Boric Acid-Catalyzed Direct Condensation of Carboxylic Acids with Benzene-1,2-diamine into Benzimidazoles
作者:Nenad Maraš、Marijan Kočevar
DOI:10.1002/hlca.201100064
日期:2011.10
applicability of boric acid catalysis for the direct condensation of carboxylicacids with benzene‐1,2‐diamine to give 2‐substituted benzimidazoles was investigated. It was found that catalytic amounts (5–10 mol‐%) of boric acid efficiently promote the cyclocondensation of aliphatic carboxylicacids in refluxing toluene. In addition, the relatively neutral conditions allow the use of acid‐sensitive substrates