Synthesis of [60]fullerene–glycopyranosylaminopyrimidin-4-one conjugates

The synthesis of several C60 derivatives containing a 6-(β-d-glycopyranosylamino)pyrimidin-4-one unit and a C60–uridine conjugate is described. The fullerene derivatives bearing a 4-(β-d-glycopyranosylamino)pyrimidin-4-one moiety were synthesised by 1,3-dipolar cycloaddition reactions of C60 with azomethine ylides generated in situ from the corresponding 5-formylpyrimidin-4-one derivatives and N-methylglycine. The synthesis of the C60–uridine conjugate involved the selective protection of the 2′- and 3′-hydroxyl groups of uridine, esterification, cyclopropanation of C60 and, finally, the deprotection of the hydroxyl groups. One of the fullerene–glycopyranosylaminopyrimidin-4-one conjugates was characterised by single-crystal X-ray crystallography. Differentiation between pairs of diastereoisomers, for several fullerene derivatives, was achieved through the study of their gas-phase fragmentations.