A General and Facile Synthetic Approach to Nα-Boc Ureidoalanine Derivatives

We report a new and facile synthetic approach to N α -Boc ureidoalanine derivatives from commercially available Boc-L-aspartic acid. Not only N'-substituted but also N',N'-disubstituted ureidoalanine derivatives may be obtained by this method. The key aspect of this method is the employment of a 5-oxazolidinone to provide proper protection of the α-nitrogen of L-aspartic acid. This ensures successful obtainment of the corresponding isocyanate by a Curtius rearrangement.