Carbon Dioxide → 2-Benzimidazolecarboxylic acid

Participants

Reaction Conditions

Reaction Steps

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.).

Provenance & Evidence