Reaktion #3779

Reaktionsgleichung

2,3,4-Trimethoxybenzaldehyde

m-chloroperbenzoic acid

→

2,3,4-trimethoxyphenol

Ausbeute 51.1%

Lösungsmittel

methylene chloride

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturto heat
2. 2
   workup.DISTILLATIONAfter distilling off the solvents under reduced pressure
3. 3
   workup.DISSOLUTIONthe residue was dissolved in ethyl acetate (100 ml)
4. 4
   Waschenwashed in an aqueous saturated sodium hydrogen carbonate solution, in water and in a saturated sodium chloride solution
5. 5
   Trocknendried over anhydrous magnesium sulfate
6. 6
   workup.DISTILLATIONThen, the solvents were distilled off under reduced pressure
7. 7
   workup.ADDITIONTo the residue were added dioxane (15 ml)
8. 8
   workup.STIRRINGa 3N sodium hydroxide solution (15 ml), prior to stirring at room temperature for 30 minutes
9. 9
   Extraktionadjustment to acidity with dilute hydrochloric acid, followed by ethyl acetate extraction three times
10. 10
    WaschenThe organic phase was washed in water and in a saturated sodium chloride solution
11. 11
    Trocknendried over anhydrous magnesium sulfate
12. 12
    workup.DISTILLATIONfollowed by distillation of the solvents under reduced pressure
13. 13
    SonstigeThe residue was purified by silica gel column chromatography (developing solvent: hexane:ethyl acetate=3:1)

Vorschrift

2,3,4-Trimethoxybenzaldehyde (5 g) was suspended in anhydrous methylene chloride (50 ml), followed by addition of m-chloroperbenzoic acid (10 g; purity of 70%) to heat and stir the resulting mixture at 50° C. for 3 hours. After distilling off the solvents under reduced pressure, the residue was dissolved in ethyl acetate (100 ml) and washed in an aqueous saturated sodium hydrogen carbonate solution, in water and in a saturated sodium chloride solution, and dried over anhydrous magnesium sulfate. Then, the solvents were distilled off under reduced pressure. To the residue were added dioxane (15 ml) and a 3N sodium hydroxide solution (15 ml), prior to stirring at room temperature for 30 minutes and adjustment to acidity with dilute hydrochloric acid, followed by ethyl acetate extraction three times. The organic phase was washed in water and in a saturated sodium chloride solution and dried over anhydrous magnesium sulfate, followed by distillation of the solvents under reduced pressure. The residue was purified by silica gel column chromatography (developing solvent: hexane:ethyl acetate=3:1), to recover 2,3,4-trimethoxyphenol (2.4 g; yield of 51%). By 1H-NMR (90 MHz, CDCl3), the compound has the peaks shown below.

Quelle