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

Article abstract of DOI:10.1248/cpb.55.76

A variety of novel 3-(4-methoxyphenyl)-2-substitutedamino-quinazolin-4(3H)- ones were synthesized by reacting the amino group of 2-hydrazino-3-(4- methoxyphenyl)-quinazolin-4(3H)-one with a variety of alkyl and aryl ketones. The starting material 2-hydraz

Full text of DOI:10.1248/cpb.55.76

76
Chem. Pharm. Bull. 55(1) 76—80 (2007)
Vol. 55, No. 1
Synthesis and Pharmacological Evaluation of Some 3-(4-Methoxyphenyl)-
2-substitutedamino-quinazolin-4(3H)-ones as Analgesic and
Anti-inflammatory Agents
Veerachamy ALAGARSAMY* and Sankaranarayanan MURUGESAN
Medicinal Chemistry Research Laboratory, Arulmigu Kalasalingam College of Pharmacy; Anand Nagar, Krishnankovil–
626 190, India. Received August 26, 2006; accepted September 28, 2006
A variety of novel 3-(4-methoxyphenyl)-2-substitutedamino-quinazolin-4(3H)-ones were synthesized by re-
acting the amino group of 2-hydrazino-3-(4-methoxyphenyl)-quinazolin-4(3H)-one with a variety of alkyl and
aryl ketones. The starting material 2-hydrazino-3-(4-methoxyphenyl)-quinazolin-4(3H)-one was synthesized
from 4-methoxyaniline. The title compounds were investigated for analgesic, anti-inflammatory and ulcerogenic
index activities. While the test compounds exhibited significant activity, compounds 2-(1-methylpropylidene)-hy-
drazino-3-(4-methoxyphenyl)-quinazolin-4(3H)-one (A1), 2-(1-ethylpropylidene)-hydrazino-3-(4-methoxyphenyl)-
quinazolin-4(3H)-one (A2) and 2-(1-methylbutylidene)-hydrazino-3-(4-methoxyphenyl)-quinazolin-4(3H)-one
(A3) showed moderately more potent analgesic activity and the compound 2-(1-methylbutylidene)-hydrazino-3-
(4-methoxyphenyl)-quinazolin-4(3H)-one (A3) showed moderately more potent anti-inflammatory activity when
compared to the reference standard diclofenac sodium. Interestingly the test compounds showed only mild ul-
cerogenic potential when compared to aspirin.
Key words quinazoline; analgesic; anti-inflammatory
Nonsteroidal anti-inflammatory drugs (NSAIDs) are com- flux with methyl anthranilate (3) in ethanol yielded the de-
monly prescribed for the treatment of acute and chronic in- sired 3-(4-methoxyphenyl)-2-thioxo-2,3-dihydro-quinazolin-
flammation, pain, and fever. Most of NSAIDs that are avail- 4(1H)-one (4) via the thiourea intermediate in good yield
able in market are known to inhibit isoforms, a constitutive (80%). The product obtained was cyclic and not an open
form, COX-1 and an inducible form, COX-2 to offer thera- chain thiourea 3a. It was confirmed by its low Rf value, high
peutic effect. However long-term clinical usage of NSAIDs melting point and its solubility in sodium hydroxide solution.
are associated with significant side effects of gastrointestinal The IR spectrum of 4 show intense peaks at 3218 cmꢀ1 for
lesions, bleeding, and nephrotoxicity. Therefore the discov- cyclic thio urea (NH), 1680 cmꢀ1 for carbonyl (CꢁO) and
1
ery of new safer anti-inflammatory drugs represents a chal- 1200 cmꢀ1 for thioxo (CꢁS) stretching. H-NMR spectra of
lenging goal for such a research area.1—4) On our going me- 4 showed singlet at d 3.88 ppm due to OCH3 group, a multi-
dicinal chemistry research program we found that quinazo- plet at d 7—8.1 ppm for aromatic (8H) protons and a singlet
lines and condensed quinazolines exhibit potent central at d 10.36 ppm indicating the presence of NH. Data from the
nervous system (CNS) activities like analgesic, anti- elemental analyses have been found to be in conformity with
inflammatory5) and anticonvulsant.6) Quinazolin-4(3H)-ones the assigned structure. Further the molecular ion recorded in
with 2,3-disubstitution is reported to possess significant anal- the mass spectrum is also in agreement with the molecular
gesic, anti-inflammatory7,8) and anticonvulsant activities.9) weight of the compound.
Earlier we have documented 2-phenyl-3-substituted quinazo-
The 2-methysulfanyl-3-(4-methoxyphenyl)-quinazolin-
lines,10) 2-methyl-3-substituted quinazolines,11) 2-methylthio- 4(3H)-one 5 was obtained by dissolving 4 in 2% alcoholic
3-substituted quinazolines,12) 2,3-disubstituted quinazo- sodium hydroxide solution and methylating with dimethyl
lines13) they exhibited good analgesic and anti-inflammatory sulphate with stirring at room temperature. The IR spectra of
activities. The present work is an extension of our ongoing 5 showed disappearance of NH and CꢁS stretching signals
efforts towards the development and identification of new of cyclic thiourea. It showed a peak for carbonyl (CꢁO)
molecules for analgesic and anti-inflammatory activities with stretching at 1683 cmꢀ1. The H-NMR spectra of compound
1
minimal gastrointestinal ulceration side effects. With this 5 showed singlets at d 2.5 ppm and 3.87 ppm due to SCH3
background in the present study we have synthesized a and OCH3 respectively, a multiplet at d 7.0—8.26 ppm was
series of 3-(4-methoxyphenyl)-2-substitutedamino-quinazo- observed for aromatic (8H) protons. Data from the elemental
lin-4(3H)-one. The synthesized compounds were tested for analyses and molecular ion recorded in the mass spectra fur-
their analgesic, anti-inflammatory and ulcerogenic index ac- ther confirmed the assigned structure.
tivities.
