Synthesis and pharmacological evaluation of some 3-phenyl-2-substituted-3H-quinazolin-4-one as analgesic, anti-inflammatory agents

Article abstract of DOI:10.1016/j.bmc.2006.09.065

A variety of novel 3-phenyl-2-substituted-3H-quinazolin-4-ones were synthesized by reacting the amino group of 2-hydrazino-3-phenyl-3H-quinazolin-4-one with different aldehydes and ketones. The starting material 2-hydrazino-3-phenyl-3H-quinazolin-4-one was synthesized from aniline. The title compounds were investigated for analgesic, anti-inflammatory and ulcerogenic index activities. While the test compounds exhibited significant activity, compounds, 2-(N′-2-butylidene-hydrazino)-3-phenyl-3H-quinazolin-4-one (AS1), 2-(N′-3-pentylidene-hydrazino)-3-phenyl-3H-quinazolin-4-one (AS2) and 2-(N′-2-pentylidene-hydrazino)-3-phenyl-3H-quinazolin-4-one (AS3), exhibited moderate analgesic activity. The compound 2-(N′-2-pentylidene-hydrazino)-3-phenyl-3H-quinazolin-4-one (AS3) showed more potent anti-inflammatory activity when compared to the reference standard diclofenac sodium. Interestingly, the test compounds showed only mild ulcerogenic side effect when compared to aspirin.

Full text of DOI:10.1016/j.bmc.2006.09.065

Bioorganic & Medicinal Chemistry 15 (2007) 235–241
Synthesis and pharmacological evaluation of some
3-phenyl-2-substituted-3H-quinazolin-4-one
as analgesic, anti-inflammatory agents
V. Alagarsamy,a,* V. Raja Solomonb and K. Dhanabala
aMedicinal Chemistry R&D Laboratory, Arulmigu Kalasalingam College of Pharmacy, Anand Nagar, Krishnankovil-626 190, India
bMedicinal and Process Chemistry Division, Central Drug Research Institute, Lucknow-226 001, India
Received 16 August 2006; revised 25 September 2006; accepted 28 September 2006
Available online 30 September 2006
Abstract—A variety of novel 3-phenyl-2-substituted-3H-quinazolin-4-ones were synthesized by reacting the amino group of 2-hy-
drazino-3-phenyl-3H-quinazolin-4-one with different aldehydes and ketones. The starting material 2-hydrazino-3-phenyl-3H-qui-
nazolin-4-one was synthesized from aniline. The title compounds were investigated for analgesic, anti-inflammatory and
ulcerogenic index activities. While the test compounds exhibited significant activity, compounds, 2-(N0-2-butylidene-hydrazino)-
3-phenyl-3H-quinazolin-4-one (AS1), 2-(N0-3-pentylidene-hydrazino)-3-phenyl-3H-quinazolin-4-one (AS2) and 2-(N0-2-pentyli-
dene-hydrazino)-3-phenyl-3H-quinazolin-4-one (AS3), exhibited moderate analgesic activity. The compound 2-(N0-2-pentylidene-
hydrazino)-3-phenyl-3H-quinazolin-4-one (AS3) showed more potent anti-inflammatory activity when compared to the reference
standard diclofenac sodium. Interestingly, the test compounds showed only mild ulcerogenic side effect when compared to aspirin.
Ó 2006 Elsevier Ltd. All rights reserved.
1. Introduction
2-methylthio-3-substituted quinazolines12 and 2,3-disub-
stituted quinazolines13 exhibited good analgesic and
anti-inflammatory activities. The present work is an
extension of our ongoing efforts towards the develop-
ment and identification of new molecules for analgesic
and anti-inflammatory activities with minimal gastroin-
testinal ulceration side effects. On this basis, we have
synthesized some 3-phenyl-2-substituted-3H-quinazo-
lin-4-ones. The synthesized compounds were tested for
their analgesic, anti-inflammatory and ulcerogenic index
activities.
Nonsteroidal anti-inflammatory drugs (NSAIDs) are
commonly prescribed for the treatment of acute and
chronic inflammation, pain and fever. Most of NSAIDs
that are available in market are known to inhibit
isoforms, a constitutive form, COX-1 and an inducible
form, COX-2, to offer therapeutic effect. However,
long-term clinical usage of NSAIDs is associated
with significant side effects of gastrointestinal lesions,
bleeding and nephrotoxicity. Therefore, the discovery
of new safer anti-inflammatory drugs represents a
challenging goal for such a research area.1–4 On our
going medicinal chemistry research programme we have
found that quinazolines and condensed quinazolines
exhibit potent central nervous system (CNS) activities
like analgesic, anti-inflammatory5 and anticonvul-
sant.6 Quinazolin-4(3H)-ones with 2,3-disubstitution
are reported to possess significant analgesic and anti-
inflammatory7,8 and anticonvulsant activities.9 Earlier
2. Chemistry
The key intermediate 3-phenyl-2-thioxo-2,3-dihydro-
1H-quinazolin-4-one (4) was prepared by reacting ani-
line (1) with carbon disulfide and sodium hydroxide in
dimethyl sulfoxide to give sodium dithiocarbamate,
which was methylated with dimethyl sulfate to afford
the dithiocarbamic acid methyl ester (2). Compound
2 on reflux with methyl anthranilate (3) in ethanol
yielded the desired 3-phenyl-2-thioxo-2,3-dihydro-1H-
quinazolin-4-one (4) via the thiourea intermediate in
good yield (80%). The product obtained was cyclic
and not an open chain thiourea 3a. The IR spectra
we
have
documented
2-phenyl-3-substituted
quinazolines,10 2-methyl-3-substituted quinazolines,11
Keywords: Quinazoline; Analgesic; Anti-inflammatory activity.
