反应详情

To a solution of 4-amino-3-fluoro-2-((2-fluorophenyl)amino)-5-hydroxy benzoic acid (7.58 g, 27.05 mmol) in trimethyl orthoformate (50 mL) was added p-TsOH (0.23 g, 1.35 mmol). The reaction mixture was stirred for 1 h and treated with water (200 mL). The precipitate was filtered off and the filter cake was washed with water to afford the desired product (7.22 g, 82.7% yield for two steps). 1H NMR (400 MHz, CDCl3): δ 8.28 (s, 1H), 8.27 (s, 1H), 8.24 (s, 1H), 7.14 (m, 1H), 7.05 (m, 2H), 6.86 (m, 1H).

1. filtrationThe precipitate was filtered off
2. washthe filter cake was washed with water