3-(2-Aminocarbonylphenyl)propanoic acid analogs as potent and selective EP3 receptor antagonists. Part 2: Optimization of the side chains to improve in vitro and in vivo potencies

Article abstract of DOI:10.1016/j.bmc.2009.12.068

A series of 3-[2-{[(3-methyl-1-phenylbutyl)amino]carbonyl}-4-(phenoxymethyl)phenyl]propanoic acid analogs were synthesized and evaluated for their in vitro potency. In most cases, introduction of one or two substituents into the two phenyl moieties resulted in the tendency of an increase or retention of in vitro activities. Several compounds, which showed excellent subtype selectivity, were evaluated for their inhibitory effect against PGE₂-induced uterine contraction in pregnant rats, which is thought to be mediated by the EP3 receptor subtype. The structure-activity relationships (SARs) are also discussed.

Full text of DOI:10.1016/j.bmc.2009.12.068

Bioorganic & Medicinal Chemistry 18 (2010) 1641–1658
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry
journal homepage: www.elsevier.com/locate/bmc
3-(2-Aminocarbonylphenyl)propanoic acid analogs as potent and selective
EP3 receptor antagonists. Part 2: Optimization of the side chains to
improve in vitro and in vivo potencies
a
a
a
a
b
Masaki Asada a, , Maki Iwahashi , Tetsuo Obitsu , Atsushi Kinoshita , Yoshihiko Nakai , Takahiro Onoda ,
Toshihiko Nagase a, Motoyuki Tanaka a, Yoshiyuki Yamaura a, Hiroya Takizawa a, Ken Yoshikawa a,
Kazutoyo Sato a, Masami Narita a, Shuichi Ohuchida a, Hisao Nakai a, Masaaki Toda a
*
a Minase Research Institute, Ono Pharmaceutical Co., Ltd, Shimamoto, Mishima, Osaka 618-8585, Japan
b Fukui Research Institute, Ono Pharmaceutical Co., Ltd, Technoport, Yamagishi, Mikuni, Sakai, Fukui 913-8538, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
A series of 3-[2-{[(3-methyl-1-phenylbutyl)amino]carbonyl}-4-(phenoxymethyl)phenyl]propanoic acid
analogs were synthesized and evaluated for their in vitro potency. In most cases, introduction of one
or two substituents into the two phenyl moieties resulted in the tendency of an increase or retention
of in vitro activities. Several compounds, which showed excellent subtype selectivity, were evaluated
for their inhibitory effect against PGE2-induced uterine contraction in pregnant rats, which is thought
to be mediated by the EP3 receptor subtype. The structure–activity relationships (SARs) are also
discussed.
Received 9 November 2009
Revised 19 December 2009
Accepted 30 December 2009
Available online 4 January 2010
Keywords:
EP3 receptor
Antagonist
Ó 2010 Elsevier Ltd. All rights reserved.
Uterine contraction
1. Introduction
antagonist. Compound 2 showed significantly more potent antago-
nist activity relative to 1, while 2 showed nearly equipotent activ-
Prostaglandin E2 (PGE2), which plays important roles in numer-
ous physiological actions, has been known as the most widely dis-
tributed prostanoid in the living body. It has been demonstrated
that these various biological actions are mediated by the four
receptor subtypes, namely EP1, EP2, EP3, and EP4.1 Since a large
number of studies using EP1-4 knockout mice have made signifi-
cant contributions toward understanding their accessibility as
new therapeutic targets, the discovery of subtype selective ligands
has renewed interest for medicinal chemists in the field. In addi-
tion, clinical trials for several selective ligands including ONO-
8539 (ONO, EP1 antagonist),2 ONO-8815 (ONO, EP2 agonist),3
CP-533536 (Pfizer, EP2 agonist),4 DG-041 (de CODE, EP3 antago-
nist),5 ONO-4819 (ONO, EP4 agonist),6 RQ-00000007 (RaQualia,
EP4 antagonist),7 and BGC20-1531 (BTG, EP4 antagonist)8 have
also been reported. Among them, the EP3 antagonist, DG-041,
has been clinically tested for the treatment of peripheral occupied
arterial disease (PAOD).
ity relative to 1 in its in vivo evaluation. This inconsistency
between in vitro and in vivo data was considered to be mainly
due to the pharmacokinetic profiles of
1 (F = 31%) and 2
(F = 3.9%). In this paper, we report the further optimization of 1
to improve its in vitro and in vivo potencies as a potent and selec-
tive EP3 antagonist.
2. Chemistry
Synthesis of test compounds listed in Tables 2 and 3 is outlined
in Schemes 1–8.
A series of 1-phenyl-3-methylbutylamines were synthesized as
described in Schemes 1–4. Amines 59a–h were synthesized as
shown in Scheme 1. Reaction of t-butyl magnesium chloride (53)
with gaseous sulfur dioxide provided sulfinic acid 54. Reaction of
54 with thionyl chloride followed by the addition of aqueous
ammonia afforded sulfinamide 55.10 Dehydrative condensation of
55 with benzaldehydes 56a–h afforded sulfinimines 57a–h,
respectively. Nucleophilic addition reaction of 2-methylpropenyl-
magnesium chloride to 57a–h afforded the corresponding sulfina-
mides 58a–h, respectively. Catalytic hydrogenation of 58a–h
followed by acidic deprotection resulted in 59a–h as their respec-
tive hydrochlorides.
In our previous paper,9 we reported the discovery of 3-(2-ami-
nocarbonyl-4-phenoxymethylphenyl)propanoic acid analogs 1 and
2 (Table 1) as new chemical leads of a potent and selective EP3
* Corresponding author. Tel.: +81 75 961 1151; fax: +81 75 962 9314.
E-mail address: m.asada@ono.co.jp (M. Asada).
0968-0896/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmc.2009.12.068

1642
M. Asada et al. / Bioorg. Med. Chem. 18 (2010) 1641–1658
Table 1
Activity and pharmacokinetic profiles of 1 and 2
COOH
O
O
1 Ar =
2 Ar =
HN
Ar
*
*
Compound
In vitro EP3 activitya
In vivo efficacyc
PK profiles in rats
Cmax g/mL)
Binding
Function
%inh.
(3 mg/kg id)
CLtot
(mL/min/kg)
(l
F (%)
b
Ki (nM)
IC50 (nM)
at 10 mg/kg po
1
2
0.70
0.34
68
2.0
71%
83%
15.3
16.0
2.66
0.28
31
3.9
a
b
c
Mouse EP3 receptor was used.
EP3 antagonist activity was evaluated in the presence of 1% BSA.
In vivo efficacy was evaluated as % inhibition against the PGE2-induced uterine contraction in pregnant rats.
O
O
S
O
S
d
O
e
a
b, c
MgCl
S
N
S
N
OH
NH2
R
R
H
53
54
55
57a-h
58a-h
f, g
a R = 4-Me
b R = 2-F
c R = 4-F
d R = 3-Me, 4-Me
e R = 3-OMe, 4-OMe
g R = 3-F, 4-CF3
h R = 3-F, 5-CF3
NH+3 Cl
R
f
R = 3-F, 4-F
59a-h
Scheme 1. Synthesis of 59a–h. Reagents: (a) SO2, Et2O; (b) SOCl2, CH2Cl2; (c) NH3aq, THF; (d) benzaldehydes 56a–h, PPTS, MgSO4, CH2Cl2; (e) 2-methylpropenylmagnesium
chloride, THF; (f) H2, PtO2, MeOH; (g) HCl–dioxane, MeOH.
b
c, d
a
O
CHO
O
N
NH+3 Cl
N
R
R
H
60
61
63a-n
64a-n
a
b
c
R = 2-Me
R = 3-Me
R = 2-OMe
d
e
f
R = 3-OMe
R = 3-F
m R = 3-F, 4-OMe
R = 3-F, 5-F
g
h
i
R = 4-CF
3
R = 3-Me, 4-OMe
R = 3-Me, 4-F
j
k
l
R = 3-Me, 5-Me
n
R = 3,4-OCH CH O-
2
2
R = 3-CF
R = 3-F, 4-Me
3
Scheme 2. Synthesis of 64a–n. Reagents: (a) O-benzylhydroxylamine hydrochloride, MgSO4, CH2Cl2; (b) aryl bromides 62a–n, n-BuLi, BF3ꢀOEt2, THF; (c) H2, Pd–C, MeOH; (d)
HCl–dioxane, EtOAc.
Br
a
d, e
a
b
c
R = 3-Cl
R = 4-Cl
R = 3-Cl, 4-F
R
X
NH+3 Cl
R
R
65a-c
69a-c
66a-c X = OH
67a-c X = Br
68a-c X = N3
b
c
Scheme 3. Synthesis of 69a–c. Reagents: (a) n-BuLi, isovaleraldehyde (60), THF; (b) PBr3, CH2Cl2; (c) NaN3, DMF; (d) Ph3P, THF, H2O; (e) HCl–dioxane.
Synthesis of amines 64a–n is described in Scheme 2. A common
intermediate 61 was prepared by a dehydrative condensation of
isovaleraldehyde (60) with O-benzylhydroxylamine hydrochloride
in the presence of magnesium sulfate. Lithiation of aryl bromides

M. Asada et al. / Bioorg. Med. Chem. 18 (2010) 1641–1658
1643
O
CN
a
e
b
X
NH2
O
O
O
O
70
71
75
72 X = OH
c
73 X = Cl
d
74 X = N 3
Scheme 4. Synthesis of 75. Reagents: (a) isobutylmagnesium chloride, THF then HClaq; (b) NaBH4, MeOH; (c) MsCl, LiCl, Et3N, THF; (d) NaN3, DMF; (e) Ph3P, THF, H2O.
O
O
c
O
O
d
a
O
O
Y
OAc
O
X
O
76 X = Me
80 Y = OAc
81 Y = OH
82 Y = OTf
79
a
b
e
f
77 X =
Br
*
g
78 X =
83 Y = COOH
O
*
O
O
OH
O
O
h
b
NO2
O
O2N
85
O
84
O
COOH
O
O
i, j
R
c
85
+
HN
NH+3 Cl
R
64a R = 2-Me
64b R = 3-Me
64c R = 2-OMe
64d R = 3-OMe
59b R = 2-F
64e R = 3-F
69a R = 3-Cl
69b R = 4-Cl
64i R = 3-Me, 4-F
64j R = 3-Me, 5-Me
3-4, 6-7, 9-10, 12-16,
18-19 and 21-28
64k R = 3,4-OCH CH O-
2
2
64l R = 3-F, 4-Me
64m R = 3-F, 4-OMe
59f R = 3-F, 4-F
59g R = 3-F, 4-CF3
64n R = 3-F, 5-F
59h R = 3-F, 5-CF3
69c R = 3-Cl, 4-F
64f R = 3-CF
3
64g R = 4-CF
3
59d R = 3-Me, 4-Me
Scheme 5. Synthesis of 3–4, 6–7, 9–10, 12–16, 18–19, and 21–28. Reagents: (a) NBS, AIBN, CCl4; (b) phenol, NaH, DMF; (c) t-BuOK, THF then AcCl; (d) NaBH4, NiCl2ꢀ6H2O,
THF, MeOH; (e) K2CO3, MeOH; (f) Tf2O, pyridine, CH2Cl2; (g) CO, Pd(OAc)2, DPPF, KOAc, DMF; (h) 83, EDCꢀHCl, DMAP, ClCH2CH2Cl; (i) i-Pr2NEt, ClCH2CH2Cl; (j) TFA, anisole,
CH2Cl2.
62a–n followed by the addition of 61 in the presence of boron tri-
fluoride etherate afforded 63a–n, respectively.11 Catalytic hydroge-
nation of 63a–n followed by treatment with hydrogen chloride
afforded 64a–n as their respective hydrochlorides.
Synthesis of amines 69a–c is outlined in Scheme 3. Lithiation
of aryl bromides 65a–c followed by the addition of isovaleralde-
hyde (60) afforded 66a–c, bromination of which with phosphoric
tribromide provided 67a–c. Substitution reaction of 67a–c with
sodium azide afforded 68a–c. Reduction of the azides 68a–c with
triphenylphosphine followed by the treatment with hydrogen
chloride produced amines 69a–c, as their respective
hydrochlorides.
Amine 75 was synthesized from 4-methoxybenzonitrile (70), as
shown in Scheme 4. Nucleophilic addition reaction of isobutylmag-
nesium chloride to 70 followed by the acidic treatment afforded
ketone 71. Sodium borohydride reduction of 71 provided 72. Reac-
tion of 72 with methanesulfonyl chloride in the presence of lithium
chloride and triethylamine afforded 73, substitution reaction of
which with sodium azide provided 74. Reduction of 74 with tri-
phenylphosphine resulted in 75.

1644
M. Asada et al. / Bioorg. Med. Chem. 18 (2010) 1641–1658
COOEt
COOEt
O
O
a
b
R
O
HN
+
NH+3 Cl
COOH
R
86
59a R = 4-Me
75 R = 4-OMe
59c R = 4-F
64h R = 3-Me, 4-OMe
59e R = 3-OMe, 4-OMe
87a R = 4-Me
87b R = 4-OMe
87c R = 4-F
87d R = 3-Me, 4-OMe
87e R = 3-OMe, 4-OMe
COOH
O
O
R
HN
5, 8, 11, 17 and 20
Scheme 6. Synthesis of 5, 8, 11, 17, and 20. Reagents: (a) EDCꢀHCl, HOBt, N-methylmorpholine, DMF; (b) NaOHaq, THF, MeOH.
COOMe
COOMe
h
e
d
MOMO
MOMO
X
A
OH
O
O
92 A = OH
93 A = OTf
77 X = Br
91
f
a
b
c
88 X = OAc
89 X = OH
g
94 A = COOH
90 X = OMOM
COOMe
COOH
COOMe
Y
O
O
O
O
O
k
l
R
R
HN
HN
HN
99a-s
95 Y = OMOM
96 Y = OH
29-41 and 47-52
i
j
97 Y = OMs
a R = 2-F
b R = 3-F
c R = 4-F
d R = 2-Cl
e R = 3-Cl
g R = 2-CN
h R = 3-CN
j
R = 2-Me
m R = 3-OMe
n R = 2-F, 3-F
o R = 2-F, 4-F
p R = 2-F, 5-F
q R = 2-F, 6-F
r R = 3-F, 4-F
s R = 3-F, 5-F
k R = 3-Me
R = 4-Me
f
R = 4-Cl
i
R = 4-CN
l
Scheme 7. Synthesis of 29–41 and 47–52. Reagents: (a) KOAc, DMF; (b) NaOHaq, THF, MeOH; (c) MOMCl, i-Pr2NEt, dichloroethane; (d) NaOMe, THF, MeOH; (e) NaBH4,
NiCl2ꢀ6H2O, THF, MeOH; (f) Tf2O, pyridine, CH2Cl2; (g) CO, Pd(OAc)2, DPPF, KOAc, DMF; (h) 64j, EDCꢀHCl, HOBt, N-methylmorpholine, DMF; (i) HCl–dioxane, MeOH; (j) MsCl,
Et3N, THF; (k) phenols 98a–s, NaH, DMF; (l) NaOHaq, THF, MeOH.
As shown in Scheme 5a–c, compounds 3–4, 6–7, 9–10, 12–16,
18–19, and 21–28 were synthesized using a polymer-supported
activated ester 85 as a key intermediate. Synthesis of the carbox-
ylic acid 83 is described in Scheme 5a. Bromination of 7-methyl-
coumarin (76) with N-bromosuccinimide in the presence of
azobisisobutyronitrile in carbon tetrachloride afforded 77. Substi-
tution reaction of the bromide 77 with sodium phenoxide provided
78. Ring-opening reaction of 78 with t-butoxide followed by the
treatment of the formed phenoxide with acetyl chloride afforded
79. 1,4-Reduction of the unsaturated ester 79 with sodium borohy-
dride in the presence of nickel chloride provided saturated ester
80,12 methanolysis of which provided 81. Trifluoromethanesulf-
onylation of the phenol 81 afforded 82, which was converted to
the carboxylic acid 83 by the palladium-catalyzed insertion reac-
tion of carbon monoxide. Dehydrative condensation of the nitro-
phenol resin 8413 with 83 afforded the nitrophenol ester resin 85
as shown in Scheme 5b. Aminolysis of 85 with amines 64a–d,
59b, 64e, 69a–b, 64f–g, 59d, 64i–m, 59f–g, 64n, 59h, and 69c fol-
lowed by acidic deprotection afforded analogs 3–4, 6–7, 9–10, 12–
16, 18–19, and 21–28, respectively, as shown in Scheme 5c.
As shown in Scheme 6, several analogs such as 5, 8, 11, 17, and
20 were derived from the previously reported carboxylic acid 86.9
Condensation reaction of 86 with amines 59a, 75, 59c, 64h, and
59e afforded 87a–e, respectively, alkaline hydrolysis of which
afforded the corresponding carboxylic acids 5, 8, 11, 17, and 20,
respectively.
Synthesis of 29–41 and 47–52 is described in Scheme 7. Substi-
tution reaction of the bromide 77 with potassium acetate afforded

