Synthesis and biological evaluation of [4-(2-phenylethenesulfonylmethyl) phenyl]-quinazolin-4-yl-amines as orally active anti-cancer agents

Article abstract of DOI:10.1016/j.bmcl.2003.10.020

A new series of [4-(2-phenylethenesulfonylmethyl)phenyl]quinazolin-4-yl- amines was prepared and tested for its in vitro cytotoxic activity against a panel of 12 human cancer cell lines. Compounds 9, 15, 24 and 31 showed good in vitro activity and were further tested for their in vivo efficacy in the HT-29 human colon adeno carcinoma xenograft model. Compound 9 exhibited promising activity in this model. Dose-response studies for this compound against HT-29 human colon adeno carcinoma xenografts at 100, 200 and 400 mg/kg doses were performed.

Full text of DOI:10.1016/j.bmcl.2003.10.020

Bioorganic & Medicinal Chemistry Letters 14 (2004) 67–71
Synthesis and biological evaluation of
[4-(2-phenylethenesulfonylmethyl)phenyl]-quinazolin-4-yl-amines
as orally active anti-cancer agents§
Vedula M. Sharma,a,* K. V. Adi Seshu,a V. Chandra Sekhar,a Sachin Madan,a
B. Vishnu,a P. Aravind Babu,a C. Vamsee Krishna,a J. Sreenu,a V. Ravi Krishna,a
A. Venkateswarlu,a Sriram Rajagopal,b R. Ajaykumarb and T. Sravan Kumarb
aDiscovery Chemistry, Dr. Reddy’s Laboratories, Discovery Research, Miyapur, Hyderabad-500 049, India
bDiscovery Biology, Dr. Reddy’s Laboratories, Discovery Research, Miyapur, Hyderabad-500 049, India
Received 11 July 2003; accepted 9 October 2003
Abstract—A new series of [4-(2-phenylethenesulfonylmethyl)phenyl]quinazolin-4-yl-amines was prepared and tested for its in vitro
cytotoxic activity against a panel of 12 human cancer cell lines. Compounds 9, 15, 24 and 31 showed good in vitro activity and were
further tested for their in vivo efficacy in the HT-29 human colon adeno carcinoma xenograft model. Compound 9 exhibited pro-
mising activity in this model. Dose–response studies for this compound against HT-29 human colon adeno carcinoma xenografts at
100, 200 and 400 mg/kg doses were performed.
# 2003 Elsevier Ltd. All rights reserved.
A recent trend in the discovery of anti-cancer agents is
to design small molecules which interfere with signal
transduction processes by blockingthe cell surface
receptor, by inhibitinga growth factor receptor tyrosine
kinase or by inhibitingdownstream signalingproteins
such as mitogen-activated protein (MAP) kinase. These
signal transduction inhibitors are new type of anti-can-
cer agents which may have several beneficial effects such
as non-toxic, cytostatic and may be administered orally.
Two anti-cancer drugs Imatinib (Gleevec)1 and Gefiti-
nib (Iressa)2 (Fig. 1) have already received regulatory
approval in cancer indications. 4-Anilinoquinazolines, a
class of biologically active compounds, are known to
exhibit cytotoxic activity through various mechanisms.
The inhibitory properties of these compounds against
epidermal growth factor receptor tyrosine kinases
Figure 1. Structures of Imatinib mesylate (Gleevec) and Gefitinib (Iressa).
Keywords: [4-(2-Phenylethenesulfonylmethyl)phenyl]-quinazolin-4-yl-amines; Orally active anti-cancer agents; HT-29 human colon adeno carcinoma
xenograft.
§DRL Publication No. 326.
* Correspondingauthor. Tel.: +91-40-2304-5439; fax: +91-40-2304-5438; e-mail: sarmavm@drreddys.com
0960-894X/$ - see front matter # 2003 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmcl.2003.10.020

