Ethylene Glycol → 1,3-Dioxolane, 2-[2-(bromomethyl)phenyl]-2-methyl-

HRID 1784203Notes

Reaction equation

HRID 1784203 reaction equation
[CH3:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[C:8](=[O:10])[CH3:9].[CH2:11]([OH:14])[CH2:12]O.O.C1(C)C=CC(S(O)(=O)=O)=CC=1.[Br:27]N1C(=O)CCC1=O.N(C1(C#N)CCCCC1)=NC1(C#N)CCCCC1>C1C=CC=CC=1.CCOCC>[Br:27][CH2:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[C:8]1([CH3:9])[O:14][CH2:11][CH2:12][O:10]1

Participants

8

Reactant 5

HCID 174Ethylene GlycolHCID 113402-MethylacetophenoneHCID 67184N-bromobutanimideHCID 749781,1'-Azobis(cyclohexanecarbonitrile)HCID 521998p-Toluenesulfonic acid monohydrate

Product 1

HCID 109450651,3-Dioxolane, 2-[2-(bromomethyl)phenyl]-2-methyl-Yield 80%

Reagents, catalysts & solvents 2

HCID 241BenzeneSolventHCID 3283Diethyl EtherSolvent

Procedure

To a solution of 2′-methyl-acetophenone (2.68 g, 20.0 mmol) in benzene (100 mL) was added ethylene glycol (2.0 mL, 35.9 mmol) followed by p-toluenesulfonic acid monohydrate (0.39 g, 2.10 mmol). The reaction flask was topped with a Dean-Stark trap, and the mixture was heated to reflux overnight. The mixture was cooled to room temperature, diluted with Et2O (100 mL), washed with saturated aqueous NaHCO3 (5×20 mL) and brine (3×25 mL), dried (MgSO4), and concentrated. The resultant colorless oil (3.6 g) was dissolved in CCl4 (50 mL) and to this solution was added N-bromosuccinimide (3.76 g, 21.1 mmol) followed by 1,1′-azobis(cyclo-hexanecarbonitrile) (0.98 g, 3.99 mmol). The resultant mixture was refluxed for 5 hours then cooled to room temperature, filtered through filter paper, and concentrated. Purification of the crude material by column chromatography on silica gel (20:1:hexanes-EtOAc) provided 4.09 g (80%) of 2-(2-bromomethyl-phenyl)-2-methyl-[1,3]dioxolane as a colorless oil. 1H NMR (CDCl3) δ 1.74 (s, 3H), 3.75-3.81 (m, 2H), 4.04-4.08 (m, 2H), 4.89 (s, 2H), 7.24-7.31 (m, 2H), 7.44-7.57 (m, 2H).

Workup

  1. temperaturethe mixture was heated
  2. temperatureto reflux overnight
  3. washwashed with saturated aqueous NaHCO3 (5×20 mL) and brine (3×25 mL)
  4. dry with materialdried (MgSO4)
  5. concentrationconcentrated
  6. dissolutionThe resultant colorless oil (3.6 g) was dissolved in CCl4 (50 mL) and to this solution
  7. temperaturethen cooled to room temperature
  8. filtrationfiltered
  9. filtrationthrough filter paper
  10. concentrationconcentrated
  11. customPurification of the crude material by column chromatography on silica gel (20:1:hexanes-EtOAc)

Sources & evidence

ORD record
ord-ac3d2913dff2459bb6045f47cb02c8fc
Source dataset
uspto-grants-2009_03
Patent number
US07501518B2

Reaction notes

Loading…