Process for the preparation of pyrrolidonecarboxylic acid/metal/amine complexes

Claim 1

A process for the preparation of a pyrrolidone-5-carboxylic acid/metal salt/amine complex of the formula (Ia) in which Me 2+ is a divalent metal cation and, if R 1 and R 2 are each a hydrogen atom, R is one of the following radicals ##STR17## in which b is a number from 10 to 50 and the sum of a and c is a number from 2 to 4, ##STR18## and, if R 1 is a hydrogen atom and R 2 is an alkyl having 1 to 4 C atoms, cyclohexyl, benzyl, 2-aminoethyl or 3-aminopropyl, or if R 1 and R 2 are each an alkyl having 1 to 4 C atoms, cyclohexyl or benzyl, R is an ethylene or propylene radical, and in which R 3 is an alkyl having 2 to 12 C atoms, 2-hydroxyethyl, 2-hydroxypropyl, benzyl, cyclohexyl or cyclopentyl, which comprises reacting 1 mol of a L-glutamic acid ester/metal complex of the formula II ##STR19## in which R 4 is an alkyl having 1 to 4 C atoms, cyclohexyl or benzyl with 1 mol of a diamine of the formula IIIa R.sub.1 --NH--R--NH--R.sub.2 (IIIa) or with 2 mols of a monoamine of the formula IIIb NH.sub.2 --R.sub.3 (IIIb) in a polar organic solvent and in the temperature range from 60° to 180° C., with the elimination of 2 mols of alcohol.