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

Abstract

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 .