Disclosed herein is an improved process for the preparation of 3-[(2R,3R)-1-(dimethylamino)-2-methylpentan-3-yl]phenol of Formula-I and its pharmaceutically acceptable salt which comprises the reaction of (S)-1-(dimethylamino)-2-methylpentan-3-one of formula VIII with 3-bromo anisole of formula II under Grignard conditions to get the compound (2S, 3R)-1-(dimethylamino)-3-(3-methoxyphenyl)-2-methyl pentan-3-ol of formula V followed by activation of the —OH group of the formula V to convert into sulfonate esters of formula IX, which are on reductive deoxygenation to yield (2R,3R)-3-(3-methoxyphenyl)-N,N,2-trimethylpentan-1-amine of formula VII and demethylation of formula VII to obtain the compound 3-[(2R,3R)-1-(dimethylamino)-2-methylpentan-3-yl]phenol of Formula-1.
本文揭示了一种改进的制备3-[(2R,3R)-1-(二甲基
氨基)-2-甲基戊基]
苯酚(
化学式I)及其药用可接受盐的方法,包括将
化学式VIII的(S)-1-(二甲基
氨基)-2-甲基戊酮与
化学式II的3-
溴苯甲醚在
格氏试剂条件下反应,得到化合物(2S, 3R)-1-(二甲基
氨基)-3-(3-
甲氧基苯基)-2-甲基
戊醇(
化学式V),随后激活化合物V的—OH基团,转化为
磺酸酯(
化学式IX),再经还原脱氧作用得到(2R,3R)-3-(3-
甲氧基苯基)-N,N,2-三甲基戊酰胺(
化学式VII),对
化学式VII进行去甲基化反应,得到化合物3-[(2R,3R)-1-(二甲基
氨基)-2-甲基戊基]
苯酚(
化学式I)。