Sodium Hydroxide → 4-oxo-4,5,6,7-tetrahydro-1H-indazole-3-carboxylic acid
Reaction equation
C([O:3][C:4]([C:6]1[C:14]2[C:13](=[O:15])[CH2:12][CH2:11][CH2:10][C:9]=2[NH:8][N:7]=1)=[O:5])C.[OH-].[Na+]>CO>[O:15]=[C:13]1[CH2:12][CH2:11][CH2:10][C:9]2[NH:8][N:7]=[C:6]([C:4]([OH:5])=[O:3])[C:14]1=2Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Conditions
- Temperature
- 60 °C
Procedure
A solution of 4-oxo-4,5,6,7-tetrahydro-1H-indazole-3-carboxylic acid ethyl ester (purity 90%, 1.84 g, 8.0 mmol) in methanol (20 mL) is treated with 10 N NaOH (4 mL) and stirred under nitrogen at 60° C. for 90 min. The solvent is evaporated under reduced pressure and the residue is dissolved in water (30 mL), treated with brine (30 mL) and acidified to pH 2 with conc. hydrochloric acid to produce a white precipitate. The mixture is cooled to 0° C. The precipitate is filtered, washed with water (5 mL), and dried in a vacuum oven to give 4-oxo-4,5,6,7-tetrahydro-1H-indazole-3-carboxylic acid. 1H NMR (DMSO-d6) 2.18 (quintet, J=6.2 Hz, 2H), 2.66 (t, J=6.4 Hz, 2H), 2.95 (t, J=6.2 Hz, 2H).
Workup
- customThe solvent is evaporated under reduced pressure
- dissolutionthe residue is dissolved in water (30 mL)
- additiontreated with brine (30 mL)
- customto produce a white precipitate
- temperatureThe mixture is cooled to 0° C
- filtrationThe precipitate is filtered
- washwashed with water (5 mL)
- customdried in a vacuum oven
Sources & evidence
- ORD record
- ord-5eba47eddb4c4f238a3ec31cbeb931ba
- Source dataset
- uspto-grants-2005_02
- Patent number
- US06852730B2
Reaction notes
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