反应详情

温度

80 °C

To a stirred solution of 3,4-diamino-benzoic acid methyl ester (236, 2 g, 12.03 mmol) in isopropanol (50 mL) was added oxaldehyde as a 40% solution in water (13.23 mmol, 1.52 mL). The reaction mixture was heated at 80° C. for 2 hours, the solvent was removed under reduced pressure and the residue was dried under vacuum to yield 237a as a yellow solid (2.09 g, 93% yield). 1H NMR: (DMSO) δ 9.01 (s, 2H), 8.54 (d, J=1.6 Hz, 1H), 8.23 (dd, J=8.6, 2.0 Hz, 1H), 8.14 (dd, J=8.6, 0.6 Hz, 1H), 3.35 (s, 3H).

1. customthe solvent was removed under reduced pressure
2. customthe residue was dried under vacuum