Hydrochloric Acid → 1-Methyl-3-(3,5-dimethyl-phenyl)-cyclopentadiene

HRID 602846

Reaction equation

HRID 602846 reaction equation
Br[C:2]1[CH:7]=[C:6]([CH3:8])[CH:5]=[C:4]([CH3:9])[CH:3]=1.C([Li])CCC.[CH3:15][CH:16]1[CH2:20][CH2:19][CH2:18][C:17]1=O.Cl>CCCCCC.C(OCC)C>[CH3:15][C:16]1[CH2:20][CH:19]=[C:18]([C:2]2[CH:7]=[C:6]([CH3:8])[CH:5]=[C:4]([CH3:9])[CH:3]=2)[CH:17]=1

Participants

7

Reactant 4

HCID 313Hydrochloric AcidHCID 142652-MethylcyclopentanoneHCID 136357Benzene, 1-bromo-3,5-dimethyl-HCID 178418339Butyllithium

Product 1

HCID 866295691-Methyl-3-(3,5-dimethyl-phenyl)-cyclopentadieneYield 46%

Reagents, catalysts & solvents 2

HCID 3283Diethyl EtherSolvent2×HCID 8058HexaneSolvent2×

Procedure

1-Bromo-3,5-dimethylbenzene (13.6 g, 73.6 mmol) was dissolved in a mixed solution of hexane (150 mL) and diethyl ether (20 mL) and added dropwise at 0° C. with a solution (46.6 mL, 1.58M) of n-butyllithium in hexane. The solution was immediately warmed to room temperature, stirred night and day and added dropwise at −78° C. to a solution of 3-methyl-2-cyclopentanone (7.3 mL, 74 mmol) in diethyl ether (100 mL). The resultant solution was warmed to room temperature immediately after dropwise addition and stirred for 2 hours. After termination of the reaction, the reaction solution was added with dilute hydrochloric acid, stirred at room temperature for 30 minutes and then subjected to layer separation. The organic layer was dried with magnesium sulfate and then had the solvent distilled off under reduced pressure. The crude product was distilled under reduced pressure (125 to 127° C./0.5 mmHg) to obtain 1-methyl-3-(3,5-dimethyl-phenyl)-cyclopentadiene (6.2 g, yield: 46%).

Workup

  1. additionimmediately after dropwise addition
  2. stirringstirred for 2 hours
  3. customAfter termination of the reaction
  4. stirringstirred at room temperature for 30 minutes
  5. customsubjected to layer separation
  6. dry with materialThe organic layer was dried with magnesium sulfate
  7. distillationdistilled off under reduced pressure
  8. distillationThe crude product was distilled under reduced pressure (125 to 127° C./0.5 mmHg)

Sources & evidence

ORD record
ord-d148eed8c1fb41e79daedb2f1b5153da
Source dataset
uspto-grants-2011_03
Patent number
US07906599B2

Linked notes

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