anal. Calcd for C23H26ClF3N2O5: C, 54.93; H, 5.21; N, 5.57. Found:
C, 54.98; H, 5.11; N, 5.46.
5.1.1.17. Ethyl (2E)-3-[2-{[3-chloro-5-(trifluoromethyl)pyridin-
2-yl]oxy}-4-(3-methoxypropoxy)phenyl]acrylate (7i).
Com-
pound 7i (white crystals) was prepared from 33c and 1-bromo-3-
methoxypropane in 70% yield following a similar procedure to pro-
vide 7c. Mp 86.4–86.5 °C (EtOAc/hexane). 1H NMR (CDCl3): d 1.28
(t, J = 7.2 Hz, 3H), 1.91ꢁ2.12 (m, 2H), 3.34 (s, 3H), 3.53 (t,
J = 6.1 Hz, 2H), 4.07 (t, J = 6.2 Hz, 2H), 4.20 (q, J = 7.2 Hz, 2H), 6.36
(d, J = 16.0 Hz, 1H), 6.68 (d, J = 2.6 Hz, 1H), 6.87 (dd, J = 8.7,
2.4 Hz, 1H), 7.63 (d, J = 8.9 Hz, 1H), 7.69 (d, J = 16.0 Hz, 1H), 8.01
(d, J = 2.3 Hz, 1H), 8.26 (d, J = 0.9 Hz, 1H). Anal. Calcd for
C21H21ClF3NO5: C, 54.85; H, 4.60; N, 3.05. Found: C, 54.88; H,
4.47; N, 2.98.
5.1.1.18. 2-[(Triisopropylsilyl)oxy]ethanol.
To a mixture of
ethylene glycol (34 mL) and pyridine (34 mL) was added dropwise
chloro(triisopropyl)silane (10.7 mL, 50 mmol) with stirring at room
temperature over 20 min, then the mixture was stirred for 12 h.
The mixture was diluted with water and extracted with EtOAc.
The aqueous layer was washed with EtOAc. The combined organic
layer was washed with water and brine, dried over MgSO4, filtered
and concentrated under reduced pressure. The residue was puri-
fied by silica gel chromatography (hexane-EtOAc, 20:1 to 5:1) to
give 2-[(triisopropylsilyl)oxy]ethanol (10.5 g, 96%) as a colorless
oil. 1H NMR (CDCl3): d 0.99–1.17 (m, 2H), 2.17 (t, J = 6.22 Hz, 1H),
3.58–3.71 (m, 2H), 3.74–3.85 (m, 2H).
5.1.1.13. Ethyl (2E)-3-[2-{[3-chloro-5-(trifluoromethyl)pyridin-
2-yl]oxy}-4-(2-methoxyethoxy)phenyl]acrylate (7d).
Com-
pound 7d (white feather crystals) was prepared from 33c and
2-methoxyethanol in 60% yield following the procedure to provide
7a. Mp 78.2–78.5 °C (EtOAc/hexane). 1H NMR (CDCl3): d 1.28 (t,
J = 7.1 Hz, 3H), 3.44 (s, 3H), 3.66–3.84 (m, 2H), 4.04–4.34 (m, 4H),
6.37 (d, J = 16.0 Hz, 1H), 6.70 (d, J = 2.4 Hz, 1H), 6.85–6.97 (m,
1H), 7.58–7.75 (m, 2H), 8.01 (d, J = 2.3 Hz, 1H), 8.24 (s, 1H). Anal.
Calcd for C20H19ClF3NO5: C, 53.88; H, 4.30; N, 3.14. Found: C,
54.00; H, 4.30; N, 3.05.
5.1.1.19. Ethyl (2E)-3-[2-{[3-chloro-5-(trifluoromethyl)pyridin-
2-yl]oxy}-4-{2-[(triisopropylsilyl)oxy]ethoxy}phenyl)acrylate
(7j).
Compound 7j (a pale-yellow oil) was prepared from 33c
and 2-[(triisopropylsilyl)oxy]ethanol in 89% yield following a sim-
ilar procedure to provide 7j. 1H NMR (CDCl3): d 0.97–1.15 (m, 21H),
1.28 (t, J = 7.06 Hz, 3H), 3.98–4.12 (m, 4H), 4.20 (q, J = 7.16 Hz, 2H),
6.36 (d, J = 16.20 Hz, 1H), 6.70 (d, J = 2.45 Hz, 1H), 6.89 (dd, J = 8.76,
2.54 Hz, 1H), 7.62 (d, J = 8.67 Hz, 1H), 7.68 (d, J = 16.20 Hz, 1H),
8.01 (d, J = 2.07 Hz, 1H), 8.25 (dd, J = 2.07, 0.94 Hz, 1H).
5.1.1.14. Ethyl (2E)-3-[2-{[3-chloro-5-(trifluoromethyl)pyridin-
2-yl]oxy}-4-(2-methoxyethoxy)phenyl]-2-methylacrylate
(7e). Compound 7e (a colorless oil, E/Z = 1.00/0.13, determined by
the integral value in 1H NMR spectra at 6.78 ppm) was prepared
from 33d and 2-methoxyethanol in 95% yield following the proce-
dure to provide 7a. 1H NMR (CDCl3): d1.23–1.29 (m, 3H), 2.02 (d,
J = 1.5 Hz, 3H), 3.45 (s, 3H), 3.73–3.80 (m, 2H), 4.06–4.23 (m, 4H),
6.78 (d, J = 2.6 Hz, 1H), 6.91 (dd, J = 8.7, 2.4 Hz, 1H), 7.39 (d,
J = 8.7 Hz, 1H), 7.50 (s, 1H), 7.96 (d, J = 2.1 Hz, 1H), 8.22 (d,
J = 1.1 Hz, 1H).
5.1.1.20. Ethyl (2E)-3-{2-{[3-chloro-5-(trifluoromethyl)pyridin-
2-yl]oxy}-4-[2-(2-methyl-1,3-dioxolan-2-yl)ethoxy]phenyl}acry
late (7k).
Compound 7k (colorless crystals) was prepared
from 33c and 2-(2-bromoethyl)-2-methyl-1,3-dioxolane in 74%
yield following a similar procedure to provide 7c. Mp 167–168 °C
(EtOAc/hexane). 1H NMR (CDCl3): d 1.28 (t, J = 7.1 Hz, 3H), 1.39
(s, 3H), 2.18 (t, J = 7.0 Hz, 2H), 3.88–4.02 (m, 4H), 4.11 (t,
J = 7.0 Hz, 2H), 4.20 (q, J = 7.1 Hz, 2H), 6.36 (d, J = 16.0 Hz, 1H),
6.65–6.69 (m, 1H), 6.87 (dd, J = 8.8, 2.4 Hz, 1H), 7.59–7.73 (m,
2H), 8.01 (d, J = 1.9 Hz, 1H), 8.25 (dd, J = 2.1, 0.9 Hz, 1H). Anal. Calcd
for C23H23ClF3NO6: C, 55.04; H, 4.62; N, 2.79. Found: C, 55.07; H,
4.67; N, 2.78.
5.1.1.15. Ethyl (2E)-3-(2-{[3-chloro-5-(trifluoromethyl)pyridin-
2-yl]oxy}-4-isopropoxyphenyl)acrylate (7g).
Compound 7g
(white feather crystals) was prepared from 33c and 2-iodopropane
in 96% yield following a similar procedure to provide 7c. Mp 84.5–
85.0 °C (EtOAc/hexane). 1H NMR (CDCl3): d 1.28 (t, J = 7.1 Hz, 3H),
1.35 (d, J = 6.0 Hz, 6H), 4.20 (q, J = 7.1 Hz, 2H), 4.44–4.64 (m, 1H),
6.35 (d, J = 16.0 Hz, 1H), 6.64 (d, J = 2.4 Hz, 1H), 6.84 (dd, J = 8.6,
2.5 Hz, 1H), 7.62 (d, J = 8.9 Hz, 1H), 7.69 (d, J = 16.0 Hz, 1H), 8.01
(d, J = 1.7 Hz, 1H), 8.25 (dd, J = 2.2, 1.0 Hz, 1H). Anal. Calcd for
5.1.1.21. Ethyl (2E)-3-{2-{[3-chloro-5-(trifluoromethyl)pyridin-
2-yl]oxy}-4-[3-(methylsulfonyl)propoxy]-phenyl}acrylate
C20H19ClF3NO4: C, 55.89; H, 4.46; N, 3.26. Found: C, 55.87; H,
4.39; N, 3.31.
(7l).
Compound 7l (white crystals) was prepared from 33c
and 3-(methylsulfonyl)propyl 4-methylbenzenesulfonate25 in 97%
yield following a similar procedure to provide 7c. Mp 190.6–
191.0 °C (EtOAc/hexane). 1H NMR (CDCl3): d1.29 (t, J = 7.2 Hz,
3H), 2.31ꢁ2.42 (m, 2H), 2.96 (s, 3H), 3.19ꢁ3.29 (m, 2H), 4.14 (t,
J = 5.8 Hz, 2H), 4.20 (q, J = 7.2 Hz, 2H), 6.38 (d, J = 16.0 Hz, 1H),
6.68 (d, J = 2.4 Hz, 1H), 6.86 (dd, J = 8.7, 2.4 Hz, 1H), 7.62ꢁ7.73
(m, 2H), 8.02 (d, J = 1.9 Hz, 1H), 8.25 (dd, J = 2.1, 0.9 Hz, 1H). Anal.
Calcd for C21H21ClF3NO6S: C, 49.66; H, 4.17; N, 2.76. Found: C,
49.55; H, 4.16; N, 2.66.
5.1.1.16. Ethyl (2E)-3-{2-{[3-chloro-5-(trifluoromethyl)pyridin-
2-yl]oxy}-4-[2-(cyclopropyloxy)ethoxy]-phenyl}acrylate
(7h). Compound 7h (white crystals) was prepared from 33c and
2-cyclopropoxyethanol24 in 72% yield following a similar proce-
dure to provide 7a. Mp 75.4–75.9 °C (EtOAc/hexane). 1H NMR
(CDCl3):
d
0.44ꢁ0.56 (m, 2H), 0.56–0.65 (m, 2H), 1.28 (t,
J = 7.1 Hz, 3H), 3.31–3.44 (m, 1H), 3.78–3.88 (m, 2H), 4.06–4.14
(m, 2H), 4.20 (q, J = 7.2 Hz, 2H), 6.36 (d, J = 16.2 Hz, 1H), 6.69 (d,
J = 2.4 Hz, 1H), 6.88 (dd, J = 8.8, 2.4 Hz, 1H), 7.62 (d, J = 8.9 Hz,

K. Rikimaru et al. / Bioorg. Med. Chem. 20 (2012) 3332–3358
3345
5.1.1.22. Ethyl (2E)-3-[2-{[3-chloro-5-(trifluoromethyl)pyridin-
2-yl]oxy}-4-(3-cyanopropoxy)phenyl]-acrylate (7m). Com-
8.25 (dd, J = 2.1, 0.9 Hz, 1H). Anal. Calcd for C18H15ClF3NO5: C,
51.75; H, 3.62; N, 3.35. Found: C, 52.00; H, 3.69; N, 3.17.
pound 7m (colorless crystals) was prepared from 33c and 4-bro-
mobutyronitrile in 94% yield following a similar procedure to
provide 7c. Mp 106–107 °C (EtOAc/hexane). 1H NMR (CDCl3): d
1.29 (t, J = 7.1 Hz, 3H), 2.09–2.22 (m, 2H), 2.59 (t, J = 7.0 Hz, 2H),
4.10 (t, J = 5.7 Hz, 2H), 4.20 (q, J = 7.1 Hz, 2H), 6.38 (d, J = 16.0 Hz,
1H), 6.69 (d, J = 2.4 Hz, 1H), 6.87 (dd, J = 8.9, 2.4 Hz, 1H), 7.62–
7.73 (2H, m), 8.02 (d, J = 2.1 Hz, 1H), 8.25 (dd, J = 2.1, 0.9 Hz, 1H).
Anal. Calcd for C21H18ClF3N2O4: C, 55.46; H, 3.99; N, 6.16. Found:
C, 55.39; H, 3.94; N, 6.26.
5.1.1.26.
yl]oxy}-4-(2-methoxyethoxy)phenyl]-2-methylacrylic
(34e). Compound 34e (white needles) was prepared from 7e
in 79% yield following a similar procedure to provide 34a. Mp
122.0–122.5 °C (EtOAc/hexane). 1H NMR (CDCl3):
2.04 (d,
J=1.3 Hz, 3H), 3.45 (s, 3H), 3.72–3.78 (m, 2H), 4.09–4.18 (m, 2H),
6.76 (d, J = 2.6 Hz, 1H), 6.91 (dd, J = 8.7, 2.4 Hz, 1H), 7.42 (d,
J = 8.7 Hz, 1H), 7.64 (s, 1H), 7.97 (d, J = 2.1 Hz, 1H), 8.22 (d,
J = 0.9 Hz, 1H). Anal. Calcd for C19H17ClF3NO5: C, 52.85; H, 3.97;
N, 3.24. Found: C, 52.98; H, 4.03; N, 3.23.
(2E)-3-[2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-
acid
d
5.1.1.23. 3-[2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}-
4-(2-methoxyethoxy)phenyl]propanoic acid (34a).
To a
stirred solution of 7a (5.21 g, 11.6 mmol) in THF (12 mL) and EtOH
(12 mL) was added 1 M NaOH (25.0 mL, 25.0 mmol) and the mix-
ture was stirred at 50 °C for 30 min. After being cooled to room
temperature, the reaction was acidified with 1 M HCl (25.0 mL,
25.0 mmol), and extracted with EtOAc, and the combined organic
layer was washed with brine, dried over MgSO4, filtered and con-
centrated under reduced pressure to give a white solid, which
was recrystallized from EtOAc/hexane to give 34a (4.15 g, 85%)
as white needles. Mp 116–117 °C. 1H NMR (CDCl3): d 2.56–2.69
(m, 2H), 2.78 (t, J = 7.3 Hz, 2H), 3.43 (s, 3H), 3.73 (dd, J = 5.5,
4.0 Hz, 2H), 4.09 (dd, J = 5.5, 4.0 Hz, 2H), 6.68 (d, J = 2.4 Hz, 1H),
6.82 (dd, J = 8.5, 2.6 Hz, 1H), 7.22 (d, J = 8.5 Hz, 1H), 7.98 (d,
J = 2.1 Hz, 1H), 8.25 (dd, J = 2.2, 1.0 Hz, 1H). Anal. Calcd for
5.1.1.27.
oxy}-4-(2-methoxyethoxy)phenyl]-2-methylpropanoic
(34f). Compound 34f (white crystals) was prepared from 7e
in 52% yield following the procedure to provide 34b. Mp 129.5–
131.0 °C. 1H NMR (CDCl3): d 1.15 (d, J = 6.8 Hz, 3H), 2.53 (dd,
J = 13.3, 7.4 Hz, 1H), 2.74–2.93 (m, 2H), 3.43 (s, 3H), 3.68–3.78
(m, 2H), 4.05–4.12 (m, 2H), 6.69 (d, J = 2.6 Hz, 1H), 6.81 (dd,
J = 8.5, 2.6 Hz, 1H), 7.20 (d, J = 8.5 Hz, 1H), 7.99 (d, J = 2.1 Hz, 1H),
8.26 (d, J = 0.9 Hz, 1H). Anal. Calcd for C19H19ClF3NO5: C, 52.60;
H, 4.41; N, 3.23. Found: C, 52.81; H, 4.52; N, 3.24.
3-[2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]-
acid
5.1.1.28. (2E)-3-(2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}-4-
isopropoxyphenyl)acrylic acid (34g).
Compound 34g (a white pow-
C
18H17ClF3NO5: C, 51.50; H, 4.08; N, 3.34. Found: C, 51.67; H,
der) was prepared from 7g in 63% yield following a similar procedure to
provide 34a. Mp 138.0–139.5 °C (EtOAc/hexane). 1H NMR (CDCl3): d 1.35
(d, J = 6.0 Hz, 6H), 4.39–4.72 (m, 1H), 6.35 (d, J = 16.0 Hz, 1H), 6.64 (d,
J = 2.4 Hz, 1H), 6.85 (dd, J = 8.9, 2.4 Hz, 1H), 7.63 (d, J = 8.9 Hz, 1H), 7.77
(d, J = 16.0 Hz, 1H), 8.01 (d, J = 2.1 Hz, 1H), 8.26 (d, J = 0.9 Hz, 1H). Anal.
Calcd for C18H15ClF3NO4: C, 53.81; H, 3.76; N, 3.49. Found: C, 54.00; H,
3.81; N, 3.68.
4.02; N, 3.25.
5.1.1.24. 3-(2-{[3-Chloro-5-(trifluoromethyl)pyridin-2yl]oxy}-
phenyl)propanoic acid (34b).
A stirred solution of 6b
(6.13 g, 16.5 mmol) in THF (50 mL) was hydrogenated under atmo-
spheric pressure with 10% Pd/C (wet, 3.46 g, 1.63 mmol) at room
temperature for 2 h. The catalyst was removed by filtration and
the filtrate was concentrated in vacuo. The residual oil was purified
by silica gel chromatography (hexane-EtOAc, 19:1 to 3:2) to give a
mixture of ethyl 3-(2-{[3-chloro-5-(trifluoromethyl)pyridin-2-
yl]oxy}phenyl)propanoate (7b) and ethyl 3-phenylpropanoate
(7b0) (4.14 g, 67%, calculated as pure 7b) as a yellow oil.
5.1.1.29. (2E)-3-{2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}-
4-[2-(cyclopropyloxy)ethoxy]phenyl}acrylic acid (34h).
Com-
pound 34h (white crystals) was prepared from 7h and 2-(cyclopropyl-
oxy)ethanol24 in 97% yield following a similar procedure to provide
34a. Mp 147–150 °C (EtOAc/hexane). 1H NMR (CDCl3): d 0.44–0.56
(m, 2H), 0.57–0.65 (m, 2H), 3.38 (tt, J = 6.0, 3.0 Hz, 1H), 3.85 (dd,
J = 5.5, 4.1 Hz, 2H), 4.12 (dd, J = 5.5, 4.0 Hz, 2H), 6.37 (d, J = 16.2 Hz,
1H), 6.69 (d, J = 2.4 Hz, 1H), 6.90 (dd, J = 8.7, 2.4 Hz, 1H), 7.64 (d,
J = 8.7 Hz, 1H), 7.77 (d, J = 16.0 Hz, 1H), 8.02 (d, J = 2.3 Hz, 1H), 8.25
(dd, J = 2.2, 1.0 Hz, 1H). Anal. Calcd for C22H17ClF3NO5: C, 54.13; H,
3.86; N, 3.16. Found: C, 54.25; H, 3.91; N, 2.94.
To a stirred solution of the mixture of 7b and 7b0 (4.14 g,
11.1 mmol, calculated as pure 7b) in THF (10 mL) and EtOH
(10 mL) was added 1 M NaOH (25.0 mL, 25.0 mmol) and the mix-
ture was stirred at 50 °C for 30 min. After being cooled to room
temperature, the reaction was acidified with 1 M HCl (25.0 mL,
25.0 mmol), and diluted with toluene and concentrated in vacuo
to remove THF and EtOH, The resultant solid was dissolved into
EtOAc and water, and the separated organic layer was washed with
water and brine, dried over MgSO4, filtered and concentrated un-
der reduced pressure to give a crude solid, which was recrystal-
lized from EtOAc/hexane to give 34b (2.71 g, 71%) as white
feather crystals. Mp 99.5–100.0 °C. 1H NMR (CDCl3): d 2.51–2.76
(m, 2H), 2.86 (t, J = 7.5 Hz, 2H), 7.10 (dd, J = 7.8, 1.4 Hz, 1H),
7.18–7.45 (m, 3H), 7.99 (d, J = 2.3 Hz, 1H), 8.25 (dd, J = 2.1, 0.9 Hz,
1H). Anal. Calcd for C15H11ClF3NO3: C, 52.11; H, 3.21; N, 4.05.