*
Corresponding author. Tel.: +91 4563 289006; fax: +91 4563
289322; e-mail: samy_veera@yahoo.com
0968-0896/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmc.2006.09.065

236
V. Alagarsamy et al. / Bioorg. Med. Chem. 15 (2007) 235–241
S-Na+
S
b
SCH3
S
a
N
H
CS2 / NaOH
N
H
NH2
1
2
c
O
O
OCH3
NH
O
d
e
N
N
S
N
H
SCH3
N
H
N
S
H
5
4
3a
f
O
N
O
g
N
N
R1
R2
NH
N
NHNH2
AS1-AS15
N
C
6
O2N
CH3
AS1
AS6
AS11
C
H
CH2CH3
CH2CH3
CH2CH3
C
H
NO2
AS2
AS3
AS7
AS8
AS12
AS13
O
N
H
CH3
C
H
OCH3
C
H
CH2CH2CH3
Cl
H3C
AS4
AS5
AS9
AS14
AS15
C
C
H
H
CH3
C
H
CH3
C
H
Cl
AS10
Figure 1. Reagents and conditions: (a) DMSO, rt, 30 min; (b) (CH3)2SO4, 5–10 °C, 2 h; (c) methyl anthranilate (3), K2CO3, ethanol reflux for 18 h;
(d) 10% alcoholic NaOH/dil. HCl (e) 2% alcoholic NaOH, (CH3)2SO4, rt, 1 h ; (f) NH2NH2, K2CO3, ethanol reflux for 22 h; (g) (R2R1)CO; gla.
CH3COOH reflux, 33 h.
of 4 show intense peaks at 3220 cmꢀ1 for cyclic thio-
urea (NH), 1660 cmꢀ1 for carbonyl (C@O) and
1200 cmꢀ1 for thioxo (C@S) stretching. 1H NMR
spectra of 4 showed multiplet at d 7.0–9.0 for aromat-
ic (9H) protons and a singlet at d 10.5 indicating the
presence of NH.
Nucleophilic displacement of methylthio group of 5 with
hydrazine hydrate was carried out using ethanol as sol-
vent to afford 2-hydrazino-3-phenyl-3H-quinazolin-4-
one 6. The long duration of reaction (22 h) required
might be due to the presence of bulky aromatic ring at
position 3, which might have reduced the reactivity of
quinazoline ring system at C-2 position. The formation
of 6 was confirmed by the presence of NH and NH2 sig-
nals at 3334, 3280 cmꢀ1 in the IR spectra. It also showed
a peak for carbonyl (C@O) at 1680 cmꢀ1. The 1H NMR
spectra of the compound 6 showed singlet at d 5.0 and
8.7 due to NH2 and NH, respectively, a multiplet at d
7.0–8.1 was observed for aromatic (9H) protons.
The 2-methylsulfanyl-3-phenyl-3H-quinazolin-4-one (5)
was obtained by dissolving 4 in 2% alcoholic sodium
hydroxide solution with methylating agent of dimethyl
sulfate. The IR spectra of 5 showed disappearance of
NH and C@S stretching signals of cyclic thiourea.
It showed a peak for carbonyl (C@O) stretching
at 1680 cmꢀ1. The 1H NMR spectra of compound 5
showed singlet at d 2.5 due to SCH3 and a multiplet
The title compounds 3-phenyl-2-substituted quinazo-
lin-4(3H)-ones AS1–AS15 were obtained by the
condensation of amino group of 2-hydrazino-3-
at
d
7.0–8.6 was observed for aromatic (9H)
protons.

V. Alagarsamy et al. / Bioorg. Med. Chem. 15 (2007) 235–241
237
phenyl-3H-quinazolin-4-one (6) with different alde-
hydes and ketones. The formation of title product is
indicated by the disappearance of peak due to 3-
NH2 of the starting material in IR and 1H NMR
spectrum of all the compounds AS1–AS15. The IR
and 1H NMR spectrum of these compounds showed
the presence of peaks due to (N = CR1R2) carbonyl
(C@O), NH and aryl groups. The compounds
reported (Fig. 1) in this study have been thoroughly
characterized by spectral data and elemental analysis.
activity. The presence of aliphatic group and cyclo-
alkyl group (compounds AS4 and AS5) leads to
moderate decrease in activity. The presence of aryl
group at N-3 position (compounds AS6–AS8 and
A14) also results in decreasing activity. The presence
of electron-withdrawing group at N-3 aryl ring (com-
pounds AS9–AS13) results in further decrease of
activity. Compound 2-(N0-3-pentylidene-hydrazino)-3-
phenyl-3H-quinazolin-4-one (AS2) emerged as the
most active analgesic agent and it is more potent
when compared to the reference standard diclofenac
sodium (Table 1).
