Multicomponent synthesis of 4-unsubstituted 5-nitropyridine derivatives

Abstract

Multicomponent reaction of 2-nitroacetophenone, urotropine (or paraformaldehyde), β-dicarbonyl compound and ammonium acetate afforded five new 4-unsubstituted 5-nitro-6-phenyl-1,4-dihydropyridine derivatives, oxidation of which provided the corresponding 5-nitro-6-phenylpyridines. The proposed approach for the synthesis of 4-unsubstituted 5-nitro-6-phenyl-1,4-dihydropyridines and their subsequent aromatization into pyridines made it possible to reduce the total reaction time by more than 200 times and the overall yield of 5-nitro-6-phenylpyridine by 2 times compared with the known methods.