Acetic acid catalysed solvent‐free synthesis of spiro‐isoxazolo[5,4‐b]pyridines/quinolines by mechano‐chemical grinding

Abstract

A simple and efficient three-component procedure has been developed for the synthesis of a series of spiro-isoxazolo[5,4-b]pyridines/quinolines by one-pot condensation of isatins, 3-methylisoxazol-5-amine and enolizable cyclic carbonyl compounds. The protocol has been accomplished under solvent-free conditions by grinding the components at room temperature in presence of catalytic CH 3 COOH. The described process offers environmentally benign reaction conditions for the synthesis of pharmacologically important spirooxindole fused heterocycles with the advantages ofoperational simplicity, short reaction time and good to excellent yields of isolated pure product.