Multicomponent Synthesis of Unsymmetrical Derivatives of 4-Methyl-Substituted 5-Nitropyridines

The multicomponent reaction of 2-nitroacetophenone (or nitroacetone), acetaldehyde diethyl acetal, ?-dicarbonyl compound, and ammonium acetate in an acetic acid solution allowed the acquisition previously undescribed 4-methyl-substituted derivatives 5-nitro-1,4-dihydropyridine satisfactory yields. oxidation obtained resulted corresponding 2,4-dimethyl-5-nitropyridines. In addition, for first time synthesis unsymmetrical 1,4-dihydropyridines by Hantzsch acetaldehyde, acetal was used as a source acetaldehyde. use more volatile sufficiently reactive this did not lead to controlled 5-nitro-1,4-dihydropyridines. proposed approach 5-nitro-1,4-dihydropyridines their subsequent aromatization into pyridines made it possible obtain hardly accessible substituted 5(3)-nitropyridines.