Reaction #554617

Reaction equation

NaHCO3

N6-Benzoyl-5′-O-tert-butyldimethylsilyl-2′-deoxyadenosine

DMSO

acetic anhydride

→

N6-benzoyl-3′-O -(methylthiomethyl)-5′-O-(tert-butyldimethylsilyl)-2′-deoxyadenosine

Yield 71.0%

N6-Benzoyl-3′-O-(methylthiomethyl)-5′-O-(tert-butyldimethylsilyl)-2′-deoxyadenosine

Yield 71.0%

Solvents

acetic acid

Conditions

Workup

1. 1
   Extractionextracted with CH2Cl2 (3×100 mL)
2. 2
   ExtractionThe combined organic extract
3. 3
   Washwas then washed with a saturated NaHCO3 solution (100 mL)
4. 4
   Dryingdried over Na2SO4
5. 5
   Concentrationconcentrated under vacuum
6. 6
   OtherThe resultant yellowish oil was then purified on silica gel column (Hex: EtOAc/1:1 to 1:4)

Procedure

3.0 g N6-Benzoyl-5′-O-tert-butyldimethylsilyl-2′-deoxyadenosine (5a) (6.38 mmol) was dissolved in a mixture consisting of 11.96 mL DMSO, 5.46 mL acetic acid, and 17.55 mL acetic anhydride and stirred at room temperature for 48 h. The reaction mixture was then neutralized treating with a sufficient amount of saturated NaHCO3 solution and extracted with CH2Cl2 (3×100 mL). The combined organic extract was then washed with a saturated NaHCO3 solution (100 mL), dried over Na2SO4, and concentrated under vacuum. The resultant yellowish oil was then purified on silica gel column (Hex: EtOAc/1:1 to 1:4) to obtain the product N6-benzoyl-3′-O -(methylthiomethyl)-5′-O-(tert-butyldimethylsilyl)-2′-deoxyadenosine (6a) as white powder in 71% yield (2.4 g, Rf 0.6, EtOAc: hex/7:3). HR-MS: obs. m/z 530.2273, calcd. for C25H36O4N5SiS 530.2257 [M+H]+. 1H-NMR (CDCl3): δH 9.00 (s, 1H), 8.83 (s, 1H), 8.35 (s, 1H), 8.05 (d, J=7.6 Hz, 2H), 7.62 (m, 1H), 7.55 (m, 2H), 6.55 (t, J=7.19 Hz, 1H), 4.73 (m, 2H), 4.68 (m, 1H), 4.24 (m, 1H), 3.88 (dd, J=11.19, 3.19 Hz, 1H), 2.74-2.66 (m, 2H), 2.35 (s, 3H), 0.94 (s, 9H) and 0.13 (s, 6H) ppm.

Source