Process for the preparation of l-alpha-amino-eplison-caprolactam and intermediate therefor

Claim 1

A PROCESS FOR PRODUCTION OF L-A-AMINO-E-CAPROLACTAM FROM DL-A-AMINO-E-CAPROLACTAM WHICH CONSISTS ESSENTIALLY OF REACTING DL-A-AMINO-E-CAPROLACTAM WITH SUBSTANTIALLY AN EQUIMOLAR AMOUNT OF L-2-PYRROLIDONE-5-CARBOXYLIC ACID IN SOLUTION IN AN ALKANOL HAVING AT MOST TWO CARBON ATOMS THEREBY PRODUCING AND PRECIPITATING DIFFICULTLY SOLUBLE L-A-AMINO-E-CAPROLACTAM L-2-PYRROLIDONE-5CARBOXYLATE WHILE SIMULTANEOUSLY PRODUCING D-A-AMINOE-CAPROLACTAM WHICH REMAINS IN SOLUTION, SEPARATING THE RESULTANT DIFFICULTLY SOLUBLE L-A-AMINO-E-CAPROLACTAM L-2PYRROLIDONE-5-CARBOXYLATE, CONVERTING SAID DIFFICULTLY SOLUABLE L-A-AMINO-E-CAPROLACTAM L-2-PYRROLIDONE-5-CARBOXYLATE INTO L-2-PYRROLIDONE-5-CARBOXYLIC ACID AND L-A-AMINOE-CAPROLACTAM HYDROCHLORIDE BY REACTING A SUSPENSION OF THE L-E-AMINO-E-CAPROLACTAM L-2-PYRROLIDONE-5-CARBOXYLATE WITH A SOLUTION OF HYDROGEN CHLORIDE IN DIOXAN FILTERING OFF THE L-A-AMINO-E-CAPROLACTAM HYDROCHLORIDIC AND THEN REACTING THE HYDROCHLORIDE IN WATER SOLUTION WITH AN EQUIVALENT OF ALKALI METAL HYDROXIDE, EVAPORATING THE RESULTANT SOLUTION AND DISTILLING FREE L-A-AMINO-E-CAPROLACTAM FROM THE SO-OBTAINED RESIDUE AT REDUCED PRESSURE AND AT A TEMPERATURE OF LESS THAN 120*C., AND RACEMIZING THE AFORESAID D-A-AMINO-E-CAPROLACTAM BY HEATING THE SAME WITH AN ALKALI METAL ALCOHOLATE TO A TEMPERATURE OF 150-165* C., AND RE-USING THE SO-PRODUCED DL-A-AMINOE-CAPROLACTAM AS STARTING MATERIAL FOR THE PRODUCTION OF L-A-CAPROLACTAM BY THE HEREIN-RECITED SEQUENCE OF STEPS.