Sulfuric Acid → Jones' reagent

HRID 364875Notes

Reaction equation

C(C1CC[CH:7]([CH:10]=[O:11])CC=1)(C)C.[CH:12]([C@H]1CC[C@H](C=O)CC1)(C)C.[S:23](=[O:27])(=[O:26])([OH:25])[OH:24].[O-2:28].[Cr+6:29].[O-2:30].[O-2:31]>CC(C)=O.O>[CH3:12][C:10]([CH3:7])=[O:11].[OH:26][S:23]([OH:27])(=[O:25])=[O:24].[O:28]=[Cr:29](=[O:31])=[O:30]

Participants

Conditions

Temperature: 10 °C

Procedure

A mixture of perillaldehyde (500 g) and 10% sulfuric acid (3 liters) was vigorously stirred for 3 hrs. at reflux (105° C.) under a nitrogen atmosphere. After cooling, the oily layer was separated from the acid, added to methanol (3 liters) and the resultant solution purged with nitrogen. Potassium hydroxide pellets (80 g) were fed into the solution, which was then refluxed (65° C.) for 2 hrs. under an atmosphere of nitrogen. The reaction mixture was then cooled to room temperature and concentrated to 1 liter. The concentrate was diluted with water (3 liters) and extracted with CH2Cl2 (1.5 liters). The extract was washed neutral with water and concentrated to 490 g of an oil which on distillation yielded 100 g of aldehydes; b.p. 65°-78° C. @ 3.5 mm; analysis: 62% 4-isopropyl-3-cyclohexene-1-carboxaldehyde and 7% trans-4-isopropylcyclohexane-1-carboxaldehyde. A solution was made of the aldehyde mixture in acetone (1 liter) and cooled to 10° C. Jones reagent was prepared from 57.5 ml conc. sulfuric acid, 250 ml water and 66.8 g of chromium (VI) oxide. The reagent (200 ml) was added to the solution at 10° C. over a period of 30 minutes. After an additional 15 minutes at 10° C. the acetone was removed by decantation and the residual chromium salts were washed with additional 200 ml acetone. The combined-acetone solution was concentrated to 500 ml, diluted with 5% aqueous sodium hydroxide (1 liter) and washed with CH2Cl2 (1 liter). The aqueous phase was acidified with 10% sulfuric acid (1 liter) and extracted with CH2Cl2. Concentration of the CH2Cl2 solution yielded a solid (70 g) which on crystallization from hexane (-70° C.) yielded 63 g of a crystalline material; m.p. 58°-60° C.; analysis: (CW 20M fused silica column, 190° C.) 87% 4-isopropyl-3-cyclohexene-1-carboxylic acid and 11% trans-4-isopropylcyclohexane-1-carboxylic acid.

Workup

customAfter an additional 15 minutes at 10° C. the acetone was removed by decantation
washthe residual chromium salts were washed with additional 200 ml acetone
concentrationwas concentrated to 500 ml
additiondiluted with 5% aqueous sodium hydroxide (1 liter)
washwashed with CH2Cl2 (1 liter)
extractionextracted with CH2Cl2

Sources & evidence

ORD record: ord-5715a0d45d194ccb867c8fc19c474048
Source dataset: uspto-grants-1986_08
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04606925

Reaction notes

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