反应详情

温度

0 °C

Sodium methoxyacetate (0.739 g, 6.6 mmol), prepared from methoxyacetic acid and NaOH in EtOH, is dissolved in 3.3 mL of DMF and cooled to 0° C. Methoxyacetyl chloride (0.39 mL, 4.0 mmol) is added dropwise. The mixture is stirred for 15 min at ambient temperature. 4-Benzyloxy-2-hydroxy-5-nitrobenzaldehyde (0.360 g, 1.32 mmol) is added and the solution refluxed for 3 h. After cooling to ambient temperature, EtOAc is added and the mixture is washed with 10% aqueous HCl, water, and sat. NaCl, then dried over sodium sulfate. The solvent is removed under reduced pressure and the residue purified by recrystallization from EtOAc to afford 7-benzyloxy-3-methoxy-6-nitrochromen-2-one as a yellow solid: mp=226-228° C.; 1H NMR (DMSO-d6) δ 8.27 (s, 1H), 7.48-7.35 (m, 7H), 5.36 (s, 2H), 3.82 (s, 3H); (M−H)−=326.

1. temperaturethe solution refluxed for 3 h
2. temperatureAfter cooling to ambient temperature
3. washthe mixture is washed with 10% aqueous HCl, water, and sat. NaCl
4. dry with materialdried over sodium sulfate
5. customThe solvent is removed under reduced pressure
6. customthe residue purified by recrystallization from EtOAc