Synthesis and structure-activity relationship of diarylamide derivatives as selective inhibitors of the proliferation of human coronary artery smooth muscle cells

Article abstract of DOI:10.1016/S0960-894X(00)00717-4

A series of diarylamide derivatives were synthesized and evaluated for their inhibitory activities against human coronary artery smooth muscle cells (SMCs) and human coronary artery endothelial cells (ECs). Compound 2w was superior to the lead compound, Tranilast, in terms of the potency of the activity and cell selectivity.

Full text of DOI:10.1016/S0960-894X(00)00717-4

Bioorganic & Medicinal Chemistry Letters 11 (2001) 549±551
Synthesis and Structure±Activity Relationship of Diarylamide
Derivatives as Selective Inhibitors of the Proliferation
of Human Coronary Artery Smooth Muscle Cells
Haruhisa Ogita, Yoshiaki Isobe, Haruo Takaku, Rena Sekine, Yuso Goto,
Satoru Misawa and Hideya Hayashi*
Pharmaceuticals & Biotechnology Laboratory, Japan Energy Corporation, 3-17-35, Niizo-Minami, Toda-shi, Saitama 335-8502, Japan
Received 13 October 2000; accepted 8 December 2000
AbstractÐA series of diarylamide derivatives were synthesized and evaluated for their inhibitory activities against human coronary
artery smooth muscle cells (SMCs) and human coronary artery endothelial cells (ECs). Compound 2w was superior to the lead
compound, Tranilast, in terms of the potency of the activity and cell selectivity. # 2001 Elsevier Science Ltd. All rights reserved.
Introduction
Acid-catalytic ester formation with sulfuric acid or
amide formation with diphenylphosphoryl chloride
(DPPCl) as a condensation reagent of 4,5-dimethoxy-2-
nitro benzoic acid, followed by catalytic hydrogenation
with 5% Pd/C gave the corresponding compounds 3c±f in
a good yield (70±80%). Other substituted anthranillic
amides and esters were given in the same way. The sub-
stituted benzoyl chloride 6 were prepared from the
corresponding benzoic acid 5 with thionyl chloride.
Compounds 6 were used without puri®cation. The
condensation of 3 with 6 in the presence of triethyl-
amine a€orded 2a, 2b, 2e±ad in a good yield (70±90%).
In the case of hydroxy groups containing compounds,
the hydroxy groups were protected as acetoxy groups
before this condensation. Compounds 2c and 2d were
prepared from the corresponding aniline 3a or 3b with
3,4-dimethoxy benzoyl chloride. Basic hydrolysis of 2d
provided 2e.
Proliferation and migration of smooth muscle cells
(SMCs) play a pivotal role in restenosis and in progres-
sion of atherosclerosis.1 Arterial injury results in the
migration of SMCs into the intimal layer of the arterial
wall, where they proliferate and synthesize extracellular
matrix components. It has been reported that many
growth factors induce the proliferation of SMCs in vitro
and in vivo.2 Among them, platelet-derived growth fac-
tor (PDGF) is an important regulator of SMCs beha-
vior through its well-de®ned actions as a potent
chemoattractant and a strong mitogen.3 Recently, Tra-
nilast has been reported to markedly inhibit the pro-
liferation and migration of SMCs and ECs,4 and it
showed a potent preventive e€ect for restenosis after
PTCA in clinical study.5 On the other hand, it has been
reported that the selective inhibition of the proliferation of
SMCs for ECs was preferable for the treatment of rest-
enosis.6 So we tried to search for more potent and SMCs
selective compounds by the modi®cation of Tranilast.
A series of these compounds were evaluated for their
inhibitory activities on PDGF-induced proliferation of
Chemistry and Biology
The synthesis of diarylamide derivatives 2a±2ad7 were
outlined in Scheme 1.
*Corresponding author. Tel.: +81-48-433-2194; fax: +81-48-443-1605;
e-mail: hhayashi@j-energy.co.jp
Figure 1. Structure of Tranilast and its derivatives.
0960-894X/01/$ - see front matter # 2001 Elsevier Science Ltd. All rights reserved.
PII: S0960-894X(00)00717-4

