Preparation, isolation and properties of diastereomeric copper(II) chelates of the schiff bases of 2-formyl(N,N-dimethylaminomethyl)cymantrene with dipeptides

The optical isomers of 2-formyl( N , N -dimethylaminomethyl)cymantrene (I) can be separated by liquid chromatography of Cu 2+ chelates of the Schiff bases formed from I and a number of dipeptides, in those cases where no racimization of the amino acid residues in the initial dipeptide occurs. Hydrolysis of the chelates gives optically pure enantiomers of I. Under the conditions of the preparation of the chelate from L-Ala-L-Ala (NH 2 C(CH 3 )HCONHC(CH 3 )HCOOH) slow epimerization of the dipeptide into D-Ala-L-Ala takes place. Formation of Cu 2+ chelates of the Schiff bases from L-Ala-L-Ala, D-Ala-L-Ala and L-AlaGly (NH 2 C(CH 3 )HCONHCH 2 COOH) with (+) - and (-) -I proceeds stereospecifically.