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V. M. Sharma et al. / Bioorg. Med. Chem. Lett. 14 (2004) 67–71
(EGF-RTK),3 p56lck,4 and vascular endothelial growth
factor receptor tyrosine kinases (VEGF-RTK),5ꢀ7 are
well documented.
In continuation of our ongoing cancer research
program,8ꢀ10 we were lookingfor novel quinazoline
derivatives with modifications at the C(4)-aniline sub-
stituent. We report here the synthesis of a number
of [4-(2-phenylethenesulfonylmethyl)phenyl]-quinazo-
lin-4-yl-amines (Fig. 2) and the evaluation of their
biological activity of in vitro growth inhibition of
cancer cells, and in vivo prolongation of cancer sur-
vival in animals.
Figure 2. Structure of [4-(2-phenylethenesulfonylmethyl)phenyl]-
quinazolin-4-yl-amine.
Scheme 1. (a) HSCH2COOH (2 equiv), KOH (4 equiv), water, DMSO, rt, 0.5 h, 93%; (b) potassium peroxymonosulfate (OxoneTM; 2 equiv),
.
t-BuOH/water/CH2Cl2 (1:1:1), rt, 12 h, 98%; (c) benzylamine (0.2 equiv), glacial acetic acid, reflux, 3–5 h, 85–90%; (d) SnCl2 2H2O (4 equiv),
EtOH, reflux, 2–4 h, 75–85%; (e) 2-propanol, reflux, 3–5 h, 88–92%.

V. M. Sharma et al. / Bioorg. Med. Chem. Lett. 14 (2004) 67–71
69
The general procedure for the synthesis of compounds
8–33 is outlined in Scheme 1. (4-Nitrobenzylsulfanyl)-
acetic acid (2) was prepared from 4-nitrobenzylbromide
The quinazoline derivatives prepared in this study were
tested for their cytotoxic activity against breast (MCF7/
ADR, MCF7), CNS (U251), colon (SW620, HT29),
lung(H522), melanoma (UACC62), ovarian (SKOV3,
OVCAR8), prostate (DU145, PC3) and renal (ACHN)
human cancer cell lines. The selected active analogues
were then further evaluated for their in vivo anti-cancer
activity with HT-29 human colon adeno carcinoma
xenografts. The E,Z isomers of the compounds were
tested for their activity without separation. The con-
centration that caused 50% inhibition of cancer cell
growth against various cancer cell lines were expressed
as GI50 values and were given in Table 1. We started our
SAR studies with an unsubstituted [4-(2-phenylethene-
sulfonylmethyl)phenyl]-quinazolin-4-ylamine (8). This
particular compound showed activity only against
SKOV3 and DU145 cell lines with GI50 values of 5.0
and 2.0 mM, respectively. Then various analogues were
prepared with different substitutions on ringD ( Fig. 2).
Among4-substituted derivatives 9, 10, 12, 14 and 19 on
ringD, 4-fluoro ( 9)14 compound exhibited very good
activity against various cell lines. Particularly, renal,
CNS and prostate cell lines were highly sensitive
towards this compound with GI50 values in the range of
0.01–1.0 mM. This compound was also active against
HT29 of colon and SKOV3, OVCAR8 of ovarian cell
lines in the range of 1.0–2.0 mM. The 4-hydroxy com-
pound (19) showed activity at submicromolar con-
centrations in CNS and renal cell lines and showed
moderate activity in HT-29 and OVCAR8 cell lines.
However 4-cyano (10), 4-bromo (12) and 4-chloro (14)
compounds were found to be inactive. Amongthe dis-
and mercaptoaceticacid. The sulfide of 2 was oxidized to
TM
sulfone usingpotassium peroxymonosulfate (Oxone
)
to give (4-nitrophenylmethanesulfonyl)acetic acid (3).
Compound 3 on Knoevenagel reaction with various
substituted benzaldehydes (4) in glacial aceticacid in the
presence of benzylamine, yielded respective 1-nitro-4-(2-
phenylethenesulfonylmethyl)-benzenes (5). The nitro
groups of compounds 5 were reduced with stannous
chloride in refluxingethanol to give corresponding4-(2-
phenylethenesulfonylmethyl)-phenylamines (6) in good
yields. The amino compounds (6) were finally reacted
with different substituted chloroquinazolines (7)11,12 in
2-propanol under reflux conditions to give [4-(2-
phenylethenesulfonylmethyl)phenyl] - quinazolin - 4 - yl -
amines (8–33).
Quinazoline derivatives (38–40) havinga side chain at
the C-6 position were prepared as shown in Scheme 2. 6-
Acetyloxy-7-methoxy-4-chloroquinazoline (34)11,12 was
reacted with 4-(2-phenylethenesulfonylmethyl)-phenyl-
amines (6) in refluxing2-propanol to give compounds
35. Deprotection of acetyl group of compounds 35 with
ammonium hydroxide resulted in compound 36. The
hydroxy compounds (36) were reacted with 1-bromo-2-
chloroethane/1-bromo-3-chloropropane to give com-
pounds 37 havinga terminal halogen. Compounds 38–
40 with morpholinoethoxy/propoxy substituents at the
C-6 position were obtained from corresponding
compounds 37 by reaction with morpholine.
Scheme 2. (a) 2-Propanol, reflux, 3–4 h, 75–80%; (b) aq NH3, MeOH, rt, 2–4 h, 65–72%; (c) 1-bromo-2-chloroethane/1-bromo-3-chloropropane
(2 equiv), K2CO3 (3 equiv), DMF, rt, 6–8 h, 58–65%; (d) morpholine (2 equiv), K2CO3 (2 equiv), KI (1 equiv), DMF, 80 ꢁC, 2–4 h, 50–65%.

