Synthesis and analgesic, anti-inflammatory activities of 3-(3-methoxyphenyl)-2-substituted amino-quinazolin-4 (3H)-ones

Article abstract of DOI:10.1007/s00044-010-9417-z

A variety of novel 3-(3-methoxyphenyl)-2- substituted amino-quinazolin- 4(3H)-ones were synthesized by reacting the amino group of 2-hydrazino-3-(3- methoxyphenyl)- quinazolin-4(3H)-one with a variety of aldehydes and ketones. The starting material 2-hydrazino-3-(3- methoxyphenyl)-quinazolin-4(3H)-one was synthesized from 3-methoxy aniline. The title compounds were investigated for analgesic, anti-inflammatory, and ulcerogenic behavior. Among these the compound 2-(1-methyl butylidene- hydrazino)-3-(3-methoxyphenyl)-3H-quinazolin-4-one (AS3) emerged as the most active compound for the analgesic activity, while the compound 2-(1-ethyl propylidene- hydrazino)-3-(3-methyoxyphenyl)-3H-quinazolin- 4- one (AS2) showed most potent anti-inflammatory activity of the series and these compounds are moderately more potent when compared to the reference standard diclofenac sodium. Interestingly the test compounds showed only mild ulcerogenic potential when compared to acetylsalicylic acid. Springer Science+Business Media, LLC 2010.

Full text of DOI:10.1007/s00044-010-9417-z

MEDICINAL
CHEMISTRY
RESEARCH
Med Chem Res (2011) 20:946–954
DOI 10.1007/s00044-010-9417-z
ORIGINAL RESEARCH
Synthesis and analgesic, anti-inflammatory activities
of 3-(3-methoxyphenyl)-2-substituted amino-quinazolin-4
(3H)-ones
•
V. Alagarsamy M. Gopinath P. Parthiban
•
•
•
B. Subba Rao K. Murali V. Raja Solomon
•
Received: 16 March 2010 / Accepted: 18 August 2010 / Published online: 16 September 2010
Ó Springer Science+Business Media, LLC 2010
Abstract A variety of novel 3-(3-methoxyphenyl)-2-
substituted amino-quinazolin-4(3H)-ones were synthesized
by reacting the amino group of 2-hydrazino-3-(3-methoxy-
phenyl)-quinazolin-4(3H)-one with a variety of aldehydes
and ketones. The starting material 2-hydrazino-3-(3-
methoxyphenyl)-quinazolin-4(3H)-one was synthesized
from 3-methoxy aniline. The title compounds were inves-
tigated for analgesic, anti-inflammatory, and ulcerogenic
behavior. Among these the compound 2-(1-methyl butyli-
dene-hydrazino)-3-(3-methoxyphenyl)-3H-quinazolin-4-one
(AS3) emerged as the most active compound for the
analgesic activity, while the compound 2-(1-ethyl propyl-
idene-hydrazino)-3-(3-methyoxyphenyl)-3H-quinazolin-4-
one (AS2) showed most potent anti-inflammatory activity
of the series and these compounds are moderately more
potent when compared to the reference standard diclofenac
sodium. Interestingly the test compounds showed only mild
ulcerogenic potential when compared to acetylsalicylic acid.
Keywords Quinazoline ꢀ Analgesic ꢀ Anti-inflammatory ꢀ
Ulcer index
Introduction
Nonsteroidal anti-inflammatory drugs (NSAIDs) are com-
monly prescribed for the treatment of acute and chronic
inflammation, pain, and fever. 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
(Van Ryn, 1971; Van Ryn and Botting, 1995; Van Ryn
et al., 2000; Beuck, 1999). As part of our ongoing
medicinal chemistry research program we found that
quinazolines and condensed quinazolines exhibit potent
central nervous system (CNS) activities including analge-
sic, anti-inflammatory (Alagarsamy et al., 2003a), and
anticonvulsant (Alagarsamy et al., 2006). Quinazolin-
4(3H)-ones with 2,3-disubstitution are reported to possess
significant analgesic, anti-inflammatory (Abdel-Rahman
et al., 2003; Chambhare et al., 2003), and anticonvulsant
effects (Santagati et al., 1995). Previously we have docu-
mented some lead compound 2-phenyl-3-substituted quin-
azolines (Alagarsamy et al., 2002), 2-methyl-3-substituted
quinazolines (Alagarsamy et al., 2003b), 2-methylthio-3-
substituted quinazolines (Alagarsamy et al., 2004), and 2,
3-disubstituted quinazolines (Alagarsamy et al., 2003c)
that exhibited good analgesic and anti-inflammatory
activities. The present work is an extension of our ongoing
efforts toward the development and identification of new
molecules for analgesic and anti-inflammatory activities
with minimal gastrointestinal ulceration side effects. The
present work is an extension of our ongoing efforts toward
V. Alagarsamy (&) ꢀ P. Parthiban ꢀ B. Subba Rao
Medicinal Chemistry Research Laboratory, MNR College
of Pharmacy, MNR Nagar, Sangareddy, Gr. Hyderabad 502 294,
India
e-mail: drvalagarsamy@gmail.com
M. Gopinath
Department of Pharmaceutical Chemistry, Ratnam Institute
of Pharmacy, Pidathapolur, Nellore 524 346, India
K. Murali
Department of Pharmaceutical Chemistry, C.L. Baid Metha
College of Pharmacy, Thorappakkam, Chennai 600 097, India
V. Raja Solomon
Medicinal and Process Chemistry Division, Central Drug
Research Institute, Lucknow 226 001, India
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Med Chem Res (2011) 20:946–954
947
the development and identification of new molecules for
analgesic and anti-inflammatory activities with minimal
gastrointestinal ulceration side effects. In the present study,
we have synthesized a series of 3-(3-methoxyphenyl)-2-
substituted amino-quinazolin-4(3H)-ones. The synthesized
compounds were tested for their analgesic, anti-inflam-
matory, and ulcerogenic behavior.
