A series of 31 chalcone-and flavonoid-based derivatives were synthesized in good overall yields and screened for their inverse agonist activity on the US28 receptor of human cytomegalovirus (HCMV). With one exception (eg, 2-(5-bromo-2-methoxyphenyl)-3-hydroxy- 4 H-chromen-4-one), halogen-substituted flavonoids were typically more potent inverse agonists than their related hydro derivatives. While toxicity could be used to partially ...