Found: C, 52.16; H, 3.09; N, 4.17.
5.1.1.30. (2E)-3-[2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}-
4-(3-methoxypropoxy)phenyl]acrylic acid (34i).
Compound
34i (white crystals) was prepared from 7i in 64% yield following a sim-
ilar procedure to provide 34a. Mp 131–133 °C (EtOAc/hexane). 1H
NMR (CDCl3): d 2.05 (tt, J = 6.2 Hz, 2H), 3.34 (s, 3H), 3.54 (t,
J = 6.0 Hz, 2H), 4.08 (t, J = 6.3 Hz, 2H), 6.36 (d, J = 16.0 Hz, 1H), 6.68
(d, J = 2.4 Hz, 1H), 6.88 (dd, J = 8.9, 2.4 Hz, 1H), 7.65 (d, J = 8.9 Hz,
1H), 7.76 (d, J = 16.2 Hz, 1H), 8.02 (d, J = 2.3 Hz, 1H), 8.26 (dd, J = 2.0,
0.8 Hz, 1H). Anal. Calcd for C19H17ClF3NO5ꢀ0.15hexane: C, 53.75; H,
4.33; N, 3.15. Found: C, 53.45; H, 4.15; N, 2.87.
5.1.1.25.
(2E)-3-[2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-
Com-
yl]oxy}-4-(2-methoxyethoxy)phenyl]acrylic acid (34d).
5.1.1.31. (2E)-3-(2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}-4-
pound 34d (white feather crystals) was prepared from 7d in 79%
yield following a similar procedure to provide 34d. Mp 156.5–
157.5 °C (EtOAc/hexane). 1H NMR (CDCl3): d 3.44 (s, 3H), 3.72–
3.77 (m, 2H), 4.14 (dd, J = 5.4, 3.9 Hz, 2H), 6.37 (d, J = 16.0 Hz,
1H), 6.70 (d, J = 2.4 Hz, 1H), 6.91 (dd, J = 8.8, 2.5 Hz, 1H), 7.64 (d,
J = 8.9 Hz, 1H), 7.77 (d, J = 16.2 Hz, 1H), 8.02 (d, J = 1.9 Hz, 1H),
{2-[(triisopropylsilyl)oxy]ethoxy}phenyl)acrylic acid (34j).
Com-
pound 34j (a white solid) was prepared from 7j in 85% yield following
a similar procedure to provide 34a. 1H NMR (CDCl3): d 0.95–1.17 (m,
21H), 3.88–4.20 (m, 4H), 6.36 (d, J = 16.0 Hz, 2H), 6.70 (d, J = 2.5 Hz,
1H), 6.90 (dd, J = 8.7, 2.5 Hz, 1H), 7.64 (d, J = 16.0 Hz, 1H), 7.76 (d,
J = 16.0 Hz, 1H), 8.02 (dd, J = 2.3 Hz, 1H), 8.25 (d, J = 2.3 Hz, 1H).

3346
K. Rikimaru et al. / Bioorg. Med. Chem. 20 (2012) 3332–3358
5.1.1.32.
(2E)-3-{2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-
5.1.1.37. 3-{2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}-
yl]oxy}-4-[2-(2-methyl-1,3-dioxolan-2-yl)ethoxy]phenyl}acrylic
acid (34k). Compound 34k (colorless crystals) was prepared
4-[2-(diethylamino)-2-oxoethoxy]phenyl}-N-(pentylsulfonyl)
propanamide (8b).
To a stirred solution of 7c (3.31 g,
from 7k in 69% yield following a similar procedure to provide
34a. Mp 144–146 °C (EtOAc/hexane). 1H NMR (CDCl3): d 1.39 (s,
3H), 2.18 (t, J = 7.1 Hz, 2H), 3.88–4.02 (m, 4H), 4.11 (t, J = 7.1 Hz,
4H), 6.36 (d, J = 16.0 Hz, 1H), 6.67 (d, J = 2.4 Hz, 1H), 6.84–6.92
(m, 1H), 7.64 (d, J = 8.9 Hz, 1H), 7.71–7.80 (m, 1H), 8.02 (d,
J = 2.1 Hz, 1H), 8.23–8.28 (m, 1H). Anal. Calcd for C21H19ClF3NO6:
C, 53.23; H, 4.04; N, 2.96. Found: C, 53.30; H, 4.15; N, 2.85.
6.58 mmol) in THF (15 mL) and EtOH (15 mL) was added 1 M
NaOH (15.0 mL, 15.0 mmol) and the mixture was stirred at 50 °C
for 1 h. After being cooled to room temperature, the reaction was
acidified with 1 M HCl (15.0 mL, 15.0 mmol), and extracted with
EtOAc, and the combined organic layer was washed with brine,
dried over MgSO4, filtered and concentrated under reduced pres-
sure to give crude 3-{2-{[3-chloro-5-(trifluoromethyl)pyridin-2-
yl]oxy}-4-[2-(diethylamino)-2-oxoethoxy]phenyl}-propanoic acid
(34c, 2.91 g, 93%) as a pale-yellow solid. 1H NMR (CDCl3): d 1.13
(t, J = 7.2 Hz, 3H), 1.20 (t, J = 7.1 Hz, 3H), 2.63 (t, J = 7.3 Hz, 2H),
2.78 (t, J = 7.5 Hz, 2H), 3.31–3.48 (m, 4H), 4.64 (s, 2H), 6.73 (d,
J = 2.6 Hz, 1H), 6.84 (dd, J = 8.5, 2.4 Hz, 1H), 7.19–7.28 (m, 1H),
7.99 (d, J = 2.3 Hz, 1H), 8.25 (d, J = 1.3 Hz, 1H).
To a stirred solution of crude 34c (2.23 g, 4.71 mmol) in THF
(30 mL) was added CDI (1.17 g, 7.23 mmol) and the mixture was
stirred at reflux for 1 h. After being cooled to room temperature,
was added pentane-1-sulfonamide (1.07 g, 7.08 mmol) followed
by DBU (1.0 mL, 6.96 mmol) to the mixture and the mixture was
stirred at the same temperature overnight. The reaction was
quenched with 1 M HCl and diluted with EtOAc and the organic
layer was washed with sat. NaHCO3 and brine, dried over MgSO4,
filtered and concentrated under reduced pressure. The residual so-
lid was purified by silica gel chromatography (hexane-EtOAc,
85:15 to 7:3) to give a pale-yellow solid, which was recrystallized
from EtOAc/IPE to give 8b (1.96 g, 69%) as a white powder. Mp
111–113 °C. 1H NMR (CDCl3): d 0.85–0.94 (m, 3H), 1.12 (t,
J = 7.2 Hz, 3H), 1.19 (t, J = 7.1 Hz, 3H), 1.24–1.46 (m, 4H), 1.60–
1.87 (m, 2H), 2.54 (t, J = 7.3 Hz, 2H), 2.92 (t, J = 7.3 Hz, 2H), 3.15–
3.25 (m, 2H), 3.29–3.46 (m, 4H), 4.63 (s, 2H), 6.59 (d, J = 2.4 Hz,
1H), 6.79 (dd, J = 8.5, 2.6 Hz, 1H), 7.19 (d, J = 8.5 Hz, 1H), 8.06 (d,
J = 2.3 Hz, 1H), 8.33 (dd, J = 2.3, 0.9 Hz, 1H), 9.04 (s, 1H). Anal. Calcd
for C26H33ClF3N3O6S: C, 51.36; H, 5.47; N, 6.91. Found: C, 51.15; H,
5.45; N, 6.85.
5.1.1.33.
yl]oxy}-4-[3-(methylsulfonyl)propoxy]-phenyl}acrylic
(34l). Compound 34l (white crystals) was prepared from 7l
(2E)-3-{2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-
acid
and 3-(methylsulfonyl)propyl tosylate25 in 83% yield following a
similar procedure to provide 34a. Mp 202–203 °C (EtOAc/hexane).
1H NMR (CDCl3): d 2.08–2.19 (m, 2H), 3.01 (s, 3H), 3.21–3.29 (m,
2H), 4.12 (t, J = 6.1 Hz, 2H), 6.43 (d, J = 16.2 Hz, 1H), 6.93–7.00
(m, 2H), 7.44 (d, J = 16.0 Hz, 1H), 7.87 (d, J = 9.8 Hz, 1H), 8.51 (d,
J = 1.1 Hz, 1H), 8.64 (d, J = 2.3 Hz, 1H). Anal. Calcd for
C19H17ClF3NO6S: C, 47.56; H, 3.57; N, 2.92. Found: C, 47.33; H,
3.67; N, 2.91.
5.1.1.34.
(2E)-3-[2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-
Com-
yl]oxy}-4-(3-cyanopropoxy)phenyl]acrylic acid (34m).
pound 34m (colorless crystals) was prepared from 7m in 78% yield
following a similar procedure to provide 34a. Mp 183–185 °C
(EtOAc/hexane). 1H NMR (CDCl3): d 2.10–2.22 (m, 2H), 2.59 (t,
J = 7.0 Hz, 2H), 4.11 (t, J = 5.7 Hz, 2H), 6.38 (d, J = 16.0 Hz, 1H), 6.69
(d, J = 2.4 Hz, 1H), 6.88 (dd, J = 8.7, 2.4 Hz, 1H), 7.66 (d, J = 8.7 Hz,
1H), 7.77 (d, J = 16.0 Hz, 1H), 8.03 (d, J = 2.1 Hz, 1H), 8.26 (d,
J = 1.1 Hz, 1H). Anal. Calcd for C19H14ClF3N2O4: C, 53.47; H, 3.31; N,
6.56. Found: C, 53.51; H, 3.37; N, 6.54.
5.1.1.35. 3-[2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}-
4-(2-methoxyethoxy)phenyl]-N-(pentylsulfonyl)propanamide
(8a).
To a stirred solution of 34a (3.49 g, 8.31 mmol) in THF
(40 mL) was added CDI (2.08 g, 12.8 mmol) and the mixture was
stirred under reflux for 1 h. After being cooled to room temperature,
was added pentane-1-sulfonamide (1.63 g, 10.8 mmol), followed
by DBU (2.0 mL, 13.4 mmol) and the mixture was stirred at the
same temperature overnight. The mixture was concentrated in va-
cuo and the residue was dissolved into EtOAc and the organic layer
was washed with 1 M HCl, sat. NaHCO3, water and brine, dried over
MgSO4, filtered and concentrated under reduced pressure. The res-
idue was purified by silica gel chromatography (hexane-EtOAc, 4:1
to 1:1) to give a white solid, which was recrystallized from EtOAc/
hexane to give 8a (1.62 g, 35%) as white feather crystals. Mp 140–
142 °C. 1H NMR (CDCl3): d 0.83–0.94 (m, 3H), 1.23–1.42 (m, 4H),
1.59–1.72 (m, 2H), 2.55 (t, J = 7.1 Hz, 2H), 2.95 (t, J = 7.1 Hz, 2H),
3.12–3.20 (m, 2H), 3.41 (s, 3H), 3.66–3.73 (m, 2H), 4.00–4.07 (m,
2H), 6.50 (d, J = 2.5 Hz, 1H), 6.77 (dd, J = 8.5, 2.5 Hz, 1H), 7.18 (d,
J = 8.5 Hz, 1H), 8.06 (d, J = 2.2 Hz, 1H), 8.36 (d, J = 1.4 Hz, 1H), 8.99
(s, 1H). Anal. Calcd for C23H28ClF3N2O6S: C, 49.95; H, 5.10; N, 5.07.
Found: C, 50.02; H, 5.03; N, 5.04.
5.1.1.38. 3-Methoxypropane-1-sulfonamide.
To a solution
of 1-bromo-3-methoxypropane (19.5 g, 0.127 mol) in DMF
(200 mL) was added potassium thioacetate (15.2 g, 0.133 mol),
and the mixture was stirred overnight at room temperature. Water
was added to the reaction mixture, and the mixture was extracted
with Et2O. The organic layer was washed with water and saturated
brine, dried over MgSO4, filtrated and concentrated to give a yellow
oil.
To a solution of the obtained oil in Et2O (200 mL) was added 1 M
NaOH (250 mL, 250 mmol) at 0 °C, and the mixture was stirred at
the same temperature. After 1 h, 12 M NaOH (20 mL, 240 mmol)
and MeOH (50 mL) were added, and the mixture was stirred at
room temperature for 20 min. Conc. HCl (45 mL) was added to
the reaction mixture, and the mixture was extracted with Et2O.
The organic layer was washed with water, sat. NaHCO3 and brine,
dried over MgSO4, filtrated and concentrated.
Into a solution of the obtained residue in acetic acid (200 mL)
and water (200 mL) was carefully bubbled gaseous chlorine over
2 h to prevent the reaction temperature from rising to more than
15 °C. Gaseous nitrogen was bubbled at room temperature for
1 h, and the reaction mixture was added dropwise to an ice-cooled
sat. NaHCO3, and the mixture was extracted with Et2O. The organic
layer was washed with sat. NaHCO3, 10% NaS2O3 and brine, dried
over MgSO4, filtrated and concentrated to give a pale-yellow oil.
A solution of the obtained oil in THF (10 mL) was added drop-
wise to a solution of 28% NH3 (50 mL) and THF (50 mL) at 0 °C,
and the mixture was subsequently stirred for 30 min. The reaction
mixture was concentrated in vacuo and the concentrate was dis-
solved in EtOAc. The organic layer was washed with water and
5.1.1.36. 3-(2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}-
phenyl)-N-(pentylsulfonyl)propanamide (2).
Compound 2
(white crylstals) was prepared from 34b and pentane-1-sulfon-
amide in 69% yield following a similar procedure to provide 8a.
Mp 97–100 °C (EtOAc/hexane). 1H NMR (CDCl3): d 0.84–0.97 (m,
3H), 1.22–1.42 (m, 4H), 1.52–1.69 (m, 2H), 2.60 (t, J = 7.3 Hz, 2H),
3.04 (t, J = 7.3 Hz, 2H), 3.09–3.18 (m, 2H), 6.88–6.99 (m, 1H),
7.13–7.41 (m, 3H), 8.09 (d, J = 2.3 Hz, 1H), 8.37 (dd, J = 2.2, 0.8 Hz,
1H), 8.99 (s, 1H). Anal. Calcd for C20H22ClF3N2O4S: C, 50.16; H,
4.63; N, 5.85. Found: C, 50.10; H, 4.56; N, 5.92.

K. Rikimaru et al. / Bioorg. Med. Chem. 20 (2012) 3332–3358
3347
brine, dried (MgSO4), filtrated and concentrated to give an orange
oil. The obtained oil was dissolved in a suspension of activated
carbon in ethyl acetate, and the mixture was stirred at room tem-
perature for 1 h. The mixture was filtrated and concentrated to give
3-methoxypropane-1-sulfonamide (0.88 g, 5%) as an orange solid.
1H NMR (CDCl3): d 1.86–2.25 (m, 2H), 3.19–3.28 (m, 2H), 3.35 (s,
3H), 3.53 (t, J = 5.8 Hz, 2H), 4.71 (s, 2H).
1 M HCl, sat. NaHCO3, water and brine, dried over MgSO4, filtered
and evaporated under reduced pressure. The residual oil was
purified by silica gel chromatography (hexane-EtOAc, 19:1 to
7:3) to give a white solid, which was recrystallized from EtOAc/
hexane to give 8f (763 mg, 58%) as white crystals. Mp 125.5–
126.0 °C. 1H NMR (CDCl3): d 0.89 (t, J = 7.2 Hz, 3H), 1.24–1.48
(m, 4H), 1.75–1.90 (m, 2H), 3.44 (s, 3H), 3.45–3.52 (m, 2H),
3.66–3.84 (m, 2H), 4.02–4.30 (m, 2H), 6.37 (d, J = 15.8 Hz, 1H),
6.71 (d, J = 2.4 Hz, 1H), 6.91 (dd, J = 8.8, 2.4 Hz, 1H), 7.61 (d,
J = 8.9 Hz, 1H), 7.73 (s, 1H), 7.79 (d, J = 15.8 Hz, 1H), 8.03 (d,
J = 2.1 Hz, 1H), 8.25 (dd, J = 2.1, 0.9 Hz, 1H). Anal. Calcd for
5.1.1.39. 3-[2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}-4-(2-
methoxyethoxy)phenyl]-N-[(3-methoxypropyl)sulfonyl]propana-
mide (8c).
Compound 8c (white feather crystals) was prepared
from 34a and 3-methoxypropane-1-sulfonamide in 50% yield follow-
ing the procedure to provide 8a. Mp 112–113 °C (EtOAc/hexane). 1H
NMR (CDCl3): d 1.77–1.92 (m, 2H), 2.55 (t, J = 7.2 Hz, 2H), 2.97 (t,
J = 7.2 Hz, 2H), 3.23–3.30 (m, 2H), 3.31 (s, 3H), 3.36–3.41 (m, 2H),
3.42 (s, 3H), 3.66–3.83 (m, 2H), 3.96–4.15 (m, 2H), 6.50 (d, J = 2.6 Hz,
1H), 6.78 (dd, J = 8.5, 2.4 Hz, 1H), 7.19 (d, J = 8.5 Hz, 1H), 8.08 (d,
J = 2.3 Hz, 1H), 8.38 (dd, J = 2.3, 0.9 Hz, 1H), 9.04 (s, 1H). Anal. Calcd
for C22H26ClF3N2O7S: C, 47.61; H, 4.72; N, 5.05. Found: C, 47.64; H,
4.70; N, 4.97.
C23H26ClF3N2O6S: C, 50.14; H, 4.76; N, 5.08. Found: C, 50.24; H,
4.86; N, 5.16.
5.1.1.43. (2E)-3-[2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-
yl]oxy}-4-(2-methoxyethoxy)phenyl]-2-methyl-N-(pentylsulfo-
nyl)acrylamide (8g).
Compound 8g (white crystals) was pre-
pared from 34e and pentane-1-sulfonamide in 54% yield following
a similar procedure to provide 8f. Mp 108–111 °C (EtOAc/hexane).
1H NMR (CDCl3): d 0.85–0.94 (m, 3H), 1.24–1.48 (m, 4H), 1.75–1.90
(m, 2H), 2.07 (d, J = 1.3 Hz, 3H), 3.45 (s, 3H), 3.45–3.52 (m, 2H),
3.70–3.81 (m, 2H), 4.09–4.24 (m, 2H), 6.78 (d, J = 2.4 Hz, 1H),
6.92 (dd, J = 8.7, 2.4 Hz, 1H), 7.30–7.43 (m, 2H), 7.87 (s, 1H), 8.00
(d, J = 1.9 Hz, 1H), 8.25 (dd, J = 2.1, 0.9 Hz, 1H). Anal. Calcd for
5.1.1.40. 3-[2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}-4-(2-
methoxyethoxy)phenyl]-N-(phenylsulfonyl)propanamide
(8d).
