Microwave-Enhanced Solid-Phase Synthesis of N,N′-Linked Aliphatic Oligoureas and Related Hybrids

A practical and efficient microwave-assisted solid-phase method for the synthesis of N,N'-linked oligoureas and related amide/urea hybrid oligomers, featuring the use of succinimidyl (2-azido-2-substituted ethyl) carbamate monomers, is reported. The rate enhancement of urea formation under microwave irradiation combined with the mild conditions of the phosphine-based azide reduction makes this approach very effective for routine synthesis of oligoureas and possibly for library production.