Synthesis of amide-linked benzazolyl isoxazoles adopting green methods and evaluation as antimicrobials

Some new benzoxazolyl isoxazoles, benzothiazolyl isoxazoles and benzimidazolyl isoxazoles connected by amide bonds (7-9) were prepared from N-benzazolylcarbamoylmethylcinnamamides (1-3) adopting eco-friendly synthetic methodologies. In fact, cycloaddition of nitrile oxide generated from araldoxime using iodosobenzene and cetyltrimethylammonium bromide to 1-3 followed by treatment with iodine in dimethyl sulfoxide led to the formation of title compounds with good yields and in shorter reaction times. The structures of all the synthesized compounds were confirmed by spectral parameters, viz, IR, NMR, and mass spectra and were assayed for antimicrobial activity. Among all the tested compounds, 8a and 8c displayed excellent antibacterial activity, whereas 9a and 9c showed promising antifungal activity.