4-Chloro-2-methyl-3-nitroaniline → 5-chloro-4-nitro-1H-indazole

HRID 2423309Notes

Reaction equation

HRID 2423309 reaction equation
[Cl:1][C:2]1[CH:8]=[CH:7][C:5]([NH2:6])=[C:4]([CH3:9])[C:3]=1[N+:10]([O-:12])=[O:11].[N:13]([O-])=O.[Na+]>C(O)(=O)C>[N+:10]([C:3]1[C:2]([Cl:1])=[CH:8][CH:7]=[C:5]2[C:4]=1[CH:9]=[N:13][NH:6]2)([O-:12])=[O:11]

Participants

4

Reactant 2

HCID 187897374-Chloro-2-methyl-3-nitroanilineHCID 23668193Sodium Nitrite

Product 1

HCID 179892685-chloro-4-nitro-1H-indazole

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent2×

Procedure

To 4-chloro-2-methyl-3-nitroaniline (1.63 g, 8.8 mmol) dissolved in acetic acid (75 mL) at room temperature was added a 2M aqueous solution of sodium nitrite (4.4 mL). The suspension was then diluted with acetic acid (100 mL) and then heated at reflux for 4 h. The mixture was then cooled to room temperature and concentrated under reduced pressure. The residue was then partitioned between ethyl acetate (100 mL) and saturated aqueous sodium hydrogen carbonate solution (100 mL). The separated organic layer was then washed with brine, dried over magnesium sulfate and concentrated under reduced pressure. Column chromatography of the reside (hexane/ethyl acetate (2:1) afforded the desired product. 1H NMR (500 MHz) (DMSO-d6) δ 8.32 (s, 1H); 7.95 (d, J=8.7 Hz, 1H); 7.68 (d, J=8.7 Hz, 1H).

Workup

  1. temperatureheated
  2. temperatureat reflux for 4 h
  3. concentrationconcentrated under reduced pressure
  4. customThe residue was then partitioned between ethyl acetate (100 mL) and saturated aqueous sodium hydrogen carbonate solution (100 mL)
  5. washThe separated organic layer was then washed with brine
  6. dry with materialdried over magnesium sulfate
  7. concentrationconcentrated under reduced pressure

Sources & evidence

ORD record
ord-d7b2def63af0425797cfee65d389b5e7
Source dataset
uspto-grants-2011_06
Patent number
US07960567B2

Reaction notes

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