Novel inhibitors of 17β-hydroxysteroid dehydrogenase type 1: Templates for design

Article abstract of DOI:10.1016/j.bmc.2008.02.059

The 17β-hydroxysteroid dehydrogenases (17β-HSDs) catalyze the interconversion between the oxidized and reduced forms of androgens and estrogens at the 17 position. The 17β-HSD type 1 enzyme (17β-HSD1) catalyzes the reduction of estrone (E1) to estradiol a

Full text of DOI:10.1016/j.bmc.2008.02.059

Available online at www.sciencedirect.com
Bioorganic & Medicinal Chemistry 16 (2008) 4438–4456
Novel inhibitors of 17b-hydroxysteroid dehydrogenase
type 1: Templates for design
Gillian M. Allan,a Nigel Vicker,a Harshani R. Lawrence,a Helena J. Tutill,b
Joanna M. Day,b Marion Huchet,c Eric Ferrandis,c Michael J. Reed,b
Atul Purohitb and Barry V. L. Pottera,*
aMedicinal Chemistry, Department of Pharmacy and Pharmacology and Sterix Ltd, University of Bath,
Claverton Down BA2 7AY, UK
bEndocrinology and Metabolic Medicine and Sterix Ltd, Faculty of Medicine, Imperial College London,
St. Mary’s Hospital, London W2 1NY, UK
cIPSEN System Biology, 91966 Les Ulis, France
Received 19 November 2007; revised 12 February 2008; accepted 19 February 2008
Available online 7 March 2008
Abstract—The 17b-hydroxysteroid dehydrogenases (17b-HSDs) catalyze the interconversion between the oxidized and reduced
forms of androgens and estrogens at the 17 position. The 17b-HSD type 1 enzyme (17b-HSD1) catalyzes the reduction of estrone
(E1) to estradiol and is expressed in malignant breast cells. Inhibitors of this enzyme thus have potential as treatments for hormone
dependent breast cancer. Syntheses and biological evaluation of novel non-steroidal inhibitors designed to mimic the E1 template
are reported using information from potent steroidal inhibitors. Of the templates investigated biphenyl ethanone was promising and
led to inhibitors with IC50 values in the low micromolar range.
ꢀ 2008 Elsevier Ltd. All rights reserved.
1. Introduction
tion of estrone sulfatase.2 Estrone sulfatase inhibitors
have also been investigated and are now progressing
into clinical trials.3–5
Breast cancer is one of the most common cancers in wo-
men with an estimated global mortality of around
500,000 deaths per year. Of these breast tumors a large
proportion are initially hormone-responsive with circu-
lating estrogens playing a vital role in their growth. Ste-
roidogenic enzyme inhibitors can reduce circulating and
tissue levels of active estrogens by blocking their biosyn-
thetic pathways and thus can represent an effective treat-
ment for hormone dependent breast cancer (HDBC).
Estrone itself, however, is not the most potent human
estrogen and, while inhibitors of E1 formation have
reached an advanced stage of use and development, an-
other attractive target for the treatment of HDBC is
inhibition of 17b-hydroxysteroid dehydrogenase type 1
(17b-HSD1).
This enzyme is one of a class of enzymes known as the
17b-hydroxysteroid dehydrogenases (17b-HSDs) that
catalyze the interconversion between the oxidized and
reduced forms of androgens and estrogens at the 17 po-
sition. Although reversible, their activity is mainly unidi-
rectional and thus they can be classified as oxidative or
reductive. Thirteen members of this enzyme family have
been identified to date, eleven of which exist in humans
where they regulate the bioavailability of active andro-
gens and estrogens.6,7 While all require NAD(P)H or
NAD(P)+ as cofactor, each type has a selective substrate
affinity, directional activity, and a particular tissue
distribution.
Aromatase inhibitors, which prevent the conversion of
androgens into estrogens, are currently used as an adju-
vant therapy to treat HDBC.1 It has been proposed,
however, that a more important source of estrone (E1)
in breast tumors is the body’s reservoir of estrone 3-O-
sulfate (E1S), which can be converted to E1 by the ac-
Keywords: Hydroxysteroid dehydrogenase; 17b-HSD1; 17b-HSD2;
Breast cancer.
*
Corresponding author. Tel.: +44 1225 386639; fax: +44 1225
386114; e-mail: B.V.L.Potter@bath.ac.uk
0968-0896/$ - see front matter ꢀ 2008 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmc.2008.02.059

G. M. Allan et al. / Bioorg. Med. Chem. 16 (2008) 4438–4456
4439
The 17b-HSD1 enzyme, which has a preferentially
reductive activity using NADPH as cofactor,8,9 is
responsible for the reduction of the keto group of the
weakly active E1 to give the most potent of the human
estrogens, 17b estradiol (E2).
the E2 skeleton,21 novel hybrid inhibitors of 17b-
HSD122 and data for C6-(N,N-butyl-methyl-heptana-
mide) derivatives of E1 and E223 with a 6b-E2 deriva-
tive, which shows 82% inhibition of 17b-HSD1 at
1 lM and 29% inhibition at 0.1 lM in an assay using in-
tact T-47D cells. Patents detailing steroidal inhibitors
have been published by our group,24 Solvay Pharmaceu-
ticals25,26 and Schering AG.27,28
The enzyme is expressed in many steroidogenic tissues,
including breast tissue, and has been found to be active
in malignant breast cells.10,11 Estradiol is known to stim-
ulate the growth and development of HDBC12; therefore
inhibition of the final step in the synthesis of E2, by the
design of selective inhibitors of 17b-HSD1, is an attrac-
tive option for the treatment of HDBC. Some progress
has recently been made by our group in proving the
in vivo validity of this concept.13
Less has been reported about non-steroidal inhibitors of
17b-HSD1. A patent filed by Solvay Pharmaceuticals
details thiopyrimidone inhibitors,29 of which the most
potent has an IC50 of 0.6 lM in a purified enzyme assay.
Recently, phenyl ketone- and biphenyl ketone-based
compounds have been reported to show moderate inhi-
bition of 17b-HSD1, with the best showing 46% inhibi-
tion at 100 lM in an enzyme-based assay.30 As part of
our approach to developing non-steroidal inhibitors,
we have investigated different possible mimics of the
E1 skeleton and different areas of expansion from these.
We report here a study of various templates to develop
this new and growing area. In particular, we envisaged
synthesizing non-steroidal mimics of our most potent
steroidal inhibitors such as 1 (Fig. 1), which has an
IC50 of 27 nM in an assay using intact T-47D cells.31–33
As steroids are quite hydrophobic a non-steroidal
template may give inhibitors with an improved PK
profile.
The 17b-HSD1 enzyme consists of 327 amino acid resi-
dues, with a subunit mass of ꢀ35 kDa, and exists as a
homodimer.14 Much crystallographic information has
been determined, including that for the enzyme in its na-
tive form,15 in complex with E2 and NADP,16 with E2
alone,17 with equilin and NADP,18 and with the inhibi-
tor EM-1745.19 This structural information is a useful
aid for identifying potential inhibitors of 17b-HSD1
using in silico techniques.
Inhibitors of 17b-HSD1 have been reported by several
groups and this field has been reviewed by Poirier.20
Common structural features can be identified which
aid binding at the active site. These include a phenol,
which can undergo bifurcated hydrogen bonding to
His221 and Glu282 residues of the protein, and a hydro-
phobic scaffold which inhabits the hydrophobic area in
the active site.
2. Results and discussion
2.1. Synthesis
Our search for non-steroidal inhibitors of 17b-HSD1 be-
gan with an investigation of possible scaffolds, which
might replace the E1 skeleton. It was decided initially
to keep the phenol and ketone functionalities, since
these are known to be important for binding. An inves-
tigation of biphenyl ethanone-type systems with differ-
ent linkers between the phenyl rings34 showed that
those with just the C–C linker (e.g., 2 Scheme 1) showed
activity. This compound and the others evaluated in this
paper are listed in Tables 1–4.
Most of the inhibitors of 17b-HSD1 reported to date are
based on the steroid scaffold, with expansion from the 6,
15, 16, and 17 positions. Poirier et al. have reported a
number of inhibitors. These include E2 derivatives bear-
ing a short side chain at the C17a and C16a positions on
N
O
O
NH
Compound 2 was synthesized by a Suzuki coupling of 4-
hydroxyphenyl boronic acid to 4-bromoacetophenone
(Scheme 1). This reaction was performed under micro-
wave conditions at 150 ꢁC for 10 min to give an
unoptimized yield, after purification by flash chroma-
HO
Figure 1. Potent steroidal inhibitor of 17b-HSD1.
1
O
O
Y
X
B(OH)2
a
+
Y
Br
X
2
3
4
X=OH, Y=H
X=OMe, Y=H
X,Y=methylene dioxy
Scheme 1. Reagents and conditions: (a) Pd(OAc)2, K2CO3, Bu4NBr, EtOH/H2O, lW 150 ꢁC.

4440
G. M. Allan et al. / Bioorg. Med. Chem. 16 (2008) 4438–4456
Table 1. Inhibition of 17b-HSD type 1 and type 2 by non-steroidal mimics of E1 based on the biphenyl ethanone templatea,b
Structure
Compound
Inhibition of type 1 (% @ 10 lM)
Inhibition of type 2 (% @ 10 lM)
Type 1 (IC50 lM)
O
O
O
2
97
nd
3.7
HO
O
3
4
Inactive
Inactive
nd
nd
nd
nd
O
O
O
O
O
O
O
8
Inactive
nd
51
nd
nd
nd
nd
5.4
nd
3.7
nd
O
HO
O
16
73
9
Inactive
17
24
89
HO
O
Inactive
O
25
27
Inactive
Inactive
nd
nd
nd
nd
HO
O
O
28
31
86
71
nd
nd
4.8
9.9
O
HO
O
HO
a Mean of at least two measurements with typically a SD or spread of 14%.
b nd, not determined.

G. M. Allan et al. / Bioorg. Med. Chem. 16 (2008) 4438–4456
4441
Table 2. Inhibition of 17b-HSD type 1 and type 2 by non-steroidal mimics of E1 based on the biphenyl indanone templatea,b
Structure
Compound
Inhibition of type 1 (% @ 10 lM)
Inhibition of type 2 (% @ 10 lM)
Type 1 (IC50 lM)
O
O
O
O
10
Inactive
nd
nd
1.7
nd
2.0
nd
2.9
nd
O
HO
O
18
11
19
12
20
32
81
17
nd
48
nd
24
nd
Inactive
86
HO
O
56
F
O
O
75
F
HO
O
Inactive
a Mean of at least two measurements with typically a SD or spread of 15%.
b nd, not determined.
tography, of 28%. In the same manner compounds 3 and
4 were synthesized from 4-methoxyphenyl boronic acid
and 3,4-(methylenedioxy)phenyl boronic acid in yields
of 30% and 77%, respectively.
effect of pushing the aromatic rings further out of plane
from each other, the tricyclic compound 28, known from
the literature, was synthesized (Scheme 4), to investigate
the effect of forcing the aromatic rings closer to planar.
It was found that the acylation proceeded better using
methyl protection of the phenol, rather than acetyl.
The commercially available 2-hydroxyfluorene was
therefore O-methylated, acylated, and then demethylat-
ed to give 28.
Alignment studies confirmed that molecule 2 is similar
in length to E1, as can be seen in Figure 2, and a number
of alignment and shape similarity studies were per-
formed to investigate possible scaffolds.
Altogether, a number of substitutions from the biphenyl
template were investigated: these are shown in Schemes
2 and 3. The indanone biphenyl systems were synthe-
sized with the aim of the five-membered ring mimicking
the D-ring on E1; tetralones were synthesized in view of
the activities reported by Gege et al. for D-homo-estra-
1,3,5(10)-trienes.27 The boronic acids containing alkyl
substituents which are not commercially available were
synthesized from the corresponding bromophenyl com-
pounds using n-butyl lithium and trimethyl borate. Hav-
ing synthesized compounds 17 and 25 to investigate the
Shape similarity studies also suggested that an ethyl sub-
stituent next to the ethanone moiety may be able to oc-
cupy the same area in space as the C-18 methyl group of
E1. It was observed that a methyl substituent would not
be in the correct orientation as it would be planar to the
aromatic ring. An ethyl, however, being more flexible,
might be able to occupy the C-18 niche in the active site.
Molecule 31 was therefore synthesized as shown in
Scheme 5. The Suzuki coupling of 4-methoxyphenylbo-
ronic acid to 1-bromo-3-ethyl benzene progressed well,
giving a 75% yield after chromatography and recrystal-

