2-Fluoro-N-methyl-4-nitrobenzamide → 4-Amino-2-fluoro-N-methylbenzamide

Reaction equation

[CH3:1][NH:2][C:3](=[O:14])[C:4]1[CH:9]=[CH:8][C:7]([N+:10]([O-])=O)=[CH:6][C:5]=1[F:13]>C(OCC)(=O)C.C(O)(=O)C.[Fe]>[CH3:1][NH:2][C:3](=[O:14])[C:4]1[CH:9]=[CH:8][C:7]([NH2:10])=[CH:6][C:5]=1[F:13]

Participants

Procedure

A mixture of N-methyl-2-fluoro-4-nitrobenzamide (52a) (2.89 g, 14.6 mmol) and iron (5.04 g, 90 mmol) in ethyl acetate (40 ml) and acetic acid (40 ml) was refluxed for 1 hour. The solid particles were filtered off. The filtrate was washed with water and extracted with ethyl acetate. The organic layer was dried over MgSO4, concentrated and chromatographed (dichloromethane:acetone, 95:5) to yield N-methyl-2-fluoro-4-aminobenzamide (52b) (2.3 g, 13.7 mmol, 94%) as an off-white solid. 1H NMR (acetone-d6, 400 MHz) δ 2.86 (d, J=4.3 Hz, 3H), 5.50 (bs, 2H), 6.37 (dd, J1=14.7 Hz, J2=2.1 Hz, 1H), 6.50 (dd, J=8.5, 2.1 Hz, 1H), 7.06 (bs, 1H), 7.68 (dd, J=8.8 8.8 Hz, 1H); 13C NMR (acetone-d6, 100 MHz) δ 25.8, 99.6 (d, J=13.8 Hz), 109.2 (d, J=12.8 Hz), 110.0 (d, J=1.6 Hz), 132.5 (d, J=4.8 Hz), 153.5 (d, J=12.6 Hz), 162.2 (d, J=242.5 Hz), 164.0 (d, J=3.1 Hz).