PROCESS FOR THE PREPARATION OF (6S)- AND (6R)-TETRAHYDROFOLATES

摘要

The invention relates to a process for the preparation of (6S)- and (6R)-tetrahydrofolic acid and their addition salts with a sulfonic acid or with sulfuric acid, which is characterized in that (6R,S)tetrahydrofolic acid is reacted with a sulfonic acid or with sulfuric acid, resulting acid addition salt is fractionally crystallized and, if desired, the (6S)- or (6R)-tetrahydrofolic acid is liberated from the resulting diastereomeric acid addition salts by treatment with a base and isolated. The invention additionally relates to the novel acid addition salts of (6S)- and (6R)-tetrahydrofolic acid with a sulfonic acid or with sulfuric acid, their use as medicaments or starting material for the preparation of a medicament and their use for the preparation of optically active 5-methyl-, 5-formyl- and 5,10-methylene-tetrahydrofolic acids and their salts with strong bases and acids.