反应详情

温度

20 °C

To an ice-cold CH2Cl2 (60 mL) solution of DCC (9.78 g, 47.34 mmol), t-BuOH (17.54 g, 0.24 mol) and DMAP (0.29 g, 2.37 mmol); a CH2Cl2 (40 mL) solution of 2 (16.00 g, 47.34 mmol) was added slowly over 20 min. Then reaction mixture was allowed to stir 1 h at 0° C. and 10 h at 20° C. Precipitated urea was then filtered off and the filtrate evaporated in vacuo. The residue was taken up in CH2Cl2, and if necessary, filtered free of any further precipitated urea. The CH2Cl2 solution was washed twice with 10% citric acid solution and with saturated NaHCO3 solution, and then dried over Na2SO4. The residue obtained after evaporation of CH2Cl2 was purified by column chromatography to obtain the product as a clear viscous oil (15.67 g, 84% yield). 1H NMR (300 MHz, CDCl3) δ7.26 (5H), 5.53 (1H), 5.45 (1H), 5.02 (2H), 4.26-4.18 (1H), 3.59-3.46 (2H), 1.38 (9H), 1.37 (9H); 13C NMR (75 MHz, CDCl3) δ 169.9, 156.8, 155.8, 136.6, 128.7, 128.3, 82.8, 80.1, 66.9, 54.7, 43.3, 28.5, 28.1; ESI-LRMS m/z 395.2 (M+H)+, 417.2 (M+Na)+.

1. customThen reaction mixture
2. filtrationPrecipitated urea was then filtered off
3. customthe filtrate evaporated in vacuo
4. filtrationif necessary, filtered free of
5. customany further precipitated urea
6. washThe CH2Cl2 solution was washed twice with 10% citric acid solution and with saturated NaHCO3 solution
7. dry with materialdried over Na2SO4
8. customThe residue obtained
9. customafter evaporation of CH2Cl2
10. customwas purified by column chromatography