Hydrochloric Acid → 3-(Piperazin-1-YL)-1H-indazole

HRID 55684Notes

Reaction equation

HRID 55684 reaction equation
C1(S([N:10]2[C:18]3[C:13](=[CH:14][CH:15]=[CH:16][CH:17]=3)[C:12]([N:19]3[CH2:24][CH2:23][N:22](C(OC4C=CC=CC=4)=O)[CH2:21][CH2:20]3)=[N:11]2)(=O)=O)C=CC=CC=1.[OH-].[K+].Cl>C(O)C>[N:19]1([C:12]2[C:13]3[C:18](=[CH:17][CH:16]=[CH:15][CH:14]=3)[NH:10][N:11]=2)[CH2:24][CH2:23][NH:22][CH2:21][CH2:20]1

Participants

5

Reactant 3

HCID 313Hydrochloric AcidHCID 14797Potassium HydroxideHCID 184672231-Benzenesulfonyl-3-(1-phenoxycarbonyl4-piperazinyl)-1H-indazole

Product 1

HCID 148234453-(Piperazin-1-YL)-1H-indazoleYield 94.9%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

To a suspension of 1-benzenesulfonyl-3-(1-phenoxycarbonyl-4-piperazinyl)-1H-indazole (31.3 g, 67.7 mmol) in ethanol (500 ml) was added 50% KOH (aq.) (100 g of KOH in 100 g H2O) at room temperature. The reaction mixture was warmed to reflux for 6.5 hours and cooled to room temperature. After adjusting the pH to about two using HCl (con., 120 ml), the volatiles were removed under reduced pressure. The remaining residue was diluted with water and removed via filtration. The aqueous filtrate was washed with EtOAc and basified to pH=8 using 50% NaOH (aq.). The product was extracted into 10:1 dichloromethane/isopropylalcohol. The combined organics were dried (MgSO4), filtered, and concentrated to give 13.0 g of desired 3-piperazin-1-yl-1H-indazole as a brown solid which was used without further purification.

Workup

  1. temperatureThe reaction mixture was warmed
  2. temperatureto reflux for 6.5 hours
  3. customthe volatiles were removed under reduced pressure
  4. additionThe remaining residue was diluted with water
  5. customremoved via filtration
  6. washThe aqueous filtrate was washed with EtOAc and basified to pH=8
  7. extractionThe product was extracted into 10:1 dichloromethane/isopropylalcohol
  8. dry with materialThe combined organics were dried (MgSO4)
  9. filtrationfiltered
  10. concentrationconcentrated

Sources & evidence

ORD record
ord-4b39e511e5304e038997358e1db032b3
Source dataset
uspto-grants-1997_04
Patent number
US05624927

Reaction notes

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