反应详情

Bromo-tris-pyrrolidino-phosphonium hexafluorophosphate (0.874 g, 1.88 mmol, 1.1 equiv.) and diisopropyl ethyl amine (0.46 mL, 3.58 mmol, 2.1 equiv.) were added to a solution of 4-methoxy-2,3-dihydro-indole-1,6-dicarboxylic acid 1-tert-butyl ester (0.500 g, 1.7 mmol, 1 equiv.) in tetrahydrofuran (10 mL) and the mixture was shaken for 5 minutes at room temperature. 4-Amino-2-fluorobenzoic acid ethyl ester (3.433 g 1.88 mmol, 1.1 equiv.) was added and the mixture shaken at room temperature for 16 hours. The solvent was removed under vacuum and the residue dissolved in trifluoroacetic acid (10 mL) and shaken for 1 hour at room temperature. The solvent was removed under vacuum and the residue was purified by column chromatography (SiO2, 1:1 Hept/EtOAc to EtOAc). The fractions were combined to afford crude 2-fluoro-4-[(4-methoxy-2,3-dihydro-1H-indole-6-carbonyl)-amino]-benzoic acid ethyl ester, 0.476 g (27% yield), this material was taken onto the next step without further purification. LC @215 nm; Rt 1.17: 46%, m/z (ES+): 359 (M+H+.).

1. stirringthe mixture shaken at room temperature for 16 hours
2. customThe solvent was removed under vacuum
3. dissolutionthe residue dissolved in trifluoroacetic acid (10 mL)
4. stirringshaken for 1 hour at room temperature
5. customThe solvent was removed under vacuum
6. customthe residue was purified by column chromatography (SiO2, 1:1 Hept/EtOAc to EtOAc)