Solvent-free Synthesis of 1,2-Disubstituted Derivatives of 1,2- Dihydroisoquinoline, 1,2-Dihydroquinoline and 1,2-Dihydropyridine

A one-pot and efficient approach to the synthesis of dialkyl 2-[1-[(alkoxycarbonyl)anilino]-2(1H)- (isoquinolin-2-yl) (or -quinolin-1-yl or -pyridin-1-yl)]-2-butenedioates is described. This method involves a three-component reaction between isoquinoline, quinoline or pyridine, dialkyl acetylenedicarboxylates and N-phenylcarbamates under solvent-free conditions, without using any catalyst and at room temperature. The mild reaction conditions and good yields of the products exhibit the synthetic advantage of this method.