Formic Acid → 5-Trifluoromethyl-1H-benzimidazole

HRID 2227195Notes

Reaction equation

HRID 2227195 reaction equation
[F:1][C:2]([F:12])([F:11])[C:3]1[CH:8]=[CH:7][C:6]([NH2:9])=[C:5]([NH2:10])[CH:4]=1.[CH:13](O)=O>>[F:1][C:2]([F:11])([F:12])[C:3]1[CH:8]=[CH:7][C:6]2[N:9]=[CH:13][NH:10][C:5]=2[CH:4]=1

Participants

3

Reactant 2

HCID 284Formic AcidHCID 5208224-Trifluoromethyl-1,2-phenylenediamine

Product 1

HCID 3494445-Trifluoromethyl-1H-benzimidazoleYield 83%

Procedure

A mixture of 10 g (60 mmol) of 4-(trifluoromethyl)-1,2-phenylenediamine (Lancaster) and 50 mL of formic acid was refluxed for 2 h. Excess formic acid was then removed in vacuo. To the resultant concentrate was added 200 mL of water during which time a precipitate was discerned. This was filtered and discarded. The filtrate was concentrated in vacuo and redissolved in EtOAc. After repeated washing with saturated NaHCO3, the EtOAc solution was dried over MgSO4 and concentrated. The concentrate was put on a vacuum pump overnight. This resulted in 9.27 g (83%) of a yellow solid. 1H NMR (DMSO-d6) δ7.5 (d,1H, aromatic), 7.8 (d, 1H, aromatic), 8 (s, 1H, aromatic), 8.4 (s, 1H, CH), 12.8 (br s, 1H, NH).

Workup

  1. temperaturewas refluxed for 2 h
  2. customExcess formic acid was then removed in vacuo
  3. concentrationTo the resultant concentrate
  4. additionwas added 200 mL of water during which time a precipitate
  5. filtrationThis was filtered
  6. concentrationThe filtrate was concentrated in vacuo
  7. dissolutionredissolved in EtOAc
  8. washAfter repeated washing with saturated NaHCO3
  9. dry with materialthe EtOAc solution was dried over MgSO4
  10. concentrationconcentrated
  11. customwas put on a vacuum pump overnight

Sources & evidence

ORD record
ord-2c362a328bcd4e6f9a5b5f0e72246fc0
Source dataset
uspto-grants-2002_07
Patent number
US06413938B1

Reaction notes

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