反应详情

2-(2-Hydroxyethylamino)-3-nitrobenzoic acid (5.14 g, 22.7 mmol) was dissolved in methanol (200 mL) and concentrated H2SO4 (10 mL) was added. The mixture was heated at reflux for 2.5 h. The solvent was removed at reduced pressure. The residue was treated with water (100 ml) and extracted with ethyl acetate (3×150 mL). The combined organic phase was dried and concentrated. Purification by column chromatography on silica using heptane ethyl acetate 1:1 as an eluent afforded methyl 2-[(2-hydroxyethyl)amino]-3-nitrobenzoate, 3.92 g (72%). MS NISI) m/z 241 [M+H]. 1H NMR (400 MHz, CDCI3) δ ppm 3.12 (t, J=5.10 Hz, 2H), 3.84 (t, J=5.15 Hz, 2H), 3.91 (s, 3H), 6.69 (t, J=7.96 Hz, 1H), 7.95 (dd, J=8.34, 1.52 Hz, 1H), 8.08 (dd, J=7.83, 1.52 Hz, 1H).

1. temperatureThe mixture was heated
2. temperatureat reflux for 2.5 h
3. customThe solvent was removed at reduced pressure
4. additionThe residue was treated with water (100 ml)
5. extractionextracted with ethyl acetate (3×150 mL)
6. customThe combined organic phase was dried
7. concentrationconcentrated
8. customPurification by column chromatography on silica