Hydrochloric Acid → 5alpha-Pregn-2-en-20-one

HRID 232794Notes

Reaction equation

HRID 232794 reaction equation
C1(C)C=CC(S(O[C@@H:11]2[CH2:30][CH2:29][C@@:28]3([CH3:31])[C@@H:13]([CH2:14][CH2:15][C@@H:16]4[C@@H:27]3[CH2:26][CH2:25][C@@:24]3([CH3:32])[C@H:17]4[CH2:18][CH2:19][C@@H:20]3[C:21](=[O:23])[CH3:22])[CH2:12]2)(=O)=O)=CC=1.Cl>N1C(C)=CC(C)=CC=1C>[CH3:22][C:21](=[O:23])[C@@H:20]1[C@:24]2([CH3:32])[C@H:17]([C@H:16]3[C@H:27]([CH2:26][CH2:25]2)[C@:28]2([CH3:31])[C@H:13]([CH2:12][CH:11]=[CH:30][CH2:29]2)[CH2:14][CH2:15]3)[CH2:18][CH2:19]1

Participants

4

Reactant 2

HCID 313Hydrochloric AcidHCID 538852373alpha-Toluene-p-sulphonyloxy-5alpha-pregnan-20-one

Product 1

HCID 2468835alpha-Pregn-2-en-20-oneYield 97%

Reagents, catalysts & solvents 1

HCID 79532,4,6-TrimethylpyridineSolvent

Procedure

The crude product 3α-toluene-p-sulphonyloxy-5α-pregnan-20-one in 30 mL of collidine was refluxed for 1.0 h. The solution was allowed to cool and then poured into cold dilute hydrochloric acid (200 mL) and extracted three times with CH2Cl2 (100 mL portions). The combined organic phase was dried over magnesium sulfate and concentrated. Flash chromatography on a silica gel bed (100 g) and elution with hexane/ethyl acetate (80:20) gave 4.65 g (97% yield for the two steps) of 5α-pregn-2-ene-20-one.

Workup

  1. temperatureto cool
  2. extractionextracted three times with CH2Cl2 (100 mL portions)
  3. dry with materialThe combined organic phase was dried over magnesium sulfate
  4. concentrationconcentrated
  5. washFlash chromatography on a silica gel bed (100 g) and elution with hexane/ethyl acetate (80:20)

Sources & evidence

ORD record
ord-353428eb7881432f849ffb17c593adff
Source dataset
uspto-grants-1997_01
Patent number
US05591733

Reaction notes

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