Reaction #3747

Reaction equation

5'-O-(4,4'-dimethoxytrityl)thymidine

imidazole

tert-butyl-dimethylsilyl chloride

→

5'-O-(4,4'-dimethoxytrityl)-3'-O-(tert-butyldimethlsilyl) thymidine

Solvents

DMF

Conditions

Workup

1. 1
   OtherDMF was then removed in vacuo
2. 2
   workup.DISSOLUTIONthe residue was dissolved in 300 ml of ethyl acetate
3. 3
   WashThe solution was washed with water
4. 4
   Dryingthe organic layer was dried over MgSO4
5. 5
   OtherAfter concentration of the solution and recrystallization from ethyl acetate/hexane
6. 6
   Otherthe solid product 5'-O-(4,4'-dimethoxy)-3'-(tert-butyldimethylsilyl)thymidine 17 was used directly for the next reaction

Procedure

To a solution of 13.0 g (23.9 mmol) 5'-O-(4,4'-dimethoxytrityl)thymidine 16 in 50 ml DMF was added 3.0 g (44 mmol) imidazole and 3.6 g (23.9 mmol) tert-butyl-dimethylsilyl chloride. The solution was stirred at room temperature for 3 hours. DMF was then removed in vacuo and the residue was dissolved in 300 ml of ethyl acetate. The solution was washed with water and the organic layer was dried over MgSO4. After concentration of the solution and recrystallization from ethyl acetate/hexane, the solid product 5'-O-(4,4'-dimethoxy)-3'-(tert-butyldimethylsilyl)thymidine 17 was used directly for the next reaction.

Source