Synthesis and pharmacological evaluation of some 3-(4-methylphenyl)-2- substituted amino-3H-quinazolin-4-ones as analgesic and anti-inflammatory agents

Article abstract of DOI:10.1002/ardp.200600189

A variety of 3-(4-methyl phenyl)-2-substituted amino-3H-quinazolin-4-ones were synthesized by reacting the amino group of 2-hydrazino-3-(4-methyl phenyl)-3H-quinazolin-4-one with a variety of aldehydes and ketones. The starting material 2-hydrazino-3-(4-m

Full text of DOI:10.1002/ardp.200600189

Arch. Pharm. Chem. Life Sci. 2007, 340, 41–46
V. Alagarsamy et al.
41
Full Paper
Synthesis and Pharmacological Evaluation of Some 3-(4-
Methylphenyl)-2-substituted amino-3H-quinazolin-4-ones as
Analgesic and Anti-inflammatory Agents
Veerachamy Alagarsamy1, Durairaj Shankar2, Muthuvel Murugan1, Anees Ahmed Siddiqui3,
and Ramadoss Rajesh3
1 Medicinal Chemistry Research Laboratory, Arulmigu Kalasalingam College of Pharmacy, Anand Nagar,
Krishnankovil, India
2 Department of Pharmacy (CARISM), SASTRA Deemed University, Thirumalaisamudram, Thanjavur, India
3 Department of Pharmaceutical Chemistry, Hamdard University; New Delhi, India
A variety of 3-(4-methyl phenyl)-2-substituted amino-3H-quinazolin-4-ones were synthesized by
reacting the amino group of 2-hydrazino-3-(4-methyl phenyl)-3H-quinazolin-4-one with a variety
of aldehydes and ketones. The starting material 2-hydrazino-3-(4-methyl phenyl)-3H-quinazolin-4-
one was synthesized from 4-methyl aniline. The title compounds were investigated for analgesic,
anti-inflammatory, and ulcerogenic index activities. While the test compounds exhibited signifi-
cant activity, compounds A1, A2, and A3 showed more potent analgesic activity and the com-
pound A3 showed more potent anti-inflammatory activity when compared to the reference stan-
dard diclofenac sodium. Interestingly, the test compounds showed only mild ulcerogenic poten-
tial when compared to aspirin.
Keywords: Analgesic / Anti-inflammatory / Quinazoline /
Received: November 8, 2006; accepted: November 21, 2006
DOI 10.1002/ardp.200600189
chemistry research program we found that quinazolines
and condensed quinazolines exhibit potent central ner-
vous system (CNS) activities like analgesic, anti-inflam-
matory [5], and anticonvulsant [6]. Quinazolin-4(3H)-ones
with 2,3-di-substitution is reported to possess significant
analgesic, anti-inflammatory [7, 8], and anticonvulsant
activities [9]. Earlier, we have documented that 2-phenyl-
3-substituted quinazolines [10], 2-methyl-3-substituted
quinazolines [11], 2-methylthio-3-substituted quinazo-
lines [12], 2,3-disubstituted quinazolines [13] exhibited
good analgesic and anti-inflammatory activities. The pre-
sent work is an extension of our ongoing efforts towards
the development and identification of new molecules for
analgesic and anti-inflammatory activities with minimal
gastrointestinal ulceration side effects. With this back-
ground in mind, in the present study, we have synthe-
sized a series of 3-(4-methyl phenyl)-2-substituted amino-
3H-quinazolin-4-ones. The synthesized compounds were
tested for their analgesic, anti-inflammatory, and ulcero-
genic index activities.
