反応 #554619

反応方程式

NaHCO3

N4-benzoyl-5′-O-tert-butyldimethylsilyl-2′-deoxycytidine

DMSO

acetic anhydride

→

N4-benzoyl-3′-O-(methylthiomethyl)-5′-O-(tert-butyldimethylsilyl)-2′-deoxycytidine

収率 73.0%

N4-Benzoyl-3′-O-(methylthiomethyl)-5′-O-(tert-butyldimethylsilyl)-2′-deoxycytidine

収率 73.0%

溶媒

acetic acid

EtOAc

反応条件

後処理

1. 1
   workup.WAITDuring this period of time
2. 2
   抽出extracted with CH2Cl2 (3×100 mL)
3. 3
   抽出The combined organic extract
4. 4
   洗浄was then washed with saturated solution of NaHCO3
5. 5
   乾燥dried over Na2SO4
6. 6
   濃縮concentrated under vacuum
7. 7
   その他The product was then purified by silica gel column chromatography (EtOAc: hex/2:1 to 9:1)

実験手順

3.5 g N4-benzoyl-5′-O-tert-butyldimethylsilyl-2′-deoxycytidine (5c) (7.65 mmol) was dissolved in a mixture consisting of 14.7 mL DMSO, 6.7 mL acetic acid, and 21.59 mL acetic anhydride and stirred for 48 h at room temperature. During this period of time, a complete conversion to product was observed by TLC (Rf=0.4, EtOAc:hex/10:1). The mixture was then neutralized with a saturated NaHCO3 solution and extracted with CH2Cl2 (3×100 mL). The combined organic extract was then washed with saturated solution of NaHCO3 and dried over Na2SO4, and concentrated under vacuum. The product was then purified by silica gel column chromatography (EtOAc: hex/2:1 to 9:1) to obtain N4-benzoyl-3′-O-(methylthiomethyl)-5′-O-(tert-butyldimethylsilyl)-2′-deoxycytidine (6c) as white powder in 73% yield (2.9 g, Rf=0.6, EtOAc:hex/9:1). HR-MS: obs. m/z 506.2134, cald. for C24H36O5N3SiS [M+H]+. 506.2145. 1H-NMR (CDCl3): δH 8.43 (d, J=7.1 Hz, 1H), 7.93 (m, 2H), 7.64 (m, 1H), 7.54 (m, 3H), 6.30 (m, 1H), 4.62 & 4.70 (2Xd, J=11.59 Hz, 2H), 4.50 (m, 1H), 4.19 (m, 1H), 3.84 & 3.99 (2Xdd, J=11.59 & 2.79 Hz, 2H), 2.72 (m, 1H), 2.21 (m, 1H), 2.14 (s, 3H), 0.99 (s, 9H), and 0.16 (s, 6H) ppm.

出典