Microwave assisted green synthesis of α,ά- bis(substituted-benzylidene)alkanones catalyzed by NbCl5

The catalytic application of NbCl5 as a heterogeneous catalyst was explored for the synthesis ofα, ά- bis (substituted- benzylidene) alkanones under solvent-free conditions. The results showedthat aldehydes bearing electron–releasing substituents on phenyl-ring favored the formation ofproduct in good to excellent yields with reaction times ranging between 3 and 7 min. In addition,furfural, cinamaldehyde, thiophene-2-carbaldehyde and 5-methylthiophene-2-carbaldehyde wereinvestigated in aldol reaction, and the results showed excellent yields.The microwave irradiationgave excellent yields at lower reaction time compared to room temperature (1.5-5 h) and thermalconditions (80 0C, 15-45 min). The microwave irradiation afforded selectively cross aldol products.

کلیدواژه ها:

Niobium pentachloride ، solvent-free ، aryl aldehyde ، microwave irradiation