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.
本发明涉及一种改进的工艺,用于制备公式I中的3-[(2R,3R)-1-(
二甲氨基)-2-甲基戊-3-基]
苯酚和其药学上可接受的盐,其中包括将公式VIII中的(S)-1-(
二甲氨基)-2-甲基戊-3-酮与公式II中的3-
溴苯甲醚在
格氏试剂条件下反应,得到公式V的化合物(2S,3R)-1-(
二甲氨基)-3-(3-
甲氧基苯基)-2-甲基戊-3-醇,随后激活公式V的—OH基团,转化为公式IX的
磺酸酯,经还原脱氧得到公式VII的(2R,3R)-3-(3-
甲氧基苯基)-N,N,2-三甲基戊-1-胺,再对公式VII进行去甲基化反应,得到化合物3-[(2R,3R)-1-(
二甲氨基)-2-甲基戊-3-基]
苯酚,其为公式I。