Nucleophilic displacement of methylthio group of 5 with
hydrazine hydrate was carried out using ethanol as solvent to
afford 2-hydrazino-3-(4-methoxyphenyl)-quinazolin-4(3H)-
Chemistry
The key intermediate 3-(4-methoxyphenyl)-2-thioxo-2,3- one 6. The long duration of reaction (30 h) required might be
dihydro-quinazolin-4(1H)-one 4 was obtained by reacting 4- due to the presence of bulky aromatic ring at the N-3 posi-
methoxyaniline (1) with carbon disulphide and sodium hy- tion, which might have reduced the reactivity of quinazoline
droxide in dimethyl sulphoxide to give sodium dithiocarba- ring system at C-2 position. The formation of 6 was con-
mate, which was methylated with dimethyl sulphate to afford firmed by the presence of NH and NH2 signals at 3350—
the dithiocarbamic acid methyl ester (2). Compound 2 on re- 3320 cmꢀ1 in the IR spectrum. It also showed a peak for car-
∗ To whom correspondence should be addressed. e-mail: samy_veera@yahoo.com
© 2007 Pharmaceutical Society of Japan

January 2007
77
Table 1. Percent Analgesic Activity of Test Compounds (Tail-Flick Tech-
nique)
Percent analgesic activity
Compound
code
Dose
(mg/kg)
30 min
1 h
2 h
3 h
A1
A2
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
45ꢂ1.76*
47ꢂ1.93*
52ꢂ1.27**
32ꢂ1.81*
59ꢂ1.69*** 63ꢂ1.83*** 64ꢂ1.19*** 44ꢂ1.36*
52ꢂ1.68** 57ꢂ1.94** 59ꢂ1.37*** 43ꢂ1.38*
65ꢂ1.47*** 70ꢂ1.81*** 73ꢂ1.94*** 48ꢂ1.04*
A3
46ꢂ1.92*
59ꢂ1.73*** 66ꢂ1.82*** 68ꢂ1.81*** 46ꢂ1.72*
35ꢂ1.05* 42ꢂ1.83* 47ꢂ160*
51ꢂ1.37** 54ꢂ1.20** 55ꢂ1.38**
39ꢂ1.61* 46ꢂ1.83* 48ꢂ1.47*
52ꢂ1.03** 55ꢂ1.82** 56ꢂ1.91**
39ꢂ1.03* 41ꢂ1.44*
54ꢂ1.93** 56ꢂ1.87**
39ꢂ1.73* 45ꢂ1.62*
54ꢂ1.24** 57ꢂ1.36**
49ꢂ1.06*
53ꢂ1.94**
35ꢂ1.17*
A4
28ꢂ1.04*
36ꢂ1.29*
31ꢂ1.71*
38ꢂ1.73*
29ꢂ1.92*
34ꢂ1.05*
33ꢂ1.38*
38ꢂ1.03*
28ꢂ1.62*
38ꢂ1.81*
29ꢂ1.37*
33ꢂ1.72*
32ꢂ1.91*
36ꢂ1.95*
29ꢂ1.69*
35ꢂ1.54*
33ꢂ1.07*
38ꢂ1.24*
31ꢂ1.26*
38ꢂ1.84*
34ꢂ1.65*
41ꢂ1.76*
30ꢂ1.42*
38ꢂ1.60*
4ꢂ0.91
A5
A6
37ꢂ1.98*
48ꢂ1.64*
36ꢂ1.01*
47ꢂ1.61*
27ꢂ1.41*
35ꢂ1.93*
34ꢂ1.15*
43ꢂ1.28*
33ꢂ1.08*
45ꢂ1.85*
32ꢂ1.42*
35ꢂ1.91*
35ꢂ1.63*
41ꢂ1.52*
37ꢂ1.42*
48ꢂ1.08*
38ꢂ1.08*
47ꢂ1.45*
36ꢂ1.42*
42ꢂ1.37*
2ꢂ0.35
A7
A8
32ꢂ1.92*
40ꢂ1.38*
37ꢂ1.85*
47ꢂ1.94*
37ꢂ1.24*
49ꢂ1.74*
36ꢂ1.71*
46ꢂ1.85*
39ꢂ1.79*
44ꢂ1.96*
38ꢂ1.73*
36ꢂ1.71*
44ꢂ1.15*
41ꢂ1.22*
47ꢂ1.81*
42ꢂ1.74*
53ꢂ1.79*
40ꢂ195*
49ꢂ1.47*
44ꢂ1.54*
48ꢂ1.64**
43ꢂ1.95*
A9
A10
A11
A12
A13
A14
A15
51ꢂ1.76** 53ꢂ1.93*
42ꢂ1.94*
49ꢂ1.16*
38ꢂ1.95*
45ꢂ1.18*
6ꢂ0.49
43ꢂ1.54*
54ꢂ1.25**
43ꢂ1.83*
49ꢂ1.46*
4ꢂ0.59
Control
Diclofenac
10
20
37ꢂ1.69*
46ꢂ0.95*
43ꢂ1.42*
45ꢂ0.92*
33ꢂ0.96*
55ꢂ1.16** 62ꢂ1.49*** 39ꢂ1.13*
Reagents and conditions: (a) DMSO, rt, 30 min; (b) (CH3)2SO4, 5—10 °C, 2 h;
(c) methyl anthranilate (3), K2CO3, ethanol reflux for 21 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; gla.CH3COOH re-
flux, 33 h.