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G. M. Allan et al. / Bioorg. Med. Chem. 16 (2008) 4438–4456
Table 3. Inhibition of 17b-HSD type 1 by non-steroidal mimics of E1
cial. The route to these amides is shown in Scheme 6.
The acid side chains were incorporated by acylation of
bromobenzene or bromotoluene with succinic anhydride
or 2,2-dimethyl succinic anhydride in high yield. The
resulting oxo-butyric acids were then subjected to Suzu-
ki couplings, with the resulting biphenyl oxo-butyric
acids being obtained in yields of about 60%. It was
envisaged that the amide couplings would proceed as ex-
pected and, indeed for the straight side chain, amides
were obtained in the region of 30% yield. For the bis-
methylated side chain, however, these conditions re-
sulted in cyclization to give a lactone which was ob-
tained in 27% yield, with no amide being isolated. This
route was improved by using acetyl chloride to give
the cyclic product in 56% yield, which could then be
heated with amine to give the desired amide product.
Demethylation using BBr3 then gave the desired phenols
in average yield of 47%.
based on the biphenyl tetralone templatea,b
Structure
Compound
% @ 10 lM
IC50
(lM)
O
O
O
O
13
21
14
22
Inactive
nd
O
HO
O
89
71
51
15.6
8.3
nd
In the indanone series the side chain was attached to 11
by the reaction with ethyl bromoacetate using LDA
(Scheme 7). Saponification of the ester gave 16% yield
of the acid 57 over two steps (the bis-alkylated product
being separable at the acid stage). Amide coupling of 57
with selected amines gave amides in an average 42%
yield and was followed by demethylation with an aver-
age yield of 36%. These compounds were evaluated bio-
logically as mixtures of enantiomers.
HO
a Mean of at least two measurements with typically a SD or spread of
15%.
b nd, not determined.
2.2. Biological results
lization. Acylation using acetic anhydride gave a mix-
ture of products, which were not separated by chroma-
tography. The mixture was then subjected to
demethylation using BBr3 to give the phenolic products,
which were then separable from the mixture, with the
desired product 31 being obtained in an unoptimized
yield of 20% over the two steps.
The compounds shown in Tables 1–4 were assessed for
their ability to inhibit 17b-HSD1 in an assay using intact
T-47D human breast cancer cells, by measuring the
amount of labeled E2 formed from the labelled natural
substrate, E1 at a substrate concentration of 2 nM per
well. The percentage of inhibition was then calculated
by comparison of conversion in the absence and pres-
ence of inhibitor. The percentages of inhibition achieved
for a 1 or 10 lM concentration of the inhibitors, as well
as the IC50 values for some of the more potent com-
pounds, are shown.
Finally, compound 32 (Table 2) was also synthesized, to
further investigate the necessity of a phenol for activity.
This was prepared according to the method of Zhuang
et al.36
From these scaffolds, two candidates were chosen from
which to synthesize mimics of potent inhibitor 1: tem-
plate 16 and template 19. It was decided that since the
ethyl substituent adjacent to the phenol is not usually
detrimental to activity and may hinder binding to the
estrogen receptor, thus reducing estrogenicity, then this
substituent could be incorporated from the outset.
Although non-steroidal inhibitors may not be estrogenic
an ethyl group next to the phenol moiety may retard po-
tential metabolism at this site. A small library of amides
was synthesized based on the biphenyl ethanone tem-
plate, to investigate any possible effect of chain length,
position of the pyridyl nitrogen, and comparison of
pyridyl with the hydroxyethyl moiety. Two methyl
substituted biphenyl amides, 52 and 53, were also syn-
thesized to investigate further the possibilities of expan-
sion from this position. An additional two compounds
containing a bis-methyl substituted side chain, 54 and
55, were also prepared for comparison to determine
whether rigidification of the side chain might be benefi-
The results showed that the biphenyl ethanone-based
molecules showed promising inhibition of 17b-HSD1,
with the best having an IC50 of around 3.7 lM. It can
be seen that methylation of the phenol was consistently
detrimental to activity. Similarly, the methylene dioxy
derivative 4 was found to be inactive. Incorporation of
an ethyl substituent adjacent to the hydroxyl gave com-
pound 16 of similar activity to 2, with the IC50 for 16
being 5.4 lM. Compound 16 was found to possess some
inhibitory activity against 17b-HSD2, showing 51%
inhibition of this enzyme at 10 lM.
Attempts to investigate the effect of molecule planarity
met with unexpected results. 17 Showed promising activ-
ity, with an IC50 of 3.7 lM; in contrast, 25 was shown to
be inactive. Of course, it is not possible to tell in which
orientation the rings are relative to each other or on
which side the substituents are interacting in the active
site. The tricyclic molecule 28, in which the aromatic
rings are fixed toward a more planar relative orienta-

G. M. Allan et al. / Bioorg. Med. Chem. 16 (2008) 4438–4456
4443
Table 4. Inhibition of 17b-HSD type 1 and type 2 by non-steroidal mimics of potent inhibitor 1a,b
Structure
Compound
Inhibition of type
1 (% at 1 lM)
Inhibition of type
2 (% @10 lM)
Type 1 (IC50 lM)
N
O
O
O
H
N
48
49
50
24
12
nd
nd
3.7
nd
nd
O
O
O
N
HO
HO
HO
H
N
Inactive
H
N
N
17
O
H
N
OH
N
51
52
23
21
nd
nd
nd
nd
O
HO
O
O
H
N
O
O
HO
HO
H
N
N
53
46
54
55
61
15
17
38
15
39
nd
nd
nd
nd
nd
nd
nd
1.8
nd
4.7
N
N
O
H
N
O
O
O
O
H
N
O
O
HO
HO
H
N
N
N
O
O
NH
N
HO
O
O
O
O
NH
NH
62
63
Inactive
Inactive
nd
nd
nd
nd
N
HO
HO
N
a Mean of at least two measurements with typically a SD or spread of 19%.
b nd, not determined.

4444
G. M. Allan et al. / Bioorg. Med. Chem. 16 (2008) 4438–4456
It appears for 31 as though the ethyl substituent next to
the acetyl is tolerated but with some loss of activity, sug-
gesting that space around this area is limited. Rotation
of the aromatic ring to place the ethyl on the bottom
side of the molecule would mimic a tetralone (vide
infra).
The indanone series proved promising, with the most
potent compound being the unsubstituted biphenyl
indanone 18, which has an IC50 of 1.7 lM. This com-
pound was also shown to be selective for 17b-HSD
type 1 over type 2, showing only 17% inhibition of type
2 at 10 lM. Addition of the ethyl moiety to give 19 did
not cause a significant decrease in potency (IC50
2.0 lM), but did result in a slight decrease in selectivity
(showing 48% inhibition of type 2 at 10 lM). Of the
fluorinated compounds 12 and 20, 12 was one of the
few methylated phenols which showed some activity
Figure 2. Alignment and shape similarity35: a comparison of E1
(green) with molecule 2 (purple).
tion, showed similar activity to 2, 16, and 17, with an
IC50 of 4.8 lM. This, then, was not any better than with
the aromatic rings untethered, and would add an extra
point of oxidation and therefore metabolism onto the
template.
O
O
O
( )n=0,1
Br
R2
R2
R2
c
a or b
R1
O
R1
R1
O
B(OH)2
( )n
( )n
or
O
+
HO
8
9
n=0, R1=Et, R2=H
n=0, R1=H, R2=Me
10 n=1, R1=R2=H
16 n=0, R1=Et, R2=H
17 n=0, R1=H, R2=Me
18 n=1, R1=R2=H
R1=R2=H
5
6
R1=Et, R2=H
R1=H, R2=Me
R1=F, R2=H
TfO
7
11 n=1, R1=Et, R2=H
12 n=1, R1=F, R2=H
13 n=2, R1=R2=H
19 n=1, R1=Et, R2=H
20 n=1, R1=F, R2=H
21 n=2, R1=R2=H
14 n=2, R1=Et, R2=H
22 n=2, R1=Et, R2=H
c
O
O
B(OH)2
a
+
BnO
Br
BnO
15
Scheme 2. Reagents and conditions: (a) Pd(PPh3)4, Na2CO3, EtOH/PhMe, D; (b) Pd(OAc)2, K2CO3, Bu4NBr, EtOH/H2O, lW 150 ꢁC; (c) BBr3,
DCM, ꢁ78 ꢁC–rt.
O
O
B(OH)2
c
a
b
+
O
Br
O
HO
O
23
24
25
Scheme 3. Reagents and conditions: (a) Pd(OAc)2, K2CO3, Bu4NBr, EtOH/H2O, lW 150 ꢁC; (b) Ac2O, AlCl3, DCM, ꢁ10 ꢁC–rt; (c) BBr3, DCM,
ꢁ78 ꢁC–rt.
a
c
b
O
O
HO
O
O
HO
27
28
26
Scheme 4. Reagents and conditions: (a) MeI, K2CO3, DMF, rt; (b) Ac2O, AlCl3, DCE, rt; (c) BBr3, DCM, ꢁ78 ꢁC–rt.

G. M. Allan et al. / Bioorg. Med. Chem. 16 (2008) 4438–4456
4445
O
B(OH)2
O
30
c
a
b
mixture
}
+
O
+
Br
O
29
O
O
O
O
+
HO
HO
31
Scheme 5. Reagents and conditions: (a) Pd(OAc)2, K2CO3, Bu4NBr, EtOH/H2O, lW 150 ꢁC; (b) Ac2O, AlCl3, ꢁ10 ꢁC–rt; (c) BBr3, DCM,
ꢁ78 ꢁC–rt.
R1
O
R2 R2
O
R1
R1
O
R2 R2
O
R2
R2
OH
a
OH
b
+
O
O
O
Br
B(OH)2
Br
33 R1=R2=H
34 R1=Me, R2=H
35 R1=H, R2=Me
O
36 R1=R2=H
37 R1=Me, R2=H
38 R1=H, R2=Me
O
R1
O
R1
O
R2 R2
R2 R2
O
NHR3
NHR3
c
f
O
R2=H
O
HO
40 R1=R2=H, R3=3'-pyridylmethyl
41 R1=R2=H, R3=2'-pyridylmethyl
42 R1=R2=H, R3=3'-pyridylethyl
43 R1=R2=H, R3=2'-methoxyethyl
44 R1=Me, R2=H, R3=3'-pyridylmethyl
45 R1=Me, R2=H, R3=3'-pyridylethyl
46 R1=H, R2=Me, R3=3'-pyridylmethyl
47 R1=H, R2=Me, R3=3'-pyridylethyl
48 R1=R2=H, R3=3'-pyridylmethyl
49 R1=R2=H, R3=2'-pyridylmethyl
50 R1=R2=H, R3=3'-pyridylethyl
51 R1=R2=H, R3=2'-hydroxyethyl
52 R1=Me, R2=H, R3=3'-pyridylmethyl
53 R1=Me, R2=H, R3=3'-pyridylethyl
54 R1=H, R2=Me, R3=3'-pyridylmethyl
55 R1=H, R2=Me, R3=3'-pyridylethyl
e
O
R2
R2
R1
O
c/d
R2=Me
O
39
Scheme 6. Reagents and conditions: (a) AlCl3, DCM, ꢁ10 ꢁC–rt; (b) Pd(PPh3)4, Na2CO3, EtOH/PhMe, D; (c) amine, DMAP, EDCI, DCM, rt; (d)
AcCl, NEt3, DCM, rt; (e) Amine, DCM, D; (f) BBr3, DCM, ꢁ78 ꢁC–rt.
(55% at 10 lM). It was hoped, therefore, that the
demethylated version might be highly potent; however,
the IC50 of the phenol 20 was found to be a moderate
2.9 lM.
The tetralones showed diminished activity compared to
the indanone and acetophenone series. This was a little
surprising since the six-membered homo D ring deriva-
tives of E1 are reported to be at least as active as the

4446
G. M. Allan et al. / Bioorg. Med. Chem. 16 (2008) 4438–4456
O
O
O
O
O
O
OH
a
b
O
O
O
11
56
57
O
O
O
O
NHR
NHR
d
c
O
HO
58 R=3'-pyridylmethyl
59 R=2'-pyridylmethyl
60 R=5'-methylpyrazin-2-yl
61 R=3'-pyridylmethyl
62 R=2'-pyridylmethyl
63 R=5'-methylpyrazin-2-yl
Scheme 7. Reagents and conditions: (a) LDA, ethyl bromoacetate, THF, ꢁ60 ꢁC–rt; (b) NaOH, THF/H2O, rt; (c) amine, EDCI, DMAP, NEt3,
DCM, rt; (d) BBr3, DCM, ꢁ78 ꢁC–rt.
E1 scaffold itself.27 It is possible, however, that the aro-
matic C ring mimic in our biphenyl series pushes the al-
kyl groups rigidly planar to the ring, in a direction which
is unfavorable compared to those which would be occu-
pied had such substituents been attached to a cyclohexyl
ring. For the tetralones containing the larger cyclohexa-
none ring, these differences in orientation could cause
more of a steric clash than for the indanone or ethanone
systems. Another surprising result was obtained for the
methylated biphenyl tetralone 14: this was the only
biphenyl template which was found to be more active
than its phenolic counterpart (Table 3).
best result was again observed for the 3-pyridyl methyl
amide 61, with an IC50 of 4.7 lM for the mixture of
enantiomers.
3. Summary and conclusions
We have identified biphenyl mimics of E1 and the potent
steroidal inhibitor 1 that are promising inhibitors of
17b-HSD1 for further elaboration. Similar to our steroi-
dal series we have attached an amide linker to the basic
biphenyl scaffold to obtain improved activity. In the
case of the biphenyl ethanone series, incorporation of
a bis-methylated linker leads to increased potency, pos-
sibly due to increased rigidification of the side chain, or
possibly due to beneficial hydrophobic interactions in
the active site. In this series there is an optimum length
for the side chain, and the 3-pyridyl amide seems consis-
tently better than 2-pyridyl. O-Methylation of the phe-
nol is usually detrimental to activity. This correlates
very well with the results for the C16-amide derivatives
of 2-ethyl E1, and thus implies that inhibitor 1 is being
mimicked in the desired way. Further improvements
from our steroidal series will be applied to these non-ste-
roidal templates to improve potency.
The results for the simple biphenyl-type templates 2, 16–
20 were thus all essentially similar, taking into account
standard deviation or spread. For further elaboration,
therefore, it was decided to use the simplest biphenyl
ethanone template, since extension to mimic inhibitor
1 would not involve the creation of a chiral center. It
was decided to incorporate the ethyl substituent immedi-
ately, with an intent to avoid problems of estrogenicity
caused by binding to estrogen receptor-a. A few ex-
panded indanones were also synthesized and tested as
mixtures of enantiomers, with the plan being to synthe-
size single enantiomers of any particularly active mole-
cule. The results for these are also shown in Table 4.
As in the steroidal series,37 the length of the chain and
position of the pyridyl nitrogen were investigated. Inter-
estingly, the best results were for the 3-pyridyl methyl
amides, as observed for the steroid series. However,
the extended biphenyl template is much more flexible
than molecule 1. It was decided, therefore, to increase
the rigidity of the side chain by incorporation of a bis-
methylated link. This proved to be successful, with an
increase in potency to give 54 with an IC50 of 1.8 lM.
Once again, the 3-pyridyl methyl amide proved better
than the 3-pyridyl ethyl motif. Compound 46, the
O-methyl intermediate of 54, was however found to be
much less active, showing only 17% inhibition of 17b-
HSD1 at 10 lM. It can be seen that incorporation of a
methyl substituent to give compounds 52 and 53 is not
beneficial to activity. In the indanone series 61–63 the
4. Experimental
4.1. General methods
All chemicals were used as received. Reactions using
anhydrous solvents were carried out under nitrogen.
Thin layer chromatography (TLC) was performed on
precoated plates (Merck TLC aluminum sheets silica
gel 60 F254). Product(s) and starting material(s) were de-
tected by either viewing under UV light and/or treating
with an ethanolic solution of phosphomolybdic acid fol-
lowed by heating. Flash column chromatography was
performed on silica gel (Sorbsil/Matrex C60) or using
Argonaut prepacked columns with a FlashmasterTM.
1H NMR (270 MHz or 400 MHz) and DEPT-edited
13C NMR (100.4 MHz) spectra were recorded with a

