Abstract: This invention relates to a process for the preparation of antiinflammatory thieno [2,3-c]- and [3,2-c]pyridines having respectively the following formulae: ##STR1## in which R.sub.1 and R.sub.2, which may be the same or different, represent each a hydrogen atom or an alkyl group, and their pharmaceutically acceptable acid addition salts, comprising:(a) condensing a compound of the following formulae (VII) or (VIII), respectively, ##STR2## with a sulfonyl chloride having the formula ClSO.sub.2 R.sub.3, in which R.sub.3 is a lower alkyl radical or a phenyl radical optionally substituted with a halogen atom or a lower alkyl group, within a two-phase solvent system and in the presence of sodium carbonate;(b) oxidizing in a solvent medium the resulting alcohols having respectively the following formula (V) or (VI): ##STR3## (c) treating the resulting ketones, having the following formula (III) or (IV): ##STR4## with a basic agent having the formula RO.sup.- M.sup.