Hydrochloric Acid → 24-Oxocholesterol acetate

HRID 3090

Reaction equation

HRID 3090 reaction equation
[Mg].Br[CH:3]([CH3:5])[CH3:4].C([Mg]Br)(C)C.[C:11]([O:14][C@H:15]1[CH2:38][CH2:37][C@@:36]2([CH3:39])[C:17](=[CH:18][CH2:19][C@@H:20]3[C@@H:35]2[CH2:34][CH2:33][C@@:32]2([CH3:40])[C@H:21]3[CH2:22][CH2:23][C@@H:24]2[C@H:25]([CH3:31])[CH2:26][CH2:27][C:28](Cl)=[O:29])[CH2:16]1)(=[O:13])[CH3:12].Cl>CCOCC.C1C=CC=CC=1.[Br-].[Cd+2].[Br-]>[C:11]([O:14][C@H:15]1[CH2:38][CH2:37][C@@:36]2([CH3:39])[C:17](=[CH:18][CH2:19][C@@H:20]3[C@@H:35]2[CH2:34][CH2:33][C@@:32]2([CH3:40])[C@H:21]3[CH2:22][CH2:23][C@@H:24]2[C@H:25]([CH3:31])[CH2:26][CH2:27][C:28](=[O:29])[CH:3]([CH3:5])[CH3:4])[CH2:16]1)(=[O:13])[CH3:12]

Participants

9

Reactant 5

HCID 313Hydrochloric AcidHCID 63582-BromopropaneHCID 5462224MagnesiumHCID 129533373beta-Acetoxy-5-cholenic acid chlorideHCID 178418365HCID 178418365, compound

Product 1

HCID 1097227324-Oxocholesterol acetateYield 70%

Reagents, catalysts & solvents 3

HCID 9816930Cadmium bromideCatalystHCID 241BenzeneSolvent2×HCID 3283Diethyl EtherSolvent

Procedure

To a mixture of magnesium (24 g, 1.00 mole) in dry ether (500 ml) was added dropwise 2-bromopropane (60 ml, 639 mmole) while stirring. After the addition was completed, the reaction mixture was stirred for thirty minutes. The ethereal solution was transferred to another flask. Then to the resulting isopropyl-magnesium bromide solution was added portionwise cadmium bromide (75 g, 276 mmole) at room temperature. The resulting dark solution was refluxed gently for one hour, followed by the addition of dry benzene (200 ml), then most of the ether was removed. To this mixture, 3β-acetoxy-5-cholenic acid chloride 331 (50 g, 115 mmole) in dry benzene (300 ml) was added dropwise. The reaction mixture was stirred at room temperature for one hour and then poured slowly into a crushed ice and 10% hydrochloric acid mixture. The organic layer was separated. The aqueous layer was extracted with ether (3×300 ml). The combined ethereal solution was washed with 10% HCl, washed with water, dried (MgSO4), filtered, and concentrated in vacuo to give crude product, 3β-acetoxy-24-oxo-5-cholestene 332 (35.6 g, 70% yield), which was used for the next reaction without further purification. 1H NMR (400 MHz, CDCl3) δ: 0.69 (3H, s, 18-CH3), 0.95 (3H, d, 21-CH3), 1.04 (3H, s, 19-CH3), 1.25 (6H, 2d, 26-CH3, 27-CH3), 2.04 (3H, s, --OCOCH3), 4.61 (1H, m, 3α-H), 5.38 (1H, m, 6-H).

Workup

  1. additionAfter the addition
  2. stirringthe reaction mixture was stirred for thirty minutes
  3. customThe ethereal solution was transferred to another flask
  4. temperatureThe resulting dark solution was refluxed gently for one hour
  5. custommost of the ether was removed
  6. stirringThe reaction mixture was stirred at room temperature for one hour
  7. customThe organic layer was separated
  8. extractionThe aqueous layer was extracted with ether (3×300 ml)
  9. washThe combined ethereal solution was washed with 10% HCl
  10. washwashed with water
  11. dry with materialdried (MgSO4)
  12. filtrationfiltered
  13. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-b098fde08ae9480bb834d7a3afe28656
Source dataset
uspto-grants-1998_03
Patent number
US05733899

Linked notes

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