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

Beteiligte Stoffe

Reaktionsschritte

4-(2′-N,N-Dimethylaminomethylphenyl)-2-fluoroaniline: To a solution of 2-formylphenylboronic acid (5 g, 33 mmol) in THF (80 mL) was added 4-bromo-2-fluoroaniline (4.2 g, 22 mmol) and sodium carbonate (2 M, 80 mL) and then was bubbled with nitrogen for 10 min. After Pd(PPh3)4 (1.54 g, 1.33 mmol) was added, the resulting mixture was refluxed under nitrogen for 4 h. The THF layer was separated and filtered through a pad of silica gel. The pad was washed with THF to give an 80 mL solution of 4(2′-formylphenyl)-2-fluoroaniline in THF. To the filtrate (15 mL from total 80 mL) was added Me2NH.HCl (0.68 g, 8.3 mmol) and the resulting mixture was refluxed for 2 h. The mixture was cooled to rt and MeOH (5 mL) was added followed by NaBH4 (0.32 g, 8.3 mmoL). After being stirred at 50° C. for 1 hour, the mixture was cooled to rt and quenched with 1 N 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 SiO2 chromatography eluted with EtOAc to give 54a (0.89 g, 88% yield); [M+H]+=245.2; 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. This material was converted to the bis-HCl salt by dissolving a sample in a minimum volume of methanol and adding 2.2 equivalents of 1.0 M HCl in diethyl ether followed by removal of the solvent under reduced pressure.

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