Methanol → Methyl 3-bromocinnamate, predominantly trans
Reaktionsgleichung
S(=O)(=O)(O)O.[Br:6][C:7]1[CH:8]=[C:9]([CH:15]=[CH:16][CH:17]=1)[CH:10]=[CH:11][C:12]([OH:14])=[O:13].[CH3:18]O>>[CH3:18][O:13][C:12](=[O:14])/[CH:11]=[CH:10]/[C:9]1[CH:15]=[CH:16][CH:17]=[C:7]([Br:6])[CH:8]=1Komponenten
4
Versuchsvorschrift
Add concentrated sulfuric acid (5.0 mL, 90 mmol) to a solution of 3-bromocinnamic acid (25.0 g, 110 mmol) in MeOH (250 mL). Heat the mixture to reflux for 5 h then cool to room temperature and concentrate under reduced pressure. Dilute the residue with water and extract with EtOAc. Concentrate the combined organic phase under reduced pressure and purify the residue by silica gel chromatography to provide 26 g of trans-3-(3-bromo-phenyl)-acrylic acid methyl ester.
Aufarbeitung
- temperatureHeat the mixture