Kagan-Modena-procedure

An application of the Kagan-Modena procedure for the synthesis of the enantio-merically pure S enantiomer of omeprazol was reported by Cotton et ol. [69] This enantiomer is called esomeprazol and is the active component of Nexium . It is a highly potent gastric acid secretion inhibitor. 

The Kagan reagent was used at Eli Lilly to resolve racemic thiazolidinone (60) (Scheme 1.16) [153]. At 60% and 80% completion, the ee s of recovered (-)-(60) were 67% and 94%, respectively. The Modena procedure (i.e. no added water in the reagent system) gave a much slower reaction, but the ee shows only a small decrease. 

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