1,5-Dihydro-benzo[e][1,4]oxazepin-2(1H)-ones containing a 7-(5′-cyanopyrrol-2-yl) group as nonsteroidal progesterone receptor modulators

Article abstract of DOI:10.1016/j.bmcl.2008.08.015

A series of novel 7-(5′-cyanopyrrol-2-yl) substituted benzo[1,4]oxazepin-2-ones were prepared and tested for their progesterone receptor (PR) agonist or antagonist activity in the alkaline phosphatase assay using the human T47D breast carcinoma cell line.

Full text of DOI:10.1016/j.bmcl.2008.08.015

Bioorganic & Medicinal Chemistry Letters 18 (2008) 5015–5017
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
1,5-Dihydro-benzo[e][1,4]oxazepin-2(1H)-ones containing
a 7-(50-cyanopyrrol-2-yl) group as nonsteroidal progesterone receptor
modulators q
Jeffrey C. Kern a, Eugene A. Terefenko a, Andrew Fensome a, Ray Unwalla a, Jay Wrobel a,
Jeffrey Cohen b, Yuan Zhu b, Thomas J. Berrodin b, Matthew R. Yudt b, Richard C. Winneker b,
Zhiming Zhang b, Puwen Zhang a,
*
a Chemical and Screening Sciences, Wyeth Research, 500 Arcola Road, Collegeville, PA 19426, USA
b Women’s Health and Musculoskeletal Biology, Wyeth Research, 500 Arcola Road, Collegeville, PA 19426, USA
a r t i c l e i n f o
a b s t r a c t
A series of novel 7-(50-cyanopyrrol-2-yl) substituted benzo[1,4]oxazepin-2-ones were prepared and
tested for their progesterone receptor (PR) agonist or antagonist activity in the alkaline phosphatase
assay using the human T47D breast carcinoma cell line. Both PR agonists and antagonists were achieved
with an appropriate choice of 5-substitution. Several analogs were potent PR agonists (e.g., 12 and 13) or
PR antagonists (e.g., 18) with good selectivity over other steroid receptors.
Article history:
Received 23 June 2008
Revised 4 August 2008
Accepted 5 August 2008
Available online 9 August 2008
Ó 2008 Elsevier Ltd. All rights reserved.
Keywords:
Progesterone receptor (PR)
PR agonist
PR antagonist
Non-steroidal
The progesterone receptor (PR) is a member of the superfamily of
ligand-dependent transcription factors.1 Progesterone (1) is an
endogenous hormone which plays an important role in female
reproduction. In the clinic, steroidal PR agonists have been used
widely in contraception and postmenopausal hormone therapy, of-
ten in combination with an estrogen.2 Mifepristone (2), a steroidal
PR antagonist, demonstrated potential utility in female contracep-
tion,3 and for the treatment of various gynecological and obstetric
diseases including hormone dependent cancers and non-malignant
chronic conditions such as fibroids and endometriosis.4–7 However,
steroidal PR agonists and antagonists, albeit efficacious in their
respective indications, have side effects due to the interactions with
other steroidal receptors such as the glucocorticoid receptor (GR),
and potential effects of steroidal metabolites. In an effort to mitigate
some of these undesirable effects associated with steroidal com-
pounds, we have previously reported several series of non-steroidal
PR modulators including 6-aryl benzoxazinones and benzoxazine-
2-thiones.8–10 We found in the 6-aryl-benzoxazinone series that
replacement of the 6-phenyl moiety with a 6-(50-cyanopyrrol-2-
yl) group (e.g., 3)8 caused the functional activity of this series to
switch from PR antagonism to PR agonism in the PR alkaline phos-
phatase assay using the human T47D breast carcinoma cell line.
Intrigued by the impact of the 6-(50-cyanopyrrol-2-yl) group on
PR functional activity of the 6-aryl benzoxazinone series, we
decided to expand the six-membered ring benzoxazinone core
and examine the SAR of 7-(50-cyanopyrrol-2-yl)benzo[1,4]oxaze-
pin-2-ones (4–24)11 at the PR. Herein, we report the synthesis
and the SAR of 7-(50-cyanopyrrol-2-yl)benzo[1,4]oxazepin-2-ones
as PR modulators.
