Med Chem Res
with water, brine and dried over sodium sulphate. The
solvent was distilled to afford white solid 4e in 95% yield.
1-((4-methyl-2-p-tolylthiazol-5-yl)methylene)thiosemicar-
bazide (5h) Yield 72 %, m.p. 240 °C (dec.); IR (KBr):
3466, 3430, 3261, 3163, 3009, 2974, 1687, 1645, 1597,
General procedure for synthesis of 1-((4-methyl-2-
1545, 1500, 1368, 1320,1284, 1124, 1001, 841, 801 cm−1
;
phenylthiazol-5-yl) methylene) thio-semicarbazide (5e)
1H NMR (500 MHz, DMSO-d6) δ: 2.45, (s, 3H, Thiazole-
CH3), 2.56 (s, 3H, Ar-CH3), 7.35 (d, J = 6.8 Hz, 2H, H-3′,
H-5′), 7.60 (s, 1H, NH), 7.84 (d, J = 6.8 Hz, 2H, H-2′, H-
6′), 8.25 (s, 1H, NH), 8.35 (s, 1H, NH), 11.48 (s, 1H, N =
CH); 13C NMR (125 MHz, DMSO-d6) δ: 16.0 (Thiazole-
CH3), 21.5 (Ar–CH3), 126.8 (C-2′, -6′), 127.5 (C = N),
130.5 (C-3′, -5′), 130.6 (C-4′), 135.5 (Thiazole C-5), 141.2
(C-1′), 155.1 (Thiazole C-4), 167.1 (Thiazole C-2), 178.5
(C = S); LC–MS, m/z: 291.07 (M + H)+.
The mixture of 4-methyl-2-phenylthiazole-5-carbaldehyde,
4e (2 mmol) and thiosemicarbazide (2.5 mmol) in ethanol
(10 mL) was refluxed for 2 h. After completion of reaction
(TLC) solvent was cooled to room temperature. The product
was filtered, washed with water and recrystallized from
ethanol.
1-((4-methyl-2-phenylthiazol-5-yl)methylene)thiosemicar-
bazide (5e) Yield 66 %, m.p. 230 °C. IR (KBr): 3474,
3432, 3261, 3158, 3018, 2978, 1688, 1647, 1597, 1546,
General procedure for synthesis of 1-(4-methyl-2-
phenylthiazol-5-yl) ethanone (4i)
1491, 1369, 1318, 1284, 1111, 841 cm−1
;
1H NMR
(DMSO-d6, 500 MHz) δ: 2.46 (s, 3H, Thiazole-CH3),
7.50–7.52 (m, 3H, H-3′, H-4′, H-5′), 7.60 (s, 1H, NH),
7.90–7.92 (m, 2H, H-2′, H-6′), 8.28 (s, 1H, NH), 8.35 (s,
2H, NH2), 11.45 (s, 1H, N = CH); 13C NMR (DMSO-
d6,125 MHz) δ: 15.5 (Thiazole-CH3), 128.0 (C-3′, -5′),
129.5 (C = N), 130.9 (C-4′), 132.5 (C-2′, -6′), 132.7 (C-1′),
135.4 (Thiazole C-5), 154.9 (Thiazole C-4), 166.5 (Thiazole
C-2), 177.5 (C = S); LC–MS m/z: 277.1 (M + H)+.
The mixture of thiobenzamide (6.62 mmol) and 3-bromo-
pentane-2,4-dione, (6.62 mmol) was refluxed in ethanol.
After completion of reaction (TLC), solvent was removed
under reduced pressure and the residue was dissolved in
ethyl acetate. Organic layer was washed with sodium
bicarbonate and then water. Organic layer was dried over
sodium sulphate and distilled under vacuum. The product
obtained was purified by column chromatography using
hexane:ethyl acetate (9:1) as eluent.
