Perchloric Acid → 21-Acetoxy-6alpha-chloro-9,11beta-epoxy-16alpha-methyl-9beta-pregna-1,4-diene-3,20-dione

HRID 1577862Notes

Reaction equation

HRID 1577862 reaction equation
[C:1]([O:4][CH2:5][C:6](=[O:29])[C@@H:7]1[C@:24]2([CH3:25])[C@H:10]([C@H:11]3[C:21](=[CH:22][CH2:23]2)[C@:19]2([CH3:20])[C:14](=[CH:15][C:16](=[O:26])[CH:17]=[CH:18]2)[C@@H:13]([Cl:27])[CH2:12]3)[CH2:9][C@H:8]1[CH3:28])(=[O:3])[CH3:2].BrN1C(=[O:36])CCC1=O.Cl(O)(=O)(=O)=O>O1CCOCC1>[C:1]([O:4][CH2:5][C:6](=[O:29])[C@@H:7]1[C@:24]2([CH3:25])[C@H:10]([C@H:11]3[C@:21]4([O:36][C@H:22]4[CH2:23]2)[C@:19]2([CH3:20])[C:14](=[CH:15][C:16](=[O:26])[CH:17]=[CH:18]2)[C@@H:13]([Cl:27])[CH2:12]3)[CH2:9][C@H:8]1[CH3:28])(=[O:3])[CH3:2]

Participants

5

Reactant 3

HCID 24247Perchloric AcidHCID 67184N-bromobutanimideHCID 2281743021-Acetoxy-6alpha-chloro-16alpha-methyl-1,4,9(11)-pregnatriene-3,20-dione

Product 1

HCID 8673801421-Acetoxy-6alpha-chloro-9,11beta-epoxy-16alpha-methyl-9beta-pregna-1,4-diene-3,20-dioneYield 41.7%

Reagents, catalysts & solvents 1

HCID 312751,4-DioxaneSolvent

Procedure

A solution of 12.0 g of 21-acetoxy-6α-chloro-16α-methyl-1,4,9(11)-pregnatriene-3,20-dione in 120 ml of dioxane is stirred at room temperature after adding 11.1 g of N-bromosuccinimide and 60 ml of 10% perchloric acid and, after 60 minutes, poured into ice water. The thus-precipitated product is filtered off, washed with water, dried in the air, and dissovled in 215 ml of ethanol. After adding 29 g of potassium acetate, the solution is heated for 8 hours to 60° C. under argon. Then the mixture is concentrated to a volume of 60 ml under vacuum, and stirred into ice water. The precipitated product is isolated and chromatographed on silica gel. With 8-9% acetone-hexane, after recrystallization from acetone-diisopropyl ether, 5.2 g of 21-acetoxy-6α-chloro-9,11β-epoxy-16α-methyl-9β-pregna-1,4-diene-3,20-dione is obtained, m.p. 189° C. [α]D25 =+57° (chloroform).

Workup

  1. filtrationThe thus-precipitated product is filtered off
  2. washwashed with water
  3. customdried in the air
  4. additionAfter adding 29 g of potassium acetate
  5. temperaturethe solution is heated for 8 hours to 60° C. under argon
  6. concentrationThen the mixture is concentrated to a volume of 60 ml under vacuum
  7. customThe precipitated product is isolated
  8. customchromatographed on silica gel
  9. customWith 8-9% acetone-hexane, after recrystallization from acetone-diisopropyl ether

Sources & evidence

ORD record
ord-6076137a15894860bb94e0de0eb4cc8b
Source dataset
uspto-grants-1981_09
Patent number
US04289763

Reaction notes

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