The RNA polymerase holoenzyme is a proven target for antibacterial agents. A high- throughput screening program based on this enzyme from Staphylococcus aureus had previously identified a 2-ureidothiophene-3-carboxylate as a low micromolar inhibitor. An investigation of the relationships between the structures of this class of compounds and their inhibitory-and antibacterial activities is described here, leading to a set of potent RNA ...