3-Nitropyridin-2-ylamine → 2-(4-Fluorophenyl)-8-nitroimidazo[1,2-a]pyridine

HRID 456683

Reaction equation

HRID 456683 reaction equation
[NH2:1][C:2]1[C:7]([N+:8]([O-:10])=[O:9])=[CH:6][CH:5]=[CH:4][N:3]=1.Br[CH2:12][C:13]([C:15]1[CH:20]=[CH:19][C:18]([F:21])=[CH:17][CH:16]=1)=O>CN(C)C=O>[F:21][C:18]1[CH:19]=[CH:20][C:15]([C:13]2[N:1]=[C:2]3[C:7]([N+:8]([O-:10])=[O:9])=[CH:6][CH:5]=[CH:4][N:3]3[CH:12]=2)=[CH:16][CH:17]=1

Participants

4

Reactant 2

HCID 778873-Nitropyridin-2-ylamineHCID 967492-Bromo-1-(4-fluorophenyl)ethan-1-one

Product 1

HCID 179762862-(4-Fluorophenyl)-8-nitroimidazo[1,2-a]pyridineYield 36.4%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Procedure

To a solution of 2-amino-3-nitropyridine (1.3 g, 9.3 mmol) in N,N-dimethylformamide (20 mL) was added 2-bromo-4′-fluoroacetophenone (2 g, 9.3 mmol) and the reaction mixture was heated at reflux for 6 hours. The resulting mixture was concentrated to a solid in vacuo. This residue was dissolved in dichloromethane and the organic phase was washed with aqueous sodium bicarbonate and an aqueous sodium chloride solution. The organic phase was dried (magnesium sulfate), filtered through a silica gel pad and concentrated to give a solid. This solid was recrystallized from methanol to give 870 mg (36%) of 2-(4-fluorophenyl)-8-nitroimidazo[1,2-α]pyridine as a brown solid. 1H NMR (d6-DMSO): δ 8.98 (d, 1H), 8.69 (s,1H), 8.32 (d, 1H), 8.10 (q, 2H), 7.36 (t, 2H), 7.15 (t, 1H); 19F NMR (DMSO-d6) δ −113.7; MS m/z 258 (M+1).

Workup

  1. temperaturethe reaction mixture was heated
  2. temperatureat reflux for 6 hours
  3. concentrationThe resulting mixture was concentrated to a solid in vacuo
  4. dissolutionThis residue was dissolved in dichloromethane
  5. washthe organic phase was washed with aqueous sodium bicarbonate
  6. dry with materialThe organic phase was dried (magnesium sulfate)
  7. filtrationfiltered through a silica gel pad
  8. concentrationconcentrated
  9. customto give a solid
  10. customThis solid was recrystallized from methanol

Sources & evidence

ORD record
ord-55a334e591de4e1187675bab72ccfefd
Source dataset
uspto-grants-2007_03
Patent number
US07186714B2

Linked notes

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