Acetic Anhydride → 1-(5-Bromo-1H-indazol-1-yl)ethanone

HRID 240775Notes

Reaction equation

HRID 240775 reaction equation
[Br:1][C:2]1[CH:8]=[CH:7][C:5]([NH2:6])=[C:4]([CH3:9])[CH:3]=1.[C:10]([O:13]C(=O)C)(=O)[CH3:11].C([O-])(=O)C.[K+].C(O[N:28]=O)CC(C)C.C(=O)(O)[O-].[Na+]>C(Cl)(Cl)Cl>[Br:1][C:2]1[CH:3]=[C:4]2[C:5](=[CH:7][CH:8]=1)[N:6]([C:10](=[O:13])[CH3:11])[N:28]=[CH:9]2

Participants

7

Reactant 5

HCID 7918Acetic AnhydrideHCID 8053Isoamyl NitriteHCID 114234-Bromo-2-methylanilineHCID 516892Sodium BicarbonateHCID 517044Potassium Acetate

Product 1

HCID 152786101-(5-Bromo-1H-indazol-1-yl)ethanone

Reagents, catalysts & solvents 1

HCID 6212ChloroformSolvent

Conditions

Temperature
5 °C

Procedure

4-Bromo-2-methylaniline (25.0 g, 134 mmol) was dissolved in chloroform (250 mL), and the mixture was cooled to 5° C. Acetic anhydride (35 mL, 343 mmol) was added dropwise, and the mixture was allowed to warm to ambient temperature. Potassium acetate (3.97 g, 40.4 mmol) and isoamylnitrite (35 mL, 262 mmol) were added, and the mixture was heated at 70° C. overnight. The mixture was neutralized with saturated sodium bicarbonate and extracted with methylene chloride. The combined organic layers were concentrated under reduced pressure, and the resulting residue was triturated with methanol to afford the title compound. 1H NMR (300 MHz, DMSO-d6) δ ppm 8.45 (s, 1H) 8.26 (d, J=8.82 Hz, 1H) 8.17 (d, J=1.70 Hz, 1H) 7.77 (dd, J=8.82, 2.03 Hz, 1H) 2.72 (s, 3H).

Workup

  1. temperatureto warm to ambient temperature
  2. temperaturethe mixture was heated at 70° C. overnight
  3. extractionextracted with methylene chloride
  4. concentrationThe combined organic layers were concentrated under reduced pressure
  5. customthe resulting residue was triturated with methanol

Sources & evidence

ORD record
ord-ed25ac60d04748599c43bb8c7720e1b6
Source dataset
uspto-grants-2014_02
Patent number
US08648069B2

Reaction notes

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