反应详情

To a solution of 2,3-dihydrobenzo[b][1,4]dioxin-5-amine (Intermediate B3, 4.5 g, 30 mmol) in ethanol (50 mL) at room temperature was slowly added acetic anhydride (3.0 g, 30 mmol). After the addition was over, the mixture was stirred at room temperature for 5 minutes. The resulting suspension was concentrated to give the crude product, which was purified by silica gel column chromatography (petroleum ether/ethyl acetate 4/1) to afford the product N-(2,3-dihydrobenzo[b][1,4]dioxin-5-yl)acetamide (5.5 g, yield 95%). 1H NMR (400 MHz, CDCl3) δ ppm 9.12 (s, 1H), 7.44-7.46 (d, 1H, J=8.0 Hz), 6.71-6.75 (t, 1H, J=8.0 Hz), 6.59-6.61 (d, 1H, J=7.6 Hz), 4.23-4.30 (m, 4H), 2.06 (s, 3H).

1. customat room temperature
2. additionAfter the addition
3. concentrationThe resulting suspension was concentrated
4. customto give the crude product, which
5. customwas purified by silica gel column chromatography (petroleum ether/ethyl acetate 4/1)