Process for the preparation of new 2-(RS)-substituted 2,3- dihydro-5-oxy-4,6,7-trimethyl benzofurans and pharmaceutical compositions containing them

摘要

The invention relates to a process for preparing compounds of formula I <IMAGE> or their pharmaceutically acceptable salts, which comprises following a scheme of synthesis which uses a partly acetic 2-(RS)-2,3-dihydro-5-hydroxy-4,6,7- trimethyl benzofuran acid which comprises the following stages in corresponding order: a) alkylation of the hydroxyl radical at the 5 position using a known process, such as treatment with dialkyl sulphate in an alkaline solution or with an alkyl halide in solution in an organic solvent such as dimethyl formamide or again with triphenyl phosphine, dialkyl azodicarboxylate and a suitable alcohol in solution in an organic solvent such as tetrahydrofuran, b) reducing the compounds so obtained using a suitable reducing agent having a carboxylic group such as lithium aluminium hydride in solution in an ether solvent such as tetrahydrofuran.