Helvetica Chimica Acta

Boric Acid??Catalyzed Direct Condensation of Carboxylic Acids with Benzene??1, 2??diamine into Benzimidazoles

N Maraš, M Kočevar

Index: Maras, Nenad; Kocevar, Marijan Helvetica Chimica Acta, 2011 , vol. 94, # 10 p. 1860 - 1874

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Citation Number: 12

Abstract

Abstract The applicability of boric acid catalysis for the direct condensation of carboxylic acids 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 carboxylic acids in refluxing toluene. In addition, the relatively neutral conditions allow the use of acid-sensitive substrates and give rise to specific ...