5-Iodo-2'-deoxyuridine (I) is protected at the primary hydroxyl group with 4,4'-dimethoxytrityl chloride to afford the 5'-O-trityl derivative (II). Subsequent esterification of the remaining hydroxyl group of (II) with succinic anhydride (III) yields the succinate mono-ester (IV). Acid (IV) is then coupled with diethylene glycol in the presence of DCC to produce (V). The O-trityl group of (V) is finally removed by treatment with formic acid, to give the title compound.
5-Iodo-2'-deoxyuridine (I) is protected at the primary hydroxyl group with 4,4'-dimethoxytrityl chloride to afford the 5'-O-trityl derivative (II). Subsequent esterification of the remaining hydroxyl group of (II) with succinic anhydride (III) yields the succinate mono-ester (IV). Acid (IV) is then coupled with triethylene glycol in the presence of DCC to produce (V). The O-trityl group of (V) is finally removed by treatment with formic acid, to give the title compound.