Me
N
O
Me
Me
Me
Me
OH
Me
Me
H
H
O
O
Progesterone, 1
Mifepristone, 2
R2
R1
NC
NC
7
O
N
N
5
O
R3
1
N
q
Presented in preliminary form at 230th ACS National Meeting, San Francisco, CA,
O
N
H
O
United States, September 10–14, 2006.
* Corresponding author. Tel.: +1 484 865 3856; fax: +1 484 865 9398.
E-mail address: ZhangP@wyeth.com (P. Zhang).
R
3
4-24
0960-894X/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmcl.2008.08.015

5016
J. C. Kern et al. / Bioorg. Med. Chem. Lett. 18 (2008) 5015–5017
R2
O
R2
O
R1 R2
OH
NH2
R1
R1
O
Br
Br
Br
a, b
c, d
e
N
Boc
OH
NH2
N
H
27
N
O
O
H
25
26
28
f
R2
O
R2
O
R2
O
R1
R1
R1
h
g
NC
NC
NC
N
Me
N
H
N
Boc
N
N
N
O
O
O
H
H
R
4-24
30
29
Scheme 1. Synthesis of 7-(50-cyanopyrrol-2-yl)benzo[1,4]oxazepin-2-ones. Reagents and conditions: (a) R1Li, THF, ꢀ78 °C to 0 °C, N2, 20–70%; (b) R2Li, THF, 0 °C, N2; or LAH,
THF, ꢀ78 °C, N2; 40–80%; (c) ClCH2COCl, Et3N, THF, 0 °C to rt, 40–70%; (d) NaH, THF, 0 °C, N2, 50–85%; (e) N-Boc-pyrrole-2-boronic acid, Pd(PPh3)4, Na2CO3, glyme/H2O, 80 °C,
N2, 50–80%; (f) CSI, THF, ꢀ78 °C, DMF, N2, 30–70%; (g) neat, 180 °C, 60–90%; (h) MeI, K2CO3, DMF, rt, N2, 40–80%.
Target compounds 4–24 (Scheme 1) were prepared as follows:
addition of an appropriate organolithium reagent to anthranilic
Table 1
acid 25 resulted in the corresponding ketone, which was treated
PR-induced alkaline phosphatase activity and competition binding of 7-(50-cyano-
with the second organolithium species or reduced with lithium
pyrrol-2-yl)benzoxazepinones
aluminum hydride to give carbinols 26. Acetylation of carbinols
R1
O
R1
O
R2
R2
26 with chloroacetyl chloride followed by a ring closure furnished
the core structure benzoxazepinones 27. The Boc-pyrrol-2-yl moi-
ety was installed at the 7-position via a Suzuki coupling protocol
using a palladium catalyst to afford 28.
NC
NC
N
N
R3
R3
N
N
Cyanation of pyrrole at the 50-position to yield 29 was achieved
by treatment of 28 with chlorosulfonyl isocyanate (CSI), followed
by addition of DMF at low temperature. Removal of the BOC group
by heating 29 gave 30, which was alkylated with methyl iodide to
deliver the target compounds 4–24.