3. Results and discussion
3.1. Analgesic activity
3.2. Anti-inflammatory activity
Anti-inflammatory activity was evaluated by carrageen-
an-induced paw oedema test in rats.16 The anti-inflam-
matory activity data (Table 2) indicated that all the
test compounds protected rats from carrageenan-in-
duced inflammation. The compound 2-(N0-2-pentyli-
dene-hydrazino)-3-phenyl-3H-quinazolin-4-one (AS3)
showed more potent anti-inflammatory activity and
the compound AS2 showed equipotent anti-inflammato-
ry activity when compared to the reference standard
diclofenac sodium.
The analgesic activity was performed by tail-flick
technique using Wistar albino mice.14,15 The results
of analgesic activity (Table 1) indicate that all the
test compounds exhibited significant activity. Com-
pound AS1 with 2-butylidene substituent showed
good activity; with the increased lipophilicity 3-pen-
tylidene group (AS2) showed increase in activity.
Replacement of 3-pentylidene group with isomer
2-pentylidene group (compound AS3) retains the
Table 1. Percent analgesic activity of test compounds (tail-flick technique)
Compound
Dose (mg/kg)
Percent analgesic activitya
30 min
1 h
2 h
3 h
AS1
10
20
10
20
10
20
10
20
10
20
10
20
10
20
10
20
10
20
10
20
10
20
10
20
10
20
10
20
10
20
41 1.36*
55 1.71**
49 1.23*
63 1.97***
43 1.48*
56 1.72**
33 1.41*
50 1.03**
38 1.07*
50 1.26**
33 1.51*
39 1.09*
36 1.27*
47 1.63*
35 1.23*
46 1.85*
29 1.32*
37 1.43*
32 1.08*
40 1.71*
35 1.71*
42 1.22*
34 1.62*
38 1.36*
38 1.28*
42 1.47*
35 1.92*
45 1.19*
37 1.23*
43 1.36*
43 1.52*
59 1.31**
55 1.25**
69 1.08***
48 1.81*
62 1.02***
40 1.17*
51 1.76**
43 1.29*
53 1.34**
36 1.46*
41 1.55*
37 1.28*
51 1.72**
38 1.39*
50 1.97**
30 1.61*
39 1.90*
34 1.28*
45 1.37*
36 1.86*
46 1.92*
39 1.35*
45 1.47*
42 1.42*
49 1.71*
39 1.27*
46 1.39**
40 1.71*
47 1.82*
50 1.67**
61 1.92***
58 1.39**
72 1.73***
50 1.06**
62 1.24***
46 1.81*
53 1.28**
43 1.39*
57 1.65**
41 1.26*
46 1.72*
40 1.82*
55 1.42**
41 1.93*
53 1.62**
37 1.06*
42 1.83*
42 1.73*
48 1.42*
39 1.28*
49 1.31*
39 1.22*
47 1.19*
43 1.33*
50 1.06**
40 1.26*
48 1.17*
40 1.23*
50 1.71**
31 1.32*
42 1.62*
41 1.06*
49 1.22*
33 1.28*
45 1.26**
25 1.63*
37 1.69*
29 1.23*
36 1.26*
29 1.30*
36 1.51*
30 1.61*
35 1.83*
29 1.97*
31 1.72*
25 1.27*
36 1.26*
27 1.71*
35 1.07*
30 1.26*
39 1.06*
27 1.27*
33 1.22*
30 1.62*
29 1.77*
33 1.91*
39 1.62*
33 1.27*
40 1.26*
AS2
AS3
AS4
AS5
AS6
AS7
AS8
AS9
AS10
AS11
AS12
AS13
AS14
AS15
Control
Diclofenac
2
0.35
6
0.49
4
0.59
4
0.91
10
20
37 1.69*
46 0.95*
43 1.42*
55 1.16**
45 0.92*
62 1.49***
33 0.96*
39 1.13*
Significance levels *p < 0.5, **p < 0.01 and ***p < 0.001 as compared with the respective control.
a Each value represents the means SD (n = 6).

