Hydrazine → 3-phenyl-1H-indazole

HRID 1349585

Reaction equation

HRID 1349585 reaction equation
F[C:2]1[CH:15]=[CH:14][CH:13]=[CH:12][C:3]=1[C:4]([C:6]1[CH:11]=[CH:10][CH:9]=[CH:8][CH:7]=1)=O.[NH2:16][NH2:17]>O>[C:6]1([C:4]2[C:3]3[C:2](=[CH:15][CH:14]=[CH:13][CH:12]=3)[NH:17][N:16]=2)[CH:7]=[CH:8][CH:9]=[CH:10][CH:11]=1

Participants

4

Reactant 2

HCID 9321HydrazineHCID 676502-Fluorobenzophenone

Product 1

HCID 3003853-phenyl-1H-indazoleYield 67%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
170 °C

Procedure

To 2-fluorobenzophenone (1.0 g, 5.0 mmol) was added hydrazine (5 mL) and the reaction was heated to reflux for 3 hours. The reaction was then added to water (100 mL) and extracted with ethyl acetate (3×30 mL). The combined organic layers were dried with sodium sulfate (Na2SO4) and concentrated to an oil. The subsequent hydrazine adduct was heated with pyridine (20 mL) to 170° C. for 4 days. Pyridine was then removed under vacuum and the resulting oil taken up in water (100 mL) and extracted with ethyl acetate (3×30 mL). The combined ethyl acetate layers were dried (Na2SO4) and concentrated to give the final compound (650 mg, 67% yield). 1H NMR (CDCl3) δ 10.6 (br s, 1H), 8.04–7.99 (m, 2H), 7.56–7.50 (m, 2H), 7.47–7.33 (m, 2H), 7.29–7.19 (m, 3H); ES-MS (m/z) 195 [M+1]+.

Workup

  1. temperaturethe reaction was heated
  2. temperatureto reflux for 3 hours
  3. extractionextracted with ethyl acetate (3×30 mL)
  4. dry with materialThe combined organic layers were dried with sodium sulfate (Na2SO4)
  5. concentrationconcentrated to an oil
  6. customPyridine was then removed under vacuum
  7. extractionextracted with ethyl acetate (3×30 mL)
  8. dry with materialThe combined ethyl acetate layers were dried (Na2SO4)
  9. concentrationconcentrated

Sources & evidence

ORD record
ord-27793a7a0d4d4d22aa614cf7a42cbbd5
Source dataset
uspto-grants-2007_05
Patent number
US07211594B2

Linked notes

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