Hydrazine → 4,6-Dichloro-1H-indazole

HRID 246050Notes

Reaction equation

HRID 246050 reaction equation
[Cl:1][C:2]1[CH:9]=[C:8]([Cl:10])[CH:7]=[C:6](Cl)[C:3]=1[CH:4]=O.[NH2:12][NH2:13]>O1CCOCC1>[Cl:1][C:2]1[CH:9]=[C:8]([Cl:10])[CH:7]=[C:6]2[C:3]=1[CH:4]=[N:12][NH:13]2

Participants

4

Reactant 2

HCID 9321HydrazineHCID 53144572,4,6-Trichlorobenzaldehyde

Product 1

HCID 247281324,6-Dichloro-1H-indazoleYield 38.6%

Reagents, catalysts & solvents 1

HCID 312751,4-DioxaneSolvent

Conditions

Temperature
160 °C

Procedure

In a microwave vial 2,4,6-trichlorobenzaldehyde (4.0 g, 19.1 mmol) was dissolved in 1,4-dioxane (8 mL) and hydrazine (7.2 mL, 229 mmol) was added. The vial was sealed and heated under microwave irradiation at 160° C. for 30 min. The reaction was quenched with water and extracted with EtOAc. The organic layer was washed with brine then dried over MgSO4 and concentrated. The residue was purified by silica gel chromatography with 50% to 100% EtOAc/heptane to provide 1.38 g (38%) of 4,6-dichloro-1H-indazole as a white solid. 1H NMR (CDCl3, 300 MHz): δ (ppm) 8.14 (s, 1H), 7.44 (s, 1H), 7.20 (d, J=1.5 Hz, 15H).

Workup

  1. customThe vial was sealed
  2. customThe reaction was quenched with water
  3. extractionextracted with EtOAc
  4. washThe organic layer was washed with brine
  5. dry with materialthen dried over MgSO4
  6. concentrationconcentrated
  7. customThe residue was purified by silica gel chromatography with 50% to 100% EtOAc/heptane

Sources & evidence

ORD record
ord-59c2cb4064914a69b6762be6fac06471
Source dataset
uspto-grants-2014_02
Patent number
US08658646B2

Reaction notes

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