Carbon-SO3H: An efficient catalyst for the synthesis of biscoumarin under ambient reaction conditions and their in silico studies

Abstract

In this article, we have established a highly promising approach for the synthesis of biscoumarins via domino Knoevenagel–Michael condensation of 4-hydroxycoumarin and aromatic aldehydes in 2:1 ratio using carbon-SO3H as a solid acid catalyst in H2O: EtOH (1:1). This new protocol produced α,ά-benzylidene bis(4-hydroxycoumarin) derivatives in high to excellent yields. For this, carbon-SO3H solid acid catalyst has been prepared from glycerol and sulfuric acid and characterized by FT-IR, SEM, TGA, and X-ray diffraction methods. This approach has several advantages such as high atom-economy (96.05%), excellent yields (88-100%), no need of further purification techniques, that is, column chromatography, easy workup, less reaction time, cost-effective, avoid the use of hazardous solvents, recyclability of catalyst, etc. Moreover, molecular docking studies have been performed on selected proteins methylenetetrahydrohyrofolate reductase (MTHFR) and cytochrome P450 3A4 (CYP3A4) to identify the potency of the synthesized compounds (3a–j). Among the synthesized compounds 3i, 3e, and 3b showed the highest docking score against both the proteins.