NH2 signals at 3368 and 3210 cm-1 in the IR spectra. It
also showed a peak for carbonyl (C=O) at 1678 cm-1. The
1H-NMR spectra of the compound 6 showed singlets at d
3.50, 5.31, and 9.35 ppm due to CH3, NH2, and NH,
respectively, a multiplet at d 7.33–7.84 ppm was observed
for aromatic (8H) protons. Elemental analyses data and
mass spectral data is also in agreement with the assigned
structure of the compound.
The title compounds 3-(3-methoxyphenyl)-2-substituted
amino-3H-quinazolin-4-ones AS1–15 were obtained by
the condensation of amino group of 2-hydrazino-3-
(3-methoxyphenyl)-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
Results and discussion
Synthetic route depicted in Scheme 1 outline the chemis-
try part of the present work. The key intermediate
3-(3-methoxyphenyl)-2-thioxo-2,3-dihydro-1H-quinazolin-
4-one (4) was obtained by reacting 3-methoxy aniline (1)
with carbon disulphide and sodium hydroxide in dimethyl
sulphoxide to give sodium dithiocarbamate, which was
methylated with dimethyl sulphate to afford the dithioc-
arbamic acid methyl ester (2). Compound 2 on reflux
with methyl anthranilate (3) in ethanol yielded the desired
3-(3-methoxyphenyl)-2-thioxo-2,3-dihydro-1H-quinazolin-
4-one (4) via the thiourea intermediate in good yield
(85%). It was confirmed by IR spectra of 4 show intense
peaks at 3312 cm-1 for cyclic thio urea (NH), 1690 cm-1
for carbonyl (C=O), and 1210 cm-1 for thioxo (C=S)
stretching. 1H-NMR spectra of compound 4 showed singlet
at d 3.12 ppm due to OCH3 group, a multiplet at d
7.33–7.95 ppm for aromatic (8H) protons and a singlet at d
10.52 ppm indicating the presence of NH. Data from the
elemental analyses have been found to be in conformity
with the assigned structure. Furthermore the molecular ion
recorded in the mass spectra is also in agreement with the
molecular weight of the compound.
1
starting material in IR and H-NMR spectrum of all the
compounds AS1–15. 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 mass spectra of the
title compounds showed molecular ion peaks corresponding
to their molecular formulae. In mass spectrum of compounds
AS1–15 a common peak at m/z 144 corresponding to qui-
nazolin-4-one moiety appeared. The M??2 peaks were
observed in the spectra of compounds AS8 and AS9, con-
firming the presenceofa chlorineatominthe compounds. The
relative intensities of these M??2 peaks in comparison with
M? peaks were in the ratio of 1:3. Elemental (C, H, and N)
analyses satisfactorily confirmed elemental composition and
purity of the synthesized compounds.
Evaluation of analgesic activity was performed by the
tail-flick technique using Wistar albino mice (Kulkarni,
1980; Amour and Smith, 1941). The results of analgesic
testing indicate that the test compounds exhibited moderate
analgesic activity at 30 min of reaction time and an increase
in activity at 1 h which reached a peak level at 2 h. Declining
in activity was observed at 3 h (Table 1). Compound AS1
with 1-methylpropylidene substituent showed good activity;
with the increased lipophilicity (1-ethylpropylidene group,
compound AS2) showed an increase in activity. Replace-
ment of 1-ethylpropylidene group with its isomer 1-meth-
ylbutylidene group (compound AS3) retains the activity.
Replacement of C-2 alkyl chain with a cycloalkyl group and
an aralkyl group (compounds AS4 and AS5, respectively)
leads to a moderate decrease in activity. Placement of aryl
group at the N-3 position (compounds AS6, AS7, and AS13-
15) also results in decreasing the activity. Placement of
electron withdrawing group at N-3 aryl ring (compounds
AS8–12) leads to further decrease of activity. 2-(1-methyl
butylidene-hydrazino)-3-(3-methoxyphenyl)-3H-quinazolin
-4-one (AS3) emerged as the most active analgesic agent and
it is moderately more potent when compared to the reference
standard diclofenac.
The 3-(3-methoxyphenyl)-2-methysulfanyl-3H-quinazo-
lin-4-one 5 was obtained by dissolving 4 in 2% alcoholic
sodium hydroxide solution and methylating with dimethyl
sulphate with stirring at room temperature. 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 1690 cm-1. The 1H-NMR spectra of compound
5 showed singlets at d 2.84 and 3.35 ppm due to SCH3 and
OCH3, respectively, a multiplet at d 7.25–7.77 ppm was
observed for aromatic (8H) protons. Data from the elemental
analyses and molecular ion recorded in the mass spectra
further confirmed the assigned structure.
