Polystyrene beads bound α-diketones, 4-(1,2-dioxo-2-phenylethyl)polystyren and 4-(1,2-dioxopropyl) polystyrene were synthesized. Photolysis of oxygen saturated solution of 1,3-dimethylthymine in the presence of the insoluble polymer bound α-diketone and subsequent treatment of the unstable intermediate with nucleophiles produced sterco- and regio-specific 5-hydroxy-6-substituted dihydro-1,3-dimethylthymine derivatives. High recovery of polymer-bound benzil after photooxygenation showed it was significantly more stable toward bleaching than the free α-diketones and could be reused at least five times.
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