Synthesis, in vitro evaluation of thymidine phosphorylase inhibitory activity, and in silico study of 1,3,5-triazin-2,4-dione and its fused analogues

Based on structural similarities with the reference compounds, a series of 1,3,5-triazin-2,4-dione and their fused analogues was designed, synthesized and their in vitro thymidine phosphorylase inhibitory potential was evaluated. The monocyclic analogues were found to be inactive. Among the different fused derivatives synthesized, compounds having keto group (C=O) at C7/C4 and thioketo group (C=S) at C5/C2 position showed TP inhibitory activity comparable to positive control, 7-deazaxanthine (7-DX) (IC50 value = 42.63 ?M). Molecular docking of the target compounds into the enzyme thymidine phosphorylase was performed to illustrate the important structural information on the plausible ligand-enzyme-binding interactions.