A convenient one-pot synthesis of 4-hydroxycoumarin, 4-hydroxythiocoumarin, and 4-hydroxyquinolin-2(1H)-one

An improved one-pot synthesis of 4-hydroxycoumarin. 4-hydroxythiocoumarin, and 4-hydroxyquinolin-2(1H)-one from 2-hydroxyacetophenone, 2-mercaptoacetophenone, and 2-aminoacetophenone, respectively, is described. The synthetic strategies involve the acylation and internal ring cyclization. This method is readily amenable to large-scale synthesis of 4-hydroxycoumarin, 4-hydroxythiocoumarin, and 4-hydroxyquinolin-2(1H)-one derivatives in high yields.