G. M. Allan et al. / Bioorg. Med. Chem. 16 (2008) 4438–4456
4447
Jeol Delta 270 or a Varian Mercury VX 400 NMR spec-
trometer, and chemical shifts are reported in parts per
million (ppm, d). HPLC analyses were performed on a
Waters Millennium 32 instrument equipped with a
Waters 996 PDA detector, using a Symmetry C18 reverse
phase column (4.6 · 150 mm) eluting with MeCN/H20
at 0.5 mL/min. FAB low and high resolution mass spec-
tra were recorded at the Mass Spectrometry Service
Center, University of Bath, using m-nitrobenzyl alcohol
(NBA) as the matrix; ES high resolution mass spectra
were recorded on a Bruker MicroTOF. ES and APCI
low resolution mass spectra were obtained on a Waters
Micromass ZQ. Elemental analyses were performed by
the Microanalysis Service, University of Bath. Melting
points were determined using a Stanford Research Sys-
tems Optimelt and are uncorrected. Microwave synthe-
ses were performed using a CEM Discoverꢂ instrument.
4.4.1. General procedure 1: Suzuki coupling using micro-
wave conditions. A mixture of bromo- or trifluorometh-
anesulfonyl-aromatic (0.5 mmol), the requisite boronic
acid (0.75 mmol), K2CO3 (0.172 g, 1.25 mmol), Bu4NBr
(0.161 g, 0.5 mmol), and Pd(OAc)2 (catalytic) in EtOH
(1.5 mL) and water (3.5 mL) was heated under microwave
conditions at 150 ꢁC for 10 or 20 min. Water (20 mL) was
added and the organics extracted into EtOAc (20 mL).
Purification by flash chromatography using gradient elu-
tion of hexane/EtOAc gave the title compound.
4.4.2. General procedure 2: Suzuki coupling using con-
ventional heating.
A solution of bromo-aromatic
(2.5 mmol) and the requisite boronic acid (2.8 mmol)
in PhMe (18 mL), EtOH (2 mL), and 2 M aq Na2CO3
(2 mL) was degassed by bubbling N2 through for
40 min. To this was added Pd(PPh3)4 (catalytic) and
the reaction was heated to reflux under N2 for 24 h.
The reaction was allowed to cool to rt before water
(100 mL) was added and the organics were extracted
into EtOAc (2· 100 mL). The extracts were combined
and concentrated under reduced pressure and the prod-
uct purified by flash chromatography using gradient elu-
tion of hexane/EtOAc.
4.2. Molecular modeling
Alignment and shape similarity studies were carried out
using The PyMOL Molecular Graphics System (2002),
http://www.pymol.org.35
4.3. Biological assays
4.4.3. General procedure 3: demethylation using BBr3. To
a stirred solution of O-methyl starting material in dry
DCM, cooled to ꢁ78 ꢁC (dry ice/acetone bath) was
added drop-wise BBr3 (1 M in DCM, 3 equiv) and the
reaction was allowed to warm slowly to rt overnight.
Water was added and the organics extracted into
DCM (2·). In cases where the product was soluble in
DCM, the extracts were combined and concentrated un-
der reduced pressure and the product purified by flash
chromatography using either hexane/EtOAc or DCM/
MeOH gradient elution. Where the product precipitated
upon addition of water this was collected by filtration
and washed with DCM and water. In cases where the
product was not soluble in DCM and did not precipitate
immediately (52–55), the aqueous layer was neutralized
with NaHCO3 to give a white powder, which was col-
lected by filtration and washed with water before drying
under high vacuum.
T-47D and MDA-MB-231 cells have previously been
shown to possess predominantly reductive 17b-HSD
type 1 or oxidative 17b-HSD type 2 activities,
respectively.38
4.3.1. Measurement of inhibition of 17b-HSD type 1. T-
47D human breast cancer cells were incubated with
3H-E1 at a concentration of 2 nM per well, in a 24-well
tissue culture plate, in the absence or presence of the
inhibitor (0.1 nM–10 lM). After incubation of the sub-
strate inhibitor for 30 min at 37 ꢁC, the products were
isolated from the mixture by extraction with Et2O
(4 mL), using 14C-E2 (5000 dpm) to monitor procedural
losses. Separation of 3H-E2 from the mixture was
achieved using TLC (DCM/EtOAc, 4:1 v/v) and the
3
3
mass of H-E2 produced was calculated from the H
counts detected and recovery of 14C-E2.
4.3.2. Measurement of inhibition of 17b-HSD type 2.
MDA-MB-231 human breast cancer cells were incu-
4.4.4. General procedure 4: amide coupling using a
GreenhouseTM synthesizer. To a stirred solution of 4-(30-
ethyl-40-methoxy-biphenyl)-4-oxo-butanoic acid 36 or
4-(30-Ethyl-40-methoxy-3-methyl-biphenyl-4-yl)-4-oxo-buty-
ric acid 37 (0.32 mmol) and NEt3 (60 lL) in dry DCM
(2 mL) under N2 was added a solution of EDCI
(0.192 g, 1 mmol) and DMAP (catalytic) in dry DCM
(2 mL) and the mixture was stirred for 40 min before
addition of amine (0.06 mL). The reaction was stirred
at rt for 24 h before quenching with NaHCO3 (satd
aq). The organic layer was separated and concentrated
under reduced pressure and the product purified by flash
chromatography using gradient elution of DCM to 5%
MeOH in DCM, followed by recrystallization from
DCM/hexane.
3
bated with H-E2 at a concentration of 2 nM per flask,
in the absence or presence of the inhibitor (0.1 nM–
10 lM). After incubation of the substrate inhibitor
for 3 h at 37 ꢁC, the products were isolated from the
mixture by extraction with Et2O (4 mL), using 14C-E1
(5000 dpm) to monitor procedural losses. Separation
of 3H-E1 from the mixture was achieved using TLC
(DCM/EtOAc, 4:1 v/v) and the mass of 3H-E1 produced
was calculated from the 3H counts detected and recovery
of 14C-E1.
4.4. Chemical synthesis
Compounds 6,39 7,40 32,36 and 3341 were prepared
according to the literature procedure, with physical
and spectroscopic data in agreement with literature re-
ported values.
4.4.4.1. 1-(40-Hydroxy-biphenyl-4-yl)-ethanone (2). Pre-
pared according to the General Procedure 1, heating
for 10 min (30 mg, 28%): mp 202–206 ꢁC [lit. 205–

4448
G. M. Allan et al. / Bioorg. Med. Chem. 16 (2008) 4438–4456
1
206 ꢁC42]; H NMR d (400 MHz, CD3OD) 2.59 (3H, s),
6.88 (2H, d, J = 8.6 Hz), 7.52 (2H, d, J = 8.6 Hz), 7.66
(2H, d, J = 8.2 Hz), 7.99 (2H, d, J = 8.2 Hz); 13C
NMR d (100 MHz, CD3OD) 24.6, 114.9, 125.4, 127.4,
128.1, 130.2, 134.3, 145.3, 157.2, 198.2; HPLC
tR = 3.59 min (>94%) 90% MeCN in H2O; LC/MS
(APCI) m/z 211.24 (MꢁH)ꢁ; HRMS (ES+) m/z Calcd
for C14H13O2 213.0910, found (M+H)+ 213.0910.
88%): mp 69–72 ꢁC; 1H NMR d (270 MHz, CDCl3)
1.23 (3H, t, J = 7.5 Hz), 2.62 (3H, s), 2.69 (2H, q,
J = 7.5 Hz), 3.87 (3H, s), 6.92 (1H, d, J = 8.2 Hz),
7.43–7.47 (2H, m), 7.64 (2H, d, J = 8.4 Hz), 7.99 (2H,
d, J = 8.4 Hz); 13C NMR d (100 MHz, CDCl3) 14.2,
23.5, 26.7, 55.5, 110.5, 125.7, 126.7, 127.9, 128.9,
131.9, 132.0, 133.2, 135.1, 145.8, 157.8, 197.9; HPLC
tR = 5.05 min (>99%) 80% MeCN in H2O; LC/MS
(APCI) m/z 254.09 (M+H)+; HRMS (FAB+) m/z Calcd
for C17H19O2 255.1380, found (M+H)+ 255.1384.
4.4.4.2. 1-(40-Methoxy-biphenyl-4-yl)-ethanone (3). Pre-
pared according to the General Procedure 1, heating for
20 min (77 mg, 68%): mp 153–155 ꢁC [lit. 153–154 ꢁC43];
1H NMR d (270 MHz, CD3OD) 2.61 (3H, s), 3.84 (3H,
s), 6.98 (2H, d, J = 8.6 Hz), 7.56 (2H, d, J = 8.2 Hz), 7.62
(2H, d, J = 8.2 Hz), 7.99 (2H, d, J = 8.2 Hz); HPLC
tR = 2.93 min (>96%) 90% MeCN in H2O; LC/MS (APCI)
m/z 227.0 (M+H)+; HRMS (ES+) m/z Calcd for C15H15O2
227.1067, found (M+H)+ 227.1077.
4.4.4.7. 1-(40-Methoxy-20-methyl-biphenyl-4-yl)-etha-
none (9). Prepared according to the General Procedure
1 using 2-methyl-4-methoxyphenyl boronic acid 6, heat-
1
ing for 10 min (yield 72%): mp 100–102 ꢁC; H NMR d
(270 MHz, CDCl3) 2.26 (3H, s), 2.63 (3H, s), 3.83 (3H,
s), 6.78–6.82 (2H, m), 7.15 (1H, d, J = 8.4 Hz), 7.39
(2H, d, J = 8.4 Hz), 7.98 (2H, d, J = 8.4 Hz); HPLC
tR = 2.42 min (>99%) 90% MeCN in H2O; LC/MS
(AP+) m/z 241.29 (M+H)+.
4.4.4.3. 1-(4-Benzo[1,3]dioxol-5-yl-phenyl)-ethanone (4).
Prepared according to the General Procedure 1, heating
for 10 min (90 mg, 75%): mp 132–134 ꢁC [lit. 140–
4.4.4.8. 5-(4-Methoxyphenyl)-indan-1-one (10). This
compound has been described in the literature.46 Pre-
pared according to the General Procedure 1, heating
for 20 min (yield 62%): mp 147–150 ꢁC; 1H NMR d
(270 MHz, CDCl3) 2.67–2.71 (2H, m), 3.12–3.16 (2H,
m), 3.83 (3H, s), 6.97 (1H, d, J = 8.8 Hz), 7.51–7.59
(4H, m), 7.76 (1H, d, J = 8.0 Hz); HPLC tR = 3.04 min
(>98%) 90% MeCN in H2O; LC/MS (APCI) m/z 239.0
(M+H)+; HRMS (ES+) m/z Calcd for C16H15O2
239.1067, found (M+H)+ 239.1071.
1
141 ꢁC44]; H NMR d (400 MHz, CDCl3) 2.59 (3H, s),
5.98 (2H, s), 6.87 (1H, d, J = 7.8 Hz), 7.06–7.09 (2H, m),
7.56 (2H, d, J = 8.6 Hz), 7.96 (2H, d, J = 8.6 Hz); 13C
NMR d (100 MHz, CDCl3) 26.5, 101.3, 107.4, 108.6,
120.9, 126.7, 128.8, 133.9, 135.3, 145.3, 147.8, 148.2,
197.6; HPLC tR = 4.34 min (>97%) 90% MeCN in H2O;
LC/MS (APCI) m/z 241.36 (M+H)+; HRMS (ES+) m/z
Calcd for C15H13O3 241.0859, found (M+H)+ 241.0858.
4.4.4.4. 3-Ethyl-4-methoxyphenylboronic acid (5). To
a stirred solution of 4-bromo-2-ethyl-1-methoxyben-
zene45 (4.59 g, 21 mmol) in dry THF (50 mL), cooled
to ꢁ78 ꢁC, was added slowly drop-wise (over 45 min)
n-BuLi (15 mL of a 1.6 M solution in hexanes,
24 mmol). The solution was stirred at ꢁ78 ꢁC for 2 h be-
fore trimethylborate (3.6 mL, 31.5 mmol) was added
drop-wise and the reaction was allowed to warm slowly
to rt with stirring overnight. The reaction was quenched
with 2 M HCl (50 mL) and the products extracted with
EtOAc (2· 50 mL). These extracts were combined and
concentrated under reduced pressure to give an oily sub-
stance. To this was added hexane followed by a small
amount of DCM and the resulting white precipitate
was collected by filtration and washed with hexane
(1.55 g, 41%); 1H NMR d (270 MHz, CDCl3) 1.27
(3H, t, J = 7.5 Hz), 2.73 (2H, q, J = 7.5 Hz), 3.90 (3H,
s), 6.60 (ꢀ1H, br s), 6.96 (1H, d, J = 8.4 Hz), 7.98
(1H, d, J = 1.5 Hz), 8.08 (1H, dd, J = 8.2, 1.7 Hz);
HPLC tR = 2.71 min (>99%) 90% MeCN in H2O; LC/
MS (APCI) m/z 179.04 (MꢁH)ꢁ.
4.4.4.9. 5-(3-Ethyl-4-methoxyphenyl)-indan-1-one (11).
Prepared according to the General Procedure 2 using 3-
ethyl-4-methoxyphenylboronic acid 5 (yield 65%): mp
100–102 ꢁC; H NMR d (270 MHz, CDCl3) 1.24 (3H,
t, J = 7.4 Hz), 2.66–2.74 (4H, m), 3.14–3.19 (2H, m),
3.87 (3H, s), 6.92 (1H, d, J = 9.1 Hz), 7.43–7.46 (2H,
m), 7.55–7.63 (2H, m), 7.78 (1H, d, J = 8.0 Hz);
EtOAc/hexanes, 3:7, Rf = 0.5; HPLC tR = 2.80 min
(>97%) 90% MeCN in H2O; LC/MS (ES+) m/z 267.4
(M+H)+; HRMS (ES+) m/z Calcd for C18H19O2
267.1380, found (M+H)+ 267.1380.
1
4.4.4.10. 5-(3-Fluoro-4-methoxyphenyl)-indan-1-one
(12). Prepared according to the General Procedure 1,
heating for 20 min (yield 25%): mp 130–131 ꢁC; 1H
NMR d (270 MHz, CDCl3) 2.70–2.75 (2H, m), 3.15–
3.20 (2H, m), 3.86 (3H, s), 6.90 (2H, d, J = 8.8 Hz),
7.54–7.62 (4H, m), 7.78 (1H, d, J = 8.0 Hz); HPLC
tR = 2.05 min (>95%) 90% MeCN in H2O; HRMS
(ES+) m/z 257.0981 (M+H)+, Calcd 257.0972 for
C16H14FO2.
4.4.4.5. 2-Methyl-4-methoxyphenyl boronic acid (6).
Preparation and H NMR as described by Mello and
1
4.4.4.11. 6-(4-Methoxy-phenyl)-3,4-dihydro-2H-naph-
thalen-1-one (13). This compound has been described in
the literature.47 Prepared according to the General Pro-
cedure 1 from trifluoro-methanesulfonic acid 5-oxo-
5,6,7,8-tetrahydro-naphthalen-2-yl ester 7, heating for
10 min (yield 58%): mp 127–128 ꢁC [lit. 126–127 ꢁC48];
1H NMR d (270 MHz, CDCl3) 2.09–2.19 (2H, m),
2.63–2.68 (2H, m), 2.97–3.01 (2H, m), 3.84 (3H, s),
6.97 (2H, d, J = 8.7 Hz), 7.40 (1H, s), 7.48 (1H, dd,
Finney.39
HPLC tR = 1.27 min (>99%) 90% MeCN in H2O; LC/
MS (APCI) m/z 164.76 (MꢁH)ꢁ.
4.4.4.6. 1-(30-Ethyl-40-methoxy-biphenyl-4-yl)-ethanone
(8). Prepared according to the General Procedure 2
using 3-ethyl-4-methoxyphenylboronic acid 5 (yield

