反应详情

To a stirred solution of sodium t-butoxide (577 mg, 6 mmol) in anhydrous THF (15 ml) at room temperature was added, dropwise, dimethyl oxalate (472 mg, 4 mmol) in THF (7 ml) followed by 5-acetyl-1,3-dibenzyluracil (2a) (669 mg, 2 mmol) in THF (8 ml). The resulting mixture was stirred at room temperature for 4 h and then was acidified to pH=2. THF was evaporated. The residue in CH2Cl2 (100 ml) was washed with brine (20 ml) and purified by column chromatography (hexane:ethyl acetate, 2:1). The appropriate fraction was concentrated and crystallized from ethanol to give 254 mg of a yellow solid. Yield was 29.1%. Mp. 158-159° C. 1HNMR (CDCl3): 15.04 (s, br, 1H), 8.36 (s, 1H), 7.72 (s, 1H), 7.29-7.49 (m, 10H), 5.18 (s, 2H), 5.05 (s, 2H), 3.92 (s, 3H). 13CNMR (CDCl3): 185.7, 168.8, 162.4, 159.7, 150.5, 148.5, 136.0, 134.0, 129.4, 129.1, 129.0, 128.5, 128.3, 127.9, 109.0, 101.6, 53.7, 53.2, 45.0. FAB-HRMS: [M+H]+ calcd. for C23H21N2O6 421.1400, found 421.1418.

1. customTHF was evaporated
2. washThe residue in CH2Cl2 (100 ml) was washed with brine (20 ml)
3. custompurified by column chromatography (hexane:ethyl acetate, 2:1)
4. concentrationThe appropriate fraction was concentrated
5. customcrystallized from ethanol