Nucleophilic displacement of the methylthio group of 5
with hydrazine hydrate was carried out using ethanol as
solvent to afford 2-hydrazino-3-(3-methoxyphenyl)-3H-
quinazolin-4-one 6. The long duration of reaction (35 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 compound 6 was confirmed by the presence of NH and
Anti-inflammatory activity was evaluated by the carra-
genenan-induced paw edema test in rats (Winter et al.,
123

948
Med Chem Res (2011) 20:946–954
Scheme 1 Synthesis of 3-(3-
methoxyphenyl)-2-substituted
amino-3H-quinazolin-4-ones.
Reagents and conditions: (a)
DMSO, rt, 30 min; (b)
OCH3
SCH3
OCH3
OCH3
S-Na+
S
b
a
N
S
CS2 / NaOH
N
NH2
H
H
(CH3)2SO4, 5–10°C, 2 h; (c)
methyl anthranilate (3), K2CO3,
ethanol reflux for 23 h; (d) 2%
alcoholic NaOH, (CH3)2SO4, rt,
1 h; (e) NH2NH2, K2CO3,
ethanol reflux for 35 h; and (f)
(R2R1)CO; CH3COOH reflux,
38 h
1
2
3-Methoxy aniline
c
OCH3
OCH3
O
N
OCH3
O
OCH3
NH
O
d
N
N
S
SCH3
N
H
N
S
H
5
3a
4
e
OCH3
OCH3
O
N
O
f
N
N
R1
R2
NH
N
NHNH2
CH3
AS1-AS15
N
6
AS1
AS6
AS11
C
H
NO2
O
CH2CH3
N
H
CH2CH3
CH2CH3
C
H
AS2
AS3
AS7
AS8
AS9
AS12
AS13
C
H
OCH3
Cl
H3C
CH3
C
H
C
H
CH2CH2CH3
C
H
CH3
AS4
AS5
AS14
AS15
C
H
Cl
O2N
CH3
AS10
C
H
1962). The anti-inflammatory activity data (Table 2) indi-
cated that all the test compounds protected rats from car-
rageenan-induced inflammation moderately at 30 min of
reaction time with increased activity at 1 h that reached
a peak level at 2 h. Decline in activity was observed at
3 h. The compound 2-(1-ethyl propylidene-hydrazino)-3-
(3-methyoxyphenyl)-3H-quinazolin-4-one (AS2) showed
the most potent anti-inflammatory activity of the series and
it is moderately more potent when compared to the refer-
ence standard diclofenac sodium.
with aliphatic substituents (compounds AS1–4) showed
negligible ulcer index, whereas aryl substituent (compound
AS5) exhibited little increase in ulcer index. When com-
pared to the reference standards ASA (ulcer index 1.73)
and diclofenac (ulcer index 1.65) the test compounds
exhibited about 35–50% of the ulcer index of the reference
standards. Compounds 2-(1-methylpropylidene-hydrazino)-
3-(3-methoxyphenyl)-3H-quinazolin-4-one (AS1) and 2-
(1-ethylpropylidene-hydrazino)-3-(3-methyoxyphenyl)-3H-
quinazolin-4-one (AS2) exhibited least ulcer index (0.53
and 0.51, respectively) among the test compounds which is
about one-third of the ulcer index of reference standards
aspirin and diclofenac.
The most potent compounds (AS1–5) of the series were
evaluated for their ulcerogenic behavior. The ulcer index of
the test compounds (Table 3) reveal that the compounds
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Med Chem Res (2011) 20:946–954
949
Table 1 Analgesic activity of
test compounds (tail-flick
technique)
Compound code
Percent analgesic activitya
30 min
1 h
2 h
3 h
AS1
53 1.43*
56 1.45***
57 1.52**
46 1.53*
44 1.94*
39 1.42*
40 1.16*
32 1.89*
34 1.29*
35 1.70*
35 1.84*
30 1.77*
39 1.59*
44 1.13*
41 1.99*
58 1.15**
61 1.73***
64 1.23***
49 1.14*
46 1.26*
43 1.78*
47 1.29*
39 1.55*
40 1.45*
41 1.50*
40 1.36*
37 1.49*
45 1.83**
48 1.08*
46 1.63*
61 1.24***
66 1.13***
68 1.87***
53 1.77**
51 1.76**
46 1.54*
47 1.83*
42 1.75*
42 1.87*
45 1.28**
42 1.63*
41 1.25*
51 1.77**
50 1.23**
49 1.39*
37 1.46*
38 1.57*
41 1.78*
38 1.68*
36 1.32*
36 1.28*
35 1.35*
33 1.83*
34 1.97*
36 1.13*
36 1.78*
30 1.19*
34 1.15*
37 1.35*
36 1.53*
AS2
AS3
AS4
AS5
AS6
AS7
AS8
AS9
AS10
AS11
AS12
AS13
AS14
AS15
Control
Diclofenac
Significance levels * p \ 0.5,
** p \ 0.01, and *** p \ 0.001
as compared with the respective