238
V. Alagarsamy et al. / Bioorg. Med. Chem. 15 (2007) 235–241
Table 2. Percent anti-inflammatory activity of test compounds (Carrageenan-induced paw oedema test in rats)
Compound
Dose (mg/kg)
Percent protection
2 h
30 min
1 h
3 h
AS1
10
20
10
20
10
20
10
20
10
20
10
20
10
20
10
20
10
20
10
20
10
20
10
20
10
20
10
20
10
20
32 1.33*
38 1.23*
34 1.38*
43 1.27*
35 1.96*
46 1.92**
29 1.02*
39 1.19*
31 1.52*
38 1.71*
27 1.23*
36 1.72*
27 1.72*
32 1.90*
28 1.27*
36 1.91*
21 1.08*
27 1.13*
26 1.46*
29 1.84*
27 1.29*
32 1.34*
25 1.26*
35 1.17*
28 1.27*
33 1.83*
30 1.08*
36 1.42*
28 1.29*
38 1.35*
5.1 0.29
32 0.63*
45 1.61**
36 1.29*
45 1.71**
35 1.90*
52 1.56***
41 1.06*
58 1.28***
33 1.09*
42 1.42*
35 1.47*
42 1.82*
33 1.23*
39 1.26*
30 1.53*
36 1.82*
32 1.22*
40 1.97*
24 1.19*
32 1.17*
28 1.84*
32 1.92*
29 1.93*
33 1.28*
28 1.71*
35 1.26*
30 1.80*
37 1.23*
32 1.93*
39 1.26*
33 1.73
37 1.12*
47 1.72**
39 1.81*
56 1.36***
42 1.23*
60 1.72***
36 1.27*
42 1.51*
38 1.72*
46 1.32**
35 1.22*
42 1.30*
31 1.90*
39 1.23*
35 1.22*
43 1.81*
26 1.08*
35 1.26*
30 1.91*
37 1.87*
34 1.27*
36 1.82*
30 1.26*
36 1.23*
32 1.22*
37 1.08*
33 1.41*
42 1.17*
34 1.25*
43 1.92*
5.7 0.32
39 1.97*
60 1.52***
26 1.23*
36 1.60*
32 1.23*
36 1.82*
33 1.22*
41 1.76*
27 1.22*
35 1.70*
29 1.41*
33 1.71*
26 1.36*
35 1.55*
23 1.27*
30 1.80*
29 1.82*
26 1.06*
20 1.22*
25 1.81*
23 1.47*
25 1.26*
22 1.32*
30 1.26*
20 1.18*
32 1.71*
24 1.06*
30 1.25*
28 1.07*
30 1.25*
25 1.18*
36 1.15*
3.2 0.93
33 0.93*
42 1.36**
AS2
AS3
AS4
AS5
AS6
AS7
AS8
AS9
AS10
AS11
AS12
AS13
AS14
AS15
38 1.08**
6.1 0.27
38 1.58*
52 0.92***
Control
Diclofenac
10
20
aEach value represents the means SD (n = 6). Significance levels *p < 0.5, **p < 0.01 and ***p < 0.001 as compared with the respective control.
withdrawing groups exhibited higher ulcer index than
the other test compounds. The high ulcer index score
for these compounds may be due to the suppression of
the prostaglandin synthesis.
Table 3. Evaluation of ulcerogenicity index
Drug
Ulcer index
AS1
AS2
0.56 1.32*
0.51 1.26*
0.53 1.53*
0.69 1.18*
0.62 1.25*
0.72 1.15*
0.65 1.28*
0.71 1.32*
0.96 1.19*
0.93 1.22
0.85 1.83*
0.81 1.29*
0.79 1.32*
0.76 1.51*
0.79 1.63*
0.15 0.32
1.73 0.41**
AS3
AS4
4. Conclusion
AS5
AS6
In our earlier studies, we observed that the presence of
alkyl groups exhibited more analgesic and anti-inflam-
matory activities over aryl groups at the N-3 posi-
tion.10–13 However, in the C-2 position also we made a
substitution in such a way as to increase lipophilicity
of the molecule. The presence of such a group enhanced
the analgesic and anti-inflammatory activities. To com-
pare the increase in activity we have taken the average
of all the readings of reaction time noted for each com-
pound for each pharmacological activity. The most
active compound of the C-2 phenyl series showed 43%
analgesic and 36% anti-inflammatory activity,10 whereas
the C-2 methyl series lead molecule showed 50% analge-
sic and 44% anti-inflammatory activity.11 Introduction
of sulfur atom at C-2 position in the above series, that
is, by placing thiomethyl group at C-2 position showed
54% analgesic and 43% anti-inflammatory activity.13
The result of the analgesic and anti-inflammatory
AS7
AS8
AS9
AS10
AS11
AS12
AS13
AS14
AS15
Control
Aspirin
aEach value represents the means SD (n = 6). Significance levels
*p < 0.05 and **p < 0.01 as compared with the respective control.
3.3. Evaluation of ulcerogenicity index
The ulcer index of the test compounds (Table 3) reveals
that the compounds AS9–AS13 possessing electron-

V. Alagarsamy et al. / Bioorg. Med. Chem. 15 (2007) 235–241
239
1
activities of the present series, one of the compound,
AS2, showed that enhancement of activity (57% analge-
sic and 45% anti-inflammatory activity). Interestingly
these compounds showed negligible ulcer index unlike
other NSAIDs. Hence, this series could be developed
as a novel class of analgesic and anti-inflammatory
agents. However, further structural modification is
planned to increase the analgesic and anti-inflammatory
activities with the decreased ulcerogenic index.
(C@O), 1200 (C@S); H NMR (CDCl3): d 7.0–9.0 (m,
9H, Ar-H), 10.5 (s, 1H, NH); MS (m/z): 254 [M+]. Anal.
Calcd for C14H10N2OS: C, 66.12; H, 3.96; N, 11.02.
Found: C, 66.15; H, 3.98; N, 11.07.
5.1.2.