Introduction
Nonsteroidal anti-inflammatory drugs (NSAIDs) are com-
monly prescribed for the treatment of acute and chronic
inflammation, pain, and fever. Most of the NSAIDs that
are available on the market are known to inhibit iso-
forms, a constitutive form, COX-1 and an inducible form,
COX-2 to offer a 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]. In our ongoing medicinal
Correspondence: Veerachamy Alagarsamy, Medicinal Chemistry Re-
search Laboratory, Dayananda Sagar College of Pharmacy, Kumaraswa-
my Layout, Bangalore-560 078. India
E-mail: samy_veera@yahoo.com
Fax: +91 4563 289-322
i 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

42
V. Alagarsamy et al.
Arch. Pharm. Chem. Life Sci. 2007, 340, 41–46
Results and discussion
The synthetic route depicted in Scheme 1 outlines the
chemistry part of the present work. The key intermediate
3-(4-methylphenyl)-2-thioxo-2,3-dihydro-1H-quinazolin-4-
one 4 was obtained by reacting 4-methyl aniline 1 with
carbon disulphide and sodium hydroxide in dimethyl
sulphoxide to give sodium dithiocarbamate, which was
methylated with dimethyl sulphate to afford the dithio-
carbamic acid methyl ester 2. Compound 2, on reflux
with methyl anthranilate 3 in ethanol yielded the
desired 3-(4-methylphenyl)-2-thioxo-2,3-dihydro-1H-qui-
nazolin-4-one 4 via a thiourea intermediate in good yield
(75%). The product obtained was cyclic and not an open
chain thiourea 3a. It was confirmed by its low Rf value,
high melting point, and its solubility in sodium hydro-
xide solution. The IR spectrum of 4 shows intense peaks
at 3215 cm–1 for cyclic thio urea (NH), 1680 cm–1 for carbo-
1
nyl (C=O) and 1210 cm-1 for thioxo (C=S) stretching. H-
NMR spectrum of 4 showed singlet at d 1.2–1.3 ppm due
to CH3 group, a multiplet at d 7.2–8.3 ppm for aromatic
(8H) protons and a singlet at d 10.23 ppm indicating the
presence of NH. Elemental analyses confirm the elemen-
tal composition of the molecule. Further, the molecular
ion recorded in the mass spectrum is also in agreement
with the molecular weight of the compound.
The 2-methysulfanyl-3-(4-methylphenyl)-3H-quinazo-
lin-4-one 5 was obtained by dissolving 4 in 2% alcoholic
sodium hydroxide solution and methylation with
dimethyl sulphate under stirring at room temperature.
The IR spectrum of 5 showed disappearance of NH and
C=S stretching signals of cyclic thiourea. It showed a
peak for carbonyl (C=O) stretching at 1679 cm–1. The 1H-
NMR spectrum of compound 5 showed singlets at
d 2.4 ppm and 2.5 ppm due to CH3 and SCH3 respectively,
a multiplet at d 7.1–8.2 ppm was observed for the aro-
matic (8H) protons. Data from the elemental analyses
and molecular ion recorded in the mass spectrum
further confirmed the assigned structure.
Nucleophilic displacement of methylthio group of 5
with hydrazine hydrate was carried out using ethanol as
solvent to afford 2-hydrazino-3-(4-methylphenyl)-3H-qui-
nazolin-4-one 6. The long duration (30 h) of the reaction
required might be due to the presence of the bulky aro-
matic ring at position 3, which might have reduced the
reactivity of the quinazoline ring system at C-2 position.
The formation of 6 was confirmed by the presence of NH
and NH2 signals at 3334–3314 cm–1 in the IR spectrum. It
also showed a peak for carbonyl (C=O) at 1674 cm–1. The
1H-NMR spectrum of the compound 6 showed singlets at
d 2.01 ppm, 5.2 ppm, and 8.72 ppm due to CH3, NH2, and
NH, respectively, a multiplet at d 7.12–8.07 ppm was
Reagents and conditions: (a) DMSO, rt, 30 min; (b) (CH3)2SO4, 5 – 108C, 2 h; (c)
methyl anthranilate (3), K2CO3, ethanol reflux for 18 h; (d) 10% alcoholic NaOH/dil.
HCl, yield 80%; (e) 2% alcoholic NaOH, (CH3)2SO4, rt, 1 h, yield 78%; (f) NH2NH2,
K2CO3, ethanol reflux for 22 h, yield 74%; (g) (R2R1)CO; glacial CH3COOH, reflux,
33 h.
Scheme 1. Synthesis of 2-(1-methylpropylidene)-hydrazino-3-
(4-methyl phenyl)-quinazoline 4(3H)-one and its derivatives from
4-methyl aniline.
observed for the aromatic (8H) protons. Data from the ele-
mental analyses have been found to be in conformity
with the assigned structure. Further the molecular ion
recorded in the mass spectrum is also in agreement with
the molecular weight of the compound.