Compound 8d (white feather crystals) was prepared from
34a and benzenesulfonamide in 51% yield following a similar proce-
dure to provide 8d. Mp 108–109 °C (EtOAc/hexane). 1H NMR (CDCl3):
d 2.46 (t, J = 7.2 Hz, 2H), 2.85 (t, J = 7.1 Hz, 2H), 3.44 (s, 3H), 3.73 (dd,
J = 5.4, 3.9 Hz, 2H), 4.04 (dd, J = 5.4, 3.7 Hz, 2H), 6.31–6.41 (m, 1H),
6.44 (d, J = 2.3 Hz, 1H), 6.77 (d, J = 8.5 Hz, 1H), 7.50 (t, J = 7.5 Hz, 2H),
7.57–7.68 (m, 1H), 7.81–7.87 (m, 2H), 8.09 (d, J = 2.3 Hz, 1H), 8.46 (d,
J = 1.1 Hz, 1H), 9.42 (br s, 1H). Anal. Calcd for C24H22ClF3N2O6S: C,
51.57; H, 3.97; N, 5.01. Found: C, 51.58; H, 3.85; N, 4.98.
C
24H28ClF3N2O6Sꢀ0.10hexane: C, 51.51; H, 5.17; N, 4.88. Found: C,
51.64; H, 5.23; N, 4.84.
5.1.1.44. 3-[2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}-
4-(2-methoxyethoxy)phenyl]-2-methyl-N-(pentylsulfonyl)pro-
panamide (8h).
Compound 8h (white crystals) was prepared
from 34f and pentane-1-sulfonamide in 57% yield following a sim-
ilar procedure to provide 8f. Mp 136.5–138.0 °C (EtOAc/hexane).
1H NMR (CDCl3): d 0.85–0.94 (m, 3H), 1.22 (d, J = 5.8 Hz, 3H),
1.25–1.40 (m, 4H), 1.48–1.72 (m, 2H), 2.54–2.66 (m, 2H), 2.86
(ddd, J = 13.8, 10.3, 5.5 Hz, 1H), 2.98–3.12 (m, 1H), 3.21 (ddd,
J = 14.0, 10.4, 5.6 Hz, 1H), 3.41 (s, 3H), 3.61–3.77 (m, 2H), 3.97–
4.07 (m, 2H), 6.43 (d, J = 2.4 Hz, 1H), 6.75 (dd, J = 8.4, 2.5 Hz, 1H),
7.14 (d, J = 8.5 Hz, 1H), 8.11 (d, J = 1.9 Hz, 1H), 8.42 (dd, J = 2.1,
0.9 Hz, 1H), 9.53 (s, 1H). Anal. Calcd for C24H30ClF3N2O6S: C,
50.84; H, 5.33; N, 4.94. Found: C, 50.88; H, 5.26; N, 4.93.
5.1.1.41. N-[(4-Chlorophenyl)sulfonyl]-3-[2-{[3-chloro-5-(tri-
fluoromethyl)pyridin-2-yl]oxy}-4-(2-methoxyethoxy)phenyl]-
propanamide (8e).
0.272 mmol) in THF (2 mL) was added thionyl chloride (50
0.695 mmol), followed by DMF (10 L, 0.130 mmol) at 0 °C. After
To a stirred solution of 34a (114 mg,
l
L,
l
being stirred for 2 h at the same temperature, the mixture was
concentrated in vacuo, and the residue was dissolved into THF
(2 mL). To the solution was added 4-chlorobenzenesulfonamide
(60.0 mg, 0.313 mmol), followed by DIPEA (50
l
L, 0.292 mmol)
5.1.1.45. (2E)-3-(2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-
yl]oxy}-4-isopropoxyphenyl)-N-(pentylsulfonyl)acrylamide
and DMAP (39.0 mg, 0.320 mmol) at room temperature. After
being stirred for 3 h, the reaction was quenched with sat. NH4Cl
and extracted with EtOAc and the organic layer was washed with
brine, dried over MgSO4, filtered and concentrated under re-
duced pressure. The residual solid was purified by silica gel chro-
matography (hexane-EtOAc, 9:1 to 3:2) to give a white solid,
which was recrystallized from EtOAc/hexane to give 8e
(88.0 mg, 54%) as white crystals. Mp 140.0–141.5 °C. 1H NMR
(CDCl3): d 2.47 (t, J = 7.1 Hz, 2H), 2.87 (t, J = 7.2 Hz, 2H), 3.45 (s,
3H), 3.71–3.76 (m, 2H), 3.99–4.11 (m, 2H), 6.17–6.52 (m, 2H),
6.75 (d, J = 8.7 Hz, 1H), 7.47 (d, J = 8.7 Hz, 2H), 7.75 (d,
J = 8.7 Hz, 2H), 8.11 (s, 1H), 8.48 (s, 1H). Anal. Calcd for
(8i).
Compound 8i (white fine needles) was prepared from
34g and pentane-1-sulfonamide in 35% yield following a similar
procedure to provide 8a. Mp 142–144 °C (EtOAc/hexane). 1H
NMR (CDCl3): d 0.89 (t, J = 7.1 Hz, 3H), 1.19–1.47 (m, 10H), 1.72–
2.02 (m, 2H), 3.27–3.54 (m, 2H), 4.33–4.66 (m, 1H), 6.36 (d,
J = 15.6 Hz, 1H), 6.64 (d, J = 2.4 Hz, 1H), 6.85 (dd, J = 8.9, 2.6 Hz,
1H), 7.59 (d, J = 8.9 Hz, 1H), 7.79 (d, J = 15.6 Hz, 1H), 8.03 (d,
J = 2.3 Hz, 1H), 8.26 (s, 1H). Anal. Calcd for C23H26ClF3N2O5S: C,
51.64; H, 4.90; N, 5.24. Found: C, 51.91; H, 4.99; N, 5.06.
5.1.1.46. (2E)-3-{2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-
yl]oxy}-4-[2-(cyclopropyloxy)ethoxy]phenyl}-N-(pentylsulfo-
C
24H21Cl2F3N2O6S: C, 48.58; H, 3.57; N, 4.72. Found: C, 48.33;
H, 3.69; N, 4.55.
nyl)acrylamide (8j).
Compound 8j (white crystals) was pre-
pared from 34h and pentane-1-sulfonamide in 42% yield following
a similar procedure to provide 8f. Mp 104.6–106.5 °C (EtOAc/hex-
ane). 1H NMR (CDCl3): d 0.45–0.56 (m, 2H), 0.57–0.65 (m, 2H), 0.89
(t, J = 7.1 Hz, 3H), 1.21–1.47 (m, 4H), 1.83 (tt, J = 7.8, 7.2 Hz, 2H),
3.38 (tt, J = 5.9, 3.0 Hz, 1H), 3.43–3.51 (m, 2H), 3.85 (dd, J = 5.5,
4.0 Hz, 2H), 4.08–4.16 (m, 2H), 6.37 (d, J = 15.5 Hz, 1H), 6.69 (d,
J = 2.7 Hz, 1H), 6.90 (dd, J = 8.9, 2.5 Hz, 1H), 7.60 (d, J = 9.1 Hz,
1H), 7.74 (s, 1H), 7.79 (d, J = 15.9 Hz, 1H), 8.03 (d, J = 2.3 Hz, 1H),
8.25 (dd, J = 2.1, 0.9 Hz, 1H). Anal. Calcd for C25H28ClF3N2O6S: C,
52.04; H, 4.89; N, 4.85. Found: C, 51.96; H, 4.87; N, 4.84.
5.1.1.42. (2E)-3-[2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-
yl]oxy}-4-(2-methoxyethoxy)phenyl]-N-(pentylsulfonyl)acryl-
amide (8f).
To a stirred solution of 34d (1.00 g, 2.39 mmol),
WSC-HCl (424 mg, 2.80 mmol) and DMAP (370 mg, 3.03 mmol) in
MeCN was added 1-ethyl-3-(3-dimethylaminopropyl)carbodiim-
ide (400 mg, 2.58 mmol) at 0 °C, and the mixture was allowed
to warm to room temperature. After being stirred overnight at
the same temperature, the reaction was quenched with 1 M HCl
and extracted with EtOAc. The organic layer was washed with

3348
K. Rikimaru et al. / Bioorg. Med. Chem. 20 (2012) 3332–3358
5.1.1.47. (2E)-3-[2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-
yl]oxy}-4-(3-methoxypropoxy)phenyl]-N-(pentylsulfonyl)acryl-
urated brine, dried over MgSO4, and concentrated. The obtained so-
lid was recrystallized from EtOAc to give 8o (418 mg, 60%) as
colorless crystals. Mp 180–181 °C. 1H NMR (CDCl3): d 0.85–0.94
(m, 3H), 1.20–1.47 (m, 4H), 1.75–1.90 (m, 2H), 2.24 (s, 3H), 2.93
(t, J = 6.2 Hz, 2H), 3.41–3.52 (m, 2H), 4.25 (t, J = 6.2 Hz, 2H), 6.38
(d, J = 15.6 Hz, 1H), 6.67 (d, J = 2.4 Hz, 1H), 6.87 (dd, J = 8.8,
2.4 Hz, 1H), 7.60 (d, J = 8.8 Hz, 1H), 7.79 (d, J = 15.6 Hz, 1H), 7.93
(br s, 1H), 8.03 (d, J = 2.1 Hz, 1H), 8.23–8.26 (m, 1H). Anal. Calcd
for C24H26ClF3N2O6S: C, 51.20; H, 4.65; N, 4.98. Found: C, 51.08;
H, 4.60; N, 4.91.
amide (8k).
Compound 8k (white crystals) was prepared
from 34i and pentane-1-sulfonamide in 26% yield following a sim-
ilar procedure to provide 8f. Mp 116.5–118.0 °C (EtOAc/hexane).
1H NMR (CDCl3): d 0.82–0.94 (m, 3H), 1.25–1.48 (m, 4H), 1.76–
1.92 (m, 2H), 2.05 (tt, J = 6.1 Hz, 2H), 3.34 (s, 3H), 3.43–3.50 (m,
2H), 3.54 (t, J = 6.0 Hz, 2H), 4.08 (t, J = 6.2 Hz, 2H), 6.37 (d,
J = 15.6 Hz, 1H), 6.68 (d, J = 2.4 Hz, 1H), 6.89 (dd, J = 8.9, 2.5 Hz,
1H), 7.61 (d, J = 8.7 Hz, 1H), 7.73 (br s, 1H), 7.79 (d, J = 15.4 Hz,
1H), 8.04 (d, J = 2.1 Hz, 1H), 8.13–8.32 (m, 1H). Anal. Calcd for
C
24H28ClF3N2O6S: C, 51.02; H, 5.00; N, 4.96. Found: C, 51.06; H,
5.1.1.52. (2E)-3-{2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-
yl]oxy}-4-[3-(methylsulfonyl)propoxy]phenyl}-N-(pentylsulfo-
5.01; N, 4.77.
nyl)acrylamide (8p).
Compound 8p (white crystals) was pre-
5.1.1.48. (2E)-3-(2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-
yl]oxy}-4-{2-[(triisopropylsilyl)oxy]ethoxy}phenyl)-N-(pent-
pared from 34l and pentane-1-sulfonamide in 56% yield following
a similar procedure to provide 8f. Mp 194–196 °C (EtOH/H2O). 1H
NMR (DMSO-d6): d 0.72–0.90 (m, 3H), 1.11–1.42 (m, 4H), 1.47–
1.74 (m, 2H), 2.01–2.24 (m, 2H), 3.01 (s, 3H), 3.21–3.29 (m, 2H),
3.29–3.32 (m, 2H), 4.13 (t, J = 6.3 Hz, 2H), 6.56 (d, J = 15.8 Hz,
1H), 6.92–7.15 (m, 2H), 7.53 (d, J = 15.1 Hz, 1H), 7.71 (d,
J = 8.5 Hz, 1H), 8.45–8.55 (m, 1H), 8.66 (d, J = 2.1 Hz, 1H), 11.78
(s, 1H). Anal. Calcd for C24H28ClF3N2O7S2: C, 47.02; H, 4.60; N,
4.57. Found: C, 47.18; H, 4.48; N, 4.43.
ylsulfonyl)acrylamide (8l).
Compound 8l (a white powder)
was prepared from 34j and pentane-1-sulfonamide in 46% yield
following a similar procedure to provide 8f. Mp 106–108 °C (IPE/
hexane). 1H NMR (CDCl3): d 0.89 (t, J = 7.2 Hz, 3H), 0.98–1.17 (m,
21H), 1.21–1.49 (m, 4H), 1.70–1.92 (m, 2H), 3.35–3.56 (m, 2H),
3.91–4.19 (m, 4H), 6.37 (d, J = 15.8 Hz, 1H), 6.70 (d, J = 2.5 Hz,
1H), 6.90 (dd, J = 8.7, 2.5 Hz, 1H), 7.60 (d, J = 8.9 Hz, 1H), 7.72–
7.83 (m, 2H), 8.03 (d, J = 2.1 Hz, 1H), 8.25 (dd, J = 2.0, 0.9 Hz, 1H).
Anal. Calcd for C31H44ClF3N2O6SSi: C, 53.71; H, 6.40; N, 4.04.
Found: C, 53.65; H, 6.40; N, 4.07.
5.1.1.53. (2E)-3-[2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-
yl]oxy}-4-(3-cyanopropoxy)phenyl]-N-(pentylsulfonyl)acrylam-
ide (8q).
Compound 8q (colorless crystals) was prepared from
5.1.1.49.
yl]oxy}-4-(2-hydroxy-2-methylpropoxy)phenyl]-N-(pent-
ylsulfonyl)acrylamide (8m). To solution of 8l (4.40 g,
(2E)-3-[2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-
34m in 26% yield following a similar procedure to provide 8f. Mp
165–166 °C (EtOAc). 1H NMR (CDCl3): d 0.83–0.94 (m, 3H), 1.21–
1.47 (m, 4H), 1.75–1.90 (m, 2H), 2.09–2.22 (m, 2H), 2.59 (t,
J = 7.0 Hz, 2H), 3.41–3.52 (m, 2H), 4.11 (t, J = 5.7 Hz, 2H), 6.38 (d,
J = 15.8 Hz, 1H), 6.69 (d, J = 2.6 Hz, 1H), 6.88 (dd, J = 8.9, 2.6 Hz,
1H), 7.62 (d, J = 8.9 Hz, 1H), 7.79 (d, J = 15.8 Hz, 1H), 8.04 (d,
J = 2.1 Hz, 1H), 8.25 (d, J = 1.1 Hz, 1H). Anal. Calcd for
a
6.35 mmol) in THF (6 mL) was added 1 M TBAF in THF (9.52 mL,
9.52 mmol) at room temperature, and the mixture was stirred at
50 °C for 30 min. The mixture was diluted with water and ex-
tracted with EtOAc. The organic layer was washed with brine, dried
over MgSO4, filtrated and concentrated. The obtained residue was
subjected to silica gel column chromatography (hexane-EtOAc,
20:1 to 4:1) and the obtained residue was recrystallized from
IPE/hexane to give 8m (1.03 g, 30%) as a white powder. Mp
112.5–112.8 °C. 1H NMR (CDCl3): d 0.88 (t, J = 7.2 Hz, 3H), 1.23–
1.47 (m, 4H), 1.74–1.90 (m, 2H), 3.38–3.55 (m, 2H), 3.88–4.03
(m, 2H), 4.04–4.19 (m, 2H), 6.37 (d, J = 15.6 Hz, 1H), 6.71 (d,
J = 2.5 Hz, 1H), 6.89 (dd, J = 8.9, 2.5 Hz, 1H), 7.60 (d, J = 8.9 Hz,
1H), 7.79 (d, J = 15.6 Hz, 1H), 8.03 (d, J = 2.1 Hz, 1H), 8.25 (d,
C24H25ClF3N3O5S: C, 51.48; H, 4.50; N, 7.50. Found: C, 51.61; H,
4.55; N, 7.51.
5.1.1.54. Benzyl [(pentylamino)sulfonyl]carbamate (35)26
.
To
a stirred solution of benzyl alcohol (3.06 g, 28.3 mmol) in DCM
(150 mL) was added chlorosulfonyl isocyanate (2.55 mL,
29.3 mmol) at 0 °C and after 30 min, pyridine (8.00 mL, 99.1 mmol)
was added. After being stirred at the same temperature for addi-
tional 1 h, pentylamine (16.0 mL, 138 mmol) was added to the
mixture, which was allowed to warm to room temperature. After
being stirred overnight, the reaction was quenched with 1 M HCl
and diluted with EtOAc and the organic layer was washed with
water, 1 M HCl, sat. NaHCO3 and brine, dried over MgSO4, filtered
and evaporated under reduced pressure. The residual solid was
recrystallized from EtOAc/hexane to give 35 (8,18 g, 96%) as white
crystals. Mp 142.5–143.0 °C (EtOAc/hexane). 1H NMR (CDCl3): d
ppm 0.85–0.92 (m, 3H), 1.25–1.34 (m, 4H), 1.46–1.63 (m, 2H),
2.79–3.14 (m, 2H), 5.07 (s, 1H), 5.19 (s, 2H), 7.26 (s, 1H), 7.28–
7.54 (m, 5H). Anal. Calcd for C13H20N2O4S: C, 51.98; H, 6.71; N,
9.33. Found: C, 52.16; H, 6.78; N, 9.46.
J = 1.1 Hz, 1H). Anal. Calcd for
48.40; H, 4.62; N, 5.13. Found: C, 48.71; H, 4.78; N, 5.13.
C
22H24ClF3N2O6Sꢀ0.50H2O: C,
5.1.1.50. (2E)-3-{2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-
yl]oxy}-4-[2-(2-methyl-1,3-dioxolan-2-yl)ethoxy]phenyl}-N-
(pentylsulfonyl)acrylamide (8n).
Compound 8n (colorless
crystals) was prepared from 34k in 52% yield following a similar
procedure to provide 8f. Mp 90–92 °C (EtOAc/hexane). 1H NMR
(CDCl3): d 0.85–0.93 (m, 3H), 1.22–1.46 (m, 7H), 1.76–1.89 (m,
2H), 2.18 (t, J = 7.1 Hz, 2H), 3.42–3.51 (m, 2H), 3.91–4.00 (m, 4H),
4.12 (t, J = 7.1 Hz, 2H), 6.37 (d, J = 15.6 Hz, 1H), 6.67 (d, J = 2.5 Hz,
1H), 6.88 (dd, J = 8.9, 2.5 Hz, 1H), 7.60 (d, J = 8.9 Hz, 1H), 7.78 (d,
J = 15.6 Hz, 1H), 8.03 (d, J = 2.3 Hz, 1H), 8.26 (d, J = 0.9 Hz, 1H).
Anal. Calcd for C26H30ClF3N2O7S: C, 51.44; H, 4.98; N, 4.61. Found:
C, 51.54; H, 5.02; N, 4.41.
5.1.1.55. N-Pentylsulfamide (36).
A stirred solution of 35
(5.83 g, 19.4 mmol) in THF (50 mL) and EtOH (50 mL) was hydro-
genated under atmospheric pressure with 10% Pd/C (wet, 3.11 g,
2.92 mmol) at room temperature for 2 h. The catalyst was re-
moved by filtration and the filtrate was concentrated in vacuo.
The residual solid was recrystallized from EtOAc/IPE to give 36
(3.15 mg, 98%) as white mica crystals. Mp 60–64 °C. 1H NMR
(CDCl3): d ppm 0.78–1.00 (m, 3H), 1.17–1.44 (m, 4H), 1.51–1.67
(m, 2H), 3.13 (t, J = 7.2 Hz, 1H), 4.52 (br s, 3H). Anal. Calcd for
C5H14N2O2S: C, 36.12; H, 8.49; N, 16.85. Found: C, 36.04; H,
8.36; N, 16.93.
