Synthesis, analgesic, anti-inflammatory and antibacterial activities of some novel 2-phenyl-3-substituted quinazolin-4(3H) ones.

Article abstract of DOI:10.1248/bpb.25.1432

A series of novel 2-phenyl-3-substituted quinazolin-4(3H)-ones have been synthesized by treating methyl-N-(2-phenyl quinazolin-3-yl-4(3H)-one) dithiocarbamate with different amines, the starting material dithiocarbamate was synthesized from anthranilic ac

Full text of DOI:10.1248/bpb.25.1432

1432
Biol. Pharm. Bull. 25(11) 1432—1435 (2002)
Vol. 25, No. 11
Synthesis, Analgesic, Anti-inflammatory and Antibacterial Activities of
Some Novel 2-Phenyl-3-substituted Quinazolin-4(3H) Ones
Veerachamy ALAGARSAMY,* Viswas Raja SALOMON, Gnanavel VANIKAVITHA, Veeran PALUCHAMY,
Muniyandi Ravi CHANDRAN, Augustin Arnald SUJIN, Arunachalam THANGATHIRUPPATHY,
Sivaperuman AMUTHALAKSHMI, and Rajappan REVATHI
Medicinal Chemistry Laboratory, S.B. College of Pharmacy; Sivakasi-626 130, India.
Received May 30, 2002; accepted August 7, 2002
A series of novel 2-phenyl-3-substituted quinazolin-4(3H)-ones have been synthesized by treating methyl-N-
(2-phenyl quinazolin-3-yl-4(3H)-one) dithiocarbamate with different amines, the starting material dithiocarba-
mate was synthesized from anthranilic acid. The title compounds were investigated for analgesic, anti-inflamma-
tory and antibacterial activities. All the test compounds exhibited significant activity, the compounds A1, A2 and
A3 shown more potent analgesic activity, and the compound A3 shown more potent anti-inflammatory activity
than the reference standard diclofenac sodium.
Key words quinazoline; analgesic; anti-inflammatory; thioureas; pyrimidine
Bacterial infections often produce inflammation and pain. (CDCl3) d: 6.8—7.5 (m, 9H, ArH); MS (m/z) 223 (Mϩ).
In normal practice, two groups of agents (Chemotherapeutic, Anal. Calcd for C14H9NO2: C, 75.33; H, 4.03; N, 6.27.
analgesic and anti-inflammatory) are prescribed simultane- Found: C, 75.37; H, 3.99; N, 6.31.
ously. The compounds possessing all three activities are not
Synthesis of 3-Amino-2-phenyl quinazolin-4(3H)-one A
common. Quinazolines and condensed quinazolines exhibit mixture of 2-phenyl-3-benzoxazin-4-one (0.05 mol) and hy-
potent antimicrobial1) and central nervous system (CNS) ac- drazine hydrate (0.05 mol) in ethanol was refluxed for 3 h and
tivities like analgesic,2) anti-inflammatory3) and anticonvul- cooled. The separated solid was crystallized from ethanol,
sant4) activities. In view of these facts and as a continuation yieldϭ85%, mp 196 °C; IR (KBr) cmϪ1: 3300 (NH2), 1680
of our previous efforts carried out in our laboratory,5,6) 1- (cyclic CϭO), 1620 (CϭN) and 1600 (CϭC); 1H-NMR
(2-phenyl quinazolin-3-yl-4(3H)-one)-3-substituted thioureas (CDCl3) d: 4.5 (s, 2H, NH2), 6.7—7.4 (m, 9H, ArH); MS
were synthesized. The title compounds were prepared by nu- (m/z) 237 (Mϩ). Anal. Calcd for C14H11N3O: C, 70.88; H,
cleophilic substitution of methyl-N-(2-phenyl quinazolin-3- 4.64; N, 17.72. Found: C, 70.92; H, 4.67; N, 17.68.
