Iodine → 2',3'-Dideoxy-5-iodocytidine

Beteiligte Stoffe

Reaktionsschritte

A solution of 2',3'-dideoxycytidine (2.11 g, 10 mmol, Raylo) and mercuric acetate (3.35 g, 10.5 mmol, Fisher) in 50 mL of methanol was refluxed for 19 h. The resulting white suspension was diluted with methanol (50 mL) and dichloromethane (100 mL). Iodine (3.05 g, 12 mmol) was added and the suspension was stirred at 25° until a clear purple solution was present. After 4 h, the free base form of AG3 X4A resin (20 mL, 38 meq, Bio-Rad; a weakly basic polystyrene resin) was added and hydrogen sulfide was bubbled into the reaction for 15 min. Complete precipitation of mercury(II) was verified by TLC. The reaction was filtered though filter aid and the filter aid was washed with 1:1 methanol-dichloromethane. The filtrate was evaporated onto silica gel 10 g) and the loaded silica gel was placed on top of a 150 g silica gel column. Elution with 5%, 10% and 20% methanol in dichloromethane afforded 2.79 g (83%) of iodide 44 as a colorless crystalline solid. Two recrystallizations from boiling water afforded, after vacuum-drying at 50°, large, analytically-pure prisms (mp: d 178°).

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