O
O
H
4-21
22-24
Compound R1
R2
R3
EC50
IC50
Binding
IC50
(nM)
a
b
c
(nM)
(nM)
We have previously reported a number of cyanopyrrole-con-
taining non-steroidal PR modulators such as 6-aryl benzoxazin-
2-ones, 6-aryl benzimidazolones, and 5-aryl oxindoles.8,12,13
Among the analogs reported in the 6-aryl-benzoxazinone series,
replacement of the 6-phenyl moiety with a 6-(50-cyanopyrrol-2-
yl) group caused the functional activity of this series to switch
from PR antagonism to PR agonism.8 Interestingly, in the benz-
imidazolone series, the cyanopyrrole moiety did not change
function in this way.13 PR functional activities of cyanopyrrole-
containing oxindoles were instead controlled by 3,3-substitu-
tions.12 These results suggested that the dominance of the
cyanopyrrole motif on PR functional activity was template-
dependent. To examine the SAR of 7-(50-cyanopyrrol-2-yl)benz-
oxazepinones, numerous analogs were prepared and tested in
the T47D PR alkaline phosphatase functional assay. The results
are shown in Table 1.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
0.9
0.2
1.1
245.8
Me 137.7
Me
H
H
Me
Me
H
Me
Me
Me
–C5H10
Me
Me
Me
Me
Me
Et
n-Propyl
i-Propyl
Thien-2-yl
Fur-2-yl
Phenyl
H
Me
H
H
Me
H
Me
Me
Me
Me
Me
Me
Me
Me
3.3
3.3
30.5
0.7
0.8
1.1
0.8
10.7
–
Thien-2-yl
Thien-2-yl
Thien-3-yl
Thien-3-yl
Fur-2-yl
Thien-2-yl
Thien-2-yl
Thien-2-yl
Thien-2-yl
Fur-2-yl
3.8
2.4
3.4
0.4
14.6 75
56.6
36.5
11.3 60
6.6 28.4
14.3 36
197.4
Phenyl
As illustrated in Table 1, the size of the R1/R2 substituents at the
5-position had a marked impact on the type of functional activity
as well as the potency of 7-(50-cyanopyrrol-2-yl)benzoxazepinon-
es. Compounds 4 and 5 with a single methyl group at the 5-posi-
tion were much less potent compared to their 5,5-dimethyl
disubstituted congeners (6 and 7) (Table 1).
Increasing the size of 5,5-substitution to a spiral cyclohexyl
moiety (8) caused significant reduction in potency. Replacing
one of the methyl groups in compounds 6 and 7 (EC50 = 3.3 nM)
with a thienyl or furyl ring (9–13, EC50 = 0.4–1.1 nM) resulted in
greater than threefold improvement in potency and gave numer-
ous PR agonists with potency comparable to that of steroidal
progesterone (1). It was noted that N-methyl substitution on
50-Cl-thien-2-yl- 50-Cl-thien-2-yl- Me
30-Cl-phenyl
Me
Et
30-Cl-phenyl
Thien-2-yl
Thien-2-yl
Phenyl
Me
Me
Me
Me
175.1
37.5
119.8
500.0
Phenyl
a
Fifty percent effective concentration of tested compounds on alkaline phos-
phatase activity in the human T47D breast carcinoma cell line.
b
Fifty percent inhibitory concentration of tested compounds on 1 nM proges-
terone-induced alkaline phosphatase activity in the human T47D breast carcinoma
cell line. Values represent the average of at least duplicate determinations. The
standard deviation for the assays was typically 20% of the mean or less.
c
Value was 50% inhibitory concentration of tested compounds on 1 nM 3H-
progesterone binding at PR using human T47D breast carcinoma cell line cytosol.
The standard deviations for these assays were typically 20% of mean or less. Blanks
in EC50 and IC50 columns indicate that values were not measured.

J. C. Kern et al. / Bioorg. Med. Chem. Lett. 18 (2008) 5015–5017
5017
MRb
Table 2
Table 3
PR alkaline phosphatase activity of 7-(50-cyanopyrrol-2-yl) benzoxazepinone stereo-
isomers
Antagonist cross-activities (IC50 nM) of 2, 12, 13, 17, and 18
Compound
PRa
ERb
ARb
GRb
R1
R2
2
0.2
5000
6.9
0.6
127
120
>3000
>3000
590
440
155
2300
2800
0.8c
0.4c
11.3
6.6
>10,000
>10,000
>10,000
>10,000
325
215
775
740
NC
12
13
17
18
O
N
R3
N
O
H
a
Fifty percent inhibitory concentration of tested compounds on 1 nM proges-
terone-induced alkaline phosphatase activity in the human T47D breast carcinoma
cell line. Values represent the average of at least duplicate determinations. The
standard deviations for these assays were typically 20% of the mean or less.
Experimental values represented the average of at least duplicate determina-
tions. The standard deviation for these assays was typically 30% of mean or less.
