4,5-Dihydroxypyrimidine Methyl Carboxylates, Carboxylic Acids, and Carboxamides as Inhibitors of Human Cytomegalovirus pUL89 Endonuclease.

Human cytomegalovirus (HCMV) terminase complex entails a metal-dependent endonuclease at the C-terminus of pUL89 (pUL89-C). We report herein the design, synthesis, and characterization of dihydroxypyrimidine (DHP) acid ( 14 ), methyl ester ( 13 ), and amide ( 15 ) subtypes as inhibitors of HCMV pUL89-C. All analogs synthesized were tested in an endonuclease assay and a thermal shift assay (TSA) and subjected to molecular docking to predict binding affinity. Although analogs inhibiting pUL89-C in the sub-μM range were identified from all three subtypes, acids ( 14 ) showed better overall potency, substantially larger thermal shift, and considerably better docking scores than esters ( 13 ) and amides ( 15 ). In the cell-based antiviral assay, six analogs inhibited HCMV with moderate activities (EC 50 = 14.4-22.8 μM). The acid subtype ( 14 ) showed good in vitro ADME properties, except for poor permeability. Overall, our data support the DHP acid subtype ( 14 ) as a valuable scaffold for developing antivirals targeting HCMV pUL89-C.