The title compounds 3-(4-methylphenyl)-2-substituted
amino-3H-quinazolin-4-ones A1-A15 were obtained by the
condensation of amino group of 2-hydrazino-3-(4-methyl
phenyl)-3H-quinazolin-4-one 6 with a variety of aldehydes
and ketones. The formation of title product is indicated
by the disappearance of peak due to NH2 of the starting
material in IR and 1H-NMR spectra of all the compounds
A1–A15. The IR and 1H-NMR spectra of these compounds
showed the presence of peaks due to (N=CR1R2) carbonyl
(C=O), NH, and aryl groups. The mass spectra of the title
compounds are in conformity with the assigned struc-
ture. The mass spectra of these compounds showed mole-
cular ion peaks corresponding to their molecular for-
mula. In mass spectra of compounds A1–A15, a common
i 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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Arch. Pharm. Chem. Life Sci. 2007, 340, 41–46
3-(4-Methylphenyl)-2-subst. amino-3H-quinazolin-4-ones
43
Table 1. Percent analgesic activity of test compounds (tail-flick technique)a.
Compound
Code
Dose
(mg/kg)
Percent Analgesic activity
30 min
1 h
2 h
3 h
A1
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
48 l 1.53*
61 l 1.38***
49 l 1.52**
63 l 1.74***
56 l 1.36*
67 l 1.33***
37 l 1.62*
55 l 1.63**
43 l 1.63*
56 l 1.63**
38 l 1.07*
50 l 1.74*
38 l 1.51*
48 l 1.93*
30 l 1.62*
38 l 1.53*
36 l 1.54*
45 l 1.83*
36 l 1.37*
49 l 1.48*
34 l 1.52*
37 l 1.62*
36 l 1.07*
44 l 1.72*
39 l 1.52*
49 l 1.28*
39 l 1.71*
49 l 1.68*
39 l 1.61*
47 l 1.52*
2 l 0.35
51 l 1.82**
64 l 1.74***
54 l 1.64***
69 l 1.48***
62 l 1.72**
73 € 1.81***
45 l 1.85*
57 l 1.07**
47 l 1.17*
58 l 1.82**
42 l 1.53*
56 l 1.38**
40 l 1.59*
56 l 1.37**
35 l 1.73 *
43 l 1.27*
38 l 1.62*
49 l 1.61*
40 l 1.18*
53 l 1.41*
39 l 1.81 *
48 l 1.83*
40 l 1.38*
45 l 1.81*
39 l 1.61*
54 l 1.71**
45 l 1.05*
53 l 1.53*
42 l 1.63*
50 l 1.04*
6 l 0.49
55 l 1.14**
67 l 1.82***
58 l 1.94***
72 l 1.75***
63 l 1.53**
75 l 1.87***
48 l 1.37*
56 l 1.37**
49 l 1.53*
59 l 1.39**
42 l 1.47*
59 l 1.82**
46 l 1.52*
59 l 1.62**
39 l 1.81*
47 l 1.47*
46 l 1.62*
49 l 1.49*
46 l 1.51*
55 l 1.52*
44 l 1.57*
48 l 1.91*
46 l 1.72*
49 l 1.82**
46 l 1.47*
55 l 1.54*
48 l 1.48*
58 l 1.62**
46 l 1.72*
53 l 1.62*
4 l 0.59
35 l 1.53*
46 l 1.74*
38 l 1.35*
49 l 1.83*
42 l 1.73*
49 l 1.37*
30 l 1.93*
38 l 1.82*
34 l 1.71*
39 l 1.53*
28 l 1.82*
37 l 1.27*
35 l 1.83*
43 l 1.73*
29 l 1.53*
39 l 1.62*
30 l 1.31*
38 l 1.27*
31 l 1.62*
39 l 1.61*
31 l 1.34*
39 l 1.36*
37 l 1.61*
39 l 1.37*
33 l 1.57*
39 l 1.73*
39 l 1.72*
46 l 1.52*
39 l 1.06*
46 l 1.51*
4 l 0.91
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
A12
A13
A14
A15
Control
Diclofenac
10
20
37 l 1.69*
46 l 0.95*
43 l 1.42*
55 l 1.16**
45 l 0.92*
62 l 1.49***
33 l 0.96*
39 l 1.13*
a
Each value represents the mean l SD (n = 6).
