1-Benzyl-5-nitro-1H-indazole → 1-(Phenylmethyl)-1H-indazol-5-amine

HRID 1292966Notes

Reaction equation

HRID 1292966 reaction equation
[CH2:1]([N:8]1[C:16]2[C:11](=[CH:12][C:13]([N+:17]([O-])=O)=[CH:14][CH:15]=2)[CH:10]=[N:9]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1>C(O)(=O)C.[Fe]>[CH2:1]([N:8]1[C:16]2[C:11](=[CH:12][C:13]([NH2:17])=[CH:14][CH:15]=2)[CH:10]=[N:9]1)[C:2]1[CH:3]=[CH:4][CH:5]=[CH:6][CH:7]=1

Participants

4

Reactant 1

HCID 219520821-Benzyl-5-nitro-1H-indazole

Product 1

HCID 2120691-(Phenylmethyl)-1H-indazol-5-amineYield 86.1%

Reagents, catalysts & solvents 2

HCID 23925IronCatalystHCID 176Acetic AcidSolvent

Procedure

7.61 g (136 mmol, 5 equiv) of Iron powder (4.03 g, 72.1 mmol) was added slowly to the solution of 1-Benzyl-5-nitro-1H-indazole (6.9 g, 27.2 mmol) in acetic acid (200 mL). After stirring at room temperature overnight, the reaction mixture became milky with formation of a white precipitate. The precipitate was filtered off and the filtrate was concentrated to ca. 20 mL. The residue was diluted with water (200 mL) and neutralized by slow addition of sodium hydroxide. The mixture was then extracted with ethyl acetate (500×5 mL). The organic layer were combined, dried over sodium sulfate, filtered and concentrated to dryness to afford 1-benzyl-1H-indazol-5-ylamine (5.23 g, 82%) as a brown solid. 1H NMR (DMSO-d6): δ 7.72 (s, 1H), 7.35 (d, J=8.8 Hz, 1H), 7.24–7.14 (m, 5H), 6.74 (m, 2H), 5.49 (s, 2H), 4.80 (br, 2H). ES-LCMS: RT=0.93 min; [M+H]+=224.2.

Workup

  1. filtrationThe precipitate was filtered off
  2. concentrationthe filtrate was concentrated to ca. 20 mL
  3. additionThe residue was diluted with water (200 mL)
  4. additionneutralized by slow addition of sodium hydroxide
  5. extractionThe mixture was then extracted with ethyl acetate (500×5 mL)
  6. dry with materialdried over sodium sulfate
  7. filtrationfiltered
  8. concentrationconcentrated to dryness

Sources & evidence

ORD record
ord-afaa372102424f068e48e9cc4e712180
Source dataset
uspto-grants-2007_07
Patent number
US07238701B2

Reaction notes

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