A new synthesis of naphtho[2,3-C]pyrroles. Conversion of naphtho[2,3-C]thiophene-4,9-diones to naphtho[2,3-C]pyrrole-4,9-diones

A series of 2-substituted-4,9-dihydronaphtho2,3-c]pyrrole-4,9-diones was prepared by the reaction of 4,9-dihydronaphtho2,3-c]thiophene-4,9-diones with primary amines under mild conditions. The presence of halogen in the naphtho2,3-c]thiophene-4,9-dione and the presence of hydroxyl, ether, or tertiary amine functions in the amine reagent do not interfere with the course of the reaction.