Dimethyl Sulfate → 5-Bromo-1,2,3-trimethoxybenzene

Temperatur

10 °C

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.

1. temperatureThe mixture was refluxed for 3 h
2. temperatureThe mixture was refluxed for another 3 h
3. temperatureUpon cooling overnight
4. filtrationwas filtered off
5. dissolutiondissolved in 1.2 l of ether
6. filtrationThe ether solution was filtered
7. customto remove insoluble impurity
8. washwashed sequentially with 5% NaOH solution (200 ml), water (2×200 mL), and brine (200 mL)
9. dry with materialThe ether phase was dried over Na2SO4
10. customto give a off-white solid, which
11. customwas recrystallized in hexane (300 ml)

ORD-Eintrag

ord-8728cdf0d1c144e686d2423cb056c603

Quelldatensatz

uspto-grants-2005_02

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US06855657B2