Method of preparing synthetic dl-3 monoamide of 1-aminoglutaric acid (dl-glutamine)

Claim 1

IN THE PROCESS OF PRODUCING DL-GLUTAMINE BY PREPARING DI-PHTHALYLGUTAMIC ACID, CONVERTING SAID DLPHTHALYLGLUTAMIC ACID INTO DL-PHTHALYLGUTAMIC ANHYDRIDE, TRANSFORMING SAID DL-PHTHALYLGLUTAMIC ANHYDRIDE INTO DLPHTHALYLGLUTAMINE, AND HYDROLYZING SAID DI-PHATHALYLGLUTAMINE TO LIBERATE DL-GLUTAMINE, THE IMPROVEMENT IN THE STEP OF PREPARING THE PHTHALYLGLUTAMIC ANHYDRIDE WHICH COMPRISES FORMING SAID ANHYDRIDE BY THE ADDITION OF ACETIC ANHYDRIDE TO THE REACTION MIXTURE RESULTING FROM THE REACTION OF GLUTAMIC ACID WITH PHTHALIC-ANHYDRIDE, AND THE IMPROVEMENT IN THE HYDROLYSIS STEP WHICH COMPRISES TRANSFORMING THE DL-PHTHALYLGLUTAMINE INTO THE POTASSIUM SALT, SUBJECTING SAID SALT TO THE ACTION OF HYDRAZINE HYDRATE, PRECIPITATING THE PHTHALYLHYDRAZIDE THUS FORMED WITH ACETIC ACID TO FORM DL-GLUTAMINE ACETATE, AND RECOVERING DLGLUTAMINE FROM SAID DL-GLUTAMINE ACETATE.