Acetone → (+)-Betulonic acid

HRID 869824Notes

Reaction equation

HRID 869824 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]>>[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

3

Reactant 2

HCID 180AcetoneHCID 72326Betulin

Product 1

HCID 122844(+)-Betulonic acidYield 67%

Conditions

Temperature
0 °C

Procedure

To a solution of betulin 1 (1 g, 2.26 mmol) in acetone (50 ml), cooled at 0° C., freshly prepared Jone's reagent was added dropwise. The resulting mixture was stirred for about 1.5 h 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 with ethyl acetate (2×40 ml) and washed with water (30 ml) and brine (30 ml). Dried with Na2SO4, filtered, and concentrated under reduced pressure. The residue solid was submitted to FCC with petroleum ether 40-60° C./ethyl acetate (4:1) and afforded compound 11 (685 mg, 67%): IR (film) υmax 3070, 1703, 1686, 1642 cm−1; 1H NMR (CDCl3, 300 MHz) δ 4.77 (brs, 1H, H-29a), 4.64 (brs, 1H, H-29b), 3.04 (dt, J=10.7 Hz, J=4.3 Hz, 1H, H-19), 1.72 (s, 3H, H-30), 1.09 (s, 3H), 1.04 (s, 3H), 1.02 (s, 3H), 0.99 (s, 3H), 0.95 (s, 3H). 13C NMR (CDCl3, 75 MHz) δ 218.2 (C3), 182.2 (C28), 150.3 (C20), 109.7 (C29). EI-MS m/z (% rel. intensity): 454 (19) M+, 408 (24), 393 (20), 248 (85), 189 (100), 175 (62), 133 (55), 119 (76), 105 (69), 79 (52).

Workup

  1. additionfreshly prepared Jone's reagent was added dropwise
  2. customquenched with methanol (25 ml)
  3. stirringstirred for an additional 5 minutes
  4. additionwater (40 ml) was added
  5. customThe acetone was removed under vacuum
  6. extractionthe aqueous residue was extracted with ethyl acetate (2×40 ml)
  7. washwashed with water (30 ml) and brine (30 ml)
  8. dry with materialDried with Na2SO4
  9. filtrationfiltered
  10. concentrationconcentrated under reduced pressure
  11. customwas submitted to FCC with petroleum ether 40-60° C./ethyl acetate (4:1)

Sources & evidence

ORD record
ord-d9646e3215ad40ee85a1a7d7fedb4452
Source dataset
uspto-grants-2015_03
Patent number
US08969395B2

Reaction notes

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