Reactions of enamino keto esters of 1,2,3,4-tetrahydroisoquinoline series with nucleophiles

Abstract

It has been shown that the reaction of the methyl ester of 3-(3,3-dimethyl-1,2,3,4-tetrahydroisoquinolin-1-idene)pyruvic acid with thiosemicarbazide in glacial acetic acid leads to heterocyclization with the formation of 3,3-dimethyl-1-(5-thioxo-1,5-dihydro-1,2,4-triazol-3-ylmethylidenecarbonyl)-1,2,3,4-tetra-hydroisoquinoline, but the interaction with semicarbazide under the same conditions leads to annelation of the pyrrole ring. On condensation of the enamino keto ester with malonodinitrile, the nitrile of 2-cyano-4-dicyanomethylidene-5-(3,3-dimethyl-1,2,3.4-tetrahydroisoquinolin-1-idene)-3-oxo-pentanoic acid is formed.