2-Methylsulfanyl-3-phenyl-3H-quinazolin-4-one
(5). The 3-phenyl-2-thioxo-2,3-dihydro-1H-quinazolin-
4-one (4) (0.01 mol) was dissolved in 40 ml of 2% alco-
holic sodium hydroxide solution (95% alcohol was used
for preparation). To this dimethyl sulfate (0.01 mol) was
added dropwise with stirring. The stirring was continued
for 1 h, the reaction mixture was then poured into ice
water. The solid obtained was filtered, washed with
water, dried under high vacuum and recrystallized from
ethanol/chloroform (75:25) mixture. Yield 88%, mp
124–126 ° C; IR (KBr) cmꢀ1: 1680 (C@O), 1620
5. Experimental
5.1. General
Melting points (mp) were taken in open capillaries on
Thomas Hoover melting point apparatus and are uncor-
rected. The IR spectra were recorded in film or in potas-
1
(C@C); H NMR (CDCl3): d 2.5 (s, 3H, SCH3), 7.0–
8.6 (m, 9H Ar-H); MS (m/z): 268 [M+]; Anal. Calcd
for C15H12N2OS: C, 67.14; H, 4.51; N, 10.44. Found:
C, 67.19; H, 4.53; N, 10.41.
sium bromide disks on
a
Perkin-Elmer 398
spectrometer. The 1H spectra were recorded on a
DPX-300 MHz Bruker FT-NMR spectrometer. The
chemical shifts were reported as parts per million
(d ppm) tetramethylsilane (TMS) as an internal stan-
dard. Mass spectra were obtained on a JEOL-SX-102
instrument using fast atom bombardment (FAB posi-
tive). Elemental analysis was performed on a Perkin-El-
mer 2400 C, H, N analyzer and values were within the
acceptable limits of the calculated values. The progress
of the reaction was monitored on readymade silica gel
plates (Merck) using chloroform/methanol (9:1) as a sol-
vent system. Iodine was used as a developing agent.
Spectral data (IR, NMR and mass spectra) confirmed
the structures of the synthesized compounds and the
purity of these compounds was ascertained by micro-
analysis. Elemental (C, H, and N) analysis indicated
that the calculated and observed values were within
the acceptable limits ( 0.4%). All chemicals and re-
agents were obtained from Aldrich (USA), Lancaster
(UK) or Spectrochem Pvt. Ltd (India) and were used
without further purification.
5.1.3. 2-Hydrazino-3-phenyl-3H-quinazolin-4-one (6).
2-methylsulfanyl-3-phenyl-3H-quinazolin-4-one
The
(5) (0.01 mol) was dissolved in ethanol (25 ml). To this
hydrazine hydrate (0.1 mol) and anhydrous potassium
carbonate (100 mg) were added and refluxed for 22 h.
The reaction mixture was cooled and poured into ice-
water. The solid obtained was filtered, washed with
water, dried under high vacuum and recrystallized
from chloroform/benzene (25:75) mixture. Yield 81%,
mp 158–160 °C; IR (KBr) cmꢀ1
:
3334, 3280
(NHNH2), 1680 (C@O); 1H NMR (CDCl3): d 5.1
(br s, 2H, NH2), 7.0–8.1 (m, 9H, Ar-H), 8.7 (br s,
1H, NH); MS (m/z): 252 [M+]; Anal. Calcd for
C14H12N4O: C, 66.65; H, 4.79; N, 22.21. Found: C,
66.62; H, 4.77; N, 22.26.
5.1.4. General synthetic procedure for compounds (AS1–
AS15). A mixture of 2-hydrazino-3-phenyl-3H-quinazo-
lin-4-one (6) (0.004 mol) and appropriate ketone/alde-
hyde (0.004 mol) in glacial acetic acid was refluxed for
33 h. The reaction mixture was poured into ice water.
The solid obtained was filtered, washed with water,
dried under high vacuum and recrystallized from
ethanol.
5.1.1.
3-Phenyl-2-thioxo-2,3-dihydro-1H-quinazolin-4-
one (4). A solution of aniline (1) (0.02 mol) in dimethyl-
sulfoxide (10 ml) were stirred vigorously. To this was
added carbon disulfide (1.6 ml) and aqueous sodium
hydroxide 1.2 ml (20 M solution) dropwise during
30 min with stirring. Dimethyl sulfate (0.02 mol) was
added gradually keeping the reaction mixture stirring
in freezing mixture for 2 h. The reaction mixture was
then poured into ice water. The solid obtained was fil-
tered, washed with water, dried under high vacuum
and recrystallized from ethanol. Methyl anthranilate
(0.01 mol) and the above-prepared N-phenyl-methyl
dithiocarbamic acid (0.01 mol) were dissolved in etha-
nol (20 ml). To this anhydrous potassium carbonate
(100 mg) was added and refluxed for 18 h. The reaction
mixture was cooled in ice and the solid separated was fil-
tered and purified by dissolving in 10% alcoholic sodium
hydroxide solution (95% alcohol was used for prepara-
tion) and re-precipitated by treating with dilute hydro-
chloric acid. The solid obtained was filtered, washed
with water, dried and recrystallized from ethanol. Yield
86%, mp 305–306 °C; IR (KBr) cmꢀ1: 3220 (NH), 1660
5.1.5.
2-(N0-2-Butylidene-hydrazino)-3-phenyl-3H-qui-
nazolin-4-one (AS1). Yield 73%; mp 239–241 °C; IR :
3310 (NH), 1679 (C@O), 1615 (C@N) cmꢀ1; H NMR
1
(CDCl3): d 1.0–1.1 (q, 2H, CH2CH3), 1.5–1.6 (t, 3H,
CH2CH3), 1.9 (s, 3H, CH3), 7.1–7.9 (m, 9H, Ar-H),
8.5 (br s, 1H, NH); MS (m/z): 306 (M+); Anal. Calcd
for C18H18N4O: C, 70.56; H, 5.92; N, 18.28. Found:
C, 70.59; H, 5.98; N, 18.26.