M. Asada et al. / Bioorg. Med. Chem. 18 (2010) 1641–1658
1645
COOMe
c
COOMe
b
a
NC
CN
NC
O
O
OH
Y
O
X
O
101
102 Y = OH
103 Y = OTf
d
e
77 X =
Br
*
a
104 Y = COOH
100 X =
O
*
COOH
COOEt
NC
NC
O
O
O
O
f
g
R
R
104
b
HN
HN
+
NH+3 Cl
R
64b R = 3-Me
64d R = 3-OMe
59c R = 4-F
64i R = 3-Me, 4-F
59e R = 3-OMe, 4-OMe
42-46
105a R = 3-Me
105b R = 3-OMe
105c R = 4-F
105d R = 3-Me, 4-F
105e R = 3-OMe, 4-OMe
Scheme 8. Synthesis of 42–46. Reagents: (a) 3-cyanophenol, NaH, DMF; (b) NaOMe, THF, MeOH; (c) NaBH4, NiCl2ꢀ6H2O, THF, MeOH; (d) Tf2O, pyridine, CH2Cl2; (e) CO,
Pd(OAc)2, DPPF, KOAc, DMF; (f) EDCꢀHCl, HOBt, N-methylmorpholine, DMF; (g) NaOHaq, THF, MeOH.
88, alkaline hydrolysis of which provided 89. Protection of the
formed hydroxy group of 89 as a methoxymethyl ether afforded
90, ring-opening reaction of which resulted in methyl acrylate
91. Sodium borohydride reduction of 91 in the presence of nickel
chloride afforded saturated ester 92,12 which was converted to
the carboxylic acid 94 in the same manner as described for 83.
Condensation of 94 and 1-(3,5-dimethylphenyl)-3-methylbutyl-
amine hydrochloride (64j) afforded carboxyamide 95, acidic depro-
tection of which provided benzyl alcohol 96. Methanesulfonylation
of 96 gave 97, substitution reaction of which with sodium phenox-
ides derived from the commercially available phenols 98a–s affor-
ded the corresponding phenoxyethers 99a–s, respectively. Alkaline
hydrolysis of 99a–s produced the corresponding carboxylic acids
29–41 and 47–52, respectively.
Table 2
Effect of the substituent on the benzene ring of the carboxyamide side chain on
activity profiles
COOH
5
6
O
O
4
R
3
HN
2
Compound
R
In vitro EP3 activitya
b
Binding Ki (nM)
Function IC50 (nM)
4-(3-Cyanophenoxymethylphenyl)propanoic acid analogs 42–
46 were synthesized as shown in Scheme 8. Substitution reaction
of the bromide 77 with sodium 3-cyanophenoxide resulted in
100, which was converted to carboxylic acid 104 by the same pro-
cedures as described above. Condensation reaction of 104 with 3-
methyl-1-phenylbutylamines 64b, 64d, 59c, 64i, and 59e gave
carboxyamides 105a–e, respectively, alkaline hydrolysis of which
produced the corresponding carboxylic acids 42–46, respectively.
1
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
H
0.70
0.94
0.30
0.63
1.2
0.13
0.36
1.4
0.20
0.93
0.18
0.28
0.39
0.76
0.17
0.16
0.16
0.19
0.50
0.44
0.20
0.14
0.40
0.70
0.30
0.45
0.26
68
230
37
51
190
21
59
130
40
20
35
51
39
32
16
11
18
17
24
19
67
42
47
53
19
15
25
2-Me
3-Me
4-Me
2-OMe
3-OMe
4-OMe
2-F
3-F
4-F
3-Cl
4-Cl
3-CF3
4-CF3
3-Me, 4-Me
3-Me, 4-OMe
3-Me, 4-F
3-Me, 5-Me
3-OMe, 4-OMe
3,4-(–OCH2CH2O–)
3-F, 4-Me
3-F, 4-OMe
3-F, 4-F
3. Results and discussion
Test compounds listed in Tables 2 and 3 were biologically eval-
uated for their inhibition of the specific binding of a radiolabeled
ligand, [3H]PGE2 to membrane fractions prepared from cells stably
expressing mouse EP1, EP2, EP3
tor antagonist activity was determined by a Ca2+ assay using
mouse EP3 receptors expressed on CHO cells in the presence of
a, or EP4 receptor. The EP3 recep-
a
1% bovine serum albumin (BSA).
In our previous paper,9 we reported the discovery of 3-(2-ami-
nocarbonyl-4-phenoxymethylphenyl)propanoic acids 1 and 2 as
new chemical leads for a selective EP3 receptor antagonist. Among
them, N-benzylcarboxyamide analog 1 was selected as a new
chemical lead for further optimization because of its superior PK
profiles relative to 2. To optimize the benzene ring of the carboxy-
amide side chain of 1, polymer-supported activated ester was used
3-F, 4-CF3
3-F, 5-F
3-F, 5-CF3
3-Cl, 4-F
a
Mouse EP3 receptor was used.
EP3 antagonist activity was evaluated in the presence of 1% BSA.
b

1646
M. Asada et al. / Bioorg. Med. Chem. 18 (2010) 1641–1658
Table 3
the same trend as the binding affinity as exemplified by 11. Evalu-
ation of the binding affinity (Ki values) was carried out in the ab-
sence of BSA, while the evaluation of the antagonist activity (IC50
values) was carried out in the presence of 1% BSA to estimate more
exact in vivo potency. Compound 10 was functionally 200-fold
weaker than its Ki value in the presence of 1% BSA, while com-
pound 11 was functionally only 21-fold weaker than its Ki value.
The same tendency was also observed in 1 and 2, as shown in
Table 1. We estimate that these relationships between the Ki values
and the IC50 values are mainly due to the different potencies of
their protein-binding characteristic resulting from the structural
features such as basicity and acidity, lipophilicity and hydrophilic-
ity, and three-dimensional structure. Presumed protein binding in
an in vivo evaluation has been known as one of the important fac-
tors to give an influence on the in vivo efficacy of a drug. For such a
reason, the antagonist activity was assessed in the presence of BSA.
Unfortunately, 2-substituted phenyl analogs 3, 6, and 9 did not
show a significant improvement in either binding affinity or antag-
onist activity relative to others in each of the series. This may be
the result of an unfavorable steric interaction between the intro-
duced substituent at the 2-position and an adjacent isobutyl group.
Based on the above-described information, chlorophenyl analogs
12–13 and trifluoromethylphenyl analogs 14–15 were synthesized.
3-Chlorophenyl analog 12 was more potent than 4-chlorophenyl
analog 13. 3-Trifluoromethylphenyl analog 14 was equipotent to
4-trifluoromethylphenyl analog 15 in terms of its EP3 antagonist
activities.
Effect of the substituent on the benzene ring of the phenoxymethyl side chain on
activity profiless
COOH
5
6
3
6
O
5
2
O
4
R.
R1
.
HN
2
3
4
2
Compound
R1
R2
In vitro EP3 activitya
b
Binding Ki
(nM)
Function IC50
(nM)
19
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
3-Me, 5-Me
3-Me, 5-Me
3-Me, 5-Me
3-Me, 5-Me
3-Me, 5-Me
3-Me, 5-Me
3-Me, 5-Me
3-Me, 5-Me
3-Me, 5-Me
3-Me, 5-Me
3-Me, 5-Me
3-Me, 5-Me
3-Me, 5-Me
3-Me, 5-Me
3-Me
H
2-F
3-F
4-F
2-Cl
3-Cl
4-Cl
2-CN
3-CN
4-CN
2-Me
3-Me
4-Me
0.19
0.10
0.13
0.25
0.090
0.21
0.62
0.35
0.12
0.46
0.17
0.11
0.67
0.27
0.20
0.13
0.17
0.20
0.67
0.15
0.19
0.10
1.3
17
13
15
5.4
8.3
3.8
30
9.4
3.9
16
3.9
4.2
16
3.2
6.6
3.2
7.1
2.8
3.7
3.6
6.0
7.0
59
3-OMe
3-CN
3-OMe
3-CN
3-CN
3-CN
3-CN
4-F
Introduction of two substituents into the benzene ring of the
carboxyamide side chain was also carried out to afford 16–28.
Among them, 3,4-dimethylphenyl analog 16, 4-methoxy-3-meth-
ylphenyl analog 17, 4-fluoro-3-methylphenyl analog 18, 3,5-
dimethylphenyl analog 19, 3,4-ethylenedioxyphenyl analog 21,
3,5-difluorophenyl analog 26, and 3-fluoro-5-trifluoromethyl-
phenyl analog 27 exhibited equivalent or more potent antagonist
activities relative to any other mono-substituent analogs including
7 and 11 regardless of their binding affinity.
3-Me, 4-F
3-OMe, 4-OMe
3-Me, 5-Me
3-Me, 5-Me
3-Me, 5-Me
3-Me, 5-Me
3-Me, 5-Me
3-Me, 5-Me
2-F, 3-F
2-F, 4-F
2-F, 5-F
2-F, 6-F
3-F, 4-F
3-F, 5-F
0.34
0.19
5.7
10
a
Mouse EP3 receptor was used.
EP3 antagonist activity was evaluated in the presence of 1% BSA.
b
Using some of the optimized N-benzylcarboxyamide analogs
such as 4, 7, 11, and 18–20, further chemical modification of their
phenoxymethyl side chain was carried out as described in Table 3.
Replacement of the phenoxy moiety of 19 with 2-fluorophenoxy,
3-fluorophenoxy, or 4-fluorophenoxy afforded 29–31, all with
equipotent binding affinity. The 4-fluorophenoxy analog 31 was
more potent in terms of antagonist activity than 29 and 30. Further
optimization of the substituents provided chlorophenoxy analogs
32–34, cyanophenoxy analogs 35–37, and methylphenoxy analogs
38–40. Among them, 3-chlorophenyl analog 33, 3-cyanophenyl
analog 36, and 2-methyl analog 38 showed improved antagonist
activity with an IC50 value of 3.8, 3.9, and 3.9 nM, respectively.
However, 4-substituted phenyl analogs 34, 37, and 40 tended to
exhibit reduced potency in terms of both the binding affinity and
the antagonist activity relative to the others. 3-Methoxyphenyl
analog 41 had equipotent binding affinity and more potent antag-
onist activity relative to 19. Because of the lower c log P value of
3-cyanophenoxy analog 36 relative to that of 19, replacement of
the phenoxy moiety of 4, 7, 11, 18, and 20 with a 3-cyanophenoxy
moiety afforded 42–46, respectively, with retention of the potent
binding affinity. All these substitutions produced compounds with
2.8–6.6-fold more potent antagonist activities relative to their
unsubstituted analogs. Further efforts to explore the optimum
substituents of the phenoxy moiety resulted in a series of difluoro-
phenoxy analogs 47–52 because substitution of the phenoxy
moiety with electron-withdrawing fluorine atoms was considered
to be effective on the predicted oxidative metabolism. All analogs
except 50 exhibited more potent antagonist activities relative to
19. 2,6-Difluorophenoxy analog 50 showed a significant reduction
in both binding affinity and antagonist activity. This significant
Table 4
In vivo efficacy of 18, 19, 30, 36, 38, and 49
Compound
In vivo efficacy (%inh., id)a
0.1 mg/kg (%)
0.3 mg/kg (%)
1 mg/kg (%)
18
19
30
36
38
49
NTb
NTb
NTb
NTb
NTb
48
31
28
66
55
62
93
73
73
84
95
83
98
a
In vivo efficacy was evaluated as %inhibition against the PGE2-induced uterine
contraction in pregnant rats.
b
Not tested.
as an intermediate. Further chemical modification of the benzene
ring of the 4-phenoxymethyl moiety was also easily carried out be-
cause of the readily available substituted phenols.
Effect of the substituent on the benzene ring of the carboxyam-
ide side chain was investigated as shown in Table 2. Introduction of
a methyl group into the benzene ring afforded 3–5. Among them,
3-methylphenyl analog 4 was more potent than 3 and 5. Methoxy-
phenyl analogs 6–8 and fluorophenyl analogs 9–11 were also syn-
thesized and evaluated for their binding affinity and antagonist
activity. Again 3-substituted phenyl analogs 7 and 10 were more
potent in terms of their binding affinity than others in each of
the series, although the antagonist activity did not always follow

M. Asada et al. / Bioorg. Med. Chem. 18 (2010) 1641–1658
1647
Table 5
Pharmacokinetic profiles of 30 and 49 in rats
Compound
Route
Dose
AUC (
l
g h/mL)
t1/2 (h)
CLtot (mL/min/kg)
45.2
Vss (L/kg)
Cmax
0.39
0.52
(l
g/mL)
F (%)
30
iv
po
1.2
13
0.44
1.09
1.5
1.9
1.32
23
19
49
iv
po
1.2
11
0.47
0.85
2.1
5.4
44.5
1.43
reduction in potency for 50 may indicate a deleterious effect of the
2,6-disubstituted phenoxy moiety on the activity profile.
4. Conclusion
Compounds 18, 19, 30, 36, 38, and 49, all of which showed rel-
atively potent binding affinity and/or antagonist activity, were se-
lected for in vivo evaluation. After intraduodenal dosing, they were
evaluated for their inhibitory effect against the PGE2-induced uter-
ine contraction in pregnant rats, which is thought to be mediated
by the EP3 receptor subtype.14 These results are summarized in
Table 4. Compounds 18 and 19, which had nearly equipotent
invitroactivities,showednearlyequipotentinvivoefficacyatdosages
of 0.3 mg/kg and 1 mg/kg. Their in vivo potencies were threefold
more potent than that of 1, which was the original lead compound.
Compound 30, which showed nearly equipotent in vitro activity to
18 and 19, exhibited an increased in vivo efficacy relative to 18 and
19 at dosages of 0.3 mg/kg and 1 mg/kg. Compounds 36 and 38
also showed more potent in vivo efficacy than 18 and 19 at similar
dosages. Although compound 49 showed slightly reduced potency
in terms of antagonist activity relative to 36 and 38, it was found to
exhibit the most potent in vivo efficacy (48% inhibition at 0.1 mg/
kg, 93% inhibition at 0.3 mg/kg, and 98% inhibition at 1 mg/kg) in a
dose-dependent manner among the tested compounds. Among the
compounds tested for the in vivo efficacy, 3-fluorophenoxy analog
30 and 2,5-difluorophenoxy analog 49 were evaluated for their
pharmacokinetic profiles in rats as shown in Table 5. Total clear-
ance (CLtot) of 30 and 49 was larger than that of 1 and 2, while
the bioavailability (F) of 30 and 49 was lower than that of 1 and
higher than that of 2. The maximum concentration (Cmax) of 49
was lower than that of 1 and slightly higher than that of 2, while
the maximum concentration (Cmax) of 30 was close to that of 2.
Thus, these two analogs showed improved PK profiles in the max-
imum concentration (Cmax) and bioavailability (F) relative to 2,
with potent EP3 antagonist activity. This was the plausible reason
for their increased in vivo efficacy.
Using 3-(2-aminocarbonylphenyl)propanoic acid analog 1 as a
scaffold, further optimization was carried out to improve in vitro
and in vivo potencies. Chemical modification was focused on the
two phenyl moieties of 1. In most cases, introduction of one or
two substituents into the benzene ring of the carboxyamide side
chain resulted in the tendency to increase the in vitro activity rel-
ative to the unsubstituted phenyl analog 1. An ortho-substitution,
which is illustrated by compounds 3, 6, and 9, did not improve
the potency of the EP3 binding affinity and antagonist activity. Fur-
ther chemical modification of another phenyl moiety of 4, 7, 11,
and 18–20 was carried out. Most of the compounds listed in Table 3
had improved antagonist activity relative to those of their corre-
sponding unsubstituted phenoxymethyl analogs. Several com-
pounds were evaluated for their inhibitory effect against the
PGE2-induced uterine contraction in pregnant rats. Among them,
compound 49 possessing excellent subtype selectivity exhibited
the most potent in vivo efficacy among the tested compounds with
a 10-fold higher potency relative to 1. Further investigation involv-
ing the synthesis of optically active forms and evaluation of their
activity profiles will be disclosed elsewhere.
5. Experimental
5.1. Chemistry
5.1.1. General procedures
Analytical samples were homogeneous as confirmed by TLC,
and afforded spectroscopic results consistent with the assigned
structures. Proton nuclear magnetic resonance spectra (1H NMR)
were taken on a Varian Mercury 300 spectrometer, Varian GEM-
INI-200, or VXR-200s spectrometer using deuterated chloroform
(CDCl3), deuterated dimethylsulfoxide (DMSO-d6), or deuterated
methanol (CD3OD) as the solvent. Fast atom bombardment mass
spectra (FAB-MS, HRMS) and electron ionization (EI) were obtained
on a JEOL JMS-DX303HF spectrometer. Atmospheric pressure
The binding profiles of 18, 19, 30, 36, 38, and 49 for EP1-4
receptor subtypes were also evaluated as shown in Table 6. None
had appreciable binding affinity for EP1 and EP2 receptors with
Kis >10,000 nM, while they had moderate binding affinity for the
EP4 receptor and sub-nanomolar binding affinity for the EP3 recep-
tor. Thus, these compounds were potent and selective EP3 antago-
nists with in vivo efficacy.
chemical ionization (APCI) was determined on
a HITACHI
MI200H spectrometer. Infrared spectra (IR) were measured in a
Perkin–Elmer FT-IR 1760X spectrometer. Melting points and
results of elemental analyses were uncorrected. Column chroma-
tography was carried out on silica gel [Merck Silica Gel 60
(0.063–0.200 mm), Wako gel C-200, or Fuji Silysia FL60D]. Thin
layer chromatography was performed on silica gel (Merck TLC or
HPTLC plates, Silica Gel 60 F254). The following abbreviations for
solvents and reagents are used; t-butylmethylether (TBME), dieth-
ylether (Et2O), N,N-dimethylformamide (DMF), dimethylsulfoxide
(DMSO), ethanol (EtOH), ethyl acetate (EtOAc), methanol (MeOH),
tetrahydrofuran (THF), azobisisobutylonitrile (AIBN), 1,10-bis-
Table 6
Subtype selectivity of 18, 19, 30, 36, 38, and 49
Compound
Binding affinity Kia (nM)
EP1
EP2
EP3
EP4
630
780
190
77
18
19
30
36
38
49
>10,000
>10,000
>10,000
>10,000
>10,000
>10,000
>10,000
>10,000
>10,000
>10,000
>10,000
>10,000
0.16
0.19
0.13
0.12
0.17
0.10
(diphenylphosphino)ferrocene
(DPPF),
N-bromosuccinimide
(NBS), diisopropylethylamime (DIPEA), N,N-dimethyl-4-aminopyr-
idine (DMAP), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide
hydrochloride (EDCꢀHCl), 1-hydroxybenzotriazole (HOBt), meth-
anesulfonyl chloride (MsCl), pyridinium p-toluenesulfonate (PPTS),
1200
230
a
Mouse EP1-4 receptors were used.

