Alkaline Hydrolysis of 4-Alkyl Pyrazolidinones at High Temperatures

Abstract

The hydrolytic stability of a series of 4-alkylpyrazolidin-3-ones was investigated at 100°C. The reaction product for the parent compound, l-phenylpyrazolidin-3-one, was identified as N-phenyl-N-(β-carboxyethyl)hydrazine. The reaction is base catalyzed and reversible, with an activation energy of 15.4 kcal/mole for the parent compound. The rate and the extent of reaction decrease as the steric bulk of the 4-alkyl substituent increases. Thus, for the parent compound, about a fourth of the starting material remains when the system has reached equilibrium; for the tert-butyl substituent, about three-fourths of the starting material remains at equilibrium.