A chemical method for the separation of letrozole precursor 4-[1-1,2,4-triazolyl)methyl]benzonitrile of formula (I) from the isomeric unwanted byproduct 4-[1-(1,3,4-triazolyl)methyl]benzonitrile of formula (II) of the reaction in which it is produced, which comprises (a) Preparing an isomeric mixtures of the compounds of formula (I) and (II) by conventional methods. (b) Dissolving the resultant crude isomeric mixture in dichloro methane (or) chloroform. (c) Adding 10-14% isopropylalcohol hydrochloride (IPACHI) to the resulting solution. (d) Adding isopropyl ether to precipitate undesired isomer is hydrochloride form. (e) Filtering off the undesired isomer hydrochloride. (f) Distilling off the filtrate completely. (g) Adding dilute sodium hydroxide solution and dichloromethane to the residue to liberate required isomer base of the formula (I). (h) Evaporating the separated dichloromethane layer and charging hexane or petroleum ether. (i) Centrifuging the resultant product of the formula (I) and washing with hexane or petroleum ether.
一种用于分离
来曲唑前体4-[1-(
1,2,4-三唑基)甲基]苯腈(公式I)的反应中产生的同分异构体副产物4-[1-(1,3,4-三唑基)甲基]苯腈(公式II)的
化学方法,包括以下步骤:(a) 通过常规方法制备公式(I)和(II)的化合物的同分异构体混合物。(b) 将得到的粗同分异构体混合物溶解在
二氯甲烷(或)
氯仿中。(c) 向所得溶液中加入10-14%
异丙醇盐酸盐(
IPACHI)。(d) 加入
异丙醚以沉淀不希望的异构体,以
盐酸形式存在。(e) 过滤掉不需要的异构体
盐酸。(f) 将滤液完全蒸馏掉。(g) 向残留物中加入稀释的
氢氧化钠溶液和
二氯甲烷,以释放所需的公式(I)的异构体碱基。(h) 蒸发分离的
二氯甲烷层,并加入己烷或石油醚。(i) 对得到的公式(I)的产品进行离心,并使用己烷或石油醚进行洗涤。