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

HRID 2187274Notes

Reaction equation

HRID 2187274 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-86269ca5c79f4ba2babce669fefe7df9
Source dataset
uspto-grants-2002_06
Patent number
US06407086B2

Reaction notes

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