Significance levels. * p a 0.5, ** p a 0.01 and *** p a 0.001 as compared with the respective control.
peak at m/z 144 corresponding to quinazolin-4-one moi- tron-withdrawing group at N-3 aryl ring (compounds
ety appeared. Elemental (C, H, N) analyses satisfactorily A8–A12) leads to a further decrease of activity. Com-
confirmed elemental composition and purity of the pound A3 emerged as the most active analgesic agent
synthesized compounds.
and it is more potent when compared to the reference
Test for analgesic activity was performed by the tail- standard diclofenac sodium.
flick technique [14, 15] using Wistar albino mice. The
Anti-inflammatory activity was evaluated by carragee-
results of analgesic activity indicate that all the test com- nan-induced paw oedema test in rats [16]. The anti-
pounds exhibited significant activity (Table 1). Com- inflammatory activity data (Table 2) indicated that all
pound A1 with 2-butylidene substituent showed good the test compounds protected rats from carrageenan-
activity; with the increased lipophilicity (3-pentylidene induced inflammation. The compound A3 showed more
group), A2 showed increase in activity. Replacement of potent anti-inflammatory activity while the compounds
the 3-pentylidene group with its isomer 2-pentylidene A1 and A2 exhibited equipotent anti-inflammatory activ-
group (compound A3) retains the activity. Placement of ity when compared to the reference standard diclofenac
alkyl group and cycloalkyl group (compounds A4 and A5) sodium.
leads to moderate decrease in activity. Placement of aryl
The ulcer index of the test compounds (Table 3) reveals
group at N-3 position (compounds A6, A7 and A13–A15) that the compounds A8–A12 possessing electron-with-
also results in decreasing activity. Placement of an elec- drawing groups exhibited higher ulcer index than the
i 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.archpharm.com

44
V. Alagarsamy et al.
Arch. Pharm. Chem. Life Sci. 2007, 340, 41–46
Table 2. Percent anti-inflammatory activity of test compounds (carrageenan-induced paw oedema test in rats)a.
Compound
Code
Dose
(mg/kg)
Percent Protection
2 h
30 min
1 h
3 h
A1
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
39 l 1.63*
46 l 1.31**
39 l 1.73*
48 l 1.62**
39 l 1.62*
50 l 1.69**
32 l 1.73*
39 l 1.73*
37 l 1.17*
44 l 1.34*
31 l 1.73*
38 l 1.37*
29 l 1.73*
36 l 1.64*
27 l 1.72*
32 l 1.16*
29 l 1.63*
35 l 1.73*
31 l 1.61*
38 l 1.18*
27 l 1.24*
39 l 1.51*
28 l 1.94*
39 l 1.62*
35 l 1.38
40 l 1.12*
31 l 1.38*
45 l 1.47**
31 l 1.61*
41 l 1.84*
5.1 l 0.29
32 l 0.63*
45 l 1.61**
41 l 1.27*
53 l 1.51**
43€ 1.28*
60€ 1.51***
48 l 1.91**
59 l 1.62***
37 l 1.94*
48 l 1.16**
39 l 1.83*
48 l 1.18**
35 l 1.38*
39 l 1.63*
35 l 1.61*
44 l 1.37*
29 l 1.82*
38 l 1.633*
30 l 1.73*
38 l 1.90*
34 l 1.89*
39 l 1.54*
28 l 1.68*
39 l 1.84*
30 l 1.74*
39 l 1.71*
38 l 1.84*
45 l 1.74**
34 l 1.04
45 l 1.72*
52 l 1.78**
48 l 1.83**
63 l 1.73***
53 l 1.72**
63 l 1.73***
41 l 1.81*
50 l 1.38**
42 l 1.29*
49 l 1.46**
38 l 1.62*
41 l 1.84*
39 l 1.29*
48 l 1.91*
33€ 1.43*
39 l 1.28*
33€ 1.48*
39 l 1.72*
38 l 1.37*
42 l 1.74*
32 l 1.73*
43 l 1.93*
37 l 1.06*
45 l 1.95**
38 l 1.03*
49 l 1.18**
39 l 1.37*
49 l 1.63**
36 l 1.83*
47 l 1.73**
5.7 l 0.32
39 l 1.97*
60 l 1.52***
27 l 1.29*
42 l 1.62*
34 l 1.92*
42 l 1.83*
36 l 1.27*
43 l 1.62*
28 l 1.48*
36 l 1.80*
29 l 1.35*
38 l 1.53*
29 l 1.42*
35 l 1.67*
28 l 1.38*
34 l 1.83*
26 l 1.72*
29 l 1.184*
36 l 1.58*
29 l 1.23*
25 l 1.92*
38 l 1.38*
26 l 1.58*
32 l 1.27*
26 l 1.85*
30 l 1.94*
28 l 1.27*
34 l 1.05*
29 l 1.28*
40 l 1.63*
29 l 1.27*
39 l 1.56*
3.2 l 0.93
33 l 0.93*
42 l 1.36**
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
A12
A13
A14
A15
48 l 1.17**
35 l 1.53*
45 l 1.56**
6.1 l 0.27
38 l 1.58*
52 l 0.92***
Control
Diclofenac
10
20
a
Each value represents the mean l SD (n = 6).
