4-Nitroindazole → NoName_3327

HRID 876911Notes

Reaction equation

HRID 876911 reaction equation
[N+:1]([C:4]1[CH:12]=[CH:11][CH:10]=[C:9]2[C:5]=1[CH:6]=[N:7][NH:8]2)([O-])=O>[Pd].CCO>[NH2:1][C:4]1[CH:12]=[CH:11][CH:10]=[C:9]2[C:5]=1[CH:6]=[N:7][NH:8]2

Participants

4

Reactant 1

HCID 180574-Nitroindazole

Product 1

HCID 413085NoName_3327Yield 70.2%

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 702EthanolSolvent

Procedure

A mixture of 4-nitro-1H-indazole (200 g, 1.22 moles) and 10% palladium on carbon (20.0 g) in EtOH (3000 ml) was hydrogenated at ambient temperature (reaction was exothermic and temperature increased to 50° C.). After completion of reaction, the catalyst was removed by filtration. The solvent was evaporated under vacuum at below 80° C. and cooled to room temperature and n-hexane (1000 ml) was added to the residue and stirred for 30 min. Isolated solid was filtered and washed with n-hexane (200 ml). Product was dried under vacuum at 70-80° C. for 10-12 h to give 4-amino-1H-indazole as a brown solid (114 g, 70%), m. p.: 136-143° C. 1H NMR (200 MHz, CDCl3) δ 12 (br, 1H), 8.0 (s, 1H), 7.1-7.0 (dd, 2H), 6.5 (d, 1H), 3.9 (m, 2H). ESMS m/z 134 (M+1). Purity: 90-95% (HPLC)

Workup

  1. customwas hydrogenated at ambient temperature
  2. custom(reaction was exothermic and temperature increased to 50° C.)
  3. customAfter completion of reaction
  4. customthe catalyst was removed by filtration
  5. customThe solvent was evaporated under vacuum at below 80° C.
  6. additionn-hexane (1000 ml) was added to the residue
  7. customIsolated solid
  8. filtrationwas filtered
  9. washwashed with n-hexane (200 ml)
  10. customProduct was dried under vacuum at 70-80° C. for 10-12 h

Sources & evidence

ORD record
ord-3d0c997f7fd2443598b670523224fc0d
Source dataset
uspto-grants-2015_03
Patent number
US08987280B2

Reaction notes

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