ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Potent antibacterial agents: pyridinium-functionalized amphiphiles bearing 1,3,4-oxadiazole scaffolds

Pei-Yi Wang, Lei Zhou, Jian Zhou, He-Shu Fang, Zhi-Bing Wu, Wei Xue, Bao-An Song, and Song Yang

State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemicals, Guizhou University, Guiyang, China

E-mail: songbaoan22@yahoo.com

Abstract: Through tuning and optimizing the phenyl substituents and alkyl length, a series of pyridinium-functionalized amphiphiles possessing potent antibacterial activity toward three types of plant pathogenic bacteria were obtained. Investigations on the inhibition effect of substituents on the phenyl ring towards the bioactivity suggested that the substitutional group was not the crucial factor for the bioactivity. In comparison, the antibacterial effects could be significantly enhanced with increasing the length of alkyl chains. Among these amphiphiles, 6c, 6f, 6h, 6i, 6k, 6l, 6n, and 6q exhibited remarkable inhibition activities against the three pathogenic bacteria with the half-maximal effective concentration (EC₅₀) values within 0.128–1.98 µg/mL. Furthermore, the minimum EC₅₀ values against the pathogens Xanthomonas oryzae pv. oryzae and Xanthomonas axonopodis pv. citri could reach to 0.128 and 0.403 µg/mL, respectively, which were decreased about four times than those of our previous results. Given their simple synthesis and biocidal antibacterial activity, this kind of amphiphiles could be developed as promising bactericides against plant bacterial diseases.

Keywords: Pyridinium; Amphiphile; 1,3,4-Oxadiazole; Substituents; Antibacterial

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-016-0021-7

Chemical Papers 71 (6) 1013–1018 (2017)