Significance levels. * p a 0.5, ** p a 0.01 and *** p a 0.001 as compared with the respective control.
other test compounds. The high ulcer index score for for each pharmacological activity. The most active com-
these compounds may be due to the suppression of the pound of the C-2 phenyl series showed 43% analgesic and
prostaglandin synthesis.
36% anti-inflammatory activity [10], whereas the C-2
methyl series lead molecule showed 50% analgesic and
44% anti-inflammatory activity [11]. Introduction of a sul-
fur atom at C-2 position in the above series, i.e. by placing
a methyl thio group at C-2 position, showed 54% analge-
Conclusions
In our earlier studies [10–15], we observed that the pre- sic and 43% anti-inflammatory activity [12]. The results of
sence of alkyl groups exhibited more analgesic and anti- the analgesic and anti-inflammatory activities of the pre-
inflammatory activities over aryl groups at the N-3 posi- sent series showed that enhancement of activity (61%
tion. Hence, in the C-2 position we also made a substitu- analgesic and 49% anti-inflammatory activity). Interest-
tion in such a way as to increase lipophilicity of the mole- ingly, these compounds showed negligible ulcer index
cule. The placement of such a group enhanced the unlike other non-steroidal anti-inflammatory drugs
analgesic and anti-inflammatory activities. To compare (NSAIDs). Hence this series could be developed as a novel
the increase in activity, we have taken the average of all class of analgesic and anti-inflammatory agents. How-
the readings of reaction time noted for each compound ever, further structural modification is planned to
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Arch. Pharm. Chem. Life Sci. 2007, 340, 41–46
Table 3. Evaluation of ulcerogenicity indexa.
3-(4-Methylphenyl)-2-subst. amino-3H-quinazolin-4-ones
45
sodium hydroxide (1.2 mL, 20 mol solution) drop-wise during
30 min with stirring. Dimethyl sulphate 2.5 g (0.02 mol) was
added gradually keeping the reaction mixture stirring in freez-
ing mixture for 2 h. The reaction mixture was then poured into
ice water. The solid obtained was filtered, washed with water,
dried, and recrystallized from ethanol. Methyl anthranilate
1.51 g (0.01 mol) and the above prepared N-(4-methylphenyl)-
methyl dithiocarbamic acid 1.97 g (0.01 mol), were dissolved in
ethanol (20 mL). To this anhydrous potassium carbonate
(100 mg) was added and refluxed 21 h. The reaction mixture was
cooled in ice and the solid separated was filtered and purified by
dissolving in 10% alcoholic sodium hydroxide solution and
reprecipitated by treating with dilute hydrochloric acid. The
solid obtained was filtered, washed with water, dried, and
recrystallized from ethanol. Yield: 75%, mp 302–3058C; IR (KBr)
