Patent ID: 7176319
Filing Date: 2007-02-13
Classification: C07D

Abstract:
1. A process for preparation of sulfoxide of formula I(i) as enantiomers or enantiomerically enriched enantiomers or a salt thereof: which process comprises: a) reacting a mixture of enantiomers of 5-Methoxy-2-[(3,5-dimethyl-4-methoxy-2-pyridyl) methylsulfinyl]1-H-benzimidazole or a salt thereof with (S)— or (R) camphor sulfonylchloride to obtain diastereomeric mixture of 1-(S)-camphor sulfonyl-5-methoxy-2-[(3,5-dimethyl-4-methoxy-2-pyridyl)methyl-(R/S)-sulfinyl]-1H-benzimidazole and 1-(S)-camphor sulfonyl-6-methoxy-2-[(3,5-dimethyl-4-methoxy-2-pyridyl)methyl-(R/S)-sulfinyl]-1H-benzimidazole, b) separating the diastereomers formed in step (a); and c) deprotecting the separated diastereomers with an acid or base to provide a single enantiomer or enantiomerically enriched compound of (R)- or (S)-5-Methoxy-2-[(3,5-dimethyl-4-methoxy-2-pyridyl)methylsulfinyl]1-H-benzimidazole ((R)- or (S)-esomeprazole) and optionally preparing the (R)- or (S)-esomeprazole as the salt.