Design, synthesis, crystal structure, and antimicrobial activities of new quinazoline derivatives containing both the sulfonate ester and piperidinylamide moieties.

BACKGROUND: To discover more efficient antimicrobial agents in agriculture, a series of new quinazoline derivatives bearing both sulfonate ester and piperidine‐4‐carboxamide moieties were synthesized and assessed for their antimicrobial effects. RESULTS: All of the target compounds were fully characterized by proton (1H) nuclear magnetic resonance (NMR), carbon‐13 (13C) NMR, and high‐resolution mass spectroscopy (HRMS), and compound III‐6 containing a 3‐bromophenyl substituent was clearly confirmed via single‐crystal X‐ray diffraction analysis. The bioassay results indicated that some compounds displayed noticeable inhibitory effects in vitro against Xanthomonas oryzae pv. oryzicola (Xoc). Further measurements of median effective concentration (EC50) values showed that compound III‐17 bearing a 4‐methoxyphenyl group had the best anti‐Xoc efficacy (EC50 = 12.4 μg mL−1), far better than the commercialized bismerthiazol (77.5 μg mL−1). Moreover, this compound also demonstrated good protection and curative activities in vivo against rice bacterial leaf streak caused by Xoc. CONCLUSION: Compound III‐17 had a good potential for further development as a new bactericide for controlling Xoc. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]