Sodium Sulfite → Methyl 2-bromo-3,5-dimethoxybenzoate

Reaktionsgleichung

[CH3:1][O:2][C:3](=[O:14])[C:4]1[CH:9]=[C:8]([O:10][CH3:11])[CH:7]=[C:6]([O:12][CH3:13])[CH:5]=1.C1C(=O)N([Br:22])C(=O)C1.[O-]S([O-])=O.[Na+].[Na+]>CC#N>[CH3:1][O:2][C:3](=[O:14])[C:4]1[CH:5]=[C:6]([O:12][CH3:13])[CH:7]=[C:8]([O:10][CH3:11])[C:9]=1[Br:22]

Komponenten

Versuchsvorschrift

3,5-Dimethoxy-benzoic acid methyl ester (4.0 g) was dissolved in MeCN (28 mL), and NBS (4.4 g) was added at 0° C. After stirring at room temperature for 3 hours, saturated Na2SO3 (15 mL) was added. The mixture was evaporated under vacuum and extracted with ether (1×, 500 mL). After the solvent was removed, the crude material was subjected to silica gel chromatography using effluent of 10-40% ethyl acetate and hexanes. The fractions containing product were combined and the solvent was removed under reduced pressure to provide 2-bromo-3,5-dimethoxy-benzoic acid methyl ester (5.2 g, 93%) as a clear oil.