Starch–sulfuric acid as a bio-supported and recyclable solid acid catalyst for rapid synthesis of α,α′-benzylidene bis(4-hydroxycoumarin) derivatives

Abstract

Starch–sulfuric acid-catalyzed, simple, one pot, solvent-free, environmentally benign synthesis of α,α′-benzylidene bis(4-hydroxycoumarin) derivatives has been achieved by reaction of aromatic aldehydes with 4-hydroxycoumarin. The catalyst is reusable and has remarkable activity. This procedure has several advantages including high yields, short reaction times, easy work-up, and use of an inexpensive, moderately acidic, safe catalyst.