Methanol → Methyl (3-cyano-4,5-dihydroxyphenyl)glyoxylate

Reaktionsgleichung

B(Br)(Br)Br.[C:5]([C:7]1[CH:8]=[C:9]([C:17](=[O:27])[C:18]([O:20][CH2:21]CCCCC)=[O:19])[CH:10]=[C:11]([O:15]C)[C:12]=1[O:13]C)#[N:6].CO>C(Cl)Cl>[C:5]([C:7]1[CH:8]=[C:9]([C:17](=[O:27])[C:18]([O:20][CH3:21])=[O:19])[CH:10]=[C:11]([OH:15])[C:12]=1[OH:13])#[N:6]

Komponenten

Versuchsvorschrift

4.8 ml of boron tribromide dissolved in 20 ml of methylene chloride are added dropwise while cooling with ice within 20 minutes to 4.0 g of hexyl (3-cyano-4,5-dimethoxyphenyl)glyoxylate dissolved in 100 ml of methylene chloride and the reaction mixture is stirred at room temperature for 18 hours. 40 ml of methanol are subsequently added dropwise thereto at -60°, the mixture is stirred at room temperature for 1 hour and evaporated. The residue is taken up in methanol. It is heated under reflux for 10 minutes, evaporated to dryness and dried in a high vacuum. The thus-obtained crude product is recrystallized from acetonitrile. There is obtained methyl (3-cyano-4,5-dihydroxyphenyl)glyoxylate of m.p. 252°.