METHOD OF SYNTHESIS OF 1-(PARA-CHLOROBENZHYDRYL)-4-(2-HYDROXYETHYL)-PIPERAZINE Russian patent published in 2003 - IPC

FIELD: organic chemistry, chemical technology, chemical-pharmaceutical industry. SUBSTANCE: invention relates to the improved method of synthesis of 1-(para-chloro- benzhydryl)-4-(2-hydroxyethyl)-piperazine. Method involves interaction of 1-(2-hydroxyethyl)-piperazine with para-chlorobenzhydryl chloride at heating in toluene or acetone in the mole ratio of reagents = 1 : (0.5-2), respectively, followed by isolation of the end substance by concentration of reaction solution at slight pressure decrease, treatment with diluted hydrochloric acid, twice extraction with benzene and intermediate aqueous layer alkalization, washing out with water and repeated concentrating under slight pressure decrease. Process can be carried out in the presence of triethylamine taken in the amount 1-2 moles per mole of 1-(hydroxyethyl)-piperazine. The end substance is an intermediate compound used in synthesis of medicinal agent cetirizine. Method provides high quality of end product without distillation in the content of basic substance 100% and yield 84-87.7%. EFFECT: improved method of synthesis. 2 cl