Synthesis and pharmacological evaluation of thieno[2,3-d]pyrimidin-2,4-dione and 5H-pyrimido [5,4-b]indol-2,4-dione derivatives.

Two series of novel derivatives based on the thienopyrimidine and pyrimidoindole ring systems, both N-substituted in position 3, have been synthesized. The compounds were obtained by reaction of N-amino groups of 5,6-dimethyl-thieno[2,3-d]pyrimidin-2,4-dione and of 5H-pyrimido[5,4-b]indol-2,4-dione with aromatic aldehydes. Some of these substances showed an appreciable analgesic activity, a good antiinflammatory activity, a low acute toxicity with an optimal gastric tolerance.