Synthesis and Cytotoxicity of Some Thieno[2,3-d]pyrimidine Derivatives

A series of compounds 5-amino-2-ethylmercapto-4-phenyl-6-subistitutedthieno[2,3-d]pyrimidines (8a-d), 4-chloro-7-ethylmercapto-9-phenylpyrimido[5',4':4,5]thieno[3,2-d]triazine (9), and 2-ethyl-mercapto-8-oxo-4-phenyl-7-(4-chlorophenyl)pyrimido [4',5':4,5]thieno[2,3-d]pyrimidine (10) were synthesized and their structures were confirmed by H-1 NMR, C-13 NMR, and MS. All compounds were evaluated for their IC50 values against three cancer cell lines (MCF-7, HUH-7 and BHK) and WISH cells. The IC50 of compound (8d) was calculated for each cell line. Interestingly, the IC50 for the normal human amnion WISH cell line was much higher (723 pg/mL) than those found for the tumor cell lines BHK (17 mu g/mL), HUH-7 (5.8 mu g/mL), and MCF-7 (8.3 mu g/mL). The proliferation inhibition of normal (WISH) and tumor (BHK, HUH-7, and MCF-7) cells by compound (8d) was investigated using MTT assay, and the IC50 was calculated after 48 h of treatment for each cell line.