Studies on Ketene and Its Derivatives. XXXIII. : Acetylation of Ethyl 3-Aminocrotonate

Abstract

Acetylation of ethyl 3-aminocrotonate (I) gives three kinds of monoacetate according to the kind of acetylation agent used. The product of mp 54° is a C-acetate (V) which is obtained in a good yield from I and ketene. The isomer (II) of mp 63° obtained by the treatment of I with acetic anhydride is an N-acetate of I, while the other isomer (III) of mp 108° obtained by the treatment of I with acetyl chloride in pyridine is also an N-acetate of I. II and III are considered to be cis-trans isomers with respect to the enamine carbon-carbon double bond. The structure of II, III, and V is not inconsistent with the result of their decomposition reaction and instrumental analyses.