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V. M. Sharma et al. / Bioorg. Med. Chem. Lett. 14 (2004) 67–71
Table 1. In vitro cytotoxic activities of [4-(2-phenylethenesulfonylmethyl)phenyl]-quinazolin-4-yl-amines
GI50 values in mM
Compd
Breast
MCF7/ADR
CNS
Colon
LungMelanoma
Ovarian
Prostate
Renal
MCF7
U251
SW620
HT29
H522
UACC62
SKOV3 OVCAR8 DU145
PC3
ACHN
8
9
>100
nt
>100
74.0 >100
16.0 0.01
>100 >100
28.0 11.0
91.0 >100
>100
100.0
>100
41.0
>100
9.0
>100
>100
>100
5.0
>100
21.0
>100
6.0
13.0
2.0
>100
100.0
100.0
10.0
30.0
>100
5.0
2.0
>100
>100
2.0
>100
14.0
38.0
5.0
>100
4.0
>100
100.0
100.0
1.0
0.1
2.0
2.0
0.3
>100
nt
55.0
1.0
>100
3.0
>100
1.0
>100
35.0
42.0
7.0
43.0
19.0
>100
100.0
100.0
14.0
11.0
34.0
2.0
58.0
0.01
>100
28.0
0.2
>100
>100
0.1
31.0
73.0
100.0
0.02
nt
nt
nt
nt
0.1
16.0
8.0
1.0
>100
11.0
>100
17.0
13.0
>100
32.0
>100
45.0
46.0
12.0
nt
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
38
39
40
22.0
22.0
1.0
3.0
54.0
2.0
69.0
44.0
39.0
14.0
>100
>100
>100
5.0
>100
66.0
100.0
nt
nt
nt
nt
nt
>100
85.0
100.0
13.0
52.0
4.0
38.0
49.0
4.0
77.0
14.0
86.0 >100
73.0
24.0
>100
>100
nt
nt
nt
21.0
100.0
100.0
100.0
100.0
0.3
100.0
100.0
100.0
5.0
100.0
100.0
2.0
100.0
100.0
100.0
19.0
17.0
3.0
1.0
3.0
2.0
nt
nt
14.0 >100
27.0 >100
10.0 20.0
45.0 >100
94.0 9.0
>100
nt
5.0
46.0
11.0
30.0
>100
nt
nt
nt
1.0
5.0
2.0
13.0
27.0
8.0
40.0
100.0
76.0
>100
nt
>100
6.0
>100
8.0
100.0
>100
nt
15.0
28.0
2.0
22.0
3.0
3.0
>100
3.0
15.0
100.0
32.0 >100
42.0
4.0
4.0
32.0
100.0
25.0
4.0
28.0
100.0
100.0
59.0
>100
>100
>100
6.0
>100
24.0
100.0
>100
4.0
30.0
32.0
53.0
55.0
100.0
>100
58.0
100.0
38.0
>100
73.0
>100
5.0
>100
9.5
100.0
28.0
5.0
>100
32.0
48.0
>100
nt
8.0
>100
>100
>100
24.0
>100
7.0
nt
3.0
>100
>100
15.0
>100
11.0
>100
>100
2.0
>100
13.0
>100
>100
>100
>100
2.0
>100
5.0
100.0
>100
7.0
>100
72.0
>100
21.0
>100
63.0
100.0
55.0
>100
>100
>100
2.0
>100
50.0
36.0
>100
2.4
>100
>100
>100
2.0
>100
6.0
48.0
>100
12.0
>100
37.0
>100
1.4
>100
nt
nt
4.0
1.3
>100
17.0
>100
15.0
>100
4.0
66.0
0.2
3.4
32.0
100.0
3.0
11.0
100.0
18.0
4.0
54.0
23.0
nt, not tested.
Compounds 9, 15, 24 and 31 were selected for assessing
their in vivo anti-cancer activity in HT-29 human colon
adeno carcinoma xenografts. HT-29 tumors were initi-
ated in athymic nude mice (females, 20–25 g) by
implantation of tumor fragments (ꢂ60 mm3) from
established tumors. Tumor fragments were implanted
subcutaneous (sc) into the axillary region of the animal.
When the tumors reached a size of ꢂ100 mm3, 300 mg/
kgof experimental compounds were administered per
oral once daily for 20 days (QDÂ20 schedule). The sc
tumors were measured with vernier calipers, mice were
weighed every alternate day and the volumes were cal-
Table 2. Results of Xenograft studies for compounds 9, 15, 24, 31
Compd
Dose
(mg/kg)
% Inhibition
Mortality
Max. mean%
body weight loss
9
300
300
300
300
84
22
22
68
0/6
0/6
1/6
0/6
5
7
4
12
15
24
31
ubstituted derivatives, 3,4-dichloro (11), 2,4-dichloro
(15), 2,4-difluoro (16), 2-chloro-4-fluoro (17) and 2-
fluoro-4-trifluoromethyl (18), compound 15 displayed
potent activity across most of the tested cell lines with
GI50 values ranging from 0.1 to 5.0 mM. The trisub-
stituted compound 3,5-di-t-butyl-4-hydroxy (13) was
less active.
À
Á
culated usingthe equation V ¼ D Â d2 =2 where ‘V’ is
the tumor volume in mm3, ‘D’ is the longest diameter in
mm and ‘d’ is the shortest diameter in mm.13
Amongthese, compounds 9 and 31 showed encouraging
in vivo activity (Table 2). Compound 9 was then eval-
uated for its in vivo dose–response relationship in HT-
29 human adeno carcinoma xenografts at 100, 200 and
400 mg/kg doses. The results illustrated in Figure 3.
Each bar in the figure represents the mean percentage
inhibitionꢃstandard deviation of six replicates where
control mean was set to 0%. Compound 9 at an oral
dose of 100 mg/kg exhibited 50% tumor volume reduc-
tion at the end of the treatment.
To study further SAR of compounds 9 and 15 by
introducingsubstitutions at the 6 and/or 7 positions of
quinazoline moiety, compounds 20–33 have been pre-
pared. In this group, even though compounds did not
exhibit expected enhancement in activity, compounds 24
and 31 showed moderate activity in various cell lines.
Aimingto improve the solubility of compound 31,
compound 40 with a 6-(30-morpholino)propyloxy sub-
stituent was prepared. The compound retained activity
in various cell lines though no improvement was
observed. The corresponding4-fluoro ( 39) compound
did not show activity.
In conclusion, recent efforts in the discovery of anti-
cancer drugs have been focused on searching for orally
active anti-cancer agents. Our efforts in this area lead to

