Efficient Synthesis of Spirooxindole-Pyrrolo[1,2-a]Pyrazin-2-ones via Ionic Liquid-Ultrasonication

Abstract

A sustainable and efficient synthesis of new spiro[pyrrolo[1,2-a]pyrazin]-2-ones was developed using N-protected isatins, N-substituted piperazines, and chalcones under ultrasonic conditions in [C12C12BIm]Br, a green ionic liquid. The reaction proceeds through a 1,3-dipolar cycloaddition between an in situ generated azomethine ylide and chalcone. This approach offers several advantages, including its environmental friendliness, mild reaction conditions, and the recyclability of the ionic liquid.