反应详情

In a 100 mL round bottom flask ethyl 3-amino-4-hydroxybezoate (1.10 g, 6.07 mmol) and 4a (1.00 g, 2.98 mmol) were refluxed in ethanol (50 mL). After 2 h, the condenser was rearranged for distillation and ethanol (25 mL) was distilled off. The resulting solution was slowly poured into a vigorously stirred solution of ice cold water (200 mL) and citric acid (50 mg) giving a pink solid precipitate. The mixture was stirred for 10 min and then the solid was collected by filtration and rinsed with cold water to give 5h (1.23 g, 98.5%) after drying. The product was recrystallized from ethanol to give pale pink needles; m.p. 129.2-130° C. 1H NMR (600 MHz, CD2Cl2) δ 8.58 (s, 1H), 7.89 (dd, J=2.1, 8.7, 1H), 7.67 (d, J=2.1, 1H), 7.36-7.29 (m, 2H), 7.28-7.18 (m, 3H), 6.97 (d, J=8.7, 1H), 4.25 (q, J=7.1, 2H), 3.27 (s, 3H), 3.17 (s, 3H), 1.30 (t, J=7.1, 3H). 13C NMR (151 MHz, CD2Cl2) δ 165.40, 159.72, 156.82, 151.91, 136.06, 132.09, 130.86, 130.65, 129.49, 128.99, 128.83, 127.84, 125.70, 122.92, 117.65, 104.70, 103.11, 61.23, 32.02, 28.08, 14.24. MS (ES+) (m/z): [M+1]+ calculated for C23H22N3O5, 420.16. found 420.13.

1. distillationthe condenser was rearranged for distillation and ethanol (25 mL)
2. distillationwas distilled off
3. additionThe resulting solution was slowly poured into a vigorously stirred solution of ice cold water (200 mL) and citric acid (50 mg)
4. customgiving a pink solid precipitate
5. filtrationthe solid was collected by filtration
6. washrinsed with cold water