PROCESS FOR THE PREPARATION OF PIPERAZINE DERIVATIVES

摘要

The invention relates to a process for the preparation of the trans N-{4-{2-[4-(2,3- dichlorophenyl)-piperazine-1-yl]-ethyl}-cyclohexyl}-carbamide derivatives of formula (I) by reacting the compound of formula (III) with a carbamoylchloride of formula (II) which comprises carrying out the reaction in a mixture of a solvent and concentrated aqueous solution of an alkali hydroxide at a temperature between 40-100 °C in the presence of a phase transfer catalyst, separating the phases and washing the organic layer then removing the solvent and drying the compound of formula (I) obtained until its weight is constant.