Mechanism-based design, synthesis and biological studies of N⁵-substituted tetrahydrofolate analogs as inhibitors of cobalamin-dependent methionine synthase and potential anticancer agents.

A number of 8-deazatetrahydrofolates bearing electrophilic groups on N(5) were designed and synthesized based on the action mechanism of methionine synthase, and their biological activities were investigated as well. Compounds (11b, 12b and 16) showed the most active against methionine synthase (IC(50): 8.11 μM, 1.73 μM, 1.43 μM). In addition, the cytotoxicity to human tumor cell lines and dihydrofolate reductase (DHFR) inhibition by target compounds were evaluated.