ACID-CATALYZED [4+2]CYCLOADDITION BETWEEN ENAMINES AND BENZYLIDENEANILINES. SYNTHESIS OF 1,2,3,4-TETRAHYDROQUINOLINE DERIVATIVES

Abstract

Abstract The enamines having an α-hydrogen, R1R2N-αCH=βCR3CH3, reacted with a variety of benzylideneanilines to provide the [4+2] cycloadducts, 1,2,3,4-tetrahydroquinoline derivatives, in acetic acid or in methanol containing a catalytic amount of p-toluenesulfonic acid in considerable yield.