Each value represents the meanꢂS.D. (nꢁ6). Significance levels ∗ pꢃ0.5, ∗∗ pꢃ0.01
and ∗∗∗ pꢃ0.001 as compared with the respective control.
Results and Discussion
Chart 1. Synthesis of 2-(1-Methylpropylidene)-hydrazino-3-(4-methoxy-
phenyl)-quinazolin-4(3H)-one and Its Derivatives from 4-Methoxyaniline
Test for analgesic activity was performed by tail-flick tech-
nique14,15) using Wistar albino mice. The results of analgesic
activity indicate that test compounds exhibited moderate
bonyl (CꢁO) at 1674 cmꢀ1. The H-NMR spectra of the analgesic activity at 30 min of reaction time; the activity in-
compound 6 showed singlets at d 3.79 ppm, 4.95 ppm and creased at 1 h and it reached to peak level at 2 h. Declining in
8.56 ppm due to OCH3, NH2 and NH respectively, a multiplet activity was observed at 3 h (Table 1). Compound A1 with 1-
at d 6.82—8.06 ppm was observed for aromatic (8H) pro- methylpropylidene substituent showed good activity; with the
tons. Data from the elemental analyses have been found to be increased lipophilicity (1-ethylpropylidene group, compound
in conformity with the assigned structure. Further the molec- A2) showed increase in activity. Replacement of 1-ethyl-
ular ion recorded in the mass spectra is also in agreement propylidene group with its isomer 2-pentylidene group (com-
1
with the molecular weight of the compound.
pound A3) retains the activity. Replacement of an alkyl chain
The title compounds 3-(4-methoxyphenyl)-2-substituted- at the 2-position with a cycloalkyl group and an aralkyl
amino-quinazolin-4(3H)-ones A1—A15 were obtained by group (compounds A4 and A5 respectively) leads to moder-
the condensation of amino group of 2-hydrazino-3-(4- ate decrease in activity. Placement of aryl group at the N-3
methoxy phenyl)-quinazolin-4(3H)-one (6) with a variety of position (compounds A6, A7 and A13—A15) also results in
alkyl and aryl ketones. The formation of title product is indi- decreasing activity. Placement of electron withdrawing group
cated by the disappearance of peak due to NH2 of the starting at N-3 aryl ring (compounds A8—A12) leads to further
1
material in IR and H-NMR spectrum of all the compounds decrease of activity. Compound 2-(1-ethylpropylidene)-
1
A1—A15. The IR and H-NMR spectrum of these com- hydrazino-3-(4-methoxyphenyl)-quinazolin-4(3H)-one (A2)
pounds showed the presence of peaks due to (NꢁCR1R2) car- emerged as the most active analgesic agent and it is more po-
bonyl (CꢁO), NH and Aryl groups. The mass spectra of the tent when compared to the reference standard diclofenac
title compounds are in confirmity with the assigned structure. sodium.
The mass spectra of these compounds showed molecular ion
Anti-inflammatory activity was evaluated by carrageenan-
peaks corresponding to their molecular formulae. A common induced paw oedema test in rats.16) The anti-inflammatory
peak at m/z 144 corresponding to quinazolin-4-one moiety activity data (Table 2) indicated that all the test compounds
appeared in all mass spectra of compounds A1—A15. Ele- protected rats from carrageenan-induced inflammation mod-
mental (C, H, N) analysis satisfactorily confirmed elemental erately at 30 min of reaction time; the activity increased at
composition and purity of the synthesized compounds.
1 h and it reached to peak level at 2 h. Declining in activity

78
Vol. 55, No. 1
Table 2. Percent Anti-inflammatory Activity of Test Compounds (Car- Table 3. Evaluation of Ulcerogenicity Index
rageenan-Induced Paw Oedema Test in Rats)
Compd. code
Ulcer index
Percent protection
Compound
code
Dose
(mg/kg)
A1
A2
A3
A4
A5
A6
A7
A8
A9
0.63ꢂ1.51*
0.57ꢂ1.37*
0.56ꢂ1.04*
0.74ꢂ1.39*
0.72ꢂ1.32*
0.74ꢂ1.41*
0.81ꢂ1.72*
0.91ꢂ1.05*
0.96ꢂ1.64
0.94ꢂ1.65*
0.92ꢂ1.47*
0.95ꢂ1.59*
0.66ꢂ1.07*
0.88ꢂ1.27*
0.69ꢂ1.36*
1.05ꢂ0.32
30 min
1 h
2 h
3 h
A1
A2
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
35ꢂ1.15*
41ꢂ1.94*
37ꢂ1.93*
38ꢂ1.73*
46ꢂ1.26** 49ꢂ1.42**
39ꢂ1.37* 43ꢂ1.05*
40ꢂ1.81*
25ꢂ1.54*
38ꢂ1.31*
30ꢂ1.82*
44ꢂ1.90** 57ꢂ1.47*** 59ꢂ1.52*** 38ꢂ1.26*
37ꢂ1.17* 45ꢂ1.42* 49ꢂ1.83* 32ꢂ1.08*
48ꢂ1.19** 60ꢂ1.63*** 65ꢂ1.45*** 40ꢂ1.38*
A3
A4
30ꢂ1.94*
38ꢂ1.51*
34ꢂ1.18*
41ꢂ1.26*
29ꢂ1.15*
34ꢂ1.36*
27ꢂ1.84*
33ꢂ1.25*
24ꢂ1.41*
29ꢂ1.82*
28ꢂ1.23*
31ꢂ1.05*
29ꢂ1.73*
36ꢂ1.05*
24ꢂ1.74*
38ꢂ1.27*
26ꢂ1.18*
36ꢂ1.48*
32ꢂ1.72*
38ꢂ1.54*
