Total Synthesis of the Anti Methicillin-Resistant <i>Staphylococcus aureus</i> Peptide Antibiotics TAN-1057A-D YuanChenguang WilliamsRobert M. 1997 TAN-1057A−D, dipeptides isolated from bacteria <i>Flexibacter</i> sp. PK-74 and PK-176, are new antibiotics with potent antibacterial activity against methicillin-resistant <i>Staphylococcus aureus</i>. We describe, in detail, the total synthesis of TAN-1057A−D by a convergent route featuring a new method to construct the cyclic amidinourea functional group.