550
H. Ogita et al. / Bioorg. Med. Chem. Lett. 11 (2001) 549±551
Scheme 1. Synthesis of compounds 2a±2ad. Reagents and conditions: (a) 3,4-(OMe)2-PhCOCl or 3,4,5-(OMe)3-PhCOCl, Et3N/CH2Cl2; (b) NaOH/
MeOH (c) H2SO4/EtOH; (d) DPPCl, Et3N/CHCl3 then NH3 or MeNH2 or Me2NH; (e) H2, 5% Pd/C/EtOH; (f) SOCl2/CHCl3, re¯ux; (g) Ac2O,
Et3N/DMF; (h) Et3N/CH2Cl2.
SMCs and FBS-induced proliferation of ECs. Inhibition
3
Compound 2k (dimethoxy groups at R1 and ethoxy
carbonyl group at X moiety) showed more potent
activity than Tranilast and its related compounds (2a,
2b). The distance between the ring A and the ring B did
not in¯uence the activity (2f, 2j, 2k). In the case of
dimethoxy substitution at R1, other groups at X moiety
such as hydrogen, cyano, carboxyl and substituted car-
bamoyl groups were less active (2c, 2d, 2e, 2h, 2i), but
the carbamoyl group (2g) showed almost the same
activity as the ethoxy carbonyl group (2f). For the
of proliferation of these cells was determined by H-
thymidine incorporation as a previously reported
method with a minor modi®cation.8
Results and Discussion
The inhibitory activities of 2a±ad on PDGF-induced
proliferation of SMCs are shown in Tables 1±3.
Table 1. IC50 values of the compounds 2a±k for inhibition of proliferation of SMCs and ECs
No.
R1
X
Y
SMCs
IC50 (mM)a
ECs
IC50 (mM)b
[ECs]/[SMCs]
Tranilast
H
H
H
CO2H
CO2Et
CONH2
H
CN
CO2H
CO2Et
CONH2
CONHMe
CONMe2
CO2Et
CO2Et
(E)-CHˆCH
24.5
>50
16.7
19.1
9.5
34.5
nt
nt
nt
0.8
2
2a
2b
2c
2d
2e
2f
2g
2h
2i
(E)-CHˆCH
(E)-CHˆCH
4,5-(OMe)2
4,5-(OMe)2
4,5-(OMe)2
4,5-(OMe)2
4,5-(OMe)2
4,5-(OMe)2
4,5-(OMe)2
4,5-(OMe)2
4,5-(OMe)2
Ð
Ð
>2.0
>2.0
>2.0
0.85
0.72>10
>2.0
>2.0
0.8
Ð
Ð
Ð
Ð
Ð
6
7
6
>14
nt
nt
4.7
2j
2k
CH2
(E)-CHˆCH
1.24.1
4
nt: not tested.
aInhibitory activity against the proliferation of SMCs induced by PDGF-BB (20 ng/mL).
bInhibitory activity against the proliferation of ECs induced by 5% FBS.

