2-Aminobenzimidazole → 1H-benzimidazole-1,2-diamine

HRID 248425Notes

Reaction equation

HRID 248425 reaction equation
[NH2:1]OS(O)(=O)=O.[NH2:7][C:8]1[NH:9][C:10]2[CH:16]=[CH:15][CH:14]=[CH:13][C:11]=2[N:12]=1.[OH-].[K+]>O>[NH2:1][N:9]1[C:10]2[CH:16]=[CH:15][CH:14]=[CH:13][C:11]=2[N:12]=[C:8]1[NH2:7]

Participants

5

Reactant 3

HCID 136242-AminobenzimidazoleHCID 14797Potassium HydroxideHCID 76284hydroxylamine-O-sulfonic acid

Product 1

HCID 4309891H-benzimidazole-1,2-diamine

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

Hydroxylamine O-sulphonic acid (tech. 23.25 g, 205 mmol) was added to a stirred solution of 2-aminobenzimidazole (25 g, 187.5 mmol) dissolved in water (600 ml) containing potassium hydroxide (24.6 g, 438 mmol) at 23° C. After a few moments a white solid began to precipitate. The mixture was stirred for 30 mins and the product collected by filtration, washed with water and dried in air at ambient temperature, 10.75 g. On standing overnight a second crop, 5.8 g was obtained. The total yield of product was 16.55 g, 60%, mp. 252°-254° C., (lit. 255°-259° C.). Spectroscopic analysis was consistent with the product but indicated a small amount of the starting material was also present. This was used without further purification (note 1).

Workup

  1. customto precipitate
  2. filtrationthe product collected by filtration
  3. washwashed with water
  4. customdried in air at ambient temperature
  5. waitOn standing overnight
  6. customa second crop, 5.8 g was obtained
  7. custom16.55 g, 60%, mp. 252°-254° C., (lit. 255°-259° C.)
  8. customThis was used without further purification (note 1)

Sources & evidence

ORD record
ord-e6f36d4bb0524e1a82475886c5603759
Source dataset
uspto-grants-1993_05
Patent number
US05210209

Reaction notes

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