control. Control refers to no
treatment (vehicle only)
a
Data expressed as
mean SD from six different
experiments done in duplicate
2
0.35
6
0.49
4
0.59
4
0.91
37 1.69*
43 1.42*
45 0.92*
33 0.96*
Table 2 Anti-inflammatory
activity of test compounds
(carrageenan-induced paw
edema test in rats)
Compound code
Percent protection
30 min
1 h
2 h
3 h
AS1
41 1.16**
45 1.24**
42 1.63**
37 1.57*
39 1.72*
35 1.32*
35 1.27*
29 1.28*
33 1.32*
35 1.84*
33 1.38*
29 1.82*
36 1.84*
32 1.36*
33 1.71*
5.1 0.29
32 0.63*
45 1.28**
48 1.95**
47 1.42***
40 1.24**
42 1.38**
37 1.82*
38 1.34*
33 1.88*
36 1.42*
35 1.37*
35 1.65*
35 1.98*
41 1.32*
35 1.81**
38 1.71*
6.1 0.27
46 1.49**
53 1.33***
49 1.30***
43 1.72**
45 1.25**
40 1.49**
47 1.65**
37 1.33*
37 1.59*
38 1.83*
37 1.78*
37 1.20*
42 1.29*
40 1.62**
41 1.74**
5.7 0.32
32 1.42*
34 1.75*
34 1.29*
31 1.84*
32 1.49*
31 1.13*
31 1.53*
27 1.98*
27 1.42*
27 1.25*
29 1.49*
27 1.95*
30 1.49*
28 1.28*
30 1.46*
3.2 0.93
33 0.93*
AS2
AS3
AS4
AS5
AS6
AS7
AS8
AS9
AS10
AS11
AS12
AS13
AS14
AS15
Control
Diclofenac
Significance levels * p \ 0.5,
** p \ 0.01, and *** p \ 0.001
as compared with the respective
control. Control refers to no
treatment (vehicle only)
a
Data expressed as
mean SD from six different
experiments done in duplicate
38 1.58*
39 1.97*
Conclusion
such a group enhanced the analgesic and anti-inflammatory
activities. The most active compound of the C-2 phenyl
series 1-diethyl-3-(2-phenyl quinazolin-3-yl-4(3H)-one)
thiourea (Fig. 1, I) showed 44% analgesic and 38% anti-
inflammatory activity at the dose of 10 mg/kg, at the
reaction time of 2 h (Alagarsamy et al., 2002), whereas the
C-2 methyl series lead molecule 1-pyrrolidinyl-3-(2-methyl
quinazolin-3-yl-4(3H)-one) thiourea (Fig. 1, II) exhibited
In our earlier studies, we observed that the presence of
alkyl groups exhibited more analgesic and anti-inflamma-
tory activities over aryl groups at the N-3 position (Ala-
garsamy et al., 2002, 2003a, 2004). Hence, in the C-2
position also we made a substitution in such a way to
increase lipophilicity of the molecule. The placement of
123

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Med Chem Res (2011) 20:946–954
developed as a novel class of analgesic and anti-inflam-
matory agents.
Table 3 Evaluation of ulcerogenicity index
Compound
code
Ulcer indexa
AS1
0.53 1.36*
0.51 1.01*
0.58 1.53*
0.61 1.72*
0.62 1.12*
0.15 0.32
Materials and methods
AS2
AS3
Chemistry
AS4
AS5
Melting points (mp) were taken in open capillaries on
Thomas Hoover melting point apparatus (Thomas Hoover,
USA) and are uncorrected. The IR spectra were recorded in
film or in potassium bromide disks on a Perkin-Elmer 398
Control
Diclofenac
ASA
1.65 0.59**
1.73 0.41**
1
spectrometer (Perkin-Elmer, USA). The H spectra were
Significance levels * p \ 0.05 and ** p \ 0.01 as compared with the
respective control
recorded on a DPX-300 MHz Bruker FT-NMR spectrom-
eter (Bruker, 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, Japan) using fast atom
bombardment (FAB positive). Elemental analysis was
performed on a Perkin-Elmer 2400 CHN analyzer (Perkin-
Elmer, USA) and values were within the acceptable limits
of the calculated values ( 0.4%). The progress of the
reaction was monitored on readymade silica gel plates
(Merck, USA) using chloroform/methanol (9:1) as a sol-
vent system. Iodine was used as a developing agent. All
chemicals and reagents used in the synthesis were obtained
from Aldrich (USA), Lancaster (USA), or Spectrochem
(India) and were used without further purification.