G. M. Allan et al. / Bioorg. Med. Chem. 16 (2008) 4438–4456
4449
J = 8.2, 1.7 Hz), 7.55 (2H, d, J = 8.7 Hz), 8.06 (1H, d,
J = 8.2 Hz); HPLC tR = 2.38 min (>99%) 90% MeCN
in H2O; LC/MS (ES+) m/z 252.95 (M+H)+; HRMS
(ES+) m/z calcd for C17H17O2 253.1223, found
(M+H)+ 253.1222.
obtain pale yellow powder. This was purified by chro-
matography on SiO2 (EtOAc/hexanes gradient elution)
to afford the title compound (0.49 g, 50%) as a pale yel-
1
low solid; H NMR d (270 MHz, CD3OD) 2.70 (2H, t,
J = 5.6 Hz), 3.19 (2H, t, J = 5.4 Hz), 6.87–6.90 (2H,
m), 7.53–7.63 (3H, m), 7.70–7.72 (2H, m); HPLC
tR = 1.70 min (>95%) 90% MeCN in H2O; LRMS
(FAB+) m/z 225 (M+H)+.
4.4.4.12. 6-(3-Ethyl-4-methoxyphenyl)-3,4-dihydro-
2H-naphthalen-1-one (14). Prepared according to the
General Procedure 1 using 3-ethyl-4-methoxyphenylbo-
ronic acid 5, heating for 10 min (yield 25%, oil); 1H
NMR d (270 MHz, CDCl3) 1.24 (3H, t, J = 7.4 Hz),
2.11–2.20 (2H, m), 2.64–2.74 (4H, m), 2.98–3.03 (2H,
m), 3.87 (3H, s), 6.91 (1H, d, J = 8.9 Hz), 7.42–7.52
(4H, m), 8.07 (1H, d, J = 8.2 Hz); HPLC tR = 3.40 min
(>97%) 90% MeCN in H2O; LC/MS (ES+) m/z 281.11
(M+H)+; HRMS (ES+) m/z Calcd for C19H21O2
281.1536, found (M+H)+ 281.1535.
4.4.4.17. 5-(3-Ethyl-4-hydroxyphenyl)-indan-1-one (19).
Procedure as for 18, from 5-(3-ethyl-4-methoxyphenyl)-
indan-1-one 11 (0.178 g, 0.66 mmol) to give pale yellow
1
solid (0.122 g, 72%); H NMR d (270 MHz, CD3OD)
1.29 (3H, t, J = 7.4 Hz), 2.66–2.75 (4H, m), 3.17 (2H,
t, J = 5.4 Hz), 6.86 (1H, d, J = 8.1 Hz), 7.36 (1H, dd,
J = 8.1, 2.2 Hz), 7.41–7.42 (1H, m), 7.56 (1H, d,
J = 7.9 Hz), 7.63 (1H, s), 7.78 (2H, d, J = 7.9 Hz);
HPLC tR = 1.70 min (>96%) 80% MeCN in H2O; LC/
MS (APCI) m/z 213 (M+H)+.
4.4.4.13. 5-(-4-(Benzyloxy)-phenyl)-indan-1-one (15).
Prepared according to the General Procedure 2 (yield
1
75%); H NMR d (CDCl3, 270 MHz) 2.70–2.73 (2H, t,
4.4.4.18. 5-(3-Fluoro-4-hydroxyphenyl)-indan-1-one
(20). Prepared according to the General Procedure 3
from 5-(3-fluoro-4-methoxyphenyl)-indan-1-one 12.
Flash chromatography (DCM/MeOH, gradient elution)
followed by recrystallization from DCM/hexane gave
the title compound as a pale yellow solid (yield 36%):
mp >200 ꢁC (dec); 1H NMR d (270 MHz, CD3OD)
2.71 (2H, t, J = 3.9 Hz), 3.18–3.22 (2H, m), 7.01 (1H,
t, J = 8.6 Hz), 7.37 (1H, dd, J = 9.1, 2.9 Hz), 7.45 (1H,
dd, J = 12.6, 2.2 Hz), 7.62 (1H, d, J = 8.4 Hz), 7.71–
7.74 (2H, m); HPLC tR = 1.66 min (>94%) 90% MeCN
in H2O; LRMS (FAB+) m/z 242 (M)+; HRMS (FAB+)
m/z Calcd for C15H11FO2 243.0821, found (M+H)+
243.0820.
J = 4.2 Hz), 3.15–3.19 (2H, t, J = 5.6 Hz), 5.12 (2H, s),
7.07 (1H, d, J = 8.9 Hz), 7.28–7.37 (5H, m), 7.40–7.62
(4H, m), 7.77–7.80 (1H, d, J = 7.9 Hz); EtOAc/hexanes,
3:7, Rf = 0.5.
4.4.4.14. 1-(30-Ethyl-40-hydroxy-biphenyl-4-yl)-eth-
anone (16). Prepared according to the General Proce-
dure
3
from 1-(30-ethyl-40-methoxy-biphenyl-4-yl)-
ethanone 8 (yield 42%): mp 154–156 ꢁC; 1H NMR d
(400 MHz, CDCl3) 1.29 (3H, t, J = 7.5 Hz), 2.65 (3H,
s), 2.73 (2H, q, J = 7.5 Hz), 5.95 (1H, s), 6.91 (1H, d,
J = 8.1 Hz), 7.34–7.37 (1H, m), 7.43 (1H, d,
J = 2.1 Hz), 7.64 (2H, d, J = 8.4 Hz), 8.00 (2H, d,
J = 8.4 Hz); 13C NMR d (100 MHz, CDCl3) 14.0, 23.2,
26.6, 115.7, 125.8, 126.6, 128.3, 129.0, 130.7, 132.1,
134.9, 145.9, 154.2, 198.6; HPLC tR = 2.24 min (>98%)
90% MeCN in H2O; LC/MS(APCI) m/z 239.03
(MꢁH)ꢁ; HRMS (FAB+) m/z Calcd for C16H17O2
241.1229, found (M+) 241.1223.
4.4.4.19. 6-(4-Hydroxy-phenyl)-3,4-dihydro-2H-naph-
thalen-1-one (21). This compound has been described in
the literature.40 Prepared according to the General Proce-
dure 3 from 6-(4-methoxy-phenyl)-3,4-dihydro-2H-naph-
thalen-1-one 13. Flash chromatography using DCM to
5% MeOH in DCM gave the product not fully separated
from other fractions. The mixture was columned again
usinghexaneto30% EtOAcinhexane to givedifferentfrac-
tions withapproximatelythe sameRf. Thefirst of these was
found to be product (yield 22%): mp 208–211 ꢁC [lit. 208–
210 ꢁC40]; 1H NMR d (270 MHz, CDCl3) 2.03–2.08 (2H,
m), 2.57–2.62 (2H, m), 2.97–3.01 (2H, t, J = 5.9 Hz), 6.87
(2H, d, J = 8.6 Hz), 7.55–7.60 (4H, m), 7.88 (1H, d,
J = 8.9 Hz); 9.72 (1H, br s); HPLC tR = 1.81 min (>95%)
90% MeCN in H2O; LC/MS (ESꢁ) m/z 236.95 (MꢁH)ꢁ;
HRMS (ES+) m/z Calcd for C16H15O2 239.1067, found
(M+H)+ 239.1065.
4.4.4.15. 1-(40-Hydroxy-20-methyl-biphenyl-4-yl)-etha-
none (17). Prepared according to the General Procedure
3
from 1-(40-methoxy-20-methyl-biphenyl-4-yl)-etha-
none 9 (yield 13%): mp 117–119 ꢁC; 1H NMR d
(270 MHz, CDCl3) 2.23 (3H, s), 2.64 (3H, s), 5.03 (1H,
br s), 6.72–6.78 (2H, m), 7.10 (1H, d, J = 8.1 Hz), 7.39
(2H, d, J = 8.4 Hz), 7.98 (2H, d, J = 8.4 Hz); HPLC
tR = 1.72 min (>91%) 90% MeCN in H2O; LC/MS
(APꢁ) m/z 224.92 (MꢁH)ꢁ; HRMS (ES+) m/z Calcd
for C15H15O2 227.1067, found (M+H)+ 227.1072.
4.4.4.16. 5-(4-Hydroxyphenyl)-indan-1-one (18). This
compound has been described in the literature.46 To a
stirred suspension of 5-(4-benzyloxyphenyl)-indan-1-
one 15 (0.100 g, 0.44 mmol), cooled to ꢁ78 ꢁC, was
added BBr3 (1.0 M solution in DCM, 1.32 mL,
1.32 mmol) and the mixture stirred for 2 h until com-
plete by TLC analysis (EtOAc/hexanes, 3:7, Rf = 0.19).
The mixture was allowed to warm to room temperature,
water (20 mL) was added and the organics extracted
into EtOAc (2· 20 mL) and DCM (2· 20mL). The com-
bined extracts were dried (Na2SO4) and concentrated to
4.4.4.20. 6-(3-Ethyl-4-hydroxyphenyl)-3,4-dihydro-2H-
naphthalen-1-one (22). Prepared according to the Gen-
eral Procedure 3 from 6-(3-ethyl-4-methoxyphenyl)-
3,4-dihydro-2H-naphthalen-1-one 14. Columned using
DCM/MeOH then dissolved in MeOH, filtered, and fil-
trate concentrated (yield 23%): mp 202–206ꢁC; 1H
NMR d (270 MHz, CDCl3) 1.23 (3H, t, J = 7.5 Hz),
2.12–2.19 (2H, m), 2.63–2.71 (4H, m), 3.02–3.06 (2H,
m), 6.83 (1H, d, J = 8.2 Hz), 7.34–7.37 (1H, m), 7.42
(1H, d, J = 1.5 Hz), 7.51–7.54 (4H, m), 7.97 (1H, d,