1648
M. Asada et al. / Bioorg. Med. Chem. 18 (2010) 1641–1658
triethylamine (TEA), and trifluoromethanesulfonic anhydride
(Tf2O).
5.1.6. 1-(4-Fluorophenyl)-3-methylbutan-1-amine
hydrochloride (59c)
The titled compound was synthesized in the same manner as
described for 59a using 56c instead of 56a as a white powder. Yield
50% from 55; 1H NMR (300 MHz, CD3OD) d 7.54–7.45 (m, 2H),
7.26–7.16 (m, 2H), 4.34 (dd, J = 9.9, 5.7 Hz, 1H), 1.98–1.87 (m,
1H), 1.84–1.72 (m, 1H), 1.47–1.30 (m, 1H), 0.95 (d, J = 6.6 Hz,
3H), 0.92 (d, J = 6.6 Hz, 3H).
5.1.2. 2-Methylpropane-2-sulfinic acid (54)
A solution of t-butylmagnesium chloride (53) (2 M in Et2O,
100 mL, 0.200 mol) in Et2O (100 mL) was cooled with ice-bath
and then sulfur dioxide gas was bubbled into the solution for 2 h
below 10 °C. Excess sulfur dioxide gas was removed under reduced
pressure and then aqueous NH4Cl was added. The resultant white
precipitate was removed by filtration and the filtrate was saturated
with NaCl and then extracted with EtOAc. The organic layer was
washed with brine, dried over MgSO4, and concentrated in vacuo
to yield 54 (9.90 g, 41%) as a white solid. 1H NMR (300 MHz, CDCl3)
d 10.4 (br s, 1H), 1.18 (s, 9H).
5.1.7. 1-(3,4-Dimethylphenyl)-3-methylbutan-1-amine
hydrochloride (59d)
The titled compound was synthesized in the same manner as
described for 59a using 56d instead of 56a as a white powder. Yield
43% from 55; 1H NMR (300 MHz, CD3OD) d 7.23–7.08 (m, 3H), 4.21
(dd, J = 10, 5.7 Hz, 1H), 2.30 (s, 3H), 2.28 (s, 3H), 1.97–1.83 (m, 1H),
1.78–1.67 (m, 1H), 1.47–1.29 (m, 1H), 0.94 (d, J = 6.9 Hz, 3H), 0.91
(d, J = 6.9 Hz, 3H).
5.1.3. 2-Methylpropane-2-sulfinamide (55)
To a stirred solution of 54 (5.00 g, 41.4 mmol) in CH2Cl2 (50 mL)
was added dropwise thionyl chloride (6.20 mL, 82.8 mmol) at 0 °C
under argon atmosphere. After being stirred for 20 min, the reac-
tion mixture was diluted with toluene (150 mL) and then evapo-
rated to approximately one-fourth volume. The resultant solution
was diluted with THF (100 mL) and was then added dropwise to
aqueous NH3 (28%, 200 mL) in THF (200 mL) at 0 °C. After being
stirred for 15 min, the reaction mixture was saturated with NaCl
and then extracted with EtOAc. The organic layer was washed with
brine, dried over MgSO4, and concentrated in vacuo to yield 55
(3.20 g, 64% in two steps) as a brown solid. 1H NMR (300 MHz,
CDCl3) d 3.81 (br s, 2H), 1.18 (s, 9H).
5.1.8. 1-(3,4-Dimethoxyphenyl)-3-methylbutan-1-amine
hydrochloride (59e)
The titled compound was synthesized in the same manner as
described for 59a using 56e instead of 56a as a brown powder.
Yield 57% from 55; 1H NMR (300 MHz, CD3OD) d 7.06–6.97 (m,
3H), 4.26 (dd, J = 10, 5.6 Hz, 1H), 3.85 (s, 3H), 3.83 (s, 3H), 1.98–
1.86 (m, 1H), 1.80–1.68 (m, 1H), 1.49–1.33 (m, 1H), 0.96 (d,
J = 6.6 Hz, 3H), 0.92 (d, J = 6.6 Hz, 3H).
5.1.9. 1-(3,4-Difluorophenyl)-3-methylbutan-1-amine
hydrochloride (59f)
5.1.4. 3-Methyl-1-(4-methylphenyl)butan-1-amine
hydrochloride (59a)
The titled compound was synthesized in the same manner as
described for 59a using 56f instead of 56a as a gray powder. Yield
53% from 55; 1H NMR (300 MHz, DMSO-d6) d 8.40 (br s, 3H), 7.74–
7.62 (m, 1H), 7.59–7.47 (m, 1H), 7.43–7.32 (m, 1H), 4.30 (t,
J = 7.5 Hz, 1H), 1.82–1.64 (m, 2H), 1.37–1.18 (m, 1H), 0.87 (d,
J = 6.6 Hz, 3H), 0.83 (d, J = 6.6 Hz, 3H).
A solution of 55 (500 mg, 4.10 mmol), 56a (1.48 g, 12.4 mmol),
PPTS (52 mg, 0.205 mmol), and MgSO4 (2.50 g, 20.5 mmol) in
dichloroethane (6 mL) was stirred for 12 h at room temperature
under argon atmosphere. The reaction mixture was filtrated and
the filtrate was concentrated in vacuo to afford 57a, which was
used for the next step without purification. To a stirred solution
of 57a in CH2Cl2 (15 mL) was added dropwise 2-methylpropenyl
magnesium chloride (0.5 M in Et2O, 35 mL, 17.5 mmol) at 0 °C un-
der argon atmosphere. After being stirred for 30 min, the reaction
was quenched with water and then the reaction mixture was ex-
tracted with EtOAc. The organic layer was washed with water
and brine, dried over MgSO4, and concentrated in vacuo. The resul-
tant residue was passed through a short-pass column chromatog-
raphy to remove less polar impurities. The resultant residue was
diluted with MeOH (5 mL) and then PtO2 (300 mg) was added.
The suspension was stirred for 12 h under hydrogen atmosphere.
The reaction mixture was filtered through a pad of Celite and the
filtrate was concentrated in vacuo. The resultant residue was di-
luted with MeOH (4 mL) and then 4 M HCl in dioxane (4 mL) was
added at room temperature. After being stirred for 1 h, the reaction
mixture was concentrated in vacuo. The resultant residue was
washed with EtOAc–hexane to afford 59a (135 mg, 13% from 55)
as a white powder. 1H NMR (300 MHz, DMSO-d6) d 8.43 (br s,
3H), 7.47 (d, J = 7.8 Hz, 2H), 7.33 (d, J = 7.8 Hz, 2H), 4.27 (m, 1H),
2.40 (s, 3H), 1.88–1.76 (m, 2H), 1.35 (m, 1H), 0.95 (d, J = 6.6 Hz,
3H), 0.91 (d, J = 6.3 Hz, 3H).
5.1.10. 1-[3-Fluoro-4-(trifluoromethyl)phenyl]-3-methylbutan-
1-amine hydrochloride (59g)
The titled compound was synthesized in the same manner as
described for 59a using 56g instead of 56a as a white powder. Yield
19% from 55; 1H NMR (300 MHz, CD3OD) d 7.59 (dd, J = 8.4, 7.8 Hz,
1H), 7.41 (dd, J= 10, 2.0 Hz, 1H), 7.33–7.27 (m, 1H), 4.38 (dd, J = 9.8,
6.2 Hz, 1H), 1.97–1.72 (m, 2H), 1.48–1.32 (m, 1H), 0.96 (d,
J = 6.6 Hz, 3H), 0.93 (d, J = 6.6 Hz, 3H).
5.1.11. 1-[3-Fluoro-5-(trifluoromethyl)phenyl]-3-methylbutan-
1-amine hydrochloride (59h)
The titled compound was synthesized in the same manner as
described for 59a using 56h instead of 56a as a white powder.
Yield 31% from 55; 1H NMR (300 MHz, CD3OD) d 7.67 (s, 1H),
7.59 (s, 1H), 7.56 (s, 1H), 4.50 (dd, J = 9.3, 6.5 Hz, 1H), 1.97–1.75
(m, 2H), 1.50–1.32 (m, 1H), 0.98 (d, J = 6.6 Hz, 3H), 0.94 (d,
J = 6.6 Hz, 3H).
5.1.12. 3-Methylbutanal O-benzyloxime (61)
A solution of 60 (20.0 g, 0.232 mol) and O-benzylhydroxyl-
amine hydrochloride (37.1 g, 0.232 mol) in pyridine (500 mL)
was stirred for 2 h at 80 °C under argon atmosphere. The reac-
tion mixture was concentrated in vacuo and then diluted with
EtOAc. The solution was washed with 1 M HCl, water and brine,
dried over MgSO4 and concentration in vacuo to yield 61 (44.3 g,
quant., E,Z mixture) as a colorless oil. 1H NMR (300 MHz, CDCl3)
d 7.44 (d, J = 6.9 Hz, 0.58H), 7.39–7.24 (m, 5H), 6.72 (d, J = 6.9 Hz,
0.42H), 5.10 (s, 0.84H), 5.07 (s, 1.16H), 2.28 (m, 1H), 2.05 (m,
1H), 1.82 (m, 1H), 0.98 (d, J = 6.6 Hz, 3H), 0.96 (d, J = 6.6 Hz,
3H).
5.1.5. 1-(2-Fluorophenyl)-3-methylbutan-1-amine
hydrochloride (59b)
The titled compound was synthesized in the same manner as
described for 59a using 56b instead of 56a as a brown powder.
Yield 55% from 55; 1H NMR (300 MHz, CD3OD) d 7.55–7.42 (m,
2H), 7.35–7.17 (m, 2H), 4.62 (dd, J = 9.9, 6.0 Hz, 1H), 2.03–1.89
(m, 1H), 1.87–1.75 (m, 1H), 1.49–1.33 (m, 1H), 0.96 (d, J = 6.6 Hz,
3H), 0.93 (d, J = 6.6 Hz, 3H).

M. Asada et al. / Bioorg. Med. Chem. 18 (2010) 1641–1658
1649
5.1.13. 3-Methyl-1-(2-methylphenyl)butan-1-amine
hydrochloride (64a)
5.1.19. 3-Methyl-1-[4-(trifluoromethyl)phenyl]butan-1-amine
hydrochloride (64g)
To a stirred solution of 62a (2.14 g, 12.5 mmol) in THF (30 mL)
was added dropwise n-BuLi (1.59 M in hexane, 7.90 mL,
12.5 mmol) at ꢁ70 °C under argon atmosphere and then the mix-
ture was stirred for 1.5 h at ꢁ70 °C. To the resultant mixture were
added dropwise 61 (800 mg, 4.18 mmol) in toluene (30 mL) and
successively BF3ꢀOEt2 1.59 mL (12.5 mmol) at ꢁ70 °C. After being
stirred for 2 h at ꢁ70 °C, the reaction was quenched with water
and then the reaction mixture was extracted with EtOAc. The or-
ganic layer was washed with water and brine, dried over MgSO4,
and concentrated in vacuo. The resultant residue was diluted with
MeOH (20 mL) and then Pd/C (10% wet, 100 mg) was added. The
suspension was stirred for 12 h under hydrogen atmosphere. The
Pd/C was removed by filtration through a pad of Celite and the fil-
trate was concentrated in vacuo. The resultant residue was dis-
solved in EtOAc (20 mL) and then treated with 4 M HCl in
dioxane (10 mL). After concentration in vacuo, the resultant solid
was washed with EtOAc to yield 64a (107 mg, 12% from 61) as a
white powder. 1H NMR (300 MHz, CD3OD) d 7.46–7.26 (m, 4H),
4.60 (dd, J = 8.6, 6.8 Hz, 1H), 2.43 (s, 3H), 1.96–1.75 (m, 2H),
1.56–1.41 (m, 1H), 0.96 (d, J = 6.6 Hz, 3H), 0.94 (d, J = 6.6 Hz, 3H).
The titled compound was synthesized in the same manner as de-
scribed for 64a using 62g instead of 62a as a white powder. Yield 57%
from 61; 1H NMR (300 MHz, CD3OD) d 7.78 (d, J = 8.1 Hz, 2H), 7.67 (d,
J = 8.1 Hz, 2H), 4.44 (dd, J = 9.9, 6.0 Hz, 1H), 1.98–1.76 (m, 2H), 1.47–
1.31 (m, 1H), 0.97 (d, J = 6.6 Hz, 3H), 0.93 (d, J = 6.6 Hz, 3H).
5.1.20. 1-(4-Methoxy-3-methylphenyl)-3-methylbutan-1-
amine hydrochloride (64h)
The titled compound was synthesized in the same manner as
described for 64a using 62h instead of 62a as a beige powder. Yield
46% from 61; 1H NMR (300 MHz, CD3OD) d 7.27–7.16 (m, 2H), 6.96
(d, J = 8.1 Hz, 1H), 4.20 (dd, J = 10, 5.4 Hz, 1H), 3.84 (s, 3H), 2.21 (s,
3H), 1.96–1.83 (m, 1H), 1.78–1.64 (m, 1H),1.48–1.29 (m, 1H), 0.94
(d, J = 6.6 Hz, 3H), 0.91 (d, J = 6.6 Hz, 3H).
5.1.21. 1-(4-Fluoro-3-methylphenyl)-3-methylbutan-1-amine
hydrochloride (64i)
The titled compound was synthesized in the same manner as
described for 64a using 62i instead of 62a as a white powder. Yield
32% from 61; 1H NMR (300 MHz, CD3OD) d 7.35–7.25 (m, 2H), 7.11
(t, J = 9.0 Hz, 1H), 4.29 (dd, J = 10, 5.9 Hz, 1H), 2.30 (d, J = 2.1 Hz,
3H), 1.97–1.83 (m, 1H), 1.81–1.71 (m, 1H), 1.46–1.29 (m, 1H),
0.95 (d, J = 6.6 Hz, 3H), 0.92 (d, J = 6.6 Hz, 3H).
5.1.14. 3-Methyl-1-(3-methylphenyl)butan-1-amine
hydrochloride (64b)
The titled compound was synthesized in the same manner as
described for 64a using 62b instead of 62a as a white powder. Yield
27% from 61; 1H NMR (300 MHz, CD3OD) d 7.34 (t, J = 7.8 Hz, 1H),
7.28–7.18 (m, 3H), 4.26 (dd, J = 10, 5.7 Hz, 1H), 3.03 (s, 3H), 1.96–
1.86 (m, 1H), 1.81–1.69 (m, 1H), 1.50–1.30 (m, 1H), 0.95 (d,
J = 6.6 Hz, 3H), 0.91 (d, J = 6.6 Hz, 3H).
5.1.22. 1-(3,5-Dimethylphenyl)-3-methylbutan-1-amine
hydrochloride (64j)
The titled compound was synthesized in the same manner as
described for 64a using 62j instead of 62a as a white powder. Yield
41% from 61; 1H NMR (300 MHz, CD3OD) d 7.06 (s, 1H), 7.04 (s, 2H),
4.20 (dd, J = 9.9, 5.9 Hz, 1H), 2.33 (s, 6H), 1.96–1.83 (m, 1H), 1.80–
1.69 (m, 1H), 1.47–1.32 (m, 1H), 0.95 (d, J = 6.6 Hz, 3H), 0.91 (d,
J = 6.6 Hz, 3H).
5.1.15. 1-(2-Methoxyphenyl)-3-methylbutan-1-amine
hydrochloride (64c)
The titled compound was synthesized in the same manner as
described for 64a using 62c instead of 62a as a beige powder. Yield
27% from 61; 1H NMR (300 MHz, CD3OD) d 7.44–7.29 (m, 2H), 7.10
(d, J = 8.1 Hz, 1H), 7.02 (m, 1H), 4.57 (dd, J = 9.8, 5.9 Hz, 1H), 3.91 (s,
3H), 2.05–1.92 (m, 1H), 1.81–1.68 (m, 1H), 1.49–1.32 (m, 1H), 0.95
(d, J = 6.6 Hz, 3H), 0.91 (d, J = 6.6 Hz, 3H).
5.1.23. 1-(2,3-Dihydro-1,4-benzodioxin-6-yl)-3-methylbutan-1-
amine hydrochloride (64k)
The titled compound was synthesized in the same manner as
described for 64a using 62k instead of 62a as a yellow powder.
Yield 18% from 61; 1H NMR (300 MHz, CD3OD) d 6.96–6.87 (m,
3H), 4.26 (s, 4H), 4.18 (dd, J = 9.9, 5.1 Hz, 1H), 1.94–1.81 (m, 1H),
1.76–1.64 (m, 1H), 1.47–1.30 (m, 1H), 0.94 (d, J = 6.8 Hz, 3H),
0.91 (d, J = 6.8 Hz, 3H).
5.1.16. 1-(3-Methoxyphenyl)-3-methylbutan-1-amine
hydrochloride (64d)
The titled compound was synthesized in the same manner as
described for 64a using 62d instead of 62a as a white powder. Yield
21% from 61; 1H NMR (300 MHz, CD3OD) d 7.37 (d, J = 8.3 Hz, 1H),
7.03–6.95 (m, 3H), 4.27 (dd, J = 9.9, 5.7 Hz, 1H), 3.82 (s, 3H), 1.96–
1.83 (m, 1H), 1.81–1.68 (m, 1H), 1.50–1.33 (m, 1H), 0.96 (d,
J = 6.6 Hz, 3H), 0.91 (d, J = 6.6 Hz, 3H).
5.1.24. 1-(3-Fluoro-4-methylphenyl)-3-methylbutan-1-amine
hydrochloride (64l)
The titled compound was synthesized in the same manner as
described for 64a using 62l instead of 62a as a white powder. Yield
39% from 61; 1H NMR (300 MHz, CD3OD) d 7.33 (t, J = 7.7 Hz, 1H),
7.20–7.11 (m, 2H), 4.29 (dd, J = 10, 5.9 Hz, 1H), 2.28 (s, 3H), 1.95–
1.83 (m, 1H), 1.81–1.69 (m, 1H), 1.48–1.31 (m, 1H), 0.96 (d,
J = 6.3 Hz, 3H), 0.92 (d, J = 6.3 Hz, 3H).
5.1.17. 1-(3-Fluorophenyl)-3-methylbutan-1-amine
hydrochloride (64e)
The titled compound was synthesized in the same manner as
described for 64a using 62e instead of 62a as a white powder. Yield
26% from 61; 1H NMR (300 MHz, CD3OD) d 7.53–7.43 (m, 1H),
7.32–7.12 (m, 3H), 4.35 (dd, J = 9.6, 5.7 Hz, 1H), 1.97–1.72 (m,
2H), 1.48–1.32 (m, 1H), 0.96 (d, J = 6.6 Hz, 3H), 0.92 (d, J = 6.6 Hz,
3H).
5.1.25. 1-(3-Fluoro-4-methoxyphenyl)-3-methylbutan-1-amine
hydrochloride (64m)
The titled compound was synthesized in the same manner as
described for 64a using 62m instead of 62a as a brown powder.
Yield 31% from 61; 1H NMR (300 MHz, CD3OD) d 7.28–7.11 (m,
3H), 4.27 (dd, J = 9.9, 5.7 Hz, 1H), 3.89 (s, 3H), 1.96–1.83 (m, 1H),
1.78–1.67 (m, 1H), 1.47–1.30 (m, 1H), 0.94 (d, J = 6.6 Hz, 3H),
0.91 (d, J = 6.6 Hz, 3H).
5.1.18. 3-Methyl-1-[3-(trifluoromethyl)phenyl]butan-1-amine
hydrochloride (64f)
The titled compound was synthesized in the same manner as
described for 64a using 62f instead of 62a as a white powder. Yield
54% from 61; 1H NMR (300 MHz, CD3OD) d 7.83–7.63 (m, 4H), 4.46
(dd, J = 9.7, 6.2 Hz, 1H), 1.98–1.77 (m, 2H), 1.47–1.30 (m, 1H), 0.97
(d, J = 6.6 Hz, 3H), 0.93 (d, J = 6.6 Hz, 3H).
5.1.26. 1-(3,5-Difluorophenyl)-3-methylbutan-1-amine
hydrochloride (64n)
The titled compound was synthesized in the same manner as
described for 64a using 62n instead of 62a as a white powder.