a
Data expressed as mean SD from six different experiments done
in duplicate
50% analgesic and 44% anti-inflammatory activity at the
dose of 10 mg/kg, at the reaction time of 2 h (Alagarsamy
et al., 2003a). Introduction of sulphur atom at C-2 position
in the above series, i.e., by placing methylthio group at C-2
position compound 1-diethyl-3-(2-methylthio quinazolin-
3-yl-4(3H)-one) thiourea (Fig. 1, III) exhibited 56% anal-
gesic activity and 40% anti-inflammatory activity at
10 mg/kg, respectively, at the reaction time of 2 h. Results
of analgesic and anti-inflammatory activities of the present
series showed that moderate enhancement of activity,
compound AS3 exhibited 68% analgesic activity at 10 mg/kg
dose level at the reaction time of 2 h. The compound AS2
showed 53% anti-inflammatory activity at the dose of
10 mg/kg, at the reaction of 2 h. Interestingly these com-
pounds showed one-third of ulcer index of the reference
NSAIDs aspirin and diclofenac. Hence, this series could be
3-(3-Methoxyphenyl)-2-thioxo-2,3-dihydro-1H-
quinazolin-4-one (4)
A solution of 3-methoxy aniline 1 (0.02 mol) in dimethyl
sulfoxide (10 ml) was stirred vigorously. To this reaction
mixture carbon disulphide (1.6 ml) was added and aqueous
sodium hydroxide 1.2 ml (2 mol) added drop wise during
30 min with stirring. Dimethyl sulphate (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 filtered,
washed with water, dried and recrystallized from ethanol.
Methyl anthranilate (0.01 mol) and the above prepared
N-(3-methoxyphenyl)-methyl dithiocarbamic acid (0.01 mol),
were dissolved in ethanol (20 ml). To this anhydrous
potassium carbonate (100 mg) was added and refluxed for
23 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 re-precipitated by
treating with dilute hydrochloric acid. The solid obtained
was filtered, washed with water, dried, and recrystallized
from ethanol. Yield = 85%, mp 255–256°C. IR: 3312
(NH), 1690 (C=O), 1210 (C=S) cm-1. 1H-NMR (CDCl3): d
3.12 (s, 3H, OCH3), 7.33–7.95 (m, 8H, ArH), 10.52 (br s,
O
O
N
R
R
N
N
N
C6H5
CH3
(I)
(II)
OCH3
O
O
R
N
N
N
NH
N
N
SCH3
R1
R2
C
AS1-AS15
(III)
Fig. 1 Lead molecules of quinazolin-4-ones
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Med Chem Res (2011) 20:946–954
951
1H, NH). MS (m/z) 284 (M?). Anal. Calcd. for C15H12
N2O2S: C, 63.36; H, 4.25; N, 9.85. Found: C, 63.38; H,
4.30; N, 9.88.
2-(1-Ethyl propylidene-hydrazino)-3-
(3-methyoxyphenyl)-3H-quinazolin-4-one (AS2)
Compound AS2 was prepared by adopting the same proce-
dure as for AS1 and obtained in 82% yield, mp 261–262°C;
IR (KBr) cm-1: 3265 (NH), 1700 (C=O), 1615 (C=N); 1H-
NMR (CDCl3): d 0.75–0.95 (m, 4H, (CH2CH3)2), 1.56–1.78
(m, 6H, (CH2CH3)2), 2.86 (s, 3H, OCH3), 7.45–8.15 (m, 8H,
ArH), 8.9 (br s, 1H, NH D2O exchangeable); MS (m/z): 350
[M?]. Anal. Calcd. for C20H22N4O2: C, 68.55; H, 6.32; N,
15.98. Found: C, 68.59; H, 6.30; N, 15.95.
3-(3-Methoxyphenyl)-2-methylsulfanyl-3H-quinazolin-
4-one (5)
The 3-(3-methoxyphenyl)-2-thioxo-2,3-dihydro-1H-quinaz-
olin-4-one 4 (0.01 mol) was dissolved in 40 ml of 2%
alcoholic sodium hydroxide solution. To this dimethyl
sulphate (0.01 mol) was added drop wise 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, and recrystallized from ethanol–
chloroform (75:25) mixture. Yield = 86%, mp 155–156°C.
2-(1-Methyl butylidene-hydrazino)-3-
(3-methoxyphenyl)-3H-quinazolin-4-one (AS3)
1
IR: 1690 (C=O) cm-1. H-NMR (CDCl3): d 2.84 (s, 3H,
Compound AS3 was prepared by adopting the same proce-
dure as for AS1 and obtained in 78% yield, mp 253–254°C;
IR (KBr) cm-1: 3267 (NH), 1695 (C=O), 1612 (C=N); 1H-
NMR (CDCl3): d 1.2–1.3 (t, 2H, CH2CH2CH3), 1.8–1.9
(sext, 2H, CH2CH2CH3), 2.20–2.35 (t, 3H, CH2CH2CH3),
2.67 (s, 3H, CH3), 3.3 (s, 3H, OCH3), 7.34–8.15 (m, 9H,
ArH), 8.89 (br s, 1H, NH D2O exchangeable); MS (m/z): 350
[M?]. Anal. Calcd. for C20H22N4O2: C, 68.55; H, 6.32; N,
15.98. Found: C, 68.53; H, 6.28; N, 15.99.
SCH3), 3.35 (s, 3H, OCH3), 7.25–7.77 (m, 8H ArH); MS
(m/z) 298 (M?). Anal. Calcd. for C16H14N2O2S: C, 64.41;
H, 4.72; N, 9.38. Found: C, 64.45; H, 4.74; N, 9.33.
