Sulfuric Acid → 1-(4-Methyl-3-cyclohexen-1-yl)cyclopentan-1-ol

HRID 1719838Notes

Reaction equation

HRID 1719838 reaction equation
[Mg].Br[CH2:3][CH2:4][CH2:5][CH2:6]Br.[CH3:8][C:9]1[CH2:14][CH2:13][CH:12]([C:15]([OH:17])=O)[CH2:11][CH:10]=1.S(=O)(=O)(O)O>O1CCCC1>[CH3:8][C:9]1[CH2:14][CH2:13][CH:12]([C:15]2([OH:17])[CH2:6][CH2:5][CH2:4][CH2:3]2)[CH2:11][CH:10]=1

Participants

6

Reactant 4

HCID 1118Sulfuric AcidHCID 80561,4-DibromobutaneHCID 203504-Methyl-3-cyclohexene-1-carboxylic AcidHCID 5462224Magnesium

Product 1

HCID 135578591-(4-Methyl-3-cyclohexen-1-yl)cyclopentan-1-ol

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent3×

Procedure

To a stirred suspension of 46.8 g of magnesium in 250 ml of tetrahydrofuran was added 182 g of 1,4-dibromobutane in 700 ml of dry tetrahydrofuran over 1 hour. The gently refluxing reaction mixture was maintained at reflux for 2 more hours and then cooled to room temperature. A solution of 100 g of the methyl ester of 4-methyl-3-cyclohexene-1-carboxylic acid in 20 ml of dry tetrahydrofuran was added at 20°-30° C. with cooling by an ice bath. The reaction mixture was stirred at room temperature for 2 days, and the excess Grignard reagent was decomposed by careful addition of dilute sulfuric acid. Most of the tetrahydrofuran was evaporated, and the reaction product was extracted with ether. The ether phase was washed successively with water and saturated NaCl solution, dried with MgSO4, and stripped to give 120 g of crude product as an oil. Multiple redistillation of the oil gave 32 g of product b.p. 90°-92° C. (0.5 mm).

Workup

  1. temperatureThe gently refluxing
  2. customreaction mixture
  3. temperaturewas maintained
  4. temperatureat reflux for 2 more hours
  5. temperaturewith cooling by an ice bath
  6. customMost of the tetrahydrofuran was evaporated
  7. extractionthe reaction product was extracted with ether
  8. washThe ether phase was washed successively with water and saturated NaCl solution
  9. dry with materialdried with MgSO4
  10. customto give 120 g of crude product as an oil
  11. distillationredistillation of the oil

Sources & evidence

ORD record
ord-f50c3d0f89ea45a8a5a9ba752c57d6ae
Source dataset
uspto-grants-1985_09
Patent number
US04542244

Reaction notes

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