Hydrogen Bromide → 2-Bromo-2'-methylacetophenone

HRID 453684Notes

Reaction equation

HRID 453684 reaction equation
[CH3:1][C:2]1[CH:10]=[CH:9][CH:8]=[CH:7][C:3]=1[C:4](Cl)=[O:5].[N+](=[CH:13][Si](C)(C)C)=[N-].[BrH:18].CCOC(C)=O>C(#N)C.O>[Br:18][CH2:13][C:4]([C:3]1[CH:7]=[CH:8][CH:9]=[CH:10][C:2]=1[CH3:1])=[O:5]

Participants

7

Reactant 4

HCID 260Hydrogen BromideHCID 8857Ethyl AcetateHCID 702762-Methylbenzoyl chlorideHCID 167693Trimethylsilyldiazomethane

Product 1

HCID 124306762-Bromo-2'-methylacetophenoneYield 91%

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 6342AcetonitrileSolvent

Procedure

To a solution of 2-methylbenzoyl chloride (169 μl, 1.29 mmol) in dry acetonitrile (5 ml) and cooled at 0° C., under nitrogen atmosphere, was added (diazomethyl)-trimethylsilane (1.94 ml, 3.88 mmol, 2M in hexane). The reaction was stirred at room temperature for 15 hours, then it was cooled at 0° C. and 48% HBr (512 μl, 4.53 mmol) was slowly added. The reaction was stirred at room temperature for 3 hours. EtOAc and water were added, the organic layer was separated and the aqueous phase was neutralized with 1M NaOH and extracted with EtOAc. The combined organic layers were dried over Na2SO4, filtered and evaporated to dryness to obtain 2-bromo-1-o-tolylethanone (250 mg, 91% yield). This intermediate was used in the next step without any further purification.

Workup

  1. temperatureit was cooled at 0° C.
  2. stirringThe reaction was stirred at room temperature for 3 hours
  3. customthe organic layer was separated
  4. extractionextracted with EtOAc
  5. dry with materialThe combined organic layers were dried over Na2SO4
  6. filtrationfiltered
  7. customevaporated to dryness

Sources & evidence

ORD record
ord-8ce24daf63a84953aa6a934aad76d909
Source dataset
uspto-grants-2013_07
Patent number
US08492548B2

Reaction notes

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