A novel, improved, and enantiospecific process for the preparation of (-)-trans-4-(4-fluorophenyl)-3-hydroxymethyl-1-methylpiperidine of formula-(I), an advanced intermediate in the manufacture of antidepressant drug paroxetine is disclosed in the present invention. Compound of formula-(XXII) is prepared by resolution of compound of formula-(XX) using a chiral acid followed by hydrogenation of the resolved amine. Michael addition of the compound of formula-(XXII) onto acrylate esters gave the compounds of formula-(XXIII). Conversion of the hydroxy group present in compound of formula-(XXIII) into a leaving group followed by treatment with a strong base gave the enantiospecific intramolecularly cyclized piperidine derivative of formula-(XXV). Reduction of the ester group present in compound of formula-(XXV) with a metal hydride reducing agent gave the compound of formula-I with more than 97% chiral purity. Further purification of compound of formula-I to >99.5% is achieved by one recrystallization from a number of solvents. Present process is easily adaptable for commercial preparation of (-)-trans-4-(4-fluorophenyl)-3-hydroxymethyl-1-methylpiperidine of formula-(I).
                            本发明揭示了一种用于制备抗抑郁药
帕罗西汀的先进中间体(-)-
反式-4-(4-氟苯基)-3-羟甲基-1-甲基哌啶的改进和对映具体过程。通过使用手性酸对化合物XX进行拆分,然后对已拆分的胺进行氢化,制备了化合物XXII的方法。将化合物XXII与
丙烯酸酯发生迈克尔加成反应,得到了化合物XXIII。将化合物XXIII中的羟基转化为一个脱离基,然后经过强碱处理,得到了对映具体的分子内环化
哌啶衍
生物XXV。将化合物XXV中的酯基还原为
金属
氢化物还原剂,得到了具有超过97%对映纯度的化合物I。通过在多种溶剂中进行一次结晶,将化合物I进一步纯化至>99.5%。本过程易于用于商业制备(-)-
反式-4-(4-氟苯基)-3-羟甲基-1-甲基哌啶的方法。