yl-4(3H)-one dithiocarbamate with variety of amines. The
Synthesis of Methyl-N-(2-phenyl quinazolin-3-yl-4(3H)-
starting material dithiocarbamate was synthesized by react- one Dithiocarbamate To a vigorously stirred solution of
ing the amino group of 3-amino-2-phenyl quinazolin-4(3H)- 3-amino-2-phenyl quinazolin-4(3H)-one 4.74 g (0.02 mol) in
one with carbondisulphide, sodium hydroxide and dimethyl dimethyl sulphoxide (10 ml) at room temperature car-
sulphate (Chart 1). The chemical structures of the synthe- bondisulphide (1.6 ml, 0.026 mol) and sodium hydroxide
1
sized compounds were confirmed by H-NMR, IR and mass (1.2 ml, 20 mol) were added dropwise during 30 min, it was
spectral data, the purity was ascertained by elemental analy- allowed to stir for 30 min more. Dimethyl sulphate 2.5 g
sis. The synthesized compounds were tested for their anal- (0.02 mol) was added at 5—10 °C, stirring was continued for
gesic activity by tail-flick method, anti-inflammatory activity 3 h and the reaction mixture was poured into ice water, the
by carrageenan induced rat paw oedema method and antibac-
terial activity by agar dilution method.
CHEMISTRY
Melting points were determined in open capillary tubes on
a Thomas Hoover apparatus and are uncorrected. IR spectra
were recorded in KBr on a Perkin Elmer-841 grating spec-
trometer (cmϪ1), mass spectra on a varian Atlas CH-7 mass
spectrometer at 70 eV and NMR spectra on a varian A-60 or
EM-360 spectrometer, using tetramethylsilane (TMS) as in-
ternal standard. Elemental analysis were performed on Carlo
erba 1108.
Synthesis of 2-Phenyl-3,l-benzoxazin-4-one To a solu-
tion of anthranilic acid (0.1 mol) dissolved in pyridine
(60 ml), benzoyl chloride (0.2 mol) was added. The mixture
was stirred for 30 min followed by treatment with 5%
NaHCO3 (15 ml). The solid obtained was crystallized from
ethanol, yieldϭ80%, mp 120 °C; IR (KBr) cmϪ1: 3350 (NH),
Chart 1
1780 (CϭO) 1680 (cyclic CϭO) and 1620 (CϭN); NMR
* To whom correspondence should be addressed. e-mail: samy_veera@yahoo.com
© 2002 Pharmaceutical Society of Japan

November 2002
1433
solid, so obtained was filtered, washed with water, dried and
recrystallized from ethanol–chloroform mixture, yieldϭ78%,
mp 125 °C; IR (KBr) cmϪ1: 3310 (NH), 1680 (cyclic CϭO),
1620 (CϭN), 1600 (CϭC), 1150 (CϭS) and 650 cmϪ1
(C–S); 1H-NMR (CDCl3) d: 3.5—3.6 (s, 3H, CH3), 6.7—7.4
(m, 9H, ArH), 8.8—8.9 (s, 1H, NH); MS (m/z) 327 (Mϩ).
Anal. Calcd for C16H13N3OS2: C, 58.71; H, 3.97; N, 12.84.
Found: C, 58.68; H, 4.01; N, 12.87.
percent inhibition Iϭ100[1Ϫ(aϪx)/(bϪy)]
Where xϭthe mean paw volume of rats before the adminis-
tration of carrageenan and test compounds or standard com-
pound, a stands for mean paw volume of rats after the admin-
istration of carrageenan in the control group, b is the mean
paw volume of rats before the administration of carrageenan
in the control group, y is mean paw volume of rats after the
administration of carrageenan in the control group.
Synthesis of 1-(2-Phenyl quinazolin-3-yl-4(3H)-one)-3-
dimethyl Thiourea A mixture of methyl-N-(2-phenyl-3-yl-
4(3H)-one dithiocarbamate 3.27 g (0.01 mol) and dimethyl
amine 0.9 g (0.02 mol) in dimethyl formamide (20 ml) was
refluxed for 22 h cooled and poured into ice water, the solid
obtained was filtered, dried and recrystallized from chloro-
form, yieldϭ74%, mp 178 °C; IR (KBr) cmϪ1: 3310 (NH),
2850 (CH), 1680 (cyclic CϭO), 1620 (CϭN), 1600 (CϭC),
Antibacterial Activity Evaluation of antibacterial activ-
ity by agar dilution method.10) The standard strains were pro-
cured from the American Type Culture Collection (ATCC),
Rockville, U.S.A., and the pathological strains were procured
from the Department of Microbiology, Madurai Medical Col-
lege and Research Institute, Madurai, India. The antibacterial
activity of the synthesized compounds were screened against
the following bacterial strains: Salmonella typhimurium
ATCC 33068, Pseudomonas aeruginosa ATCC 2853, Salmo-
nella paratyphi B, Proteus vulgaris ATCC 9484, Klebsiella
pneumoniae ATCC 13883, Edwersiella tarda, Bacillus sub-
tilis ATCC 6051. All bacteria were grown on Muller–Hinton
Agar (Hi-media) plates (37 °C, 24 h) then the minimum in-
hibitory concentration (MIC) was considered to be the lowest
concentration that completely inhibited the growth on agar
plates, disregarding a single colony or faint haze caused by
the inoculum. The MIC of the test compounds were com-
pared with the reference drug norfloxacin.