5.1.1.51. (2E)-3-[2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-
yl]oxy}-4-(3-oxobutoxy)phenyl]-N-(pentylsulfonyl)acrylamide
(8o).
A mixture of 8n (750 mg), 1 M HCl (5 mL), and THF
(15 mL) was stirred at 60 °C for 1 h. After being cooled to room
temperature, the mixture was concentrated under reduced pres-
sure. Water was added to the obtained residue, and the mixture
was extracted with EtOAc. The organic layer was washed with sat-

K. Rikimaru et al. / Bioorg. Med. Chem. 20 (2012) 3332–3358
3349
5.1.1.56. 3-[2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}-
4-(2-methoxyethoxy)phenyl]-N-[(pentylamino)sulfonyl]pro-
6.77 (dd, J = 8.7, 2.4 Hz, 1H), 6.96 (d, J = 8.7 Hz, 1H), 7.45 (d,
J = 8.7 Hz, 1H), 7.59 (d, J = 8.7 Hz, 1H), 7.75 (s, 1H), 7.85 (d,
J = 16.2 Hz, 1H).
panamide (8r).
Compound 8r (white crystals) was prepared
from 34d and 36 in 13% yield following a similar procedure to pro-
vide 8f. Mp 153.0–154.5 °C (EtOH/H2O). 1H NMR (CDCl3): d 0.85–
0.93 (m, 3H), 1.20–1.37 (m, 4H), 1.47 (tt, J = 7.3, 7.2 Hz, 2H), 2.57
(t, J = 7.2 Hz, 2H), 2.71 (q, J = 6.8 Hz, 2H), 2.92 (t, J = 7.3 Hz, 2H),
3.42 (s, 3H), 3.68–3.74 (m, 2H), 4.03–4.08 (m, 2H), 4.99 (t,
J = 6.3 Hz, 1H), 6.55 (d, J = 2.4 Hz, 1H), 6.78 (dd, J = 8.5, 2.4 Hz,
1H), 7.19 (d, J = 8.5 Hz, 1H), 8.07 (d, J = 2.3 Hz, 1H), 8.35 (dd,
J = 2.0, 0.8 Hz, 1H), 8.76 (s, 1H). Anal. Calcd for C23H29ClF3N3O6S:
C, 48.63; H, 5.15; N, 7.40. Found: C, 48.66; H, 4.95; N, 7.30.
5.1.1.62. Ethyl (2E)-3-[4-(2-methoxyethoxy)-2-{[5-(trifluoro-
methyl)pyridin-2-yl]oxy}phenyl]acrylate (12b).
Compound
12b (a colorless oil) was prepared from 10 in 88% yield following
a similar procedure to provide 5a. 1H NMR (CDCl3): d 1.27 (t,
J = 7.2 Hz, 3H), 3.43 (s, 3H), 3.71–3.76 (m, 2H), 4.08–4.14 (m, 2H),
4.19 (q, J = 7.2 Hz, 2H), 6.35 (d, J = 16.2 Hz, 1H), 6.67 (d, J = 2.6 Hz,
1H), 6.88 (dd, J = 8.7, 2.6 Hz, 1H), 7.08 (d, J = 8.7 Hz, 1H), 7.63 (d,
J = 8.7 Hz, 1H), 7.72 (d, J = 16.2 Hz, 1H), 7.93 (dd, J = 8.7, 2.6 Hz,
1H), 8.42 (s, 1H).
5.1.1.57.
(9).
2-Hydroxy-4-(2-methoxyethoxy)benzaldehyde
Compound 9 (white fine needles) was prepared from 3
5.1.1.63. Ethyl (2E)-3-{2-[(3-chloropyridin-2-yl)oxy]-4-(2-
in 35% yield following a similar procedure to provide 7a using
DEAD and triphenylphosphine instead of ADDP and tributylphos-
phine. Mp 64.5–65.5 °C (EtOAc/hexane). 1H NMR (CDCl3): d 3.45
(s, 3H), 3.70–3.82 (m, 2H), 4.10–4.32 (m, 2H), 6.44 (d, J = 2.3 Hz,
1H), 6.58 (dd, J = 8.7, 2.3 Hz, 1H), 7.43 (d, J = 8.7 Hz, 1H), 9.72 (s,
1H), 11.47 (s, 1H). Anal. Calcd for C10H12O4: C, 61.22; H, 6.16.
Found: C, 61.23; H, 6.23.
methoxyethoxy)phenyl}acrylate (12c).
Compound 12c
(colorless crystals) was prepared from 11a in 96% yield fol-
lowing a similar procedure to provide 6a. 1H NMR (CDCl3): d
1.28 (t, J = 7.2 Hz, 3H), 3.42 (s, 3H), 3.71–3.75 (m, 2H), 4.09–
4.13 (m, 2H), 4.19 (q, J = 7.2 Hz, 2H), 6.38 (d, J = 16.0 Hz, 1H),
6.67 (d, J = 2.6 Hz, 1H), 6.84 (dd, J = 8.8, 2.6 Hz, 1H), 6.99 (dd,
J = 7.7, 4.9 Hz, 1H), 7.60 (d, J = 8.8 Hz, 1H), 7.73–7.84 (m,
2H), 8.01 (dd, J = 4.9, 1.7 Hz, 1H).
5.1.1.58. Ethyl (2E)-3-[2-hydroxy-4-(2-methoxyethoxy)-
phenyl]acrylate (10)
.
To a stirred solution of 9 (14.6 g,
5.1.1.64. Ethyl (2E)-3-[2-[(3,5-dichloropyridin-2-yl)oxy]-4-(2-
74.4 mmol) in DCM (60 mL) was added a solution of (carbeth-
oxymethylene)triphenylphosphorane (28.6 g, 74.0 mmol) in DCM
(100 mL) at 0 °C over 10 min, and the mixture was allowed to
warm to room temperature. After being stirred at room tempera-
ture for 1 h, the reaction was quenched with AcOH (2 mL). The
reaction mixture was concentrated under reduced pressure, and
the residue was extracted with EtOAc. The organic layer was
washed with brine, dried over MgSO4, and concentrated. The ob-
tained residue was subjected to silica gel chromatography (hex-
ane-EtOAc, 3:2) to give a white solid, which was recrystallized
from EtOAc/hexane to give 10 (17.7 g, 89%) as colorless crystals.
1H NMR (CDCl3): d 1.33 (t, J = 7.2 Hz, 3H), 3.47 (s, 3H), 3.76–3.80
(m, 2H), 4.10–4.14 (m, 2H), 4.26 (q, J = 7.2 Hz, 2H), 6.44–6.52 (m,
3H), 7.06 (s, 1H), 7.37 (d, J = 9.3 Hz, 1H), 7.92 (d, J = 16.2 Hz, 1H).
methoxyethoxy)phenyl]acrylate (12d).
Compound 12d (col-
orless crystals) was prepared from 10 in 72% yield following a sim-
ilar procedure to provide 5a. Mp 70.7–71.3 °C (EtOAc/hexane). 1H
NMR (CDCl3): d 1.29 (t, J = 7.2 Hz, 3H), 3.43 (s, 3H), 3.71–3.76 (m,
2H), 4.10–4.14 (m, 2H), 4.20 (q, J = 7.2 Hz, 2H), 6.36 (d,
J = 16.1 Hz, 1H), 6.66 (d, J = 2.7 Hz, 1H), 6.85 (dd, J = 8.4, 2.7 Hz,
1H), 7.61 (d, J = 8.7 Hz, 1H), 7.74 (d, J = 16.1 Hz, 1H), 7.80 (s, 1H),
7.94 (s, 1H). Anal. Calcd for C19H19Cl2NO5: C, 55.35; H, 4.65; N,
3.40. Found: C, 55.44; H, 4.83; N, 3.30.
5.1.1.65. Ethyl (2E)-3-{4-(2-methoxyethoxy)-2-[(3-methyl-5-
nitropyridin-2-yl)oxy]phenyl}acrylate (16e).
Compound
12e (pale-yellow crystals) was prepared from 10 and 2-chloro-
5-nitro-3-picoline in 98% yield following a similar procedure to
provide 5a. 1H NMR (CDCl3): d 1.27 (t, J = 7.1 Hz, 3H), 2.52 (s,
3H), 3.44 (s, 3H), 3.73–3.76 (m, 2H), 4.12–4.15 (m, 2H), 4.18 (q,
J = 7.1 Hz, 2H), 6.32 (d, J = 16.2 Hz, 1H), 6.68 (d, J = 2.4 Hz, 1H),
6.90 (dd, J = 8.7, 2.4 Hz, 1H), 7.63 (d, J = 8.7 Hz, 1H), 7.64 (d,
J = 16.2 Hz, 1H), 8.35 (d, J = 1.8 Hz, 1H), 8.81 (d, J = 1.8 Hz, 1H).
5.1.1.59. 2-[(3-Chloropyridin-2-yl)oxy]-4-(2-methoxyeth-
oxy)benzaldehyde (11a).
Compound 11a (colorless crystals)
was prepared from 9 in 49% yield following a similar procedure
to provide 5a. 1H NMR (CDCl3): d 3.43 (s, 3H), 3.73–3.77 (m, 2H),
4.15–4.19 (m, 2H), 6.72 (d, J = 2.3 Hz, 1H), 6.90 (dd, J = 8.7, 2.3 Hz,
1H), 7.03 (dd, J = 8.0, 4.9 Hz, 1H), 7.81 (dd, J = 8.0, 1.7 Hz, 1H),
7.92 (d, J = 8.7 Hz, 1H), 8.02 (dd, J = 4.9, 1.7 Hz, 1H), 10.11 (s, 1H).
5.1.1.66. Ethyl (2E)-3-{2-[(5-amino-3-methylpyridin-2-yl)oxy]-
4-(2-methoxyethoxy)phenyl}acrylate (12f).
To a suspension
of H2O (5 mL) and zinc powder (379 mg, 5.80 mmol) was added a
solution of 12e (455 mg, 1.13 mmol) in AcOH (5 mL), and the mix-
ture was stirred at room temperature for 2 h. The reaction mixture
was concentrated under reduced pressure, the obtained residue
was basified with 8 M NaOH, and the mixture was extracted with
EtOAc. The organic layer was washed with brine, dried over MgSO4,
and concentrated. The obtained residue was subjected to silica gel
column chromatography (hexane-EtOAc, 1:1) to give 12f (307 mg,
73%) as brown crystals. 1H NMR (CDCl3): d 1.30 (t, J = 7.2 Hz, 3H),
2.23 (s, 3H), 3.41 (s, 3H), 3.51 (s, 2H), 3.67–3.71 (m, 2H), 4.03–
4.07 (m, 2H), 4.21 (q, J = 7.2 Hz, 2H), 6.38 (s, 1H), 6.41 (d,
J = 15.9 Hz, 1H), 6.67 (dd, J = 8.7, 2.4 Hz, 1H), 6.96 (d, J = 2.4 Hz,
1H), 7.52–7.55 (m, 2H), 7.93 (d, J = 15.9 Hz, 1H).
5.1.1.60. 2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}-4-
(2-methoxyethoxy)benzaldehyde (11b).
Compound 11b
(white prisms) was prepared from 9 and 2,3-dichloro-5-(trifluoro-
methyl)pyridine in 60% yield following a similar procedure to pro-
vide 5a. Mp 80.5–81.0 °C (EtOAc/hexane). 1H NMR (CDCl3): d 3.45
(s, 3H), 3.66–3.84 (m, 2H), 4.10–4.34 (m, 2H), 6.77 (d, J = 2.3 Hz,
1H), 6.97 (dd, J = 8.7, 2.4 Hz, 1H), 7.91 (d, J = 8.9 Hz, 1H), 8.03 (d,
J = 2.3 Hz, 1H), 8.23 (d, J = 1.1 Hz, 1H), 9.98 (s, 1H). Anal. Calcd for
C16H13NO4ClF3: C, 51.15; H, 3.49; N, 3.73. Found: C, 51.18; H,
3.48; N, 3.64.
5.1.1.61. Ethyl (2E)-3-{2-[2-chloro-4-(trifluoromethyl)phen-
oxy]-4-(2-methoxyethoxy)phenyl}acrylate
(12a).
Com-
pound 12a (colorless crystals) was prepared from 10 and 3-
chloro-4-fluorobenzotrifluoride in 88% yield following a similar
procedure to provide 5a. 1H NMR (CDCl3): d 1.30 (t, J = 7.2 Hz,
3H), 3.41 (s, 3H), 3.69–3.72 (m, 2H), 4.05–4.09 (m, 2H), 4.22 (q,
J = 7.2 Hz, 2H), 6.36 (d, J = 2.4 Hz, 1H), 6.43 (d, J = 16.2 Hz, 1H),
5.1.1.67. Ethyl (2E)-3-[2-({5-[(tert-butoxycarbonyl)amino]-3-
methylpyridin-2-yl}oxy)-4-(2-methoxyethoxy)phenyl]acrylate
(12g).
To a solution of 12f (300 mg, 0.806 mmol) in THF
(10 mL) was added di-tert-butyl dicarbonate (880 mg, 4.03 mmol),
and the mixture was stirred at 60 °C for 11 h. The reaction mixture

3350
K. Rikimaru et al. / Bioorg. Med. Chem. 20 (2012) 3332–3358
was concentrated under reduced pressure, the obtained residue
was subjected to silica gel column chromatography, (hexane-
EtOAc, 2:1) to give 12g (351 mg, 92%) as colorless crystals. 1H
NMR (CDCl3): d 1.29 (t, J = 7.2 Hz, 3H), 1.52 (s, 9H), 2.35 (s, 3H),
3.41 (s, 3H), 3.69–3.72 (m, 2H), 4.05–4.08 (m, 2H), 4.20 (q,
J = 7.2 Hz, 2H), 6.36 (d, J = 15.9 Hz, 1H), 6.34–6.40 (m,1H), 6.49 (d,
J = 2.7 Hz, 1H), 6.74 (dd, J = 8.7, 2.7 Hz, 1H), 7.57 (d, J = 8.7 Hz,
1H), 7.78–7.79 (m, 1H), 7.85 (d, J = 15.9 Hz, 1H), 7.93 (s, 1H).
5.1.1.73. (2E)-3-[2-[2-Chloro-4-(trifluoromethyl)phenoxy]-
4-(2-methoxyethoxy)phenyl]-N-(pentylsulfonyl)acrylamide
(13a).
Compound 13a (colorless crystals) was prepared from
37a and pentane-1-sulfonamide in 30% yield following a similar
procedure to provide 8f. Mp 134.1–135.1 °C (EtOAc/hexane). 1H
NMR (CDCl3): d 0.89 (t, J = 7.1 Hz, 3H), 1.30–1.45 (m, 4H), 1.77–
1.90 (m, 2H), 3.41 (s, 3H), 3.42–3.52 (m, 2H), 3.69–3.74 (m, 2H),
4.05–4.12 (m, 2H), 6.33 (s, 1H), 6.49 (d, J = 15.7 Hz, 1H), 6.74–
6.79 (m, 1H), 7.02 (d, J = 8.7 Hz, 1H), 7.51 (d, J = 8.7 Hz, 1H), 7.56
(d, J = 8.7 Hz, 1H), 7.72 (s, 1H), 7.77 (s, 1H), 7.92 (d, J = 15.7 Hz,
1H). Anal. Calcd for C24H27ClF3NO6S: C, 52.41; H, 4.95; N, 2.55.
Found: C, 52.34; H, 4.82; N, 2.41.
5.1.1.68. (2E)-3-[2-[2-Chloro-4-(trifluoromethyl)phenoxy]-4-(2-
methoxyethoxy)phenyl]acrylic acid (37a).
Compound 37a
(colorless crystals) was prepared from 12a in 97% yield following
a similar procedure to provide 7a. Mp 165.6–166.0 °C (EtOAc/hex-
ane). 1H NMR (DMSO-d6): d 3.27 (s, 3H), 3.60–3.64 (m, 2H), 4.10–
4.14 (m, 2H), 6.47 (d, J = 16.2 Hz, 1H), 6.64 (d, J = 2.4 Hz, 1H),
6.94 (dd, J = 8.7, 2.4 Hz, 1H), 7.05 (d, J = 8.7 Hz, 1H), 7.59 (d,
J = 16.2 Hz, 1H), 7.69 (d, J = 8.7 Hz, 1H), 7.89 (d, J = 8.7 Hz, 1H),
8.07 (s, 1H), 12.34 (s, 1H). Anal. Calcd for C19H16ClF3O5: C, 54.75;
H, 3.87. Found: C, 54.80; H, 3.79.
5.1.1.74. Potassium [(2E)-3-(4-(2-methoxyethoxy)-2-{[5-(tri-
fluoromethyl)pyridin-2-yl]oxy}phenyl)acryl](pentylsulfo-
nyl)azanide
(13b).
(2E)-3-(4-(2-methoxyethoxy)-2-{[5-
(trifluoromethyl)pyridin-2-yl]oxy}phenyl)-N-(pentylsulfonyl)acryl
amide (a colorless amorphous solid) was prepared from 37b and
pentane-1-sulfonamide in 91% yield following a similar procedure
to provide 13c (described below). 1H NMR (CDCl3): d 0.88 (t,
J = 7.0 Hz, 3H), 1.25–1.46 (m, 4H), 1.74–1.89 (m, 2H), 3.43 (s, 3H),
3.43–3.45 (m, 2H), 3.71–3.79 (m, 2H), 4.10–4.16 (m, 2H), 6.38 (d,
J = 15.6 Hz, 1H), 6.68 (d, J = 2.4 Hz, 1H), 6.88 (dd, J = 8.7, 2.4 Hz,
1H), 7.09 (d, J = 8.7 Hz, 1H), 7.59 (d, J = 8.7 Hz, 1H), 7.81 (d,
J = 15.6 Hz, 1H), 7.95 (dd, J = 8.7, 2.4 Hz, 1H), 8.15 (s, 1H), 8.42 (s,
1H). Anal. Calcd for C23H27F3N2O6S: C, 53.48; H, 5.27; N, 5.42.
Found: C, 53.27; H, 5.30; N, 5.34.
To a solution of (2E)-3-(4-(2-methoxyethoxy)-2-{[5-(trifluoro-
methyl)pyridin-2-yl]oxy}phenyl)-N-(pentylsulfonyl)acrylamide
(259 mg, 0.501 mmol) in MeOH (4 mL) was added a solution of
KHCO3 (50 mg, 0.499 mmol) in H2O (0.5 mL), and the mixture
was stirred at room temperature for 90 min. The reaction mixture
was concentrated under reduced pressure, and the obtained
crude product were recrystallized from EtOH/hexane to give
13b (254 mg, 91%) as colorless crystals. Mp 153.0–155.2 °C. 1H
NMR (DMSO-d6): d 0.77–0.84 (m, 3H), 1.16–1.29 (m, 4H), 1.40–
1.56 (m, 2H), 2.86–2.94 (m, 2H), 3.29 (s, 3H), 3.60–3.66 (m,
2H), 4.07–4.12 (m, 2H), 6.31 (d, J = 15.9 Hz, 1H), 6.77 (d,
J = 2.3 Hz, 1H), 6.89 (dd, J = 8.7, 2.3 Hz, 1H), 7.17 (d, J = 15.9 Hz,
1H), 7.27 (d, J = 8.7 Hz, 1H), 7.69 (d, J = 8.7 Hz, 1H), 8.24 (dd,
J = 8.7, 2.7 Hz, 1H), 8.55 (s, 1H). Anal. Calcd for C23H26F3KN2
O6Sꢀ0.5H2O: C, 49.01; H, 4.83; N, 4.97. Found: C, 49.27; H, 4.79;
N, 4.96.
