PURPOSE: To obtain the title compound at a high resolution rate by the optical resolution of DL-alanine-DL-madelic acid with the preferential crystallization method in the presence of an amine thereby promoting the crystallization of the desired hardly soluble complex and suppressing the crystallization of the enantiomorphic complex.
CONSTITUTION: DL-Alanine-DL-madelic acid and an amine, e.g. n-propylamine, cyclopentylamine etc., are dissolved in water, and the solution obtained is supersaturated by, e.g. cooling. Then the solution is seeded with the crystals of L-alanine- D-mandelic acid complex or D-alanine-L-mandelic acid complex to crystallize selectively the same sort of the optically active complex. Separation of the complex gives the title compound. The amount of the amine added is preferably 0.1W15% of the supersaturated solution. L-Alanine is useful as one of the components of the amino acid transfusion. D-Mandelic acid is useful as a starting material of cephamandol which is a semisynthetic cephalosporin.
NAGASHIMA KOUJI
AOKI SHIGERU
YASUBOSHI YUUZOU
