Formic Acid → 5,6-Dichloro-1H-benzimidazole

HRID 2300799Notes

Reaction equation

HRID 2300799 reaction equation
[NH2:1][C:2]1[CH:7]=[C:6]([Cl:8])[C:5]([Cl:9])=[CH:4][C:3]=1[NH2:10].[CH:11](O)=O>>[Cl:8][C:6]1[C:5]([Cl:9])=[CH:4][C:3]2[N:10]=[CH:11][NH:1][C:2]=2[CH:7]=1

Participants

3

Reactant 2

HCID 284Formic AcidHCID 792974,5-Dichloro-1,2-phenylenediamine

Product 1

HCID 3317755,6-Dichloro-1H-benzimidazole

Conditions

Temperature
100 °C

Procedure

A solution of 200 mg of 1,2-diamino-4,5-dichlorobenzene dissolved in 5 mL of 97% formic acid was heated to 100° C. in a sealed tube for 15 hours. After cooling to room temperature, the reaction was quenched by the addition of 3.3 mL of concentrated aqueous NH4OH and stirred for 30 minutes. Following dilution with 20 mL of H2O, and extraction with 2×20 mL EtOAc, the organic phases were dried over MgSO4 and concentrated under reduced pressure to yield 210 mg of the title compound as a brown oil. No further purification was performed. RF: 0.38 (5% MeOH in CH2Cl2). 1H NMR (500 MHz, CD3OD): δ 8.22 (s, 1H), 7.74 (s, 2H). Mass Spectrum (ESI) 188 (M+1).

Workup

  1. temperatureAfter cooling to room temperature
  2. customthe reaction was quenched by the addition of 3.3 mL of concentrated aqueous NH4OH
  3. extractionwith 20 mL of H2O, and extraction with 2×20 mL EtOAc
  4. dry with materialthe organic phases were dried over MgSO4
  5. concentrationconcentrated under reduced pressure

Sources & evidence

ORD record
ord-124998b079c34d48aabb7758816b2871
Source dataset
uspto-grants-2002_12
Patent number
US06498165B1

Reaction notes

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