反应详情

Step AH (2): 2-Bromo-5-methoxybenzaldehyde (1069 mg, 4.975 mmol) was dissolved in a mixture of methanol (20 mL) and triethylorthoformate (20 mL). p-Toluenesulfonic acid monohydrate (180.0 mg, 0.946 mmol) was added and the reaction mixture was stirred under reflux for 5 h. The reaction was quenched with aqueous NaHCO3 and extracted with DCM. The combined organic phases were dried over Na2SO4, filtered and concentrated in vacuum at the temperature, not exceeding 35° C. The residue was purified by silica gel chromatography to give 1-bromo-2-(dimethoxymethyl)-4-methoxybenzene (688.5 mg, 53%) as colorless oil. LC-MS (M+H)+=261.00. 1H NMR (CDCl3, 500 MHz) δ 7.42 (d, J=7.0 Hz, 1H) 7.16 (d, J=3.0 Hz, 1H) 6.76 (dd, J1=10 Hz, J2=3.0 Hz, 1H) 5.50 (s, 1H) 3.80 (s, 3H) 3.39 (s, 6H).

1. temperatureunder reflux for 5 h
2. customThe reaction was quenched with aqueous NaHCO3
3. extractionextracted with DCM
4. dry with materialThe combined organic phases were dried over Na2SO4
5. filtrationfiltered
6. concentrationconcentrated in vacuum at the temperature
7. customexceeding 35° C
8. customThe residue was purified by silica gel chromatography