PROCESS FOR THE PREPARATION OF 1,3,4-TRIMETHYL-2-(3,4,5-TRIMETHOXYBENZYL)-1,2,5,6-TETRAHYDROPYRIDINE

摘要

A process for the preparation of 1,3,4-trimethyl-2-(3,4,5-trimethoxybenzyl) 1,2,5,6-tetrahydropyridine of formula (I) and its addition salts with pharmaceutically acceptable acids, for example halohydrides, which comprises in a first stage reacting 3,4,5-trimethoxybenzaldehyde of formula with 2-bromo-3,4-dimethylpyridine of formula the said reaction being effected in an inert solvent in the presence of butyl-lithium at a reaction temperature between-40.degree.C and ambient temperature, to form as an intermediate product 3,4,5-trimethoxyphenyl-(3,4-dimethyl-2-pyridyl) carbinol of formula (II) which in a second stage is reacted at a temperature below 20.degree.C with thionyl chloride, the chloride thus obtained is dissolved in glacial acetic acid and reduced with powdered zinc to form a product which is treated with methyl iodide to produce 1,3,4-trimethyl-2-(3,4,5-trimethoxybenzyl)-pyridine iodide, which is treated with sodium borohydride to produce the compound of formula I which, if desire, is converted into an acid addition salts thereof with a pharmaceutically acceptable acid, for example a halohydride.