反应详情

The crude 2,2-diethoxy-N-(3-fluorobenzyl)acetimidamide (22 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. Then this mixture was quenched with ice (1 Kg), and a 12 N NaOH solution (400 mL) was added. The final pH of 9˜10 was reached. The 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 purified by silica gel chromatography (EtOAc/Hexane=1/1) and afforded the title compound (330 mg, 2.5% yield based on m-fluorobenzylamine) as a yellow solid. 1H NMR (300 MHz, CDCl3): 9.17 (s, 1H), 8.66 (s, 1H), 8.01˜8.07 (m, 2H), 7.68 (dd, J=2.4, and 8.7 Hz, 1H), 7.58 (m, 1H); MS: m/z 163.1 (M+H+).

1. stirringThe mixture was stirred at room temperature for 48 hours
2. customThen this mixture was quenched with ice (1 Kg)
3. additiona 12 N NaOH solution (400 mL) was added
4. extractionThe suspension was extracted with CH2Cl2 (5×2 L)
5. washwashed with brine (500 mL)
6. dry with materialdried over anhydrous Na2SO4
7. filtrationfiltered
8. concentrationconcentrated to dryness
9. customThe crude material was purified by silica gel chromatography (EtOAc/Hexane=1/1)