Cambrex Charles City, Inc.

Greg S Buenger

Paul Alan Jass

Erik T Michalson

Jason Scott Douglas

Matthew Wendell Schiesher

Kezia Peixoto Schutz

The present invention relates to a process for the preparation of piperidine derivatives including sufentanil, and their pharmaceutically acceptable salts, such as the citrate salt in which a quaternary ammonium (nosylate) salt of an appropriate piperidine is reacted with a corresponding 4-NOsulfonate ester to produce the desired piperidine derivative at a high purity.

Method of making piperidine derivatives

A method in which a crude chlorinated product of a phenylpropanolamine, preferably prepared by reacting thionyl chloride with the phenylpropanolamine, is purified by contacting an aqueous solution of the crude product with carbon. The carbon-treated solution of the crude chlorinated product of a phenylpropanolamine is catalytically hydrogenated to the corresponding amphetamine derivative.

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Charles City, IA, United States of America

Greg S Buenger