Compounds 4a,b. The reaction mixture was boiled for 1 h, after which conc. HCl (25 ml) was added.
The precipitate was separated, dried, suspended in water (50 ml), and solid NaOH added to pH 10. The solution
produced was extracted with ethyl acetate (3 × 100 ml), and dried over Na2SO4. The solvent was evaporated in
vacuum and the residue was chromatographed (SiO2, CHCl3) to give compounds 4a,b.
Compounds 8 and 10 were obtained analogously to compounds 4a,b but with pyridine as the solvent in
place of ethanol.
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4-(4-Fluorophenyl)-2,5-dimethyl-1,3-thiazole (2a). Yield 82%; bp 132-133°C (5 mm Hg). H NMR
spectrum, δ, ppm (J, Hz): 7.56 (2H, dd, J = 8.6, J = 6.0, Harom-3,5); 7.07 (2H, dd, J = 8.6, J = 8.6, Harom-2,6);
2.63 (3H, s, 2-CH3); 2.44 (3H, s, CH3, 5-CH3). Mass spectrum, m/z (Irel, %): 208 [M+1]+ (13), 207 [M]+(100),
206 [M-1]+(23), 166 (63), 133 (23), 122 (27),107 (12). Found, %: C 63.79; H 4.87; N 6.70. C11H10FNS.
Calculated, %: C 63.74; H 4.86; N 6.76.
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4-(2-Fluorophenyl)-2,5-dimethyl-1,3-thiazole (2a). Yield 83%; bp 101-102°C (0.5 mm Hg). H NMR
spectrum, δ, ppm (J, Hz): 7.45 (1H, t, J = 7.7, Harom-4); 7.25 (1H, m, Harom-6); 7.13 (1H, t, J = 7.7, Harom-3); 7.05
(1H, t, J = 9.3, Harom-5); 2.60 (3H, s, 2-CH3); 2.27 (3H, s, 5-CH3). Mass spectrum, m/z (Irel, %): 209 [M+2]+ (11),
208 [M+1]+ (28), 207 [M]+ (100), 206 [M-1]+ (27), 188 (10), 166 (80), 133 (50), 122 (54), 107 (23). Found, %:
C 63.90; H 4.90; N 6.74. C11H10FNS. Calculated, %: C 63.74; H 4.86; N 6.76.
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4-(2-Chlorophenyl)-2,5-dimethyl-1,3-thiazole (2c). Yield 76%; bp 130-131°C (1 mm Hg). H NMR
spectrum, δ, ppm (J, Hz): 7.26 (1H, dd, J = 3.7, J = 3.7, Harom-2); 7.47 (1H, dd, J = 7.4, J = 3.7, Harom-4); 7.30
(1H, dd, J = 7.4, J = 7.4, Harom-6); 7.24-7.28 (1H, m, Harom-5); 2.63 (3H, s, 2-CH3); 2.46 (3H, s, 5-CH3). Mass
spectrum, m/z (Irel, %): 226 [M+3]+ (5), 225 [M+2]+ (39), 224 [M+1]+ (30), 223 [M]+ (100), 222 [M-1]+ (52), 182
(56), 147 (47),13 9 (19), 102 (16). Found, %: C 59.06; H 4.50; Cl 15.95; N 6.20; S 14.41. C11H10ClNS.
Calculated, %: C 59.055; H 4.51; Cl 15.85; N 6.26; S 14.33.
1
2,5-Dimethyl-4-(4-methylphenyl)-1,3-thiazole (2d). Yield 58%; bp 118-119°C (1 mm Hg). H NMR
spectrum, δ, ppm (J, Hz): 7.52 (2H, m, Harom-2); 7.21 (2H, m, Harom-3); 2.65 (3H, s, 2-CH3); 2.47 (3H, d, J = 3.0,
5-CH3); 2.37 (3H, s, CH3-C6H5). Mass spectrum, m/z (Irel, %): 204 [M+1]+ (26), 203 [M]+ (100), 202 [M-1]+ (48),
162 (85), 147 (31), 128 (22), 115 (18), 91 (19). Found, %: C 70.92; H 6.55; N 6.91; S 15.60. C12H13NS.
