反应详情

To a solution of 4-amino-3-fluoro-2-((2-fluorophenyl)amino)-5-hydroxy benzoic acid (7.58 g, 27.08 mmol) in trimethyl orthoformate (50 mL) was added p-TsOH (233 mg, 1.35 mmol). The reaction mixture was stirred for 1 h and treated with water (300 mL). The precipitate was filtered off and the filter cake was washed with water to afford the desired product (7.22 g, 92% yield). 1H NMR (400 MHz, DMSO-d6): δ 8.28 (s, 1H), 8.27 (s, 1H), 8.24 (s, 1H), 7.14 (m, 1H), 7.11 (m, 1H), 7.04 (m, 1H), 6.85 (m, 1H).

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