Water → 5-bromo-1H-indazole

HRID 1973023Notes

Reaction equation

HRID 1973023 reaction equation
[Br:1][C:2]1[CH:3]=[CH:4][C:5](F)=[C:6]([CH:9]=1)[CH:7]=O.O.[NH2:12][NH2:13].O.C(OCC)(=O)C>C(O)CCC>[Br:1][C:2]1[CH:9]=[C:6]2[C:5](=[CH:4][CH:3]=1)[NH:13][N:12]=[CH:7]2

Participants

6

Reactant 4

HCID 962WaterHCID 8857Ethyl AcetateHCID 24654Hydrazine hydrate (1:1)HCID 7363275-Bromo-2-fluorobenzaldehyde

Product 1

HCID 7619295-bromo-1H-indazoleYield 30%

Reagents, catalysts & solvents 1

HCID 2631-ButanolSolvent

Conditions

Temperature
65 °C

Procedure

To an orange solution of 5-bromo-2-fluorobenzaldehyde (3.0 g, 14.78 mmol) in n-butanol (6 mL) was added hydrazine hydrate (11.1 g, 10.78 mL, 221.66 mmol) and the thick orange slurry was heated to 125° C. (became clear at 65° C.) in an oil bath for 21 h and cooled to rt. The mixture was poured into water (100 mL) and ethyl acetate (300 mL). The aqueous layer was isolated and extracted with ethyl acetate (100 mL). The combined organics were washed with brine, dried over Na2SO4 and concentrated. The product was isolated by column chromatography (33% ethyl acetate in hexanes) as a cream colored solid (0.86 g, 30%). LC-MS [M+H]+=197.1, RT=2.64 min.

Workup

  1. temperaturecooled to rt
  2. customThe aqueous layer was isolated
  3. extractionextracted with ethyl acetate (100 mL)
  4. washThe combined organics were washed with brine
  5. dry with materialdried over Na2SO4
  6. concentrationconcentrated

Sources & evidence

ORD record
ord-99ad4b31bc684e0ebbfec937bc38d733
Source dataset
uspto-grants-2013_04
Patent number
US08431695B2

Reaction notes

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