A series of N-carboethoxy-4-spiro-1, 4-dihydropyridines (1 1) has been prepared via condensation reactions of glutaraldehydes with ammonia or ethyl carbamate. While ammonia gives substantial amounts of 2-amino-1, 2, 3, 4-tetrahydropyridines as well as some 1, 4-dihydropyridines, ethyl carbamate condenses in benzene solution in the presence of catalytic amounts of p-toluenesulfonic acid to give 11 exclusively. The latter ...
