Green approach for the synthesis of thiophenyl pyrazoles and isoxazoles by adopting 1,3-dipolar cycloaddition methodology and their antimicrobial activity.

A variety of N-((1,3-diphenyl-5-aryl-1H-pyrazol-4-yl)sulfonyl)thiophene-2-carboxamides (7) and N-((5-aryl-3-phenylisoxazol-4-yl)sulfonyl)thiophene-2-carboxamides (8) were prepared from (E)-N-(arylethenesulfonyl)thiophene-2-carboxamides (4) adopting 1,3-dipolar cycloaddition of nitrile imines and nitrile oxides generated from araldehyde phenylhydrazones and araldoximes in the presence of iodosobenzene and CTAB followed by oxidation with I in DMSO. The compounds 4f, 7e, 7f, 8e and 8f showed potential antibacterial activity against B. subtilis whereas 8e and 8f exhibited potential antifungal activity against A. niger.