cm–1: 3215 (NH), 1680 (C=O), 1210 (C=S); 1H-NMR (CDCl3): d 1.2–
1.3 (s, 3H, CH3), 7.2–8.3 (m, 8H, ArH) and 10.23 (s, 1H, NH); MS
(m/z) 268 [M+]. Anal. Calcd. for C15H12N2OS: C, 67.14; H, 4.51; N,
10.44. Found: C, 67.17; H, 4.53; N, 10.49.
Compound Code
Ulcer index
A1
A2
A3
A4
A5
A6
A7
A8
0.65 l 1.33*
0.57 l 1.20*
0.83 l 1.32*
0.69 l 1.18*
0.62 l 1.06*
0.59 l 1.53*
0.77 l 1.28*
0.95 l 1.54*
0.92 l 1.59
0.99 l 1.21*
0.97 l 1.94*
0.90 l 1.57*
0.72 l 1.31*
0.79 l 1.73*
0.59 l 1.23*
0.15 l 0.32
1.73 l 0.41**
A9
A10
A11
A12
A13
A14
A15
Control
Aspirin
a
Each value represents the mean lSD (n = 6).
Significance levels *p a 0.05 and **p a 0.01 as compared with
the respective control.
2-Methylthio-3-(4-methylphenyl)quinazolin-4(3H)-one 5
The 2-thioxo-3-(4-methylphenyl) quinazolin-4(3H)-one (4) 2.68 g
(0.01 mol) was dissolved in 40 mL of 2% alcoholic sodium hydro-
xide solution. To this, dimethyl sulphate 1.25 g (0.01 mol) was
added drop-wise with stirring. The stirring was continued for
1 h, the reaction was then poured into ice water. The solid
obtained was filtered, washed with water, dried, and recrystal-
lized from ethanol-chloroform (75:25) mixture. Yield: 76%, mp
increase the analgesic and anti-inflammatory activities
with the decreased ulcerogenic index.
1
160–1628C; IR (KBr) cm–1: 1679 (C=O); H-NMR (CDCl3): d 2.4 (s,
3H, CH3), 2.5 (s, 3H, SCH3) and 7.1–8.2 (m, 8H ArH); MS (m/z) 282
[M+]. Anal. Calcd. for C16H14N2OS: C, 68.06; H, 5.00; N, 9.92. Found:
C, 68.09; H, 5.06; N, 9.87.
Experimental
Chemistry
2-Hydrazino-3-(4-methylphenyl)quinazolin-4(3H)-one 6
The 2-methylthio-3-(4-methylphenyl) quinazolin-4(3H)-one (5)
2.82 g (0.01 mol) was dissolved in ethanol (25 mL). To this hydra-
zine hydrate (99%) 5 g (0.1 mol) and anhydrous potassium carbo-
nate (100 mg) was added and refluxed for 30 h. The reaction mix-
ture was cooled and poured into ice water. The solid so obtained
was filtered, washed with water, dried, and recrystallized from
chloroform-benzene (25:75) mixture. Yield: 72%, mp 1708C; IR
Melting points (mp) were taken in open capillaries on Thomas
Hoover melting point apparatus (Philadelphia, PA, USA) and are
uncorrected. Infrared (IR) spectra were recorded in film or in
potassium bromide disks on a Perkin-Elmer 398 spectrometer
(Perkin Elmer). The 1H-NMR spectra were recorded on a DPX-300
MHz Bruker FT-NMR spectrometer (Bruker Biosciences, USA).
The chemical shifts were reported as parts per million (d ppm)
tetramethylsilane (TMS) as an internal standard. Mass spectra
were obtained on a JEOL-SX-102 instrument (JEOL, Tokyo, Japan)
using fast atom bombardment (FAB positive). Elemental analysis
was performed on a Perkin-Elmer 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 solvent
system. Iodine was used as a developing agent. Spectral data (IR,
NMR, and mass spectra) confirmed the structures of the synthe-
sized compounds and the purity of these compounds was ascer-
tained by microanalysis. Elemental (C, H, N) analyses indicated
that the calculated and observed values were within the accepta-
ble limits (l0.4%). All chemicals and reagents were obtained
from Aldrich (USA), Lancaster (UK), or Spectrochem Pvt. Ltd
(India) and were used without further purification.
