Hydrogen Bromide → 21-Bromo-3beta-hydroxypregna-5,16-dien-20-one

HRID 1488935Notes

Reaction equation

HRID 1488935 reaction equation
[CH3:1][C:2]([C:4]1[C@@:8]2([CH3:23])[CH2:9][CH2:10][C@@H:11]3[C@@:16]4([CH3:22])[CH2:17][CH2:18][C@H:19]([OH:21])[CH2:20][C:15]4=[CH:14][CH2:13][C@H:12]3[C@@H:7]2[CH2:6][CH:5]=1)=[O:3].[Br:24]C1(Br)C(=O)NC(=O)NC1=O.Br>O1CCCC1.C(Cl)Cl>[Br:24][CH2:1][C:2](=[O:3])[C:4]1[C@:8]2([CH3:23])[C@H:7]([C@H:12]3[C@H:11]([CH2:10][CH2:9]2)[C@:16]2([CH3:22])[C:15]([CH2:20][C@@H:19]([OH:21])[CH2:18][CH2:17]2)=[CH:14][CH2:13]3)[CH2:6][CH:5]=1

Participants

6

Reactant 3

HCID 260Hydrogen BromideHCID 9287116-DehydropregnenoloneHCID 948775,5-Dibromobarbituric acid

Product 1

HCID 1064426921-Bromo-3beta-hydroxypregna-5,16-dien-20-oneYield 104.4%

Reagents, catalysts & solvents 2

HCID 6344DichloromethaneSolventHCID 8028TetrahydrofuranSolvent

Procedure

Dissolve 16-dehydropregnenolone (5.00 g, 15.90 mmol) and 5,5-dibromobarbituric acid (4.55 g, 15.90 mmol) in tetrahydrofuran (60 mL). Add concentrated aqueous hydrogen bromide (100 μL of a 48% solution) to the stirring solution and heat the reaction at reflux for 1 hour. Cool slightly and then concentrate under vacuum to produce a brown oily foam. Dissolve the residue in methylene chloride (350 mL), rinse with 50% saturated sodium bicarbonate (2×200 mL), brine (125 mL), dry over anhydrous magnesium sulfate, filter and concentrate under vacuum to provide 21-bromo-3β-hydroxypregna-5,16-dien-20-one (6.53 g) as an orange-brown solid, slightly contaminated with starting material.

Workup

  1. temperatureheat
  2. customthe reaction
  3. temperatureat reflux for 1 hour
  4. temperatureCool slightly
  5. concentrationconcentrate under vacuum
  6. customto produce a brown oily foam
  7. washrinse with 50% saturated sodium bicarbonate (2×200 mL), brine (125 mL)
  8. dry with materialdry over anhydrous magnesium sulfate
  9. filtrationfilter
  10. concentrationconcentrate under vacuum

Sources & evidence

ORD record
ord-f2f1fb21b46f4ac8904c3542b7de7a3a
Source dataset
uspto-grants-1997_10
Patent number
US05677293

Reaction notes

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