29ꢂ1.71*
41ꢂ1.71*
29ꢂ1.05*
38ꢂ1.54*
5.1ꢂ0.29
32ꢂ0.63*
36ꢂ1.42*
46ꢂ1.94*
37ꢂ1.37*
43ꢂ1.37*
32ꢂ1.29*
37ꢂ1.15*
34ꢂ1.27*
42ꢂ1.47*
27ꢂ1.83*
36ꢂ1.63*
26ꢂ1.15*
34ꢂ1.24*
32ꢂ1.06*
37ꢂ1.73*
29ꢂ1.32*
38ꢂ1.93*
29ꢂ1.23*
38ꢂ1.92*
34ꢂ1.37*
41ꢂ1.51*
36ꢂ1.83
39ꢂ1.63*
46ꢂ1.48*
39ꢂ1.19*
46ꢂ1.26**
35ꢂ1.16*
38ꢂ1.71*
38ꢂ1.06*
45ꢂ1.28*
29ꢂ1.52*
32ꢂ1.85*
32ꢂ1.26*
34ꢂ1.25*
36ꢂ1.93*
39ꢂ1.39*
33ꢂ1.85*
42ꢂ1.85*
34ꢂ1.93*
42ꢂ1.61*
37ꢂ1.93*
44ꢂ1.62*
36ꢂ1.54*
26ꢂ1.46*
31ꢂ1.63*
28ꢂ1.83*
33ꢂ1.45*
26ꢂ1.83*
33ꢂ1.15*
26ꢂ1.37*
31ꢂ1.93*
23ꢂ1.73*
28ꢂ1.14*
24ꢂ1.93*
30ꢂ1.93*
23ꢂ1.18*
34ꢂ1.53*
23ꢂ1.39*
30ꢂ1.27*
24ꢂ1.91*
31ꢂ1.83*
29ꢂ1.28*
33ꢂ1.93*
27ꢂ1.42*
37ꢂ1.62*
28ꢂ1.39*
36ꢂ1.63*
3.2ꢂ0.93
33ꢂ0.93*
A5
A10
A11
A12
A13
A14
A15
Control
Diclofenac
Aspirin
A6
A7
A8
A9
1.65ꢂ0.59**
1.73ꢂ0.41**
A10
A11
A12
A13
A14
A15
Dose 20 mg for test compounds, diclofenac and aspirin. Each value represents the
meanꢂS.D. (nꢁ6). Significance levels ∗ pꢃ0.05 and ∗∗ pꢃ0.01 as compared with the
respective control.
41ꢂ1.36** 42ꢂ1.81*
30ꢂ1.41*
41ꢂ1.62*
6.1ꢂ0.27
38ꢂ1.58*
32ꢂ1.54*
45ꢂ1.61*
5.7ꢂ0.32
39ꢂ1.97*
Control
Diclofenac
10
20
45ꢂ1.61** 52ꢂ0.92*** 60ꢂ1.52*** 42ꢂ1.36**
Each value represents the meanꢂS.D. (nꢁ6). Significance levels ∗ pꢃ0.5, ∗∗ pꢃ0.01
and ∗∗∗ pꢃ0.001 as compared with the respective control.
was observed at 3 h. The compound 2-(1-methylbutylidene)-
hydrazino-3-(4-methoxyphenyl)-quinazolin-4(3H)-one (A3)
showed moderately more potent anti-inflammatory activity
when compared to the reference standard diclofenac sodi-
Fig. 1
um. The compound 2-(1-ethylpropylidene)-hydrazino-3-(4- Conclusions
methoxyphenyl)-quinazolin-4(3H)-one (A2) showed equipo-
In our earlier studies10—13) we observed that the presence
tent anti-inflammatory activity when compared to the refer- of alkyl groups exhibited more analgesic and anti-inflamma-
ence standard diclofenac sodium.
tory activities over aryl groups at the N-3 position. Hence in
The ulcer index of the test compounds (Table 3) reveal that the C-2 position also we made a substitution in such a way to
the compounds with open chain aliphatic substituents (com- increase lipophilicity of the molecule. The placement of such
pounds A1—A3) showed negligible ulcer index, whereas a group enhanced the analgesic and anti-inflammatory activi-
aryl substituents (compounds A5—A7 and A13—A15) ex- ties. The most active compound of the C-2 phenyl series 1-
hibited little increase in ulcer index and the aryl substituents diethyl-3-(2-phenyl quinazolin-3-yl-4(3H)-one) thiourea (7)
containing electron withdrawing groups (compounds A8— (Fig. 1) showed 44% and 58% analgesic and 38% and 53%
A12) exhibited higher ulcer index over other test compounds. anti-inflammatory activity at the dose of 10 and 20 mg/kg re-
When compared to the reference standards aspirin (ulcer spectively, at the reaction time of 2 h.10) Whereas the C-2
index 1.73ꢂ0.41) and diclofenac (ulcer index 1.65ꢂ0.59) methyl series lead molecule 1-pyrrolidinyl-3-(2-methyl
the test compounds exhibited about 35 to 50% of the ulcer quinazolin-3-yl-4(3H)-one) thiourea (8) (Fig. 1) exhibited
index of reference standards. Compounds 2-(1-ethylpropyli- 50% and 65% analgesic and 44% and 60% anti-inflamma-
dene)-hydrazino-3-(4-methoxyphenyl)-quinazolin-4(3H)-one tory activity at the dose of 10 and 20 mg/kg respectively at
(A2) and 2-(1-methylbutylidene)-hydrazino-3-(4-methoxy- the reaction time of 2 h.11) Introduction of sulphur atom at C-
phenyl)-quinazolin-4(3H)-one (A3) exhibited least ulcer 2 position in the above series i.e. by placing methylthio
index (0.57ꢂ1.37 and 0.56ꢂ1.04 respectively) among the group at C-2 position12) compound 1-diethyl-3-(2-methylthio
test compounds which is about one third of the ulcer index of quinazolin-3-yl-4(3H)-one) thiourea (9) (Fig. 1) exhibited
reference standards aspirin and diclofenac. The compound 2- 56%, 67% analgesic activity, 40% and 62% anti-inflamma-
(Nꢄ-(4-chloro-benzylidene-hydrazino)-3-(4-methoxyphenyl)- tory activity at 10 and 20 mg/kg respectively at the reaction
quinazolin-4(3H)-one (A9) showed the highest ulcer index time of 2 h. The results of the analgesic and anti-inflamma-
(0.96ꢂ1.64) among the test compounds which is about 50% tory activities of the present series showed that moderate en-
of the ulcer index of aspirin and diclofenac.
