反应详情

The crude 2,2-diethoxy-N-(4-methoxybenzyl)acetimidamide (23 g) was added dropwise to conc. sulfuric acid (200 mL) at 20˜25° C. with stirring. The mixture was stirred at room temperature for 48 hours and then quenched with ice (1 Kg). 12 N NaOH solution (400 mL) was added to give a final pH of 9˜10. The resulting suspension was extracted with CH2Cl2 (5×2 L). The organic layers were combined, washed with brine (500 mL), dried over anhydrous Na2SO4, filtered and concentrated to dryness. The crude material was further purified by silica gel chromatography (EtOAc/Hexane=1/1) and afforded the title compound (430 mg, 2.9% yield based on p-methoxybenzylamine) as a yellow solid. 1H NMR (300 MHz, DMSO-d6): 8.62 (s, 1H), 7.66 (d, J=9 Hz, 1H), 6.86 (d, J=2.4, 1H), 6.75 (dd, J=2.4 and 9 Hz, 1H), 6.52 (s, 1H), 5.83 (s, 1H), 3.83 (s, 3H); MS: m/z 175.1 (M+H+).

1. stirringThe mixture was stirred at room temperature for 48 hours
2. customquenched with ice (1 Kg)
3. addition12 N NaOH solution (400 mL) was added
4. customto give a final pH of 9˜10
5. extractionThe resulting suspension was extracted with CH2Cl2 (5×2 L)
6. washwashed with brine (500 mL)
7. dry with materialdried over anhydrous Na2SO4
8. filtrationfiltered
9. concentrationconcentrated to dryness
10. customThe crude material was further purified by silica gel chromatography (EtOAc/Hexane=1/1)