Carbon Dioxide → 2-Benzimidazolecarboxylic acid

HRID 1197169Notes

Reaction equation

HRID 1197169 reaction equation
[N:1]1[C:5]2[CH:6]=[CH:7][CH:8]=[CH:9][C:4]=2[NH:3][CH:2]=1.[C:10]([O-])([O-:12])=[O:11].[K+].[K+].C(=O)=O.Cl>O>[N:1]1[C:5]2[CH:6]=[CH:7][CH:8]=[CH:9][C:4]=2[NH:3][C:2]=1[C:10]([OH:12])=[O:11]

Participants

6

Reactant 4

HCID 280Carbon DioxideHCID 313Hydrochloric AcidHCID 5798BenzimidazoleHCID 11430Potassium Carbonate

Product 1

HCID 2332402-Benzimidazolecarboxylic acidYield 73%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
250 °C

Procedure

A mixture of 118 g (1 mol) of benzimidazole, g (2 mol) of K2CO3 and 400 ml of liquid carbon dioxide was stirred in an autoclave at 250° C. under autogenous pressure for 10 hours. The solid output was pulverized, suspended in 2.5 L of water and brought to pH 3-4 with concentrated hydrochloric acid while being cooled with ice. The resulting precipitate was filtered off and recrystallized from water to give 118 g (73%) of benzimidazole-2-carboxylic acid (Compound No. 4); mp. 170° C. (dec.).

Workup

  1. temperaturewhile being cooled with ice
  2. filtrationThe resulting precipitate was filtered off
  3. customrecrystallized from water

Sources & evidence

ORD record
ord-77ba19f607d74d039c7c3bcbd7fdb3ea
Source dataset
uspto-grants-1992_05
Patent number
US05117004

Reaction notes

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