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M. Asada et al. / Bioorg. Med. Chem. 18 (2010) 1641–1658
Yield 10% from 61; 1H NMR (300 MHz, CD3OD) d 7.19–7.01 (m, 3H),
4.38 (dd, J = 9.5, 6.2 Hz, 1H), 1.95–1.72 (m, 2H), 1.50–1.32 (m, 1H),
0.97 (d, J = 6.6 Hz, 3H), 0.94 (d, J = 6.6 Hz, 3H).
5.1.31. 1-(4-Methoxyphenyl)-3-methylbutan-1-amine (75)
To a stirred solution of 71 (380 mg, 1.98 mmol) in MeOH
(10 mL) was added NaBH4 (112 mg, 2.97 mmol) at 0 °C under ar-
gon atmosphere. After being stirred for 2 h, the reaction was
quenched with water and then the reaction mixture was extracted
with EtOAc. The organic layer was washed with brine, dried over
MgSO4, and concentrated in vacuo. The resultant residue was dis-
solved in CH2Cl2 (3 mL) and then TEA (1.29 mL, 9.18 mmol) and
LiCl (485 mg, 11.5 mmol) were added. To the stirred solution was
added MsCl (0.355 mL, 4.59 mmol) at 0 °C under argon atmo-
sphere. After being stirred for 14 h at room temperature, the reac-
tion mixture was diluted with EtOAc and then washed with water
and brine, dried over MgSO4, and concentrated in vacuo. The resul-
tant residue was dissolved in DMF (2 mL) and then NaN3 (179 mg,
2.74 mmol) was added. After being stirred for 3 h at room temper-
ature under argon atmosphere, water was added and then the
resultant mixture was extracted with EtOAc. The organic layer
was washed with brine, dried over MgSO4, and concentrated in va-
cuo. The resultant residue was dissolved in EtOH (3 mL) and then
Pd/C (10%, wet, 45 mg) was added. The resultant suspension was
stirred for 1 h at room temperature under hydrogen atmosphere.
The reaction mixture was filtered through a pad of Celite and the
filtrate was concentrated in vacuo. The resultant residue was puri-
fied by column chromatography on silica gel (CHCl3/MeOH, 99:1–
90:10) to yield 75 (74 mg, 19% in four steps) as a colorless oil. 1H
5.1.27. 1-(3-Chlorophenyl)-3-methylbutan-1-amine
hydrochloride (69a)
To a stirred solution of 65a (500 mg, 2.61 mmol) in THF (10 mL)
was added dropwise n-BuLi (1.59 M in hexane, 1.81 mL,
2.87 mmol) at ꢁ70 °C under argon atmosphere and then the mix-
ture was stirred for 1 h at ꢁ70 °C. To the resultant mixture was
added dropwise isovaleraldehyde (60) (0.225 mL, 3.03 mmol) at
ꢁ70 °C. After being stirred for 2 h at ꢁ70 °C, the reaction was
quenched with water and then the reaction mixture was extracted
with EtOAc. The organic layer was washed with water and brine,
dried over MgSO4, and concentrated in vacuo. The resultant residue
was diluted with CH2Cl2 (7 mL) and then PBr3 (0.272 mL,
2.87 mmol) was added at ꢁ25 °C under argon atmosphere. After
being stirred for 1 h at ꢁ15 °C, the reaction mixture was diluted
with EtOAc, washed with water and brine, dried over MgSO4, and
concentrated in vacuo. The resultant residue was dissolved in
DMF (6 mL) and then NaN3 (190 mg, 2.87 mmol) was added. After
being stirred for 2 h at 50 °C under argon atmosphere, the reaction
mixture was diluted with Et2O, washed with water and brine, dried
over MgSO4, and concentrated in vacuo. The resultant residue was
dissolved in THF (9 mL) and water (1 mL), and then Ph3P (1.37 g,
5.22 mmol) was added under argon atmosphere. After being stir-
red for 24 h, the reaction mixture was diluted with EtOAc, washed
with aqueous NaHCO3, water and brine, dried over MgSO4, and
concentrated in vacuo. The resultant residue was dissolved in
MeOH (1 mL) and then 4 M HCl in dioxane (2 mL) was added. After
concentration in vacuo, the resultant solid was washed with EtOAc
to yield 69a (77 mg, 13% from 65a) as a white powder. 1H NMR
(300 MHz, CD3OD) d 7.53–7.34 (m, 4H), 4.33 (dd, J = 9.6, 6.0 Hz,
1H), 1.96–1.71 (m, 2H), 1.47–1.32 (m, 1H), 0.96 (d, J = 6.6 Hz,
3H), 0.93 (d, J = 6.6 Hz, 3H).
NMR (300 MHz, CDCl3)
d 7.24 (d, J = 8.7 Hz, 2H), 6.87 (d,
J = 8.7 Hz, 2H), 3.92 (t, J = 6.9 Hz, 1H), 3.80 (s, 3H), 2.15 (br s, 2H),
1.78–1.44 (m, 3H), 0.91 (d, J = 6.3 Hz, 3H), 0.89 (d, J = 6.3 Hz, 3H).
5.1.32. 7-(Bromomethyl)-2H-chromen-2-one (77)
A solution of 76 (35.0 g, 0.220 mol), NBS (38.8 g, 0.220 mol), and
AIBN (360 mg, 2.20 mmol) in CCl4 (1000 mL) was refluxed for 1 h.
To the reaction mixture were added NBS (4.00 g, 25.1 mmol)) and
AIBN (50 mg, 0.306 mmol) at room temperature and then the reac-
tion mixture was refluxed for additionally 1 h. After concentration
in vacuo, the resultant residue was diluted with water and then
stirred for 1 h. The resultant precipitate was collected by filtration
and dried under reduced pressure to yield 77, which was used for
the next step without purification. 1H NMR (300 MHz, CDCl3) d
7.70 (d, J = 9.6 Hz, 1H), 7.47 (d, J = 7.8 Hz, 1H), 7.35 (m, 1H), 7.32
(m, 1H), 6.44 (d, J = 9.6 Hz, 1H), 4.52 (s, 2H).
5.1.28. 1-(4-Chlorophenyl)-3-methylbutan-1-amine
hydrochloride (69b)
The titled compound was synthesized in the same manner as de-
scribed for 69a using 65b instead of 65a as a white powder. Yield 75%
from 65b; 1H NMR (300 MHz, CD3OD) d 7.52–7.37 (m, 4H), 4.33 (dd,
J = 9.6, 6.0 Hz, 1H), 1.96–1.83 (m, 1H), 1.81–1.70 (m, 1H), 1.47–1.30
(m, 1H), 0.95 (d, J = 6.8 Hz, 3H), 0.92 (d, J = 6.8 Hz, 3H).
5.1.33. 7-(Phenoxymethyl)-2H-chromen-2-one (78)
To a stirred suspension of NaH (63.1% in oil, 8.30 g, 0.220 mol) in
DMF (200 mL) were successively added dropwise phenol (20.5 g,
0.220 mol) in DMF (100 mL) and 77 in DMF (500 mL) at 0 °C under
argon atmosphere. After being stirred for 12 h at room temperature,
the reaction was quenched with aqueous NH4Cl at 0 °C and then the
reaction mixture was extracted with EtOAc. The organic layer was
washed with brine, dried over MgSO4, and concentrated in vacuo.
The resultant residue was recrystallized with EtOAc–hexane to
yield 78 (45.0 g, 77% in two steps) as a pale yellow powder. 1H
NMR (300 MHz, CDCl3) d 7.70 (d, J = 9.6 Hz, 1H), 7.52–7.25 (m,
5H), 7.04–6.93 (m, 3H), 6.42 (d, J = 9.6 Hz, 1H), 5.16 (s, 2H).
5.1.29. 1-(3-Chloro-4-fluorophenyl)-3-methylbutan-1-amine
hydrochloride (69c)
The titled compound was synthesized in the same manner as
described for 69a using 65c instead of 65a as a white powder. Yield
50% from 65c; 1H NMR (300 MHz, CD3OD) d 7.64 (dd, J = 6.8, 2.3 Hz,
1H), 7.49–7.41 (m, 1H), 7.35 (t, J = 8.7 Hz, 1H), 4.35 (dd, J = 9.8,
6.2 Hz, 1H), 1.97–1.72 (m, 2H), 1.49–1.32 (m, 1H), 0.96 (d,
J = 6.6 Hz, 3H), 0.93 (d, J = 6.6 Hz, 3H).
5.1.30. 1-(4-Methoxyphenyl)-3-methylbutan-1-one (71)
To a stirred solution of 70 (1.00 g, 7.51 mmol) in THF (20 mL)
was added dropwise i-butylmagnesium chloride (1 M in THF,
9.01 mL, 9.01 mmol) at 0 °C under argon atmosphere. After being
stirred for 7 h at room temperature, the reaction was quenched
with 1 M HCl at 0 °C and then the reaction mixture was extracted
with EtOAc. The organic layer was washed with water and brine,
dried over MgSO4, and concentrated in vacuo. The resultant residue
was purified by column chromatography on silica gel (EtOAc/hex-
ane, 1:15) to yield 71 (730 mg, 51%) as a colorless oil. 1H NMR
(300 MHz, CDCl3) d 7.94 (d, J = 8.7 Hz, 2H), 6.93 (d, J = 8.7 Hz, 2H),
3.87 (s, 3H), 2.78 (d, J = 6.9 Hz, 2H), 2.28 (m, 1H), 0.98 (d,
J = 6.6 Hz, 6H).
5.1.34. tert-Butyl (2E)-3-[2-(acetyloxy)-4-(phenoxymethyl)phe-
nyl]acrylate (79)
To a stirred solution of 78 (28.4 g, 0.111 mol) in THF (330 mL)
was added t-BuOK (37.3 g, 0.333 mol) at room temperature under
argon atmosphere. The reaction mixture was stirred for 1 h at 45 °C
and then acetyl chloride (23.6 mL, 0.333 mol) was added dropwise
at 0 °C. After being stirred for 30 min at 0 °C, the reaction was
quenched with water and then the reaction mixture was extracted
with EtOAc. The organic layer was washed with brine, dried over
MgSO4, and concentrated in vacuo to yield 79, which was used
for the next step without purification. 1H NMR (300 MHz, CDCl3)

M. Asada et al. / Bioorg. Med. Chem. 18 (2010) 1641–1658
1651
d 7.64 (d, J = 7.8 Hz, 1H), 7.63 (d, J = 16 Hz, 1H), 7.34–7.15 (m, 4H),
7.02–6.92 (m, 3H), 6.39 (d, J = 16 Hz, 1H), 5.07 (s, 2H), 2.37 (s, 3H),
1.53 (s, 9H).
20 h at 70 °C. After cooling to room temperature, the resultant
mixture was filtrated and the resin was washed with CH2Cl2
(3 mL ꢂ 4). The filtrate and washings were combined and concen-
trated in vacuo. After purificationby a short-passed column chroma-
tography on silica gel (EtOAc), the resultant residue was dissolved in
CH2Cl2 (0.5 mL). To the stirred solution were successively added ani-
sole (0.250 mL) and trifluoroacetic acid (3 mL) at room temperature.
After being stirred for 12 h at room temperature, the reaction mix-
ture was concentrated in vacuo. The resultant residue was recrystal-
lized from EtOAc and hexane to yield 3 (58 mg, 58% in two steps) as a
white powder. 1H NMR (300 MHz, CDCl3) d 7.48–7.38 (m, 2H), 7.38–
7.13 (m, 7H), 7.05–6.91 (m, 3H), 6.32 (d, J = 8.0 Hz, 1H), 5.60–5.41
(m, 1H), 5.03 (s, 2H), 3.10–2.97 (m, 2H), 2.75 (t, J = 7.6 Hz, 2H),
2.49 (s, 3H), 1.88–1.57 (m, 3H), 1.03 (d, J = 6.2 Hz, 3H), 0.98 (d,
J = 6.2 Hz, 3H); MS (APCI, Neg.) m/e 458 (MꢁH)ꢁ; HRMS (Pos.) calcd
for C29H34NO4: 460.2488; found: 460.2497.
5.1.35. tert-Butyl 3-[2-hydroxy-4-(phenoxymethyl)phenyl]pro-
panoate (81)
To a stirred solution of 79 and NiCl2ꢀ6H2O (26.4 g, 0.111 mol) in
THF (250 mL) and MeOH (100 mL) was added NaBH4 (16.8 g,
0.455 mol) in several portions for 30 min at 0 °C under argon atmo-
sphere. After being stirred for 15 min at 0 °C, the reaction mixture
was diluted with EtOAc and water, and then filtered through a pad
of Celite. The filtrate was separated and the organic layer was
washed with water and brine, dried over MgSO4, and concentrated
in vacuo. The resultant residue was dissolved in MeOH (50 mL) and
the solution was added dropwise to a stirred solution of K2CO3
(18.4 g, 0.133 mol) in MeOH (150 mL) at 0 °C under argon atmo-
sphere. After being stirred for 15 min at room temperature, the
reaction mixture was diluted with EtOAc and then filtered through
a pad of Celite. The filtrate was washed with water and brine, dried
over MgSO4, and concentrated in vacuo to yield 81, which was used
for the next step without purification. 1H NMR (300 MHz, CDCl3) d
7.68 (s, 1H), 7.32–7.22 (m, 2H), 7.07 (d, J = 7.8 Hz, 1H), 7.00–6.90
(m, 5H), 4.98 (s, 2H), 2.88–2.81 (m, 2H), 2.66–2.60 (m, 2H), 1.42
(s, 9H).
5.1.39. 3-[2-({[3-Methyl-1-(3-methylphenyl)butyl]amino}car-
bonyl)-4-(phenoxymethyl)phenyl]propanoic acid (4)
The titled compound was synthesized in the same manner as
described for 3 using 64b instead of 64a as a white powder. Yield
56% in two steps; 1H NMR (300 MHz, CDCl3) d 7.46–7.39 (m, 2H),
7.36–7.20 (m, 4H), 7.20–7.05 (m, 3H), 7.03–6.93 (m, 3H), 6.33 (d,
J = 8.5 Hz, 1H), 5.28–5.13 (m, 1H), 5.03 (s, 2H), 3.11–2.96 (m, 2H),
2.73 (t, J = 7.7 Hz, 2H), 2.36 (s, 3H), 1.90–1.49 (m, 3H), 0.99 (d,
J = 6.3 Hz, 6H); MS (APCI, Neg.) m/e 458 (MꢁH)ꢁ; HRMS (Pos.) calcd
for C29H34NO4: 460.2488; found: 460.2498.
5.1.36. 2-(3-tert-Butoxy-3-oxopropyl)-5-(phenoxymethyl)ben-
zoic acid (83)
To a stirred solution of 81 and pyridine (13.5 mL, 0.167 mol) in
CH2Cl2 (150 mL) was added dropwise Tf2O (22.4 mL, 0.133 mol) at
0 °C under argon atmosphere. After being stirred for 10 min at 0 °C,
the reaction was quenched with water and then the reaction mix-
ture was extracted with EtOAc. The organic layer was washed with
water and brine, dried over MgSO4, and concentrated in vacuo to
yield 82, which was used for the next step without purification.
A suspension of 82, potassium acetate (54.5 g, 0.555 mol), DPPF
(6.15 g, 11.1 mmol), and Pd(OAc)2 (1.24 g, 5.55 mmol) was stirred
for 5 h at 75 °C under carbon monooxide atmosphere. The reaction
mixture was diluted with EtOAc and water, and then filtered
through a pad of Celite. The filtrate was separated and the aqueous
layer was extracted with EtOAc. The combined organic layer was
washed with water and brine, dried over MgSO4, and concentrated
in vacuo. The resultant residue was purified by column chromatog-
raphy on silica gel (EtOAc/hexane, 1:2 to 1:1) to yield 83 (17.0 g,
43% from 78) as a yellow oil. 1H NMR (300 MHz, CDCl3) d 8.10 (d,
J = 1.8 Hz, 1H), 7.56 (dd, J = 7.8, 1.8 Hz, 1H), 7.39–7.25 (m, 3H),
7.02–6.94 (m, 3H), 5.08 (s, 2H), 3.29 (t, J = 7.5 Hz, 2H), 2.62 (t,
J = 7.5 Hz, 2H), 1.41 (s, 9H).
5.1.40. 3-[2-({[1-(2-Methoxyphenyl)-3-methylbutyl]amino}car-
bonyl)-4-(phenoxymethyl)phenyl]propanoic acid (6)
The titled compound was synthesized in the same manner as
described for 3 using 64c instead of 64a as a white powder. Yield
68% in two steps; 1H NMR (300 MHz, DMSO-d6) d 12.08 (s, 1H),
8.73 (d, J = 8.8 Hz, 1H), 7.41 (dd, J = 7.8, 1.8 Hz, 1H), 7.37–7.24
(m, 5H), 7.24–7.14 (m, 1H), 7.05–6.82 (m, 5H), 5.51–5.36 (m,
1H), 5.10 (s, 2H), 3.82 (s, 3H), 3.01–2.75 (m, 2H), 2.49–2.39 (m,
2H), 1.82–1.50 (m, 2H), 1.44–1.28 (m, 1H), 0.94 (d, J = 6.6 Hz,
3H), 0.88 (d, J = 6.6 Hz, 3H); MS (FAB, Pos.) m/e 476 (M+H)+; HRMS
(Pos.) calcd for C29H34NO5: 476.2437; found: 476.2438.
5.1.41. 3-[2-({[1-(3-Methoxyphenyl)-3-methylbutyl]amino}car-
bonyl)-4-(phenoxymethyl)phenyl]propanoic acid (7)
The titled compound was synthesized in the same manner as
described for 3 using 64d instead of 64a as a white powder. Yield
68% in two steps; 1H NMR (300 MHz, CDCl3) d 7.49–7.40 (m, 2H),
7.36–7.22 (m, 4H), 7.06–6.88 (m, 5H), 6.86–6.76 (m, 1H), 6.38 (d,
J = 8.5 Hz, 1H), 5.29–5.14 (m, 1H), 5.03 (s, 2H), 3.81 (s, 3H), 3.10–
2.97 (m, 2H), 2.75 (t, J = 7.6 Hz, 2H), 1.86–1.50 (m, 3H), 0.99 (d,
J = 6.3 Hz, 6H); MS (APCI, Neg.) m/e 474 (MꢁH)ꢁ; HRMS (Pos.) calcd
for C29H34NO5: 476.2437; found: 476.2436.
5.1.37. Nitrophenol ester resin (85)
Nitrophenol resin 84 (1.80 mmol/g, 9.10 g, 16.4 mmol) was sus-
pended in dichloroethane (110 mL). To the suspension were suc-
cessively added 83 (7.00 g, 19.7 mmol), DMAP (2.40 g,
19.7 mmol), and EDCꢀHCl (3.77 g, 19.7 mmol) and the suspension
was agitated for 20 h at 60 °C. After cooling to room temperature,
the resin was collected by filtration and washed with CH2Cl2. Dry-
ing under reduced pressure afforded the nitrophenol ester resin 85
(14.5 g, 0.729 mmol/g) as a yellow resin. IR (KBr) 3434, 3026, 2925,
1945, 1751, 1720, 1655, 1609, 1534, 1492, 1450, 1347, 1127, 1075,
5.1.42. 3-[2-({[1-(2-Fluorophenyl)-3-methylbutyl]amino}car-
bonyl)-4-(phenoxymethyl)phenyl]propanoic acid (9)
The titled compound was synthesized in the same manner as
described for 3 using 59b instead of 64a as a white powder. Yield
18% in two steps; 1H NMR (300 MHz, CDCl3) d 7.48–7.41 (m, 2H),
7.38–7.21 (m, 5H), 7.17–6.93 (m, 5H), 6.57 (d, J = 8.7 Hz, 1H),
5.44–5.32 (m, 1H), 5.03 (s, 2H), 3.09–2.96 (m, 2H), 2.78–2.66 (m,
2H), 1.89–1.51 (m, 3H), 0.99 (d, J = 6.6 Hz, 6H); MS (APCI, Neg.)
m/e 462 (MꢁH)ꢁ; HRMS (Pos.) calcd for C28H31FNO4: 464.2237;
found: 464.2242.
1018, 976, 751, 684, 608, 537 cmꢁ1
.
5.1.38. 3-[2-({[3-Methyl-1-(2-methylphenyl)butyl]amino}car-
bonyl)-4-(phenoxymethyl)phenyl]propanoic acid (3)
The nitrophenol ester resin 85 (0.729 mmol/g, 300 mg,
0.219 mmol) was suspended in dichloroethane (5 mL). To the sus-
5.1.43. 3-[2-({[1-(3-Fluorophenyl)-3-methylbutyl]amino}car-
bonyl)-4-(phenoxymethyl)phenyl]propanoic acid (10)
pension were successively added DIPEA (73
64a (53 mg, 0.250 mmol), and the suspension was agitated for
l
L, 0.420 mmol) and
The titled compound was synthesized in the same manner as
described for 3 using 64e instead of 64a as a white powder. Yield

