Benzoic Acid → 3alpha-Benzoyloxy-5alpha-pregnan-20-one

HRID 232802

Reaction equation

HRID 232802 reaction equation
[OH:1][C@H:2]1[CH2:21][CH2:20][C@@:19]2([CH3:22])[C@@H:4]([CH2:5][CH2:6][C@@H:7]3[C@@H:18]2[CH2:17][CH2:16][C@@:15]2([CH3:23])[C@H:8]3[CH2:9][CH2:10][C@@H:11]2[C:12](=[O:14])[CH3:13])[CH2:3]1.C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.[C:43](O)(=[O:50])[C:44]1[CH:49]=[CH:48][CH:47]=[CH:46][CH:45]=1>O1CCCC1>[C:43]([O:1][C@@H:2]1[CH2:21][CH2:20][C@@:19]2([CH3:22])[C@@H:4]([CH2:5][CH2:6][C@@H:7]3[C@@H:18]2[CH2:17][CH2:16][C@@:15]2([CH3:23])[C@H:8]3[CH2:9][CH2:10][C@@H:11]2[C:12](=[O:14])[CH3:13])[CH2:3]1)(=[O:50])[C:44]1[CH:49]=[CH:48][CH:47]=[CH:46][CH:45]=1

Participants

5

Reactant 3

HCID 243Benzoic AcidHCID 11776TriphenylphosphineHCID 92787Isopregnanolone

Product 1

HCID 543102073alpha-Benzoyloxy-5alpha-pregnan-20-oneYield 92.8%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

A mixture of 3β-hydroxy-5α-pregnan-20-one (285 mg, 318.5 g/m, 0.89 mmol), triphenylphosphine (258 mg, 262.3 g/m, 0.94 mmol), and benzoic acid (120 mg, 122.2 g/m, 0.98 mmol) was dissolved in 25 mL of tetrahydrofuran (freshly distilled). To this stirred reaction mixture at room temperature was added a solution of diisopropylazidodicarboxylate (DIAD) (0.194 mL, 1.027 g/ml, 202.2 g/m, 0.98 mmol) in 5 mL of tetrahydrofuran dropwise over a period of 5 minutes. The reaction was followed by thin layer chromatography (TLC) as the starting material was consumed. After two hours, the reaction mixture was concentrated under reduced pressure and filtered through a bed of silica gel (10 g) with a mixture of hexane/ethyl acetate (9:1). Fractions corresponding to the title compound were concentrated to give 349 mg of 3α-benzoyloxy-5α-pregnan-20-one (92% yield) as a white solid.

Workup

  1. distillationfreshly distilled)
  2. customTo this stirred reaction mixture at room temperature
  3. customwas consumed
  4. concentrationthe reaction mixture was concentrated under reduced pressure
  5. filtrationfiltered through a bed of silica gel (10 g) with a mixture of hexane/ethyl acetate (9:1)
  6. concentrationFractions corresponding to the title compound were concentrated

Sources & evidence

ORD record
ord-e08fb4dab4a244bcb5673f0b40e9b1f6
Source dataset
uspto-grants-1997_01
Patent number
US05591733

Linked notes

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