Addition of Some Enamino Esters to 3-Substituted Coumarins

Abstract

Abstract The addition of the enamino esters 1a, b to several coumarins with electron-withdrawing 3-substituents 2 yielded 3 and 4, whereas ethyl 3-amino-2-butenoate (1c) reacted surprisingly with its C-4 to give either an adduct 8 or pyrido [3,4-c] chromene 9.