Lithium Perchlorate and Lithium Bromide Catalysed Solvent Free One Pot Rapid Synthesis of 3-Carboxycoumarins under Microwave Irradiation

Abstract
Reaction of 2-hydroxy or 2-methoxy substituted benzaldehydes or acetophenones with Meldrum's acid in the presence of a catalytic amount of LiClO4 or LiBr without solvent under microwave irradiation afforded 3-carboxycoumarins in excellent yields.