5.1.6. 2-(N0-3-Pentylidene-hydrazino)-3-phenyl-3H-qui-
nazolin-4-one (AS2). Yield 79%; mp 261–263 °C; IR :
3360 (NH), 1682 (C@O), 1610 (C@N) cmꢀ1; H NMR
1
(CDCl3): d 1.3–1.5 (m, 4H, (CH2CH3)2), 1.8–2.0 (m,
6H, (CH2CH3)2), 7.3–8.1 (m, 9H, Ar-H), 8.7 (br s, 1H,
NH); MS (m/z): 320 (M+); Anal. Calcd for
C19H20N4O: C, 71,22; H, 6.29; N, 17.48. Found: C,
71.26; H, 6.25; N, 16.51.

240
V. Alagarsamy et al. / Bioorg. Med. Chem. 15 (2007) 235–241
5.1.7. 2-(N0-2-Pentylidene-hydrazino)-3-phenyl-3H-qui-
nazolin-4-one (AS3). Yield 73%; mp 210–211 °C; IR:
(M+); Anal. Calcd for C21H15N4OCl: C, 67.29; H,
4.03; N, 14.94. Found: C, 67.22; H, 4.09; N, 14.91.
1
3300 (NH), 1680 (C@O), 1613 (C@N) cmꢀ1; H NMR
(CDCl3): d 1.1–1.2 (t, 2H, CH2CH2CH3), 1.4–1.5 (sext,
2H, CH2CH2CH3), 1.6–1.7 (t, 3H, CH2CH2CH3), 2.1
(s, 3H, CH3), 7.1–7.8 (m, 9H, Ar-H), 8.5 (br s, 1H,
NH); MS (m/z): 320 (M+); Anal. Calcd for
C19H20N4O: C, 71.22; H, 6.29; N, 17.48. Found: C,
71.19; H, 6.31; N, 17.54.
5.1.15. 2-(N0-(2-Nitro-benzylidene-hydrazino))-3-phenyl-
3H-quinazolin-4-one (AS11). Yield 76%; mp 212–
214 °C; IR: 3290 (NH), 1680 (C@O), 1616 (C@N)
1
cmꢀ1; H NMR (CDCl3): d 6.4 (s, 1H, CH), 7.0–8.1
(m, 13H, Ar-H), 8.5–8.6 (br s, 1H, NH); MS (m/z):
385 (M+); Anal. Calcd for C21H15N5O3: C, 65.44; H,
3.92; N, 18.17. Found: C, 65.49; H, 3.96; N, 18.21.
5.1.8.
2-(N0-Cyclohexylidene-hydrazino)-3-phenyl-3H-
quinazolin-4-one (AS4). Yield 76%; mp 223–224 °C; IR:
5.1.16. 2-(N0-(4-Nitro-benzylidene-hydrazino))-3-phenyl-
3H-quinazolin-4-one (AS12). Yield 73%; mp 260–
262 °C; IR: 3310(NH), 1690 (C@O), 1610 (C@N)
1
3260 (NH), 1685 (C@O), 1610 (C@N) cmꢀ1; H NMR
(CDCl3): d 0.9–1.7 (m, 10H, cyclohexanyl), 7.2–7.9 (m,
9H, Ar-H), 8.3 (br s, 1H, NH); MS (m/z): 332(M+);
Anal. Calcd for C20H20N4O: C, 72.29; H, 6.02; N,
16.86. Found: C, 72.31; H, 6.07; N, 16.82.
1
cmꢀ1; H NMR (CDCl3): d 6.5 (s, 1H, CH), 7.3–8.4
(m, 13H, Ar-H), 8.4 (br s, 1H, NH). MS (m/z): 385
(M+); Anal. Calcd for C21H15N5O3: C, 65.44; H, 3.92;
N, 18.17. Found: C, 65.46; H, 3.96; N, 18.24.
5.1.9. 2-(N0-1-Phenylethylidene-hydrazino)-3-phenyl-3H-
quinazolin-4-one (AS5). Yield 72%; mp 255–256 °C; IR:
5.1.17.
2-(N0-(4-Methoxy-benzylidene-hydrazino))-3-
1
3320 (NH), 1690 (C@O), 1616 (C@N) cmꢀ1; H NMR
phenyl-3H-quinazolin-4-one (AS13). Yield 79%; mp
274–276 °C; IR: 3290 (NH), 1680 (C@O), 1616 (C@N)
(CDCl3): d 1.3 (s, 3H, CH3), 7.0–8.1 (m, 14H, Ar-H),
8.5 (br s, 1H, NH); MS (m/z): 354 (M+); Anal. Calcd
for C22H18N4O: C, 74.55; H, 5.11; N, 15.80. Found:
C, 74.58; H, 5.16; N, 15.77.
1
cmꢀ1; H NMR (CDCl3): d 2.5–2.6 (s, 3H, OCH3), 6.3
(s, 1H, CH), 7.1–8.1 (m, 13H, Ar-H), 8.3 (br s, 1H,
NH); MS (m/z): 370 (M+); Anal. Calcd for
C22H18N4O2: C, 71.33; H, 4.89; N, 15.12. Found: C,
71.36; H, 4.95; N, 15.13.
