Hydrogen Bromide → 2beta-Bromo-3alpha-hydroxy-5alpha-pregnan-20-one

HRID 1606481Notes

Reaction equation

HRID 1606481 reaction equation
[O:1]1[C@H:3]2[CH2:4][C@H:5]3[C@:20]([CH3:22])([CH2:21][C@@H:2]12)[C@@H:19]1[C@H:8]([C@H:9]2[C@:16]([CH3:23])([CH2:17][CH2:18]1)[C@@H:12]([C:13](=[O:15])[CH3:14])[CH2:11][CH2:10]2)[CH2:7][CH2:6]3.[BrH:24]>C(Cl)(Cl)Cl>[Br:24][C@H:2]1[CH2:21][C@@:20]2([CH3:22])[C@@H:5]([CH2:6][CH2:7][C@@H:8]3[C@@H:19]2[CH2:18][CH2:17][C@@:16]2([CH3:23])[C@H:9]3[CH2:10][CH2:11][C@@H:12]2[C:13](=[O:15])[CH3:14])[CH2:4][C@@H:3]1[OH:1]

Participants

4

Reactant 2

HCID 260Hydrogen BromideHCID 543466312alpha,3alpha-Epoxy-5alpha-pregnan-20-one

Product 1

HCID 572036952beta-Bromo-3alpha-hydroxy-5alpha-pregnan-20-one

Reagents, catalysts & solvents 1

HCID 6212ChloroformSolvent2×

Procedure

2α, 3α-Epoxy-5α-pregnan-20-one (356 mg.) was dissolved in chloroform (20 ml.) and hydrobromic acid (48%, 7 ml.) was added. The mixture was stirred at room temperature for 30 minutes and then poured into chloroform (100 ml.). The organic solution was washed with dilute sodium bicarbonate solution and with water, then dried over sodium sulphate and evaporated to give a crystalline residue which was recrystallised from ethyl acetate containing some ether to give title compound (144 mg.) as colourless needles m.p. 171°-175°, [α]D + 117°.

Workup

  1. washThe organic solution was washed with dilute sodium bicarbonate solution and with water
  2. dry with materialdried over sodium sulphate
  3. customevaporated
  4. customto give a crystalline residue which
  5. customwas recrystallised from ethyl acetate containing some ether

Sources & evidence

ORD record
ord-01fc4e454cbd4d23a019161f284c0385
Source dataset
uspto-grants-1976_04
Patent number
US03953429

Reaction notes

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