Water → 20-(5,5-Dimethyl-1,3-dioxan-2-yl)pregna-1,4,6-trien-3-one

HRID 1196312Notes

Reaction equation

HRID 1196312 reaction equation
[CH3:1][C:2]1([CH3:31])[CH2:7][O:6][CH:5]([CH:8]([C@@H:10]2[C@:27]3([CH3:28])[C@H:13]([C@H:14]4[C@H:24]([CH2:25][CH2:26]3)[C@:22]3([CH3:23])[C:17](=[CH:18][C:19](=[O:29])[CH:20]=[CH:21]3)[CH2:16][C@H:15]4O)[CH2:12][CH2:11]2)[CH3:9])[O:4][CH2:3]1.C1(C)C=CC(S(O)(=O)=O)=CC=1.O.C(OCC)(=O)C.CCCCCC>C1C=CC=CC=1>[CH3:31][C:2]1([CH3:1])[CH2:3][O:4][CH:5]([CH:8]([C@@H:10]2[C@:27]3([CH3:28])[C@H:13]([C@H:14]4[C@H:24]([CH2:25][CH2:26]3)[C@:22]3([CH3:23])[C:17](=[CH:18][C:19](=[O:29])[CH:20]=[CH:21]3)[CH:16]=[CH:15]4)[CH2:12][CH2:11]2)[CH3:9])[O:6][CH2:7]1

Participants

6

Reactant 4

HCID 962WaterHCID 6101p-Toluenesulfonic acidHCID 21226206Ethyl acetate hexaneHCID 2284393020-(5,5-Dimethyl-1,3-dioxan-2-yl)-7alpha-hydroxypregna-1,4-dien-3one

Product 1

HCID 2284393220-(5,5-Dimethyl-1,3-dioxan-2-yl)pregna-1,4,6-trien-3-oneYield 90%

Reagents, catalysts & solvents 1

HCID 241BenzeneSolvent

Procedure

To a solution of 3.00 g (6.98 mmoles) of 20-(5,5-dimethyl-1,3-dioxan-2-yl)-7α-hydroxypregna-1,4-dien-3-one in 200 ml of benzene was added 50 mg of p-toluenesulfonic acid and the mixture was refluxed for 5 hours, with the byproduct water being constantly removed from the reaction system by means of a Dean-Stark trap. The reaction mixture thus obtained was cooled to room temperature and washed with aqueous sodium hydrogen carbonate solution. The aqueous layer was extracted with ether and the extract was combined with the organic layer. This mixture was washed with aqueous sodium chloride solution and dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. Finally the residue was purified by silica gel chromatography (eluent: ethyl acetate-hexane =1:10, v/v) to recover 2.58 g of 20-(5,5-dimethyl-1,3-dioxan-2-yl)pregna-1,4,6-trien-3-one (yield: 90%). The 1H-NMR spectrum of this product was in agreement with that of the 20-(5,5-dimethyl-1,3-dioxan-2-yl)pregna-1,4,6-trien-3-one obtained in Example 3.

Workup

  1. customconstantly removed from the reaction system by means of a Dean-Stark trap
  2. customThe reaction mixture thus obtained
  3. washwashed with aqueous sodium hydrogen carbonate solution
  4. extractionThe aqueous layer was extracted with ether
  5. washThis mixture was washed with aqueous sodium chloride solution
  6. dry with materialdried over magnesium sulfate
  7. distillationthe solvent was distilled off under reduced pressure
  8. customFinally the residue was purified by silica gel chromatography (eluent

Sources & evidence

ORD record
ord-5bccbcc13aa7416f993ef0149b736694
Source dataset
uspto-grants-1992_05
Patent number
US05112998

Reaction notes

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