4450
G. M. Allan et al. / Bioorg. Med. Chem. 16 (2008) 4438–4456
J = 8.7 Hz); HPLC tR = 1.99 min (>92%) 90% MeCN in
H2O LC/MS (ESꢁ) m/z 265.36 (MꢁH)ꢁ; HRMS (ES+)
m/z Calcd for C18H19O2 267.1380, found (M+H)+
267.1379.
lowed by MeI (41 lL, 0.66 mmol) and the reaction was
stirred at rt for 17 h. Water was added and the resulting
beige precipitate was collected by filtration. Recrystalli-
zation from DCM/hexane gave a brown powder which
was separated. The filtrate was columned using hexane
to 20% EtOAc to give the title compound as the first
fraction (yield 73%); 1H NMR d (270 MHz, CDCl3)
3.88 (5H, s), 6.96 (1H, dd, J = 8.3, 2.3 Hz), 7.11–7.12
(1H, m), 7.26 (1H, dt, J = 7.4, 1.3 Hz), 7.34–7.40 (1H,
m), 7.52 (1H, d, J = 7.1 Hz), 7.68–7.73 (2H, m); HPLC
tR = 2.74 min (>96%) 90% MeCN in H2O.
4.4.4.21. 40-Methoxy-2-methyl-biphenyl (23). This
compound has been described in the literature.49 A sus-
pension of 4-methoxyphenyl boronic acid (0.57 g,
3.75 mmol), 2-bromotoluene (0.3 mL, 2.5 mmol),
K2CO3 (0.86 g, 6.25 mmol), and Bu4NBr (0.805 g,
2.5 mmol) in EtOH (7.5 mL) and water (17.5 mL) was
degassed by bubbling N2 through for 30 min while heat-
ing to 80 ꢁC. To the resulting solution was added
Pd(OAc)2 (catalytic) and the reaction was heated at
80 ꢁC for 1h with vigorous stirring. The reaction mixture
was then allowed to cool before EtOAc (50 mL) was
added and the mixture was washed with 1 M NaOH
(aq) (2· 50 mL), water (2· 50 mL) ,and brine (2·
50 mL) before being concentrated under reduced pres-
sure. Flash chromatography (20 g column, Flashmaster
II) using a gradient elution of hexane to 10% EtOAc in
4.4.4.25. 1-(7-Methoxy-9H-fluoren-2-yl)-ethanone (27).
This compound is described in the literature.51 To a stir-
red solution of 26 (78 mg, 0.4 mmol) and Ac2O (0.1 mL)
in 1,2-dichloroethane (10 mL) was added AlCl3 (0.24 g)
and the reaction was stirred at rt for 24 h. The reaction
was quenched with 2 M HCl and the organic layer sep-
arated and concentrated under reduced pressure (yield
1
20%): mp 123–127 ꢁC [lit. 131–132 ꢁC47]; H NMR d
(270 MHz, CDCl3) 2.63 (3H, s), 3.86 (3H, s), 3.89 (2H,
br s), 6.95 (1H, dd, J = 8.4, 2.2 Hz), 7.10–7.11 (1H,
m), 7.70 (2H, d, J = 8.2 Hz), 7.72 (2H, d, J = 8.4 Hz),
7.94–7.98 (1H, m), 8.08 (1H, br s); HPLC tR = 2.31 min
(>99%) 90% MeCN in H2O; LC/MS (APꢁ) m/z 237.27
(MꢁH)ꢁ, 255.28; HRMS (ES+) m/z Calcd for
C16H15O2 239.1067, found (M+H)+ 239.1074.
1
hexane yielded the title compound (0.602 g, 80%); H
NMR d (270 MHz, CDCl3) 2.53 (3H, s), 4.01 (3H, s),
7.15–7.20 (2H, m), 7.43–7.51 (6H, m); HPLC
tR = 2.51 min (>92%) 90% MeCN in H2O; LC/MS
(ESꢁ) m/z 197.28 (MꢁH)ꢁ.
4.4.4.22. 1-(40-Methoxy-2-methyl-biphenyl-4-yl)-etha-
none (24). To a stirred solution of 40-methoxy-2-methyl-
biphenyl 23 (06.00 g, 3 mmol) in dry DCM (5 mL) was
added acetic anhydride (0.34 mL, 3.6 mmol) and the
solution was cooled to ꢁ10 ꢁC (ice/acetone bath). To
this was then added AlCl3 (0.800 g, 6 mmol) and the
reaction was allowed to warm slowly to rt with stirring
over 65 h. The reaction was quenched with 2 M HCl
(aq) and the organics extracted into DCM and concen-
trated under reduced pressure. Purification by flash
chromatography using hexane to 10% EtOAc in hexane
gave the product as the second fraction in 33% yield: mp
4.4.4.26. 1-(6-Hydroxy-9H-fluoren-2-yl)-ethanone (28).
Prepared according to the General Procedure 3 from 1-
(7-methoxy-9H-fluoren-2-yl)-ethanone 27 (yield 36%):
mp >190 ꢁC (dec) [lit. 213–214 ꢁC52]; 1H NMR d
(270 MHz, CDCl3) 2.63 (3H, s), 3.69 (2H, s), 5.43 (1H,
s), 6.89 (1H, dd, J = 8.3, 2.4 Hz), 7.05 (1H, d,
J = 2.0 Hz), 7.67–7.72 (2H, m), 7.95–7.986 (1H, m),
8.08 (1H, d, J = 0.7 Hz); HPLC tR = 1.70 min (>95%)
90% MeCN in H2O; LC/MS (APꢁ) m/z 222.91
(MꢁH)ꢁ; HRMS (ES+) m/z Calcd for C15H13O2
225.0910, found (M+H)+ 225.0921.
1
89–92 ꢁC; H NMR d (270 MHz, CDCl3) 2.27 (3H, s),
2.66 (3H, s), 3.95 (3H, s), 7.02 (1H, d, J = 8.7 Hz),
7.19–7.25 (4H, m), 7.44 (1H, dd, J = 8.5, 2.5 Hz), 7.73
(1H, d, J = 8.5 Hz); HPLC tR = 2.20 min (>99%) 90%
MeCN in H2O; LC/MS (ES+) m/z 263.45 (M+Na)+.
4.4.4.27. 3-Ethyl-40-methoxy-biphenyl (29). Prepared
according to the General Procedure 1, heating for
10 min. The product was purified by flash chromatogra-
phy (20 g, Flashmaster) using hexane to 20% EtOAc in
hexane followed by recrystallization from DCM/hexane
4.4.4.23. 1-(40-Hydroxy-2-methyl-biphenyl-4-yl)-etha-
none (25). Prepared according to the General Procedure
3 from 1-(40-methoxy-2-methyl-biphenyl-4-yl)-ethanone
24 to give the title compound as a pale yellow oil (yield
81%); 1H NMR d (400 MHz, CD3OD) 2.25 (3H, s), 2.63
(3H, s), 6.98 (1H, d, J = 8.6 Hz), 7.19–7.27 (4H, m), 7.45
(1H, dd, J = 8.6, 2.2 Hz), 7.77 (1H, d, J = 2.3 Hz); 13C
NMR d (100 MHz, CD3OD) 20.6, 27.0, 118.7, 120.7,
127.0, 128.5, 130.8, 131.4, 132.5, 134.3, 136.5, 138.4,
141.9, 162.2, 206.4; HPLC tR = 2.75 min (>99%) 90%
MeCN in H2O; LC/MS (APꢁ) m/z 224.99 (MꢁH)ꢁ;
HRMS (ES+) m/z Calcd for C15H15O2 227.1067, found
(M+H)+ 227.1056.
1
(yield 75%); H NMR d (270 MHz, CDCl3) 1.36 (3H, t,
J = 7.7 Hz), 2.78 (2H, q, J = 7.7 Hz), 3.89 (3H, s), 7.04
(2H, d, J = 8.9 Hz), 7.23 (1H, d, J = 5.1 Hz), 7.38–7.47
(3H, m), 7.60 (2H, d, J = 8.9 Hz); HPLC tR = 2.35 min
(>97%) 90% MeCN in H2O.
4.4.4.28. 1-(3-Ethyl-40-methoxy-biphenyl-4-yl)-etha-
none (30). To a stirred solution of 3-ethyl-40-methoxy-
biphenyl 29 (0.16 g, 0.75 mmol) in 1,2-dichloroethane
(4 mL) was added Ac2O (0.2 mL) and the solution was
cooled in an ice/acetone bath. To this was then added
AlCl3 (0.48 g) and the reaction was allowed to warm
to rt with stirring over 24 h. The reaction was quenched
with HCl (2 M, aq) and the organics extracted into
DCM. This mixture containing the title compound
and 1-(30-ethyl-4-methoxy-biphenyl-3-yl)-ethanone was
used for the demethylation step.
4.4.4.24. 2-Methoxyfluorene (26). This compound is
described in the literature.50 To a stirred solution of 2-
hydroxyfluorene (0.100 g, 0.55 mmol) in DMF
(1.5 mL) was added K2CO3 (0.23 g, 1.65 mmol) fol-

