Hydrochloric Acid → 3-bromo-6-nitro-1H-indazole

HRID 1790170Notes

Reaction equation

HRID 1790170 reaction equation
[OH-].[Na+].[N+:3]([C:6]1[CH:14]=[C:13]2[C:9]([CH:10]=[N:11][NH:12]2)=[CH:8][CH:7]=1)([O-:5])=[O:4].[Br-:15].[Br-].[Br-].[NH+]1C=CC=CC=1.[NH+]1C=CC=CC=1.[NH+]1C=CC=CC=1.Cl>O.CO>[Br:15][C:10]1[C:9]2[C:13](=[CH:14][C:6]([N+:3]([O-:5])=[O:4])=[CH:7][CH:8]=2)[NH:12][N:11]=1

Participants

7

Reactant 4

HCID 313Hydrochloric AcidHCID 14798Sodium HydroxideHCID 242396-NitroindazoleHCID 21124087Pyridiniumtribromide

Product 1

HCID 1785264313-bromo-6-nitro-1H-indazole

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 962WaterSolvent

Conditions

Temperature
0 °C

Procedure

A mixture of NaOH (2.0 g, 50 mmol) in H2O (60 mL) was added 6-nitroindazole (2.0 g, 12 mmol) and the suspension heated until a red solution formed. The mixture was placed in an ice-water bath for 15 minutes after which pyridinium tribromide (4.7 g, 15 mmol) in MeOH (15 mL) was added. The mixture was stirred at 0° C. for 5 hours after which the pH was adjusted to 7 with diluted HCl. The mixture was extracted with ethyl acetate, and the combined organic layer washed with H2O and concentrated under reduced pressure. The residue was purified by flash chromatography to provide the title compound. 1H NMR (300 MHz, DMSO-d6) δ ppm 7.84 (m, 1H), 8.02 (m, 1H), 8.50 (m, 1H), 14.16 (s, 1H); MS (DCI/NH3) m/z 243[M+H]+.

Workup

  1. temperaturethe suspension heated until a red solution
  2. customformed
  3. extractionThe mixture was extracted with ethyl acetate
  4. washthe combined organic layer washed with H2O
  5. concentrationconcentrated under reduced pressure
  6. customThe residue was purified by flash chromatography

Sources & evidence

ORD record
ord-c2b7d8d1070148d98a5ad00d051f22d2
Source dataset
uspto-grants-2006_07
Patent number
US07071182B2

Reaction notes

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