Structural Elucidation of Z- and E- Isomers of 5-Alkyl-4-ethoxycarbonyl-5-(4`-chlorophenyl)-3-oxa-4-pentenoic Acids

Abstract: Z- and E-isomers of 5-alkyl-4-ethoxycarbonyl-5-(4`-chlorophenyl)-3-oxa-4-pentenoic acids were prepared via the condensation of p-chloroacetophenone and/or pchloropropiophenone with diethyl-2,2`-oxydiacetate in the presence of sodium hydride as a basic catalyst. The Z-isomers of 2a and 2b were found to be predominant. The behaviour of the corresponding anhydrides towards the action of hydrazine, phenylhydrazine, primary aromatic amines, hydrocarbons and ethanolysis has also been investigated. The structures and configurations of the products have been elucidated by chemical and spectroscopic means.