A Synthesis of N-Formylenamides of Isoquinoline

Abstract

N-Formylenamides of isoquinoline (6) were obtained from N-[2-(2acyl-4,5-dimethoxyphenyl)ethyl]formamides (5) by cyclization in the presence of catalytic amount of p-toluensulfonic acid. The starting keto formamides (5) were obtained by acylation of a N-[2-(3,4-dimethoxyphenyl)ethyl]formamides (1) with carboxylic acids or their anhydrides in polyphosphoric acid (PPA).