hancement of activity. The compound A2 exhibited 59% and

January 2007
79
2-(1-Methylpropylidene)-hydrazino-3-(4-methoxyphenyl)-quinazolin-
4(3H)-one (A1) A mixture of 2-hydrazino-3-(4-methoxyphenyl)-quina-
zolin-4(3H)-one (6) (1.128 g, 0.288 g, 0.004 mol) and ethylmethyl ketone
(0.004 mol) in glacial acetic acid was refluxed for 36 h. The reaction mixture
was poured into ice water. The solid obtained was recrystallized from
73% analgesic activity at 10 and 20 mg/kg dose level respec-
tively at the reaction time of 2 h. The compound A3 showed
49% and 65% anti-inflammatory activity at the dose of 10
and 20 mg/kg respectively at the reaction of 2 h. Interestingly
these compounds showed 35% of ulcer index of the reference ethanol. Yieldꢁ76%, mp 218—219 °C. IR (KBr) cmꢀ1: 3356 (NH), 1673
(CꢁO), 1610 (CꢁN). 1H-NMR (CDCl3) d ppm: 1.2—1.3 (q, 2H, CH2CH3),
NSAID’s aspirin and diclofenac. Hence this series could be
developed as a novel class of analgesic and anti-inflamma-
tory agents. However further structural modification is
1.6—1.7 (t, 3H, CH2CH3), 2.0—2.1 (s, 3H, CH3), 3.2—3.3 (s, 3H, OCH3),
7.0—7.7 (m, 8H, ArH), 8.2 (br s, 1H, NH). MS (m/z): 336 (Mꢅ). Anal.
Calcd for C19H20N4O2: C, 67.83; H, 5.99; N, 16.65. Found: C, 67.86; H,
planned to increase the analgesic and anti-inflammatory ac-
tivities with the decreased ulcerogenic index.
5.5.97; N, 16.61.
2-(1-Ethylpropylidene)-hydrazino-3-(4-methoxyphenyl)-quinazolin-
4(3H)-one (A2) Compound A2 was prepared by adopting the same proce-
Experimental
dure as for A1 and obtained in 73% yield, mp 243—245 °C. IR (KBr) cmꢀ1
:
Melting points (mp) were taken in open capillaries on Thomas Hoover 3330 (NH), 1686 (CꢁO), 1616 (CꢁN). 1H-NMR (CDCl3) d ppm: 1.0—1.2
melting point apparatus and are uncorrected. Infrared (IR) spectra were (m, 4H, (CH2CH3)2), 1.5—1.7 (m, 6H, (CH2CH3)2), 3.0 (s, 3H, OCH3),
recorded on an FT-IR Perkin-Elmer spectrometer. The 1H-NMR spectra were 7.5—8.2 (m, 8H, ArH), 8.4 (br s, 1H, NH). MS (m/z): 350 (Mꢅ). Anal.
recorded on a DPX-300 MHz Bruker FT-NMR spectrometer. The chemical Calcd for C20H22N4O2: C, 68.55; H, 6.32; N, 15.98. Found: C, 68.60; H,
shifts were reported as parts per million (d ppm) tetramethylsilane (TMS) as 6.36; N, 15.95.
an internal standard. Mass spectra were obtained on a JEOL-SX-102 instru-
ment using fast atom bombardment (FAB positive). Elemental analysis was 4(3H)-one (A3) Compound A3 was prepared by adopting the same proce-
performed on a Perkin-Elmer 2400 C, H, N analyzer and values were within dure as for A1 and obtained in 77% yield, mp 251—252 °C. IR (KBr) cmꢀ1
the acceptable limits of the calculated values. The progress of the reaction 3260 (NH), 1687 (CꢁO), 1618 (CꢁN). 1H-NMR (CDCl3) d ppm: 1.3—1.4
was monitored on readymade silica gel plates (Merck) using chloroform–
(t, 2H, CH2CH2CH3), 1.7—1.8 (sext, 2H, CH2CH2CH3), 2.3—2.4 (t, 3H,
2-(1-Methylbutylidene)-hydrazino-3-(4-methoxyphenyl)-quinazolin-
:
methanol (9 : 1) as a solvent system. Iodine was used as a developing agent. CH2CH2CH3), 2.8 (s, 3H, CH3), 3.5 (s, 3H, OCH3), 7.2—7.9 (m, 9H, ArH),
Spectral data (IR, NMR and mass spectra) confirmed the structures of the
synthesized compounds and the purity of these compounds was ascertained
by microanalysis. Elemental (C, H, N) analysis indicated that the calculated
8.2 (br s, 1H, NH). MS (m/z): 350 (Mꢅ). Anal. Calcd for C20H22N4O2: C,
68.55; H, 6.32; N, 15.98. Found: C, 68.52; H, 6.37; N, 17.96.
