[A new nitrogen-containing polycyclic system. Synthesis and pharmacologic properties of benzofuran and thienothiadiazolepyrimidine derivatives. I].

A series of 5H-benzofuro[3,2-d]1,3,4-thiadiazolo[3,2-a]-pyrimidin-5-ones and 1,3,4-thiadiazolo[3,2-a]thieno[2,3-d]pyrimidin-5-ones were synthesized and their analgesic, antiinflammatory, antiexudative and ulcerogenic activities were evaluated. The analgesic and antiexudative activities of several derivatives proved to be less than that of indomethacin and much higher than that of mefenamic and acetylsalicylic acids. Acute toxicity and ulcerogenic effects were significantly lower than those of reference drugs.