Synthesis, stability and activity of the prodrugs of dihydroorotate dehydrogenase inhibitors

This study was conductcd to improve structural instability of a highly active DHODH inhibitor A found in our group. Twelve prodrugs were synthesized by modifying the carboxyl group. The enzyme activity test of 12 prodrugs A1-A12 demonstrated that A1-A5 displayed weak inhibitory activity, and A6-A12 displayed no activity, which met the action mechanism of designed prodrug. The structural stability of A1-A12 in methanol and pH 2.0, 9.0 buffers were tested, and the results showed that A12 could avoid intramolecular ring-formation in CH3OH, A1-A8 were easily hydrolyzed under acidic conditions, and A9-A12 were inclined to hydrolyze under alkaline conditions. The cell proliferation inhibitory activity of 12 prodrugs were evaluated, in which compound A12 displayed excellent activity (IC50=0.63 pmol-L-1) similar to brcquinar. These results laid a good foundation for conducting further vivo studies.