Synthesis and Antibacterial Evaluation of Novel 1,3,4-Oxadiazole Derivatives Containing Sulfonate/Carboxylate Moiety

Abstract

In order to discover new lead compounds with high antibacterial activity, a series of new derivatives were designed and synthesized by introducing a sulfonate or carboxylate moiety into the 1,3,4-oxadiazole structure. Antibacterial activity against two phytopathogens, Xanthomonas oryzae pv. oryzae (Xoo) and Xanthomonas axonopodis pv. citri (Xac), was assayed in vitro. The preliminary results indicated that ten compounds including 4a-1-4a-4 and 4a-11-4a-16 had good antibacterial activity against Xoo, with EC50 values ranging from 50.1-112.5 µM, which was better than those of Bismerthiazol (253.5 µM) and Thiodiazole copper (467.4 µM). Meanwhile, 4a-1, 4a-2, 4a-3 and 4a-4 demonstrated good inhibitory effect against Xanthomonas axonopodis pv. citri with EC50 values around 95.8-155.2 µM which were better than those of bismerthiazol (274.3 µM) and thiodiazole copper (406.3 µM). In addition, in vivo protection activity of compound 4a-2 and 4a-3 against rice bacterial leaf blight was 68.6% and 62.3%, respectively, which were better than bismerthiazol (49.6%) and thiodiazole copper (42.2%). Curative activity of compound 4a-2 and 4a-3 against rice bacterial leaf blight was 62.3% and 56.0%, which were better than bismerthiazol (42.9%) and thiodiazole copper (36.1%). Through scanning electron microscopy (SEM) analysis, it was observed that compound 4a-2 caused the cell membrane of Xanthomonas oryzae pv. oryzae ruptured or deformed. The present results indicated novel derivatives of 5-phenyl sulfonate methyl 1,3,4-oxadiazole might be potential antibacterial agents.

Design, Synthesis and Biological Activity of Myricetin Derivatives Containing 1,2,4-Triazolo[3,4-b]-1,3,4-thiadiazole

“…中间体 1、2 和 3 参照文献合成 [22][23] , 中间体 4 和 5 参照文献合成 [24][25] 对目标化合物的抗 TMV 活性测试采用半叶枯斑 法 [27][28] , 将心叶烟两边叶片撒上金刚砂, 用排笔刷蘸取 500 μg/mL 的 TMV 病毒, 均匀的刷在两边的烟叶上, 0.5 h 后, 用毛笔刷蘸取待测化合物溶液(500 μg/mL), 均匀 地涂抹在烟叶的右边. 晾干后, 移至 28 ℃环境中培养 2～3 d, 叶片出现明显的斑点后, 记录左右两边叶片上 的斑点数, 利用公式计算抑制率.…”

Novel 1,3,4‐oxadiazole sulfonate/carboxylate flavonoid derivatives: synthesis and biological activity

“…Procedures for the preparation of intermediates 1-4 are provided in the references. [37][38][39] 2.2.2 General procedures for preparing target compounds B1, B2, C1-C20 and D1-D10 Intermediate 2 (2.4 mmol), K 2 CO 3 (3 mmol) and 20 ml dimethylformamide (DMF) were put into a flask. Intermediate 4 (2 mmol) was added after 20 min.…”