Betulin → (+)-Betulonic acid

HRID 2393066Notes

Reaction equation

HRID 2393066 reaction equation
[CH3:1][C:2]([C@H:4]1[C@@H:8]2[C@@H:9]3[C@@:22]([CH3:25])([CH2:23][CH2:24][C@@:7]2([CH2:31][OH:32])[CH2:6][CH2:5]1)[C@@:21]1([CH3:26])[C@@H:12]([C@:13]2([CH3:30])[C@@H:18]([CH2:19][CH2:20]1)[C:17]([CH3:28])([CH3:27])[C@@H:16]([OH:29])[CH2:15][CH2:14]2)[CH2:11][CH2:10]3)=[CH2:3].CC(C)=[O:35].OS(O)(=O)=O.O=[Cr](=O)=O>CC(C)=O>[CH3:3][C:2]([C@H:4]1[C@@H:8]2[C@@H:9]3[C@@:22]([CH3:25])([CH2:23][CH2:24][C@@:7]2([C:31]([OH:35])=[O:32])[CH2:6][CH2:5]1)[C@@:21]1([CH3:26])[C@@H:12]([C@:13]2([CH3:30])[C@@H:18]([CH2:19][CH2:20]1)[C:17]([CH3:28])([CH3:27])[C:16](=[O:29])[CH2:15][CH2:14]2)[CH2:11][CH2:10]3)=[CH2:1]

Participants

4

Reactant 2

HCID 72326BetulinHCID 131709961Jones' reagent

Product 1

HCID 122844(+)-Betulonic acid

Reagents, catalysts & solvents 1

HCID 180AcetoneSolvent

Conditions

Temperature
0 °C

Procedure

To a solution of betulin (1, 1.0 g, 2.26 mmol) in acetone (50 mL), cooled to 0° C., freshly prepared Jones' reagent was added dropwise. The resulting mixture was stirred for about 1.5 hours at 0° C., quenched with methanol (25 mL), stirred for an additional 5 minutes, then water (40 mL) was added. The acetone was removed under vacuum and the aqueous residue was extracted two times with 40 mL of ethyl acetate (EtOAc). The ethyl acetate layer was separated from the aqueous layer, then the ethyl acetate layer was washed first with water (20 mL) and then with brine (15 mL). The ethyl acetate layer was dried over magnesium sulfate (MgSO4), then filtered, and finally the ethyl acetate was removed under vacuum. The residue was column chromatographed over silica gel (60-200 mesh) using petroleum ether/EtOAc (4:1 volume ratio) to yield 770 mg of betulonic acid, having a melting point (mp) of 247°-249° C. (literature mp 246°-2470° C.). The reaction provided a 75% yield of betulonic acid.

Workup

  1. customquenched with methanol (25 mL)
  2. stirringstirred for an additional 5 minutes
  3. additionwater (40 mL) was added
  4. customThe acetone was removed under vacuum
  5. extractionthe aqueous residue was extracted two times with 40 mL of ethyl acetate (EtOAc)
  6. customThe ethyl acetate layer was separated from the aqueous layer
  7. washthe ethyl acetate layer was washed first with water (20 mL)
  8. dry with materialThe ethyl acetate layer was dried over magnesium sulfate (MgSO4)
  9. filtrationfiltered
  10. customfinally the ethyl acetate was removed under vacuum
  11. customchromatographed over silica gel (60-200 mesh)

Sources & evidence

ORD record
ord-710e1e944b6848faaf9356193f440107
Source dataset
uspto-grants-1998_09
Patent number
US05804575

Reaction notes

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