Oxonium, trimethyl-, tetrafluoroborate(1-) (1:1) → methyl 5-bromo-2-methyl-2H-indazole-4-carboxylate

HRID 887740Notes

Reaction equation

HRID 887740 reaction equation
[Br:1][C:2]1[CH:10]=[CH:9][C:8]2[NH:7][N:6]=[CH:5][C:4]=2[C:3]=1[C:11]([O:13][CH3:14])=[O:12].F[B-](F)(F)F.[CH3:20][O+](C)C>C(OCC)(=O)C.C(=O)([O-])O.[Na+]>[Br:1][C:2]1[CH:10]=[CH:9][C:8]2[C:4](=[CH:5][N:6]([CH3:20])[N:7]=2)[C:3]=1[C:11]([O:13][CH3:14])=[O:12]

Participants

5

Reactant 2

HCID 2735153Oxonium, trimethyl-, tetrafluoroborate(1-) (1:1)HCID 59145907Methyl 5-bromo-1H-indazole-4-carboxylate

Product 1

HCID 59145918methyl 5-bromo-2-methyl-2H-indazole-4-carboxylateYield 73%

Reagents, catalysts & solvents 2

HCID 8857Ethyl AcetateSolventHCID 516892Sodium BicarbonateSolvent

Procedure

To a solution of methyl 5-bromo-1H-indazole-4-carboxylate (4.50 g, 17.6 mmol) in ethyl acetate (176 mL) was added trimethyloxonium tetrafluoroborate (3.38 g, 22.9 mmol) at room temperature, and the mixture was stirred for 2.5 hr. The reaction solution was diluted with saturated aqueous sodium hydrogen carbonate solution, and the mixture was extracted with ethyl acetate. The extract was washed with saturated brine, and dried over anhydrous sodium sulfate. The solvent was evaporated under reduced pressure, and the residue was purified by silica gel column chromatography (ethyl acetate/hexane=5/95→30/70) to give the title compound (3.42 g, yield 73%).

Workup

  1. extractionthe mixture was extracted with ethyl acetate
  2. washThe extract was washed with saturated brine
  3. dry with materialdried over anhydrous sodium sulfate
  4. customThe solvent was evaporated under reduced pressure
  5. customthe residue was purified by silica gel column chromatography (ethyl acetate/hexane=5/95→30/70)

Sources & evidence

ORD record
ord-9b1512b7b80b42c992972a2910cf22bb
Source dataset
uspto-grants-2012_08
Patent number
US08247429B2

Reaction notes

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