1
1300 (C–N), 1150 (CϭS); H-NMR (CDCl3) d: 3.2—3.5 (s,
6H, –N–(CH3)2), 6.7—7.4 (m, 9H, ArH), 8.6—8.7 (s, 1H,
NH); MS (m/z) 324 (Mϩ). Anal. Calcd for C17H16N4OS, C,
62.96; H, 4.93, N, 17.28. Found : 62.93, H, 4.89; N, 17.32.
PHARMACOLOGY
The synthesized compounds were evaluated for analgesic
anti-inflammatory and antimicrobial acivities. Student-t-test
was performed for all the activities to ascertain the signifi-
cance of the exhibited activities. The test compounds and the
standard drugs were administered in the form of a suspension
(1% carboxyl methyl cellulose as vehicle) in the same route
of administration. Each group consisted of six animals.
Animals The animals were procured from “National Bi-
ological Center,” Madurai, India, and were maintained in
colony cages at 25Ϯ2 °C, relative humidity of 45—55%,
maintained under 12 h light and dark cycle and were fed with
standard animal feed. All the animals were acclimatized for a
week before use.
RESULTS AND DISCUSSION
It has been observed that all the compounds tested showed
significant analgesic activity. The compound A1 with methyl
substitution shown good activity, with the increased
liphophilicity (dimethyl group) compound A2 shown in-
creased activity. Further increase in liphophilicity (diethyl
group). A3 led to further increase in activity. Substitution
with alicyclic amines A4 led to decrease in activity. Place-
ment of alicyclic amines with additional hetero atoms A5,
A6 led to further decrease in activity. Aromatic substitution
A7—A11 shown still lower activity. In general the com-
pounds with aliphatic open chain substitution shown the bet-
ter activity. The compound A3 was found to be the most ac-
tive analgesic agent.
Analgesic Activity7,8) Test for analgesic activity was
performed by “tail-flick technique” using Wistar albino mice
(25—35 g) of either sex selected by random sampling tech-
nique. “Diclofenac sodium” at a dose level of 10 mg/kg and
20 mg/kg was administered as standard 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. The cut off time was
10 s. The percent analgesic activity (PAA) was calculated by
the following formula,
All the compounds showed significant anti-inflammatory
activity, when compared with diclofenac sodium, the com-
pounds A1 and A2 were equipotent and the compound A3
was more potent.
PAAϭ(T2/T1)ϫ100
The results of antibacterial activity reveals that all the test
compounds showed moderate activity against the tested bac-
teria. The compound A2 exhibited good activity against Pro-
teus vulgaris, K. pneumoniae and B. subtilis; The compound
A3 exhibited good activity against S. typhimurium, P. aerugi-
nosa, S. paratyphi B, Proteus vulgaris, E. tarda and Bacillus
subtilis; and the compound A9 exhibited good activity
against S. typhimurium, P. aeruginosa, S. paratyphi B and K.
pneumoniae.
Although the title compounds exhibited potent analgesic
and anti-inflammatory activities, moderate antibacterial ac-
tivity was found. Hence, necessary structural modifications
are planned in the further study to increase the antibacterial
activity. In general in the present study it is observed that
Where T1 is the reaction time(s) before treatment, T2 is the
reaction time(s) after treatment.
