Thieno[2,3‐d]pyrimidines in the Synthesis of Antitumor and Antioxidant Agents

Dimethyl acetylenedicarboxylate, ethyl propiolate, and E-dibenzoylethylene react with thienopyrimidines (cyclo-pentyl, -hexyl, and -heptyl) derivatives to form thiazolo[3,2-a]thieno-[2,3-d]pyrimidin-2-ylidene) acetates, thieno[2,3-d]pyrimidin-2-ylthioacrylates, and thieno[2',3':4,5]pyrimido[2,1-b][1,3]thiazin-6-ones, respectively. Reactions proceed via cyclization and thio-addition processes. Some derivatives of thienopyrimidines showed high inhibition of Hep-G2 cell growth compared with the growth of untreated control cells. However, the fused heptyl of thienopyrimidothiazines indicates a promising specific antitumor agent against Hep-G2 cells with IC(50 )< 20 microM.