Studies on Nitro Carboxylic Acids. II. Synthesis of α,β-Unsaturated β-Nitro Carboxylic Esters

Synthetic studies on ethyl α,β-unsaturated β-nitrocarboxylates (IV) through two routes are described. Ethyl α-hydroxy-β-nitrocarboxylates (II) obtained by the reactions of ethyl α,β-unsaturated carboxylates with fuming nitric acid or by those of nitroparafins with ethyl glyoxylate, were treated with acetic anhydride to afford ethyl α,-acetoxy-β-nitrocarboxylates (III), which were subsequently converted into IV by treatment with bases used as catalysts. On the other hand, IV was also obtained from ethyl α-chloro-β-nitrocarboxylates derived from the reactions of ethyl α,β-unsaturated carboxylates with nitryl or nitrosyl chloride. The structural assignments of IV were made on the basis of elementary analysis, infrared spectra and its conversion into the corresponding α-methoxy derivatives.