V. M. Sharma et al. / Bioorg. Med. Chem. Lett. 14 (2004) 67–71
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Figure 3. Dose–response relationship of compound 9 in HT-29 human
adeno carcinoma xenografts.
the discovery of [4-(2-phenylethenesulfonylmethyl)phe-
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activity for these compounds against HT-29 human
adeno carcinoma xenografts. This class of compounds
may be further explored as anti-cancer agents by repla-
cingthe quinazoline moiety with various heterocycles to
improve their pharmacological activity.
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14. Compound 9: mp 192–193 ꢁC; IR: 3432.1, 1621.8, 1572.7,
1
1535.4 cmꢀ1; H NMR (DMSO-d6) d 4.6 (s, 2H), 7.30 (t,
2H, J=8.8 Hz), 7.38 (m, 2H), 7.49 (d, 2H, J=8.4 Hz),
7.70 (m, 4H), 7.83 (t, 1H, J=8.0 Hz), 7.88 (d, 1H,
J=8.8 Hz), 8.08 (t, 1H, J=8.4 Hz), 8.67 (d, 1H,
J=8.4 Hz), 8.80 (s, 1H), 11.30 (bs, 1H, –NH); CIMS m/z
420 (MH+, 100%); CHN: calcd C 65.86%; H 4.33%; N
10.02%. Found C 65.80%; H 4.27%; N 10.30%.