Acetic Anhydride → methyl 1-acetyl-6-methyl-1H-indazole-5-carboxylate

HRID 1269869Notes

Reaction equation

HRID 1269869 reaction equation
C(OC(=O)C)(=O)C.[Br-].C([NH3+:13])CCC.C([O-])(=O)C.[K+].[C:19]([NH:22][C:23]1[C:32]([CH3:33])=[CH:31][C:26]([C:27]([O:29][CH3:30])=[O:28])=[C:25]([CH3:34])[CH:24]=1)(=[O:21])[CH3:20].N(OCCC(C)C)=O>C(OCC)(=O)C.CCCCCC.O>[C:19]([N:22]1[C:23]2[C:32](=[CH:31][C:26]([C:27]([O:29][CH3:30])=[O:28])=[C:25]([CH3:34])[CH:24]=2)[CH:33]=[N:13]1)(=[O:21])[CH3:20]

Participants

9

Reactant 5

HCID 7918Acetic AnhydrideHCID 8053Isoamyl NitriteHCID 327521Methyl 4-acetamido-2,5-dimethylbenzoateHCID 517044Potassium AcetateHCID 21904131N-butyl-ammonium bromide

Product 1

HCID 22933897methyl 1-acetyl-6-methyl-1H-indazole-5-carboxylateYield 201.8%

Reagents, catalysts & solvents 3

HCID 962WaterSolventHCID 8058HexaneSolventHCID 8857Ethyl AcetateSolvent2×

Procedure

Acetic anhydride (0.85 ml, 9.01 mmol), n-butylammonium bromide (0.0502 g, 0.156 mmol) and potassium acetate (0.587 g, 5.98 mmol) were added to a solution of methyl 4-(acetylamino)-2,5-dimethylbenzoate (0.661 g, 2.99 mmol) in ethyl acetate (5 ml), followed by adding thereto a solution of isoamyl nitrite (0.0458 g, 3.91 mmol) in ethyl acetate (2 ml), and the resulting mixture was stirred for 8 hours with heating under reflux. Water was added thereto, followed by extraction with ethyl acetate (three times), and the extract solution was dried over anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure and the resulting residue was purified by a silica gel column chromatography (hexane/ethyl acetate=5/1 to 1/1). The solid thus obtained was suspended in hexane and stirred to be washed, and then it was collected by filtration and dried under reduced pressure to obtain methyl 1-acetyl-6-methyl-1H-indazole-5-carboxylate (0.0731 g, 11%).

Workup

  1. additionby adding
  2. temperaturewith heating
  3. temperatureunder reflux
  4. extractionfollowed by extraction with ethyl acetate (three times)
  5. dry with materialthe extract solution was dried over anhydrous magnesium sulfate
  6. distillationThe solvent was distilled off under reduced pressure
  7. customthe resulting residue was purified by a silica gel column chromatography (hexane/ethyl acetate=5/1 to 1/1)
  8. customThe solid thus obtained
  9. washto be washed
  10. filtrationit was collected by filtration
  11. customdried under reduced pressure

Sources & evidence

ORD record
ord-220a7a2fb07e4a40839fbfb8a47d68b7
Source dataset
uspto-grants-2007_04
Patent number
US07199147B2

Reaction notes

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