Application of solid-phase chemistry for the synthesis of 3'-fluoro-3'-deoxythymidine

Reported solution-phase methods for the synthesis of 3'-fluoro-3'-deoxythymidine (FLT) are cumbersome, require purification of intermediates, and include several protecting/deprotecting steps. To circumvent these problems, a solid-phase strategy was designed for the synthesis of FLT. Thymidine was immobilized on trityl resin via the 5'-hydroxyl group. The subsequent mesylation of the free 3'-hydroxyl group in the presence of methanesulfonyl chloride afforded the polymer-bound 3'-O-mesylthymidine. Nucleophilic substitution of the mesyl moiety by hydroxyl group in the presence of sodium hydroxide produced the polymer-bound threothymidine. Fluorination with diethylaminosulfur trifluoride followed by acidic cleavage of the polymer-bound FLT in the presence of trifluoroacetic acid afforded FLT.