Abstract Quaternary salt Ia reacts with sodium and lithium alkoxides to give 1-phenyl-1, 4- dihydropyridine (IIIa) together with unsaturated aldehyde IVa. The reaction mechanism for formation of compound IVa from the primarily arising 2-alkoxy-1-phenyl-1, 2- dihydropyridines is suggested on the basis of products IIIb and IVb, arising from the 3, 4, 5- trideuterio precursor Ib.
