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Chapter 3
Synthesis of trisubstituted pyrazoles/isoxazoles
3-Cyclopropyl-5-(methylthio)-N-o-tolylisoxazole-4-carboxamide 6j. White solid;
R f 0.67 (8:2 hexane-EtOAc); mp 155-157 o C; IR (KBr): 3285, 3145, 3091, 3003,
2964, 2831, 1639, 1589, 1413, 1237, 1029, 761 cm -1 ; MS (m/z): 288 (M + ); Anal.
Calcd for C 14 H 13 F 2 N 3 OS: C, 62.48; H, 5.59; N, 9.71; Found: C, 62.49; H, 5.57; N,
9.72.
3-Cyclopropyl-N-(4-ethylphenyl)-5-(methylthio)isoxazole-4-carboxamide 6k.
White solid; R f 0.72 (8:2 hexane-EtOAc); mp 160-162 o C; IR (KBr): 3282, 3143,
3093, 3013, 2952, 2822, 1631, 1586, 1418, 1241, 1031, 839 cm -1 ; MS (m/z): 302
(M + ); Anal. Calcd for C 16 H 18 N 2 O 2 S: C, 63.55; H, 6.00; N, 9.26; Found: C, 63.57; H,
6.03; N, 9.24.
N-(5-chloro-2-methoxyphenyl)-3-cyclopropyl-5-(methylthio)isoxazole-4-carboxamide
6l. White solid; R f 0.65 (8:2 hexane-EtOAc); mp 220-222 o C; IR (KBr): 3291,
3139, 3092, 3005, 2968, 2842, 1639, 1582, 1425, 1231, 1029, 872, 739 cm -1 ; MS
(m/z): 338 (M + ); Anal. Calcd for C 15 H 15 ClN 2 O 3 S: C, 53.17; H, 4.46; N, 8.27; Found:
C, 53.19; H, 4.43; N, 8.29.
N-(2,5-dichlorophenyl)-3-cyclopropyl-5-(methylthio)isoxazole-4-carboxamide
6m. White solid; R f 0.73 (8:2 hexane-EtOAc); mp 202-204 o C; IR (KBr): 3281, 3139,
3081, 3019, 2951, 2829, 1632, 1584, 1426, 1238, 1037, 894, 763 cm -1 ; MS (m/z): 343
(M + ); Anal. Calcd for C 14 H 12 Cl 2 N 2 O 2 S: C, 48.99; H, 3.52; N, 8.16; Found: C, 48.97;
H, 3.53; N, 8.12.
3-Cyclopropyl-N-(2,5-dimethylphenyl)-5-(methylthio)isoxazole-4-carboxamide
6n. White solid; R f 0.58 (8:2 hexane-EtOAc); mp 208-210 o C; IR (KBr): 3287, 3139,
3091, 3007, 2959, 2839, 1634, 1594, 1419, 1243, 1029, 882, 742 cm -1 ; MS (m/z): 302
(M + ); Anal. Calcd for C 16 H 18 N 2 O 2 S: C, 63.55; H, 6.00; N, 9.26; Found: C, 63.57; H,
6.03; N, 9.24.
3-Cyclopropyl-N-(3,4-difluorophenyl)-5-(methylthio)isoxazole-4-carboxamide 6o.
White solid; R f 0.67 (8:2 hexane-EtOAc); mp 223-225 o C; IR (KBr): 3292, 3139,
3089, 3008, 2964, 2842, 1632, 1591, 1417, 1239, 1041, 839, 779 cm -1 ; MS (m/z): 310
(M + ); Anal. Calcd for C 14 H 12 Cl 2 N 2 O 2 S: C, 54.19; H, 3.90; N, 9.03; Found: C, 54.17;
H, 3.93; N, 9.02.
Department of Chemistry Saurashtra university, Rajkot-360005 108