5-bromo-7-ethyl-1H-indazole → 7-ethyl-1H-indazole

HRID 246540Notes

Reaction equation

HRID 246540 reaction equation
Br[C:2]1[CH:3]=[C:4]2[C:8](=[C:9]([CH2:11][CH3:12])[CH:10]=1)[NH:7][N:6]=[CH:5]2>C(O)C.[Pd]>[CH2:11]([C:9]1[CH:10]=[CH:2][CH:3]=[C:4]2[C:8]=1[NH:7][N:6]=[CH:5]2)[CH3:12]

Participants

4

Reactant 1

HCID 211021955-bromo-7-ethyl-1H-indazole

Product 1

HCID 126391947-ethyl-1H-indazoleYield 131.8%

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 702EthanolSolvent

Procedure

To a solution of 5-bromo-7-ethyl-1H-indazole (900 mg, 4.00 mmol) in ethanol (16.0 mL) flushed with nitrogen was added palladium on carbon (128 mg, 1.2 mmol) and the mixture stirred under H2 at 1 atm. After 70 h the reaction was filtered over a pad of celite. The filtrate was collected and concentrated. The residue was dissolved in ethanol and 80 mg of palladium on carbon was added and stirred under H2 at 1 atm. After 3 h another 80 mg of palladium on carbon was added and stirred under H2 at 1 atm. After 16 h the reaction was filtered through a pad of celite. The filtrate was collected and concentrated. The yellow solid obtained was triturated with ether, filtered and dried under vacuum to give 7-ethyl-1H-indazole (771 mg, 5.27 mmol, 119%) as an off white solid. This was used directly without further purification. MS (M+H)+=146.8; 1H NMR (CDCl3) δ: 8.54 (s, 1H), 7.78 (d, J=8.2 Hz, 1H), 7.59 (d, J=7.1 Hz, 1H), 7.43 (t, J=7.1 Hz, 1H), 3.25 (q, J=7.4 Hz, 2H), 1.48 (t, J=7.5 Hz, 3H).

Workup

  1. filtrationAfter 70 h the reaction was filtered over a pad of celite
  2. customThe filtrate was collected
  3. concentrationconcentrated
  4. dissolutionThe residue was dissolved in ethanol
  5. addition80 mg of palladium on carbon was added
  6. stirringstirred under H2 at 1 atm
  7. additionAfter 3 h another 80 mg of palladium on carbon was added
  8. stirringstirred under H2 at 1 atm
  9. filtrationAfter 16 h the reaction was filtered through a pad of celite
  10. customThe filtrate was collected
  11. concentrationconcentrated
  12. customThe yellow solid obtained
  13. customwas triturated with ether
  14. filtrationfiltered
  15. customdried under vacuum

Sources & evidence

ORD record
ord-b4873e660d1e46f7b7cd14a4bbbc064d
Source dataset
uspto-grants-2014_02
Patent number
US08658646B2

Reaction notes

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