Nitropyridines. 2. Hantzsch Synthesis of Nitro- and Dinitropyridines
The interaction of α, β-unsaturated nitro ketones and various enamines leads to the synthesis of 5-nitro-1,4-dihydropyridines containing acetyl, amide, benzoyl, ester, and cyano groups in position 3, and also unsymmetrical 3,5-dinitro-1,4-dihydropyridines. Aromatization of the nitrodihydropyridines was carried out with sodium nitrite in acetic acid.