Abstract Novel 4 ″-O-carbamoyl erythromycin-A derivatives were designed, synthesized, and evaluated for their in-vitro antibacterial activities. All of the 4 ″-O-carbamoyl derivatives showed excellent activity against erythromycin-susceptible Staphylococcus aureus ATCC25923, Streptococcus pyogenes, and Streptococcus pneumoniae ATCC49619. Most of the 4 ″-O-arylalkylcarbamoyl derivatives displayed potent activity against erythromycin ...