1652
M. Asada et al. / Bioorg. Med. Chem. 18 (2010) 1641–1658
73% in two steps; 1H NMR (300 MHz, CDCl3) d 7.49–7.40 (m, 2H),
7.37–7.27 (m, 4H), 7.15 (d, J = 8.0 Hz, 1H), 7.09–6.86 (m, 5H),
6.46 (d, J = 8.2 Hz, 1H), 5.27–5.17 (m, 1H), 5.04 (s, 2H), 3.02 (t,
J = 6.9 Hz, 2H), 2.82–2.69 (m, 2H), 1.87–1.53 (m, 3H), 0.99 (d,
J = 6.3 Hz, 3H), 0.98 (d, J = 6.3 Hz, 3H); MS (APCI, Neg.) m/e 462
(MꢁH)ꢁ; HRMS (Pos.) calcd for C28H31FNO4: 464.2237; found:
464.2237.
5.1.49. 3-[2-({[1-(4-Fluoro-3-methylphenyl)-3-methylbutyl]-
amino}carbonyl)-4-(phenoxymethyl)phenyl]propanoic acid
(18)
The titled compound was synthesized in the same manner as
described for 3 using 64i instead of 64a as a white powder. Yield
61% in two steps; 1H NMR (300 MHz, CDCl3) d 7.47–7.38 (m, 2H),
7.35–7.27 (m, 3H), 7.22–7.08 (m, 2H), 7.06–6.92 (m, 4H), 6.35 (d,
J = 8.5 Hz, 1H), 5.26–5.10 (m, 1H), 5.03 (s, 2H), 3.10–2.94 (m, 2H),
2.81–2.67 (m, 2H), 2.27 (d, J = 1.9 Hz, 3H), 1.90–1.50 (m, 3H),
0.98 (d, J = 6.6 Hz, 6H); MS (APCI, Neg.) m/e 476 (MꢁH)ꢁ; HRMS
(Pos.) calcd for C29H33FNO4: 478.2394; found: 478.2396.
5.1.44. 3-[2-({[1-(3-Chlorophenyl)-3-methylbutyl]amino}car-
bonyl)-4-(phenoxymethyl)phenyl]propanoic acid (12)
The titled compound was synthesized in the same manner as
described for 3 using 69a instead of 64a as a white powder. Yield
68% in two steps; 1H NMR (300 MHz, CDCl3) d 7.48–7.39 (m, 2H),
7.38–7.19 (m, 7H), 7.05–6.92 (m, 3H), 6.47 (d, J = 8.2 Hz, 1H),
5.26–5.13 (m, 1H), 5.04 (s, 2H), 3.08–2.95 (m, 2H), 2.82–2.69 (m,
2H), 1.89–1.50 (m, 3H), 0.99 (d, J = 6.3 Hz, 3H), 0.98 (d, J = 6.3 Hz,
3H); MS (APCI, Neg.) m/e 478 (MꢁH)ꢁ; HRMS (Pos.) calcd for
C28H31ClNO4: 480.1942; found: 480.1943.
5.1.50. 3-[2-({[1-(3,5-Dimethylphenyl)-3-methylbutyl]amino}-
carbonyl)-4-(phenoxymethyl)phenyl]propanoic acid (19)
The titled compound was synthesized in the same manner as
described for 3 using 64j instead of 64a as a white powder. Yield
71% in two steps; 1H NMR (300 MHz, CDCl3) d 7.45–7.38 (m, 2H),
7.35–7.23 (m, 3H), 7.02–6.87 (m, 6H), 6.30 (d, J = 8.4 Hz, 1H),
5.16 (m, 1H), 5.02 (s, 2H), 3.11–2.94 (m, 2H), 2.71 (t, J = 7.7 Hz,
2H), 2.30 (s, 6H), 1.84–1.52 (m, 3H), 0.98 (d, J = 6.3 Hz, 6H); IR
(KBr) 3295, 1700, 1637, 1602, 1528, 1301, 1240, 1172, 1036, 847,
820, 755, 691 cmꢁ1; MS (APCI, Neg.) m/e 472 (MꢁH)ꢁ; HRMS
(Pos.) calcd for C30H36NO4: 474.2644; found: 474.2642.
5.1.45. 3-[2-({[1-(4-Chlorophenyl)-3-methylbutyl]amino}car-
bonyl)-4-(phenoxymethyl)phenyl]propanoic acid (13)
The titled compound was synthesized in the same manner as
described for 3 using 69b instead of 64a as a white powder. Yield
68% in two steps; 1H NMR (300 MHz, CDCl3) d 7.48–7.38 (m, 2H),
7.37–7.27 (m, 7H), 7.05–6.92 (m, 3H), 6.43 (d, J = 8.2 Hz, 1H),
5.28–5.13 (m, 1H), 5.03 (s, 2H), 3.01 (t, J = 6.7 Hz, 2H), 2.81–2.66
(m, 2H), 1.87–1.49 (m, 3H), 0.98 (d, J = 6.6 Hz, 6H); MS (APCI,
Neg.) m/e 478 (MꢁH)ꢁ; HRMS (Pos.) calcd for C28H31ClNO4:
480.1942; found: 480.1935.
5.1.51. 3-[2-({[1-(2,3-Dihydro-1,4-benzodioxin-6-yl)-3-meth-
ylbutyl]amino}carbonyl)-4-(phenoxymethyl)phenyl]propanoic
acid (21)
The titled compound was synthesized in the same manner as
described for 3 using 64k instead of 64a as a white powder. Yield
26% in two steps; 1H NMR (300 MHz, CDCl3) d 7.48–7.38 (m, 2H),
7.36–7.24 (m, 3H), 7.06–6.92 (m, 3H), 6.91–6.80 (m, 3H), 6.29 (d,
J = 8.5 Hz, 1H), 5.21–5.06 (m, 1H), 5.02 (s, 2H), 4.24 (s, 4H), 3.04
(t, J = 7.1 Hz, 2H), 2.74 (t, J = 7.1 Hz, 2H), 1.86–1.47 (m, 3H), 0.97
(t, J = 6.3 Hz, 6H); MS (APCI, Neg.) m/e 502 (MꢁH)ꢁ; HRMS (Pos.)
calcd for C30H34NO6: 504.2386; found: 504.2390.
5.1.46. 3-[2-[({3-Methyl-1-[3-(trifluoromethyl)phenyl]butyl}-
amino)carbonyl]-4-(phenoxymethyl)phenyl]propanoic acid
(14)
The titled compound was synthesized in the same manner as
described for 3 using 64f instead of 64a as a white powder. Yield
56% in two steps; 1H NMR (300 MHz, CDCl3) d 7.68–7.40 (m, 6H),
7.37–7.27 (m, 3H), 7.06–6.92 (m, 3H), 6.60 (d, J = 8.0 Hz, 1H),
5.36–5.21 (m, 1H), 5.04 (s, 2H), 3.06–2.94 (m, 2H), 2.81–2.67 (m,
2H), 1.93–1.55 (m, 3H), 1.01 (d, J = 6.3 Hz, 3H), 0.99 (d, J = 6.3 Hz,
3H); MS (APCI, Neg.) m/e 512 (MꢁH)ꢁ; HRMS (Pos.) calcd for
C29H31F3NO4: 514.2205; found: 514.2211.
5.1.52. 3-[2-({[1-(3-Fluoro-4-methylphenyl)-3-methylbutyl]-
amino}carbonyl)-4-(phenoxymethyl)phenyl]propanoic acid
(22)
The titled compound was synthesized in the same manner as de-
scribed for 3 using 64l instead of 64a as a white powder. Yield 67%
in two steps; 1H NMR (300 MHz, CDCl3) d 7.48–7.38 (m, 2H), 7.35–
7.25 (m, 3H), 7.16 (t, J = 8.0 Hz, 1H), 7.09–6.92 (m, 5H), 6.39 (d,
J = 8.5 Hz, 1H), 5.27–5.11 (m, 1H), 5.03 (s, 2H), 3.03 (t, J = 6.9 Hz,
2H), 2.74 (t, J = 6.9 Hz, 2H), 2.25 (d, J = 1.7 Hz, 3H), 1.86–1.50 (m,
3H), 0.98 (d, J = 6.3 Hz, 6H); MS (APCI, Neg.) m/e 476 (MꢁH)ꢁ;
HRMS (Pos.) calcd for C29H33FNO4: 478.2394; found: 478.2393.
5.1.47. 3-[2-[({3-Methyl-1-[4-(trifluoromethyl)phenyl]butyl}-
amino)carbonyl]-4-(phenoxymethyl)phenyl]propanoic acid
(15)
The titled compound was synthesized in the same manner as
described for 3 using 64g instead of 64a as an off-white powder.
Yield 30% in two steps; 1H NMR (300 MHz, CDCl3) d 7.61 (d,
J = 8.1 Hz, 2H), 7.51–7.40 (m, 4H), 7.35–7.25 (m, 3H), 7.02–6.93
(m, 3H), 6.54 (d, J = 8.1 Hz, 1H), 5.26 (m, 1H), 5.03 (s, 2H), 3.01 (t,
J = 7.2 Hz, 2H), 2.76–2.68 (m, 2H), 1.84–1.55 (m, 3H), 0.99 (d,
J = 6.3 Hz, 3H), 0.98 (d, J = 6.3 Hz, 3H); IR (KBr) 3294, 2959, 1711,
1638, 1532, 1496, 1327, 1245, 1165, 1122, 1068, 1017, 752,
689 cmꢁ1; MS (APCI, Neg.) m/e 512 (MꢁH)ꢁ; HRMS (Pos.) calcd
for C29H31F3NO4: 514.2205; found: 514.2210.
5.1.53. 3-[2-({[1-(3-Fluoro-4-methoxyphenyl)-3-methylbutyl]-
amino}carbonyl)-4-(phenoxymethyl)phenyl]propanoic acid
(23)
The titled compound was synthesized in the same manner as
described for 3 using 64m instead of 64a as a pale pink powder.
Yield 27% in two steps; 1H NMR (300 MHz, CDCl3) d 7.47–7.38
(m, 2H), 7.36–7.27 (m, 3H), 7.16–7.04 (m, 2H), 7.03–6.89 (m,
4H), 6.40 (d, J = 8.2 Hz, 1H), 5.23–5.10 (m, 1H), 5.03 (s, 2H), 3.88
(s, 3H), 3.02 (t, J = 6.9 Hz, 2H), 2.74 (t, J = 6.9 Hz, 2H), 1.90–1.48
(m, 3H), 0.98 (d, J = 6.3 Hz, 6H); MS (APCI, Neg.) m/e 492 (MꢁH)ꢁ;
HRMS (Pos.) calcd for C29H33FNO5: 494.2343; found: 494.2334.
5.1.48. 3-[2-({[1-(3,4-Dimethylphenyl)-3-methylbutyl]amino}-
carbonyl)-4-(phenoxymethyl)phenyl]propanoic acid (16)
The titled compound was synthesized in the same manner as
described for 3 using 59d instead of 64a as a white powder. Yield
36% in two steps; 1H NMR (300 MHz, CDCl3) d 7.48–7.38 (m, 2H),
7.35–7.27 (m, 3H), 7.17–7.06 (m, 3H), 7.03–6.92 (m, 3H), 6.30 (d,
J = 8.8 Hz, 1H), 5.25–5.13 (m, 1H), 5.02 (s, 2H), 3.11–2.97 (m, 2H),
2.75 (t, J = 7.3 Hz, 2H), 2.26 (s, 3H), 2.25 (s, 3H), 1.88–1.50 (m,
3H), 0.98 (d, J = 6.3 Hz, 6H); MS (APCI, Neg.) m/e 472 (MꢁH)ꢁ;
HRMS (Pos.) calcd for C30H36NO4: 474.2644; found: 474.2647.
5.1.54. 3-[2-({[1-(3,4-Difluorophenyl)-3-methylbutyl]amino}-
carbonyl)-4-(phenoxymethyl)phenyl]propanoic acid (24)
The titled compound was synthesized in the same manner as
described for 3 using 59f instead of 64a as a white powder. Yield
22% in two steps; 1H NMR (300 MHz, CDCl3) d 7.48–7.38 (m, 2H),
7.34–7.24 (m, 3H), 7.22–7.07 (m, 3H), 7.02–6.92 (m, 3H), 6.50

