Sodium Carbonate → 4'-Amino-3'-fluoro[1,1'-biphenyl]-2-carbaldehyde

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Reaction Steps

To a solution of 2-formylphenylboronic acid (5 g, 33.3 mmol) in THF (80 mL) was added 4-bromo-2-fluoroaniline (4.2 g, 22.2 mmol) and Na2CO3 (2M, 80 mL) and then was bubbled with nitrogen for 10 minutes. After Pd(PPh3)4 (1.54 g, 1.33 mmol) was added, the resulting mixture was refluxed under nitrogen for 4 hours. The THF layer was separated, filtered through a pad of silica gel, and washed with THF to give 80 mL solution of 4(2′-formylphenyl)-2-fluoroaniline in THF. MS(CI) m/z 233 (M+NH4, 100%). To the filtrate (15 mL from total 80 mL) was added Me2NH.HCl (0.68 g, 8.33 mmol) and the resulting mixture was refluxed for 2 hours. The mixture was cooled to room temperature, and to it was added MeOH (5 mL) and then NaBH4 (0.32 g, 8.33 mmoL). After being stirred at 50° C. for 1 hour, the mixture was cooled to room temperature again and quenched with 1N HCl to pH 1. The aqueous layer was separated, neutralized with 50% NaOH to pH 12, and extracted with EtOAc. The EtOAc layer was dried over MgSO4, concentrated, and purified by silica gel chromatography eluted with EtOAc to give 4-(2′-N,N-dimethylaminomethylphenyl)-2-fluoroaniline (0.89 g, 87.5%). 1H NMR (CDCl3) δ 7.49 (dd, J=8.8 Hz, J=1.8 Hz, 1H), 7.31-7.21 (m, 3H), 7.14 (dd, J=12.1 Hz, J=1.8 Hz, 1H), 6.97 (dd, J=8.1 Hz, J=1.5 Hz, 1H), 6.80 (t, J=8.8 Hz, 1H), 3.76 (bs, 2H), 3.34 (s, 2H), 2.17 (s, 6H); 19F NMR (CDCl3) δ −136.19; MS(ES+) m/z 245.2 (M+H, 100).

Provenance & Evidence