Anti-inflammatory Activity Anti-inflammatory activity
was performed by carrageenan-induced paw oedema test in
rats.9) Diclofenac sodium 10, 20 mg/kg was administered as
standard drug for comparison. The test compounds were ad-
ministered at two dose levels (10, 20 mg/kg). The paw vol-
umes were measured using the mercury displacement tech-
nique with the help of a plethysmograph immediately before
and 30 min, 1, 2 and 3 h after carrageenan injection. The per-
cent inhibition of paw oedema was calculated by using the
following formula

1434
Vol. 25, No. 11
Table 1. Physical Data for 1-(2-Phenylquinazolin-3-yl-4-(3H)-one-3-substituted Thioureas
Code
R
Molecular formulaa)
Molecular weightb)
mp (°C)
Yield (%)
A1
A2
N–CH3
Me
C16H14N4OS
C17H16N4OS
310
324
140
178
72
74
–N
Me
Et
A3
A4
–N
C19H20N4OS
C19H15N4OS
352
347
189
205
69
71
Et
A5
A6
C19H18N4O2S
C19H19N5OS
366
351
200
218
72
70
A7
A8
C22H18N4O2S
C21H15N5O3S
402
417
223
210
68
67
A9
C21H15N4O3Cl
C27H20N4OS
406
448
207
231
69
71
Ph
Ph
A10
–N
A11
C20H15N5OS
373
144
66
a) All compounds gave satisfactory elemental analysis (Ϯ0.04% of calculated values). b) Molecular weight determination by mass spectra.
Table 2. Analgesic Activity (Tail-flick Technique)
Percent analgesic activity
Compound
Dose (mg/kg)
30 min
1 h
2 h
3 h
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
10
20
10
20
10
20
10
20
10
20
10
20
10
20
10
20
10
20
10
20
10
20
76Ϯ0.35*
146Ϯ0.38**
79Ϯ0.23*
159Ϯ0.73**
80Ϯ0.58**
165Ϯ0.82***
79Ϯ0.55*
128Ϯ0.25**
70Ϯ0.42*
115Ϯ0.82**
71Ϯ0.23*
113Ϯ0.47**
69Ϯ0.31*
102Ϯ0.12**
69Ϯ0.26*
105Ϯ0.52**
68Ϯ0.70*
97Ϯ0.66*
89Ϯ0.30**
159Ϯ0.26***
91Ϯ0.29***
171Ϯ0.42***
95Ϯ0.62***
173Ϯ0.6***
80Ϯ0.42*
136Ϯ0.52**
80Ϯ0.29*
137Ϯ0.61**
79Ϯ0.76*
129Ϯ0.34**
73Ϯ0.10*
126Ϯ0.35**
74Ϯ0.42*
137Ϯ0.18**
72Ϯ0.26*
123Ϯ0.31**
75Ϯ0.62*
95Ϯ0.40***
165Ϯ0.37***
97Ϯ0.75***
183Ϯ0.38***
115Ϯ0.22***
189Ϯ0.42***
91Ϯ0.75***
144Ϯ0.37**
88Ϯ0.65**
142Ϯ0.41**
90Ϯ0.39***
131Ϯ0.21**
84Ϯ0.7**
132Ϯ0.24**
79Ϯ0.39*
135Ϯ0.80**
80Ϯ0.40**
128Ϯ0.23**
77Ϯ0.18*
143Ϯ0.82**
78Ϯ0.43*
84Ϯ0.38**
132Ϯ0.29**
85Ϯ0.25**
150Ϯ0.5***
87Ϯ0.31**
151Ϯ0.48***
72Ϯ0.65*
116Ϯ0.28**
69Ϯ0.34*
116Ϯ0.20**
68Ϯ0.16*
93Ϯ0.60*
74Ϯ0.41*
101Ϯ0.46**
62Ϯ0.63*
87Ϯ0.22*
65Ϯ0.52*
99Ϯ0.34*
69Ϯ0.24*
103Ϯ0.21**
62Ϯ0.52*
89Ϯ0.19*
2.12Ϯ0.42
70Ϯ0.29*
62Ϯ0.53*
104Ϯ0.42**
66Ϯ0.31*
99Ϯ0.63*
4.41Ϯ0.61
72Ϯ0.19*
141Ϯ0.29**
73Ϯ0.26*
112Ϯ0.34**
3.39Ϯ0.52
86Ϯ0.46*
139.41Ϯ0.32**
136Ϯ0.49**
1.13Ϯ0.29
95Ϯ0.31***
152.85Ϯ0.14***
Control
Diclofenac
10
20
116.63Ϯ0.26**
90.56Ϯ0.6*
Significance levels: * pϽ0.05, ** pϽ0.01 and *** pϽ0.001.

