Exploiting the CNC Side Chain in Heterocyclic Rearrangements: Synthesis of 4(5)-Acylamino-imidazoles

A new variation on the Boulton−Katritzky reaction is reported, namely, involving use of a CNC side chain. A novel Montmorillonite-K10 catalyzed nonreductive transamination of a 3-benzoyl-1,2,4-oxadiazole afforded a 3-(α-aminobenzyl)-1,2,4-oxadiazole, which was condensed with benzaldehydes to afford the corresponding imines. In the presence of strong base, these imines underwent Boulton−Katritzky-type rearrangement to afford novel 4(5)-acylaminoimidazoles.