1044
Suresh S Patil et al.
cooled and then poured into dil. HCl (50 ml). The antifungal griseofulvin were also screened under simi-
separated solid was filtered, washed with water, and lar condition for comparison.
recrystallized from ethanol, Yield: 87%, m. p. 268◦C.
The results indicate that the compounds 2e, 2f, 3e, 3f,
(Found: C, 63.75; H, 5.09; N, 12.39 C18H17O2N3S 4e and 4f exhibited good antimicrobial activity against
requires: C, 63.70; H, 5.05; N, 12.38%); IR(KBr)cm−1: above bacteria and fungal species, while the compounds
3460–3340 (oxime -OH), 1672 (cyclic amide C=O), 2d, 3a, 3d and 4d have moderate antimicrobial activi-
1620 and 1612 (C=N)cm−1; 1H NMR: δ 2.12 (3H, s, - ty against both Gram +ve and −ve bacteria and fungal
N=C-CH3), 2.32 (3H, s, Ar-CH3), 4.16 (2H, s, S-CH2), species (table 1).
7.03–8.11(8H, m, Ar-H), 10.42 (1H, s, -OH) ppm;
The generalization can be made from these observa-
MS (m/z): 339(M+), 324, 308, 248, 235(100%), 104, tions that the compounds with substituent groups like
91; 13C NMR: 17.3, (CH3-C=N), 24.3 (Ar-CH3), 32.1 -Cl and -Br enhance the antimicrobial activity than the
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(S-CH2-), 120.9 (C9), 120.8 (C2 and C6 ), 121.7 (C8), other substituted compounds.
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127.2 (C6), 128.8 (C5), 129.2 (C1 ), 129.6 (C3 and C5 ),
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134.0 (C7), 134.1 (C4 ), 147.1 (C10), 161.1 (C4), 163.6
2.5 Analytical data of synthesized compounds
(C2), 169.0 (C=N-OH).
Compounds 3b to 3f were prepared by operating
same method.
2.5a 3-(2-Methylphenyl)-2-[(2-oxopropyl)sulfanyl]
quinazolin-4(3H)-one (2b): Yield: 76%; m.p. 100◦C;
(Found: C, 66.65; H, 4.95; N, 8.69 C18H16O2N2S
requires: C, 66.64; H, 4.97; N, 8.64%); IR (KBr) cm−1:
1718 (C=O), 1676 (cyclic amide C=O), 1612(C=N);
1H NMR (CDCl3): δ 2.51 (3H, s, -COCH3), 2.42 (3H,
s, Ar-CH3), 4.91 (2H, s, S-CH2), 7.03–8.11(8H, m, Ar-
H) ppm. 13C NMR: 15.2 (Ar-CH3), 29.6 (CH3-C=O),
2.3 2-[2ꢁ-(O-phenylcarbamoylimino) propylidene
thio] 3-(p-methylphenyl) quinazolin-4(3H)one (4a)
The equimolar mixture of 3a (0.20 g, 0.0006 mol) and
phenylisocynate (0.07 g, 0.0006 mol) in THF (10 ml)
was heated on a steam bath at 70◦C for 2 h, cooled
and the separated solid was filtered and recrystal-
lized from ethanol, Yield: 90%, m. p. 235◦C. (Found:
C, 65.52; H, 4.82; N, 12.25 C25H22O3N4S requires:
C, 65.49; H, 4.84; N, 12.22%); IR(KBr) cm−1: 1710
(carbamate C=O), 1676 (cyclic amide C=O), 1610
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37.6 (S-CH2-C=O), 120.1 (C10), 122.2 (C6 ) 122.6
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(C8), 124.4 (C4 ), 125.8 (C5 ), 127.6 (C6), 128.2(C3 ),
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128.9(C5), 135.1(C2 ), 135.6 (C1 ), 136.9 (C7), 147.4
(C9), 161.1 (C4), 163.8 (C2), 201.4 (CH3-C=O).
1
and 1612 (C=N) cm−1; H NMR: δ 2.15 (3H, s,
2.5b 3-(3-Methylphenyl)-2-[(2-oxopropyl)sulfanyl]
quinazolin-4(3H)-one (2c): Yield: 81%; m.p. 145◦C;
(Found: C, 66.65; H, 4.95; N, 8.69 C18H16O2N2S
requires: C, 66.64; H, 4.97; N, 8.64%); IR (KBr) cm−1:
1720 (C=O), 1674 (cyclic amide C=O), 1612(C=N);
1H NMR (CDCl3): δ, 2.3 (3H, s, -COCH3), 2.5 (3H,
s, Ar-CH3), 4.0 (2H, s, S-CH2), 7.1–8.0(8H, m, Ar-H)
ppm. 13C NMR: 23.7 (Ar-CH3), 29.3 (CH3-C=O), 36.9
-N=C-CH3), 2.35 (3H, s, Ar-CH3), 4.12(2H, s, S-CH2),
7.20–8.11(13H, m, Ar-H), 8.61 (1H, s, -NH) ppm; MS
(m/z): 458(M+), 367, 366, 322(100%), 235, 223, 136,
91, 77; 13C NMR: 23.1, (CH3-C=N), 24.3 (Ar-CH3),
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24.9 (S-CH2-), 119.9 (C9), 121.5 (C2 and C6 ), 121.8
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(C2 and C6 ), 122.7 (C8),124.6 (C4 ), 127.2 (C6), 128.4
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(C5), 127.2 (C1 ), 129.0 (C3 and C5 ), 129.3 (C3 and
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(S-CH2-C=O), 118.2(C6 ), 121.1 (C10), 122.1 (C8),
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ꢁꢁ
C5 ), 133.9 (C7), 134.0 (C4 ), 135.8 (C1 ), 146.9 (C10),
151.8 (O-C=O-NH), 161.1 (C4), 163.2 (C2), 164.5
(-C=N-O).
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123.4 (C2 ), 124.6 (C4 ), 128.2(C5 ), 127.3 (C6), 128.9
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(C5), 135.2 (C1 ), 138.8 (C3 ), 134.9 (C7), 147.9 (C9),
162.0 (C4), 164.1 (C2), 200.4 (CH3-C=O).
Compounds 4b to 4f were prepared by operating
same method.
2.5c 3-(4-Methoxyphenyl)-2-[(2-oxopropyl)sulfanyl]
quinazolin-4(3H)-one (2d): Yield: 78%; m.p. 168◦C;
(Found: C, 63.45; H, 4.67; N, 8.29 C18H16O3N2S
requires: C, 63.51; H, 4.74; N, 8.23%); IR (KBr) cm−1:
1720 (C=O), 1676 (cyclic amide C=O), 1610(C=N);
1H NMR (CDCl3): δ 2.13 (3H, s, -COCH3), 3.24 (3H,
s, Ar-OCH3), 3.80 (2H, s, S-CH2), 7.21–8.12(8H, m,
Ar-H) ppm. 13C NMR: 29.9 (CH3-C=O), 38.1 (S-CH2-
2.4 Antimicrobial activity
The antimicrobial screening of synthesized compounds
was carried out by paper disc diffusion method at
100 ppm against Gram +ve bacteria B. substilis, S.
aureus and Gram −ve bacteria like E. coli, P. vul-
garis. The antifungal activity of the compounds was
assayed using fungal species Aspergillus niger and
Phytophora. Standard antibacterial streptomycin and
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C=O), 56.7 (Ar-OCH3), 114.4 (C3 and C5 ), 120.7
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(C10), 121.9 (C8), 122.6(C2 and C6 ), 125.3 (C1 ), 127.1