Applications of triphenylpyrylium salt-sensitized electron-transfer photo-oxygenation reactions to the synthesis of benzo-fused 1,4-diaryl-2,3-dioxabicyclo[2.2.2]octanes as new antimalarial cyclic peroxides

Abstract

Benzo-fused 1,4-diaryl-2,3-dioxabicyclo[2.2.2]octanes 4a–d (4a: Ar = C6H5, 4b: Ar = p-FC6H4, 4c: Ar = p-MeC6H4, 4d: Ar = p-MeOC6H4) were synthesized by 2,4,6-triphenylpyrylium tetrafluoroborate (TPPBF4)-sensitized photoinduced electron-transfer (PET)-promoted oxygenation reactions, and their in-vitro antimalarial activity was evaluated. The results showed that these substances have sufficiently high activity to enable them to serve as antimalarial lead compounds. In addition, TPPBF4-biphenyl-cosensitized PET oxygenation was shown to be an efficient method for introduction of an O–O moiety in the construction of antimalarial cyclic peroxides. New antimalarial bicyclic peroxides 4 were synthesized by TPPBF4-sensitized photoinduced electron-transfer oxygenation reactions.