Process for the preparation of 4-[2-(dimethylamino)-ethoxy]2-methyl-5-(1-methylethyl)-phenol esters and their salts

摘要

This invention relates to a process for the preparation of 4-[2-(dimethylamino)-ethoxy]-2-methyl-5-(1-methylethyl)-phenol esters (I) and their salts with organic and inorganic acids comprising the reaction of thymol with a salt of an 1-halo-dimethylaminoethane to obtain ethylamine-N,N-dimethyl-2-(thymyloxy) (II), the subsequent reaction of (II) with an acylating agent according to the Friedel and Kraft reaction to obtain 4-[2-(dimethylamino)-ethoxy]-2-methyl-5-(1-methylethyl)-1-acyl-benzene (III) and the oxidation of (III) to obtain the products (I) which, if desired, may be transformed in their salts with organic or inorganic acids. This process allows to obtain the products (I) in high quality and quantity without isolating any intermediate product.