反应详情

To a solution of 3,4-diethoxybenzoic acid (0.11 g; 0.52 mmol), and the product of Step A (0.09 g; 0.51 mmol) in anhydrous THF (2 ml), PyBroP (0.25 g; 0.54 mmol) was added followed by DIPEA (0.21 ml; 1.22 mmol), with stirring, at room temperature under N2. After 2 h of stirring, the mixture was diluted to 15 ml with EtOAc, washed with saturated NH4Cl (2×5 ml), brine, dried over anhydrous MgSO4 and filtered. The filtrate was evaporated to dryness under reduced pressure and the residue was suspended in anhydrous toluene (10 ml). To it 1M TBAF in THF (0.5 ml) was added and the reaction mixture was refluxed for 3 h under N2, cooled to room temperature and solvents were removed under reduced pressure. The residue was washed with H2O (5 ml) and the solid was purified by FCC (SiO2; CH2Cl2) to give the title compound (0.06 g; 34%) as colourless solid. 1H-NMR (CDCl3) 1.5 (m, 6H); 4.16-4.26 (m, 4H); 6.98 (d, 1H, J=8.5 Hz), 7.31-7.37 (m, 3H); 7.54 (d, 1H, J=8.1 Hz); 7.74 (d, 1H, J=2 Hz); 7.83 (d, 1H, J=8.4 Hz); 8.06 (dd, 1H, J=2, 8.4 Hz); 8.42 (s, 1H).

1. stirringAfter 2 h of stirring
2. washwashed with saturated NH4Cl (2×5 ml), brine
3. dry with materialdried over anhydrous MgSO4
4. filtrationfiltered
5. customThe filtrate was evaporated to dryness under reduced pressure
6. additionTo it 1M TBAF in THF (0.5 ml) was added
7. temperaturethe reaction mixture was refluxed for 3 h under N2
8. temperaturecooled to room temperature
9. customsolvents were removed under reduced pressure
10. washThe residue was washed with H2O (5 ml)
11. customthe solid was purified by FCC (SiO2; CH2Cl2)