November 2002
1435
Table 3. Anti-inflammatory Activity (Carrageenan Induced Rat Paw Oedema Method)
Percent protection
Compound
Dose (mg/kg)
30 min
1 h
2 h
3 h
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
10
20
10
20
10
20
10
20
10
20
10
20
10
20
10
20
10
20
10
20
10
20
22Ϯ0.42*
30Ϯ0.61**
23Ϯ0.16*
34Ϯ0.46**
26Ϯ0.22**
38Ϯ0.56***
21Ϯ0.42*
33Ϯ0.35**
22Ϯ0.29*
30Ϯ0.53**
21Ϯ0.36*
29Ϯ0.18*
20Ϯ0.24*
31Ϯ0.63**
23Ϯ0.19*
33Ϯ0.65*
19Ϯ0.39*
27Ϯ0.67*
20Ϯ0.05*
26Ϯ0.47*
21Ϯ0.63*
32Ϯ0.13**
4.15Ϯ0.60
23Ϯ0.14*
37Ϯ0.29**
25Ϯ0.26**
50Ϯ0.38***
27Ϯ0.71**
55Ϯ0.39***
30Ϯ0.48***
56Ϯ0.24***
26Ϯ0.72**
42Ϯ0.46***
24Ϯ0.19*
31Ϯ0.19***
53Ϯ0.23***
32Ϯ0.21***
59Ϯ0.29***
37Ϯ0.34***
58Ϯ0.45***
30Ϯ0.28***
44Ϯ0.59***
33Ϯ0.36***
43Ϯ0.49***
29Ϯ0.6***
39Ϯ0.22**
27Ϯ0.49***
44Ϯ0.47***
28Ϯ0.26**
46Ϯ0.50***
23Ϯ0.36**
32Ϯ0.18**
26Ϯ0.92**
35Ϯ0.28**
27Ϯ0.23**
40Ϯ0.55***
3.31Ϯ0.27
22.3Ϯ0.36*
35Ϯ0.41**
20Ϯ0.22*
37Ϯ0.36***
23Ϯ0.19*
35Ϯ0.29**
21Ϯ0.34*
30Ϯ0.13**
20Ϯ0.43*
29Ϯ0.36*
18Ϯ0.15*
24Ϯ0.41*
17Ϯ0.63*
31Ϯ0.24**
19Ϯ0.34*
32Ϯ0.43**
20Ϯ0.17*
25Ϯ0.34*
21Ϯ0.15*
27Ϯ0.59*
19Ϯ0.22*
29Ϯ0.18*
2.47Ϯ0.40
21Ϯ0.26*
36Ϯ0.32**
43Ϯ0.28***
27Ϯ0.24**
36Ϯ0.65*
20Ϯ0.30*
39Ϯ0.32**
24Ϯ0.73**
45Ϯ0.16***
23Ϯ0.52**
29Ϯ0.23*
24Ϯ0.39**
32Ϯ0.36**
25Ϯ0.41**
37Ϯ0.43**
4.19Ϯ0.48
26Ϯ0.52**
49Ϯ0.47***
Control
Diclofenac
10
20
31Ϯ0.35***
53Ϯ0.35***
Significance levels: * pϽ0.05, ** pϽ0.01 and *** pϽ0.001.
Table 4. Antibacterial Activity (Agar Dilution Method) MIC Values (mg/ml)
Drugs/micro
organisms
S. typhimurium
P. aeruginosa
S. paratyphi B Proteus vulgaris
K. pneumoniae
B. subtilis
E. tarda
A1
A2
A3
A4
A5
A6
A7
A8
A9
39.06
19.53
9.76
78.12
156.25
78.12
156.25
156.25
9.76
78.12
19.53
9.76
78.12
78.12
78.12
78.12
156.25
9.76
19.53
19.53
9.76
156.25
78.06
19.53
78.12
78.12
9.76
39.06
9.76
9.76
78.12
9.76
39.06
9.76
9.76
39.06
19.53
9.76
39.06
156.25
156.25
78.12
78.12
78.12
9.76
78.12
19.53
4.88
78.12
156.25
19.53
19.53
78.12
19.53
156.25
156.25
0.018
156.25
78.12
156.25
19.53
156.25
19.53
78.12
78.12
1.22
312.50
156.25
78.12
78.12
156.25
78.12
156.25
19.53
9.76
A10
A11
Norfloxacin
19.53
156.25
2.44
78.12
78.12
0.60
39.06
78.12
0.60
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