NITROBENZOXADIAZOLE-LABELED POLYISOPRENOID ALCOHOLS

We have prepared, isolated, and characterized a series of nitrobenzoxa diazole labelled polyisoprenoid alcohols. The coupling reaction employ ed was a dicyclohexylcarbodiimide mediated condensation between a carb oxylic acid derivative of nitrobenzoxadiazole and the polyisoprenoid a lcohols citronellol, solanesol, and dolichol. Upon exposure to visible light, a self-sensitized singlet oxygen ''ene'' reaction oxidized dou ble bonds in the isoprene moiety. The rate of oxidation is greatly red uced in solvents where singlet oxygen is short-lived.