5.1.1.69. (2E)-3-(4-(2-Methoxyethoxy)-2-{[5-(trifluoromethyl)-
pyridin-2-yl]oxy}phenyl)acrylic acid (37b).
Compound 37b
(colorless crystals) was prepared from 12b in 96% yield following
a similar procedure to provide 7a. Mp 179.5–179.8 °C (EtOH/hex-
ane). 1H NMR (DMSO-d6): d 3.29 (s, 3H), 3.60–3.66 (m, 2H), 4.10–
4.16 (m, 2H), 6.41 (d, J = 15.9 Hz, 1H), 6.86 (d, J = 2.7 Hz, 1H),
6.94 (dd, J = 8.7, 2.7 Hz, 1H), 7.34 (d, J = 8.7 Hz, 1H), 7.49 (d,
J = 15.9 Hz, 1H), 7.86 (d, J = 8.7 Hz, 1H), 8.27 (dd, J = 8.7, 2.7 Hz,
1H), 8.57 (s, 1H), 12.26 (s, 1H). Anal. Calcd for C18H16F3NO5: C,
56.40; H, 4.21; N, 3.65. Found: C, 56.49; H, 4.17; N, 3.65.
5.1.1.70. (2E)-3-[2-[(3-Chloropyridin-2-yl)oxy]-4-(2-methoxy-
ethoxy)phenyl]acrylic acid (37c).
Compound 37c (colorless
crystals) was prepared from 12c in 97% yield following a similar
procedure to provide 7a. Mp 150.5–150.9 °C (EtOH/hexane). 1H
NMR (DMSO-d6): d 3.28 (s, 3H), 3.61–3.66 (m, 2H), 4.09–4.16 (m,
2H), 6.41 (d, J = 16.2 Hz, 1H), 6.80 (d, J = 2.4 Hz, 1H), 6.92 (dd,
J = 8.9, 2.4 Hz, 1H), 7.20 (dd, J = 7.8, 4.8 Hz, 1H), 7.48 (d,
J = 16.2 Hz, 1H), 7.83 (d, J = 8.9 Hz, 1H), 8.06 (dd, J = 4.8, 1.6 Hz,
1H), 8.10 (dd, J = 7.8, 1.6 Hz, 1H), 12.29 (s, 1H). Anal. Calcd for
C17H16ClNO5: C, 58.38; H, 4.61; N, 4.00. Found: C, 58.32; H, 4.46;
N, 3.91.
5.1.1.71.
(2E)-3-[2-[(3,5-Dichloropyridin-2-yl)oxy]-4-(2-
Compound 37d
methoxyethoxy)phenyl]acrylic acid (37d).
5.1.1.75. (2E)-3-[2-[(3-Chloropyridin-2-yl)oxy]-4-(2-methoxy-
(colorless crystals) was prepared from 12d in 92% yield following
a similar procedure to provide 7a. Mp 182.3–184.0 °C (THF/hex-
ane). 1H NMR (DMSO-d6): d 3.28 (s, 3H), 3.61–3.65 (m, 2H), 4.10–
4.14 (m, 2H), 6.42 (d, J = 16.2 Hz, 1H), 6.85 (d, J = 2.4 Hz, 1H),
6.92 (dd, J = 8.7, 2.4 Hz, 1H), 7.47 (d, J = 16.2 Hz, 1H), 7.83 (d,
J = 8.7 Hz, 1H), 8.16 (d, J = 2.1 Hz, 1H), 8.41 (d, J = 2.1 Hz, 1H),
12.31 (s, 1H). Anal. Calcd for C17H15Cl2NO5: C, 53.14; H, 3.94; N,
3.65. Found: C, 53.24; H, 3.96; N, 3.48.
ethoxy)phenyl]-N-(pentylsulfonyl)acryl-amide (13c).
To a
stirred mixture of 37c (427 mg, 1.22 mmol), pentane-1-sulfon-
amide (193 mg, 1.28 mmol), MNBA15 (506 mg, 1.47 mmol) and
DMAP (151 mg, 1.24 mmol) in acetonitrile (10 mL) was added
TEA (385 mg, 3.80 mmol) at room temperature, and the mixture
was stirred at room temperature for 96 h. The reaction mixture
was concentrated, sat. NH4Cl was added to the residue, and the
mixture was extracted with EtOAc. The organic layer was washed
with brine, dried over MgSO4, and concentrated under reduced
pressure. The obtained residue was subjected to silica gel chroma-
tography (hexane-EtOAc, 1:1) to give a white solid, which was
recrystallized from EtOAc/hexane to give 13c (523 mg, 88%) as col-
orless crystals. Mp 134.7–136.6 °C. 1H NMR (CDCl3): d 0.89 (t,
J = 7.0 Hz, 3H), 1.26–1.45 (m, 4H), 1.76–1.88 (m, 2H), 3.42 (s, 3H),
3.42–3.50 (m, 2H), 3.71–3.76 (m, 2H), 4.09–4.14 (m, 2H), 6.40 (d,
J = 15.9 Hz, 1H), 6.66 (d, J = 2.5 Hz, 1H), 6.84 (dd, J = 8.7, 2.5 Hz,
1H), 7.03 (dd, J = 7.6, 4.9 Hz, 1H), 7.55 (d, J = 8.7 Hz, 1H), 7.75–
7.88 (m, 3H), 8.03 (dd, J = 4.9, 1.5 Hz, 1H). Anal. Calcd for
5.1.1.72. (2E)-3-[2-({5-[(tert-Butoxycarbonyl)amino]-3-methyl-
pyridin-2-yl}oxy)-4-(2-methoxyethoxy)phenyl]acrylic acid
(37e).
Compound 37e (colorless crystals) was prepared from
12g in 99% yield following a similar procedure to provide 7a. Mp
159.0–160.0 °C (EtOH/hexane). 1H NMR (DMSO-d6): d 1.46 (s,
9H), 2.29 (s, 3H), 3.27 (s, 3H), 3.59–3.64 (m, 2H), 4.05–4.11 (m,
2H), 6.39 (d, J = 16.1 Hz, 1H), 6.51 (d, J = 2.4 Hz, 1H), 6.82 (dd,
J = 8.7, 2.4 Hz, 1H), 7.59 (d, J = 16.1 Hz, 1H), 7.78 (d, J = 8.7 Hz,
1H), 7.87 (s, 1H), 7.95 (d, J = 2.4 Hz, 1H), 9.43 (s, 1H), 12.21 (s,
1H). Anal. Calcd for C23H28N2O7: C, 62.15; H, 6.35; N, 6.30. Found:
C, 61.97; H, 6.26; N, 6.19.
C22H27ClN2O6S: C, 54.71; H, 5.63; N, 5.80. Found: C, 54.72; H,
5.63; N, 5.81.

K. Rikimaru et al. / Bioorg. Med. Chem. 20 (2012) 3332–3358
3351
5.1.1.76. (2E)-3-[2-[(3,5-Dichloropyridin-2-yl)oxy]-4-(2-
methoxyethoxy)phenyl]-N-(pentylsulfonyl)acrylamide
ganic layer was washed with sat. NaHCO3 and brine, dried over
MgSO4, filtered and evaporated under reduced pressure. The resid-
ual oil was purified by basic silica gel chromatography (hexane-
EtOAc, 85:15 to 65:35) to give 14 (10.1 g, quant.) as a white solid.
The solid was recrystallized from EtOAc/hexane to give white
feathered crystals. Mp 85.0–85.5 °C. 1H NMR (CDCl3): d 1.88 (t,
J = 6.2 Hz, 1H), 3.44 (s, 3H), 3.69–3.83 (m, 2H), 4.02–4.17 (m, 2H),
4.54 (d, J = 6.2 Hz, 2H), 6.71 (d, J = 2.6 Hz, 1H), 6.89 (dd, J = 8.5,
2.6 Hz, 1H), 7.43 (d, J = 8.5 Hz, 1H), 8.00 (d, J = 1.9 Hz, 1H), 8.25
(dd, J = 2.1, 0.9 Hz, 1H). Anal. Calcd for C16H15NO4ClF3: C, 50.87;
H, 4.00; N, 3.71. Found: C, 50.82; H, 3.95; N, 3.52.
(13d).
Compound 13d (colorless crystals) was prepared from
37d and pentane-1-sulfonamide in 43% yield following a similar
procedure to provide 8f. Mp 119.0–120.3 °C (EtOAc/hexane). 1H
NMR (CDCl3): d 0.89 (t, J = 7.2 Hz, 3H), 1.25–1.45 (m, 4H), 1.78–
1.88 (m, 2H), 3.43 (s, 3H), 3.44–3.50 (m, 2H), 3.73–3.77 (m, 2H),
4.10–4.15 (m, 2H), 6.37 (d, J = 15.6 Hz, 1H), 6.65 (d, J = 2.4 Hz,
1H), 6.86 (dd, J = 8.7, 2.4 Hz, 1H), 7.57 (d, J = 8.7 Hz, 1H), 7.65 (s,
1H), 7.79–7.84 (m, 2H), 7.96 (d, J = 2.4 Hz, 1H). Anal. Calcd for
C22H26Cl2N2O6S: C, 51.07; H, 5.06; N, 5.41. Found: C, 51.02; H,
5.01; N, 5.29.
5.1.1.81. 2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}-4-
5.1.1.77. tert-Butyl [6-(5-(2-methoxyethoxy)-2-{(2E)-3-oxo-3-
(2-methoxyethoxy)benzyl acetate (38).
To a solution of 14
[(pentylsulfonyl)amino]prop-1-en-1-yl}phenoxy)-5-methyl-
(11.5 g, 30.4 mmol) in pyridine (25 mL) was added Ac2O (25 mL),
and the mixture was stirred at room temperature for 1 h. The reac-
tion was quenched with sat. NaHCO3, and the mixture was ex-
tracted with EtOAc. The organic layer was washed with 1 M HCl,
sat. NaHCO3, and brine, dried over MgSO4, filtrated and concen-
trated under reduced pressure. The obtained residue was subjected
to silica gel column chromatography (hexane-EtOAc, 100:0 to 3:2)
give 14 (8.80 g, 76%) as a white solid. Recrystallization from EtOAc/
hexane gave white crystals. Mp 52.5–53.0 °C. 1H NMR (CDCl3): d
1.90 (s, 3H), 3.44 (s, 3H), 3.65–3.78 (m, 2H), 4.05–4.17 (m, 2H),
5.00 (s, 2H), 6.75 (d, J = 2.4 Hz, 1H), 6.88 (dd, J = 8.5, 2.4 Hz, 1H),
7.40 (d, J = 8.7 Hz, 1H), 7.99 (d, J = 1.9 Hz, 1H), 8.26 (dd, J = 2.2,
1.0 Hz, 1H). Anal. Calcd for C18H17ClF3NO5: C, 51.50; H, 4.08; N,
3.34. Found: C, 51.33; H, 3.92; N, 3.33.
pyridin-3-yl]carbamate (13e).
Compound 13e (colorless
crystals) was prepared from 37e and pentane-1-sulfonamide in
86% yield following a similar procedure to provide 13c. Mp
149.5–150.2 °C (EtOAc/hexane). 1H NMR (CDCl3):
d 0.88 (t,
J = 7.0 Hz, 3H), 1.28–1.47 (m, 4H), 1.53 (s, 9H), 1.75–1.86 (m, 2H),
2.24 (s, 3H), 3.36–3.45 (m, 5H), 3.67–3.72 (m, 2H), 4.03–4.08 (m,
2H), 6.39 (s, 1H), 6.42 (d, J = 15.9 Hz, 1H), 6.49–6.51 (m, 1H), 6.72
(dd, J = 8.7, 2.5 Hz, 1H), 7.46 (d, J = 8.7 Hz, 1H), 7.82–7.88 (m, 3H),
8.71 (br s, 1H). Anal. Calcd for C28H39N3O8S: C, 58.21; H, 6.80; N,
7.27. Found: C, 58.30; H, 7.03; N, 6.87.
5.1.1.78. (2E)-3-[2-[(5-Amino-3-methylpyridin-2-yl)oxy]-4-(2-
methoxyethoxy)phenyl]-N-(pentylsulfonyl)acrylamide
dihy-
drochloride (13f). To a solution of 13e (327 mg, 0.566 mmol)
in MeOH (3 mL) was added 10% HCl in MeOH solution (3 mL), and
the mixture was stirred at room temperature for 14 h and further
at 45 °C for 3 h. The reaction mixture was concentrated under re-
duced pressure, and the obtained crude crystals were recrystallized
from MeOH/IPE to give 13f (207 mg, 66%) as colorless crystals. Mp
206.0–207.2 °C. 1H NMR (DMSO-d6): d 0.80–0.85 (m, 3H), 1.14–
1.29 (m, 4H), 1.30–1.49 (m, 2H), 2.39 (s, 3H), 3.09–3.27 (m, 4H),
3.30 (s, 3H), 3.65–3.67 (m, 2H), 4.13–4.16 (m, 2H), 6.21–6.24 (m,
1H), 6.96 (dd, J = 8.7, 2.4 Hz, 1H), 7.05 (d, J = 2.4 Hz, 1H), 7.39 (d,
J = 8.7 Hz, 1H), 7.66–7.67 (m, 2H), 11.93 (s, 1H). Anal. Calcd for
5.1.1.82. Methyl 3-[2-{[3-chloro-5-(trifluoromethyl)pyridin-2-
yl]oxy}-4-(2-methoxyethoxy)phenyl]-2,2-dimethylpropanoate
(15).
To a solution of 38 (1.80 g, 4.29 mmol) in toluene
(20 mL) were added 1-methoxy-2-methyl-1-(trimethylsiloxy)pro-
pene (3.50 mL, 17.2 mmol) and MgClO4 (1.44 g, 6.45 mmol), and
the mixture was stirred at 50 °C for 3 h. Water was added to the
reaction mixture, and the mixture was diluted with EtOAc. The or-
ganic layer was washed with brine, dried over MgSO4, filtrated and
concentrated under reduced pressure. The obtained residue was
subjected to silica gel column chromatography (hexane-EtOAc,
100:0 to 7:3) to give 15 (1.78 g, 90%) as a colorless oil. 1H NMR
(CDCl3): d 1.17 (s, 6H), 2.73 (s, 2H), 3.43 (s, 3H), 3.66 (s, 3H), 3.73
(dd, J = 5.5, 4.0 Hz, 2H), 4.08 (dd, J = 5.5, 4.0 Hz, 2H), 6.66 (d,
J = 2.4 Hz, 1H), 6.80 (dd, J = 8.6, 2.5 Hz, 1H), 7.15–7.24 (m, 1H),
7.98 (d, J = 2.1 Hz, 1H), 8.25 (dd, J = 2.3, 0.9 Hz, 1H).
C23H33Cl2N3O6S: C, 50.18; H, 6.04; N, 7.63. Found: C, 50.07; H,
5.98; N, 7.60.
5.1.1.79. (2E)-3-[2-{[5-(Acetylamino)-3-methylpyridin-2-
yl]oxy}-4-(2-methoxyethoxy)phenyl]-N-(pentylsulfonyl)acryl-
amide (13g).
To a solution of 13f (321 mg, 0.606 mmol) in
pyridine (5 mL) were added Ac2O (445 mg, 4.36 mmol) and DMAP
(145 mg, 1.19 mmol), and the mixture was stirred at room temper-
ature for 7 h. The reaction mixture was concentrated, sat. NH4Cl
was added to the residue, and the mixture was extracted with
EtOAc. The organic layer was washed with brine, dried over MgSO4,
and concentrated. The obtained residue was subjected to silica gel
column chromatography (EtOAc). The crude crystals were recrys-
tallized from EtOAc/hexane to give 13g (150 mg, 49%) as colorless
crystals. Mp 187.9–188.2 °C. 1H NMR (CDCl3): d 0.87 (t, J = 7.1 Hz,
3H), 1.22–1.40 (m, 4H), 1.70–1.84 (m, 2H), 2.05–2.18 (m, 6H),
3.30–3.44 (m, 5H), 3.66–3.75 (m, 2H), 4.04–4.09 (m, 2H), 6.23–
6.70 (m, 3H), 7.42 (d, J = 8.7 Hz, 1H), 7.70–8.10 (m, 3H), 9.61 (br
s, 1H). Anal. Calcd for C25H33N3O7S: C, 57.79; H, 6.40; N, 8.09.
Found: C, 57.66; H, 6.43; N, 8.11.
5.1.1.83. 3-[2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}-
4-(2-methoxyethoxy)phenyl]-2,2-dimethylpropanoic
acid
(39). To a solution of 15 (1.75 g, 3.79 mmol) in THF (4 mL)
was added conc. H2SO4-AcOH-H2O (1:6:6, 8 mL), and the mixture
was stirred at 80 °C for 24 h. After being allowed to cool to room
temperature, the mixture was extracted with EtOAc. The organic
layer was washed with water and brine, dried over MgSO4, filtrated
and concentrated under reduced pressure. The obtained residue
was subjected to silica gel column chromatography (hexane-
EtOAc, 9:1 to 1:1) to give 39 (1.36 g, 80%) as a colorless oil. 1H
NMR (CDCl3): d 1.20 (s, 6H), 2.77 (s, 2H), 3.43 (s, 3H), 3.73 (dd,
J = 5.0, 3.9 Hz, 2H), 4.04–4.12 (m, 2H), 6.67 (d, J = 1.9 Hz, 1H),
6.81 (dd, J = 8.6, 1.6 Hz, 1H), 7.21 (d, J = 8.5 Hz, 1H), 7.98 (s, 1H),
8.25 (d, J = 0.9 Hz, 1H).
5.1.1.80. [2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}-4-
5.1.1.84. Sodium {3-[2-{[3-chloro-5-(trifluoromethyl)pyridin-2-
yl]oxy}-4-(2-methoxyethoxy)phenyl]-2,2-dimethylpropanoyl}
(2-methoxyethoxy)phenyl]methanol (14).
To a stirred solu-
tion of 11b (9.86 g, 26.2 mmol) in THF (40 mL) and MeOH (30 mL)
was added NaBH4 (2.60 g, 169 mmol) at 0 °C and the mixture was
stirred the same temperature for 10 min. The reaction was
quenched with 1 M HCl at 0 °C and diluted with EtOAc and the or-
(pentylsulfonyl)azanide (16).
3-[2-{[3-Chloro-5-(trifluoro-
methyl)pyridin-2-yl]oxy}-4-(2-methoxyethoxy)phenyl]-2,2-dimet
hyl-N-(pentylsulfonyl)propanamide (a colorless oil) was prepared
from 39 and pentane-1-sulfonamide in 96% yield following a

3352
K. Rikimaru et al. / Bioorg. Med. Chem. 20 (2012) 3332–3358
similar procedure to provide 7a. 1H NMR (CDCl3): d 0.82–0.95 (m,
3H), 1.25 (s, 6H), 1.28–1.48 (m, 4H), 1.75 (tt, J = 7.6, 7.6 Hz, 2H),
2.76 (s, 2H), 3.34–3.42 (m, 2H), 3.43 (s, 3H), 3.73 (dd, J = 5.4,
3.9 Hz, 2H), 4.09 (dd, J = 5.5, 4.0 Hz, 2H), 6.68 (d, J = 2.4 Hz, 1H),
6.82 (dd, J = 8.7, 2.6 Hz, 1H), 7.20 (d, J = 8.7 Hz, 1H), 7.82 (br s,
1H), 8.01 (d, J = 2.3 Hz, 1H), 8.28 (dd, J = 2.1, 0.9 Hz, 1H).
