ENANTOSELECTIVE PREPARATION OF THE S-ENANTIOMER OF OMEPRAZOLE OR A MIXTURE OF S. AND R- ENANTIOMERS OF OMEPRAZOLE IN WHICH S-ENANTIOMER OF OMEPRAZOLE IS ENRICHED

摘要

The invention relates to a process for preparing the S-enantiomer of omeprazole or a mixture of S- and R- enantiomers of omeprazole, a mixture of the S- and R-enantiomers of omeprazole in which the omeprazole S-enantiomer is enriched. In the new process a prochiral sulphide is oxidized in an organic solvent with an oxidizing agent in the presence of a titanium(IV) complex, which can be obtained by reacting a titanium(IV) compound with a chiral, bidentate (R,R)- or (S,S)-1,2-bis-arylethane-1,2-diol, wherein the oxidation is carried out at a temperature about -20 to 25°C over a period of 10-20 min, and wherein catalytic oxidation is carried out free base.