Dimethyl Sulfate → 7-bromo-2-methyl-2H-indazole

HRID 902537Notes

Reaction equation

HRID 902537 reaction equation
[Br:1][C:2]1[CH:3]=[CH:4][CH:5]=[C:6]2[C:10]=1[NH:9][N:8]=[CH:7]2.S(OC)(O[CH3:15])(=O)=O>C1(C)C=CC=CC=1>[Br:1][C:2]1[C:10]2[C:6](=[CH:7][N:8]([CH3:15])[N:9]=2)[CH:5]=[CH:4][CH:3]=1

Participants

4

Reactant 2

HCID 6497Dimethyl SulfateHCID 203238997-Bromo-1H-indazole

Product 1

HCID 210945807-bromo-2-methyl-2H-indazoleYield 73%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

A solution of 7-bromo-1H-indazole (3; 1.71 g, 8.67 mmol) and dimethyl sulfate (0.90 mL, 9.5 mmol) in 30 mL of toluene was stirred at 110° C. for 4 h, then allowed to cool. The mixture was carefully washed with 30 mL of a saturated aqueous NaHCO3 solution, dried over MgSO4, filtered (rinsing with diethyl ether), and concentrated to an orange oil Column chromatography (0→50% EtOAc/hexanes) afforded 7-bromo-2-methyl-2H-indazole (6: R=Me; 1.33 g, 73%) as a light tan solid.

Workup

  1. temperatureto cool
  2. washThe mixture was carefully washed with 30 mL of a saturated aqueous NaHCO3 solution
  3. dry with materialdried over MgSO4
  4. filtrationfiltered
  5. wash(rinsing with diethyl ether)
  6. concentrationconcentrated to an orange oil Column chromatography (0→50% EtOAc/hexanes)

Sources & evidence

ORD record
ord-5bcfa2faa1864037a7c56f18f17778b1
Source dataset
uspto-grants-2008_04
Patent number
US07365211B2

Reaction notes

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