Ammonium Chloride → Ethyl 6-amino-5-bromobenzofuran-3-carboxylate

反応式

[Br:1][C:2]1[C:3]([N+:16]([O-])=O)=[CH:4][C:5]2[O:9][CH:8]=[C:7]([C:10]([O:12][CH2:13][CH3:14])=[O:11])[C:6]=2[CH:15]=1.[NH4+].[Cl-]>CO.C1COCC1.O.[Fe]>[NH2:16][C:3]1[C:2]([Br:1])=[CH:15][C:6]2[C:7]([C:10]([O:12][CH2:13][CH3:14])=[O:11])=[CH:8][O:9][C:5]=2[CH:4]=1

参加物

実験手順

A mixture of crude compound ethyl 5-bromo-6-nitrobenzofuran-3-carboxylate (95 g, 302 mmol), iron filings (50.67 g, 907 mmol) and NH4Cl (97 g, 1.82 mol) in MeOH-THF—H2O (2:2:1, 1000 mL) were stirred at reflux for 3 hours. After being filtered and concentrated in vacuum, the residue was purified by column chromatography (eluted with PE:EA from 20:1 to 10:1) to furnish ethyl 6-amino-5-bromobenzofuran-3-carboxylate (58.00 g, yield: 68%). 1H-NMR (400 MHz, DMSO-d6) δ 8.46 (s, 1H), 7.85 (s, 1H), 7.03 (s, 1H), 5.55 (br s, 2H), 4.31 (q, J=7.2 Hz, 2H), 1.32 (t, J=7.2 Hz, 3H).