See Ref. 12 for details.
Compound
R1
R2
R3
EC50 (nM)
IC50 (nM)
a
b
11
Me
Me
Me
Et
Et
Et
Thien-3-yl
Thien-3-yl
Thien-3-yl
Thien-2-yl
Thien-2-yl
Thien-2-yl
H
H
H
Me
Me
Me
1.1
110.0
0.5
(S)-11*
(R)-11*
14
b
14.6
17.1
10.0
(S)-14*
(R)-14*
c
EC50 values.
*
Absolute stereochemistry was not determined. The absolute stereochemistry
was arbitrarily assigned for both pair of enantiomers.
AR, GR, and MR, they were still over 100-fold functionally selective
against these receptors.
a
Fifty percent effective concentration of tested compounds on alkaline phos-
phatase activity in the human T47D breast carcinoma cell line.
For PR antagonists 17 and 18, no significant activity was ob-
served at ER and GR in contrast to the mifepristone (2) which
demonstrated equal potency at PR and GR. Against AR and GR,
both 17 and 18 showed better selectivity compared to that of
mifepristone.
b
Fifty percent inhibitory concentration of tested compounds on 1 nM proges-
terone-induced alkaline phosphatase activity in the human T47D breast carcinoma
cell line. Values represent the average of at least duplicate determinations. The
standard deviation for the assays was typically 20% of the mean or less.
In summary, we have examined a class of novel 7-(50-cyanopyr-
rol-2-yl)benzoxazepinones as PR modulators. The SAR reveals that
the size of substituents at the 5-position has a profound impact on
the PR functional activity and potency. With an appropriate choice
of 5-substitution, both PR agonists and antagonists can be achieved
from the 7-(50-cyanopyrrol-2-yl)benzoxazepinone scaffold. The
SAR effort has led to a number of potent PR agonists and antago-
nists with good to excellent selectivity against other steroidal
receptors.
the pyrrole ring did not have any significant impact on either
potency or functional activity compared to their unsubstituted
analogs (e.g., 6, 9, 11 vs 7, 10, 12) and all analogs (4–13) are
PR agonists. Surprisingly, substitution of an ethyl group (14)
for the methyl moiety (10) switched PR agonism to PR antago-
nism, but with reduced potency in the functional assay. Increas-
ing size from ethyl to propyl groups (15 and 16) maintained PR
antagonist activity with slightly reduced potency. 5,5-Diaryl ana-
logs 17–19 also showed good PR antagonist potency with an IC50
ranging from 6.6 to 14.3 nM. A greater than 10-fold loss of po-
tency was observed when chlorine was added to the 5-aryl sub-
stituents (20, 21) suggesting a size limitation in this region of
the molecule (or an unfavorable electronic effect due to chlo-
rine). Methyl substitution at the 1-position amide nitrogen of
the benzoxazepinone (22–24) significantly decreased potency
but did not change the mode of PR functional activity.
Acknowledgments
We thank Drs. Ron Magolda and Magid Abou-Gharbia for their
support and the assistance of the Department of Analytical Chem-
istry for analytical data.
References and Notes
The binding affinities of several potent analogs were deter-
mined at PR from human T47D breast carcinoma cell line cytosol
using [3H]-progesterone as the radio-labeled competitor. In gen-
eral, these compounds demonstrated good binding affinities to
PR. Consistent with their potency in the functional assay, the PR
agonists were more potent binders than the antagonists.
1. Mangelsdorf, D. J.; Thummel, C.; Beato, M.; Herrlich, P.; Schuetz, G.; Umesono,
K.; Blumberg, B.; Kastner, P.; Mark, M. Cell (Cambridge, Mass.) 1995, 83, 835.
2. Yuzpe, A. A. J. Reprod. Med. 2002, 47, 967.
3. Brown, A.; Cheng, L.; Lin, S.; Baird, D. T. J. Clin. Endocrinol. Metabol. 2002, 87, 63.
4. Kettel, L. M.; Murphy, A. A.; Morales, A. J.; Yen, S. S. Human Reprod. 1994,
9(Suppl. 1), 116.
