Ethanol → 1-phenyl-3-(1-piperazinyl)-1H-indazole

HRID 359007Notes

Reaction equation

HRID 359007 reaction equation
C(OC([N:6]1[CH2:11][CH2:10][N:9]([C:12]2[C:20]3[C:15](=[CH:16][CH:17]=[CH:18][CH:19]=3)[N:14]([C:21]3[CH:26]=[CH:25][CH:24]=[CH:23][CH:22]=3)[N:13]=2)[CH2:8][CH2:7]1)=O)C.[OH-].[K+].C(O)C>O>[C:21]1([N:14]2[C:15]3[C:20](=[CH:19][CH:18]=[CH:17][CH:16]=3)[C:12]([N:9]3[CH2:10][CH2:11][NH:6][CH2:7][CH2:8]3)=[N:13]2)[CH:22]=[CH:23][CH:24]=[CH:25][CH:26]=1

Participants

5

Reactant 3

HCID 702EthanolHCID 14797Potassium HydroxideHCID 151170734-(1-phenyl-1H-indazol-3-yl)-1-piperazine carboxylic acid ethyl ester

Product 1

HCID 97956441-phenyl-3-(1-piperazinyl)-1H-indazoleYield 86.5%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

A stirred solution of 6.4 g of 4-(1-phenyl-1H-indazol-3-yl)-1-piperazine carboxylic acid ethyl ester, 6.1 g of potassium hydroxide in 60 ml of water, and 120 ml of ethanol was refluxed under nitrogen for 32 hours. The reaction mixture was concentrated in vacuo, diluted with water, and extracted with diethyl ether. The extract was washed with water and then with brine, dried over anhydrous magnesium sulfate, and concentrated to give 4.4 g of 1-phenyl-3-(1-piperazinyl)-1H-indazole as a solid. The solid was dissolved in ethyl acetate/diethyl ether and treated with ethereal hydrogen chloride to precipitate the hydrochloride salt. Recrystallization from methanol/diethyl ether gave 2.5 g (45%) of 1-phenyl-3-(1-piperazinyl-1H-indazole hydrochloride, mp 265°-267°.

Workup

  1. concentrationThe reaction mixture was concentrated in vacuo
  2. additiondiluted with water
  3. extractionextracted with diethyl ether
  4. washThe extract was washed with water
  5. dry with materialwith brine, dried over anhydrous magnesium sulfate
  6. concentrationconcentrated

Sources & evidence

ORD record
ord-a7f111c0ae9549de86c0eb7c4b86a6f5
Source dataset
uspto-grants-1991_03
Patent number
US04999356

Reaction notes

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