p-Toluenesulfonic acid → 5,6-Dichloro-2-methylbenzimidazole

HRID 1596143Notes

Reaction equation

HRID 1596143 reaction equation
[Cl:1][C:2]1[C:7]([Cl:8])=[CH:6][C:5]([NH2:9])=[C:4]([NH2:10])[CH:3]=1.[C:11]1(C)C=CC(S(O)(=O)=O)=C[CH:12]=1.C(OCC)(OCC)(OCC)C>C1(C)C=CC=CC=1>[Cl:1][C:2]1[C:7]([Cl:8])=[CH:6][C:5]2[N:9]=[C:11]([CH3:12])[NH:10][C:4]=2[CH:3]=1

Participants

5

Reactant 3

HCID 6101p-Toluenesulfonic acidHCID 66221Triethyl orthoacetateHCID 792974,5-Dichloro-1,2-phenylenediamine

Product 1

HCID 6083195,6-Dichloro-2-methylbenzimidazole

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

A mixture of 4,5-dichloro-1,2-phenylenediamine (25 g, 0.14 mol) and a catalytic amount of p-toluenesulfonic acid suspended in toluene (200 mL) is heated to reflux in a 500 mL three-necked flask fitted with a reflux condenser and addition funnel. Triethyl orthoacetate (23 g, 0.14 mol) is added dropwise over the course of 2 hours. The reflux condenser is then replaced with a distillation head and approximately 50 mL of solvent (mixture of ethanol and toluene) is collected. The remaining reaction mixture is allowed to stand at room temperature overnight. The resulting solid is collected by suction filtration and dried under vacuum for 24 hrs. The product is used without further purification.

Workup

  1. temperatureis heated
  2. temperatureto reflux in a 500 mL three-necked flask
  3. customfitted with a reflux condenser and addition funnel
  4. customis collected
  5. customThe remaining reaction mixture
  6. filtrationThe resulting solid is collected by suction filtration
  7. customdried under vacuum for 24 hrs
  8. customThe product is used without further purification

Sources & evidence

ORD record
ord-8e04774a16084b848d2b71e0cce82f41
Source dataset
uspto-grants-2001_09
Patent number
US06291203B1

Reaction notes

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