Hydrochloric Acid → Benzene, 1-bromo-4-(2-propenyl)-

HRID 1715385Notes

Reaction equation

HRID 1715385 reaction equation
Br[C:2]1[CH:7]=[CH:6][C:5]([Br:8])=[CH:4][CH:3]=1.[CH2:9](Br)[CH:10]=[CH2:11].Cl>C1COCC1.CCOCC>[CH2:11]([C:2]1[CH:7]=[CH:6][C:5]([Br:8])=[CH:4][CH:3]=1)[CH:10]=[CH2:9]

Participants

6

Reactant 3

HCID 313Hydrochloric AcidHCID 78041,4-Dibromobenzene3×HCID 7841Allyl bromide2×

Product 1

HCID 137529Benzene, 1-bromo-4-(2-propenyl)-Yield 61%

Reagents, catalysts & solvents 2

HCID 3283Diethyl EtherSolventHCID 8028TetrahydrofuranSolvent4×

Conditions

Temperature
0 °C

Procedure

Mg (8.76 g, 360 mmol) is suspended in THF (90 mL) under nitrogen in a three-necked flask equipped with a condenser and a dropping funnel. The dropping funnel is filled with 1,4-dibromobenzene (77.3 g, 327 mmol) in THF (40 mL). About 5% of the 1,4-dibromobenzene sol. is added carefully to the Mg-suspension and the reaction is started with the help of a heat gun. When the reaction starts, the 1,4-dibromobenzene sol. is added to such a speed so that the reaction mixture is refluxing gently (about 20 min). The mixture is stirred for further 30 min, and is cooled to 0° C. THF (100 mL) is added and the dropping funnel is filled with a sol. of allyl bromide (30.5 mL, 360 mmol) in THF (50 mL). The allyl bromide sol. is added slowly, maintaining the reaction temperature below 20° C. When the addition is complete, the mixture is stirred for further 30 min, while being cooled to 0° C. Aq. 1M HCl is added. The mixture is diluted with Et2O, and washed with aq. 1M HCl and brine. The combined aq. extracts are extracted back with Et2O. The combined org. extracts are dried over MgSO4, filtered, and the solvents are removed under reduced pressure. Distillation of the residue (11 mbar, 88-92° C.) yields the title compound (39.3 g, about 61%), together with another, unidentified impurity.

Workup

  1. customequipped with a condenser and a dropping funnel
  2. temperatureis refluxing gently (about 20 min)
  3. temperaturemaintaining the reaction temperature below 20° C
  4. additionWhen the addition
  5. stirringthe mixture is stirred for further 30 min
  6. temperaturewhile being cooled to 0° C
  7. washwashed with aq. 1M HCl and brine
  8. extractionThe combined aq. extracts are extracted back with Et2O
  9. dry with materialextracts are dried over MgSO4
  10. filtrationfiltered
  11. customthe solvents are removed under reduced pressure
  12. distillationDistillation of the residue (11 mbar, 88-92° C.)

Sources & evidence

ORD record
ord-15316d2c549d4ef7b41aa74226c0890d
Source dataset
uspto-grants-2010_09
Patent number
US07799805B2

Reaction notes

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