Sodium borohydride → 1alpha,3beta-bis(tert-butyldimethylsilyloxy)-20(R)-hydroxypregna-5,7,16-triene

HRID 2268307Notes

Reaction equation

HRID 2268307 reaction equation
[Si:1]([O:8][C@@H:9]1[C@@:28]2([CH3:29])[C:13](=[CH:14][CH:15]=[C:16]3[C@@H:27]2[CH2:26][CH2:25][C@@:24]2([CH3:30])[C@H:17]3[CH2:18][CH:19]=[C:20]2[C:21](=[O:23])[CH3:22])[CH2:12][C@@H:11]([O:31][Si:32]([C:35]([CH3:38])([CH3:37])[CH3:36])([CH3:34])[CH3:33])[CH2:10]1)([C:4]([CH3:7])([CH3:6])[CH3:5])([CH3:3])[CH3:2].O.O.O.O.O.O.O.[Cl-].[Ce+3].[Cl-].[Cl-].[BH4-].[Na+]>CO.O1CCCC1>[Si:1]([O:8][C@@H:9]1[C@@:28]2([CH3:29])[C:13](=[CH:14][CH:15]=[C:16]3[C@@H:27]2[CH2:26][CH2:25][C@@:24]2([CH3:30])[C@H:17]3[CH2:18][CH:19]=[C:20]2[C@H:21]([OH:23])[CH3:22])[CH2:12][C@@H:11]([O:31][Si:32]([C:35]([CH3:36])([CH3:38])[CH3:37])([CH3:33])[CH3:34])[CH2:10]1)([C:4]([CH3:7])([CH3:6])[CH3:5])([CH3:3])[CH3:2].[Si:1]([O:8][C@@H:9]1[C@@:28]2([CH3:29])[C:13](=[CH:14][CH:15]=[C:16]3[C@@H:27]2[CH2:26][CH2:25][C@@:24]2([CH3:30])[C@H:17]3[CH2:18][CH:19]=[C:20]2[C@@H:21]([OH:23])[CH3:22])[CH2:12][C@@H:11]([O:31][Si:32]([C:35]([CH3:36])([CH3:38])[CH3:37])([CH3:33])[CH3:34])[CH2:10]1)([C:4]([CH3:7])([CH3:6])[CH3:5])([CH3:3])[CH3:2]

Participants

7

Reactant 3

HCID 4311764Sodium borohydrideHCID 120200821alpha,3beta-Bis(tert-butyldimethylsilyloxy)-20-oxopregna-5,7,16-trieneHCID 21585214Cerium trichloride heptahydrate

Product 2

HCID 120200781alpha,3beta-bis(tert-butyldimethylsilyloxy)-20(S)-hydroxypregna-5,7,16-trieneYield 18%HCID 120200831alpha,3beta-bis(tert-butyldimethylsilyloxy)-20(R)-hydroxypregna-5,7,16-trieneYield 73%

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 8028TetrahydrofuranSolvent

Procedure

To a solution of 1α,3β-bis(tert-butyldimethylsilyloxy)-20-oxopregna-5,7,16-triene (93 mg, 0.167 mmol) and cerium (III) chloride heptahydrate (93 mg, 0.251 mmol) in methanol (1.5 ml) and tetrahydrofuran (6 ml) cooled at 0° C. was gradually added sodium borohydride (32 mg, 0.835 mmol). The reaction solution was stirred at room temperature for one hour, then concentrated under reduced pressure and the residue was taken into water and extracted with ethyl acetate. The organic layer was washed with brine and then dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. The resulting residue was purified by preparative thin layer chromatography (0.5 mm×2, hexane:ethyl acetate=10:1, developed three times) to give the title compound as a colorless solid (68.2 mg, 73%) and 1α,3β-bis(tert-butyldimethylsilyloxy)-20(S)-hydroxypregna-5,7,16-triene (17.0 mg, 18%).

Workup

  1. concentrationconcentrated under reduced pressure
  2. extractionextracted with ethyl acetate
  3. washThe organic layer was washed with brine
  4. dry with materialdried over magnesium sulfate
  5. distillationthe solvent was distilled off under reduced pressure
  6. customThe resulting residue was purified by preparative thin layer chromatography (0.5 mm×2, hexane:ethyl acetate=10:1, developed three times)

Sources & evidence

ORD record
ord-e795712bc1074353961d443e1f132f51
Source dataset
uspto-grants-2001_12
Patent number
US06326503B1

Reaction notes

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