The preparation of benzimidazoles and imidazopyridines has been achieved under mild
conditions using 2,2,2-trichloroethyl imidates as the acylating agents. The reactions
proceed smoothly in isopropyl alcohol at 70 °C. In cases where the acylation was rapid
but the cyclization proceeded slowly, addition of sodium acetate proved to be beneficial.
For substrates with poor nucleophilicity, modification of the solvent to the more
inert tert-amyl alcohol, which can also achieve higher temperature, allowed for superior reactions.
Key words
benzimidazole - imidazopyridine - imidate - 1,2-diaminoarene - cyclization