The synthesis of new 1β-methylcarbapenems 1a–d bearing aminopyrimidinylthioether moiety at C-5 position of pyrrolidine ring and their antibacterial activities are described. All the compounds exhibited potent antibacterial activity. Of these carbapenems, 1d showed the best combination of antibacterial activity and stability to dehydropeptidase-I (DHP-I).
