SYNTHESIS, CHARACTERIZATION, AND ANTIBACTERIAL ACTIVITY
705
upon stirring. The reaction mixture was heated at 50–
60°C for 3.5–4 h followed by stirring at room tem-
perature for 24 h. The reaction mixture was filtered off
to give the corresponding thiourea that was crystallized
from either ethanol or glacial acetic acid.
1-Allyl-3-(pyridin-2-yl)thiourea (4e). Yield 40%,
mp 98–100ºC. IR spectrum, ν, cm–1: 3229 (N–H), 2956
(Ar–CH), 1598 and 1541 (Ar–C=C), 1452 (N–H),
1
1331 (C–N), 1194 (C=S). H NMR spectrum, δ, ppm:
4.29–4.36 m (2H, –CH2), 5.16–5.30 m (2H, =CH2),
5.95–6.04 m (1H, =CH), 6.96-8.18 m (4H, Ar–H),
10.61 s (1H, Ar N–H), 11.86 s (1H, N–H). 13C NMR
spectrum, δ, ppm: 47.76, 112.37, 116.36, 118.01,
133.24, 138.65, 145.60, 153.56, 179.60. M 194.0 [M +
H]+. Found, %: C 55.67, H 5.66, N 19.17. C9H11N3S.
Calculated, %: C 55.93, H 5.74, N 19.74.
1-Allyl-3-phenylthiourea (4a). Yield 50%, mp
101–103°C. IR spectrum, ν, cm–1: 3348 (N–H); 3006
(Ar–CH); 1589 and 1533 (ArC=C); 1443 (N–H) ; 1387
(C–N); 1186 (C=S). 1H NMR spectrum, δ, ppm: 4.17–
4.19 d (2H, –CH2); 5.09–5.22 m (2H, =CH2); 5.85–
5.95 m (1H, =CH); 7.06–7.44 m (5H, Ar–H); 7.66 s
(1H, ArN–H); 9.45 s (1H, N–H). 13C NMR spectrum,
δ, ppm: 47.62, 117.04, 125.25, 127.2, 130.12, 133.27,
136.15, 180.41. M 193 [M + H]+. Found, %: C 62.16,
H 6.15, N 14.03. C10H12N2S. Calculated, %: C 62.46,
H 6.29, N 14.57.
Cyclization of thioureas in presence of HCl (5a–
5c) (general procedure). To a solution of thiourea
(1 mmol) in ethanol was added ethanolic HCl (4 mmol).
The mixture was refluxed for 2–2.5 h, cooled down
and neutralized with aqueous NaHCO3 to make the
product to precipitate. The solid was filtered off,
repeatedly washed with distilled water and crystallized
from ethanol.
1-Allyl-3-(4-chlorophenyl)thiourea (4b). Yield
56%, mp 97–99ºC. IR spectrum, ν, cm–1: 3233 (N–H),
3052 (Ar–CH), 1599 and 1548 (Ar–C=C), 1490 (N–H),
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1411 (C–N), 1091 (C=S). H NMR spectrum, δ, ppm:
5-Methyl-N-phenyl-4,5-dihydrothiazol-2-amine
(5a). Yield 75%, mp 114–116ºC. IR spectrum, ν, cm–1:
3466 (N–H), 3027 (Ar–CH), 1631 and 1585 (Ar–
C=C), 1491 (N–H), 1318 (C–N). 1H NMR spectrum, δ,
ppm: 1.31–1.32 d (3H, –CH3), 3.40–3.59 d.d (1H,
–CH), 3.84–3.96 m (2H, –CH2), 6.89–7.44 m (4H, Ar–H),
8.78 br.s (1H, N–H). 13C NMR spectrum, δ, ppm:
21.11, 44.40, 63.91, 118.64, 121.39, 128.53, 144.51,
156.28. M 193.0 [M + H]+. Found, %: C 64.25, H 6.15,
N 15.07. C10H12N2S. Calculated, %: C 62.46, H 6.29,
N 14.57.
