Convenient synthesis and antimicrobial activity of new 3-substituted 5-(benzofuran-2-yl)-pyrazole derivatives.

The reaction of ethyl 4-(benzofuran-2-yl)-2,4-dioxobutanoate 2 with two moles of hydrazine hydrate afforded 5-(benzofuran-2-yl)-1H-pyrazole-3-carbohydrazide 4a, while its reaction with equimolar amount of phenylhydrazine gave ester 3b which then converted to 5-(benzofuran-2-yl)-1-phenyl-1H-pyrazole-3-carbohydrazide 4b. Various new compounds such as imides 5 and 6, acyl hydrazones 7 and 8, bi-pyrazoles 9-12, and 1,3-thiazole derivatives 14 and 15 were prepared from carbohydrazide derivatives 4a, b. The new compounds are tested for their antimicrobial activity. Compounds 2, 5, 7, and 8 showed antifungal activities against C. albicans. Also, compounds 2, 6, 8, and 15 showed antibacterial activities.