3-Substituted coumarins constitute an important class of coumarins. Apart from their natural occurrence,'several 3-substituted coumarins are known to possess anthelmintic, hypnotic and insecticidal properties. 2 3-Halocoumarins3 (1) also possess insecticidal and fungicidal properties and are useful intermediates for the synthesis of various compounds3 such as 2 and some furocoumarins4 and isocoumestans? Several methods have been reported for ...