Reaction #4982

Reaction equation

2', 3'-dideoxycytidine

Iodine

→

iodide

Yield 83.0%

5-iodo-2', 3'-dideoxycytidine

Yield 83.0%

Solvents

methanol

methanol

dichloromethane

Conditions

Workup

1. 1
   workup.ADDITIONthe free base form of AG3 X4A resin (20 mL, 38 meq, Bio-Rad) was added
2. 2
   Otherhydrogen sulfide was bubbled into the reaction for 15 minutes
3. 3
   OtherComplete precipitation of mercury(II)
4. 4
   FiltrationThe reaction was filtered
5. 5
   Filtrationthrough filter aid
6. 6
   Washthe filter aid was washed with 1:1 methanol-dichloromethane
7. 7
   OtherThe filtrate was evaporated onto silica gel (10 g)
8. 8
   WashElution

Procedure

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 hours. 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°. After 4 hours, the free base form of AG3 X4A resin (20 mL, 38 meq, Bio-Rad) was added and hydrogen sulfide was bubbled into the reaction for 15 minutes. Complete precipitation of mercury(II) was verified by TLC. The reaction was filtered through 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 siliva gel was placed on top of a 150 g silica gel column. Elution was 5%, 10%, and 20% methanol in dichloromethane afforded 2.79 g (83%) of iodide 19 as a colorless crystalline solid. Two recrystallizations form boiling water afforded, after vacuum-drying at 50°, large, analytically-pure prisms (mp: d 178° ).

Source