Synthesis, analgesic, anti-inflammatory and ulcerogenic index activities of novel 2-methylthio-3-substituted-5,6-dimethyl thieno [2,3-d] pyrimidin-4(3H)-ones

A variety of novel 2-methylthio-3-substituted amino-5,6-dimethyl thieno [2,3-d] pyrimiclin-4(3H) -ones were synthesized by reacting 3-amino-2-methylthio-5,6-dimethyl thieno [2,3-d] pyrimidin-4(3H)-one with different aldehydes and ketones. The starting material 3-amino-2-methylthio-5,6-dimethyl thieno 12,3-d pyrimidin-4(3H)-one was synthesized from 2-amino-3-carbethoxy-4,5-dimethyl thiophene. The compounds were investigated for their analgesic activity in albino mice, and for their antiinflammatory and ulcerogenic index activities in Wistar rats. The compound 2-(1-ethylpropylideneamino)2-methylthio-5,6-dimethyl thieno [2,3-d] pyrimidin-4(3H)-one (AS2) showed the most potent analgesic activity of the series. It also showed more potent anti-inflammatory activity when compared to the reference standard, diclofenac sodium. The test compounds showed only mild ulcerogenic potential when compared to aspirin.