Synthesis and pharmacological properties of thieno[2',3':4,5]pyrimido [2,1-b][1,3,4]thiadiazine derivatives.

A new series of 2-substituted-7,8-dimethyl-3H,9H-thieno[2',3':4,5]pyrimido[2,1-b][1,3,4]thiadiazin-9-ones 5a-d and 6a,b was synthesized through the hydrazinium (1+) salt of 3-amino-2,3-dihydro-5,6-dimethyl-2-thioxo-thieno[2,3-d]pyrimidin-4(1H)-one, 2. These derivatives and two analogs 10a,b were tested for their analgesic and antiinflammatory properties. The pharmacological results are discussed in comparison with those of related compounds previously tested