2-Pyrrolidone → Methyl 4-(2-bromopropanoyl)benzoate

HRID 606595Notes

Reaction equation

HRID 606595 reaction equation
[CH3:1][O:2][C:3](=[O:14])[C:4]1[CH:9]=[CH:8][C:7]([C:10](=[O:13])[CH2:11][CH3:12])=[CH:6][CH:5]=1.C1CNC(=O)C1.[Br:21][Br-]Br.N1CCCC1=O>C1COCC1>[CH3:1][O:2][C:3](=[O:14])[C:4]1[CH:9]=[CH:8][C:7]([C:10](=[O:13])[CH:11]([Br:21])[CH3:12])=[CH:6][CH:5]=1

Participants

4

Reactant 2

HCID 120252-PyrrolidoneHCID 15666905Methyl 4-propanoylbenzoate

Product 1

HCID 20395191Methyl 4-(2-bromopropanoyl)benzoateYield 97.7%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

4-Propionyl-benzoic acid methyl ester (744 mg, 3.87 mmol), pyrrolidone hydrotribromide (1.98 g), and 2-pyrrolidinone (380 mg, 4.5 mmol) in THF (38 mL) were heated at 50° C. under nitrogen for 3 h. The mixture was cooled, filtered, concentrated, and then redissolved in ether (50 mL). The ether solution was washed successively with water (20 mL), saturated aqueous sodium thiosulphate (20 mL), saturated aqueous NaCl (20 mL), and water (20 mL), dried and evaporated to give crude 4-(2-Bromo-propionyl)-benzoic acid methyl ester as a yellow oil (1.025 g) that was used directly in the Hantzsch coupling. This material contained 91% of the desired bromoketone, 5% starting material, and 4% 4-bromo-1-butanol, as determined by 1H NMR.

Workup

  1. temperatureThe mixture was cooled
  2. filtrationfiltered
  3. concentrationconcentrated
  4. dissolutionredissolved in ether (50 mL)
  5. washThe ether solution was washed successively with water (20 mL), saturated aqueous sodium thiosulphate (20 mL), saturated aqueous NaCl (20 mL), and water (20 mL)
  6. customdried
  7. customevaporated

Sources & evidence

ORD record
ord-703ac03a2b1d40b6bd48794ad9510bee
Source dataset
uspto-grants-2011_03
Patent number
US07915300B2

Reaction notes

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