PhI(OAc) 2 ‐Mediated One‐Pot Synthesis and their Antibacterial Activity of Flavone and Coumarin Based Isoxazoles Under Mild Reaction Conditions

A facile synthetic method of flavone and coumarin based isoxazoles, and tri‐substituted isoxazoles is reported using aromatic aldehydes, hydroxylamine hydrochloride and O ‐propargyl flavones/coumarin, and internal acetylene via one‐pot condensation and subsequent [3+2] cycloaddition in the presence of phenyliodinediacetate (PIDA) under mild reaction conditions. This methodology is also successfully applied for O ‐propargyl flavone containing heterocyclic ring such as furan and thiophene. One‐pot, high yields (90‐75%), shorter reaction time, easy work‐up and purification by recrystallization are the key advantages of our protocol. All synthesized compounds were tested for antibacterial activity, showed MICconcentration ≥ 1024μg/mL, and compared with standard drugs concentration. MICs data revealed high values against all tested antibiotics which were found in the range of 4 ≥ 4,096 μg mL −1 .