1,3-Dibromo-5,5-dimethylhydantoin → 3beta,24-Bis(tert-butyldimethylsilyloxy)-4,4-dimethylchola-5,7-diene

HRID 1816487Notes

Reaction equation

HRID 1816487 reaction equation
[Si:1]([O:8][C@H:9]1[CH2:38][CH2:37][C@@:36]2([CH3:39])[C:11](=[CH:12][CH2:13][C@@H:14]3[C@@H:35]2[CH2:34][CH2:33][C@@:32]2([CH3:40])[C@H:15]3[CH2:16][CH2:17][C@@H:18]2[C@H:19]([CH3:31])[CH2:20][CH2:21][CH2:22][O:23][Si:24]([C:27]([CH3:30])([CH3:29])[CH3:28])([CH3:26])[CH3:25])[C:10]1([CH3:42])[CH3:41])([C:4]([CH3:7])([CH3:6])[CH3:5])([CH3:3])[CH3:2].BrN1C(C)(C)C(=O)N(Br)C1=O>CCCCCC.C1C=CC=CC=1>[Si:1]([O:8][C@H:9]1[CH2:38][CH2:37][C@@:36]2([CH3:39])[C:11](=[CH:12][CH:13]=[C:14]3[C@@H:35]2[CH2:34][CH2:33][C@@:32]2([CH3:40])[C@H:15]3[CH2:16][CH2:17][C@@H:18]2[C@H:19]([CH3:31])[CH2:20][CH2:21][CH2:22][O:23][Si:24]([C:27]([CH3:28])([CH3:29])[CH3:30])([CH3:26])[CH3:25])[C:10]1([CH3:41])[CH3:42])([C:4]([CH3:5])([CH3:6])[CH3:7])([CH3:3])[CH3:2]

Participants

5

Reactant 2

HCID 64791,3-Dibromo-5,5-dimethylhydantoinHCID 155430903beta,24-Bis(tert-butyldimethylsilyloxy)4,4-dimethylchol-5-ene

Product 1

HCID 694129983beta,24-Bis(tert-butyldimethylsilyloxy)-4,4-dimethylchola-5,7-dieneYield 88.9%

Reagents, catalysts & solvents 2

HCID 241BenzeneSolventHCID 8058HexaneSolvent

Procedure

3β,24-Bis(tert-butyldimethylsilyloxy)-4,4-dimethylchol-5-ene (44 g) is dissolved in a warm mixture of hexane (2 l) and benzene (540 ml). 1,3-Dibromo-5,5-dimethylhydantoin (15.32 g) is added and the mixture is refluxed for 20 min and then cooled rapidly to room temperature, and the insoluble material is removed by filtration. The filtrate is concentrated under reduced pressure and o-xylene (2 l) and quinaldine (84 ml) is added. The mixture is refluxed for 1 hour. After aqueous work-up and trituration with methanol, 3β,24-bis(tert-butyldimethylsilyloxy)-4,4-dimethylchola-5,7-diene (39 g) is isolated. Melting point: 98-106° C. 1H-NMR (CDCl3, 400 MHz): δ=5.9 (1H, m); 5.54 (1H, m); 3.58 (2H, m); 3.35 (1H, m); 0.91 (18H, s); 0.05 (12H, m).

Workup

  1. temperaturethe mixture is refluxed for 20 min
  2. customthe insoluble material is removed by filtration
  3. concentrationThe filtrate is concentrated under reduced pressure and o-xylene (2 l) and quinaldine (84 ml)
  4. additionis added
  5. temperatureThe mixture is refluxed for 1 hour

Sources & evidence

ORD record
ord-bd95cea129e747cf89c431582940f4d1
Source dataset
uspto-grants-2005_04
Patent number
US06884796B2

Reaction notes

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