5-bromo-1H-indazole → 5-Bromo-2-methyl-2H-indazole

HRID 2079739Notes

Reaction equation

HRID 2079739 reaction equation
F[B-](F)(F)F.[CH3:6][O+](C)C.[Br:10][C:11]1[CH:12]=[C:13]2[C:17](=[CH:18][CH:19]=1)[NH:16][N:15]=[CH:14]2>C(OCC)(=O)C>[Br:10][C:11]1[CH:19]=[CH:18][C:17]2[C:13](=[CH:14][N:15]([CH3:6])[N:16]=2)[CH:12]=1

Participants

4

Reactant 2

HCID 7619295-bromo-1H-indazoleHCID 2735153Oxonium, trimethyl-, tetrafluoroborate(1-) (1:1)

Product 1

HCID 115140075-Bromo-2-methyl-2H-indazoleYield 70%

Reagents, catalysts & solvents 1

HCID 8857Ethyl AcetateSolvent

Procedure

Add at room temperature under nitrogen, trimethyloxonium tetrafluoroborate (229.34; g, 1.52; mol) portion wise to a mixture of 5-bromo-1H-indazole (199.6; g, 1.01 mol) in ethyl acetate (3.04; L, 31.06; mol), stir 2.5; h and filter to give a white solid. Wash the recovered solid twice with ethyl acetate (500; mL) and then add it portion wise to a cooled aqueous solution of 2; M sodium hydroxide (3.80; L, 7.60; mol) in an ice bath. Stir the mixture for 1; h, sonicate for 15; min., filter and wash the recovered solid twice with water (200; mL). Dry the solid overnight under vacuum, slurry in dichloromethane (1; L) and filter. Concentrate the filtrate and purify by silica gel chromatography eluting with dichloromethane to give the title compound as a yellow solid (149.77; g, 70%). MS (m/z): 211, 213; (M+1).

Workup

  1. additionAdd at room temperature under nitrogen
  2. filtrationh and filter
  3. customto give a white solid
  4. washWash the recovered solid twice with ethyl acetate (500; mL)
  5. additionadd it portion wise to a cooled aqueous solution of 2
  6. stirringStir the mixture for 1
  7. customh, sonicate for 15
  8. filtration, filter
  9. washwash the recovered solid twice with water (200; mL)
  10. dry with materialDry the solid overnight under vacuum, slurry in dichloromethane (1; L)
  11. filtrationfilter
  12. concentrationConcentrate the filtrate
  13. custompurify by silica gel chromatography
  14. washeluting with dichloromethane

Sources & evidence

ORD record
ord-8f4e045fa6984c9985034046029aa7f4
Source dataset
uspto-grants-2011_04
Patent number
US07932274B2

Reaction notes

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