Formic Acid → 4-Bromo-1H-benzimidazole

HRID 735362Notes

Reaction equation

HRID 735362 reaction equation
[NH2:1][C:2]1[CH:7]=[CH:6][CH:5]=[C:4]([Br:8])[C:3]=1[NH2:9].[OH-].[Na+].[CH:12](O)=O>>[Br:8][C:4]1[C:3]2[N:9]=[CH:12][NH:1][C:2]=2[CH:7]=[CH:6][CH:5]=1

Participants

4

Reactant 3

HCID 284Formic AcidHCID 14798Sodium HydroxideHCID 124898393-Bromobenzene-1,2-diamine

Product 1

HCID 112525844-Bromo-1H-benzimidazole

Procedure

A solution of 1,2-diamino-3-bromobenzene (2.00 g, 10.7 mmol) in formic acid (10 mL) was stirred at 100° C. for 1 hour. The pH of the mixture was adjusted to 14 by the addition of 4 M sodium hydroxide solution, precipitating the product as a solid. This was separated by filtration, washed with water and air-dried affording the product as an off-white solid. A further crop of equally pure material precipitated from the filtrate upon standing at room temperature for a few days. Total yield=1.98 g, 94%. 1H NMR (500 MHz, d6-DMSO): δ 12.83 (1H, s), 8.30 (1H, s), 7.58 (1H, d, J=7.9 Hz), 7.41 (1H, d, J=7.1 Hz), 7.14 (1H, t, J=7.8 Hz); m/z (ES+) 197, 199 [MH+].

Workup

  1. customprecipitating the product as a solid
  2. customThis was separated by filtration
  3. washwashed with water
  4. customair-dried

Sources & evidence

ORD record
ord-7f58adb017624216b9a0792c45290795
Source dataset
uspto-grants-2009_09
Patent number
US07592456B2

Reaction notes

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