2-(Nꢀ-Cyclohexylidene-hydrazino)-3-(4-methoxyphenyl)-quinazolin-
and observed values were within the acceptable limits (ꢂ0.4%). All chemi- 4(3H)-one (A4) Compound A4 was prepared by adopting the same proce-
cals and reagents were obtained from Aldrich (U.S.A.), Lancaster (U.K.) or dure as for A1 and obtained in 77% yield, mp 247—248 °C. IR (KBr) cmꢀ1
Spectrochem Pvt.Ltd (India) and were used without further purification.
:
3230 (NH), 1690 (CꢁO), 1616 (CꢁN). 1H-NMR (CDCl3) d ppm: 1.1—1.9
3-(4-Methoxyphenyl)-2-thioxo-2,3-dihydro-quinazolin-4(1H)-one (4)
(m, 10H, cyclohexyl), 3.3 (s, 3H, OCH3),7.1—7.8 (m, 8H, ArH), 8.5 (br s,
A solution of 4-methoxyaniline 1 (2.46 g, 0.02 mol) in dimethyl sulfoxide 1H, NH). MS (m/z): 362 (Mꢅ). Anal. Calcd for C21H22N4O2: C, 69.59; H,
(10 ml) was stirred vigorously. To this was added carbon disulphide (1.98 g, 6.11; N, 15.45. Found: C, 69.51; H, 6.08; N, 15.48.
0.026 mol) and 20 M aqueous sodium hydroxide solution (1.2 ml) drop wise
during 30 min with stirring. Dimethyl sulphate (2.52 g, 0.02 mol) was added
2-(Nꢀ-1-Phenylethylidene-hydrazino)-3-(4-methoxyphenyl)-quinazo-
lin-4(3H)-one (A5) Compound A5 was prepared by adopting the same
gradually keeping the reaction mixture stirring in freezing mixture for 2 h. procedure as for A1 and obtained in 77% yield, mp 273—274 °C. IR (KBr)
The reaction mixture was then poured into ice water. The solid obtained was cmꢀ1: 3290 (NH), 1686 (CꢁO), 1619 (CꢁN). 1H-NMR (CDCl3) d ppm: 1.1
filtered, washed with water, dried and recrystallized from ethanol. Methyl (s, 3H, CH3), 3.4 (s, 3H, OCH3), 7.3—8.2 (m, 13H, ArH), 8.6 (br s, 1H,
anthranilate (1.51 g, 0.01mol) and the above prepared N-(4-methoxyphenyl)- NH). MS (m/z): 384 (Mꢅ). Anal. Calcd for C23H20N4O2: C, 71.85; H, 5.24;
methyl dithiocarbamic acid (2.13 g, 0.01 mol), were dissolved in ethanol N, 14.57. Found: C, 71.89; H, 5.26; N, 14.62.
(20 ml). To this anhydrous potassium carbonate (100 mg) was added and re-
2-(Nꢀ-2-Oxo-indolin-2-one-3-yl-idene-hydrazino)-3-(4-methoxy-
fluxed for 21 h. The reaction mixture was cooled in ice and the solid sepa- phenyl)-quinazolin-4(3H)-one (A6) Compound A6 was prepared by
rated was filtered and purified by dissolving in 10% alcoholic sodium hy- adopting the same procedure as for A1 and obtained in 79% yield, mp 224—
1
droxide solution and reprecipitated by treating with dilute hydrochloric acid. 225 °C. IR (KBr) cmꢀ1: 3280 (NH), 1680 (CꢁO), 1615 (CꢁN). H-NMR
The solid obtained was filtered, washed with water, dried and recrystallized (CDCl3) d ppm: 3.1 (s, 3H, OCH3), 7.0—8.2 (m, 12H, ArH), 8.4 (br s, 1H,
from ethanol. Yieldꢁ80%, mp 296—300 °C. IR (KBr) cmꢀ1: 3218 (NH),
NH), 9.0 (br s, 1H, NH). MS (m/z): 411 (Mꢅ). Anal. Calcd for C23H17N4O3:
C, 67.14; H, 4.16; N, 13.61. Found: C, 67.17; H, 4.18; N, 13.64.
2-(Nꢀ-Benzylidene-hydrazino)-3-(4-methoxyphenyl)-quinazolin-
1
1680 (CꢁO), 1593 (CꢁC), 1200 (CꢁS); H-NMR (CDCl3) d (ppm): 3.88
(s, 3H, OCH3), 7.0—8.1 (m, 8H, ArH), 10.36 (s, 1H, NH); MS (m/z): 284
(Mꢅ). Anal. Calcd for C15H12N2O2S: C, 63.36; H, 4.25; N, 9.85. Found: C, 4(3H)-one (A7) Compound A7 was prepared by adopting the same proce-
63.29; H, 4.21; N, 9.91.
dure as for A1 and obtained in 73% yield, mp 243—245 °C. IR (KBr) cmꢀ1
:
2-Methylsulfanyl-3-(4-methoxyphenyl)-quinazolin-4(3H)-one (5) The
3-(4-methoxyphenyl)-2-thioxo-2,3-dihydro-quinazolin-4(1H)-one 4 (2.84 g,
3310 (NH), 1686 (CꢁO), 1610 (CꢁN). 1H-NMR (CDCl3) d ppm: 3.3 (s,
3H, OCH3), 6.5 (s, 1H, CH), 7.1—8.2 (m, 13H, ArH), 8.7 (br s, 1H, NH).