5.1.10.
3H-quinazolin-4-one (AS6). Yield 73%; mp 229–231 °C;
IR: 3310 (NH), 1685 (C@O), 1616 (C@N) cmꢀ1 1H
2-(N0-Phenyl-benzylidene-hydrazino)-3-phenyl-
;
5.1.18. 2-(N0-(2-Methyl-benzylidene-hydrazino))-3-phen-
yl-3H-quinazolin-4-one (AS14). Yield 73%; mp 263–
265 °C; IR: 3260 (NH), 1680 (C@O), 1612 (C@N)
NMR (CDCl3): d 7.2–8.5 (m, 19H, Ar-H), 8.5 (br s,
1H, NH); MS (m/z): 416 (M+); Anal. Calcd for
C27H20N4O: C, 77.86; H, 4.84; N, 13.45. Found: C,
77.88; H, 4.89; N, 13.41.
1
cmꢀ1; H NMR (CDCl3): d 2.1 (s, 3H, CH3), 6.4 (s,
1H, CH), 7.3–8.4 (m, 13H, Ar-H), 8.6 (br s, 1H, NH).
MS (m/z): 354 (M+); Anal. Calcd for C22H18N4O: C,
74.55; H, 5.11; N, 15.80. Found: C, 74.58; H, 5.16; N,
15.76.
5.1.11. 2-(N0-Indolin-2-one-3-yl-idene-hydrazino)-3-phen-
yl-3H-quinazolin-4-one (AS7). Yield 74%; mp 233–
235 °C; IR: 3300 (NH), 1700 (C@O), 1612 (C@N)
1
cmꢀ1; H NMR (CDCl3): d 7.2–8.3 (m, 13H, Ar-H),
5.1.19. 2-(N0-(4-Methyl-benzylidene-hydrazino))-3-phen-
yl-3H-quinazolin-4-one (AS15). Yield 70%; mp 272–
273 °C; IR : 3290 (NH), 1690 (C@O), 1610 (C@N)
8.5 (br s, 1H, NH), 9.3 (br s, 1H, NH); MS (m/z): 381
(M+); Anal. Calcd for C22H15N5O2: C, 69.28; H, 3.96;
N, 18.36. Found: C, 69.21; H, 3.3.94; N, 18.39.
1
cmꢀ1; H NMR (CDCl3): d 2.3 (s, 3H, CH3), 6.3 (s,
3H, CH3), 7.1–8.1 (m, 13H, Ar-H), 8.3 (br s, 1H,
NH); MS (m/z): 354 (M+); Anal. Calcd for
C22H18N4O: C, 74.55; H, 5.11; N, 15.80. Found: C,
74.62; H, 5.13; N, 15.86.
5.1.12. 2-(N0-Benzylidene-hydrazino)-3-phenyl-3H-qui-
nazolin-4-one (AS8). Yield 76%; mp 205–206 °C; IR:
1
3360 (NH), 1690 (C@O), 1615 (C@N) cmꢀ1; H NMR
(CDCl3): d 6.3 (s, 1H, CH), 7.3–8.3 (m, 14H, Ar-H),
8.5 (br s, 1H, NH); MS (m/z): 340 (M+); Anal. Calcd
for C21H16N4O: C, 74.10; H, 4.73; N, 16.46. Found:
C, 74.17; H, 4.75; N, 16.49.
5.2. Pharmacology
The synthesized compounds were evaluated for anal-
gesic, anti-inflammatory, ulcerogenic index and antimi-
crobial activities. The test compounds and the
standard drugs were administered in the form of a
suspension (1% carboxy methyl cellulose as a vehicle)
by oral route of administration for analgesic and anti-
inflammatory but for ulcerogenicity studies by intra-
peritoneally as suspension in 10% v/v Tween 20. Each
group consisted of six animals. The animals were pro-
cured from the Tetrex Biological Center, Madurai, In-
dia, and were maintained in colony cages at 25 2 °C,
relative humidity of 45–55%, under a 12 h light and
dark cycle; they were fed standard animal feed. All
the animals were acclimatized for a week before use.
The Institutional Animal Ethics Committee approved
5.1.13. 2-(N0-(2-Chloro-benzylidene-hydrazino))-3-phen-
yl-3H-quinazolin-4-one (AS9). Yield 74%; mp 247–
249 °C; IR: 3360 (NH), 1685 (C@O), 1616 (C@N)
1
cmꢀ1; H NMR (CDCl3): d 6.5 (s, 1H, CH), 7.0–8.1
(m, 13H, Ar-H), 8.9 (br s, 1H, NH); MS (m/z): 375
(M+); Anal. Calcd for C21H15N4OCl: C, 67.29; H,
4.03; N, 14.94. Found: C, 67.26; H, 4.07; N, 14.99.
