The cyclizing reaction of cinnamic acid (Ia) with thionyl chloride was optimized and a series of 3-chloro-6-subst.benzo[b]thiophene-2-carbonyl chlorides Va-Vn was prepared. Chloride Va was transformed into a series of N-aryl-3-subst. (Cl, OCH3, OH) benzo[b]thiophene-2-carboxamides VII, IX, X. The drugs were subjected to an evaluation of selected antileucotriene activites in vitro and of the anti-inflammatory effect in vivo. In agreement with the assumed mechanism, inhibition of the ear inflammation is conditioned by the antileucotriene activity, whereas inhibition of the carrageen oedema is not due to this mechanism alone.

        Key words: subst.benzo[b]thiophene-2-carboxamides – synthesis – antiinflammatory effect – antileucotriene activity