B(Cl)(Cl)Cl.[F:5][C:6]1[C:11]([CH:12]=[O:13])=[C:10]([O:14]C)[C:9]([O:16][CH3:17])=[CH:8][CH:7]=1.O>ClCCl>[F:5][C:6]1[C:11]([CH:12]=[O:13])=[C:10]([OH:14])[C:9]([O:16][CH3:17])=[CH:8][CH:7]=11M boron trichloride in dichloromethane (25 ml; 25 mmol) was added to a solution of 6-fluoro-2,3-dimethoxy-benzaldehyde [Cantrell, Amanda S.; Engelhardt, Per; Hoegberg, Marita; Jaskunas, S. Richard; Johansson, Nils Gunnar; et al.; J. Med. Chem.; 39; 21; 1996; 4261-4274] (4.26 g; 23 mmol) in dichloromethane (30 ml) keeping the reaction temperature at −70° C. The reaction mixture stirred at room temperature overnight and hydrolyzed with water. The organic phase was separated, washed with water and evaporated in vacuo. The residue was chromatographed (silica gel, EA:Hex, 5:1) to give 3.72 g (94%) of 6-fluoro-2-hydroxy-3-methoxy-benzaldehyde as yellow crystals.
Wird geladen…