2-Hydrazino-3-(3-methoxphenyl)-3H-quinazolin-4-one
(6)
The 3-(3-methoxyphenyl)-2-methylsulfanyl-3H-quinazolin-
4-one 5 (0.01 mol) was dissolved in ethanol (25 ml). To
this hydrazine hydrate (99%) (0.1 mol) and anhydrous
potassium carbonate (100 mg) was added and refluxed for
35 h. The reaction mixture was cooled and poured into ice
water. The solid obtained was filtered, washed with water,
dried, and recrystallized from chloroform–benzene (25:75)
mixture. Yield = 79%, mp 211–213°C. IR: 3368, 3210
2-(N0-Cyclohexylidene-hydrazino)-3-
(3-methoxyphenyl)-3H-quinazolin-4-one (AS4)
Compound AS4 was prepared by adopting the same pro-
cedure as for AS1 and obtained in 73% yield, mp
237–239°C; IR (KBr) cm-1: 3310 (NH), 1685 (C=O), 1610
1
(C=N); H-NMR (CDCl3): d 0.90–1.81 (m, 10H, cyclo-
1
(NHNH2), 1678 (C=O) cm-1. H-NMR (CDCl3): d 3.50
hexyl), 2.92–3.02 (s, 3H, OCH3), 7.24–7.85 (m, 8H, ArH),
8.33 (br s, 1H, NH D2O exchangeable); MS (m/z): 362
[M?]. Anal. Calcd. for C21H22N4O2: C, 69.59; H, 6.11; N,
15.45. Found: C, 69.63; H, 6.15; N, 15.44.
(s, 3H, OCH3), 5.31 (s, 2H, NH2), 7.33–7.84 (m, 8H, ArH),
9.35 (s, 1H, NH). MS (m/z) 282 (M?). Anal. Calcd. for
C15H14N4O2: C, 63.82; H, 4.99; N, 19.84. Found: C, 63.81;
H, 4.96; N, 19.87.
2-(N0-1-Phenylethylidene-hydrazino)-3-
(3-methoxyphenyl)-3H-quinazolin-4-one (AS5)
2-(1-Methylpropylidene-hydrazino)-3-
(3-methoxyphenyl)-3H-quinazolin-4-one (AS1)
CompoundAS5 waspreparedbyadoptingthesameprocedure
as for AS1 and obtained in 73% yield, mp 263–264°C; IR
(KBr) cm-1: 3310 (NH), 1685 (C=O), 1610 (C=N); 1H-NMR
(CDCl3): d 1.63 (s, 3H, CH3), 3.01 (s, 3H, OCH3), 7.24–8.25
(m, 13H, ArH), 8.87 (br s, 1H, NH D2O exchangeable); MS
(m/z): 384 [M?]. Anal. Calcd. for C23H20N4O2: C, 71.85; H,
5.24; N, 14.57. Found: C, 71.88; H, 5.22; N, 14.59.
A mixture of 2-hydrazino-3-(3-methoxyphenyl)-3H-qui-
nazolin-4-one (6) (0.004 mol) and ethyl methyl ketone
(0.004 mol) in glacial acetic acid was refluxed for 38 h.
The reaction mixture was poured into ice water. The solid
obtained was recrystallized from ethanol. Yield = 72%,
mp 243–245°C; IR (KBr) cm-1: 3210 (NH), 1685 (C=O),
1617 (C=N); 1H-NMR (CDCl3): d 1.00–1.15 (q, 2H,
CH2CH3), 1.32–1.45 (t, 3H, CH2CH3), 2.36 (s, 3H, CH3),
3.01 (s, 3H, OCH3), 7.44–8.06 (m, 8H, ArH), 8.55 (br s,
1H, NH D2O exchangeable); MS (m/z): 336 [M?]. Anal.
Calcd. for C19H20N4O2: C, 67.83; H, 5.99; N, 16.65.
Found: C, 67.88; H, 5.97; N, 16.68.
2-(N0-2-Oxo-indolin-2-one-3-yl-idene-hydrazino)-3-
(3-methoxyphenyl)-3H-quinazolin-4-one (AS6)
Compound AS6 was prepared by adopting the same pro-
cedure as for AS1 and obtained in 83% yield, mp
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Med Chem Res (2011) 20:946–954
294–295°C; IR (KBr) cm-1: 3285 (NH), 1670 (C=O),
1613 (C=N); H-NMR (CDCl3): d 2.94 (s, 3H, OCH3),
2-(N0-(4-Nitro-benzylidene-hydrazino))-3-
(3-methoxyphenyl)-3H-quinazolin-4-one (AS11)
1
7.25–8.10 (m, 12H, ArH), 8.91 (br s, 1H, NH D2O
exchangeable), 9.34 (br s, 1H, NH D2O exchangeable); MS
(m/z): 411 [M?]. Anal. Calcd. for C23H17N4O3: C, 67.14;
H, 4.16; N, 13.61. Found: C, 67.15; H, 4.18; N, 13.60.
Compound AS11 was prepared by adopting the same
procedure as for AS1 and obtained in 70% yield, mp
199–201°C; IR (KBr) cm-1: 3278 (NH), 1680 (C=O), 1610
1
(C=N); H-NMR (CDCl3): d 2.93 (s, 3H, OCH3), 6.35 (s,
2-(N0-Benzylidene-hydrazino)-3-(3-methoxyphenyl)-
3H-quinazolin-4-one (AS7)
1H, CH), 7.31–8.23 (m, 12H, ArH), 8.84 (br s, 1H, NH
D2O exchangeable); MS (m/z): 415 [M?]. Anal. Calcd. for
C22H17N5O4 C, 63.61; H, 4.12; N, 16.86. Found: C, 63.58;
H, 4.14; N, 16.91.