G. M. Allan et al. / Bioorg. Med. Chem. 16 (2008) 4438–4456
4451
4.4.4.29. 1-(3-Ethyl-40-hydroxy-biphenyl-4-yl)-etha-
none (31). Prepared according to the General Procedure
3 from a mixture containing 1-(3-ethyl-40-methoxy-
biphenyl-4-yl)-ethanone 30 and 1-(30-ethyl-4-methoxy-
biphenyl-3-yl)-ethanone (yield over two steps 20%): mp
mp 137–138 ꢁC; 1H NMR d (270 MHz, DMSO-d6)
1.24 (6H, s), 3.29 (2H, s), 7.69 (2H, d, J = 8.7 Hz),
7.88 (2H, d, J = 8.7 Hz), 7.96 (1H, s); HPLC
tR = 2.87 min (>93%) 70% MeCN in H2O; LC/MS
(APCI) m/z 283.15, 285.10 (MꢁH)ꢁ.
1
99–102 ꢁC; H NMR d (270 MHz, CDCl3) 1.25 (3H, t,
J = 7.4 Hz), 2.62 (3H, s), 2.97 (2H, q, J = 7.4 Hz), 6.94
(2H, d, J = 8.7 Hz), 7.38–7.45 (2H, m), 7.51 (2H, d,
J = 8.6 Hz), 7.73 (1H, d, J = 7.7 Hz); HPLC
tR = 1.80 min (>95%) 90% MeCN in H2O; LC/MS
(ESꢁ) m/z 239.03 (MꢁH)ꢁ; HRMS (ES+) m/z Calcd
for C16H17O2 241.1223, found (M+H)+ 241.1228.
4.4.4.34. 4-(30-Ethyl-40-methoxy-biphenyl)-4-oxo-buta-
noic acid (36). Prepared from 3-ethyl-4-meth-
oxyphenylboronic acid 5 and 4-(4-bromophenyl)-4-
oxo-butanoic acid 33 according to the General Proce-
dure 2 but purified by flash chromatography using gra-
dient elution of DCM to 10% MeOH in DCM, followed
by recrystallization from MeOH/H2O to give the title
compound as a pale pink powder (yield 64%): mp 91–
4.4.4.30. 2,3-Dihydro-5-phenylinden-1-one (32). Prepa-
ration and spectroscopic data as described by Zhuang
et al.36 HPLC tR = 2.25 min (>99%) 90% MeCN in
H2O.
1
94 ꢁC; H NMR d (270 MHz, DMSO-d6) 1.19 (3H, t,
J = 7.4 Hz), 2.60–2.68 (4H, m), 3.27–3.30 (2H, m), 3.37
(1H, br s), 3.86 (3H, s), 7.08 (1H, d, J = 8.6 Hz), 7.57
(1H, d, J = 2.3 Hz), 7.60 (1H, dd, J = 8.2, 2.3 Hz), 7.80
(2H, d, J = 8.6 Hz), 8.04 (2H, d, J = 8.6 Hz); 13C
NMR d (100 MHz, DMSO-d6) 14.8, 23.4, 28.4, 33.5,
55.9, 111.6, 126.2, 126.7, 128.0, 129.0, 131.3, 132.7,
134.9, 145.0. 157.9, 174.4, 198.4; HPLC tR = 2.75 min
(>96%) 80% MeCN in H2O; LC/MS (APCI) m/z
311.24 (MꢁH)ꢁ; HRMS (FAB+) m/z Calcd for
C19H20O4 312.1361, found (M+) 312.1353.
4.4.4.31. 4-(4-Bromophenyl)-4-oxo-butyric acid (33).
Preparation and spectroscopic data as described by Son-
patki et al.41 mp 148–149 ꢁC [lit. 148–149 ꢁC53].
4.4.4.32. 4-(4-Bromo-2-methylphenyl)-4-oxo-butyric
acid (34). To a stirred mixture of succinic anhydride
(0.50 g, 5.0 mmol) in 3-bromotoluene (3.74 mL,
30.85 mmol), cooled to ꢁ5 ꢁC (ice/acetone bath) was
added in one portion AlCl3 (1.33 g, 10 mmol). The reac-
tion temperature was maintained at ꢁ5 ꢁC for 4 h before
being slowly allowed to warm to rt overnight. The mix-
ture was poured into cooled (ice bath) stirred aqueous
HCl (15 mL, 18%) and stirring was continued for a fur-
ther 30 min while the solution was allowed to warm to
rt. No precipitate formed, therefore DCM (10 mL) was
added and the organic layer was separated and concen-
trated under reduced pressure. To this was added hex-
ane (5 mL) followed by a small amount of DCM (to
mix the layers). The white needles obtained were shown
by NMR to contain a small amount of the ortho prod-
uct, therefore were recrystallized again from DCM/hex-
4.4.4.35. 4-(30-Ethyl-40-methoxy-3-methyl-biphenyl-4-
yl)-4-oxo-butyric acid (37). Prepared from 3-ethyl-4-
methoxyphenylboronic acid 5 and 4-(4-bromo-2-methyl-
phenyl)-4-oxo-butyric acid 34 according to the General
Procedure 2 with purification as for 36 to give the title
compound as white solid (yield 58%): mp >130 ꢁC
(dec); 1H NMR d (270 MHz, CDCl3) 1.23 (3H, t,
J = 7.4 Hz), 2.58 (3H, s), 2.69 (2H, q, J = 7.4 Hz),
2.78–2.83 (2H, m), 3.26–3.31 (2H, m), 3.87 (3H, s),
6.91 (1H, d, J = 8.2 Hz), 7.41–7.47 (4H, m), 7.81 (1H,
d, J = 7.9 Hz); HPLC tR = 2.23 min (>99%) 50% MeCN
in H2O; LRMS (FAB+) m/z 327.1 (M+H)+; HRMS
(FAB+) m/z Calcd for C20H23O4 327.1596, found
(M+H)+ 327.1585.
1
ane (yield 63%); H NMR d (270 MHz, CDCl3) 2.46
(3H, s), 2.75–2.80 (2H, m), 3.14–3.19 (2H, m), 7.39–
7.42 (2H, m), 7.55–7.59 (1H, m); HPLC tR = 1.37 min
(>99%) 80% MeCN in H2O; LRMS (FAB+) m/z
270.9, 272.9 (M+H)+; HRMS (FAB+) m/z Calcd for
C11H12O3 79Br 270.9970, found (M+H)+ 270.9967,
Calcd for C11H12O3 81Br 272.9949, found (M+H)+
272.9949.
4.4.4.36. 4-(30-Ethyl-40-methoxy-biphenyl-4-yl)-2,2-
dimethyl-4-oxo-butyric acid (38). Prepared from 3-ethyl-
4-methoxyphenyl boronic acid 5 and 4-(4-bromophe-
nyl)-2, 2-dimethyl-4-oxo-butyric acid 35 according to
the General Procedure 3. Recrystallization from
DCM/hexane gave colorless cubes (yield 60%); 1H
NMR d (270 MHz, CDCl3) 1.29 (3H, t, J = 7.4 Hz),
1.37 (6H, s), 2.69 (2H, q, J = 7.4 Hz), 3.33 (2H, s),
3.87 (3H, s), 6.92 (1H, d, J = 8.4 Hz), 7.42–7.46 (2H,
m), 7.63 (2H, d, J = 8.4 Hz), 7.98 (2H, d, J = 8.4 Hz);
HPLC tR = 2.68 min (>99%) 90% MeCN in H2O; LC/
MS (APCI) m/z 339.17 (MꢁH+).
4.4.4.37. 5-(30-Ethyl-40-methoxy-biphenyl-4-yl)-3,3-
dimethyl-4-oxo-3H-furan-2-one (39). From attempted
amide coupling: to a stirred solution of 4-(30-ethyl-40-
methoxy-biphenyl-4-yl)-2,2-dimethyl-4-oxo-butyric acid
38 (0.100 g, 0.3 mmol) in dry DCM (15 mL) was added
DMAP (catalytic), EDCI (0.191 g, 1 mmol) and NEt3
(0.06 mL) and the reaction was stirred at rt for 20 min
before addition of 3-(2-aminoethyl) pyridine (0.06 mL).
The solution was stirred at rt for 24 h before the solution
4.4.4.33. 4-(4-Bromophenyl)-2,2-dimethyl-4-oxo-buty-
ric acid (35). To a stirred suspension of 2,2-dim-
ethylsuccinic anhydride (0.641 g, 5.0 mmol) in
bromobenzene (3.3 mL), cooled to ꢁ10 ꢁC (ice/acetone
bath) was added AlCl3 (1.34 g, 10 mmol) and the reac-
tion was allowed to warm slowly to rt with stirring over-
night. The resulting brown solution was poured into
cooled (ice bath) aqueous HCl (10 mL, 18%) and stirred
for a further 30 min while the solution was allowed to
warm to rt. No precipitate formed therefore DCM
(10 mL) was added and the organic layer was separated
and concentrated under reduced pressure to give a solu-
tion of the product in PhBr. To this was added hexane
followed by a small amount of DCM and the resulting
white needles were collected by filtration (yield 51%):

4452
G. M. Allan et al. / Bioorg. Med. Chem. 16 (2008) 4438–4456
was washed with satd aq bicarb. and the organic layer
was separated and concentrated under reduced pressure.
Flash chromatography (20g column, Flashmaster II)
using a gradient elution of DCM to 5% MeOH in
DCM yielded the title compound as the first fraction
(yield 0.026g, 27%); 1H NMR d (270 MHz, CDCl3)
1.23 (3H, t, J = 7.5 Hz), 1.41 (6H, s), 2.69 (2H, q,
J = 7.6 Hz), 3.87 (3H, s), 5.81 (1H, s), 6.91 (1H, d,
J = 6.9 Hz), 7.39–7.44 (2H, m), 7.55–7.65 (4H, m);
HPLC tR = 2.91 min (>99%) 90% MeCN in H2O; LC/
MS (APCI) m/z 323.29 (M+H)+.
8.45–8.48 (2H, m); HPLC tR = 2.33 min (>95%) 90%
MeCN in H2O; LC/MS (APCI) m/z 417.30 (M+H)+.
4.4.4.41. 4-(30-Ethyl-40-methoxy-biphenyl)-4-oxo-N-
(2-methoxyethyl)-butyramide (43). Prepared from 4-(30-
ethyl-40-methoxy-biphenyl)-4-oxo-butanoic acid 36
according to the General Procedure 4, using 2-meth-
oxyethanamine (yield 25%); 1H NMR d (270 MHz,
CDCl3) 1.23 (3H, t, J = 7.5 Hz), 2.61–2.73 (4H, m),
3.30–3.56 (9H, m), 3.86 (3H, s), 6.10 (1H, br s), 6.91
(1H, d, J = 8.7 Hz), 7.42–7.46 (2H, m), 7.63 (2H, d,
J = 8.7 Hz), 8.01 (2H, d, J = 8.4 Hz); HPLC
tR = 2.34 min (>99%) 90% MeCN in H2O; LC/MS
(APCI) m/z 370.30 (M+H)+.
From reaction of 4-(30-ethyl-40-methoxy-biphenyl-4-yl)-
2,2-dimethyl-4-oxo-butyric acid 38 with acetyl chloride:
To a stirred solution of 4-(30-ethyl-40-methoxy-biphenyl-
4-yl)-2,2-dimethyl-4-oxo-butyric acid 38 (0.055 g,
0.16 mmol) in dry DCM (5 mL) was added acetyl chlo-
ride (13 lL) and NEt3 (30 lL) and the reaction was stir-
red at rt for 48 h. To this was added DCM (5 mL) and
water (10 mL) and the organic layer was separated and
concentrated under reduced pressure. Purification by
flash chromatography (10 g column, Flashmaster II)
using an elution gradient of hexane to 10% DCM in hex-
4.4.4.42. 4-(30-Ethyl-40-methoxy-3-methyl-biphenyl)-4-
oxo-N-pyridin-3-ylmethyl-butyramide (44). Prepared
from 4-(30-ethyl-40-methoxy-3-methyl-biphenyl-4-yl)-4-
oxo-butyric acid 37 according to the General Procedure
4, using 3-aminomethyl pyridine (yield 87%); 1H NMR d
(270 MHz, CDCl3) 1.22 (3H, t, J = 7.4 Hz), 2.53 (3H, s),
2.60–2.72 (4H, m), 3.29 (2H, t, J = 6.4 Hz), 3.84 (3H, s),
4.42 (2H, d, J = 5.9 Hz), 6.88 (1H, d, J = 9.2 Hz), 6.93–
6.97 (1H, m), 7.18–7.23 (1H, m), 7.37–7.43 (4H, m),
7.61–7.66 (1H, m), 7.78 (1H, d, J = 8.9 Hz), 8.43–8.45
(1H, m), 8.49 (1H, d, J = 1.7 Hz); HPLC tR = 2.49 min
(>98%) 80% MeCN in H2O; LRMS (FAB+) m/z 417.1
(M+H)+; HRMS (FAB+) m/z Calcd for C26H29N2O3
417.2178, found (M+H)+ 417.2175.
1
ane yielded 0.029 g of product (56%); H NMR and Rf
as above.
4.4.4.38. 4-(30-Ethyl-40-methoxy-biphenyl)-4-oxo-N-
pyridin-3-ylmethyl-butyramide (40). Prepared from 4-
(30-ethyl-40-methoxy-biphenyl)-4-oxo-butanoic acid 36
according to the General Procedure 4, using 3-amino-
methyl pyridine (yield 31%); 1H NMR d (270 MHz,
CD3OD) 1.21 (3H, t, J = 7.5 Hz), 2.65–2.73 (4H, m),
3.41–3.46 (2H, m), 3.87 (3H, s), 4.62 (2H, s), 7.02 (1H,
d, J = 8.7 Hz), 7.45–7.55 (2H, m), 7.72 (2H, d,
J = 8.7 Hz), 8.04–8.12 (3H, m), 8.64 (1H, d,
J = 8.2 Hz), 8.76 (1H, d, J = 5.7 Hz), 8.89 (1H, s);
HPLC tR = 2.29 min (>99%) 90% MeCN in H2O; LC/
MS (APCI) m/z 403.25.
4.4.4.43. 4-(30-Ethyl-40-methoxy-3-methyl-biphenyl)-4-
oxo-N-pyridin-3-ylethyl-butyramide (45). Prepared from
4-(30-ethyl-40-methoxy-3-methyl-biphenyl-4-yl)-4-oxo-bu-
tyric acid 37 according to the General Procedure 4, using
2-(pyridin-3-yl)ethanamine (yield 80%); 1H NMR d
(270 MHz, CDCl3) 1.21 (3H, t, J = 7.4 Hz), 2.53–2.57
(5H, m), 2.67 (2H, q, J = 7.4 Hz), 2.77–2.83 (2H, m),
3.23–3.28 (2H, m), 3.49 (2H, dd, J = 13.1, 6.9 Hz), 3.83
(3H, s), 6.49–6.53 (1H, m), 6.87 (1H, d, J = 9.2 Hz),
7.14–7.20 (1H, m), 7.38–7.44 (4H, m), 7.50–7.54 (1H,
m), 7.79 (1H, d, J = 8.4 Hz), 8.38–8.43 (2H, m); HPLC
tR = 2.52 min (>98%) 80% MeCN in H2O; LRMS
(FAB)+ m/z 431.2 (M+H)+; HRMS (FAB+) m/z Calcd
for C27H31N2O3 431.2335, found (M+H)+ 431.2337.
4.4.4.39. 4-(30-Ethyl-40-methoxy-biphenyl)-4-oxo-N-
pyridin-2-ylmethyl-butyramide (41). Prepared from 4-
(30-ethyl-40-methoxy-biphenyl)-4-oxo-butanoic acid 36
according to the General Procedure 4, using 2-amino-
methylpyridine (yield 31%); 1H NMR d (270 MHz,
CDCl3) 1.23 (3H, t, J = 7.5 Hz), 2.65–2.76 (4H, m),
3.39–3.45 (2H, m), 3.87 (3H, s), 4.57 and 4.59 (2H, 2·
s), 6.90–6.93 (2H, m), 7.16–7.21 (1H, m), 7.25–7.27
(1H, m), 7.42–7.47 (2H, m), 7.62–7.68 (3H, m), 8.03
(2H, d, J = 8.4 Hz), 8.53 (1H, d, J = 4.5 Hz); HPLC
tR = 2.34 min (>96%) 90% MeCN in H2O; LC/MS
(APCI) m/z 403.25 (M+H)+.
4.4.4.44. 4-(30-Ethyl-40-methoxy-biphenyl)-2,2-dimethyl-
4-oxo-N-pyridin-3-ylmethyl-butyramide (46). To a stirred
solution of 5-(30-ethyl-40-methoxy-biphenyl-4-yl)-3,3-di-
methyl-4-oxo-3H-furan-2-one 39 (0.0265 g, 0.08 mmol)
in dry DCM (5 mL) was added 3-aminomethyl pyridine
(0.01 mL) and the mixture was heated to reflux for 22 h
before being cooled and concentrated under reduced
pressure. The product was purified by flash chromatog-
raphy using an elution gradient of DCM to 10% MeOH
4.4.4.40. 4-(30-Ethyl-40-methoxy-biphenyl)-4-oxo-N-
pyridin-3-ylethyl-butyramide (42). Prepared from 4-(30-
ethyl-40-methoxy-biphenyl)-4-oxo-butanoic acid 36
according to the General Procedure 4, using 2-(pyri-
1
in DCM (yield 54%); H NMR d (270 MHz, CDCl3)
1.20–1.27 (6H, m), 1.36 (3H, s), 2.35 (2H, s), 2.69 (2H,
q, J = 7.4 Hz), 3.86 (3H, s), 3.97 (1H, d, J = 15.1 Hz),
4.68 (1H, d, J = 15.1 Hz), 4.97 (1H, br s), 6.91 (1H, d,
J = 9.2 Hz), 7.06–7.11 (1H, m), 7.38–7.41 (4H, m),
7.53–7.61 (3H, m), 8.12–8.15 (2H, m); HPLC
tR = 2.61 min (>99%) 80% MeCN in H2O; LC/MS
(APCI) m/z 431.42 (M+H)+; HRMS (FAB+) m/z Calcd
for C27H31N2O3 431.2335, found (M+H)+ 431.2336.
din-3-yl)ethanamine (yield 30%); 1H NMR
d
(270 MHz, CDCl3) 1.23 (3H, t, J = 7.5 Hz), 2.59 (2H,
t, J = 6.4 Hz), 2.69 (2H, q, J = 7.5 Hz), 2.80–2.86 (2H,
m), 3.36 (2H, t, J = 6.4 Hz), 3.48–3.56 (2H, m), 3.87
(3H, s), 5.90 (1H, br s), 6.92 (1H, d, J = 8.7 Hz), 7.16–
7.25 (1H, m), 7.42–7.47 (2H, m), 7.52–7.56 (1H, m),
7.65 (2H, d, J = 8.4 Hz), 8.01 (2H, d, J = 8.7 Hz),

