Patent ID: 7229557
Filing Date: 2007-06-12
Classification: A61K,C07D

Abstract:
1. A method to isolate d-threo-methylphenidate in greater than 99 percent enantiomeric excess from a racemic mixture of d-threo-methylphenidate and l-threo-methylphenidate, comprising the steps of: providing a racemic mixture comprising d-threo-methylphenidate and l-threo-methylphenidate; treating said racemic mixture with dibenzoyl-L-tartrate to obtain a second mixture of d-threo-methylphenidate and l-threo-methylphenidate from said racemic mixture, wherein said second mixture comprises d-threo-methylphenidate having greater than a 90 percent enantiomeric excess; supplying l-fenchyloxyacetic acid; treating said second mixture with said l-fenchyloxyacetic acid; collecting d-threo-methylphenidate having greater than a 99 percent enantiomeric excess.