Potassium Hydroxide → 1-(2-chlorophenyl)-3-(1-piperazinyl)-1H-indazole

HRID 359014Notes

Reaction equation

HRID 359014 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][C:22]=3[Cl:27])[N:13]=2)[CH2:8][CH2:7]1)=O)C.[OH-].[K+]>O>[Cl:27][C:22]1[CH:23]=[CH:24][CH:25]=[CH:26][C:21]=1[N:14]1[C:15]2[C:20](=[CH:19][CH:18]=[CH:17][CH:16]=2)[C:12]([N:9]2[CH2:10][CH2:11][NH:6][CH2:7][CH2:8]2)=[N:13]1

Participants

4

Reactant 2

HCID 14797Potassium HydroxideHCID 151170784-[1-(2-chlorophenyl)-1H-indazol-3-yl]-1-piperazine carboxylic acid ethyl ester

Product 1

HCID 151170791-(2-chlorophenyl)-3-(1-piperazinyl)-1H-indazole

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

A stirred mixture of 28.7 g of 4-[1-(2-chlorophenyl)-1H-indazol-3-yl]-1-piperazine carboxylic acid ethyl ester, 450 ml of 2-methoxymethanol, and a solution of 25 g of potassium hydroxide in 250 ml of water, was refluxed for 16 hours, cooled to ambient temperature, concentrated to about one-third of its volume, poured into water, and extracted with ethyl acetate. The extract was washed with water, dried over anhydrous magnesium sulfate, and concentrated to yield 1-(2-chlorophenyl)-3-(1-piperazinyl)-1H-indazole as an oil. The oil was dissolved in anhydrous diethyl ether and treated with ethereal hydrogen chloride to precipitate the hydrochloride salt. The salt was recrystallized from acetonitrile to yield 18.8 g (72%) of 1-(2-chlorophenyl)-2-(1-piperazinyl)-1H-indazole hydrochloride. Recrystallization from isopropyl alcohol-diethyl ether afforded the analytical sample, m.p. 197°-199°.

Workup

  1. concentrationconcentrated to about one-third of its volume
  2. additionpoured into water
  3. extractionextracted with ethyl acetate
  4. washThe extract was washed with water
  5. dry with materialdried over anhydrous magnesium sulfate
  6. concentrationconcentrated

Sources & evidence

ORD record
ord-2512c15e868e4c8289a9e7e657498cc8
Source dataset
uspto-grants-1991_03
Patent number
US04999356

Reaction notes

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