β-Lactam antibiotic resistance caused by metallo-β-lactamases (MBLs) is an emerging health threat to humans. These zinc-dependent lactamases are capable of hydrolysing a wide spectrum of β-lactam antibiotics. No clinical inhibitors of MBLs are available.1 The clinically-relevant IMP-1 MBL is a suitable enzyme target for undertaking inhibitory activity studies.2 As part of our on-going work to develop novel MBL inhibitors we have identified a 2-amino-4-cyanopyrrole (1) as a competitive IMP-1 inhibitor with a Ki value of 21 μM.3 Synthetic modification of pyrrole (1) led to the identification of a series of 2-N-acyl substituted pyrrole derivatives which exhibited improved IMP-1 inhibitory activities with some Ki values as low as 1.24 μM.
