Bromine → 7-Bromo-2-ethyl-4-methoxybenzoxazole

HRID 275803Notes

Reaction equation

HRID 275803 reaction equation
[CH2:1]([C:3]1[O:4][C:5]2[CH:11]=[CH:10][CH:9]=[C:8]([O:12][CH3:13])[C:6]=2[N:7]=1)[CH3:2].[Br:14]Br>CO>[Br:14][C:11]1[C:5]2[O:4][C:3]([CH2:1][CH3:2])=[N:7][C:6]=2[C:8]([O:12][CH3:13])=[CH:9][CH:10]=1

Participants

4

Reactant 2

HCID 24408BromineHCID 183166412-Ethyl-4-methoxybenzoxazole2×

Product 1

HCID 224566737-Bromo-2-ethyl-4-methoxybenzoxazole

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Conditions

Temperature
-78 °C

Procedure

2-Ethyl-4-methoxybenzoxazole (2.81 g) was dissolved in methanol (80 ml) under nitrogen and the solution cooled to −78° C. Bromine (0.73 ml) was added dropwise. The mixture was allowed to warm gradually to room temperature and stirred for 3.5 h. The methanol was evaporated in vacuo and the residue partitioned between ethyl acetate and aqueous sodium bicarbonate. The combined organic phases were washed with 5% aqueous sodium metabisulphite, evaporated onto silica and purified by flash chromatography eluting with 25%-50% ethyl acetate in hexane to give a mixture of the title compound and 2-ethyl-4-methoxybenzoxazole as a pale yellow liquid (2.28 g).

Workup

  1. temperatureto warm gradually to room temperature
  2. customThe methanol was evaporated in vacuo
  3. customthe residue partitioned between ethyl acetate and aqueous sodium bicarbonate
  4. washThe combined organic phases were washed with 5% aqueous sodium metabisulphite
  5. customevaporated onto silica
  6. custompurified by flash chromatography
  7. washeluting with 25%-50% ethyl acetate in hexane
  8. customto give

Sources & evidence

ORD record
ord-3b74867e9f394e5b92aaa56e9c97350d
Source dataset
uspto-grants-2002_03
Patent number
US06353010B1

Reaction notes

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