| abstract |
A process for the preparation of optically pure diastereoisomers of tetrahydrofolate compounds is described, comprising the conversion, for example, of only the 5,6S,7,8-tetrahydrofolic acid component of a racemic mixture of 5,6,7,8-tetrahydrofolic acid to 10-formyl-5,6S,7,8-tetrahydrofolic acid in the presence of a formyl tetrahydrofolate synthetase, followed by cyclizing, hydrolyzing and derivatizing. The process is also useful to make a desired substantially pure (6R or 6S) enantiomer of a derivative of (radiolabeled) tetrahydrofolic acid or a salt or ester thereof. |