Reaction #1994271

Reaction equation

imidazole

( 1 )

5-[3-(2,2,2-trifluoroacetamido)-prop-1-ynyl]-2′-deoxyuridine

t-butyldimethylsilylchloride

→

( 2 )

5′-O-(tert-butyidimethylsilyl)-5-[3-(2,2,2-trifluoroacetamido)-prop-1-ynyl]-2′-deoxyuridine

Solvents

DMF

Conditions

Workup

1. 1
   OtherThe reaction was quenched with sat. aq. NaCl solution
2. 2
   workup.ADDITIONEtOAc (25 ml) was added to the reaction mixture
3. 3
   Extractionthe aqueous layer was extracted with EtOAc three times
4. 4
   DryingAfter drying the combined organics (MgSO4)
5. 5
   Otherthe solvent was removed under vacuum
6. 6
   OtherPurification by chromatography on silica (EtOAc:petroleum ether 8:2)

Procedure

To a solution of (1) (656 mg, 1.74 mmol) in dry DMF (15 ml) was added t-butyldimethylsilylchloride (288 mg, 1.91 mmol) in small portions, followed by imidazole (130 mg, 1.91 mmol). The reaction was followed by TLC and was completed after stirring for 8 h at room temperature. The reaction was quenched with sat. aq. NaCl solution. EtOAc (25 ml) was added to the reaction mixture and the aqueous layer was extracted with EtOAc three times. After drying the combined organics (MgSO4), the solvent was removed under vacuum. Purification by chromatography on silica (EtOAc:petroleum ether 8:2) gave (2) as slightly yellow crystals (676 mg, 83%). 1H NMR (d6 DMSO) δ 0.00 (s, 6H, CH3), 0.79 (s, 9H, tBu), 1.93-2.00 (m, 1H, H-2′), 2.06-2.11 (m, 1H, H-2′), 3.63-3.75 (m, 2H, H-5′), 3.79-3.80 (m, 1H, H-4′), 4.12-4.14 (m, 3H, H-3′, CHO, 5.22 (d, J=4.1 Hz, 1H, OH), 6.03 (t, J=6.9 Hz, 1H, H-1′), 7.86 (s, 1H, H-6), 9.95 (t, J=5.4 Hz, 1H, NH), 11.61 (br s, 1H, NH). Mass (−ve electrospray) calcd for C20H28F3N3O6Si 491.17. Found 490.

Source