GB699111A - Production of pyrrolinones - Google Patents

Abstract

3 - Aceto - D 3 - pyrrolin - 4 - ol - 2 - one and derivatives of general formula <FORM:0699111/IV (b)/1> where R1, R2 and R3 may be hydrogen, lower alkyl, aryl, substituted aryl, aralkyl or alicyclic groups, are prepared by treatment of an acetoacetic acid amide of general formula <FORM:0699111/IV (b)/2> (where R4 is lower alkyl) with a substance capable of effecting a Claisen condensation whereby an alcohol group is eliminated. The reaction may be conducted in a solvent, such as benzene, toluene or a lower aliphatic alcohol, and particular condensing agents are sodium, potassium, their alkoxides, triphenyl methyl sodium, sodium hydride and sodamide. Typical acetoacetic acid amides include the ethyl esters of acetoacetamido acetic acid, a -acetoacetamido propionic acid and N-phenyl acetoacetamido acetic acid. These amides are prepared from a -amino acetic esters by treatment with diketene in inert organic solvents, benzene, chloroform (or ethanol under cooling conditions). Practical details are given. In examples: (1) 3 - aceto - D 3 - pyrrolin - 4 - ol - 2 - one is prepared from crude ethyl acetoacetamido, acetate in benzene by agitation with methanolic sodium methoxide, then aqueous extraction and acidification when the pyrrolinone is liberated; (2) 3 - aceto - D 3 - 5 - methylpyrrolin - 4 - ol - 2-one is prepared likewise from ethyl acetoacetamido propionate using ethanolic sodium ethoxide; and (3) 3-aceto-1-phenyl-D 3-pyrrolin-4-ol-2-one under the same conditions from the appropriate amide.