5.1.14. 2-(N0-(4-Chloro-benzylidene-hydrazino))-3-phen-
yl-3H-quinazolin-4-one (AS10). Yield 72%; mp 219–
221 °C; IR: 3340 (NH), 1690 (C@O), 1612 (C@N)
1
cmꢀ1; H NMR (CDCl3): d 6.5 (s, 1H, CH), 7.2–8.2
(m, 13H, Ar-H), 8.5 (br s, 1H, NH); MS (m/z): 375

V. Alagarsamy et al. / Bioorg. Med. Chem. 15 (2007) 235–241
241
the protocol adopted for the experimentation of
animals.
Four hours after the ligation, animals were sacrificed.
The stomach was removed and opened along with the
greater curvature. Ulcer index was determined by the
method of Ganguly and Bhatnagar19 and recorded
in Table 3.
5.2.1. Analgesic activity. The analgesic activity was per-
formed by tail-flick technique14,15 using Wistar albino
mice (25–35 g) of either sex selected by random sampling
technique. Diclofenac sodium at a dose level of 10 and
20 mg/kg was administered orally as reference drug for
comparison. The test compounds at two dose levels
(10 and 20 mg/kg) were administered orally. The reac-
tion time was recorded at 30 min, 1, 2 and 3 h after
the treatment, and cut-off time was 10 s. The percent
analgesic activity (PAA) was calculated by the following
formula,
5.2.4. Statistical analysis. Statistical analysis of the bio-
logical activity of the synthesized compounds on ani-
mals was evaluated using a one-way analysis of
variance (ANOVA). In all cases, post hoc compari-
sons of the means of individual groups were per-
formed using Tukey’s test. A significance level of
P < 0.05 denoted significance in all cases. All values
are expressed as means SD (standard deviations).
For statistical analysis we have used GraphPad Prism
3.0 version. (GraphPad Prism 3.0 version, GraphPad
Software, Inc. 11452 El Camino Real, #215, San Die-
go, CA 92130, USA).
ꢀ
ꢁ
T2 ꢀ T 1
10 ꢀ T1
PAA ¼
ꢁ 100
where T1 is the reaction time (s) before treatment and T2
is the reaction time (s) after treatment.
References and notes
5.2.2. Anti-inflammatory activity. Anti-inflammatory
activity was evaluated by carrageenan-induced paw
oedema test in rats.16 Diclofenac sodium 10, 20 mg/kg
was administered as a standard drug for comparison.
The test compounds were administered at two dose lev-
els (10 mg, 20 mg/kg). The paw volumes were measured
using the mercury displacement technique with the help
of a plethysmograph (Model PLYAN; Buxco, USA).
immediately before and 30 min, 1, 2 and 3 h after carra-
geenan injection. The percent inhibition of paw oedema
was calculated using the following formula
1. Vane, J. R.; Botting, R. M. Inflamm. Res. 1998, 47, S78–
S87.
2. Ryn, J. V.; Trummlitz, G.; Pairet, M. Curr. Med. Chem.
2000, 7, 1145–1161.
3. Carter, J. S. Expert Opin. Ther. Pat. 2000, 10, 1011–1020.
4. Beuck, M. Angew. Chem., Int. Ed. 1999, 38, 631–633.
5. Alagarsamy, V.; Revathi, R.; Vijayakumar, S.; Ramseshu,
K. V. Pharmazie 2003, 58, 4–8.
6. Alagarsamy, V.; Thangathirupathy, A.; Mandal, S. C.;
Rajasekaran, S.; Vijayakumar, S.; Revathi, R.; Anburaj,
J.; Arunkumar, S.; Rajesh, S. Indian J. Pharm. Sci. 2006,
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7. Srivastava, B. M.; Bhalla, V. K.; Shankar, T. N. Arzneim.
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Percent inhibition I ¼ 100½1 ꢀ ða ꢀ xÞ=ðb ꢀ yÞꢂ
8. Hitkari, A.; Saxena, M.; Verma, A. K.; Gupta, M.;
Shankar, M. P. Bull. Chim. Farm. 1995, 134, 609–615.
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thirupathy, A.; Amuthalakshmi, S.; Revathi, R. Biol.
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where x is the mean paw volume of rats before the
administration of carrageenan and test compounds or
reference compound (test group), a is the mean paw vol-
ume of rats after the administration of carrageenan in
the test group (drug treated), b is the mean paw volume
of rats after the administration of carrageenan in the
control group and y is the mean paw volume of rats be-
fore the administration of carrageenan in the control
group.
5.2.3. Evaluation of ulcerogenicity index. Ulceration in
rats was induced as described by Goyal et al.17 Albino
rats of Wistar strain weighing 150–200 g of either sex
were divided into various groups each of six animals.
Control group of animals were administered only with
10% v/v Tween 80 suspension intraperitonially. One
group was administered with Aspirin (German Reme-
dies) intraperitoneally in a dose of 20 mg/kg once dai-
ly for three days. The remaining group of animals was
administered with test compounds intraperitoneally in
a dose of 20 mg/kg. On fourth day, pylorus was ligat-
ed as per the method of Shay et al.18 Animals were
fasted for 36 h before the pylorus ligation procedure.
13. Alagarsamy, V.; Muthukumar, V.; Pavalarani, N.; Vasan-
thanathan, P.; Revathi, R. Biol. Pharm. Bull. 2003, 26,
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18. Shay, M.; Komarov, S. A.; Fels, D.; Meranze, D.;
Grunstein, H.; Siplet, H. Gastroenterol 1945, 5, 43–61.
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