CompoundAS7 waspreparedbyadoptingthesameprocedure
as for AS1 and obtained in 77% yield, mp 267–268°C; IR
(KBr) cm-1: 3290 (NH), 1690 (C=O), 1614 (C=N); 1H-NMR
(CDCl3): d 3.32 (s, 3H, CH3), 5.81 (s, 1H, CH), 7.22–8.25 (m,
13H, ArH), 8.86 (br s, 1H, NH D2O exchangeable); MS (m/z):
370 [M?]. Anal. Calcd. for C22H18N4O2: C, 71.33; H, 4.89; N,
15.12. Found: C, 71.37; H, 4.90; N, 15.10.
2-(N0-(4-Methoxy-benzylidene-hydrazino))-3-
(3-methoxyphenyl)-3H-quinazolin-4-one (AS12)
Compound AS12 was prepared by adopting the same
procedure as for AS1 and obtained in 77% yield, mp
290–291°C; IR (KBr) cm-1: 3260 (NH), 1687 (C=O), 1615
(C=N); 1H-NMR (CDCl3): d 3.24 (s, 3H, CH3), 3.43 (s, 3H,
OCH3), 6.32 (s, 1H, CH), 7.01–8.15 (m, 12H, ArH), 8.56
(br s, 1H, NH D2O exchangeable); MS (m/z): 400 [M?)].
Anal. Calcd. for C23H20N4O3 C, 68.99; H, 5.03; N, 13.99.
Found: C, 68.96; H, 5.04; N, 13.98.
2-(N0-(2-Chloro-benzylidene-hydrazino))-3-
(3-methoxyphenyl)-3H-quinazolin-4-one (AS8)
Compound AS8 was prepared by adopting the same pro-
cedure as for AS1 and obtained in 73% yield, mp
216–218°C; IR (KBr) cm-1: 3360 (NH), 1700 (C=O), 1610
(C=N); 1H-NMR (CDCl3):d 3.12 (s, 3H, OCH3), 6.01
(s, 1H, CH), 7.21–8.13 (m, 12H, ArH), 8.65 (br s, 1H, NH
D2O exchangeable); MS (m/z): 405 [M?], 407 [M? ?2];
Anal. Calcd. for C22H17N4O2Cl: C, 65.27; H, 4.23; N,
13.84. Found: C, 65.21; H, 4.26; N, 13.87.
2-(N0-(2-Methyl-benzylidene-hydrazino))-3-
(3-methoxyphenyl)-3H-quinazolin-4-one (AS13)
Compound AS13 was prepared by adopting the same
procedure as for AS1 and obtained in 80% yield, mp
248–249°C; IR (KBr) cm-1: 3330 (NH), 1683 (C=O), 1612
(C=N); 1H-NMR (CDCl3): d 1.32 (s, 3H, CH3), 2.83 (s, 3H,
OCH3), 6.04 (s, 1H, CH), 7.02–8.03 (m, 12H, ArH), 8.75
(br s, 1H, NH D2O exchangeable); MS (m/z): 384 [M?].
Anal. Calcd. for C23H20N4O2: C, 71.86; H, 5.24; N, 14.57.
Found: C, 71.85; H, 5.22; N, 15.59.
2-(N0-(4-Chloro-benzylidene-hydrazino)-3-
(3-methoxyphenyl)-3H-quinazolin-4-one (AS9)
Compound AS9 was prepared by adopting the same pro-
cedure as for AS1 and obtained in 74% yield, mp
273–274°C; IR (KBr) cm-1: 3225 (NH), 1670 (C=O), 1615
1
2-(N0-(4-Methyl-benzylidene-hydrazino)-3-
(3-methoxyphenyl)-3H-quinazolin-4-one (AS14)
(C=N); H NMR (CDCl3): d 3.31 (s, 3H, OCH3), 5.82 (s,
1H, CH), 7.34–8.26 (m, 12H, ArH), 8.97 (br s, 1H, NH
D2O exchangeable); MS (m/z): 405 [M?], 407 [M? ?2].
Anal. Calcd. for C22H17N4O2Cl: C, 65.27; H, 4.23; N,
13.84. Found: C, 65.24; H, 4.26; N, 13.85.
Compound AS14 was prepared by adopting the same
procedure as for AS1 and obtained in 74% yield, mp
261–262°C; IR (KBr) cm-1: 3310 (NH), 1670 (C=O), 1611
(C=N); 1H-NMR (CDCl3): d 1.03 (s, 3H, CH3), 2.8 (s, 3H,
OCH3), 6.04 (s, 1H, CH), 7.32–8.25 (m, 12H, ArH), 9.02
(br s, 1H, NH D2O exchangeable); MS (m/z): 384 [M?].
Anal. Calcd. for C23H20N4O2: C, 71.86; H, 5.24; N, 14.57.
Found: C, 71.79; H, 5.25; N, 14.60.