M. Asada et al. / Bioorg. Med. Chem. 18 (2010) 1641–1658
1653
(d, J = 8.1 Hz, 1H), 5.23–5.11 (m, 1H), 5.03 (s, 2H), 2.99 (t, J = 7.5 Hz,
2H), 2.78–2.69 (m, 2H), 1.82–1.55 (m, 3H), 0.98 (d, J = 6.0 Hz, 6H);
MS (APCI, Neg.) m/e 480 (MꢁH)ꢁ; HRMS (Pos.) calcd for
C28H30F2NO4: 482.2143; found: 482.2146.
MgSO4, and concentrated in vacuo to yield 87a, which was used
for the next step without purification. The obtained 87a was dis-
solved in THF (1 mL) and MeOH (1 mL) and then 2 M NaOH
(1 mL) was added. After being stirred for 12 h at room tempera-
ture, the reaction mixture was acidified with 1 M HCl and then
extracted with EtOAc. The organic layer was washed with water
and brine, dried over MgSO4, and concentrated in vacuo. The
resultant residue was triturated with EtOAc–hexane to yield 5
5.1.55. 3-[2-[({1-[3-Fluoro-4-(trifluoromethyl)phenyl]-3-meth-
ylbutyl}amino)carbonyl]-4-(phenoxymethyl)phenyl]propanoic
acid (25)
The titled compound was synthesized in the same manner as
described for 3 using 59g instead of 64a as a white powder. Yield
34% in two steps; 1H NMR (300 MHz, CDCl3) d 7.58 (t, J = 7.5 Hz,
1H), 7.47–7.41 (m, 2H), 7.37–7.16 (m, 5H), 7.03–6.92 (m, 3H),
6.64 (d, J = 7.5 Hz, 1H), 5.28–5.17 (m, 1H), 5.04 (s, 2H), 2.99 (t,
J = 7.4 Hz, 2H), 2.80–2.70 (m, 2H), 1.83–1.52 (m, 3H), 1.00 (d,
J = 6.3 Hz, 3H), 0.99 (d, J = 6.3 Hz, 3H); MS (APCI, Neg.) m/e 530
(MꢁH)ꢁ; HRMS (Pos.) calcd for C29H30F4NO4: 532.2111; found:
532.2114.
(210 mg, 75% in two steps) as a
white powder. 1H NMR
(300 MHz, CDCl3) d 7.46–7.12 (m, 9H), 7.02–6.92 (m, 3H), 6.33
(d, J = 8.4 Hz, 1H), 5.20 (m, 1H), 5.02 (s, 2H), 3.07–2.95 (m,
2H), 2.78–2.69 (m, 2H), 2.34 (s, 3H), 1.88–1.44 (m, 3H), 0.98
(d, J = 6.3 Hz, 6H); IR (KBr) 3293, 2954, 1707, 1637, 1599,
1533, 1496, 1435, 1368, 1302, 1234, 1172, 1140, 1104, 1078,
1032, 1015, 903, 814, 754 cmꢁ1
; MS (APCI, Neg.) m/e 458
(MꢁH)ꢁ; HRMS (Pos.) calcd for C29H34NO4: 460.2488; found:
460.2497.
5.1.56. 3-[2-({[1-(3,5-Difluorophenyl)-3-methylbutyl]amino}-
carbonyl)-4-(phenoxymethyl)phenyl]propanoic acid (26)
The titled compound was synthesized in the same manner as
described for 3 using 64n instead of 64a as a white powder. Yield
46% in two steps; 1H NMR (300 MHz, CDCl3) d 7.48–7.40 (m, 2H),
7.35–7.24 (m, 3H), 7.02–6.94 (m, 3H), 6.94–6.84 (m, 2H), 6.76–
6.66 (m, 1H), 6.54 (d, J = 8.4 Hz, 1H), 5.23–5.13 (m, 1H), 5.04 (s,
2H), 3.02 (t, J = 7.2 Hz, 2H), 2.80–2.70 (m, 2H), 1.80–1.40 (m, 3H),
0.99 (d, J = 6.0 Hz, 3H), 0.98 (d, J = 6.0 Hz, 3H); IR (KBr) 3286,
2958, 1708, 1639, 1599, 1531, 1496, 1454, 1317, 1246, 1171,
1119, 1054, 991, 911, 851, 751, 689 cmꢁ1; MS (APCI, Neg.) m/e
480 (MꢁH)ꢁ; HRMS (Pos.) calcd for C28H30F2NO4: 482.2143; found:
482.2143.
5.1.60. 3-[2-({[1-(4-Methoxyphenyl)-3-methylbutyl]amino}-
carbonyl)-4-(phenoxymethyl)phenyl]propanoic acid (8)
The titled compound was synthesized in the same manner as
described for 5 using 75 instead of 59a as a white powder. Yield
63% in two steps; 1H NMR (300 MHz, CDCl3) d 7.45–7.38 (m, 2H),
7.34–7.23 (m, 5H), 7.03–6.93 (m, 3H), 6.88 (d, J = 8.7 Hz, 2H),
6.33 (d, J = 8.1 Hz, 1H), 5.19 (m, 1H), 5.02 (s, 2H), 3.80 (s, 3H),
3.01 (dt, J = 3.0, 7.2 Hz, 2H), 2.72 (t, J = 7.2 Hz, 2H), 1.85–1.65 (m,
2H), 1.63 (m, 1H), 0.97 (d, J = 6.6 Hz, 6H); IR (KBr) 3303, 2958,
1701, 1632, 1516, 1308, 1252, 1213, 1032, 831, 752, 691 cmꢁ1
;
MS (APCI, Neg.) m/e 474 (MꢁH)ꢁ; HRMS (Pos.) calcd for
C29H34NO5: 476.2437; found: 476.2437.
5.1.61. 3-[2-({[1-(4-Fluorophenyl)-3-methylbutyl]amino}-
carbonyl)-4-(phenoxymethyl)phenyl]propanoic acid (11)
The titled compound was synthesized in the same manner as
described for 5 using 59c instead of 59a as a white powder. Yield
76% in two steps; 1H NMR (300 MHz, CDCl3) d 7.46–7.24 (m, 7H),
7.08–6.93 (m, 5H), 6.40 (d, J = 8.4 Hz, 1H), 5.21 (m, 1H), 5.02 (s,
2H), 3.05–2.95 (m, 2H), 2.76–2.67 (m, 2H), 1.86–1.51 (m, 3H),
0.98 (d, J = 6.6 Hz, 6H); IR (KBr) 3292, 2956, 1709, 1638, 1600,
1510, 1467, 1368, 1302, 1231, 1160, 1096, 1079, 1033, 1015,
904, 836, 817 cmꢁ1; MS (APCI, Neg.) m/e 462 (MꢁH)ꢁ; HRMS
(Pos.) calcd for C28H31FNO4: 464.2237; found: 464.2239.
5.1.57. 3-[2-[({1-[3-Fluoro-5-(trifluoromethyl)phenyl]-3-meth-
ylbutyl}amino)carbonyl]-4-(phenoxymethyl)phenyl]propanoic
acid (27)
The titled compound was synthesized in the same manner as
described for 3 using 59h instead of 64a as a white powder. Yield
29% in two steps; 1H NMR (300 MHz, CDCl3) d 7.50–7.39 (m, 3H),
7.37–7.17 (m, 5H), 7.05–6.92 (m, 3H), 6.68 (d, J = 8.0 Hz, 1H),
5.31–5.18 (m, 1H), 5.04 (s, 2H), 3.06–2.94 (m, 2H), 2.82–2.67 (m,
2H), 1.88–1.54 (m, 3H), 1.01 (d, J = 5.8 Hz, 3H), 0.99 (d, J = 5.8 Hz,
3H); MS (APCI, Neg.) m/e 530 (MꢁH)ꢁ; HRMS (Pos.) calcd for
C29H30F4NO4: 532.2111; found: 532.2120.
5.1.62. 3-[2-({[1-(4-Methoxy-3-methylphenyl)-3-methylbutyl]-
amino}carbonyl)-4-(phenoxymethyl)phenyl]propanoic acid
(17)
5.1.58. 3-[2-({[1-(3-Chloro-4-fluorophenyl)-3-methylbutyl]-
amino}carbonyl)-4-(phenoxymethyl)phenyl]propanoic acid
(28)
The titled compound was synthesized in the same manner as
described for 5 using 64h instead of 59a as a white powder. Yield
57% in two steps; 1H NMR (300 MHz, CDCl3) d 7.48–7.36 (m, 2H),
7.36–7.26 (m, 3H), 7.20–7.09 (m, 2H), 7.04–6.91 (m, 3H), 6.79 (d,
J = 8.2 Hz, 1H), 6.27 (d, J = 8.8 Hz, 1H), 5.26–5.09 (m, 1H), 5.02 (s,
2H), 3.82 (s, 3H), 3.10–2.96 (m, 2H), 2.73 (t, J = 7.4 Hz, 2H), 2.22
(s, 3H), 1.92–1.46 (m, 3H), 0.98 (d, J = 6.6 Hz, 6H); MS (APCI,
Neg.) m/e 488 (MꢁH)ꢁ; HRMS (Pos.) calcd for C30H36NO5:
490.2593; found: 490.2590.
The titled compound was synthesized in the same manner as
described for 3 using 69c instead of 64a as a white powder. Yield
54% in two steps; 1H NMR (300 MHz, CDCl3) d 7.49–7.37 (m, 3H),
7.36–7.20 (m, 4H), 7.11 (t, J = 8.7 Hz, 1H), 7.03–6.93 (m, 3H), 6.50
(d, J = 8.0 Hz, 1H), 5.23–5.11 (m, 1H), 5.04 (s, 2H), 3.01 (t,
J = 6.9 Hz, 2H), 2.81–2.69 (m, 2H), 1.90–1.48 (m, 3H), 0.99 (d,
J = 6.3 Hz, 3H), 0.98 (d, J = 6.3 Hz, 3H); MS (APCI, Neg.) m/e 496
(MꢁH)ꢁ; HRMS (Pos.) calcd for C28H30ClFNO4: 498.1847; found:
498.1848.
5.1.63. 3-[2-({[1-(3,4-Dimethoxyphenyl)-3-methylbutyl]amino}-
carbonyl)-4-(phenoxymethyl)phenyl]propanoic acid (20)
The titled compound was synthesized in the same manner as
described for 5 using 59e instead of 59a as a white powder. Yield
76% in two steps; 1H NMR (300 MHz, CDCl3) d 7.47–7.38 (m, 2H),
7.37–7.25 (m, 3H), 7.07–6.78 (m, 6H), 6.32 (d, J = 8.5 Hz, 1H),
5.29–5.13 (m, 1H), 5.02 (s, 2H), 3.89 (s, 3H), 3.87 (s, 3H), 3.11–
2.96 (m, 2H), 2.74 (t, J = 7.3 Hz, 2H), 1.90–1.47 (m, 3H), 0.99 (d,
J = 6.3 Hz, 6H); MS (APCI, Neg.) m/e 504 (MꢁH)ꢁ; HRMS (Pos.) calcd
for C30H36NO6: 506.2543; found: 506.2544.
5.1.59. 3-[2-({[3-Methyl-1-(4-methylphenyl)butyl]amino}-
carbonyl)-4-(phenoxymethyl)phenyl]propanoic acid (5)
A
solution of 86 (200 mg, 0.612 mmol), 59a (144 mg,
0.673 mmol), N-methylmorpholine (67
l
L, 0.612 mmol), EDCꢀHCl
(141 mg, 0.735 mmol), and HOBt (165 mg, 1.22 mmol) in DMF
(2 mL) was stirred for 12 h at room temperature under argon
atmosphere. The reaction was quenched with 1 M HCl and then
the reaction mixture was extracted with TBME. The organic layer
was washed with aqueous NaHCO3, water and brine, dried over

1654
M. Asada et al. / Bioorg. Med. Chem. 18 (2010) 1641–1658
5.1.64. 7-[(Methoxymethoxy)methyl]-2H-chromen-2-one (90)
Compound 77 was prepared from 76 (64.5 g, 0.403 mol)
according to the aforementioned procedure and used without
purification. To a stirred solution of 77 in DMF (800 mL) was
added potassium acetate (40.0 g, 0.410 mol) at room tempera-
ture under argon atmosphere. After being stirred for 1 h at
50 °C, the reaction mixture was poured into cold water and then
extracted with EtOAc The organic layer was washed with water
and brine, dried over MgSO4, and concentrated in vacuo. The
resultant residue was dissolved in THF (500 mL) and MeOH
(500 mL) and then 5 M NaOH (200 mL) was added. After being
stirred for 1 h at room temperature, the reaction mixture was
neutralized with 5 M HCl, evaporated to approximately one-third
volume, and extracted with EtOAc. The organic layer was
washed with brine, dried over MgSO4, and concentrated in va-
cuo. The resultant residue was dissolved in dichloroethane
(250 mL) and DIPEA (85.0 mL, 0.490 mol) was added. To the stir-
red solution was added dropwise methoxymethyl chloride
(34.0 mL, 0.450 mol) at 0 °C under argon atmosphere. After being
stirred for 4.5 h at 50 °C, the reaction mixture was poured into
cold water and then extracted with CH2Cl2. The organic layer
was washed with brine, dried over MgSO4, and concentrated in
vacuo. The resultant residue was purified by column chromatog-
raphy on silica gel (EtOAc/hexane, 1:4–1:2) to yield 90 (67.4 g,
76% in four steps) as a white powder. 1H NMR (300 MHz, CDCl3)
d 7.70 (d, J = 9.6 Hz, 1H), 7.46 (d, J = 8.1 Hz, 1H), 7.35 (s, 1H),
7.29–7.24 (m, 1H), 6.41 (d, J = 9.6 Hz, 1H), 4.74 (s, 2H), 4.68 (s,
2H), 3.43 (s, 3H).
5.1.67. 5-[(Methoxymethoxy)methyl]-2-(3-methoxy-3-oxopro-
pyl)benzoic acid (94)
The titled compound was synthesized in the same manner as
described for 83 using 92 instead of 81 as a white powder. Yield
82% in two steps; 1H NMR (300 MHz, CDCl3) d 8.04 (d, J = 1.5 Hz,
1H), 7.49 (dd, J = 8.1, 1.5 Hz, 1H), 7.32 (d, J = 8.1 Hz, 1H), 4.72 (s,
2H), 4.61 (s, 2H), 3.67 (s, 3H), 3.43 (s, 3H), 3.33 (t, J = 7.8 Hz, 2H),
2.70 (t, J = 7.8 Hz, 2H).
5.1.68. Methyl 3-{2-({[1-(3,5-dimethylphenyl)-3-methylbutyl]-
amino}carbonyl)-4-[(methoxymethoxy)methyl]phenyl}
propanoate (95)
A solution of 94 (6.00 g, 21.3 mmol), 64g (6.34 g, 27.8 mmol), N-
methylmorpholine (3.34 mL, 30.8 mmol), EDCꢀHCl (5.82 g,
30.4 mmol), and HOBt (4.65 g, 30.4 mmol) in DMF (50 mL) was
stirred for 12 h at room temperature under argon atmosphere.
The reaction was quenched with water and then the reaction mix-
ture was extracted with TBME. The organic layer was washed with
0.5 M HCl, aqueous NaHCO3, water and brine, dried over MgSO4,
and concentrated in vacuo to yield 95, which was used for the next
step without purification. 1H NMR (300 MHz, CDCl3) d 7.32–7.19
(m, 3H), 6.96 (s, 2H), 6.90 (s, 1H), 6.54 (d, J = 8.7 Hz, 1H), 5.16 (m,
1H), 4.70 (s, 2H), 4.54 (s, 2H), 3.62 (s, 3H), 3.40 (s, 3H), 3.02–2.97
(m, 2H), 2.68–2.62 (m, 2H), 2.31 (s, 6H), 1.83–1.55 (m, 3H), 0.99
(d, J = 6.3 Hz, 3H), 0.98 (d, J = 6.3 Hz, 3H).
5.1.69. Methyl 3-{2-({[1-(3,5-dimethylphenyl)-3-methylbutyl]-
amino}carbonyl)-4-(hydroxymethyl)phenyl} propanoate (96)
To a stirred solution of 95 in MeOH (60 mL) was added 4 M HCl
in dioxane (30 mL) at room temperature and the reaction mixture
was stirred for 2 h at room temperature. After concentration in va-
cuo, the resultant residue was purified by column chromatography
on silica gel (EtOAc/hexane, 1:1) to yield 96 (7.66 g, 87% in two
steps) as a beige powder. 1H NMR (300 MHz, CDCl3) d 7.32–7.29
(m, 2H), 7.20 (d, J = 7.8 Hz, 1H), 6.97 (s, 2H), 6.90 (s, 1H), 6.56 (d,
J = 8.7 Hz, 1H), 5.17 (m, 1H), 4.64 (s, 2H), 3.62 (s, 3H), 3.02–2.97
(m, 2H), 2.69–2.63 (m, 2H), 2.31 (s, 6H), 1.85–1.55 (m, 3H), 0.99
(d, J = 6.3 Hz, 3H), 0.98 (d, J = 6.3 Hz, 3H).
5.1.65. Methyl (2E)-3-{2-hydroxy-4-[(methoxymethoxy)meth-
yl]phenyl}acrylate (91)
To a stirred suspension of NaH (60% in oil, 34.5 g, 0.900 mol) in
THF (800 mL) was added dropwise MeOH (50.0 mL, 1.22 mol) at
room temperature under argon atmosphere and then the reaction
mixture was stirred for 1 h at 50 °C. To the resultant suspension
was added dropwise 90 (67.0 g, 0.300 mol) in THF (400 mL) at
room temperature. After being stirred for 1 h at 60 °C, the reaction
was quenched with aqueous NH4Cl and successively 2 M HCl at
0 °C and then the reaction mixture was extracted with EtOAc.
The organic layer was washed with brine, dried over MgSO4, and
concentrated in vacuo to yield 91 which was used for the next step
without purification. 1H NMR (300 MHz, CDCl3) d 7.95 (d, J = 16 Hz,
1H), 7.45 (d, J = 8.1 Hz, 1H), 6.92 (m, 1H), 6.84 (s, 1H), 6.57 (d,
J = 16 Hz, 1H), 5.64 (s, 1H), 4.71 (s, 2H), 4.56 (s, 2H), 3.81 (s, 3H),
3.42 (s, 3H).
5.1.70. 3-{2-({[1-(3,5-Dimethylphenyl)-3-methylbutyl]amino}-
carbonyl)-4-[(2-fluorophenoxy)methyl]phenyl}propanoic acid
(29)
To a stirred solution of 96 (300 mg, 0.729 mmol) and TEA
(153 lL, 1.09 mmol) in THF (3 mL) was added MsCl (68 lL,
0.875 mmol) at 0 °C under argon atmosphere. After being stirred
for 30 min at 0 °C, the reaction mixture was diluted with EtOAc,
washed with water and brine, dried over MgSO4, and concentrated
in vacuo to yield 97, which was used for the next step without
purification. To a stirred solution of 98a (98 mg, 0.875 mmol) in
DMF (1 mL) was added NaH (60% in oil, 29 mg, 0.801 mmol) at
0 °C under argon atmosphere and the reaction mixture was stirred
for 30 min at room temperature. To the reaction mixture was
added 97 in DMF (1 mL) at 0 °C. After being stirred for 12 h at room
temperature, the reaction was quenched with aqueous NH4Cl and
then the reaction mixture was extracted with TBME. The organic
layer was washed with 0.5 M NaOH, water and brine, and dried
over MgSO4. Concentration in vacuo afforded 99a which was used
for the next step without purification. To a stirred solution of 99a
in THF (2 mL) and MeOH (2 mL) was added 2 M NaOH (2 mL) at
room temperature. After being stirred for 12 h at room tempera-
ture, the reaction mixture was diluted with water and then ex-
tracted with TBME. The aqueous layer was acidified with 1 M HCl
and then extracted with EtOAc. The organic layer was washed with
water and brine, dried over MgSO4, and concentrated in vacuo. The
resultant residue was recrystallized with EtOAc–hexane to yield 29
(193 mg, 54% in three steps) as a white powder. 1H NMR (300 MHz,
5.1.66. Methyl 3-{2-hydroxy-4-[(methoxymethoxy)methyl]-
phenyl}propanoate (92)
To a stirred solution of 91 and NiCl2ꢀ6H2O (53.5 g, 0.225 mol)
in THF (560 mL) and MeOH (140 mL) was added NaBH4 (34.0 g,
0.900 mol) in several portions at 0 °C under argon atmosphere
and then the reaction mixture was stirred for 1 h at room temper-
ature. To the reaction mixture were added NiCl2ꢀ6H2O (26.8 g,
0.113 mol) and successively NaBH4 (17.0 g, 0.450 mol) at room
temperature and the reaction mixture was stirred for additionally
30 min at room temperature. The resultant mixture was diluted
with TBME and then filtered through a pad of Celite. The filtrate
was evaporated to approximately half volume and then poured
into EtOAc and water. The mixture was extracted with EtOAc
and the organic layer was washed with brine, dried over MgSO4,
and concentrated in vacuo. The resultant residue was purified
by column chromatography on silica gel (EtOAc/hexane, 1:3–
1:2) to yield 92 (52.5 g, 80%) as
a
colorless oil. 1H NMR
(300 MHz, CDCl3) d 7.11–7.03 (m, 2H), 6.91–6.83 (m, 2H), 4.69
(s, 2H), 4.51 (s, 2H), 3.68 (s, 3H), 3.41 (s, 3H), 2.93–2.86 (m,
2H), 2.74–2.67 (m, 2H).

