Boron tribromide → 4-(p-Methoxyphenyl)-but-3-enoic acid

HRID 897139Notes

Reaction equation

HRID 897139 reaction equation
B(Br)(Br)Br.[CH3:5][O:6][C:7]1[CH:12]=[CH:11][C:10]([CH:13]2C[CH:14]2[CH2:16][C:17]([O:19]CC)=[O:18])=[CH:9][CH:8]=1>ClCCl.C(OCC)(=O)C>[CH3:5][O:6][C:7]1[CH:8]=[CH:9][C:10]([CH:13]=[CH:14][CH2:16][C:17]([OH:19])=[O:18])=[CH:11][CH:12]=1

Participants

5

Reactant 2

HCID 25134Boron tribromideHCID 20792287Ethyl 1-(p-methoxyphenyl)cyclopropane-2-acetate

Product 1

HCID 539491564-(p-Methoxyphenyl)-but-3-enoic acidYield 106.2%

Reagents, catalysts & solvents 2

HCID 6344DichloromethaneSolventHCID 8857Ethyl AcetateSolvent

Procedure

Boron tribromide (246 mL, 1 M) in dichloromethane was added slowly to a solution of ethyl 1-(p-methoxyphenyl)cyclopropane-2-acetate (60 g, 246 mmol) in dichloromethane (1L) at 0° C. and the reaction mixture was stirred at room temperature for 18 h. It was cooled to 0° C. and was quenched with excess ethanol. The reaction mixture was concentrated and the residue in ethyl acetate (1 L) was washed with saturated sodium bicarbonate (500 mL), washed with brine (500 mL), dried and was concentrated. The residue was purified by passing through a thick pad of silica and eluting with 20% ethyl acetate in hexane to afford 50.2 g (89%) of the desired product. 1H NMR (CD3OD) δ 6.93 (d, 2H, J=8.6 Hz), 6.71 (d, 2H, J=8.6 Hz), 4.15(q, 2H, J=7.1 Hz), 2.37 (d, 2H, J=7.2 Hz), 1.66-1.71 (m,1H), 1.23-1.28 (m, 4H), 0.87-0.91 (m, 1H), 0.75-0.79 (m, 1H).

Workup

  1. temperatureIt was cooled to 0° C.
  2. customwas quenched with excess ethanol
  3. concentrationThe reaction mixture was concentrated
  4. washthe residue in ethyl acetate (1 L) was washed with saturated sodium bicarbonate (500 mL)
  5. washwashed with brine (500 mL)
  6. customdried
  7. concentrationwas concentrated
  8. customThe residue was purified
  9. washeluting with 20% ethyl acetate in hexane

Sources & evidence

ORD record
ord-084aba140f004d1e81a363bfbbebe1bc
Source dataset
uspto-grants-2005_07
Patent number
US06921767B2

Reaction notes

Loading…