Synthesis of functionalized 5-(3-R-1-adamantyl)uracils and related compounds

Efficient synthetic approaches to functionalized 5-(3-R-1-adamantyl)uracils and related compounds (R=OH, COOH, NH₂, etc.) are described. The selective hydroxylation of the adamantane tertiary C-H bonds in 5-(1-adamantyl)uracils with H₂SO₄ in trifluoroacetic anhydride is used as the key step. Subsequent electrophilic reactions of 5-(3-hydroxy-1-adamantyl)uracils with N- and C-nucleophiles in CF₃COOH, H₂SO₄ or H₂SO₄/AcOH media yielded derivatives with amide, amino, aryl, carboxy and thiourea groups in the adamantane core. The preliminary evaluation of the antiviral activity revealed that some of the synthesized species display moderate antiviral activity against HSV-1 (SI∼20) in Vero cells.