G. M. Allan et al. / Bioorg. Med. Chem. 16 (2008) 4438–4456
4453
4.4.4.45. 4-(30-Ethyl-40-methoxy-biphenyl)-2,2-dimethyl-
4-oxo-N-pyridin-3-ylethyl-butyramide (47). To a stirred
solution of 5-(30-ethyl-40-methoxy-biphenyl-4-yl)-3,3-di-
methyl-4-oxo-3H-furan-2-one 39 (0.029 g, 0.09 mmol)
in dry DCM (5 mL) was added 2-(pyridin-3-yl)ethan-
amine (0.01 mL) and the mixture was heated to reflux
for 46 h before being cooled and concentrated under re-
duced pressure. The product was purified by flash chro-
matography using an elution gradient of DCM to 10%
ethyl-40-methoxy-biphenyl)-4-oxo-N-(2-methoxyethyl)-
butyramide 32 according to the General Procedure 3
(yield 41%): mp >110 ꢁC (dec); H NMR d (270 MHz,
CD3OD) 1.22 (3H, t, J = 7.5 Hz), 2.61–2.71 (4H, m),
3.29–3.38 (4H, m), 3.59–3.63 (2H, m), 6.84 (1H, d,
J = 8.4 Hz), 7.35 (1H, dd, J = 8.2, 2.5 Hz), 7.42 (1H, d,
J = 2.2 Hz), 7.68 (2H, d, J = 8.4 Hz), 8.02 (1H, d,
J = 8.4 Hz); HPLC tR = 1.76 min (>93%) 90% MeCN
in H2O; LC/MS (APCI) m/z 342.13 (M+H)+; HRMS
(FAB+) m/z Calcd for C20H24NO4 342.1700, found
(M+H)+ 342.1700.
1
1
MeOH in DCM (yield 100%); H NMR d (270 MHz,
CDCl3) 1.19–1.24 (6H, m), 1.31 (3H, s), 2.30 (2H, s),
2.68 (2H, q, J = 7.4 Hz), 2.87–3.08 (3H, m), 3.54–3.65
(1H, m), 3.85 (3H, s), 6.89 (1H, d, J = 9.2 Hz), 7.08–
7.13 (1H, m), 7.36–7.42 (4H, m), 7.48–7.55 (3H, m),
8.15 (2H, br s); HPLC tR = 3.11 min (>96%) 90%
MeCN in H2O; LRMS (FAB+) m/z 445.2 (M+H)+;
HRMS (FAB+) m/z Calcd for C28H33N2O3 445.2491,
found (M+H)+ 445.2490.
4.4.4.50. 4-(30-Ethyl-40-hydroxy-3-methyl-biphenyl)-4-
oxo-N-pyridin-3-ylmethyl-butyramide (52). Prepared
from 4-(30-ethyl-40-methoxy-3-methyl-biphenyl)-4-oxo-
N-pyridin-3-ylmethyl-butyramide 44 according to the
1
General Procedure 3 (yield 93%): mp 158–160 ꢁC; H
NMR d (270 MHz, CD3OD) 1.23 (3H, t, J = 7.5 Hz),
2.50 (3H, s), 2.63–2.71 (4H, m), 3.28–3.34 (2H, m),
4.43 (2H, s), 6.82 (1H, d, J = 8.4 Hz), 7.30–7.49 (5H,
m), 7.81–7.87 (2H, m), 8.41 (2H, d, J = 4.2 Hz), 8.52
(1H, s); 13C NMR d (100 MHz, DMSO-d6) 14.8, 21.6,
23.4, 29.9, 36.4, 55.4, 115.8, 118.4, 123.6, 123.9, 125.7,
128.1, 129.4, 129.9, 130.1, 131.0, 135.4, 135.7, 138.4,
143.5, 148.5, 129.1, 156.2, 172.1, 202.7; HPLC
tR = 1.91 min (>97%) 90% MeCN in H2O; FAB-LRMS
(FAB+) m/z 403.0 (M+H)+; HRMS (FAB+) m/z
Calcd for C25H27N2O3 403.20226, found (M+H)+
403.2026.
4.4.4.46. 4-(30-Ethyl-40-hydroxy-biphenyl)-4-oxo-N-pyri-
din-3-ylmethyl-butyramide (48). Prepared from 4-(30-ethyl-
40-methoxy-biphenyl)-4-oxo-N-pyridin-3-ylmethyl-butyra-
mide 27 according to the General Procedure 3 (yield 41%):
1
mp >150 ꢁC (dec); H NMR d (270 MHz, CD3OD) 1.23
(3H, t, J = 7.5 Hz), 2.65–2.72 (4H, m), 3.37–3.42 (2H,
m), 4.44 (2H, s), 6.83 (1H, d, J = 8.2 Hz), 7.35–7.43 (3H,
m), 7.69 (2H, d, J = 8.7 Hz), 7.82 (1H, d, J = 7.4 Hz),
8.03 (2H, d, J = 8.4 Hz), 8.41–8.44 (1H, m), 8.52 (1H, s);
HPLC tR = 1.83 min (>96%) 90% MeCN in H2O; LC/
MS (APCI) m/z 389.20 (M+H)+; HRMS (FAB+) m/z
Calcd for C24H25N2O3 389.1865, found (M+H)+ 389.1867.
4.4.4.51. 4-(30-Ethyl-40-hydroxy-3-methyl-biphenyl)-4-
oxo-N-pyridin-3-ylethyl-butyramide (53). Prepared from
4-(30-ethyl-40-methoxy-3-methyl-biphenyl)-4-oxo-N-
pyridin-3-ylethyl-butyramide 45 according to the Gen-
eral Procedure 3 (yield 75%): mp 151–154 ꢁC; 1H
NMR d (400 MHz, CD3OD) 1.27 (3H, t, J = 7.5 Hz),
2.56–2.57 (5H, m), 2.71 (2H, q, J = 7.5 Hz), 2.88 (2H,
t, J = 7.0 Hz), 3.48 (2H, t, J = 7.0 Hz), 6.84 (1H, d,
J = 8.3 Hz), 7.33–7.53 (5H, m), 7.90 (1H, dt, J = 7.8,
1.9 Hz), 7.87 (1H, d, J = 8.0 Hz), 8.41 (1H, dd, J = 4.8,
4.4.4.47. 4-(30-Ethyl-40-hydroxy-biphenyl)-4-oxo-N-pyri-
din-2-ylmethyl-butyramide (49). Prepared from 4-(30-ethyl-
40-methoxy-biphenyl)-4-oxo-N-pyridin-2-ylmethyl-butyra-
mide 28 according to the General Procedure 3 (yield 5%):
1
mp 144–146 ꢁC; H NMR d (270 MHz, CD3OD) 1.23
(3H, t, J = 7.5 Hz), 2.64–2.75 (4H, m), 3.40–3.46 (2H,
m), 4.51 (2H, s), 6.84 (1H, d, J = 8.2 Hz), 7.28–7.50 (4H,
m), 7.69 (2H, d, J = 8.7 Hz), 7.79–7.86 (1H, m), 8.05
(2H, d, J = 8.7 Hz), 8.47 (1H, d, J = 4.7 Hz); HPLC
tR = 1.89 min (>90%) 90% MeCN in H2O; LC/MS (APCI)
m/z 389.14 (M+H)+; HRMS (FAB+) m/z Calcd for
C24H25N2O3 389.1865, found (M+H)+ 389.1871.
1.6 Hz), 8.48 (1H, d, J = 1.6 Hz); 13C NMR
d
(100 MHz, CD3OD) 13.5, 20.6, 23.1, 29.5, 32.2, 40.0,
110.0, 115.5, 123.1, 123.8, 125.1, 127.4, 129.1, 129.6,
129.8, 131.3, 134.5, 135.8, 137.5, 138.7, 144.7, 146.6,
149.1, 157.1, 173.80; HPLC tR = 1.91 min (>99%) 90%
MeCN in H2O; LRMS (FAB+) m/z 417.1 (M+H)+;
HRMS (FAB+) m/z Calcd for C26H29N2O3 417.2178,
found (M+H)+ 417.2179.
4.4.4.48. 4-(30-Ethyl-40-hydroxy-biphenyl)-4-oxo-N-
pyridin-3-ylethyl-butyramide (50). Prepared from 4-(30-
ethyl-40-methoxy-biphenyl)-4-oxo-N-pyridin-3-ylethyl-
butyramide29 according to the General Procedure 3
(yield 72%): mp 103–105 ꢁC; 1H NMR d (270 MHz,
CD3OD) 1.22 (3H, t, J = 7.5 Hz), 2.55 (2H, t,
J = 6.2 Hz), 2.67 (2H, q, J = 7.5 Hz), 3.08 (2H, t,
J = 6.2 Hz), 3.27–3.32 (2H, m), 3.55–3.60 (2H, m), 6.84
(1H, d, J = 8.2 Hz), 7.35 (1H, dd, J = 8.4,2.2 Hz), 7.41
(1H, d, J = 2.2 Hz), 7.67 (2H, d, J = 8.4 Hz), 7.98–8.04
(3H, m), 8.60 (1H, d, J = 8.2 Hz), 8.73 (1H, d,
J = 5.7 Hz), 8.88 (1H, s); HPLC tR = 1.85 min (>99%)
90% MeCN in H2O; LC/MS (APCI) m/z 403.19
(M+H)+; HRMS (FAB+) m/z Calcd for C25H27N2O3
403.2021, found (M+H)+ 403.2026.
4.4.4.52. 4-(30-Ethyl-40-hydroxy-biphenyl)-2,2-dimethyl-
4-oxo-N-pyridin-3-ylmethyl-butyramide (54). Prepared
from 4-(30-ethyl-40-methoxy-biphenyl)-2,2-dimethyl-4-
oxo-N-pyridin-3-ylmethyl-butyramide 46 according
to the General Procedure 3 (yield 72%); 1H NMR
d (400 MHz, CD3OD) 1.26 (3H, t, J = 7.4 Hz), 1.30
(3H, s), 1.41 (3H, s), 2.36–2.45 (2H, m), 2.70 (2H, q,
J = 7.6 Hz), 4.32–4.42 (2H, m), 6.84 (1H, d, J = 8.2 Hz),
7.27–7.30 (2H, m), 7.35 (1H, d, J = 2.1 Hz), 7.40 (2H,
d, J = 8.7 Hz), 7.50 (2H, d, J = 8.5 Hz), 7.67 (1H, d,
J = 7.9 Hz) 8.30 (1H, s), 8.34 (1H, s); HPLC
tR = 1.98 min (>94%) 70% MeCN in H2O; LRMS
(FAB+) m/z 417.1 (M+H)+; HRMS (FAB+) m/z Calcd
for C26H29N2O3 417.2178, found (M+H)+ 417.2176.
4.4.4.49. 4-(30-Ethyl-40-hydroxy-biphenyl)-4-oxo-N-(2-
hydroxyethyl)-butyramide (51). Prepared from 4-(30-

