Tetrabutylammonium Fluoride → 2',3'-Dideoxythymidine

A 1M solution of tetra-butylammonium fluoride in THF (0.35 mL, 0.35 mmol), was added to a solution of 5'-O-(t-butyldiphenylsilyl)-3'-deoxythymidine (0.162 g, 0.35 mmol) in THF (3 mL). The reaction mixture was stirred at room temperature for 3 hours, at which time thin layer chromatography indicated complete disappearance of the starting material. The solvent was removed under reduced pressure. The residue was dissolved in a minimum volume of chloroform and then purified by passing it through a vacuum column packed with silica gel. The column was eluted with methanol, followed by 6% methanol in chloroform. Compound 11 was obtained from the final eluent as a white crystalline solid. The product obtained was twice crystallized from ethyl acetate. Yield 0.063 g, 80%. 1H NMR (DMSO- d6, 90 MHz): δ 1.77 (s, 3 H, 5-CH3); 1.7-2.3 (m, 4 H, 2' and 3' H); 3.60 (m, 2 H, 5'-H); 4.00 (m, 1 H, 4'-H); 5.01 (t, 1 H, 5'-OH, J=5.4 Hz, D2O exchangeable); 5.95 (dd, 1 H, 1'-H, J=5.5 and 6.5 Hz); 7.79 (s, 1 H, 6-H); 11.20 (br s, 1 H, NH, D2O exchangeable); mp 151°-152° C.; [α]D +18.3(c=0.999, MeOH).