A series of thiouracil derivatives were designed, synthesized and screened for in vitro inhibition of dipeptidyl peptidase IV. The SAR study indicated the influence of substituted chemical modifications on thiouracil scaffold. Compounds 8 (IC50= 0.32 lM), 9 (IC50= 0.29 lM), and 12 (IC50= 0.25 lM) showed excellent dipeptidyl peptidase IV inhibition having heterocyclic substituted piperazine with acetamide linker resulted as most potent ...