A Novel Strategy of Ugi-4CR/Huisgen 1,3-Dipolar Synthesis of 1H-1,2,3-Triazole-Modified Peptidoimetics

In this protocol, we report a novel approach for the synthesis of a new class of heterocyclic 1H-1,2,3-triazole-modified peptidoimetic compounds. The process consists of an Ugi four-component condensation reaction of amines, an isocyanide, an aldehyde and acids followed by a Huisgen 1,3-dipolar cycloaddition reaction with an azide group in the presence of a catalytic amount of CuSO4.5H2O/sodium ascorbate. The copper-catalyzed Huisgen cycloaddition reactions provide such a general synthetic method, with the resulting 1,2,3-triazoles being good peptide bond mimics. This protocol was highly efficient for structurally diverse heterocyclic molecules containing an active aldehyde group and will find applications in combinatorial chemistry, diversity-oriented synthesis, and drug discovery.