反应详情

Thymine (0.63 g, 5 mmol) was added to 2-acetoxyethyl acetoxymethyl ether (1.32 g, 7.5 mmol) dissolved in 2 (15 mL). The reaction mixture was stirred at room temperature and N,O-bis(trimethylsilyl)acetamide (2.96 mL, 12 mmol) was added dropwise. After 3 hours of stirring, the clear solution was cooled to 0° C., and SnCl4 (0.12 mL, 1 mmol) was added. The reaction mixture was allowed to come to room temperature and stirred overnight. A mixture of saturated aqueous NaHCO3 (25 mL) and CHCl3 (50 mL) was prepared and cooled in ice. The reaction mixture was added slowly with vigorous stirring; a white foam formed immediately. After filtration, the aqueous layer was further extracted with ethyl acetate (3×25 mL) and CHCl3 (25 mL), and the combined organic layers were dried over anhydrous Na2SO4. After filtration of drying agent and removal of solvents in vacuo, an oily liquid was obtained. It was purified on a silica gel column using 2:1 CHCl3/CH3COCH3 as the eluent to give the desired product. Yield 36%; Wt. 4.0 g; mp 105°-107° C.; 1H NMR (DMSO-d6) 1.8 (s, CH3 C5 thymine), 2.0 (s, CH3 CO), 3.65 (m, CO O CH2 CH2), 4.1 (m, CO O CH2 CH2), 5.05 (s, O CH2 N) , 7.55 (s, H C6 thymine), 11.3 (s, HN thymine).

1. stirringAfter 3 hours of stirring
2. temperaturethe clear solution was cooled to 0° C.
3. customto come to room temperature
4. stirringstirred overnight
5. customwas prepared
6. temperaturecooled in ice
7. additionThe reaction mixture was added slowly with vigorous stirring
8. customa white foam formed immediately
9. filtrationAfter filtration
10. extractionthe aqueous layer was further extracted with ethyl acetate (3×25 mL) and CHCl3 (25 mL)
11. dry with materialthe combined organic layers were dried over anhydrous Na2SO4
12. filtrationAfter filtration
13. customof drying
14. customagent and removal of solvents in vacuo
15. customan oily liquid was obtained
16. customIt was purified on a silica gel column