(+-)-alpha-Pinene → (1S-trans)-2-methyl-5-(1-methylvinyl)cyclohex-2-en-1-ol

A well stirred solution of benzoyl peroxide (24.0 g), cuprous chloride (0.2 g), cupric benzoate (1.5 g) and alpha-pinene (28.0 g) in acetonitrile (150 ml) is heated on an oil bath at 65° ± 5° for 24 hours. The acetonitrile is removed by evaporation under vacuum (water pressure) at 40°. Excess alpha-pinene is recovered by continuing the evaporation at 75° (3 mm). The resulting blue-green slurry is dissolved in 100 ml ether and the solution filtered to remove the cupric benzoate. The filtrate is washed with 2N HCl (2 × 30 ml), distilled water (3 × 30 ml) and then the ether removed by evaporation. This gives a straw colored oil which is dissolved in a solution of methanol (200 ml), water (50 ml), NaOH (10 g), and hydroylzed by refluxing 1 hour. Removal of the methanol affords an aqueous suspension which is diluted with water (100 ml) and steam distilled. The distillate is extracted with ether (4 × 20 ml). This organic solution is dried over magnesium sulphate and evaporated to yield crude trans-carveol (9.2 g). Distillation affords pure material, b.p. 106°-110°C (10 mm).

1. customThe acetonitrile is removed by evaporation under vacuum (water pressure) at 40°
2. customExcess alpha-pinene is recovered
3. customthe evaporation at 75° (3 mm)
4. dissolutionThe resulting blue-green slurry is dissolved in 100 ml ether
5. filtrationthe solution filtered
6. customto remove the cupric benzoate
7. washThe filtrate is washed with 2N HCl (2 × 30 ml)
8. distillationdistilled water (3 × 30 ml)
9. customthe ether removed by evaporation
10. customThis gives a straw colored oil which
11. temperaturehydroylzed by refluxing 1 hour
12. customRemoval of the methanol
13. customaffords an aqueous suspension which
14. distillationdistilled
15. extractionThe distillate is extracted with ether (4 × 20 ml)
16. dry with materialThis organic solution is dried over magnesium sulphate
17. customevaporated

ORD record

ord-c8bd3c21d8284b2bb7cacc00061b71fb

Source dataset

uspto-grants-1976_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US03956404