Synthesis of pyrrolidine and tetrahydroazonine derivatives from N-[bis(ethoxycarbonyl)methyl]tetrahydropyridinium bromide and methyl acetylenedicarboxylate

The reaction of N-methyl-N-(diethoxycarbonyl)methyltetrahydropyridinium bromide with dimethyl acetylenedicarboxylate in the presence of triethylamine at room temperature afforded 1,2-dimethyl 1-ethyl 2-[(3-vinyl-1-methyl-3-phenyl-2- ethoxycarbonyl)pyrrolidin-2-yl]-ethene-1,1,2-tricarboxylate in 25% yield. Its structure was proved by XRD analysis. At cooling to -20°C the pyrrolidine yield signifi cantly decreased and 3,4-dimethyl 2,2-diethyl 1-methyl-7-phenyl-1, 5,8,9-tetrahydro-2H-azonine-2,2,3,4-tetratcarboxylate was obtained in 31% yield. © 2011 Pleiades Publishing, Ltd