Sodium Hydroxide → 1H-Indazole-5-carboxylic acid

HRID 22658Notes

Reaction equation

HRID 22658 reaction equation
[NH:1]1[C:9]2[C:4](=[CH:5][C:6]([C:10]([O:12]C)=[O:11])=[CH:7][CH:8]=2)[CH:3]=[N:2]1.[OH-].[Na+]>CO>[NH:1]1[C:9]2[C:4](=[CH:5][C:6]([C:10]([OH:12])=[O:11])=[CH:7][CH:8]=2)[CH:3]=[N:2]1

Participants

4

Reactant 2

HCID 14798Sodium HydroxideHCID 22260640Methyl 1H-indazole-5-carboxylate

Product 1

HCID 42484541H-Indazole-5-carboxylic acidYield 89%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

To a stirred solution of methyl 1H-indazole-5-carboxylate (500 mg, 2.84 mmol) in MeOH (15 mL) is added sodium hydroxide (20 mL of 2.5% aqueous solution). The mixture is heated at reflux for 1 h, followed by removal of the methanol in vacuo. The remaining aqueous solution is washed with EtOAc (5 mL), acidified with 1 N aqueous HCl to pH˜5-6. The resulting precipitate is collected by filtration, washed with water and dried in vacuo to afford 410 mg (89%) of 1H-indazole-5-carboxylic acid as a tan solid: IR (diffuse reflectance) 3290, 3115, 2964, 2954, 2813, 2606, 2557, 2505, 1687, 1627, 1321, 1274, 948, 937, 769 cm−1; 1H NMR (400 MHz, DMSO-d6) δ 13.4 12.7, 8.5 8.2, 7.9, 7.6.

Workup

  1. temperatureThe mixture is heated
  2. temperatureat reflux for 1 h
  3. customfollowed by removal of the methanol in vacuo
  4. washThe remaining aqueous solution is washed with EtOAc (5 mL)
  5. filtrationThe resulting precipitate is collected by filtration
  6. washwashed with water
  7. customdried in vacuo

Sources & evidence

ORD record
ord-f699b72f349f492ca48e1a00ea967a0e
Source dataset
uspto-grants-2005_02
Patent number
US06849620B2

Reaction notes

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