Synthesis and biological evaluation of triazole based uracil derivatives as novel DPP-4 inhibitors

A series of triazole based uracil derivatives were designed and synthesized as novel DPP-4 inhibitors. Compound A01 was identified as a lead compound for SAR studies focused on the structural modification at the S_2' subsite of DPP-4. The novel analogues A02-A25 were obtained by modifying the substituents at the phenyl group, and B01-B09, by introducing the carbonyl group. On screening in DPP-4, compounds B03, B04 and B08 showed a significant improvement in DPP-4 inhibitory activities compared to compound A01 and showed comparable activities to the marketed DPP-4 inhibitor, alogliptin. Docking studies revealed new favorable binding modes of designed compounds in the S_2' subsite and proved that structural modifications in the S_2' subsite were an effective option to increase the inhibition of DPP-4. In vitro DPP-8 and DPP-9 tests indicated that all compounds showed excellent selectivity against DPP-8 and DPP-9. Further in vivo evaluation showed that compound B04 could significantly improve oral glucose tolerance in ICR mice and dose-dependently reduced glucose levels in type 2 diabetic C57BL/6 mice. These data suggest that compound B04 could be a promising DPP-4 inhibitor for future treatment of T2DM.