Calculated, %: C 70.89; H 6.45; N 6.89; S 15.77.
1
4-(4-Methoxyphenyl)-2,5-dimethyl-1,3-thiazole (2e). Yield 63%; bp 141-142°C (1 mm Hg). H NMR
spectrum, δ, ppm (J, Hz): 7.53 (2H, dd, J = 7.7, J = 2.7, Harom-2); 6.92 (2H, dd, J = 7.7, J = 2.7, Harom-3); 3.80
(3H, s, CH3O); 2.62 (3H, s, 2-CH3); 2.43 (3H, d, J = 1.0, 5-CH3). Mass spectrum, m/z (Irel, %): 220 [M+1]+ (35),
219 [M]+ (100), 218 [M-1]+ (30), 204 (19), 178 (84), 163 (99), 135 (33), 102 (16), 91 (29). Found, %: C 65.75;
H 6.06; N 6.40; S 14.69. C12H13NOS. Calculated, %: C 65.72; H 5.975; N 6.39; S 14.62.
2,5-Dimethyl-4-(2-thienyl)-1,3-thiazole (2f). Yield 57%; oil, Rf 0.86 (Silufol UV-254, 10:1
1
benzene–acetone). H NMR spectrum, δ, ppm (J, Hz): 7.19 (1H, dd, J = 3.8, J = 1.3, Hth-5); 7.17 (1H, dd,
J = 5.0, J = 1.0, Hth-3); 6.96 (1H, dd, J = 5.0, J = 3.8, Hth-4); 2.53 (3H, s, 2-CH3); 2.43 (3H, s, 5-CH3). Mass
spectrum, m/z (Irel, %): 197 [M+2]+ ((15), 196 [M+1]+ (19), 195 [M]+ (100), 154 (89), 153 (49), 139 (9), 121
(14), 110 (32), 95 (9). Found, %: C 55.48; H 4.72; N 7.32; S 32.95. C9H9NS2. Calculated, %: C 55.35; H 4.64;
N 7.17; S 32.84.
7-Methoxy-2-methyl-4,5-dihydronaphtho[1,2-d][3,1]thiazole (4a). Yield 41%; oil, Rf 0.6 (Silufol UV-
1
254, 10:1 benzene–acetone). H NMR spectrum, δ, ppm (J , Hz): 7.80 (1H, d, J = 8.4, H-9); 6.78 (1H, dd, J =
8.2, J = 3.0, H-8); 6.74 (1H, d, J = 3.0, H-6); 3.70 (3H, s, CH3O); 2.94 (m, CH2–CH2); 2.70 (3H, s, 2-CH3). Mass
spectrum, m/z (Irel, %): 232 [M+1]+ (11), 231 [M]+ (100), 230 [M-1]+ (28), 216 (44), 189 (9), 175 (8), 158 (6),
147 (23), 145 (11), 115 (9), 103 (9). Found %: C 67.56; H 5.65; N 6.78; S 13.67. C13H13NOS. Calculated, %: C
67.50; H 5.66; N 6.055; S 13.86.
8-Methoxy-2-methyl-4,5-dihydronaphtho[1,2-d][3,1]thiazole (4b). Yield 55%; oil, Rf 0.63 (Silufol
1
UV-254, 10:1 benzene–acetone). H NMR spectrum, δ, ppm (J , Hz): 7.47 (1H, d, J = 3.0, H-9); 7.07 (1H, d,
J = 8.2, H-6); 6.72 (1H, dd, J = 8.2, J = 3.0, H-7); 3.65 (3H, s, CH3O); 2.92 (m, CH2–CH2); 2.70 (3H, s, 2-CH3).
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