1
(KBr) cm–1: 3334, 3314 (NHNH2), 1674 (C=O); H-NMR (CDCl3): d
2.01 (s, 3H, CH3), 5.2 (s, 2H, NH2), 7.12–8.07 (m, 8H, ArH), 8.72 (s,
1H, NH); MS (m/z) 266 [M+]. Anal. Calcd. for C15H14N4O: C, 67.65;
H, 5.29; N, 21.04. Found: C, 67.69; H, 5.25; N, 21.07.
2-(N9-2-Butylidene-hydrazino)-3-(4-methylphenyl)-3H-
quinazolin-4-one A1
A mixture of 2-hydrazino-3-(4-methyl phenyl)-3H-quinazolin-4-
one (6) (0.004 mol) and ethylmethyl ketone (0.004 mol) in glacial
acetic acid was refluxed for 33 h. The reaction mixture was
poured into ice water. The solid obtained was recrystallized
from ethanol. Yield: 73%, mp 231–2338C; IR (KBr) cm–1: 3345
(NH), 1670 (C=O), 1615 (C=N); 1H-NMR (CDCl3): d 1.1–1.2 (q, 2H,
CH2CH3), 1.5–1.6 (t, 3H, CH2CH3), 1.9–2.0 (s, 3H, CH3), 2.5–2.6 (s,
3H, CH3), 7.2–8.0 (m, 8H, ArH), 8.5 (brs, 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, 6.30; N, 17.43. Compounds A2–A15 were prepared
by adopting the same procedure.
2-Thioxo-3-(4-methylphenyl)quinazolin-4(3H)-one 4
A solution of 4-methyl aniline (1) 2.14 g (0.02 mol) in dimethyl
sulphoxide (DMSO) (10 mL) was stirred vigorously. To this was
added carbon disulphide (1.6 mL, 0.026 mol) and aqueous
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46
V. Alagarsamy et al.
Arch. Pharm. Chem. Life Sci. 2007, 340, 41–46
was administered with test compounds intraperitoneally in a
dose of 20 mg/kg. On the fourth day, pylorus was ligated as per
the method of Shay et al. [18]. Animals were fasted for 36 h before
the pylorus ligation procedure. 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 Bhatnagar [19] and recorded in
Table 3.
Biological evaluation
The synthesized compounds were evaluated for analgesic, anti-
inflammatory, and antimicrobial activities and the ulcerogenic
index. Student t-test was performed to ascertain the significance
of all the exhibited activities. The test compounds and the stan-
dard drugs were administered in the form of a suspension (1%
carboxy methyl cellulose as a vehicle) by oral route of adminis-
tration for analgesic and anti-inflammatory but for ulcerogeni-
city studies intraperitoneally as suspension in 10% v/v Tween.
Each group consisted of six animals. The animals were procured
from the Tetrex Biological Center, Madurai, India, and were
maintained in colony cages at 25 l 28C, 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 the
protocol adopted for the experimentation of animals.
Statistical analysis
Statistical analysis of the biological activity of the synthesized
compounds on animals was evaluated using a one-way analysis
of variance (ANOVA). In all cases, post-hoc comparisons of the
means of individual groups were performed using Tukey’s test.
A significance level of P a 0.05 denoted significance in all cases.
All values are expressed as mean l SD (standard deviations). For
statistical analysis, we have used GraphPad Prism 3.0 version.
(GraphPad Prism 3.0 version, GraphPad Software, Inc. San Diego,
CA, USA).
Analgesic activity
Test for analgesic activity was performed by Tail-Flick technique
[14, 15] using Wistar albino mice (25–35 gm) of either sex
selected by random sampling technique. Diclofenac sodium at a
dose level of 10 mg/kg and 20 mg/kg was administered orally as
reference drug for comparison. The test compounds at two dose
levels (10, 20 mg/kg) were administered orally. The reaction
time was recorded at 30 min, 1, 2, and 3 h after the treatment,
and cut-off time was 10 sec. The percent analgesic activity (PAA)
was calculated by the following formula:
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ꢁ
T2 ꢀ T1
10 ꢀ T1
PAA ¼
6100
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Evaluation of ulcerogenicity index
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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 intraperitoneally. One group was administered with
Aspirin (German Remedies) intraperitoneally in a dose of 20 mg/
kg once daily for three days. The remaining group of animals
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www.archpharm.com