| 摘要 |
A novel process for the preparation of omeprazole and its enantiomers, su ch as esomeprazole, as well as the preparation of related 2-(2-pyridinylmeth yl-sulphinyl)-1H-benzimidazoles, including pantoprazole, lansoprazole and ra beprazole, as recemates or single enantiomers, and their alkali or alkaline salts has been developed. The novel process involves the surprising discover y that protection of the free-base benzimidazole sulfoxide (e.g. omeprazole or esomeprazole), by reaction with an alkyl, aryl or aralkyl chloroformate f ollowing oxidation of the corresponding sulfide, eliminates the need for its direct isolation. Subsequent removal of the protecting group with a solutio n of alkali or alkaline earth alkoxide in a C1-C4 alcohol directly provides the corresponding salt. By eliminating the need to handle the free-base benz imidazole sulfoxide, this advantageous procedure provides increased chemical yields over processes described in the art.
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