To a solution of 3-[2-{[3-chloro-5-(trifluoromethyl)pyridin-2-
yl]oxy}-4-(2-methoxyethoxy)phenyl]-2,2-dimethyl-N-(pentylsulfo
nyl)propanamide (1.23 g, 2.12 mmmol) in MeOH (2 mL) was added
1 M NaOH (2.12 mL, 2.12 mmol) at room temperature for 2 h, and
the reaction mixture was concentrated under reduced pressure.
The obtained residue was washed with cold MeOH to give 16
(982 mg, 77%) as white crystals. Mp 190.5–191.0 °C. 1H NMR
(DMSO-d6): d 0.76–0.86 (m, 3H), 0.90 (s, 6H), 1.07–1.32 (m, 4H),
1.37–1.61 (m, 2H), 2.55 (s, 2H), 2.78–2.95 (m, 2H), 3.29 (s, 3H),
3.55–3.68 (m, 2H), 3.94–4.11 (m, 2H), 6.66–6.78 (m, 2H), 7.27–
7.36 (m, 1H), 8.49 (dd, J = 2.3, 0.9 Hz, 1H), 8.53 (d, J = 1.9 Hz, 1H).
Anal. Calcd for C25H31ClF3N2NaO6S: C, 49.79; H, 5.18; N, 4.65.
Found: C, 49.74; H, 5.12; N, 4.55.
5.1.1.88. 2-(Benzyloxy)-4-(2-methoxyethoxy)benzaldehyde
(19b). Compound 19b (white crystals) was prepared from 9
and benzyl bromide in 79% yield following a similar procedure to
provide 7c. Mp 67.5–68.0 °C. 1H NMR (CDCl3): d 3.45 (s, 3H),
3.67–3.88 (m, 2H), 4.08–4.20 (m, 2H), 5.15 (s, 2H), 6.50–6.69 (m,
2H), 7.31–7.52 (m, 5H), 7.83 (d, J = 9.2 Hz, 1H), 10.38 (s, 1H). Anal.
Calcd for C17H18O4: C, 71.31; H, 6.34. Found: C, 71.15; H, 6.26.
5.1.1.89.
(19c).
2-Benzyloxy-4-methoxymethoxybenzaldehyde
Compound 19c (a colorless oil) was prepared from 4b
and benzyl bromide in 72% yield following a similar procedure to
provide 7c. 1H NMR (CDCl3): d 3.47 (s, 3H), 5.16 (s, 2H), 5.20 (s,
2H), 6.58–6.76 (m, 2H), 7.30–7.48 (m, 5H), 7.82 (d, J = 9.1 Hz,
1H), 10.40 (s, 1H).
5.1.1.90. Ethyl(2E)-3-(2-benzyloxy-4-isopropoxyphenyl)acrylate
(20a).
Compound 20a (a colorless oil) was prepared from 19a
in 97% yield following the procedure to provide 6a. 1H NMR
(CDCl3): d 1.31 (t, J = 7.1 Hz, 3H), 1.31 (d, J = 6.0 Hz, 6H), 4.23 (q,
J = 7.2 Hz, 2H), 4.44–4.63 (m, 1H), 5.13 (s, 2H), 6.42 (d,
J = 16.2 Hz, 1H), 6.46–6.52 (m, 2H), 7.29–7.50 (m, 6H), 7.99 (d,
J = 16.2 Hz, 1H).
5.1.1.85. 2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}-
4-(2-methoxyethoxy)benzyl (pentylsulfonyl)carbamate
(17).
To a stirred solution of 14 (473 mg, 1.25 mmol) in DMF
5.1.1.91. Ethyl
nyl)acrylate (20c).
(2E)-3-(2-benzyloxy-4-methoxymethoxyphe-
Compound 20c (a yellow oil) was pre-
(5 mL) was added CDI (295 mg, 1.82 mmol) and the mixture was
stirred at room temperature for 1 h and at 40 °C for 30 min, then
pentane-1-sulfonamide (289 mg, 1.91 mmol) and DBU (0.30 mL,
2.09 mmol) were successively added to the mixture, which was
stirred at the same temperature overnight. DMAP (215 mg,
1.76 mmol) was added to the mixture, and after 1 h, the reaction
was quenched with 1 M HCl and extracted with EtOAc. The com-
bined organic layer was washed with 1 M HCl, sat. NaHCO3 and
brine, dried over MgSO4, filtered and evaporated under reduced
pressure. The residual oil was purified by silica gel chromatogra-
phy twice (hexane-EtOAc, 9:1 to 65:35, then hexane-EtOAc, 7:1
to 4:1) to give a white solid, which was recrystallized from
EtOAc/hexane to give 17 (373 mg, 54%) as white crystals. Mp
130–132 °C. 1H NMR (CDCl3): d 0.83–0.94 (m, 3H), 1.19–1.49 (m,
4H), 1.70–1.88 (m, 2H), 3.27–3.41 (m, 2H), 3.44 (s, 3H), 3.69–
3.78 (m, 2H), 4.04–4.14 (m, 2H), 5.13 (s, 2H), 6.75 (d, J = 2.4 Hz,
1H), 6.88 (dd, J = 8.6, 2.5 Hz, 1H), 6.94 (s, 1H), 7.42 (d, J = 8.5 Hz,
1H), 8.01 (d, J = 1.9 Hz, 1H), 8.26 (dd, J = 2.2, 1.0 Hz, 1H). Anal. Calcd
for C22H26ClF3N2O7S: C, 47.61; H, 4.72; N, 5.05. Found: C, 47.56; H,
4.77; N, 4.90.
pared from 19c in 96% yield following a similar procedure to
provide 6a. 1H NMR (CDCl3): d 1.32 (t, J = 7.2 Hz, 3H), 3.46 (s,
3H), 4.23 (q, J = 7.2 Hz, 2H), 5.14 (s, 2H), 5.16 (s, 2H), 6.44 (d,
J = 16.2 Hz, 1H), 6.65–6.69 (m, 2H), 7.28–7.49 (m, 6H), 8.00 (d,
J = 16.2 Hz, 1H).
5.1.1.92. Ethyl (2E)-3-(2-benzyloxy-4-hydroxyphenyl)acrylate
(20d).
Compound 20d (colorless prisms) was prepared from
20c in 78% yield following a similar procedure to provide 33b.
Mp 131–133 °C (EtOAc/hexane). 1H NMR (CDCl3): d 1.32 (t,
J = 7.2 Hz, 3H), 4.23 (q, J = 7.2 Hz, 2H), 5.12 (s, 2H), 5.25 (s, 1H),
6.36–6.53 (m, 3H), 7.29–7.51 (m, 6H), 8.00 (d, J = 16.2 Hz, 1H). Anal.
Calcd For C18H18O4: C, 72.47; H, 6.08. Found: C, 72.24; H, 5.94.
5.1.1.93. Ethyl (2E)-3-{2-(benzyloxy)-4-[2-(2-oxopyrrolidin-1-
yl)ethoxy]phenyl}acrylate (20e).
To a stirred solution of
20d (2.01 g, 6.74 mmol) in THF (100 mL) was added 1-(2-hydroxy-
ethyl)-2-pyrrolidone (0.80 mL, 7.12 mmol), followed by triphenyl-
phosphine (2.65 g, 10.1 mmol) and DEAD (2.2 M in toluene,
5.50 mL, 12.1 mmol) at 0 °C and the mixture was allowed to warm
to room temperature. After being stirred for 3 h, the mixture was
concentrated in vacuo, and the residual oil was purified by silica
gel chromatography (hexane-EtOAc, 3:1 to EtOAc to EtOAc-MeOH,
9:1) to give 20e (4.01 g, quant.) as a white solid. Recrystallization
from EtOAc/hexane gave white crystals. Mp 94–97 °C. 1H NMR
(CDCl3): d 1.32 (t, J = 7.2 Hz, 3H), 1.84–2.12 (m, 2H), 2.39 (t,
J = 8.1 Hz, 2H), 3.47–3.57 (m, 2H), 3.66 (t, J = 5.2 Hz, 2H), 4.10 (t,
J = 5.2 Hz, 2H), 4.23 (q, J = 7.2 Hz, 2H), 5.14 (s, 2H), 6.43 (d,
J = 16.2 Hz, 1H), 6.47–6.52 (m, 2H), 7.29–7.54 (m, 6H), 7.99 (d,
J = 16.2 Hz, 1H). Anal. Calcd for C24H27NO5: C, 70.40; H, 6.65; N,
3.42. Found: C, 70.22; H, 6.61; N, 3.28.
5.1.1.86. 2-Hydroxy-4-isopropoxybenzaldehyde (18a).
A
mixture of 3 (100 g, 0.724 mol) and DIPEA (127 mL, 0.730 mol) in
THF (350 mL) was added 2-iodomethame (72.9 mL, 0.730 mol)
with stirring at room temperature, then stirred for 3 h. To this mix-
ture was added 2-iodomethane (20 mL, 0.20 mol), and the mixture
waas stirred under reflux for 12 h. The mixture was diluted with
water, extracted with EtOAc. The organic layer was washed with
brine, dried over MgSO4, filtered, then concentrated in vacuo. The
residue was purified by silica gel chromatography (hexane-EtOAc,
20:1 to 10:1) to give 18a (30.9 g, 24%) as a pale yellow oil. 1H NMR
(CDCl3): d 1.37 (d, J = 6.0 Hz, 6H), 4.48–4.72 (m, 1H), 6.40 (d,
J = 2.5 Hz, 1H), 6.49 (dd, J = 8.8, 2.2 Hz, 1H), 7.41 (d, J = 8.5 Hz,
1H), 9.69 (s, 1H), 11.47 (s, 1H).
5.1.1.94. Ethyl 3-(2-hydroxy-4-isopropoxyphenyl)propanoate
(21a).
A stirred solution of 20a (172 g, 0.505 mol) in THF
(250 mL) and EtOH (250 mL) was hydrogenated under atmospheric
pressure with 10% Pd/C (wet, 30.0 g, 14.1 mmol) at room tempera-
ture for 40 h. The catalyst was removed by filtration and the filtrate
was concentrated in vacuo. The residual oil was passed through sil-
ica gel to give 20a (112 g, 88%) as a pale-yellow oil. 1H NMR
(CDCl3): d 1.24 (t, J = 7.2 Hz, 3H), 1.31 (d, J = 6.0 Hz, 6H), 2.59–
5.1.1.87. 2-Benzyloxy-4-isopropoxybenzaldehyde (19a).
Com-
pound 19a (a pale-yellow oil) was prepared from 18a and benzyl bro-
mide in 91% yield following a similar procedure to provide 7c. 1H
NMR (CDCl3): d 1.35 (d, J = 6.2 Hz, 6H), 4.49–4.71 (m, 1H), 5.15 (s,
2H), 6.49 (d, J = 2.1 Hz, 1H), 6.54 (dd, J = 8.7, 1.9 Hz, 1H), 7.31–7.50
(m, 5H), 7.82 (d, J = 8.7 Hz, 1H), 10.37 (d, J = 0.8 Hz, 1H).

K. Rikimaru et al. / Bioorg. Med. Chem. 20 (2012) 3332–3358
3353
2.72 (m, 2H), 2.75–2.88 (m, 2H), 4.15 (q, J = 7.2 Hz, 2H), 4.37–4.57
(m, 1H), 6.38–6.45 (m, 1H), 6.44–6.48 (m, 1H), 6.94 (d, J = 8.3 Hz,
1H), 7.42 (s, 1H).
for C18H17NO4ClF3: C, 53.54; H, 4.24; N, 3.47. Found: C, 53.61; H,
4.16; N, 3.43.
5.1.1.100. 3-[2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}-
4-(2-methoxyethoxy)phenyl]-2-methoxypropanoic acid
5.1.1.95. Methyl 3-[2-hydroxy-4-(2-methoxyethoxy)phenyl]-2-
methoxypropanoate (21b).
To a solution of 19b (11.9 g,
(40b).
Compound 40b (white crystals) was prepared from
41.6 mmol) in THF (80 mL) were added methyl methoxyacetate
(6.16 g, 59.2 mmol) and KOt-Bu (6.81 g, 60.7 mmol), and the
mixture was stirred at room temperature for 5 h. The reaction
was quenched with 1 M HCl, and the mixture was diluted with
EtOAc. The organic layer was washed with sat. NaHCO3 and
brine, dried over MgSO4, filtrated and concentrated under re-
duced pressure. The obtained residue was subjected to silica
gel column chromatography (hexane-EtOAc, 100:1 to 2:3) to give
a yellow oil (20b).
25b in 54% yield following a similar procedure to provide 34a.
Mp 93–96 °C (EtOAc/hexane). 1H NMR (CDCl3): d 2.81–2.92 (m,
1H), 3.00–3.10 (m, 1H), 3.28 (s, 3H), 3.42–3.45 (m, 3H), 3.70–3.76
(m, 2H), 4.00 (dd, J = 7.8, 4.6 Hz, 1H), 4.07–4.12 (m, 2H), 6.69 (d,
J = 2.6 Hz, 1H), 6.83 (dd, J = 8.6, 2.5 Hz, 1H), 7.27 (d, J = 8.5 Hz,
1H), 8.00 (d, J = 1.9 Hz, 1H), 8.26 (dd, J = 2.1, 0.9 Hz, 1H). Anal. Calcd
for C19H19NO6ClF3: C, 50.73; H, 4.26; N, 3.11. Found: C, 50.90; H,
4.37; N, 3.19.
To a solution of 20b in MeOH (100 mL) was added 10% Pd/C
(wet, 5.01 g, 2.35 mmol), and the mixture was stirred under hydro-
gen atmosphere at room temperature for 5 h. The reaction mixture
was filtrated, and the filtrate was concentrated under reduced
pressure. The obtained residue was subjected to silica gel column
chromatography (hexane-EtOAc, 19:1 to 55:45) to give 21b
(3.45 g, 29%) as a yellow oil. 1H NMR (CDCl3): d 2.91–3.11 (m,
2H), 3.44 (s, 3H), 3.49 (s, 3H), 3.70–3.77 (m, 5H), 4.01–4.12 (m,
3H), 6.43 (dd, J = 8.3, 2.6 Hz, 1H), 6.51 (d, J = 2.6 Hz, 1H), 6.91 (d,
J = 8.3 Hz, 1H), 7.69 (s, 1H).
5.1.1.101. 3-{2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}-
4-[2-(2-oxopyrrolidin-1-yl)ethoxy]phenyl}propanoic acid
(40c).
added NaH (60% dispersion in oil, 464 mg, 11.6 mmol) at 0 °C
and after 30 min, 2,3-dichloro-5-(trifluoromethyl)pyridine
To a stirred solution of 21c (2.90 g, 6.74 mmol) was
(1.50 mL, 10.8 mmol) was added to the mixture, which was al-
lowed to warm to room temperature. After being stirred for 1 h,
the reaction was quenched with sat. NH4Cl and extracted with
EtOAc and the combined organic layer was washed with brine,
dried over MgSO4, filtered and evaporated under reduced pressure.
The residual oil was purified by silica gel chromatography (hexane-
EtOAc, 1:1 to EtOAc) to give crude ethyl 3-{2-{[3-chloro-5-(trifluo-
romethyl)pyridin-2-yl]oxy}-4-[2-(2-oxopyrrolidin-1-yl)-ethoxy]-
phenyl}propanoate (22c) (3.17 g) as an orange oil.
To a stirred solution of 22c (3.17 g) in THF (15 mL) and EtOH
(15 mL) was added 1 M NaOH (16.0 mL, 16.0 mmol) and the mix-
ture was stirred at room temperature for 12 h, and additional
1 M NaOH (15.0 mL, 15.0 mmol) was added and after 1 h, 1 M
NaOH (10.0 mL, 10.0 mmol) was added and the mixture was stir-
red for 1 h. The reaction was acidified with 1 M HCl (41.0 mL,
41.0 mmol), and concentrated in vacuo, and the residue was dis-
solved into EtOAc, and the organic layer was washed with brine,
dried over MgSO4, filtered and concentrated under reduced pres-
sure. The residual solid was purified by silica gel chromatography
(hexane-EtOAc, 3:1 to EtOAc to EtOAc-MeOH, 9:1) to give 40c
(0.85 g, 27%) as a white solid. Recrystallization from EtOAc/hexane
gave a white powder. Mp 145.0–145.5 °C. 1H NMR (CDCl3): d 1.90–
2.11 (m, 2H), 2.38 (t, J = 8.1 Hz, 2H), 2.63 (t, J = 7.4 Hz, 2H), 2.78 (t,
J = 7.3 Hz, 2H), 3.48–3.62 (m, 2H), 3.66 (t, J = 5.1 Hz, 2H), 4.07 (t,
J = 5.1 Hz, 2H), 6.64 (d, J = 2.4 Hz, 1H), 6.77 (dd, J = 8.5, 2.6 Hz,
1H), 7.12–7.27 (m, 1H), 7.99 (d, J = 1.9 Hz, 1H), 8.26 (dd, J = 2.2,
1.0 Hz, 1H). Anal. Calcd for C21H20ClF3N2O5: C, 53.34; H, 4.26; N,
5.92. Found: C, 53.45; H, 4.32; N, 5.80.
5.1.1.96. Ethyl 3-{2-hydroxy-4-[2-(2-oxopyrrolidin-1-yl)eth-
oxy]phenyl}propanoate (21c).
Compound 21c (a white pow-
der) was prepared from 20e in quantitative yield following a
similar procedure to provide 21a. Mp 112–115 °C (EtOAc/IPE). 1H
NMR (CDCl3): d 1.24 (t, J = 7.2 Hz, 3H), 1.94–2.08 (m, 2H), 2.38 (t,
J = 8.1 Hz, 2H), 2.61–2.74 (m, 2H), 2.78–2.93 (m, 2H), 3.57 (t,
J = 7.1 Hz, 2H), 3.65 (t, J = 5.1 Hz, 2H), 4.06 (t, J = 5.1 Hz, 2H), 4.14
(q, J = 7.2 Hz, 2H), 6.40 (dd, J = 8.3, 2.6 Hz, 1H), 6.46 (d, J = 2.4 Hz,
1H), 6.96 (d, J = 8.3 Hz, 1H), 7.74 (s, 1H). Anal. Calcd for
C23H28ClF3N2O6S 0.25H2O: C, 62.66; H, 7.27; N, 4.30. Found: C,
62.45; H, 7.12; N, 4.25.
5.1.1.97. Ethyl 3-(2-{[3-chloro-5-(trifluoromethyl)pyridin-2-
yl]oxy}-4-isopropoxyphenyl)propanoate (22a).
Compound
22a (a pale-yellow oil) was prepared from 21a and 2,3-dichloro-
5-(trifluoromethyl)pyridine in 88% yield following a similar proce-
dure to provide 5a. 1H NMR (CDCl3): d 1.21 (t, J = 7.2 Hz, 3H), 1.32
(d, J = 6.0 Hz, 6H), 2.50–2.62 (m, 2H), 2.68–2.84 (m, 2H), 4.09 (q,
J = 7.1 Hz, 2H), 4.38–4.58 (m, 1H), 6.63 (d, J = 2.6 Hz, 1H), 6.76
(dd, J = 8.5, 2.6 Hz, 1H), 7.21 (d, J = 8.5 Hz, 1H), 7.98 (d, J = 1.7 Hz,
1H), 8.27 (dd, J = 2.3, 0.9 Hz, 1H).
