Design, synthesis and antibacterial evaluation of novel AHL analogues

Two series of novel AHL analogues were designed, synthesized and evaluated for antibacterial activity under cell membrane conditions in vitro. Analogues 4a-c and 4g-m presented potent activity against Gram-positive bacteria. Especially the analogue 4l exerted the most potent inhibition against Bacillus subtilis with MIC50 value of 1.443 μg/ml. To our surprise, analogues 6a-c and 6g showed weak inhibition against Gram-negative bacteria with MIC50 values ranging from 17.589 to 67.840 μg/ml. This was the first report about synthesis and antibacterial evaluation in vitro of AHL analogues containing dithioester linkage.