1-((2-(4-chlorophenyl)-4-methylthiazol-5-yl)methylene)
thiosemicarbazide (5f) Yield 65 %, m.p. 240 °C (dec.); IR
(KBr): 3465, 3428, 3260, 3166, 3010, 2976, 1687, 1646,
1598, 1546, 1502, 1368, 1320, 1284, 1124, 1001, 840, 801
General procedure for synthesis of 1-(1-(4-methyl-2-
phenylthiazol-5-yl) ethylidene) thio-semicarbazide (5i)
cm−1 1H NMR (DMSO-d6, 500 MHz) δ: 2.46 (s, 3H,
;
The mixture of 1-(4-methyl-2-phenylthiazol-5-yl) ethanone,
4i (2 mmol) and thiosemicarbazide (2.5 mmol) in ethanol
(10 mL) was refluxed for 2 h. After completion of reaction
(TLC) solvent was cooled to room temperature. The product
was filtered, washed with water and recrystallized from
ethanol.
Thiazole-CH3), 7.57 (d, J = 8 Hz, 2H, H-3′, H-5′), 8.60 (s,
1H, NH), 7.90 (d, J = 8 Hz, 2H, H-2′, H-6′), 8.28 (s, 1H,
NH), 8.33 (s, 2H, NH2), 11.48 (s, 1H, N = CH); 13C NMR
(DMSO-d6, 125 MHz) δ: 16.0 (Thiazole-CH3), 128.3 (C-2′,
-6′), 128.8 (C = N), 129.9 (C-3′, -5′), 131.9 (C-4′), 135.7
(Thiazole C-5), 135.8 (C-1′), 155.3 (Thiazole C-4), 165.5
(Thiazole C-2), 178.0 (C = S); LC–MS m/z: 311.0 (M +
H)+, m/z: 313.0 (M + H + 2)+.
1-(1-(4-methyl-2-phenylthiazol-5-yl)ethylidene)thiosemi-
carbazide (5i) Yield 66 %, m.p. 230 °C (dec.); IR (KBr):
3470, 3425, 3255, 3145, 3018, 2972, 1679, 1640, 1595,
1-((2-(4-fluorophenyl)-4-methylthiazol-5-yl)methylene)
thiosemicarbazide (5g) Yield 75 %, m.p. 230 °C (dec.);IR
(KBr): 3468, 3434, 3265, 3160, 3012, 2975, 1688, 1649,
1600, 1549, 1500, 1368, 1320,1284, 1124, 1001, 839,
1546, 1491,1311, 1279, 1111, 840 cm−1
;
1H NMR
(DMSO-d6, 500 MHz) δ: 2.38 (s, 3H, Thiazole-CH3), 2.60
(s, 3H, N = CCH3), 7.38–7.42 (m, 4H, H-3′, H-4′, H-5′,
NH), 7.80–7.82 (m, 2H, H-2′, H-6′), 8.45 (s, 1H, NH),
10.51 (s, 1H, NH).13C NMR (DMSO-d6,125 MHz) δ: 18.4
(Thiazole-CH3), 31.1 (N = C–CH3), 128.3 (C-3′, -5′), 129.5
(C-4′), 129.6 (C-2′, -6′), 130.5 (Thiazole C-5), 132.2 (C =
N), 135.8 (C-1′), 157.9 (Thiazole C-4), 167.5 (Thiazole C-
2), 180.5 (C = S); LC–MS m/z: 291.08 (M + H).+
800 cm−1 1H NMR (500 MHz, DMSO-d6) δ: 2.43, (s,
:
3H, Thiazole-CH3), 7.40 (t, J = 7.6 Hz, 2H, H-3′, H-5′),
7.60 (s, 1H, NH), 7.94–7.96 (m, 2H, H-2′, H-6′), 8.28
(s, 1H, NH), 8.35 (s, 1H, NH), 11.46 (s, 1H, N = CH); 13C
NMR (125 MHz, DMSO-d6) δ: 16.6 (Thiazole-CH3), 115.8
(C-3′, -5′), 129.3 (C = N), 129.6 (C-2′, -6′), 130.5 (C-1′),
135.4 (Thiazole C-5), 155.8 (Thiazole C-4), 162.2 (C-4′),
166.9 (Thiazole C-2), 178.5 (C = S); LC–MS m/z: 295.1
(M + H)+.
1-(1-(2-(4-chlorophenyl)-4-methylthiazol-5-yl)ethylidene)
thiosemicarbazide (5j) Yield 65 %, m.p. 240 °C (dec.); IR