5. Kettel, L. M.; Murphy, A. A.; Morales, A. J.; Yen, S. S. Am. J. Obst. Gynecol. 1998, 178, 1151.
6. Murphy, A. A.; Kettel, L. M.; Morales, A. J.; Roberts, V. J.; Yen, S. S. J. Clin.
Endocrinol. Metabol. 1993, 76, 513.
7. Murphy, A. A.; Morales, A. J.; Kettel, L. M.; Yen, S. S. Fertility Sterility 1995, 64, 187.
8. Collins, M. A.; Hudak, V.; Bender, R.; Fensome, A.; Zhang, P.; Miller, L.;
Winneker, R. C.; Zhang, Z.; Zhu, Y.; Cohen, J.; Unwalla, R. J.; Wrobel, J. Bioorg.
Med. Chem. Lett. 2004, 14, 2185.
9. Fensome, A.; Bender, R.; Chopra, R.; Cohen, J.; Collins, M. A.; Hudak, V.;
Malakian, K.; Lockhead, S.; Olland, A.; Svenson, K.; Terefenko, E. A.; Unwalla, R.
J.; Wilhelm, J. M.; Wolfrom, S.; Zhu, Y.; Zhang, Z.; Zhang, P.; Winneker, R. C.;
Wrobel, J. J. Med. Chem. 2005, 48, 5092.
10. Zhang, P.; Terefenko, E. A.; Fensome, A.; Wrobel, J.; Winneker, R.; Lundeen, S.;
Marschke, K. B.; Zhang, Z. J. Med. Chem. 2002, 45, 4379.
11. For separate work on the 7-phenyl based 1,5-dihydrobenzo[e][1,4]oxazepin-2-
ones, see Ref.: Zhang, P.; Kern, J. C.; Terefenko, E. A.; Fensome, A.; Unwalla, R.;
Zhang, Z.; Cohen, J.; Berrodin, T. J.; Yudt, M. R.; Winneker, R. C.; Wrobel, J.
Bioorg. Med. Chem. 2008, 16, 6589.
12. Fensome, A.; Adams, W. R.; Adams, A. L.; Berrodin, T. J.; Cohen, J.; Huselton,
C.; Illenberger, A.; Kern, J. C.; Hudak, V. A.; Marella, M. A.; Melenski, E. G.;
McComas, C. C.; Mugford, C. A.; Slayden, O. D.; Yudt, M.; Zhang, Z.;
Zhang, P.; Zhu, Y.; Winneker, R. C.; Wrobel, J. E. J. Med. Chem. 2008, 51,
1861.
The impact of chirality at the 5-position on PR activity was
examined by chiral resolution of compounds 11 and 14. As illus-
trated in Table 2, both enantiomers retained the same functional
activity as their respective racemate. However, for PR agonist 11,
the eutomer (EC50 = 0.5 nM) is two orders of magnitude more po-
tent than its distomer (EC50 = 110.0 nM) suggesting a clear stereo-
chemical preference for PR agonism at the binding site. In contrast,
both enantiomers of antagonist 14 showed similar PR antagonist
potency indicating little impact of chirality on 14’s action at PR.
Compounds12, 13, 17, and 18 were evaluated for their selectiv-
ity against other steroidal receptors by using a Gal4-DNA binding
domain (DBD)-hormone receptor ligand binding domain (LBD)
one-hybrid assay for each receptor (Table 3).14 When tested in
the agonist mode, these compounds did not show any significant
activity at estrogen (ER), androgen (AR), glucocorticoid (GR), and
mineralcorticoid (MR) receptors. When tested in the antagonist
mode, compounds 12 and 13 did not show any significant activity
at ER. Although 12 and 13 showed moderate antagonist potency at
13. Terefenko, E. A.; Kern, J.; Fensome, A.; Wrobel, J.; Zhu, Y.; Cohen, J.; Winneker,
R.; Zhang, Z.; Zhang, P. Bioorg. Med. Chem. Lett. 2005, 15, 3600.
14. Sadowski, I.; Bell, B.; Broad, P.; Hollis, M. Gene 1992, 118, 137.