Facile Synthesis of 3-Thioxo-3H-benzo[f]chromen-2-yl methanone and 3H-Benzo[f]chromene-3-one Under Solvent Free Condition

Abstract

Many classical routes have been available for the synthesis of coumarin. The Pechmann reaction for the synthesis of coumarin involves the condensation of phenols with β-ketonic esters in the presence of variety of acidic condensing agents such as sul-furic acid, hydrochloric acid and phosphoric acid, phosphorous pentoxide, trifluoroacetic acid and Lewis acids such as ZnCl