Function-Oriented Synthesis of Simplified Caprazamycins: Discovery of Oxazolidine-Containing Uridine Derivatives as Antibacterial Agents against Drug-Resistant Bacteria

The rational simplification of the caprazamycin (CPZ) class of nucleoside natural products was carried out to address their molecular complexity. First, analogues 6-8, where the diazepanone ring of the CPZ was removed and a lipophilic side chain was attached to either the C-7' or N(6') atom, were used to investigate the conformation activity relationship. On the basis of this relationship, we designed the oxazolidine-containing uridine derivatives 18-21 by restricting the conformation of 6-8. As a result, the 'Bu ester derivatives 20 were found to be the most active against a range of bacterial strains containing VRE with a potency similar to that of the parent CPZs. This study provides a novel strategy for the development of a new type of antibacterial agent effective against drug-resistant bacteria.