Tautomerism of Ethyl 3-Oxobutyrate and Its 2-Alkyl Derivatives

Abstract

Effects of substituents, solvents, concentration, and temperature on tautomerization of ethyl 3-oxobutyrate and its 2-alkyl derivatives were studied. The tautomeric equilibria of ethyl 3-oxobutyrate depend mainly on the polarity and hydrogen-bond donor acidity of solvents. On the other hand, the tautomerization of the 2-methyl derivative is independent of the solvent. Keto-enol interconversion of the keto esters shifts from the keto form to the enol form with an increase in temperature. In addition, rate constants for interconversion from the keto to the enol of ethyl 2-butyl-3-oxobutyrate were determined using H-D exchange reaction.