Synthesis and Antibacterial Evaluation of N-phenylacetamide Derivatives Containing 4-Arylthiazole Moieties

A series of newN-phenylacetamide derivatives containing 4-arylthiazole moieties was designed and synthesized by introducing the thiazole moiety into the amide scaffold. The structures of the target compounds were confirmed by1H-NMR,13C-NMR and HRMS. Their in vitro antibacterial activities were evaluated against three kinds of bacteria—Xanthomonas oryzaepv.Oryzae(Xoo),Xanthomonas axonopodispv.Citri(Xac) andX.oryzaepv. oryzicola(Xoc)—showing promising results. The minimum 50% effective concentration (EC50) value ofN-(4-((4-(4-fluoro-phenyl)thiazol-2-yl)amino)phenyl)acetamide (A1) is 156.7 µM, which is superior to bismerthiazol (230.5 µM) and thiodiazole copper (545.2 µM). A scanning electron microscopy (SEM) investigation has confirmed that compoundA1could cause cell membrane rupture ofXoo. In addition, the nematicidal activity of the compounds againstMeloidogyne incognita(M. incognita) was also tested, and compoundA23displayed excellent nematicidal activity, with mortality of 100% and 53.2% at 500 μg/mL and 100 μg/mL after 24 h of treatment, respectively. The preliminary structure-activity relationship (SAR) studies of these compounds are also briefly described. These results demonstrated that phenylacetamide derivatives may be considered as potential leads in the design of antibacterial agents.Keywords:synthesis;thiazole;nematicidal activity;antibacterial activity;structure-activity relationship