5.1.1.98. Methyl 3-[2-{[3-chloro-5-(trifluoromethyl)pyridin-2-
yl]oxy}-4-(2-methoxyethoxy)phenyl]-2-methoxypropanoate
5.1.1.102. 3-(2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}-
4-isopropoxyphenyl)-5-(pentylsulfonyl)propanamide (23a). Com-
pound 23a (white crystals) was prepared from 40a and
pentane-1-sulfonamide in 50% yield following a similar procedure
to provide 8a. Mp 94–95 °C (EtOAc/hexane). 1H NMR (CDCl3): d
0.85–0.94 (m, 3H), 1.24–1.41 (m, 10H), 1.60–1.73 (m, 2H), 2.55 (t,
J = 7.2 Hz, 2H), 2.96 (t, J = 7.1 Hz, 2H), 3.12–3.20 (m, 2H), 4.36–
4.55 (m, 1H), 6.45 (d, J = 2.4 Hz, 1H), 6.74 (dd, J = 8.4, 2.5 Hz, 1H),
7.17 (d, J = 8.5 Hz, 1H), 8.08 (d, J = 2.1 Hz, 1H), 8.33–8.43 (m, 1H).
Anal. Calcd for C23H28N2O5SClF3: C, 51.44; H, 5.26; N, 5.22. Found:
C, 51.36; H, 5.21; N, 5.21.
(22b).
Compound 22b (a yellow oil) was prepared from 21b
and 2,3-dichloro-5-(trifluoromethyl)pyridine in 75% yield follow-
ing a similar procedure to provide 5a. 1H NMR (CDCl3): d 1.21 (t,
J = 7.2 Hz, 3H), 1.32 (d, J = 6.0 Hz, 6H), 2.50–2.62 (m, 2H), 2.68–
2.84 (m, 2H), 4.09 (q, J = 7.1 Hz, 2H), 4.38–4.58 (m, 1H), 6.63 (d,
J = 2.6 Hz, 1H), 6.76 (dd, J = 8.5, 2.6 Hz, 1H), 7.21 (d, J = 8.5 Hz,
1H), 7.98 (d, J = 1.7 Hz, 1H), 8.27 (dd, J = 2.3, 0.9 Hz, 1H).
5.1.1.99. 3-(2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}-
4-isopropoxyphenyl)propanoic acid (40a).
Compound 40a
(a white powder) was prepared from 21a in quantitative yield fol-
lowing a similar procedure to provide 34a. Mp 107.0–107.5 °C
(EtOAc/hexane). 1H NMR (CDCl3): d 1.32 (d, J = 6.2 Hz, 6H), 2.55–
2.70 (m, 2H), 2.70–2.85 (m, 2H), 4.36–4.61 (m, 1H), 6.62 (d,
J = 2.4 Hz, 1H), 6.77 (dd, J = 8.5, 2.4 Hz, 1H), 7.21 (d, J = 8.5 Hz,
1H), 7.98 (d, J = 2.1 Hz, 1H), 8.26 (dd, J = 2.1, 0.9 Hz, 1H). Anal. Calcd
5.1.1.103. 3-(2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}-
4-isopropoxyphenyl)-N-pentylpropanamide (23b).
stirred solution of 40a (315 mg, 0.776 mmol) in THF (10 mL) was
added SOCl2 (0.1 mL, 1.39 mmol), followed by DMF (10 L,
0.130 mmol) at 0 °C. After being stirred for 2 h at the same
To
a
l

3354
K. Rikimaru et al. / Bioorg. Med. Chem. 20 (2012) 3332–3358
temperature, the mixture was concentrated in vacuo and the resi-
due was dissolved into THF (2 mL). To the solution was added pen-
tylamine (0.20 mL, 1.72 mmol), followed by pyridine (0.50 mL,
6.19 mmol) and DMAP (12.1 mg, 0.124 mmol) at room tempera-
ture, and the mixture was stirred for 2 h. The reaction was quenched
with 1 M HCl and diluted with EtOAc and the organic layer was
washed sat. NaHCO3 and brine, dried over MgSO4, filtered and con-
centrated under reduced pressure. The residual solid was recrystal-
lized from EtOAc/hexane to give 23b (166 mg, 45%) as white
crystals. Mp 106–107.5 °C. 1H NMR (CDCl3): d 0.86 (t, J = 7.1 Hz,
3H), 1.11–1.48 (m, 12H), 2.39 (t, J = 7.5 Hz, 2H), 2.80 (t, J = 7.4 Hz,
2H), 3.02–3.18 (m, 2H), 4.38–4.63 (m, 1H), 5.42 (s, 1H), 6.59 (d,
J = 2.6 Hz, 1H), 6.75 (dd, J = 8.5, 2.6 Hz, 1H), 7.20 (d, J = 8.5 Hz, 1H),
8.00 (d, J = 1.7 Hz, 1H), 8.26 (dd, J = 2.2, 1.0 Hz, 1H). Anal. Calcd for
20 min, which was stirred at room temperature for 2 days. The
reaction was quenched with sat. NH4Cl on ice-bath and ex-
tracted with EtOAc/hexane (1:1) and the combined organic layer
was washed with water and brine, dried over MgSO4, filtered
and concentrated under reduced pressure. The residual oil was
purified by silica gel chromatography (hexane-EtOAc, 100:0 to
3:2) to give 25 (0.85 g, 9%) as a colorless oil. 1H NMR (CDCl3):
d 1.22–1.29 (m, 1H), 1.28 (t, J = 7.2 Hz, 3H), 1.51 (ddd, J = 9.3,
5.0, 4.3 Hz, 1H), 1.76 (ddd, J = 8.2, 5.1, 4.4 Hz, 1H), 2.63 (ddd,
J = 9.2, 6.8, 4.3 Hz, 1H), 3.44 (s, 3H), 3.47 (s, 3H), 3.66–3.76 (m,
2H), 4.04–4.10 (m, 2H), 4.13–4.21 (m, 2H), 5.14–5.21 (m, 2H),
6.48 (dd, J = 8.5, 2.4 Hz, 1H), 6.71 (d, J = 2.4 Hz, 1H), 6.82 (d,
J = 8.5 Hz, 1H).
C
23H28ClF3N2O3: C, 58.41; H, 5.97; N, 5.92. Found: C, 58.25; H,
5.1.1.108. Ethyl 2-[2-{[3-chloro-5-(trifluoromethyl)pyridin-2-
yl]oxy}-4-(2-methoxyethoxy)phenyl]cyclopropanecarboxylate
5.99; N, 5.94.
(26).
To a stirred solution of 25 (0.85 g, 2.62 mmol) in acetone
5.1.1.104. 3-[2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}-
4-(2-methoxyethoxy)phenyl]-2-methoxy-N-(pentylsulfo-
(10 mL) was added 1 M HCl (5 mL) and the mixture was stirred at
50 °C for 6 h. After being cooled to room temperature, 1 M NaOH
(5 mL) was added to the mixture and extracted with EtOAc. The or-
ganic layer was washed with water and brine, dried over MgSO4,
filtered and concentrated under reduced pressure to give ethyl 2-
[2-hydroxy-4-(2-methoxyethoxy)phenyl]cyclopropanecarboxylate
(0.80 g) as a brown oil.
To a stirred solution of the obtained ethyl 2-[2-hydroxy-4-(2-
methoxyethoxy)phenyl]cyclopropanecarboxylate (0.80 g) and
K2CO3 (724 mg, 5.23 mmol) in DMF was added 2,3-dichloro-5-(tri-
nyl)propanamide (23c).
prepared from 40b and pentane-1-sulfonamide in 23% yield fol-
lowing
Compound 23c (white crystals) was
a
similar procedure to provide 8f. Mp 76.0–78.0 °C
(EtOAc/hexane). 1H NMR (CDCl3): d 0.86–0.95 (m, 3H), 1.23–1.49
(m, 4H), 1.64–1.85 (m, 2H), 2.87 (dd, J = 14.4, 7.1 Hz, 1H), 3.08–
3.37 (m, 6H), 3.43 (s, 3H), 3.66–3.76 (m, 2H), 3.95 (dd, J = 7.1,
4.1 Hz, 1H), 4.03–4.15 (m, 2H), 6.65 (d, J = 2.4 Hz, 1H), 6.81 (dd,
J = 8.5, 2.6 Hz, 1H), 7.21 (d, J = 8.7 Hz, 1H), 8.02 (d, J = 1.9 Hz, 1H),
8.29 (dd, J = 2.2, 1.0 Hz, 1H), 8.86 (s, 1H). Anal. Calcd for
fluoromethyl)pyridine (726 lL, 5.21 mmol) and the mixture was
C
24H30ClF3N2O7S: C, 49.44; H, 5.19; N, 4.80. Found: C, 49.51; H,
stirred at room temperature overnight. The reaction was quenched
with 1 M HCl and extracted with EtOAc. The organic layer was
washed with water and brine, dried over MgSO4, filtered and con-
centrated under reduced pressure. The residual oil was purified by
silica gel chromatography (hexane-EtOAc, 65:35) to give 26
(488 mg, 41%) as a colorless oil. 1H NMR (CDCl3): d 1.17 (t,
J = 7.2 Hz, 3H), 1.20–1.32 (m, 1H), 1.38 (ddd, J = 9.2, 4.8, 4.7 Hz,
1H), 1.62 (ddd, J = 8.1, 5.1, 4.8 Hz, 1H), 2.33 (ddd, J = 9.1, 6.7,
4.3 Hz, 1H), 3.44 (s, 3H), 3.70–3.76 (m, 2H), 3.87–4.00 (m, 2H),
4.07–4.13 (m, 2H), 6.72 (d, J = 2.4 Hz, 1H), 6.82 (dd, J = 8.6, 2.5 Hz,
1H), 7.04 (d, J = 8.5 Hz, 1H), 7.96 (d, J = 1.7 Hz, 1H), 8.25 (dd,
J = 2.2, 1.0 Hz, 1H).
5.08; N, 4.86.
5.1.1.105.
3-{2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-
yl]oxy}-4-[2-(2-oxopyrrolidin-1-yl)ethoxy]phenyl}-N-(pentylsul
fonyl)propanamide (23d). Compound 23d (a white powder)
was prepared from 40c and pentane-1-sulfonamide in 74% yield
following a similar procedure to provide 8a. Mp 123–126 °C
(EtOAc/IPE). 1H NMR (CDCl3): d 0.86–0.93 (m, 3H), 1.20–1.47 (m,
4H), 1.59–1.78 (m, 2H), 1.93–2.18 (m, 2H), 2.38 (t, J = 8.1 Hz, 2H),
2.56 (t, J = 7.2 Hz, 2H), 2.94 (t, J = 7.2 Hz, 2H), 3.14–3.27 (m, 2H),
3.54 (t, J = 7.1 Hz, 2H), 3.64 (t, J = 5.1 Hz, 2H), 4.04 (t, J = 5.2 Hz,
2H), 6.49 (d, J = 2.6 Hz, 1H), 6.75 (dd, J = 8.5, 2.6 Hz, 1H), 7.20 (d,
J = 8.5 Hz, 1H), 8.08 (d, J = 1.7 Hz, 1H), 8.35 (dd, J = 2.3, 0.9 Hz,
1H), 9.02 (s, 1H). Anal. Calcd for C26H31ClF3N3O6S: C, 51.53; H,
5.16; N, 6.93. Found: C, 51.27; H, 5.06; N, 6.89.
5.1.1.109. 2-[2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}-
4-(2-methoxyethoxy)phenyl]cyclopropanecarboxylic
acid
(41). Compound 41 (white crystals) was prepared from 26
in 99% yield following a similar procedure to provide 34a. Mp
121.0–121.5 °C (EtOAc/hexane). 1H NMR (CDCl3): d 1.36 (ddd,
J = 8.3, 6.9, 4.7 Hz, 1H), 1.44 (ddd, J = 9.3, 4.8 Hz, 1H), 1.62 (ddd,
J = 8.1, 5.1, 4.7 Hz, 1H), 2.39 (ddd, J = 9.1, 6.9, 4.5 Hz, 1H), 3.44 (s,
3H), 3.65–3.79 (m, 2H), 3.96–4.14 (m, 2H), 6.74 (d, J = 2.4 Hz,
1H), 6.82 (dd, J = 8.6, 2.5 Hz, 1H), 7.04 (d, J = 8.7 Hz, 1H), 7.94 (d,
J = 1.9 Hz, 1H), 8.25 (dd, J = 2.2, 1.0 Hz, 1H). Anal. Calcd for
5.1.1.106. Ethyl (2E)-3-[4-(2-methoxyethoxy)-2-(methoxyme-
thoxy)phenyl]acrylate (24).
To a stirred solution of 10
(7.40 g, 27.8 mmol) and K2CO3 (7.40 g, 53.5 mmol) in MeCN
(150 mL) was added MOMCl (2.40 mL, 31.6 mmol) at room tem-
perature, and the mixture was stirred for 2 h. Water was added
to the mixture and extracted with EtOAc. The organic layer was
washed with water and brine, dried over MgSO4, filtered and con-
centrated under reduced pressure to give 24 (9.01 g, quant.) as a
colorless oil. 1H NMR (CDCl3): d 1.33 (t, J = 7.2 Hz, 3H), 3.45 (s,
3H), 3.49 (s, 3H), 3.72–3.78 (m, 2H), 4.10–4.17 (m, 2H), 4.25 (q,
J = 7.2 Hz, 2H), 5.23 (s, 2H), 6.40 (d, J = 16.2 Hz, 1H), 6.58 (dd,
J = 8.6, 2.4 Hz, 1H), 6.77 (d, J = 2.4 Hz, 1H), 7.46 (d, J = 8.7 Hz, 1H),
7.95 (d, J = 16.2 Hz, 1H).
C19H17ClF3NO5: C, 52.85; H, 3.97; N, 3.24. Found: C, 52.87; H,
4.02; N, 3.17.
5.1.1.110. 2-[2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}-
4-(2-methoxyethoxy)phenyl]-N-(pentylsulfonyl)cyclopropane-
carboxamide (27).
Compound 27 (white crystals) was pre-
pared from 41 and pentane-1-sulfonamide in 67% yield following
a similar procedure to provide 8f. Mp 184.0–184.5 °C (EtOAc/hex-
ane). 1H NMR (CDCl3): d 0.83–0.94 (m, 3H), 1.22–1.48 (m, 6H),
1.57–1.63 (m, 1H), 1.78 (tt, J = 7.6, 7.6 Hz, 2H), 2.25–2.58 (m, 1H),
3.21–3.39 (m, 2H), 3.43 (s, 3H), 3.62–3.80 (m, 2H), 3.96–4.19 (m,
2H), 6.69 (d, J = 2.4 Hz, 1H), 6.82 (dd, J = 8.6, 2.5 Hz, 1H), 7.05 (d,
J = 8.7 Hz, 1H), 8.01 (d, J = 2.1 Hz, 1H), 8.26 (dd, J = 2.1, 0.9 Hz,
1H). Anal. Calcd for C24H28ClF3N2O6S: C, 51.02; H, 5.00; N, 4.96.
Found: C, 51.02; H, 5.04; N, 4.94.
5.1.1.107. Ethyl 2-[4-(2-methoxyethoxy)-2-(methoxyme-
thoxy)phenyl]cyclopropanecarboxylate (25).
To a stirred
suspension of trimethylsulfoxonium iodide (9.17 g, 41.7 mmol)
in DMSO (50 mL) was added NaH (60% dispersion in oil,
1.67 g, 41.8 mmol) at 0 °C and the mixture was stirred at room
temperature for 1 h. Then a solution of 24 (9.01 g, 29.0 mmol)
in DMSO (75 mL) was added to the mixture dropwise over

K. Rikimaru et al. / Bioorg. Med. Chem. 20 (2012) 3332–3358
3355
5.1.1.111. 3-[2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}-
4-(2-methoxyethoxy)phenyl]propan-1-ol (28). To a stirred
5.1.1.114.
yl]oxy}-4-(2-methoxyethoxy)phenyl]propyl}-1H-isoindole-
1,3(2H)-dione (30). To stirred solution of 28 (4.94 g,
2-{3-[2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-
solution of 7b (12.1 g, 26.9 mmol) in THF (60 mL) was added DI-
BAL-H (1.5 M in toluene, 65.0 mL, 97.5 mmol) dropwise at 0 °C
and the mixture was stirred at the same temperature for 10 min.
The reaction was quenched with sat. NH4Cl (5.40 mL) dropwise
on ice-bath and the mixture was allowed to warm to at room tem-
perature with stirring. After being stirred for 1 h, the precipitates
were filtered off and the filtrate was concentrated under reduced
pressure to give 28 (7.69 g, 70%) as a white powder. Recrystalliza-
tion from EtOAc/hexane gave white crystals. Mp 74.5–75.5 °C
(EtOAc/hexane). 1H NMR (CDCl3): d 1.37 (s, 1H), 1.77–1.89 (m,
2H), 2.54 (t, J = 7.5 Hz, 2H), 3.44 (s, 3H), 3.60 (q, J = 6.1 Hz, 2H),
3.68–3.78 (m, 2H), 4.05–4.12 (m, 2H), 6.67 (d, J = 2.6 Hz, 1H),
6.84 (dd, J = 8.5, 2.4 Hz, 1H), 7.22 (d, J = 8.7 Hz, 1H), 7.98 (d,
J = 2.3 Hz, 1H), 8.26 (d, J = 1.1 Hz, 1H). Anal. Calcd for
a
12.2 mmol) in EtOAc (100 mL) was added TEA (3.50 mL,
25.1 mmol), followed by MsCl (1.40 mL, 18.1 mmol) at room tem-
perature and the mixture was stirred at the same temperature for
1 h. The reaction was quenched with 1 M HCl and diluted with
EtOAc and the separated organic layer was washed with sat. NaH-
CO3, and brine, dried over MgSO4, filtered and concentrated under
reduced pressure to give crude 3-[2-{[3-chloro-5-(trifluoro-
methyl)pyridin-2-yl]oxy}-4-(2-methoxyethoxy)phenyl]propyl
methanesulfonate (6.15 g) as a pale-yellow oil.
To a stirred solution of crude intermediate (6.15 g) in DMF
(50 mL) was added potassium phthalimide (2.46 g, 13.3 mmol)
and the mixture was stirred at 80 °C for 3 h. After being cooled
to room temperature, the reaction was quenched with water and
extracted with EtOAc and the organic layer was washed with water
and brine, dried over MgSO4, filtered and concentrated under re-
duced pressure. The residual solid was washed with IPE to give
30 (6.39 g, 98%) as a white solid. Recrystallization from EtOAc/hex-
ane gave white crystals. Mp 101–103 °C. 1H NMR (CDCl3): d 1.82–
1.99 (m, 2H), 2.39–2.53 (m, 2H), 3.43 (s, 3H), 3.63–3.77 (m, 4H),
4.02–4.11 (m, 2H), 6.67 (d, J = 2.6 Hz, 1H), 6.82 (dd, J = 8.4, 2.5 Hz,
1H), 7.23 (d, J = 8.7 Hz, 1H), 7.67–7.73 (m, 2H), 7.76–7.83 (m,
2H), 7.86 (d, J = 2.1 Hz, 1H), 8.22 (d, J = 1.1 Hz, 1H). Anal. Calcd for
C18H19ClF3NO4: C, 53.28; H, 4.72; N, 3.45. Found: C, 53.21; H,
4.74; N, 3.25.
5.1.1.112. 3-[2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}-
4-(2-methoxyethoxy)phenyl]propyl butylcarbamate (29a).