4.25 s (2H, –CH2), 5.15–5.20 d.d (2H, =CH2), 5.81–
5.91 m (1H, =CH), 6.13 br.s (1H, Ar N–H), 7.19–7.39
m (4H, Ar–H), 8.83 br.s (1H, N–H). 13C NMR spec-
trum, δ, ppm: 47.63, 117.40, 126.53, 130.16, 132.6,
133.02, 134.81, 180.42. M 227 [M + H]+. Found, %: C
52.76, H 4.69, N 11.98. C10H11ClN2S. Calculated, %:
C 52.97, H 4.89, N 12.36.
1-Allyl-3-p-tolylthiourea (4c). Yield 42%, mp 98–
100ºC. IR spectrum, ν, cm–1: 3295 (N–H), 3010 (Ar–CH),
1586 and 1532 (Ar–C=C), 1449 (N–H), 1315 (C–N),
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1191 (C=S). H NMR spectrum, δ, ppm: 2.29 s (3H,
N-(4-Chlorophenyl)-5-methyl-4,5-dihydrothiazol-
2-amine (5b). Yield 63%, mp 116–118ºC. IR
spectrum, ν, cm–1: 3088 (Ar–CH), 1625 and 1581 (Ar–
C=C), 1485 (N–H), 1320(C–N). 1H NMR spectrum, δ,
ppm: 1.30–1.31 d (3H, –CH3), 3.54–3.57 d (1H, –CH),
3.84–3.95 m (2H, –CH2), 7.24–7.43 m (4H, Ar–H),
8.91 br.s (1H, N–H). 13C NMR spectrum, δ, ppm:
21.04, 44.45, 63.83, 120.27, 125.01, 128.35, 143.58,
156.58.M 227.0 [M + H]+. Found, %: C 54.70, H 4.91,
N 12.60. C10H11ClN2. Calculated, %: C 54.97, H 4.89,
N 12.36.
–CH3), 4.14 s (2H, –CH2), 5.08–5.20 m (2H, =CH2),
5.84-5.93 m (1H, =CH), 7.10–7.27 m (4H, Ar–H), 7.60
br.s (1H, Ar N–H), 9.39 br.s (1H, N–H). 13C NMR
spectrum, δ, ppm: 21.08, 47.81, 116.99, 125.69, 130.83,
133.11, 133.33, 137.78, 180.90. M 207 [M + H]+.
Found, %: C 63.66, H 6.53, N 13.00. C11H14N2S.
Calculated, %: C 64.04, H 6.84, N 13.58.
4-(3-Allylthioureido) benzoic acid (4d). Yield
59%, mp 180–182ºC. IR spectrum, ν, cm–1: 3363 (N–H),
3016 (Ar–CH), 1693 (C=O), 1606 and 1532 (Ar–
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C=C), 1420 (N–H), 1306 (C–N), 1171 (C=S). H
5-Methyl-N-p-tolyl-4,5-dihydrothiazol-2-amine
(5c). Yield 57%, mp 103–105ºC. IR spectrum, ν, cm–1:
3103 (Ar–CH), 1651 and 1607 (Ar–C=C), 1505 (N–H),
NMR spectrum, δ, ppm: 4.16 s (2H, –CH2), 5.11–5.24
m (2H, =CH2), 5.86–5.95 m (1H, =CH), 7.63–7.89 m
(4H, Ar–H), 8.13 s (1H, Ar N–H), 9.88 s (1H, N–H),
12.46 br.s (1H, O–H). 13C NMR spectrum, δ, ppm:
46.02, 115.99, 121.02, 125.24, 129.96, 134.36, 143.73,
166.94, 180.21. M 237.0 [M + H]+. Found, %: C 54.56,
H 5.24, N 10.00. C11H12N2O2S. Calculated, %: C 54.9,
H 5.12, N 10.26.
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1307 (C–N). H NMR spectrum, δ, ppm: 1.42–1.44 d
(3H, –CH3 with aromatic ring), 2.33 s (3H, –CH3 on
thiazole ring), 3.35–3.39 d.d (1H, –CH), 3.78–3.88 m
(2H, –CH2), 6.99–7.12 m (4H, Ar–H), 7.66 br.s (1H,
NH). 13C NMR spectrum, δ, ppm: 20.32, 20.86, 43.17,
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 86 No. 3 2016