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

HRID 1639778Notes

Reaction equation

HRID 1639778 reaction equation
[F:1][C:2]1[CH:10]=[CH:9][C:8]2[C:4](=[CH:5][NH:6][N:7]=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.O>[F: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 178498690HCID 178498690, compound

Product 1

HCID 59334518methyl 5-fluoro-2-methyl-2H-indazole-4-carboxylateYield 85%

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 8857Ethyl AcetateSolvent

Procedure

To a solution of methyl 5-fluoro-2H-indazole-4-carboxylate (4.50 g, 23.2 mmol) in ethyl acetate (93 mL) was 25 added trimethyloxonium tetrafluoroborate (4.46 g, 30.1 mmol) at room temperature, and the mixture was stirred for 5 hr. The reaction solution was diluted with water, and the mixture was extracted with ethyl acetate. The extract was dried over anhydrous sodium sulfate and the solvent was evaporated under reduced pressure. The residue was purified by flash silica gel column chromatography (ethyl acetate/hexane=1/2) to give the title compound (4.10 g, yield 85%).

Workup

  1. customat room temperature
  2. extractionthe mixture was extracted with ethyl acetate
  3. dry with materialThe extract was dried over anhydrous sodium sulfate
  4. customthe solvent was evaporated under reduced pressure
  5. customThe residue was purified by flash silica gel column chromatography (ethyl acetate/hexane=1/2)

Sources & evidence

ORD record
ord-41f5b6be4f73490db99924fd3064f90f
Source dataset
uspto-grants-2012_02
Patent number
US08110585B2

Reaction notes

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