ABSTRACT
This study was conducted 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 μmol·L−1) similar to brequinar. These results laid a good foundation for conducting further vivo studies.
ABSTRACT
In this study, 1-(3-(4-chlorophenyl)-5-methylthio-1H-1,2,4-triazol-1-yl)-butan-1-one discovered previously in our lab was selected as a inhibitor of human dihydroorotate dehydrogenase (HsDHODH) for structural optimization. The co-crystal of HsDHODH with the hit was obtained and analyzed for guiding the subsequent structural optimization. As a result, a series of novel triazole derivatives were designed and synthesized as potent HsDHODH inhibitors. Among them, compound (3-(4-chlorophenyl)-5-ethylthio-1H-1,2,4-triazol-1-yl)-furan-2-yl-methanone displayed high potency in the inhibition of HsDHODH with an IC50 value of 1.50 μmol·L-1. Meanwhile, the structure-activity relationships were analyzed based on the biological data and the co-crystal structure. These results provide a valuable reference for optimization of 1H-1,2,4-triazole derivatives as HsDHODH inhibitors in the future.