Syntheses with nitriles, LXXXVIII; cyanonitropropenides - Synthons for the preparation of nitropyridines

Article abstract of DOI:10.1055/s-1991-26585

Nitroacetonitrile reacts with triethyl orthoformate, orthoacetate and orthopropionate, respectively in presence of pyridine to the pyridinium salts of 1,3-dicyano-1,3-dinitro-2-propen-1-ides. With ethoxymethylenemalononitrile nitroacetonitrile yields 1,1,3-tricyano-3-nitropropenide, which can be cyclized with sodium methoxide or ethoxide to 2-alkoxy-6-amino-3-cyano-5-nitropyridines. Ether cleavage of the latter leads to 6-amino-3-cyano-5-nitro-2(1H)-pyridone, subsequent chlorination gives the corresponding 2-chloropyridine, suitable for nucleophilic substitutions. By hydrolysis of the nitrile group 6-amino-5-nitro-3-pyridine-carboxylic acid derivatives are obtained.