5-Nitrofurfural → HCID 86623874, compound

HRID 1696633Notes

Reaction equation

HRID 1696633 reaction equation
[F:1][C:2]1[C:11]([F:12])=[CH:10][C:5]2[NH:6][C:7](=[S:9])[NH:8][C:4]=2[CH:3]=1.[H-].[Na+].[N+]([C:18]1[O:22][C:21]([CH:23]=[O:24])=[CH:20][CH:19]=1)([O-])=O>O1CCCC1>[F:12][C:11]1[C:2]([F:1])=[CH:3][C:4]2[NH:8][C:7]([S:9][C:18]3[O:22][C:21]([CH:23]=[O:24])=[CH:20][CH:19]=3)=[N:6][C:5]=2[CH:10]=1

Participants

5

Reactant 3

HCID 127745-NitrofurfuralHCID 24758Sodium hydrideHCID 106791065,6-difluoro-1H-benzimidazole-2-thiol

Product 1

HCID 86623874HCID 86623874, compoundYield 77.1%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

5,6-Difluoro-1,3-dihydro-benzimidazole-2-thione (1.0 g, 5.37 mmol) is suspended into 50 mL of tetrahydrofuran under argon. Then, 0.39 g (8.06 mmol) of sodium hydride is added. The reaction mixture is stirred at room temperature until gas evolution has ceased. 5-Nitro-2-furaldehyde (0.76 g, 5.37 mmol) is then added and the reaction mixture is stirred at room temperature for 16 h, upon which it is poured on ice and extracted 3 times with ethyl acetate. The organic extracts are combined, washed with brine, dried on magnesium sulfate, filtered and concentrated under reduced pressure. The residue is purified by chromatography on a prepacked 200 g 15-40 μm silica gel cartridge (eluting solvent: dichloromethane/methanol 95/5 v/v; rate: 40 mL/min). The fractions containing the desired product are combined and concentrated to dryness under reduced pressure. The residue is recrystallized from ethyl acetate/n-heptane, filtered, washed with n-heptane and dried under reduced pressure. 1.16 g of 5-(5,6-difluoro-1H-benzimidazol-2-ylsulfanyl)-furan-2-carbaldehyde is obtained as a crystalline brown powder. mp: 133° C.

Workup

  1. stirringthe reaction mixture is stirred at room temperature for 16 h, upon which it
  2. additionis poured on ice
  3. extractionextracted 3 times with ethyl acetate
  4. washwashed with brine
  5. customdried on magnesium sulfate
  6. filtrationfiltered
  7. concentrationconcentrated under reduced pressure
  8. customThe residue is purified by chromatography on a prepacked 200 g 15-40 μm silica gel cartridge (eluting solvent: dichloromethane/methanol 95/5 v/v; rate: 40 mL/min)
  9. additionThe fractions containing the desired product
  10. concentrationconcentrated to dryness under reduced pressure
  11. customThe residue is recrystallized from ethyl acetate/n-heptane
  12. filtrationfiltered
  13. washwashed with n-heptane
  14. customdried under reduced pressure

Sources & evidence

ORD record
ord-eac283086483441ca3618612e59df3d3
Source dataset
uspto-grants-2012_04
Patent number
US08163768B2

Reaction notes

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