Ethyl Acetate → 3-phenyl-1H-indazole-5-ol

HRID 1353656Notes

Reaction equation

HRID 1353656 reaction equation
[N+]([C:4]1[CH:5]=[C:6]2[C:10](=[CH:11][CH:12]=1)[NH:9][N:8]=[C:7]2[C:13]1[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=1)([O-])=O.[H][H].C(OCC)(=[O:23])C>[Pd].[Pd].[C]>[C:13]1([C:7]2[C:6]3[C:10](=[CH:11][CH:12]=[C:4]([OH:23])[CH:5]=3)[NH:9][N:8]=2)[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=1

Participants

6

Reactant 3

HCID 8857Ethyl AcetateHCID 6174445-Nitro-3-phenyl-1H-indazoleHCID 178418361HCID 178418361, compound

Product 1

HCID 224798623-phenyl-1H-indazole-5-olYield 28%

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 178418390HCID 178418390, compoundCatalyst

Conditions

Temperature
180 °C

Procedure

To a solution of 5-nitro-3-phenyl-1H-indazole (1.0 g, 4.2 mmol) in ethyl acetate (80 mL) was added palladium on activated carbon (Pd/carbon) then the reaction was subjected to an atmosphere of hydrogen. The reaction was stirred for 3 days when the Pd/carbon was filtered off and the solution concentrated to an oil under vacuo. The oil was then taken up in H2SO4 (6 mL) and water (60 mL) and the suspension was heated in a bomb to 180° C. for 2 days. The reaction was then cooled to room temperature, quenched with NaHCO3 (100 mL) and extracted with ethyl acetate (3×30 mL). The organic layers were combined and dried (Na2SO4) and concentrated to recover the title compound (250 mg, 28% yield). 1H NMR (CDCl3) δ 13.0 (s, 1H), 9.20 (s, 1H), 7.91 (s, 1H), 7.88 (s, 1H), 7.50 (t, 2H), 7.41 (d, 1H), 7.36 (t, 1H), 7.28 (s, 1H), 6.96 (dd, 1H); ES-MS (m/z) 195 [M+1]+.

Workup

  1. filtrationwas filtered off
  2. concentrationthe solution concentrated to an oil under vacuo
  3. temperatureThe reaction was then cooled to room temperature
  4. customquenched with NaHCO3 (100 mL)
  5. extractionextracted with ethyl acetate (3×30 mL)
  6. dry with materialdried (Na2SO4)
  7. concentrationconcentrated

Sources & evidence

ORD record
ord-79aee9b4e9d344bc91c91eed0c74f744
Source dataset
uspto-grants-2007_05
Patent number
US07220771B2

Reaction notes

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