0.01 mol) was dissolved in 40 ml of 2% alcoholic sodium hydroxide solu- MS (m/z): 370 (Mꢅ). Anal. Calcd for C22H18N4O2: C, 71.33; H, 4.89; N,
tion. To this dimethyl sulphate (1.26 g, 0.01 mol) was added drop wise with 15.12. Found: C, 71.36; H, 4.86; N, 15.14.
stirring. The stirring was continued for 1 h, the reaction mixture was then
2-(Nꢀ-(2-Chloro-benzylidene-hydrazino))-3-(4-methoxyphenyl)-quina-
poured into ice water. The solid obtained was filtered, washed with water, zolin-4(3H)-one (A8) Compound A8 was prepared by adopting the same
dried and recrystallized from ethanol–chloroform (75 : 25) mixture.
procedure as for A1 and obtained in 79% yield, mp 263—264 °C. IR (KBr)
Yieldꢁ78%, mp 142—145 °C; IR (KBr) cmꢀ1: 1683 (CꢁO), 1610 (CꢁC); cmꢀ1: 3320 (NH), 1683 (CꢁO), 1610 (CꢁN). 1H-NMR (CDCl3) d ppm: 3.2
1H-NMR (CDCl3) d (ppm): 2.5 (s, 3H, SCH3), 3.87 (s, 3H, OCH3), 7.0— (s, 3H, OCH3), 6.3 (s, 1H, CH), 7.1—8.3 (m, 12H, ArH), 8.6 (br s, 1H, NH).
8.26 (m, 8H ArH); MS (m/z): 298 (Mꢅ); Anal. Calcd for C16H14N2O2S: C,
64.41; H, 4.72; N, 9.38. Found: C, 64.53; H, 4.67; N, 9.45.
MS (m/z): 405 (Mꢅ). Anal. Calcd for C22H17N4O2Cl: C, 65.27; H, 4.23; N,
13.84. Found: C, 65.21; H, 4.26; N, 13.88.
2-Hydrazino-3-(4-methoxyphenyl)-quinazolin-4(3H)-one (6) The 2-
2-(Nꢀ-(4-Chloro-benzylidene-hydrazino)-3-(4-methoxyphenyl)-quina-
methylsulfanyl-3-(4-methoxyphenyl)-quinazolin-4(3H)-one 5 (2.98 g, 0.01 zolin-4(3H)-one (A9) Compound A9 was prepared by adopting the same
mol) was dissolved in ethanol (25 ml). To this hydrazine hydrate (99%) (5 g, procedure as for A1 and obtained in 78% yield, mp 260—261 °C. IR (KBr)
0.1 mol) and anhydrous potassium carbonate (100 mg) was added and re-
cmꢀ1: 3270 (NH), 1687 (CꢁO), 1616 (CꢁN). 1H-NMR (CDCl3) d ppm: 3.4
fluxed for 30 h. The reaction mixture was cooled and poured into ice-water. (s, 3H, OCH3), 6.2 (s, 1H, CH), 7.0—8.1 (m, 12H, ArH), 8.4 (br s, 1H, NH).
The solid so obtained was filtered, washed with water, dried and recrystal- MS (m/z) : 405 (Mꢅ). Anal. Calcd for C22H17N4O2Cl: C, 65.27; H, 4.23; N,
lized from chloroform–benzene (25 : 75) mixture. Yieldꢁ74%, mp 196— 13.84. Found: C, 65.33; H, 4.21; N, 13.81.
200 °C; IR (KBr) cmꢀ1: 3350, 3320 (NHNH2), 1674 (CꢁO); 1H-NMR
2-(Nꢀ-(2-Nitro-benzylidene-hydrazino)-3-(4-methoxyphenyl)-quina-
(CDCl3) d (ppm): 3.79 (s, 3H, OCH3), 4.95 (s, 2H, NH2), 6.82—8.06 (m, zolin-4(3H)-one (A10) Compound A10 was prepared by adopting the
8H, ArH), 8.56 (s, 1H, NH); MS (m/z): 282 (Mꢅ); Anal. Calcd for same procedure as for A1 and obtained in 73% yield, mp 237—239 °C. IR
C15H14N4O2: C, 63.82; H, 4.99; N, 19.84. Found: C, 63.71; H, 4.95; N, (KBr) cmꢀ1: 3250 (NH), 1686 (CꢁO), 1620 (CꢁN). 1H-NMR (CDCl3) d
19.93.
ppm: 3.2 (s, 3H, OCH3), 6.1 (s, 1H, CH), 7.3—8.2 (m, 12H, ArH), 8.5 (br s,

80
Vol. 55, No. 1
1H, NH). MS (m/z) : 415 (Mꢅ). Anal. Calcd for C22H17N5O4: C, 63.61; H,
4.12; N, 16.86. Found: C, 63.67; H, 4.15; N, 16.82.
paw volumes were measured using the mercury displacement technique with
the help of a plethysmograph immediately before and 30 min, 1, 2 and 3 h
after carrageenan injection. The percent inhibition of paw oedema was cal-
culated using the following formula
2-(Nꢀ-(4-Nitro-benzylidene-hydrazino))-3-(4-methoxyphenyl)-quina-
zolin-4(3H)-one (A11) Compound A11 was prepared by adopting the
same procedure as for A1 and obtained in 77% yield, mp 231—233 °C. IR
(KBr) cmꢀ1: 3293 (NH), 1687 (CꢁO), 1616 (CꢁN). 1H-NMR (CDCl3) d
ppm: 3.4 (s, 3H, OCH3), 6.3 (s, 1H, CH), 7.0—8.2 (m, 12H, ArH), 8.7 (br s,
1H, NH). MS (m/z): 415 (Mꢅ). Anal. Calcd for C22H17N5O4: C, 63.61; H,
4.12; N, 16.86. Found: C, 63.65; H, 4.14; N, 16.83.
2-(Nꢀ-(4-Methoxy-benzylidene-hydrazino))-3-(4-methoxyphenyl)-
quinazolin-4(3H)-one (A12) Compound A12 was prepared by adopting
the same procedure as for A1 and obtained in 73% yield, mp 256—258 °C.
