Reaction of ethyl ester and nitrile of 5-methyl-2-furancarboxylic acid with mixture of nitric and sulfuric acids

The reaction of 70% HNO with ethyl 5-methyl-2-furancarboxylate in concentrated H2SO4 gave the corresponding 4-nitro derivative and ethyl 5-formyl-2-furancarboxylate. Only 4-nitro derivative, which was converted into amidoxime, was obtained from 5-methyl-2-furonitrile.