Isoxazole is a class of heterocyclic compounds having a remarkable number of applications and has been demonstrated to be very versatile building blocks in organic synthesis.
Two series of N-(4-aryl)-5-methylisoxazol-4-carboxamide and N-(4-aryl)-3-methylisoxazol-4-carboxamide were synthesized and spectroscopic studied to investigate the variation reaction on the substutents phenyl ring. The isoxazole derivatives were prepared from the reaction 5-methylisoxazole-4-carbonyl chloride or 3-methylisoxazole-4-carbonyl chloride and substituted anilines in good yields.
The SCS on C-13 NMR studies on the series of N-(4-aryl)-5-methyl- isoxazol-4-carboxamide showed that the aryl substituent effect on isoxazole’s C5 via long distance Hammett substituent effect (slope = +1.3, r2 = 0.94).
N-(4-aryl)-3-methylisoxazol-4-carboxamide was first synthesized and characterized by means of melting point, elemental analysis, IR, UV, EI-MS, 1H NMR spectrum and 13C NMR spectrum analysis.
