1,3-Dibromo-5,5-dimethylhydantoin → 6020-61-7

HRID 2183424Notes

Reaction equation

HRID 2183424 reaction equation
[CH3:1][CH2:2][C@@H:3]([CH:31]([CH3:33])[CH3:32])[CH2:4][CH2:5][C@H:6]([C@@H:8]1[C@@:12]2([CH3:30])[CH2:13][CH2:14][C@@H:15]3[C@@:20]4([CH3:29])[CH2:21][CH2:22][C@H:23]([O:25][C:26]([CH3:28])=[O:27])[CH2:24][C:19]4=[CH:18][CH2:17][C@H:16]3[C@@H:11]2[CH2:10][CH2:9]1)[CH3:7].C([O-])(O)=O.[Na+].CC1(C)N(Br)C(=O)N(Br)C1=O.[F-].C([N+](CCCC)(CCCC)CCCC)CCC.CC1C=C(C)N=C(C)C=1>CCCCCCC.[Br-].C([N+](CCCC)(CCCC)CCCC)CCC.CCOCC.O>[CH3:1][CH2:2][C@@H:3]([CH:31]([CH3:32])[CH3:33])[CH2:4][CH2:5][C@H:6]([C@@H:8]1[C@@:12]2([CH3:30])[CH2:13][CH2:14][C@@H:15]3[C@@:20]4([CH3:29])[CH2:21][CH2:22][C@H:23]([O:25][C:26]([CH3:28])=[O:27])[CH2:24][C:19]4=[CH:18][CH:17]=[C:16]3[C@@H:11]2[CH2:10][CH2:9]1)[CH3:7]

Participants

10

Reactant 5

HCID 64791,3-Dibromo-5,5-dimethylhydantoinHCID 79532,4,6-TrimethylpyridineHCID 516892Sodium BicarbonateHCID 2724141Tetrabutylammonium FluorideHCID 5354503beta-Sitosterol acetate

Product 1

HCID 117194496020-61-7Yield 75%

Reagents, catalysts & solvents 4

HCID 74236Tetrabutylammonium BromideCatalystHCID 962WaterSolventHCID 3283Diethyl EtherSolventHCID 8900HeptaneSolvent

Procedure

A suspension of sitosterol acetate (5) (10 g, 21.89 mmol), anhydrous NaHCO3 (9.19 G, 109.45 mmol) and dibromantin in heptane (250 mL) was refluxed for 2 h under argon atmosphere. The reaction mixture was cooled to room temperature and filtered, and then the solvent was removed in vacuo. To the reaction flask, THF (50 mL) was added followed by tetrabutylammonium bromide (0.65 g, 2.02 mmol). The solution was stirred at room temperature for 30 minutes under argon atmosphere. To this reaction mixture tetrabutylammonium fluoride (112 mL, 1 M solution in THF) was added and followed by s-collidine (5 mL). Then the reaction mixture was stirred at room temperature for 20 h. The reaction mixture was diluted with ether (1.5 L), then water (600 mL) was added. The crude reaction mixture was transferred to a separating funnel, the water layer was removed, the organic layer was washed with water (500 mL), 1 N HC1 (2×600 mL), water (600 mL), then brine (500 mL). The organic layer was dried (MgSO4) and concentrated in vacuo to afford a dark brown viscous liquid. The crude reaction mixture was purified by column chromatography (silica gel, ethyl acetate-hexane 1:9 mixture as eluent) to afford 6.5 g, (75%) 7-dehydrositosterol acetate (6) as a pale brown viscous liquid.

Workup

  1. temperaturewas refluxed for 2 h under argon atmosphere
  2. filtrationfiltered
  3. customthe solvent was removed in vacuo
  4. additionTo the reaction flask, THF (50 mL) was added
  5. stirringThen the reaction mixture was stirred at room temperature for 20 h
  6. customThe crude reaction mixture
  7. customwas transferred to a separating funnel
  8. customthe water layer was removed
  9. washthe organic layer was washed with water (500 mL), 1 N HC1 (2×600 mL), water (600 mL)
  10. dry with materialThe organic layer was dried (MgSO4)
  11. concentrationconcentrated in vacuo
  12. customto afford a dark brown viscous liquid
  13. customThe crude reaction mixture
  14. customwas purified by column chromatography (silica gel, ethyl acetate-hexane 1:9 mixture as eluent)

Sources & evidence

ORD record
ord-10235e7241d74ca58da290247129bd66
Source dataset
uspto-grants-2005_05
Patent number
US06900191B1

Reaction notes

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