M. Asada et al. / Bioorg. Med. Chem. 18 (2010) 1641–1658
1655
CDCl3) d 7.46–7.38 (m, 2H), 7.28 (d, J = 7.8 Hz, 1H), 7.14–6.88 (m,
5.1.76. 3-[4-[(2-Cyanophenoxy)methyl]-2-({[1-(3,5-dimeth-
7H), 6.31 (d, J = 7.8 Hz, 1H), 5.15 (m, 1H), 5.09 (s, 2H), 3.12–2.95
(m, 2H), 2.72 (t, J = 7.2 Hz, 2H), 2.31 (s, 6H), 1.85–1.55 (m, 3H),
0.98 (d, J = 5.7 Hz, 6H); MS (APCI, Neg.) m/e 490 (MꢁH)ꢁ; HRMS
(Pos.) calcd for C30H35FNO4: 492.2550; found: 492.2546.
ylphenyl)-3-methylbutyl]amino}carbonyl)phenyl]propanoic
acid (35)
The titled compound was synthesized in the same manner as
described for 29 using 98g instead of 98a as a white powder. Yield
65% in three steps; 1H NMR (300 MHz, CDCl3) d 7.62–7.49 (m, 2H),
7.43–7.27 (m, 3H), 7.09–6.87 (m, 5H), 6.55 (d, J = 8.7 Hz, 1H), 5.23–
5.07 (m, 3H), 3.03 (t, J = 7.0 Hz, 2H), 2.73 (t, J = 7.0 Hz, 2H), 2.30 (s,
6H), 1.88–1.52 (m, 3H), 0.98 (d, J = 6.0 Hz, 6H); MS (APCI, Neg.) m/e
497 (MꢁH)ꢁ; HRMS (Pos.) calcd for C31H35N2O4: 499.2597; found:
499.2588.
5.1.71. 3-{2-({[1-(3,5-Dimethylphenyl)-3-methylbutyl]amino}-
carbonyl)-4-[(3-fluorophenoxy)methyl]phenyl}propanoic acid
(30)
The titled compound was synthesized in the same manner as
described for 29 using 98b instead of 98a as a white powder. Yield
80% in three steps; 1H NMR (300 MHz, CDCl3) d 7.45–7.35 (m, 2H),
7.30–7.21 (m, 2H), 6.95 (s, 2H), 6.91 (s, 1H), 6.75–6.64 (m, 3H), 6.31
(d, J = 8.2 Hz, 1 H), 5.16 (m, 1H), 5.00 (s, 2H), 3.11–2.95 (m, 2H),
2.80–2.65 (m, 2H), 2.31 (s, 6H), 1.85–1.55 (m, 3H), 0.98 (d,
J = 6.3 Hz, 6H); MS (APCI, Neg.) m/e 490 (MꢁH)ꢁ; HRMS (Pos.) calcd
for C30H35FNO4: 492.2550; found: 492.2548.
5.1.77. 3-[4-[(3-Cyanophenoxy)methyl]-2-({[1-(3,5-dimeth-
ylphenyl)-3-methylbutyl]amino}carbonyl)phenyl]propanoic
acid (36)
The titled compound was synthesized in the same manner as
described for 29 using 98h instead of 98a as a white powder. Yield
67% in three steps; 1H NMR (300 MHz, CDCl3) d 7.48–7.06 (m, 7H),
6.95 (s, 2H), 6.90 (s, 1H), 6.42 (d, J = 7.5 Hz, 1H), 5.16 (m, 1H), 5.00
(s, 2H), 3.10–2.92 (m, 2H), 2.78–2.62 (m, 2H), 2.29 (s, 6H), 1.86–
1.48 (m, 3H), 0.97 (d, J = 6.3 Hz, 6H); IR (KBr) 3282, 2230, 1711,
5.1.72. 3-{2-({[1-(3,5-Dimethylphenyl)-3-methylbutyl]amino}-
carbonyl)-4-[(4-fluorophenoxy)methyl]phenyl}propanoic acid
(31)
1637, 1606, 1532, 1291, 1262, 1168, 1042, 848, 788, 681 cmꢁ1
;
The titled compound was synthesized in the same manner as
described for 29 using 98c instead of 98a as a white powder. Yield
74% in three steps; 1H NMR (300 MHz, CDCl3) d 7.42–7.37 (m, 2H),
7.30–7.26 (m, 1H), 7.02–6.85 (m, 7H), 6.30 (d, J = 8.1 Hz, 1H), 5.20–
5.11 (m, 1H), 4.98 (s, 2H), 3.10–2.95 (m, 2H), 2.73 (t, J = 6.9 Hz, 2H),
2.30 (s, 6H), 1.85–1.50 (m, 3H), 0.98 (d, J = 6.3 Hz, 6H); MS (APCI,
Neg.) m/e 490 (MꢁH)ꢁ; HRMS (Pos.) calcd for C30H35FNO4:
492.2550; found: 492.2552.
MS (APCI, Neg.) m/e 497 (MꢁH)ꢁ; HRMS (Pos.) calcd for
C31H35N2O4: 499.2597; found: 499.2599.
5.1.78. 3-[4-[(4-Cyanophenoxy)methyl]-2-({[1-(3,5-dimeth-
ylphenyl)-3-methylbutyl]amino}carbonyl)phenyl]propanoic
acid (37)
The titled compound was synthesized in the same manner as
described for 29 using 98i instead of 98a as a white powder.
Yield 76% in three steps; 1H NMR (300 MHz, CDCl3) d 7.58 (d,
J = 9.0 Hz, 2H), 7.43–7.26 (m, 3H), 6.99 (d, J = 9.0 Hz, 2H), 6.95
(s, 2H), 6.90 (s, 1H), 6.38 (d, J = 8.4 Hz, 1H), 5.23–5.11 (m, 1H),
5.05 (s, 2H), 3.10–2.96 (m, 2H), 2.82–2.63 (m, 2H), 2.30 (s,
6H), 1.84–1.52 (m, 3H), 0.98 (d, J = 6.3 Hz, 6H); MS (APCI, Neg.)
m/e 497 (MꢁH)ꢁ; HRMS (Pos.) calcd for C31H35N2O4: 499.2597;
found: 499.2600.
5.1.73. 3-[4-[(2-Chlorophenoxy)methyl]-2-({[1-(3,5-dimeth-
ylphenyl)-3-methylbutyl]amino}carbonyl)phenyl]propanoic
acid (32)
The titled compound was synthesized in the same manner as
described for 29 using 98d instead of 98a as a white powder. Yield
57% in three steps; 1H NMR (300 MHz, CDCl3) d 7.51 (s, 1H), 7.46–
7.37 (m, 2H), 7.31–7.17 (m, 2H), 7.00–6.87 (m, 5H), 6.30 (d,
J = 8.4 Hz, 1H), 5.22–5.12 (m, 1H), 5.11 (s, 2H), 3.13–2.96 (m, 2H),
2.73 (t, J = 7.7 Hz, 2H), 2.31 (s, 6H), 1.86–1.54 (m, 3H), 0.98 (d,
J = 6.3 Hz, 3H), 0.96 (d, J = 6.3 Hz, 3H); MS (APCI, Neg.) m/e 506
(MꢁH)ꢁ; HRMS (Pos.) calcd for C30H35ClNO4: 508.2255; found:
508.2255.
5.1.79. 3-{2-({[1-(3,5-Dimethylphenyl)-3-methylbutyl]amino}-
carbonyl)-4-[(2-methylphenoxy)methyl]phenyl}propanoic acid
(38)
The titled compound was synthesized in the same manner as
described for 29 using 98j instead of 98a as a white powder.
Yield 33% in three steps; 1H NMR (300 MHz, CDCl3) d 7.46–
7.39 (m, 2H), 7.31–7.22 (m, 1H), 7.20–7.11 (m, 2H), 6.95 (s,
2H), 6.93–6.82 (m, 3H), 6.26 (d, J = 8.4 Hz, 1H), 5.22–5.12 (m,
1H), 5.04 (s, 2H), 3.14–2.99 (m, 2H), 2.78–2.67 (m, 2H), 2.31
(s, 6H), 2.27 (s, 3H), 1.85–1.52 (m, 3H), 0.99 (d, J = 6.6 Hz, 3H),
0.98 (d, J = 6.6 Hz, 3H); IR (KBr) 3305, 1719, 1637, 1603, 1527,
1246, 1122, 1061, 848, 818 cmꢁ1; MS (APCI, Neg.) m/e 486
(MꢁH)ꢁ; HRMS (Pos.) calcd for C31H38NO4: 488.2801; found:
488.2798.
5.1.74. 3-[4-[(3-Chlorophenoxy)methyl]-2-({[1-(3,5-dimeth-
ylphenyl)-3-methylbutyl]amino}carbonyl)phenyl]propanoic
acid (33)
The titled compound was synthesized in the same manner as
described for 29 using 98e instead of 98a as a white powder. Yield
44% in three steps; 1H NMR (300 MHz, CDCl3) d 7.44–7.37 (m, 2H),
7.32–7.17 (m, 2H), 7.00–6.81 (m, 6H), 6.29 (d, J = 8.7 Hz, 1H), 5.17
(m, 1H), 5.00 (s, 2H), 3.09–2.97 (m, 2H), 2.73 (t, J = 7.1 Hz, 2H), 2.31
(s, 6H), 1.87–1.52 (m, 3H), 0.99 (d, J = 6.3 Hz, 6H); MS (APCI, Neg.)
m/e 506 (MꢁH)ꢁ; HRMS (Pos.) calcd for C30H35ClNO4: 508.2255;
found: 508.2254.
5.1.80. 3-{2-({[1-(3,5-Dimethylphenyl)-3-methylbutyl]amino}-
carbonyl)-4-[(3-methylphenoxy)methyl]phenyl}propanoic acid
(39)
5.1.75. 3-[4-[(4-Chlorophenoxy)methyl]-2-({[1-(3,5-dimeth-
ylphenyl)-3-methylbutyl]amino}carbonyl)phenyl]propanoic
acid (34)
The titled compound was synthesized in the same manner as
described for 29 using 98k instead of 98a as a white powder. Yield
47% in three steps; 1H NMR (300 MHz, CDCl3) d 7.46–7.36 (m, 2H),
7.26 (d, J = 8.4 Hz, 1H), 7.18 (t, J = 8.1 Hz, 1H), 6.95 (s, 2H), 6.90 (s,
1H), 6.85–6.72 (m, 3H), 6.29 (d, J = 9.0 Hz, 1H), 5.24–5.11 (m, 1H),
4.99 (s, 2H), 3.11–2.93 (m, 2H), 2.71 (t, J = 7.5 Hz, 2H), 2.33 (s, 3H),
2.30 (s, 6H), 1.85–1.52 (m, 3H), 0.98 (d, J = 6.3 Hz, 6H); MS (APCI,
Neg.) m/e 486 (MꢁH)ꢁ; HRMS (Pos.) calcd for C31H38NO4:
488.2801; found: 488.2803.
The titled compound was synthesized in the same manner as
described for 29 using 98f instead of 98a as a white powder. Yield
23% in three steps; 1H NMR (300 MHz, CDCl3) d 7.45–7.35 (m, 2H),
7.34–7.19 (m, 3H), 6.95 (s, 2H), 6.93–6.81 (m, 3H), 6.29 (d,
J = 8.5 Hz, 1H), 5.26–5.09 (m, 1H), 4.99 (s, 2H), 3.12–2.95 (m, 2H),
2.74 (t, J = 7.4 Hz, 2H), 2.31 (s, 6H), 1.92–1.47 (m, 3H), 0.98 (d,
J = 6.3 Hz, 6H); MS (APCI, Neg.) m/e 506 (MꢁH)ꢁ; HRMS (Pos.) calcd
for C30H35ClNO4: 508.2255; found: 508.2253.

1656
M. Asada et al. / Bioorg. Med. Chem. 18 (2010) 1641–1658
5.1.81. 3-{2-({[1-(3,5-Dimethylphenyl)-3-methylbutyl]amino}-
carbonyl)-4-[(4-methylphenoxy)methyl]phenyl}propanoic acid
(40)
5.1.86. 3-[4-[(2,6-Difluorophenoxy)methyl]-2-({[1-(3,5-dimeth-
ylphenyl)-3-methylbutyl]amino}carbonyl)phenyl]propanoic
acid (50)
The titled compound was synthesized in the same manner as
described for 29 using 98l instead of 98a as a white powder. Yield
56% in three steps; 1H NMR (300 MHz, CDCl3) d 7.44–7.38 (m, 2H),
7.27 (d, J = 8.1 Hz, 1H), 7.08 (d, J = 8.7 Hz, 2H), 6.94 (s, 2H), 6.90 (s,
1H), 6.85 (d, J = 8.7 Hz, 2H), 6.29 (d, J = 8.4 Hz, 1H), 5.22–5.10 (m,
1H), 4.99 (s, 2H), 3.11–2.93 (m, 2H), 2.72 (t, J = 7.7 Hz, 2H), 2.31
(s, 6H), 2.29 (s, 3H), 1.86–1.52 (m, 3H), 0.98 (d, J = 6.0 Hz, 6H);
MS (APCI, Neg.) m/e 486 (MꢁH)ꢁ; HRMS (Pos.) calcd for
C31H38NO4: 488.2801; found: 488.2800.
The titled compound was synthesized in the same manner as
described for 29 using 98q instead of 98a as a white powder. Yield
16% in three steps; 1H NMR (300 MHz, CDCl3) d 7.49 (s, 1H), 7.42 (d,
J = 8.0 Hz, 1H), 7.32–7.21 (m, 2H), 7.07–6.82 (m, 5H), 6.25 (d,
J = 8.8 Hz, 1H), 5.26–5.08 (m, 3H), 3.13–2.97 (m, 2H), 2.72 (t,
J = 7.3 Hz, 2H), 2.32 (s, 6H), 1.94–1.50 (m, 3H), 1.00 (d, J = 6.0 Hz,
6H); MS (APCI, Neg.) m/e 508 (MꢁH)ꢁ; HRMS (Pos.) calcd for
C30H34F2NO4: 510.2456; found: 510.2460.
5.1.87. 3-[4-[(3,4-Difluorophenoxy)methyl]-2-({[1-(3,5-dimeth-
ylphenyl)-3-methylbutyl]amino}carbonyl)phenyl]propanoic
acid (51)
5.1.82. 3-{2-({[1-(3,5-Dimethylphenyl)-3-methylbutyl]amino}-
carbonyl)-4-[(3-methoxyphenoxy)methyl]phenyl}propanoic
acid (41)
The titled compound was synthesized in the same manner as
described for 29 using 98r instead of 98a as a white powder. Yield
20% in three steps; 1H NMR (300 MHz, CDCl3) d 7.43–7.24 (m, 3H),
7.12–7.02 (m, 1H), 6.95 (s, 2H), 6.91 (s, 1H), 6.82–6.73 (m, 1H),
6.69–6.59 (m, 1H), 6.34 (d, J = 9.0 Hz, 1H), 5.23–5.12 (m, 1H),
4.95 (s, 2H), 3.11–2.93 (m, 2H), 2.72 (t, J = 7.5 Hz, 2H), 2.30 (s,
6H), 1.85–1.54 (m, 3H), 0.98 (d, J = 6.0 Hz, 6H); MS (APCI, Neg.)
m/e 508 (MꢁH)ꢁ; HRMS (Pos.) calcd for C30H34F2NO4: 510.2456;
found: 510.2454.
The titled compound was synthesized in the same manner as
described for 29 using 98m instead of 98a as a white powder.
Yield 77% in three steps; 1H NMR (300 MHz, CDCl3) d 7.46–7.38
(m, 2H), 7.32–7.12 (m, 2H), 6.95 (s, 2H), 6.90 (s, 1H), 6.60–6.49
(m, 3H), 6.28 (d, J = 8.1 Hz, 1H), 5.24–5.11 (m, 1H), 5.00 (s, 2H),
3.78 (s, 3H), 3.09–2.96 (m, 2H), 2.72 (t, J = 7.2 Hz, 2H), 2.31 (s,
6H), 1.87–1.52 (m, 3H), 0.98 (d, J = 6.0 Hz, 6H); MS (APCI, Neg.)
m/e 502 (MꢁH)ꢁ; HRMS (Pos.) calcd for C31H38NO5: 504.2750;
found: 504.2750.
5.1.88. 3-[4-[(3,5-Difluorophenoxy)methyl]-2-({[1-(3,5-dimeth-
ylphenyl)-3-methylbutyl]amino}carbonyl)phenyl]propanoic
acid (52)
5.1.83. 3-[4-[(2,3-Difluorophenoxy)methyl]-2-({[1-(3,5-dimeth-
ylphenyl)-3-methylbutyl]amino}carbonyl)phenyl]propanoic
acid (47)
The titled compound was synthesized in the same manner as
described for 29 using 98s instead of 98a as a white powder. Yield
47% in three steps; 1H NMR (300 MHz, CDCl3) d 7.42–7.35 (m, 2H),
7.30 (d, J = 7.5 Hz, 1H), 6.95 (s, 2H), 6.91 (s, 1H), 6.54–6.40 (m, 3H),
6.32 (d, J = 8.7 Hz, 1H), 5.17 (m, 1H), 4.97 (s, 2H), 3.12–2.94 (m,
2H), 2.73 (t, J = 7.3 Hz, 2H), 2.31 (s, 6H), 1.87–1.52 (m, 3H), 0.99
(d, J = 6.3 Hz, 6H); MS (APCI, Neg.) m/e 508 (MꢁH)ꢁ; HRMS (Pos.)
calcd for C30H34F2NO4: 510.2456; found: 510.2454.
The titled compound was synthesized in the same manner as
described for 29 using 98n instead of 98a as a white powder. Yield
50% in three steps; 1H NMR (300 MHz, CDCl3) d 7.45–7.38 (m, 2H),
7.29 (d, J = 7.2 Hz, 1H), 7.02–6.89 (m, 4H), 6.85–6.73 (m, 2H), 6.32
(d, J = 8.7 Hz, 1H), 5.17 (m, 1H), 5.10 (s, 2H), 3.07–2.95 (m, 2H), 2.73
(t, J = 7.2 Hz, 2H), 2.31 (s, 6H), 1.86–1.53 (m, 3H), 0.99 (d, J = 6.3 Hz,
6H); MS (APCI, Neg.) m/e 508 (MꢁH)ꢁ; HRMS (Pos.) calcd for
C30H34F2NO4: 510.2456; found: 510.2459.
5.1.89. 3-[(2-Oxo-2H-chromen-7-yl)methoxy]benzonitrile (100)
The titled compound was synthesized in the same manner as
described for 78 using 3-cyanophenol instead of phenol as a white
powder. Yield 83% in two steps; 1H NMR (300 MHz, CDCl3) d 7.72
(d, J = 9.6 Hz, 1H), 7.52 (d, J = 7.8 Hz, 1H), 7.45–7.20 (m, 6H), 6.45
(d, J = 9.6 Hz, 1H), 5.19 (s, 2H).
5.1.84. 3-[4-[(2,4-Difluorophenoxy)methyl]-2-({[1-(3,5-dimeth-
ylphenyl)-3-methylbutyl]amino}carbonyl)phenyl]propanoic
acid (48)
The titled compound was synthesized in the same manner as
described for 29 using 98o instead of 98a as a white powder.
Yield 18% in three steps; 1H NMR (300 MHz, CDCl3) d 7.44–
7.37 (m, 2H), 7.27 (d, J = 8.4 Hz, 1H), 6.98–6.72 (m, 6H),
6.31 (d, J = 8.7 Hz, 1H), 5.22–5.08 (m, 1H), 5.04 (s, 2H), 3.11–
2.94 (m, 2H), 2.71 (t, J = 7.8 Hz, 2H), 2.31 (s, 6H), 1.86–1.52
(m, 3H), 0.99 (d, J = 6.3 Hz, 6H); MS (APCI, Neg.) m/e 508
(MꢁH)ꢁ; HRMS (Pos.) calcd for C30H34F2NO4: 510.2456; found:
510.2457.
5.1.90. Methyl (2E)-3-{4-[(3-cyanophenoxy)methyl]-2-hydroxy-
phenyl}acrylate (101)
The titled compound was synthesized in the same manner as
described for 91 using 100 instead of 90 as a white powder. Yield
67%; 1H NMR (300 MHz, CDCl3) d 7.97 (d, J = 16 Hz, 1H), 7.49 (d,
J = 8.1 Hz, 1H), 7.42–7.12 (m, 4H), 6.96 (d, J = 7.8 Hz, 1H), 6.90 (s,
1H), 6.60 (d, J = 16 Hz, 1H), 5.05 (s, 2H), 3.82 (s, 3H).
5.1.85. 3-[4-[(2,5-Difluorophenoxy)methyl]-2-({[1-(3,5-dimeth-
ylphenyl)-3-methylbutyl]amino}carbonyl)phenyl]propanoic
acid (49)
5.1.91. Methyl 3-{4-[(3-cyanophenoxy)methyl]-2-hydroxyph-
enyl}propanoate (102)
The titled compound was synthesized in the same manner as
described for 92 using 101 instead of 91 as a colorless oil. Yield
65%; 1H NMR (300 MHz, CDCl3) d 7.40–6.85 (m, 7H), 5.01 (s, 2H),
3.70 (s, 3H), 2.91 (t, J = 6.3 Hz, 2H), 2.73 (t, J = 6.3 Hz, 2H).
The titled compound was synthesized in the same manner as
described for 29 using 98p instead of 98a as a white powder.
Yield 66% in three steps; 1H NMR (300 MHz, CDCl3) d 7.45–
7.38 (m, 2H), 7.29 (d, J = 8.2 Hz, 1H), 7.03 (m, 1H), 6.96 (s, 2H),
6.90 (s, 1H), 6.73 (m, 1H), 6.62 (m, 1H), 6.35 (d, J = 8.5 Hz, 1H),
5.17 (m, 1H), 5.05 (s, 2H), 3.11–2.93 (m, 2H), 2.81–2.62
(m, 2H), 2.31 (s, 6H), 1.84–1.52 (m, 3H), 0.99 (d, J = 6.3 Hz,
6H); IR (KBr) 3293, 3018, 2957, 2871, 1712, 1636, 1607, 1514,
1284, 1205, 1156, 1100, 834 cmꢁ1; MS (APCI, Neg.) m/e 508
(MꢁH)ꢁ; HRMS (Pos.) calcd for C30H34F2NO4: 510.2456; found:
510.2457.
5.1.92. 5-[(3-Cyanophenoxy)methyl]-2-(3-methoxy-3-oxopro-
pyl)benzoic acid (104)
The titled compound was synthesized in the same manner as
described for 83 using 102 instead of 81 as a brown solid. Yield
82% in two steps; 1H NMR (300 MHz, CDCl3) d 8.07 (s, 1H), 7.42–
7.20 (m, 6H), 5.09 (s, 2H), 3.67 (s, 3H), 3.33 (t, J = 7.8 Hz, 2H),
2.72 (t, J = 7.8 Hz, 2H).

