Pyridine → Benzyloxymethyl-3'-O-(phenoxythiocarbonyl)-5'-O-tert-butyldiphenylsilylthymidine

Participants

Reaction Conditions

Reaction Steps

N-hydroxysuccinimide (3.9 g, 34 mmol) and pyridine (24.3 mL, 300 mmol) were added to a solution of the alcohol 3 (90.0 g, 150 mmol) in 1 L of toluene. The mixture was warmed up to 80° C. and stirred for 10 min. Phenyl chlorothionoformate (30 g, 174 mmol) was added to the solution and the resultant reaction mixture was stirred at 80° C. for 8 h. The hot toluene solution was decanted from solids. The solids were rinsed with AcOEt (2×30 mL) and the combined toluene solution and AcOEt washes were concentrated under reduced pressure. The residue was purified by silica gel column chromatography (hexanes/AcOEt 9:1 then 3:1) to give 83.0 g (75.2%) of the title compound, 17, as a light yellow foam. Rf (hexanes/AcOEt 9:1) 0.24. 13C-NMR (CDCl3): 12.97 (5-CH3), 19.49 (2'-C), 27.16 (Me3C), 38.32 (Me3C), 64.87 (O--C-Ph), 70.75 (N--C--O), 72.28 (5'-C), 84.21 (4'-C), 84.90 (3'-C), 85.39 (1'-C), 110.82 (5-C), 121.95, 126.94, 127.72, 128.27, 128.40, 129.81 (Ar--C), 130.35 (6-C), 131.93, 132.79, 133.76, 135.38, 135.76, 138.30 (Ar--C), 151.05 (2-C), 153.42 (Ar--C), 163.40 (4-C), 194.36 (thioformate-C).

Provenance & Evidence