Sulfuric Acid → 1-[2-(4-Fluorophenyl)-8-nitroimidazo[1,2-a]pyridin-3-yl]ethanone

HRID 456684Notes

Reaction equation

HRID 456684 reaction equation
[F:1][C:2]1[CH:7]=[CH:6][C:5]([C:8]2[N:9]=[C:10]3[C:15]([N+:16]([O-:18])=[O:17])=[CH:14][CH:13]=[CH:12][N:11]3[CH:19]=2)=[CH:4][CH:3]=1.[C:20](OC(=O)C)(=[O:22])[CH3:21].S(=O)(=O)(O)O>>[F:1][C:2]1[CH:3]=[CH:4][C:5]([C:8]2[N:9]=[C:10]3[C:15]([N+:16]([O-:18])=[O:17])=[CH:14][CH:13]=[CH:12][N:11]3[C:19]=2[C:20](=[O:22])[CH3:21])=[CH:6][CH:7]=1

Participants

4

Reactant 3

HCID 1118Sulfuric AcidHCID 7918Acetic AnhydrideHCID 179762862-(4-Fluorophenyl)-8-nitroimidazo[1,2-a]pyridine

Product 1

HCID 695493021-[2-(4-Fluorophenyl)-8-nitroimidazo[1,2-a]pyridin-3-yl]ethanoneYield 55%

Procedure

2-(4-Fluorophenyl)-8-nitroimidazo[1,2-α]pyridine (2 g, 7.8 mmol) was added to acetic anhydride (15 mL). To this mixture was added a catalytic amount of concentrated sulfuric acid and the reaction mixture was heated to reflux for 1 hour. The resulting mixture was concentrated to a slurry, neutralized by addition of saturated aqueous sodium bicarbonate and extracted with ethyl acetate. The organic phase was dried (magnesium sulfate), filtered and concentrated to a solid. This solid was purified by silica gel chromatography (1:1 ethyl acetate:hexane) to give 1.3 g (55%) of 1-[2-(4-fluorophenyl)-8-nitroimidazo[1,2-α]pyridin-3-yl]ethanone as a brown solid. 1H NMR (DMSO-d6): δ 9.93 (d, 1H), 8.62 (d, 1H), 7.78 (q, 2H), 7.46 (m, 3H), 2.20 (s, 3H); MS m/z 300 (M+1).

Workup

  1. temperaturethe reaction mixture was heated
  2. temperatureto reflux for 1 hour
  3. concentrationThe resulting mixture was concentrated to a slurry
  4. additionneutralized by addition of saturated aqueous sodium bicarbonate
  5. extractionextracted with ethyl acetate
  6. dry with materialThe organic phase was dried (magnesium sulfate)
  7. filtrationfiltered
  8. concentrationconcentrated to a solid
  9. customThis solid was purified by silica gel chromatography (1:1 ethyl acetate:hexane)

Sources & evidence

ORD record
ord-6727b4f17d2341dbb89951027f074b7e
Source dataset
uspto-grants-2007_03
Patent number
US07186714B2

Reaction notes

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