Dimethylformamide → 1-benzyl-4-nitro-1H-indazole

HRID 706750Notes

Reaction equation

HRID 706750 reaction equation
[N+:1]([C:4]1[CH:12]=[CH:11][CH:10]=[C:9]2[C:5]=1[CH:6]=[N:7][NH:8]2)([O-:3])=[O:2].[CH2:13](Br)[C:14]1[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=1.C(=O)([O-])[O-].[K+].[K+].CN(C=O)C>O>[CH2:13]([N:8]1[C:9]2[C:5](=[C:4]([N+:1]([O-:3])=[O:2])[CH:12]=[CH:11][CH:10]=2)[CH:6]=[N:7]1)[C:14]1[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=1

Participants

6

Reactant 4

HCID 6228DimethylformamideHCID 7498Benzyl BromideHCID 11430Potassium CarbonateHCID 180574-Nitroindazole

Product 1

HCID 213272561-benzyl-4-nitro-1H-indazoleYield 47%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

4-Nitro-1H-indazole (1.00 g; 6.13 mmol), benzyl bromide (1.15 g; 6.74 mmol) and potassium carbonate (1.69 g; 12.3 mmol) were mixed with DMF (15 mL) and stirred at ambient temperature under nitrogen for 16 hours. The reaction mixture was added to water (50 mL) and extracted into ethyl acetate. The combined extracted were dried (sodium sulfate), filtered and evaporated under reduced pressure to give a brown solid. The material was purified by silica gel chromatography eluting with hexane/ethyl acetate (20:1 to 10:1 to 5:1). The first component to elute was the desired regioisomer, which was obtained as a yellow solid (730 mg). The other regioisomer was the second component to elute (650 mg).

Workup

  1. extractionextracted into ethyl acetate
  2. extractionThe combined extracted
  3. dry with materialwere dried (sodium sulfate)
  4. filtrationfiltered
  5. customevaporated under reduced pressure
  6. customto give a brown solid
  7. customThe material was purified by silica gel chromatography
  8. washeluting with hexane/ethyl acetate (20:1 to 10:1 to 5:1)
  9. washThe first component to elute

Sources & evidence

ORD record
ord-733ae552965847ba8e32f97724001312
Source dataset
uspto-grants-2015_11
Patent number
US09174981B2

Reaction notes

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