Synthesis of a meso -Oxa-Diaminopimelic Acid Containing Peptidoglycan Pentapeptide and Coupling to the GlcNAc- anhydro -MurNAc Disaccharide.

The syntheses of peptidoglycan (PG)-derived peptides containing meso -diaminopimelic acid ( meso -Dap) are typically quite lengthy due to the need to prepare orthogonally protected meso -Dap. In this work, the preparation of the PG pentapeptide containing the isosteric analog meso -oxa-Dap is described. The synthesis relies on the ring opening of a peptide embedded aziridine via the attack of a serine residue. The pentapeptide was attached to a GlcNAc-anhydro-MurNAc disaccharide, to produce a putative substrate for the AmpG pore protein.