Averrhoa bilimbi in Organic Transformation:A Highly Efficient and Green Biosurfactant for the Synthesis of Multi-Functional Chromenes and Xanthenes

A simple, clean and efficient one-pot three-component synthesis of multi-functional chromene and xanthene derivatives has been developed in this study in the presence of a catalytic amount of Brǿnsted acidic-type biosurfactant bilimbi fruit extract (BFE) under elevated temperature condition. BFE is an unprocessed micellar catalyst that works well in an ethanolic aqueous medium. Employment of ethanol as a cosurfactant enhances catalytic performance of BFE as a biosurfactant. The presence of micelles in the reaction medium was detected using light microscopy and their critical micelle concentration was measured by electrical conductivity method. Some new derivatives of chromene and xanthene are reported here. This novel catalytic medium obtained from an environmentally renewable resource is highlyadvantageous because of its non-toxicity, higher efficiency, operational simplicity, bio-compatibility as well as absence of any tedious work-up or column chromatography and thus no waste generation. Here, we also signify the ‘greenness and sustainability’ of the present protocol on the basis of EcoScale metric which validates the practical application of the synthetic procedure.