title: An efficient procedure for the preparation of 4-substituted 5-aminoimidazoles.
abstract: The preparation of O-methylimidates from alpha-aminonitriles and their subsequent co-cyclization with primary amines to afford 4-substituted 5-aminoimidazoles was studied. It was found that the mildly acidic pyridinium p-toluenesulfonate efficiently catalyzed each stage of the reaction sequence: (a) the formation of the O-methylimidates, (b) their co-cyclization with a variety of primary amines, and (c) certain derivatizations of the resultant heterocycles. The developed reaction conditions tolerate a wide variety of alpha-aminonitriles and primary amine co-reactants. Thus, it is possible to easily prepare a diverse array of substituted heterocyclic compounds in good yield. The requisite alpha-aminonitriles were synthesized either from amino acids or by phase-transfer alkylation of a glycine anion equivalent. The unstable free 5-aminoimidazoles were normally protected in situ to provide derivatives (methyl imidates or N,N-dimethylamidines) that were amenable to characterization.
authors.affiliation: Department of Chemistry, University of California, Berkeley, California 94720, USA. mark_mcl@uclink.berkeley.edu
authors.forename: Mark
authors.initials: M
authors.lastname: McLaughlin
authors.forename: Rafat M
authors.initials: RM
authors.lastname: Mohareb
authors.forename: Henry
authors.initials: H
authors.lastname: Rapoport