D-toreo - (R and R) - method of unnecessary enanchiomarisaikuru due to manufacturing and epimerizeshiyon of mechiruhuenideto

摘要

The present invention pertains to a process for obtaining a single enantiomer, d or l, of threo-methylphenidate, comprising resolution of a mixture of the enantiomers; racemisation of the unwanted enantiomer, to give a mixture of all four stereoisomers; and separation of the erythro stereoisomers, to leave the same mixture of enantiomers for resolution.