Synthesis and Antibacterial Activity of Acylides (3-<i>O</i>-Acyl-erythromycin Derivatives):  A Novel Class of Macrolide Antibiotics

Introduction of an acyl group to the 3-<i>O</i>-position of erythromycin A derivatives instead of l-cladinose led to a novel class of macrolide antibiotics that we named “acylides”. The 3-<i>O</i>-nitrophenylacetyl derivative TEA0777 showed significantly potent activity against not only erythromycin-susceptible Gram-positive pathogens but also inducibly macrolides-lincosamides-streptogramin B (MLS<sub>B</sub>)-resistant <i>Staphylococcus aureus</i> and efflux-resistant <i>Streptococcus pneumoniae</i>. These results indicated that acylides have potential as next-generation macrolide antibiotics.