4454
G. M. Allan et al. / Bioorg. Med. Chem. 16 (2008) 4438–4456
4.4.4.53. 4-(30-Ethyl-40-hydroxy-biphenyl)-2,2-dimethyl-
acetic acid 57 (0.070 g, 0.21 mmol) in DCM (12 mL)
was added EDCI (0.123 g, 0.64 mmol) followed by
DMAP (10 mg, cat. amount) and Et3N (0.070 mL)
and the mixture was stirred at rt for 20–30 min. To this
was then added 3-aminomethyl pyridine (0.046 g,
0.43 mmol) and the resultant mixture was stirred for
25 h. The reaction was quenched with satd Na2CO3,
the organics extracted into DCM (2· 20 mL) and the ex-
tracts were combined, dried (MgSO4), and concentrated.
The crude product was purified by flash chromatogra-
phy (DCM/MeOH, gradient elution) to give the title
compound (20 mg, 23%) as a pale yellow solid; 1H
NMR d (270 MHz, CDCl3) 1.23 (3H, t, J = 7.6 Hz),
2.59–3.20 (6H, m), 3.48 (1H, dd, J = 16.8, 8.6 Hz),
3.87 (3H, s), 4.43–4.46 (2H, m), 6.55 (1H, br t), 6.92
(1H, d, J = 8.4 Hz), 7.19–7.22 (1H, m), 7.42 (1H, s),
7.46 (1H, d, J = 2.2 Hz), 7.56–7.60 (3H, m), 7.75 (1H,
d, J = 7.6 Hz), 8.48–8.51 (2H, m); LC/MS (APCI) m/z
415 (M+H)+.
4-oxo-N-pyridin-3-ylethyl-butyramide (55). Prepared from
4-(30-ethyl-40-methoxy-biphenyl)-2,2-dimethyl-4-oxo-N-
pyridin-3-ylethyl-butyramide 47 according to the General
1
Procedure 3 (yield 52%): mp >130 ꢁC (dec); H NMR d
(270 MHz, CD3OD) 1.19–1.24 (6H, m), 1.32 (3H, s),
2.26–2.36 (2H, m), 2.66 (2H, q, J = 7.4 Hz), 2.82–2.90
(2H, m), 3.05–3.16 (1H, m), 3.42–3.53 (1H, m), 6.80
(1H, d, J = 8.2 Hz), 7.26–7.30 (2H, m), 7.35 (1H, d,
J = 2.2 Hz), 7.42 (2H, d, J = 8.4 Hz), 7.56–7.62 (3H, m),
8.28–8.32 (2H, m); 13C NMR d (100 MHz, CD3OD)
13.5, 23.1, 25.1, 25.9, 31.5, 39.8, 41.7, 52.2, 90.9, 114.8,
124.9, 126.1, 127.5, 130.9, 131.4, 137.3, 141.3, 141.4,
146.5, 149.0, 154.9, 181.5; HPLC tR = 2.02 min (>99%)
90% MeCN in H2O; LRMS (FAB+) m/z 431.2
(M+H)+; HRMS (FAB+) m/z Calcd for C27H31N2O3
431.2335, found (M+H)+ 431.2340.
4.4.4.54. [5-(3-Ethyl-4-methoxyphenyl)-1-oxo-indan-2-
yl]-acetic acid ethyl ester (56). A solution of 5-(3-ethyl-4-
methoxyphenyl)-indan-1-one 11 (0.312 g, 2.08 mmol) in
dry THF (12 mL) under an inert atmosphere was cooled
to ꢁ10 ꢁC and stirred for 15 min. To this was added
over 15 min at ꢁ10 ꢁC a solution of LDA (1.8 M solu-
tion in heptane/THF/ethyl benzene, 0.711 mL,
1.28 mmol). The mixture was cooled to ꢁ60 ꢁC and stir-
red at this temperature for 20 min before ethyl bromo-
acetate (0.155 mL, 1.40 mmol) was added drop-wise
and the mixture stirred at ꢁ60 ꢁC for 2–3 h and allowed
to warm to rt overnight. The overall reaction time was
18 h. The reaction mixture was quenched with sat.
NH4Cl and the organics extracted into DCM (3·
20 mL). These extracts were combined, dried (MgSO4),
and concentrated to obtain a pale yellow solid. The solid
was passed through a silica column (EtOAc/hexanes,
gradient elution) to obtain the title compound mixed
with the bis-alkylated product. This mixture was sub-
jected to ester hydrolysis without further purification.
4.4.4.57. 2-[5-(3-Ethyl-4-methoxyphenyl)-1-oxo-indan-
2-yl]-N-pyridin-2-ylmethyl-acetamide (59). To a suspen-
sion of [5-(3-ethyl-4-methoxyphenyl)-1-oxo-indan-2-yl]-
acetic acid 57 (0.050 g, 0.15 mmol) in DCM (10 mL)
was added EDCI (0.087 g, 0.46 mmol) followed by
DMAP (10 mg, cat. amount) and Et3N (0.050 mL)
and the mixture stirred at rt for 20–30 min. To this
was then added 2-aminomethyl pyridine (0.031 mL,
0.30 mmol) and the resultant mixture stirred for 25 h.
The reaction was quenched with sat. Na2CO3 and the
organics extracted into DCM (2· 20 mL). The extracts
were combined, dried (MgSO4), and concentrated and
the crude product was purified by chromatography
(DCM/MeOH, gradient elution) to give the title com-
1
pound (40 mg, 63%) as a pale yellow solid; H NMR d
(270 MHz, CDCl3) 1.23 (3H, t, J = 7.4 Hz), 2.59–3.20
(6H, m), 3.26 (1H, dd, J = 17.8, 7.9 Hz), 3.87 (3H, s),
4.56 (2H, d, J = 4.9 Hz), 6.92 (1H, d, J = 8.4 Hz),
7.17–7.20 (1H, m), 7.41–7.46 (3H, m), 7.55–7.66 (3H,
m), 7.76–7.79 (1H, d, J = 7.9 Hz), 8.50–8.51 (1H, m);
LC/MS (APCI) m/z 415 (M+H)+.
4.4.4.55. [5-(3-Ethyl-4-methoxyphenyl)-1-oxo-indan-2-
yl]-acetic acid (57). To a suspension of [5-(3-ethyl-4-
methoxyphenyl)-1-oxo-indan-2-yl]-acetic acid ethyl ester
56 (0.530 g, 1.56 mmol) in THF/water (1:1, 5 mL) was
added NaOH (0.124 g, 3.12 mmol) and the mixture was
stirred at rt for 2 days. Analysis by TLC showed two ma-
jor products (DCM/MeOH, 95:5, Rf = 0.02 and 0.39).
The resultant pale orange mixture was acidified to pH 2
with 2 M HCl and extracted with DCM (2· 20 mL)
and EtOAc (2· 20 mL). The combined extracts were
dried (Na2SO4) and concentrated and the crude product
was purified by chromatography (DCM/MeOH gradient
elution). The compound with Rf = 0.39 was separated
and shown to be the title compound (0.158 g, 16% over
4.4.4.58. 2-[5-(3-Ethyl-4-methoxyphenyl)-1-oxo-indan-
2-yl]-N-(5-methyl-pyrazin-2-ylmethyl)-acetamide (60). To
a stirred suspension of [5-(3-ethyl-4-methoxyphenyl)-1-
oxo-indan-2-yl]-acetic acid 57 (0.050 g, 0.15 mmol) in
DCM (10 mL) was added EDCI (0.087 g, 0.46 mmol)
followed by DMAP (10 mg, catalytic amount) and
Et3N (0.050 mL) and the mixture stirred at rt for 20–
30 min. To this was added 2-aminomethyl-5-methylpyr-
azine (0.037 g, 0.30 mmol) and the resultant mixture
stirred for 25 h. The reaction was quenched with satd
Na2CO3, the organics extracted into DCM (2· 20 mL),
and the extracts were combined, dried (MgSO4), and
concentrated. The crude product was purified by flash
chromatography (DCM/MeOH, gradient elution) to
give the title compound (28 mg, 42%) as a pale yellow
solid; 1H NMR d (270 MHz, CDCl3) 1.23 (3H, t,
J = 7.4 Hz), 2.53 (3H, s), 2.53–3.18 (5H, m), 3.44–3.50
(2H, m), 3.87 (3H, s), 4.55–4.66 (2H, m), 6.84 (1H, br
s), 6.92 (1H, d, J = 7.8 Hz), 7.37–7.45 (2H, m), 7.55–
7.59 (2H, m), 7.77 (1H, d, J = 7.9 Hz), 8.07–8.45 (2H,
m); LC/MS (APCI) m/z 430 (M+H)+.
1
two steps); H NMR d (270 MHz, CDCl3) 1.23 (3H, t,
J = 7.6 Hz), 2.63–2.73 (3H, m), 2.89–3.17 (3H, m), 3.50
(1H, dd, J = 17.3, 7.6 Hz), 3.87 (3H, s), 6.92 (1H, d,
J = 8.4 Hz), 7.42–7.45 (2H, m), 7.56–7.63 (2H, m), 7.79
(1H, d, J = 7.9 Hz); HPLC tR = 2.01 min (>92%) 80%
MeCN in H2O; LRMS (FAB+) m/z 325 (M+H)+.
4.4.4.56. 2-[5-(3-Ethyl-4-methoxyphenyl)-1-oxo-indan-
2-yl]-N-pyridin-3-ylmethyl-acetamide (58). To a suspen-
sion of [5-(3-ethyl-4-methoxyphenyl)-1-oxo-indan-2-yl]-

G. M. Allan et al. / Bioorg. Med. Chem. 16 (2008) 4438–4456
4455
3. Stanway, S.; Purohit, A.; Woo, L. W.; Wilson, R. H.;
Stanczyk, F. Z.; Dobbs, N.; Delavault, P.; Potter, B. V. L.;
Reed, M. J.; Coombes, R. C. J. Clin. Oncol. 2006, 24, 22S.
4. Stanway, S. J.; Delavault, P.; Purohit, A.; Woo, L. W.;
Thurieau, C.; Potter, B. V. L.; Reed, M. J. Oncologist
2007, 12, 370–374.
5. Stanway, S. J.; Purohit, A.; Woo, L. W.; Sufi, S.; Vigushin,
D.; Ward, R.; Wilson, R. H.; Stanczyk, F. Z.; Dobbs, N.;
Kulinskaya, E.; Elliott, M.; Potter, B. V. L.; Reed, M. J.;
Coombes, R. C. Clin. Cancer Res. 2006, 12, 1585–1592.
6. Mindnich, R.; Moller, G.; Adamski, J. Mol. Cell. Endo-
crinol. 2004, 218, 7–20.
4.4.4.59. 2-[5-(3-Ethyl-4-hydroxyphenyl)-1-oxo-indan-
2-yl]-N-pyridin-3-ylmethyl-acetamide (61). Prepared
from 2-[5-(3-ethyl-4-methoxyphenyl)-1-oxo-indan-2-
yl]-N-pyridin-3-ylmethyl-acetamide 58 according to
the General Procedure 3 (yield 31%); 1H NMR d
(270 MHz, CDCl3) 1.22 (3H, t, J = 7.4 Hz), 2.65–3.06
(6H, m), 3.38 (1H, dd, J = 17.1, 8.1 Hz), 4.44–4.47
(2H, m), 4.66 (1H, br s), 6.55 (1H, br t), 6.22 (1H, d,
J = 8.2 Hz), 7.27–7.30 (1H, m), 7.39 (1H, m), 7.52–
7.57 (3H, m), 7.74 (1H, d, J = 7.9 Hz), 8.07 (1H, s),
8.50–8.52 (2H, m); HPLC tR = 2.45 min (>96%) 50%
MeCN in H2O; LC/MS (APCI) m/z 401 (M+H)+.
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4.4.4.60. 2-[5-(3-Ethyl-4-hydroxyphenyl)-1-oxo-indan-
2-yl]-N-pyridin-2-ylmethyl-acetamide (62). Prepared
from 2-[5-(3-ethyl-4-methoxyphenyl)-1-oxo-indan-2-
yl]-N-pyridin-2-ylmethyl-acetamide 59 according to
the General Procedure 3 (yield 37%); 1H NMR d
(270 MHz, CDCl3) 1.19 (2H, t, J = 7.4 Hz), 2.51–2.63
(2H, m), 2.87 (1H, t, J = 3.9 Hz), 2.96 (2H, t,
J = 5.4 Hz), 3.01–3.06 (1H, m), 3.38 (1H, dd,
J = 17.1, 8.1 Hz), 4.51–4.53 (2H, m), 4.61 (1H, s),
6.73 (1H, d, J = 8.2 Hz), 6.93–6.94 (1H, br t), 7.12–
7.18 (1H, m), 7.23 (1H, dd, J = 8.2, 2.3 Hz), 7.32 (1H,
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J = 7.8, 1.6 Hz), 7.70 (1H, d, J = 8.6 Hz), 8.02 (1H, s),
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50% MeCN in H2O; LC/MS (APCI) m/z 401 (M+H)+.
4.4.4.61. 2-[5-(3-Ethyl-4-hydroxyphenyl)-1-oxo-indan-
2-yl]-N-(5-methyl-pyrazin-2-ylmethyl)-acetamide (63). Pre-
pared from 2-[5-(3-ethyl-4-methoxyphenyl)-1-oxo-indan-
2-yl]-N-(5-methyl-pyrazin-2-ylmethyl)-acetamide 60
according to the General Procedure 3 (yield 39%):
according to 1H NMR this compound exists as a mixture
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d (270 MHz, CDCl3) 1.27 (3H, t, J = 7.4 Hz), 2.58 (3H,
s), 2.61–2.66 (1H, m), 2.74 (2H, q, J = 7.4 Hz), 2.95–
3.06 (2H, m), 3.13–3.19 (1H, m), 3.54 (1H, dd, J = 17.1,
7.8 Hz), 3.92 (3H, s), 4.61 (2H, d, J = 5.4 Hz), 4.71 (2H,
s), 6.89 (1H, br s), 6.96 (1H, d, J = 8.1 Hz), 7.46–7.52
(2H, m), 7.60–7.64 (2H, m), 7.82 (1H, d, J = 8.1 Hz),
8.12 (1H, s), 8.39 (1H, s), 8.50 (1H, s); HPLC
tR = 2.43 min (>84%) 80% MeCN in H2O; LC/MS
(APCI) m/z 416 (M+H)+.
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Acknowledgments
This research was supported by Sterix Ltd, a member of
the Ipsen group. Alison Smith is thanked for expert
technical assistance and Andrew Smith for molecular
modeling discussions.
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