The amalgam (Na.Hg) reduction of some 4-substituted-2-amino-3,5-dicyano-6-methoxypyridines 3 results in the formation, in high yields of 3,4-dihydropyridines 2. Highfield 1H and 13C nmr studies provide unambiguous support for the structures proposed. The synthesis of C-4 deuterium labeled dihydropyridine 2c-D, by this procedure, let us understand the role played by this dihydropyridines as intermediates