Abstract: The invention relates to a process for the preparation of onium salts having a low chloride content by reaction of an onium chloride with an acid, where the hydrochloric acid forming is removed by azeotropic distillation by coordination to an organic solvent which forms an azeotropic mixture with water.
Type:
Grant
Filed:
June 17, 2005
Date of Patent:
April 6, 2010
Assignee:
Merck Patent Gesellschaft mit beschrankter Haftung
Inventors:
Nikolai (Mykola) Ignatyev, Urs Welz-Biermann, Peter Barthen, Helge Willner
Abstract: Citalopram can be industrially and economically produced and at a high yield by reacting a compound of the following formula [VI] with 3-(dimethylamino)propyl chloride in the presence of at least one of N,N,N′,N′-tetramethylethylenediamine and 1,3-dimethyl-2-imidazolidinone and a condensing agent. The compound of the following formula [III], which is a key compound for the production of citalopram, can be easily produced by subjecting the compound of the following formula [II] to reduction and cyclization.