[EN] A PROCESS FOR THE SYNTHESIS OF LOFEXIDINE<br/>[FR] PROCÉDÉ DE SYNTHÈSE DE LOFEXIDINE
申请人:PROCOS SPA
公开号:WO2020254580A1
公开(公告)日:2020-12-24
Disclosed is a process for the synthesis of lofexidine of formula (I) and the hydrochloride salt thereof (II), from ethyl 2-(2,6-dichlorophenoxy)propionate (III) and ethylenediamine in the presence of tetravalent titanium alkoxides, preferably titanium isopropoxide, in an apolar solvent such as toluene. A further object of the present invention is a process for the preparation of the intermediate ethyl 2-(2,6-dichlorophenoxy)propionate (III) from 2,6-dichlorophenol and ethyl 2-chloropropionate in the presence of a polar aprotic solvent and an alkali or alkaline earth carbonate salt, preferably potassium carbonate. Both processes are more cost-effective and more easily industrially scalable than the known procedures, thus enabling the active ingredient to be obtained with high yields at a limited cost.
本发明揭示了一种合成Lofexidine的方法,该方法使用乙基2-(2,6-二氯苯氧基)丙酸酯(III)和乙二胺在四价钛烷氧化物的存在下(最好是异丙醇钛)在类似甲苯的无极性溶剂中合成Lofexidine的化学式(I)及其盐酸盐(II)。本发明的另一个目标是一种制备中间体乙基2-(2,6-二氯苯氧基)丙酸酯(III)的方法,该方法使用2,6-二氯苯酚和乙基2-氯丙酸酯在极性无水溶剂和碱性或碱土碳酸盐的存在下(最好是碳酸钾)进行反应。这两种方法比已知的程序更具成本效益,更容易实现工业化规模化,从而以较低的成本获得高产率的活性成分。