Synthesis and Cytotoxic Activity of Some Novel Thieno[2,3-d:4,5-d']Dipyrimidine Derivatives.

Synthesis of some novel tricyclic compounds bearing thienodipyrimidine moiety by the reaction of ethyl 6-amino-1,3-dimethyl-2,4-dioxo-1,2,3,4-tetrahydrothieno[3,2-d]pyrimidine-7-carboxylate (1) with different types of aromatic amines to give the corresponding carboxamide derivatives 2-11, which cyclized with triethyl orthoformate in acetic anhydride to afford thieno[2,3-d:4,5-d']dipyrimidine derivatives 12-15 is described. Similarly, thieno[2,3-d:4,5-d']dipyrimidine derivative 17 was also prepared via the reaction of carboxamide derivative 2 with chloroacetyl chloride in chloroform to give thieno[3,2-d]pyrimidine-7-carboxamide derivative 16, followed by a cyclization in boiling acetic anhydride. The structure of these compounds was confirmed on the basis of their spectral and analytical data such as IR, 1H-NMR, 13C-NMR spectroscopy and mass spectral data. The synthesized compounds were screened for their cytotoxic activity.