M. Asada et al. / Bioorg. Med. Chem. 18 (2010) 1641–1658
1657
5.1.93. 3-[4-[(3-Cyanophenoxy)methyl]-2-({[3-methyl-1-(3-
methylphenyl)butyl]amino}carbonyl)phenyl]propanoic acid
(42)
(MꢁH)ꢁ; HRMS (Pos.) calcd for C31H35N2O6: 531.2495; found:
531.2497.
The titled compound was synthesized in the same manner as
described for 5 using 104 and 64b instead of 86 and 59a as a white
powder. Yield 61% in two steps; 1H NMR (300 MHz, CDCl3) d 7.43–
7.06 (m, 11H), 6.40 (d, J = 8.7 Hz, 1H), 5.26–5.16 (m, 1H), 5.04 (s,
2H), 3.13–2.97 (m, 2H), 2.74 (t, J = 7.5 Hz, 2H), 2.35 (s, 3H), 1.85–
1.58 (m, 3H), 0.99 (d, J = 6.3 Hz, 6H); IR (KBr) 3277, 2956, 2230,
5.2. Pharmacology
5.2.1. mEP1-4 receptor binding assay
Competitive binding studies were conducted using radiolabeled
ligands and membrane fractions prepared from Chinese hamster
ovary (CHO) cells stably expressing the prostanoid receptors
mEP1-4. Membranes from CHO cells expressing prostanoid recep-
tors were incubated with radiolabeled ligand (2.5 nM [3H]PGE2)
and test compounds at various concentrations in assay buffer
(10 mM KH2PO4–KOH buffer containing 1 mM EDTA, 10 mM
MgCl2, and 0.1 mM NaCl, pH 6.0). Incubation was carried out at
25 °C for 60 min except for mEP1 which was incubated for
20 min. Incubation was terminated by filtration through a What-
man GF/B filter. The filter was subsequently washed with ice-cold
buffer (10 mM KH2PO4–KOH buffer containing 0.1 mM NaCl, pH
6.0), and the radioactivity on the filter was measured in 6 mL of li-
quid scintillation (ACSII) mixture with a liquid scintillation coun-
ter. Nonspecific binding was achieved by adding excess amounts
of unlabeled PGE2 in assay buffer. The half maximal inhibitory con-
centration of specific binding (IC50 value) was estimated from the
regression curve. The Ki value (M) was calculated according to
the following equation:
1709, 1638, 1534, 1491, 1290, 1262, 1156, 1023, 787, 681 cmꢁ1
;
MS (APCI, Neg.) m/e 483 (MꢁH)ꢁ; HRMS (Pos.) calcd for
C30H33N2O4: 485.2440; found: 485.2437.
5.1.94. 3-[4-[(3-Cyanophenoxy)methyl]-2-({[1-(3-methoxy-
phenyl)-3-methylbutyl]amino}carbonyl)phenyl]propanoic acid
(43)
The titled compound was synthesized in the same manner as
described for 5 using 104 and 64d instead of 86 and 59a as a white
powder. Yield 55% in two steps; 1H NMR (300 MHz, CDCl3) d 7.42–
7.15 (m, 8H), 6.95 (d, J = 7.8 Hz, 1H), 6.91 (m, 1H), 6.81 (dd, J = 8.4,
2.7 Hz, 1H), 6.45 (d, J = 8.1 Hz, 1H), 5.22 (m, 1H), 5.03 (s, 2H), 3.81
(s, 3H), 3.02 (t, J = 7.2 Hz, 2H), 2.74 (t, J = 7.2 Hz, 2H), 1.83–1.58 (m,
3H), 0.98 (d, J = 6.3 Hz, 6H); IR (KBr) 3278, 2957, 2229, 1704, 1639,
1579, 1535, 1490, 1433, 1290, 1263, 1161, 1046, 818, 783,
680 cmꢁ1; MS (APCI, Neg.) m/e 499 (MꢁH)ꢁ; HRMS (Pos.) calcd
for C30H33N2O5: 501.2389; found: 501.2393.
Ki ¼ IC50=ð1 þ ½Lꢃ=KdÞ
where [L] is the concentration of radiolabeled ligand, and Kd is the
dissociation constant of radiolabeled ligand for the prostanoid
receptor of interest.
5.1.95. 3-[4-[(3-Cyanophenoxy)methyl]-2-({[1-(4-fluoroph-
enyl)-3-methylbutyl]amino}carbonyl)phenyl]propanoic acid
(44)
The titled compound was synthesized in the same manner as
described for 5 using 104 and 59c instead of 86 and 59a as a white
powder. Yield 61% in two steps; 1H NMR (300 MHz, DMSO-d6) d
9.26 (br s, 1H), 7.57–7.26 (m, 9H), 7.18–7.06 (m, 2H), 5.13 (s,
2H), 5.09–4.97 (m, 1H), 2.81 (t, J = 7.2 Hz, 2H), 2.42 (t, J = 7.2 Hz,
2H), 1.80–1.52 (m, 2H), 1.48–1.37 (m, 1H), 0.91 (t, J = 6.2 Hz, 3H),
0.89 (t, J = 6.2 Hz, 3H); MS (APCI, Neg.) m/e 489 (MꢁH)ꢁ; HRMS
(Pos.) calcd for C29H30FN2O4: 489.2190; found: 489.2194.
5.2.2. mEP3 receptor antagonist activity
To confirm that test compounds antagonized the mEP3 recep-
tor and to estimate the extent of antagonism for the mEP3 recep-
tor,
a functional assay was performed by measuring PGE2-
stimulated increases in intracellular Ca2+. The cells expressing
mEP3
a
receptor were seeded at 1 ꢂ 104 cells/well in 96 well
plates and cultured for two days with 10% FBS (fetal bovine ser-
um)/minimum essential medium Eagle alpha modification
(
a
MEM) in an incubator (37 °C, 5% CO2). The cells in each well
were rinsed with phosphate buffer (PBS(ꢁ)), and load buffer
(10% FBS/ MEM containing 5 M of Fura 2/AM, 20 M of indo-
5.1.96. 3-[4-[(3-Cyanophenoxy)methyl]-2-({[1-(4-fluoro-3-me-
thylphenyl)-3-methylbutyl]amino}carbonyl)phenyl]propanoic
acid (45)
a
l
l
methacin, and 2.5 mM of probenecid) was added. After incubation
for 1 h, the cells in each well were rinsed with assay buffer
(Hank’s balanced salt solution (HBSS) containing 1% (w/v) BSA,
The titled compound was synthesized in the same manner as
described for 5 using 104 and 64i instead of 86 and 59a as a white
powder. Yield 57% in two steps; 1H NMR (300 MHz, CDCl3) d 7.42–
7.35 (m, 3H), 7.31–7.25 (m, 2H), 7.21–7.11 (m, 4H), 6.96 (t,
J = 8.7 Hz, 1H), 6.46 (d, J = 8.4 Hz, 1H), 5.17 (m, 1H), 5.03 (s, 2H),
3.06–2.95 (m, 2H), 2.76–2.64 (m, 2H), 2.26 (d, J = 1.5 Hz, 3H),
1.81–1.53 (m, 3H), 0.97 (d, J = 6.6 Hz, 6H); IR (KBr) 3284, 2957,
2231, 1710, 1637, 1598, 1578, 1534, 1503, 1432, 1328, 1291,
1262, 1211, 1157, 1025, 942, 826, 788, 758, 681 cmꢁ1; MS (APCI,
Neg.) m/e 501 (MꢁH)ꢁ; HRMS (Pos.) calcd for C30H32FN2O4:
503.2346; found: 503.2342.
2
lM of indomethacin, 2.5 mM of probenecid, and 10 mM of
HEPES–NaOH) twice. Then 90 L of assay buffer was added to
l
each well and the cells were incubated in the dark at room tem-
perature for 1 h. After the addition of a solution containing test
compound (30 lL) and PGE2 (30 lL), which were prepared with
assay buffer, the intracellular calcium concentration was mea-
sured with a fluorescence drug screening system (FDSS-3000,
Hamamatsu Photonics). The fluorescence intensities emitted at
500 nm using excitation wavelengths of 340 nm and 380 nm were
measured. The percent inhibition from the increase in the intra-
cellular Ca2+ concentration induced by PGE2 (10 nM) was calcu-
lated relative to the maximum Ca2+ concentration that occurred
in the absence of the test compound (100%). This was then used
to estimate the IC50 value.
5.1.97. 3-[4-[(3-Cyanophenoxy)methyl]-2-({[1-(3,4-dimethoxy-
phenyl)-3-methylbutyl]amino}carbonyl)phenyl]propanoic acid
(46)
The titled compound was synthesized in the same manner as
described for 5 using 104 and 59e instead of 86 and 59a as a white
powder. Yield 72% in two steps; 1H NMR (300 MHz, CDCl3) d 7.44–
7.34 (m, 3H), 7.32–7.24 (m, 2H), 7.20–7.14 (m, 2H), 6.94–6.88 (m,
2H), 6.84 (d, J = 8.7 Hz, 1H), 6.42 (d, J = 8.4 Hz, 1H), 5.20 (m, 1H),
5.02 (s, 2H), 3.88 (s, 3H), 3.86 (s, 3H), 3.01 (t, J = 8.1 Hz, 2H), 2.73
(t, J = 8.1 Hz, 2H), 1.90–1.50 (m, 3H), 0.99 (d, J = 6.6 Hz, 6H); IR
(KBr) 3299, 2956, 2230, 1734, 1635, 1596, 1519, 1464, 1368,
1327, 1261, 1144, 1025, 789, 681 cmꢁ1; MS (APCI, Neg.) m/e 529
5.2.3. Inhibitory effect of test compounds on the PGE2-induced
uterine contraction in pregnant rats
Fed pregnant rats were anesthetized with urethane (1.5 g/
5 mL/kg sc) and fixed in the dorsal position. A midline incision
was made in the lower abdomen and a small incision was made
near the cervical area of the right or left uterine horn, and a

1658
M. Asada et al. / Bioorg. Med. Chem. 18 (2010) 1641–1658
balloon catheter (Okamoto Medical Industry, for rats) was in-
serted between the uterine wall and the amnion. After suturing
the abdominal incision, the intraballoon pressure was loaded to
approximately 10 mm Hg. Uterine motility was recorded on a rec-
ticoder (WR3320 or WR3701, GRAPHTEC) via a pressure trans-
References and notes
1. (a) Coleman, R. A.; Grix, S. P.; Head, S. A.; Louttit, J. B.; Mallett, A.; Sheldrick, R. L.
G. Prostaglandins 1994, 47, 151; (b) Negishi, M.; Sugimoto, Y.; Ichikawa, A. J.
Lipid Mediat. Cell Signal. 1995, 12, 379.
2. Sorbera, L. A.; Bozzo, J.; Rosa, E.; Dulsat, C. Drugs Future 2008, 33, 455.
3. Breyer, M. D.; Hebert, R. L.; Breyer, R. M. Curr. Opin. Invest. Drugs 2003, 4, 1343.
4. Cameron, K. O.; Lefker, B. A.; Ke, H. Z.; Li, M.; Zawistoski, M. P.; Tjoa, C. M.;
Wright, A. S.; DeNinno, S. L.; Paralkar, V. M.; Owen, T. A.; Yu, L.; Thompson, D. D.
Bioorg. Med. Chem. Lett. 2009, 19, 2075.
5. Singh, J.; Zeller, W.; Zhou, N.; Hategen, G.; Mishra, R.; Polozov, A.; Yu, P.; Onua,
E.; Zhang, J.; Zembower, D.; Kiselyov, A.; Ramirez, J. L.; Sigthorsson, G.;
Bjornsson, J. M.; Thorsteinsdottir, M.; Andresson, T.; Bjarnadottir, M.;
Magnusson, O.; Fabre, J. E.; Stefansson, K.; Gurney, M. E. ACS Chem. Biol.
2009, 4, 115.
6. Ohta, C.; Kuwabe, S.; Shiraishi, T.; Shinohara, I.; Araki, H.; Sakuyama, S.;
Makihara, T.; Kawanaka, Y.; Ohuchida, S.; Seko, T. J. Org. Chem. 2009, 74, 8298.
7. RaQualia Phrma Inc. Home Page. http://www.raqualia.co.jp/.
8. Just, S.; Arndt, K.; Weiser, T.; Doods, H. Drug Discovery Today Dis. Mech. 2006, 3,
327.
9. Asada, M.; Obitsu, T.; Nagase, T.; Tanaka, M.; Yamaura, Y.; Takizawa, H.;
Yoshikawa, K.; Sato, K.; Narita, M.; Ohuchida, S.; Nakai, H.; Toda, M. Bioorg.
Med. Chem. 2010, 18, 80.
10. Backes, B. J.; Dragoli, D. R.; Ellman, J. A. J. Org. Chem. 1999, 64, 5472.
11. Rodriques, K. E.; Basha, A.; Summers, J. B.; Broocks, D. W. Tetrahedron Lett.
1988, 29, 3455.
12. Satoh, T.; Nanba, K.; Suzuki, S. Chem. Pharm. Bull. 1971, 19, 817.
13. Cohen, B. J.; Karoly-Hafeli, H.; Patchornik, A. J. Org. Chem. 1984, 49, 922.
14. (a) Senior, J.; Marshall, K.; Sangha, R.; Baxter, G. S.; Clayton, J. K. Br. J. Pharmacol.
1991, 102, 747; (b) Goureau, O.; Tanfin, Z.; Marc, S.; Harbon, S. Am. J. Physiol.
1992, 263, C257.
ducer (Life Kit DX-360, Nihon Kohden Corp.) and
a strain
pressure amplifier (AP-601G, Nihon Kohden Corp.). After sponta-
neous uterine motility was kept at a stable level, a test compound
(5 mL/kg in 0.5% methylcellulose (MC)) or vehicle (0.5% MC) was
intraduodenally administrated. After 30 min, an increased uterine
contraction was elicited by an intravenous administration of PGE2
(30 lg/kg). Subtraction of the area under the uterus pressure–
time curve (AUC) for 10 min before PGE2 administration from
the AUC for 10 min after PGE2 administration was determined
to be the increased uterine contraction (=DS). The inhibitory ef-
fect of a test compound (% inhibition) was calculated according
to the following equation:
Inhibitory effect ð% inhibitionÞ
¼ ½
ꢄ 100
where S (test compound) is an increased uterine contraction of
administration of a test compound and S (vehicle) is an increased
uterine contraction of administration of vehicle.
D
S ðvehicleÞ ꢁ
D
S ðtest compoundÞꢃ=
D
S ðvehicleÞ
D
D