Merck + Co., Inc.

Arthur J Zambito

Edward J Grabowski

Robert F Czaja

John Budavari

William F Shukis

Paul Davis

Crystalline salts of (R,S)-pivaloyloxyethyl esters of (S)-3-(3,4-dihydroxyphenyl)-2-methylalanine, processes for their preparation and pharmaceutical composition are disclosed.

Crystalline salts of L or (S)-3-(3,4-dihydroxyphenyl)-2-methylalanine

This invention relates to the process for the purification of 3,6-bis(5-chloro-2-piperidinyl)-2,5-piperazinedione dihydrochloride, also known as Compound 593A, obtained as the free base from the fermentation broth of a strain of Streptomyces griseoluteus designated as NRRL 3412 by adsorbtion of the compound on a resin comprising a nonionic macro porous copolymer of styrene cross-linked with divinylbenzene. The resin is eluted with an organic aqueous dilute mineral acid solvent mixture in which the adsorbed compound is soluble. The compound is extracted from the eluate and further purified by fractional crystallization.

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Clark, NJ, United States of America

Arthur J Zambito