To a
stirred solution of 28 (0.30 g, 0.740 mmol) in DMF (7 mL) was
added CDI (0.18 g, 1.11 mmol) and the mixture was stirred at
60 °C. After being stirred for 1 h, butylamine (0.22 mL, 2.23 mmol)
was added to the mixture, and after 6 h, the reaction was quenched
with water and extracted with EtOAc and the combined organic
layer was washed with brine, dried over Na2SO4, filtered and evap-
orated under reduced pressure. The residual oil was purified by sil-
ica gel chromatography (hexane-EtOAc, 9:1 to 7:3) to give a crude
solid, which was recrystallized from IPE/hexane to give 29a
(297 mg, 80%) as a white powder. Mp 91.7–91.8 °C. 1H NMR
(CDCl3): d 0.92 (t, J = 7.4 Hz, 3H), 1.31–1.46 (m, 4H), 1.80–1.95
(m, 2H), 2.50 (t, J = 7.1 Hz, 2H), 3.09–3.20 (m, 2H), 3.44 (s, 3H),
3.72–3.75 (m, 2H), 4.00 (t, J = 6.5 Hz, 2H), 4.07–4.10 (m, 2H), 4.54
(s, 1H), 6.68 (d, J = 3.6 Hz, 1H), 6.82 (dd, J = 8.4, 2.4 Hz, 1H), 7.20
(d, J = 8.4 Hz, 1H), 7.97 (d, J = 2.4 Hz, 1H), 8.25 (dd, J = 2.0, 1.1 Hz,
1H). Anal. Calcd for C23H28ClF3N2O5: C, 54.71; H, 5.59; N, 5.55.
Found: C, 54.74; H, 5.44; N, 5.54.
C26H22ClF3N2O5: C, 58.38; H, 4.15; N, 5.24. Found: C, 58.38; H,
4.22; N, 5.13.
5.1.1.115. 3-[2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}-
4-(2-methoxyethoxy)phenyl]propan-1-amine (31).
To
a
stirred solution of 30 (6.12 g, 11.4 mmol) in MeOH (100 mL) was
added hydrazine hydrate (4.02 g, 80.3 mmol) and the mixture
was stirred at 50 °C for 2 h. The mixture was concentrated in vacuo,
and the residue was washed with Et2O and the filtrates were evap-
orated. The residue was washed with Et2O and the filtrates were
concentrated in vacuo. The oil was dissolved into EtOAc and the or-
ganic layer was washed sat. NaHCO3-brine (1:1) and brine, dried
over MgSO4, filtered and concentrated under reduced pressure to
give 31 (2.51 g, 54%) as a dark-brown oil. 1H NMR (CDCl3): d
1.51–1.95 (m, 4H), 2.40–2.55 (m, 2H), 2.68 (t, J = 7.0 Hz, 2H), 3.44
(s, 3H), 3.65–3.80 (m, 2H), 4.09 (d, 2H), 6.67 (d, J = 2.4 Hz, 1H),
6.83 (dd, J = 8.4, 2.5 Hz, 1H), 7.21 (d, J = 8.7 Hz, 1H), 7.98 (d,
J = 2.1 Hz, 1H), 8.26 (d, J = 0.9 Hz, 1H).
5.1.1.113. 3-[2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}-
4-(2-methoxyethoxy)phenyl]propyl (pentylsulfonyl)carbamate
(29b).
To
a
stirred solution of triphosgene (67.9 mg,
0.229 mmol) in DCM (5 mL) was added 28 (205 mg, 0.504 mmol),
followed by pyridine (0.10 mL, 1.24 mmol) at 0 °C. After comple-
tion of the addition, the mixture was concentrated in vacuo, and
the residue was dissolved into THF (10 mL). To the THF solution
were added successively pentane-1-sulfonamide (125 mg,
0.827 mmol), DIPEA (0.40 mL, 2.34 mmol) and DMAP (61.5 mg,
0.503 mmol), and the mixture was stirred at room temperature
for 10 min. The reaction was quenched with 1 M HCl and diluted
with EtOAc and the saparated organic layer was washed with sat.
NaHCO3 and brine, dried over MgSO4, filtered and evaporated un-
der reduced pressure. The residual oil was purified by silica gel
chromatography twice (hexane-EtOAc, 19:1 to 1:1, then hex-
ane-EtOAc, 9:1 to 1:1) to give a white solid, which was recrystal-
lized from EtOAc/hexane to give 29b (34.9 mg, 12%) as white
crystals. Mp 97.5–99.0 °C. 1H NMR (CDCl3): d 0.91 (t, J = 7.1 Hz,
3H), 1.24–1.47 (m, 4H), 1.72–2.07 (m, 4H), 2.57 (t, J = 7.3 Hz,
2H), 3.27–3.39 (m, 2H), 3.43 (s, 3H), 3.70–3.75 (m, 2H), 4.05–
4.12 (m, 2H), 4.16 (t, J = 6.3 Hz, 2H), 6.68 (d, J = 2.4 Hz, 1H),
6.82 (dd, J = 8.5, 2.6 Hz, 1H), 7.18 (d, J = 8.5 Hz, 1H), 8.01 (d,
J = 2.1 Hz, 1H), 8.28 (d, J = 0.9 Hz, 1H). Anal. Calcd for
5.1.1.116. N-{3-[2-{[3-Chloro-5-(trifluoromethyl)pyridin-2-
yl]oxy}-4-(2-methoxyethoxy)phenyl]propyl}-pentane-1-sulfon-
amide (32a).
To a stirred solution of 31 (1.01 g, 2.49 mmol)
in pyridine (2.5 mL) and EtOAc (10 mL) was added pentane-1-sul-
fonyl chloride (0.50 g, 2.93 mmol) at room temperature, and the
mixture was stirred at the same temperature for 1.5 h. The reac-
tion was quenched with sat. NH4Cl and diluted with EtOAc and
the organic layer was washed with 1 M HCl, sat. NaHCO3, water
and brine, dried over MgSO4, filtered and evaporated under re-
duced pressure. The residual oil was purified by silica gel chroma-
tography (hexane-EtOAc, 19:1 to 3:2) to give a white solid, which
was recrystallized from EtOAc/hexane to give 32a (198 mg, 15%)
as white crystals. Mp 87–90 °C. 1H NMR (CDCl3): d 0.90 (t,
J = 6.9 Hz, 3H), 1.21–1.41 (m, 4H), 1.64–1.93 (m, 4H), 2.53 (t,
J = 7.4 Hz, 2H), 2.85–2.99 (m, 2H), 3.06 (t, J = 6.6 Hz, 2H), 3.43 (s,
3H), 3.65–3.81 (m, 2H), 4.03–4.11 (m, 2H), 4.13–4.25 (m, 1H),
6.66 (d, J = 2.5 Hz, 1H), 6.84 (dd, J = 8.5, 2.7 Hz, 1H), 7.19 (d,
J = 8.5 Hz, 1H), 8.00 (d, J = 1.9 Hz, 1H), 8.18–8.28 (m, 1H). Anal.
Calcd for C23H30ClF3N2O5S: C, 51.25; H, 5.61; N, 5.20. Found: C,
51.37; H, 5.82; N, 5.02.
C24H30ClF3N2O7S: C, 49.44; H, 5.19; N, 4.80. Found: C, 49.55; H,
5.21; N, 4.60.

3356
K. Rikimaru et al. / Bioorg. Med. Chem. 20 (2012) 3332–3358
5.1.1.117. Butyl {3-[2-{[3-chloro-5-(trifluoromethyl)pyridin-2-
yl]oxy}-4-(2-methoxyethoxy)phenyl]-propyl}carbamate
(32b). Compound 32b (white crystals) was prepared from 31
and butyl chloroformate in 3% yield following a similar procedure
to provide 32a. Mp 91.5–92.0 °C (EtOAc/hexane). 1H NMR (CDCl3):
d 0.92 (t, J = 7.3 Hz, 3H), 1.27–1.44 (m, 2H), 1.50–1.62 (m, 2H),
1.70–1.83 (m, 2H), 2.48 (t, J = 7.5 Hz, 2H), 3.09–3.18 (m, 2H), 3.43
(s, 3H), 3.62–3.76 (m, 2H), 4.01 (t, J = 6.5 Hz, 2H), 4.04–4.20 (m,
2H), 4.69 (s, 1H), 6.67 (d, J = 2.4 Hz, 1H), 6.83 (dd, J = 8.5, 2.6 Hz,
1H), 7.20 (d, J = 8.5 Hz, 1H), 7.99 (d, J = 1.9 Hz, 1H), 8.26 (d,
J = 1.1 Hz, 1H). Anal. Calcd for C23H28ClF3N2O5: C, 54.71; H, 5.59;
N, 5.55. Found: C, 54.62; H, 5.44; N, 5.35.
After washing the OPAQUE PLATE with PBS, 45
medium containing 0.1% fatty acid free-BSA and 5
pounds were added to the plate, which was then cultured in 5%
CO2 at 37 °C for 1 day. After removing the medium, 20 L of PICA-
GENE-LT7.5 (Wako Pure Chemical Ind., Ltd., Japan), which was di-
luted to half with HANK’S BALANCED SALT SOLUTION, was added
to each well. After stirring, luciferase activities were determined
in microplate-based luminescence reader (Perkinnelmer, U.S.A.).
l
l
L of HAM F12
L of test com-
l
5.2.5. Transient co-transfection assay of hPPARa and hPPARd
COS-1 cells were seeded at 5ꢂ106 cells in 150 cm2 tissue culture
flask, and cultured in 5% CO2 at 37 °C overnight. Transfections were
performed with LipofectAMINE (Life Technologies, Inc., U.S.A.)
according to the instructions of manufacturer. Briefly, the transfec-
5.2. Biology
tion mixture contained 125
agent, 2.5 g of each expression plasmid pMCMVneo-hPPAR
(pMCMVneo-hPPARd) and pMCMVneo-hRXR , 5 g of reporter
plasmid pGL3-PPREꢂ4-tk-luc-neo, and 5 g of pRL-tk (Promega,
lL of LipofectAMINE, 100 lL of plus re-
5.2.1. Metabolic stability assay
l
a
Human or rat hepatic microsomes were purchased from Xeno-
tech, LLC (Lenexa, KS). An incubation mixture with a final volume
of 0.1 mL consisted of microsomal protein in 50 mmol/L phosphate
a
l
l
U.S.A.). Cells were incubated in 25 mL of transfection mixture for
3 h in 5% CO2 at 37 °C. After adding 25 mL of DMEM medium (Life
Technologies, Inc., U.S.A.) containing 0.1% fatty acid free-BSA, the
cells were then incubated for 1 day in 5% CO2 at 37 °C. After trans-
fection, cells were detached by treating with trypsin-EDTA (Life
Technologies INC., U.S.A.) centrifuged and then suspended in
DMEM medium containing 0.1% fatty acid free-BSA. The suspended
cells were added into an OPAQUE PLATE (white 96 well half area
buffer (pH 7.4) and 1 lmol/L test compound. The concentration of
hepatic microsomal protein was 0.2 mg/mL. An NADPH-generating
system containing 50 mmol/L MgCl2, 50 mmol/L glucose-6-phos-
phate, 5 mmol/L beta-NADP+ and 15 unit/mL glucose-6-phosphate
dehydrogenase was prepared and added to the incubation mixture
with a 10% volume of the reaction mixture. After the addition of
the NADPH-generating system, the mixture was incubated at
37 °C for 0 and 20 min. The reaction was terminated by the addi-
tion of equivalent volume of MeCN to that of the reaction mixture.
All incubations were made in duplicate. The amounts of test com-
pound in the reaction mixtures were measured by HPLC analysis
which was performed by Nemoto Science Co., Ltd (Tokyo, Japan).
Metabolic stability was assessed as disappearance rate of the par-
ent compound. Disappearance rate is represented as a percentage
of the amount of the parent compound in the reaction mixture
for 20 min relative to that in the reaction mixture for 0 min taken
as 100%.
plate, COSTAR, U.S.A.) at the density of 5ꢂ103 cells/well in 45
lL
of DMEM medium containing 0.1% fatty acid free-BSA and 5 lL of
test compounds and then cultured in 5% CO2 at 37 °C for 2 days.
After removing the medium, 20 L of PICAGENE-LT7.5 (Wako Pure
l
Chemical Ind., Ltd., Japan), which was diluted to half with HANK’S
BALANCED SALT SOLUTION, was added to each well. After stirring,
luciferase activities were determined in microplate-based lumines-
cence reader (Perkinnelmer, U.S.A.).
5.2.6. Evaluation of plasma glucose- and triglyceride-lowering
activities in Wistar fatty rats
5.2.2. Pharmacokinetic analyses in Wistar fatty rats
Male Wistar fatty rats were obtained from Takeda Rabics (Ja-
pan) and were used in these experiments. Throughout the study,
they were housed in metal cages and fed a commercial diet CE-2
(Clea, Japan) and water ad libitum. At the beginning of experiment,
blood samples were withdrawn from tail vein with heparin as anti-
coagulant, and initial body weight was measured. Plasma samples
were obtained from blood samples by centrifugation. Plasma levels
of glucose and triglyceride were measured enzymatically using
Autoanalyzer 7080 (Hitachi, Japan). Rats were divided based on
body weight, plasma glucose and triglyceride (n = 5/group). Wistar
fatty rats were orally administered test compounds suspended in
0.5% methylcellurose solution once daily for 7 days. The next day
of final administration, blood samples were withdrawn from tail
vein, and body weight was measured. After obtaining of plasma
samples by centrifugation of blood samples, we measured plasma
glucose and triglyceride. The change (%) from the initial levels of
plasma glucose and triglyceride after 7-day treatment was calcu-
lated in each group. The degree of the lowering effect in each group
was estimated from the relative ratio of the change (%) in each
group to the change in the control group. Then, the ED25 for the
glucose- and triglyceride-lowering effects of test compounds were
calculated from the dose-response curves of the relative ratios gen-
erated by logistic regression using the PCP systems.
The test compound was administered to nonfasted rats. After
oral and intravenous administration, blood samples were collected.
The blood samples were centrifuged to obtain the plasma fraction.
The plasma samples were deproteinized with MeCN containing an
internal standard. After centrifugation, the supernatant was di-
luted and centrifuged again. The compound concentrations in the
supernatant were measured by LC/MS/MS.
5.2.3. Establishment of a stable transformed cell expressing hu
man PPAR
poter gene
The full length human PPAR
c1, human RXRa, and PPAR responsive luciferase re
c1, full length human RXRa, and
PPAR responsive luciferase reporter gene were stably expressed
in CHO-K1 cells. Transfection of mammalian expression plasmid,
pVGRXR2-hPPARc-zeo, and reporter plasmid, pGL3-(PPREx4)-Tk-
neo, into the cells was performed by electroporation using a Gene
Pulser (Bio-Rad, Japan). G418 (Life Technologies Inc., U.S.A.) and
Zeocin (Invitrogen, U.S.A.) resistant clones were selected and
examined for their ability to introduce liciferase expression in
the presence of pioglitazone. Finally, we selected the clone,
PPARc:RXRa:4ERPP/CHO-K1 No.10, which expressed high levels
of luciferase activity by pioglitazone.
5.2.4. Transactivation assay of hPPAR
c
1
5.3. Docking study
PPAR
c
:RXR
a
:PPREꢂ4/CHO-K1 cells were used for transactiva-
tion assays of hPPAR
c
1. These cells were seeded into an OPAQUE
The atomic coordinates of the crystal structures (1FM6 and
1PRG) were obtained from the web site of RCSB protein data bank
(http://www.rcsb.org/pdb/home/home.do). Both protein structures
PLATE (white 96 well half area plate, COSTAR, U.S.A.) at the density
of 1 ꢂ 104 cells/well, and cultured in 5% CO2 at 37 °C overnight.

K. Rikimaru et al. / Bioorg. Med. Chem. 20 (2012) 3332–3358
3357
The initial solutions were refined with REFMAC,30 and the models
were visually inspected and manually built and rebuilt using the
XtalView/Xfit program suite.31 The crystallographic refinement
statistics are presented in Table 8.
Table 8
X-ray data collection and refinement statistics
8f
Crystal
Space group
Unit cell dimensions
P212121
a = 58.8 Å
b = 62.3 Å
c = 157.6 Å
2
Acknowledgment
Molecules/asymmetric unit
Data collection
Resolution [Å] (outer shell)
Observations (unique)
Redundancy
Completeness overall (outer shell)
I/d (I) overall (outer shell)
Rsymm overall (outer shell)
Refinement
We would like to thank Robert Wynands for his help in prepar-
ing the manuscript and the staff of the Advanced Light Source,
which is supported by the Director, Office of Science, Office of Basic
Energy Science of the U.S. Department of Energy under Contract
No. DE-AC02–05CH11231. We would also like to thank Shinkichi
Suzuki for supporting the optimization study by conducting
high-throughput organic synthesis.
50–2.43 (2.52–2.43)
125131 (22489)
5.6
99.7 (99.4)%
20.4 (3.3)
0.082 (0.524)
Resolution [Å]
Reflections used
R-factor
Rfree
20–2.5
19584
0.196
0.269
0.009
1.11
References and notes
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RMS bonds [Å]
RMS angles [o]
Average B-value [Å2]
37.0
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were added hydrogens and then only hydrogens were energetically
optimized in MOE (ver. 2000.02, Chemical Computing Group Inc,
Canada.). Each compound was docked into the PPARc-LBD using
the GOLD program (ver. 2.0, the Cambridge crystallographic data
centre, UK) with the default parameter set. After some manual
adjustment to remove large steric hindrances, docking poses show-
ing high score (Gold score) were subjected to energy minimization
using MMFF94s force field in MOE. During the energy minimization
procedure firstly whole protein structure was fixed and secondly
that within 3.5 Å from the each ligand was relaxed.
8. Recent Review on PPARc agonists Cho, N.; Momose, Y. Curr. Top. Med. Chem.
2008, 8, 1483.
9. Berger, J. P.; Akiyama, T. E.; Meinke, P. T. PPARs: therapeutic targets for
metabolic disease Trends in Pharmacol. Sci. 2005, 26, 244.
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5.4. X-ray co-crystallography study
5.4.1. Protein expression and purification
The ligand binding domain (LBD) of human PPAR
c
(NM_005037; aa 202–475) was cloned into pET28a vector (Nova-
gen) and expressed as an N-terminal 6xHis fusion protein in
E. coli. Fusion protein was purified by Ni affinity chromatography
(Probond, Invitrogen) at pH 7.9, followed by anion exchange (Q Se-
pharose FF, GE Healthcare) and size exclusion chromatography
(Superdex S200, GE Healthcare). Before crystallization, the
protein solution was concentrated to 16 mg/ml by centrifugal
ultrafiltration.
5.4.2. Crystallization and data collection
Crystals of the PPARc-LBD 8f complex were obtained by pre-
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incubating a 15 mg/ml protein preparation with 2.0 mM 8f, and
were grown at 20 °C by sitting-drop vapor diffusion using Nanovo-
lume Crystallization techniques with 50 nL of protein solution and
50 nL of reservoir containing 20% polyethylene glycol 3000, 0.1 M
TRIS, pH 7.0 and 0.2 M calcium acetate.
Single crystals were harvested in reservoir solutions supple-
mented with 25% ethylene glycol as cryoprotectant and flash-fro-
zen by direct immersion in liquid nitrogen. X-ray diffraction data
were collected at the Advanced Light Source in Berkeley, California
at Beam Line 5.0.3 equipped with an ADSC Quantum 4r CCD detec-
tor. The diffraction intensities were integrated and scaled using the
HKL2000 program suite.27 Data collection statistics are presented
in Table 8.
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analogue was obtained in higher yield (63%) under the same reaction
conditions when compared to the ethyl ester 25 (9%) due to steric hinderance.
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The 8f complex structure was determined by molecular
replacement using MolRep28 and 2PRG29 as the search model.

3358
K. Rikimaru et al. / Bioorg. Med. Chem. 20 (2012) 3332–3358
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