IR (KBr) cmꢀ1: 3276 (NH), 1683 (CꢁO), 1611 (CꢁN). 1H-NMR (CDCl3) d
ppm: 2.7 (s, 3H, OCH3), 3.3 (s, 3H, OCH3), 6.5 (s, 1H, CH), 7.0—8.2 (m,
12H, ArH), 8.5 (br s, 1H, NH). MS (m/z): 400 (Mꢅ). Anal. Calcd for
C23H20N4O3: C, 68.99; H, 5.03; N, 13.99. Found: C, 68.94; H, 5.07; N,
13.96.
2-(Nꢀ-(2-Methyl-benzylidene-hydrazino))-3-(4-methoxyphenyl)-quina-
zolin-4(3H)-one (A13) Compound A13 was prepared by adopting the
same procedure as for A1 and obtained in 76% yield, mp 230—232 °C. IR
(KBr) cmꢀ1: 3318 (NH), 1684 (CꢁO), 1615 (CꢁN). 1H-NMR (CDCl3) d
ppm: 2.3 (s, 3H, CH3), 3.1 (s, 3H, OCH3), 6.2 (s, 1H, CH), 7.0—8.1 (m,
12H, ArH), 8.4 (s, 1H, NH). MS (m/z): 384 (Mꢅ). Anal. Calcd for
C23H20N4O2: C, 71.86; H, 5.24; N, 14.57. Found: C, 71.82; H, 5.25; N,
14.60.
percent inhibition Iꢁ100[1ꢀ(aꢀx)/(bꢀy)]
Where x is the mean paw volume of rats before the administration of car-
rageenan and test compounds or reference compound (test group), a is the
mean paw volume of rats after the administration of carrageenan in the test
group (drug treated), b is the mean paw volume of rats after the administra-
tion of carrageenan in the control group, y is the mean paw volume of rats
before the administration of carrageenan in the control group.
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 daily for 3 d. The remain-
ing group of animals was administered with test compounds intraperi-
toneally in a dose of 20 mg/kg. On fourth day, pylorus was ligated as per the
method of Shay et al.18) Animals were fasted for 36 h before the pylorus lig-
ation 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 Bhatnagar19) and
recorded in Table 3.
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 in-
dividual groups were performed using Tukey’s test. A significance level of
pꢃ0.05 denoted significance in all cases. All values are expressed as
meanꢂS.D. (standard deviations). For statistical analysis we have used
GraphPad Prism 3.0 version. (GraphPad Prism 3.0 version, GraphPad Soft-
ware, Inc.11452 El Camino Real, #215, San Diego, CA 92130 U.S.A.).
2-(Nꢀ-(4-Methyl-benzylidene-hydrazino)-3-(4-methoxyphenyl)-quina-
zolin-4(3H)-one (A14) Compound A14 was prepared by adopting the
same procedure as for A1 and obtained in 76% yield, mp 258—259 °C. IR
(KBr) cmꢀ1: 3240 (NH), 1692 (CꢁO), 1616 (CꢁN). 1H-NMR (CDCl3) d
ppm: 2.1 (s, 3H, CH3), 3.3 (s, 3H, OCH3), 6.6 (s, 3H, CH3), 7.3—8.4 (m,
12H, ArH), 8.6 (br s, 1H, NH). MS (m/z): 384 (Mꢅ). Anal. Calcd for
C23H20N4O2: C, 71.86; H, 5.24; N, 14.57. Found: C, 71.82; H, 5.27; N,
14.61.
2-(Nꢀ-Phenyl-benzylidene-hydrazino)-3-(4-methoxyphenyl)-quina-
zolin-4(3H)-one (A15) Compound A15 was prepared by adopting the
same procedure as for A1 and obtained in 79% yield, mp 251—253 °C. IR
(KBr) cmꢀ1: 3270 (NH), 1692 (CꢁO), 1613 (CꢁN). 1H-NMR (CDCl3) d
ppm: 3.5 (s, 3H, OCH3), 7.1—8.4 (m, 18H, ArH), 8.7 (br s, 1H, NH). MS
(m/z): 446 (Mꢅ). Anal. Calcd for C28H22N4O2: C, 75.32; H, 4.97; N, 12.55.
Found: C, 75.38; H, 4.92; N, 12.56.
Pharmacology The synthesized compounds were evaluated for anal-
gesic, anti-inflammatory, ulcerogenicindex and antimicrobial activities. Stu-
dent t-test was performed to ascertain the significance of all the exhibited
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 ulcero-
genicity studies by intra peritoneally 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
25ꢂ2 °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 the
protocol adopted for the experimentation of animals.
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Analgesic Activity Test for analgesic activity was performed by tail-
flick technique14,15) using Wistar albino mice (25—35 g) of either sex se-
lected 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 com-
parison. The test compounds at two dose levels (10, 20 mg/kg) were admin-
istered orally. The reaction 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,




T2ꢀT1
16) Winter C. A., Risely E. A., Nu G. N., Proc. Soc. Exp. Biol., 111,
544—547 (1982).
17) Goyal R. K., Chakrabarthi A., Sanyal A. K., Planta Medica, 29, 85—
88 (1985).
18) Shay H., Komarov S. A., Fels S. E., Mmeraze D., Gruenstei M., Siplet
H., Gastroenterology, 5, 43—61 (1945).
19) Ganguly A. K., Bhatnagar O. P., Canadian J. Physiol. Pharmacol., 51,
748—750 (1973).
PAAꢁ
ꢆ100
10ꢀT




1
where T1 is the reaction time (s) before treatment, and T2 is the reaction time
(s) after treatment.
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 levels (10 mg, 20 mg/kg). The