Design, Synthesis and Anti-Proliferative Activities of 2,6-Substituted Thieno[3,2-d]pyrimidine Derivatives Containing Electrophilic Warheads.

Thieno[3,2-d]pyrimidine as an effective pharmacophore has been extensively studied. However, its 2,6-substituted derivatives are rarely reported. In the present study, eighteen 2,6-substituted thieno[3,2-d]pyrimidine derivatives containing electrophilic warheads were designed based on the first known Fibroblast growth factor receptor-4 (FGFR4) inhibitor Blu9931. Unexpectedly, all of the derivatives exhibited negligible activity against FGFR4. However, most of the target compounds exhibited antiproliferative activities against four human cancer cell lines, including A431, NCI-H1975, Ramos and SNU-16. Compound 12 showed the most potent antiproliferative activities on the above four cell lines with IC50 values of 1.4 μM, 1.2 μM, 0.6 μM, and 2.6 μM, respectively. Additionally, the antiproliferative activity of 12 against MDA-MB-221 proved that 12 had the selectivity towards certain tumor cell lines. Furthermore, preliminary structure-activity relationship analysis was discussed based on the experimental data.