2-(N0-(2-Nitro-benzylidene-hydrazino)-3-
(3-methoxyphenyl)-3H-quinazolin-4-one (AS10)
Compound AS10 was prepared by adopting the same
procedure as for AS1 and obtained in 79% yield, mp
220–221°C; IR (KBr) cm-1: 3310 (NH), 1687 (C=O), 1611
(C=N); 1H-NMR (CDCl3): d 3.53 (s, 3H, CH3), 6.04 (s, 1H,
CH), 7.15–8.06 (m, 12H, ArH), 8.67 (br s, 1H, NH D2O
exchangeable); MS (m/z): 415 [M?]. Anal. Calcd. for
C22H17N5O4 C, 63.61; H, 4.12; N, 16.86. Found: C, 63.62;
H, 4.11; N, 16.90.
2-(N0-Phenyl-benzylidene-hydrazino)-3-
(3-methoxyphenyl)-3H-quinazolin-4-one (AS15)
Compound AS15 was prepared by adopting the same
procedure as for AS1 and obtained in 71% yield, mp
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Med Chem Res (2011) 20:946–954
953
230–231°C; IR (KBr) cm-1: 3330 (NH), 1679 (C=O), 1610
(C=N); 1H-NMR (CDCl3): d 3.32 (s, 3H, OCH3),
7.11–8.44 (m, 18H, ArH), 8.75 (br s, 1H, NH D2O
exchangeable); MS (m/z): 446 [M?]. Anal. Calcd. for
C28H22N4O2: C, 75.32; H, 4.97; N, 12.55. Found: C, 75.36;
H, 4.94; N, 12.56.
injection. The percent inhibition of paw edema was cal-
culated using the following formula:
Percent inhibition I ¼ 100½1 ꢁ ða ꢁ xÞ=ðb ꢁ yÞꢃ;
where x is the mean paw volume of rats before the
administration of carrageenan and test compounds or ref-
erence 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 administration of carrageenan in the control group, and
y is the mean paw volume of rats before the administration
of carrageenan in the control group.
Pharmacology
The synthesized compounds were evaluated for analgesic,
anti-inflammatory, and ulcerogenic index. The test com-
pounds and the standard drugs were administered in the
form of a suspension (using 1% carboxy methyl cellulose
as a vehicle) by oral route of administration for analgesic
and anti-inflammatory but for ulcerogenicity studies intra-
peritoneally as suspension in 10% v/v Tween 80. Each
group consisted of six animals. The animals were main-
tained in colony cages at 25 2°C, relative humidity
45–55%, under a 12 h light dark cycle; they were fed
standard animal feed. All the animals were acclimatized for
a week before use. The Institutional Animal Ethics com-
mittee approved the protocol adopted for the experimen-
tation of animals.
Evaluation of ulcerogenicity index
Ulceration in rats was induced as described by Goyal et al.
(1985). 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
10% v/v Tween 80 suspension intraperitoneally. One group
was administered with Aspirin (German Remedies) intra-
peritoneally at a dose of 20 mg/kg once daily for 3 days.
The remaining group of animals was administered with test
compounds intraperitoneally at a dose of 20 mg/kg. On the
fourth day, pylorus was ligated as per the method (Shay
et al., 1945). Animals were fasted for 36 h before the
pylorus ligation procedure. Four hours after the ligation,
animals were killed. The stomach was removed and opened
along with the greater curvature. Ulcer index was deter-
mined by the method of Ganguly and Bhatnagar (1973) and
is recorded in Table 3.
Analgesic activity
Test for analgesic activity was performed by tail-flick
technique (Kulkarni, 1980; Amour and Smith, 1941) 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 the
reference drug for comparison. The test compounds at two
dose levels (10 and 20 mg/kg) were administered orally.
The reaction time was recorded at 30 min, 1, 2 and 3 h
after the treatment, and the cut-off time was 10 s. The
percentage analgesic activity (PAA) was calculated by the
following formula:
Statistical analysis
Statistical analysis of the biological activity of the synthe-
sized compounds on animals was evaluated using a one-way
analysis of variance (ANOVA). In all cases, post-hoc com-
parisons of the means of individual groups were performed
using Tukey’s test. A significance level of P \ 0.05 denoted
significance in all cases. All values are expressed as
mean SD (standard deviations). For statistical analysis,
we have used GraphPad Prism version 3.0. (GraphPad Prism
version 3.0, GraphPad Software, Inc. San Diego, CA).
ꢀ
ꢁ
T2 ꢁ T1
10 ꢁ T1
where T1 is the reaction time (s) before treatment and T2 is
PAA ¼
ꢂ 100;
the reaction time (s) after treatment.
Anti-inflammatory activity
Acknowledgments The authors thank the head, Department of
Chemistry, Indian Institute of Technology, Chennai for the mass
spectral data and the head, sophisticated analytical instrument facilities,
Central Drug Research Institute, Lucknow for NMR spectral data.
Anti-inflammatory activity was evaluated by carrageenan-
induced paw edema test in rats (Winter et al., 1962).
Diclofenac sodium 10 and 20 mg/kg was administered as a
standard drug for comparison. The test compounds were
administered at two dose levels (10 and 20 mg/kg). The
paw volumes were measured using the mercury displace-
ment technique with the help of a plethysmograph imme-
diately before and 30 min, 1, 2 and 3 h after carrageenan
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