SOLID-PHASE SYNTHESIS OF BENZIMIDAZOLES

An efficient solid phase synthesis of benzimidazoles is described. Pol ymer bound o-fluoronitroaromatic compound 2 was treated with an amine to give o-nitroaniline derivative 3, Reduction of 3 with NaBH4-Cu(acac )(2) followed by cyclization with an aryl imidate and cleavage with TF A gave 5. A library of benzimidazoles has been prepared in three steps in 70-95 % crude yield and 70-98 % purity. Final purified yield range d from 54-93 %. Extension of this synthesis to the split/pool method i s also reported. Copyright (C) 1996 Elsevier Science Ltd