Reaktion #52140

Reaktionsgleichung

4-bromo-2,6-dimethoxy-phenol

NaOH

dimethyl sulfate

→

18

Ausbeute 79.0%

3,4,5-trimethoxybromobenzene

Ausbeute 79.0%

Lösungsmittel

H2O

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe mixture was refluxed for 3 h
2. 2
   TemperaturThe mixture was refluxed for another 3 h
3. 3
   TemperaturUpon cooling overnight
4. 4
   Filtrationwas filtered off
5. 5
   workup.DISSOLUTIONdissolved in 1.2 l of ether
6. 6
   FiltrationThe ether solution was filtered
7. 7
   Sonstigeto remove insoluble impurity
8. 8
   Waschenwashed sequentially with 5% NaOH solution (200 ml), water (2×200 mL), and brine (200 mL)
9. 9
   TrocknenThe ether phase was dried over Na2SO4
10. 10
    Sonstigeto give a off-white solid, which
11. 11
    Sonstigewas recrystallized in hexane (300 ml)

Vorschrift

A mixture of 74 g (0.32 mol) of 4-bromo-2,6-dimethoxy-phenol 17 and 32 g (0.8 mol) of NaOH in 850 ml of H2O was cooled to 10° C. and 45 ml (0.48 mmol) of dimethyl sulfate was added. The mixture was refluxed for 3 h and an equal amount of dimethyl sulfate (total 0.96 mol) was then added. The mixture was refluxed for another 3 h. Upon cooling overnight, the gray product solidified and was filtered off and dissolved in 1.2 l of ether. The ether solution was filtered to remove insoluble impurity and washed sequentially with 5% NaOH solution (200 ml), water (2×200 mL), and brine (200 mL). The ether phase was dried over Na2SO4 to give a off-white solid, which was recrystallized in hexane (300 ml) to give 62.3 g (79%) of 18.

Quelle