H. Ogita et al. / Bioorg. Med. Chem. Lett. 11 (2001) 549±551
551
Table 2. IC50 values of the compounds 2d, 2l±x for inhibition of
proliferation of SMCs and ECs
number of methoxy group substitutions in ring B, the
order of the potency was 3 (2w, 2x) >2 (2f) >1 (2l, 2m,
2n), and the position of it was para (2l) >ortho (2m) >
meta (2n). Polar groups like hydroxy groups (acetoxy
groups) and amino groups on ring B instead of methoxy
groups resulted in decreased activity. Other substituents
at R1 such as di¯uoro, nitro, amino, methyl, and chloro
groups are less active (Table 3). Among these com-
pounds, 2w was the most potent (IC50=0.31 mM), and
was about 80-fold more potent than Tranilast. The
compounds with IC50 values less than 2.0 mM were fur-
ther evaluated against the proliferation of ECs. IC50
values of 2w for SMCs and for ECs were 0.31 and 4.6
mM, respectively, displaying selectivity about 15 times
for SMCs. In contrast, IC50 values of Tranilast were
24.5 and 19.1 mM, respectively, displaying selectivity
about 0.8 times for SMCs. So, compound 2w was
superior to Tranilast in the strength of the activity and
cell selectivity. The mechanism of the action of these
derivatives has not been determined. Although several
reseachers have reported the mechanism of Tranilast,9
the main mechanism remained unclear. So the de®nition
of main target molecules for these compounds and the
structural optimization are underway.
No.
R2
SMCs
ECs
[ECs]/[SMCs]
7
IC50 (mM)a IC50 (M)b
2f
2l
3,4-(OMe)2
4-OMe
2-OMe
3-OMe
4-OAc
0.85
0.61
0.8
1.6
1.3
2.2
2.8
1.8
>2.0
3.1
6
<2.0
3.8
6.1
5.24
nt
nt
7.24
nt
nt
nt
4.6
2.9
2m
2n
2o
2p
2q
2r
2s
2t
2u
2w
2x
5
4
3,4-(OAc)2
3-OMe-4-OAc
3-NO2-4-OH
3-NH2-4-OH
3,5-(OMe)2-4-OAc
3,4,5-(OAc)3
3,4,5-(OMe)3
2,3,4-(OMe)3
>2.0
0.31
0.41
15
7
nt: not tested.
aInhibitory activity against the proliferation of SMCs induced by
PDGF-BB (20 ng/mL).
bInhibitory activity against the proliferation of ECs induced by 5%
FBS.
References and Notes
1. Ross, R. Nature 1993, 362, 801.
2. Reidy, M. A. Arch. Pathol. Lab. Med. 1992, 116, 1276.
3. Ross, R.; Raines, E. W.; Bowen-Pope, D. F. Cell 1986, 46, 155.
4. (a) Tanaka, K.; Honda, M.; Kuromachi, T.; Morioka, S.
Atherosclerosis 1994, 107, 179. (b) Isaji, M.; Miyata, H.; Aji-
sawa, Y.; Takehata, Y.; Yoshimura, N. Br. J. Pharmacol.
1997, 122, 1061.
Table 3. IC50 values of the compounds 2y±z, 2aa±ad for inhibition of
proliferation of SMCs and ECs
5. Tamai, H.; Katoh, O.; Suzuki, S.; Fujii, K.; Aizawa, T.;
Takase, S.; Kurogane, H.; Nishikawa, H.; Sone, T.; Sakai, K.;
Suzuki, T. Am. Heart. J. 1999, 138, 968.
6. Yasunari, S.; Nagai, R. In Kekkan Remodeling to Shushokuin-
shi; Yazaki, Y., Ed.; Medical Review Co. Ltd, 1997; p 295.
7. Selected data for compound 2w: 1H NMR (DMSO-d6) 1.32 (t,
3H, J=7.3 Hz), 3.75 (s, 3H), 3.80 (s, 3H), 3.87 (s, 6H), 3.88 (s, 3H),
4.34 (q, 2H, J=7.3 Hz), 7.27 (s, 2H), 7.47 (s, 1H), 8.30 (s, 1H),
11.64 (s, 1H); TOF-MS: (M+H) 420 calcd 419.43 All compounds
were fully characterized by 1H NMR and TOF-MS.
No.
R1
SMCs
IC50 (mM)a
ECs
IC50 (mM)b
[ECs]/[SMCs]
2y
2z
2aa
2ab
2ac
2ad
H
>2.0
2>1 0
1.6
>2.0
>2.0
>2.0
nt
>5
<2.0
nt
nt
nt
4,5-F2
5-NO2
5-NH2
5-Me
4-Cl
8. Hishikawa, K.; Nakaki, T.; Hirahashi, J.; Marumo, T.;
Saruta, T. Eur. J. Pharmacol. 1995, 291, 435.
9. (a) Koyama, S.; Takagi, H.; Otani, A.; Suzuma, K.; Nishi-
mura, K.; Honda, Y. Br. J. Pharmacol. 1999, 127, 537. (b)
Miyazawa, K.; Hamano, S.; Ujiie, A. Br. J. Pharmacol. 1996,
118, 915. (c) Kusama, H.; Kikuchi, S.; Tazawa, S.; Katsuno,
K.; Baba, Y.; Zhai, Y. L.; Nikaido, T.; Fujii, S. Atherosclerosis
1999, 143, 307. (d) Takahashi, A.; Taniguchi, T.; Ishikawa, Y.;
Yokoyama, M. Circ. Res. 1999, 84, 543.
nt: not tested.
aInhibitory activity against the proliferation of SMCs induced by
PDGF-BB (20 ng/mL).
bInhibitory activity against the proliferation of ECs induced by 5% FBS.