Novel 1,3,4-oxadiazole thioether and sulfone derivatives bearing a flexible N-heterocyclic moiety: Synthesis,characterization, and anti-microorganism activity

In the search for more efficient and versatile anti-phytopathogen agents, a series of new 1,3,4-oxadiazole thioether/sulfone analogues bearing a flexible N-containing heterocyclic pattern were elaborately prepared, and their bioactivities against plant pathogenic microorganisms were systematically evaluated. Bioassay screening results demonstrated that compounds 32 and 33 significantly inhibited the growth of Xanthomonas oryzae pv. oryzae (Xoo) in vitro (32, EC₅₀ = 5.17 mg L^?1; 33, EC₅₀ = 1.19 mg L^?1), which were significantly surpass commercial bismerthiazol (BT) and thiodiazole copper (TC). Meanwhile, pot experiments confirmed the prospective applications of compound 33 in managing rice bacterial leaf blight and its good safety toward rice plants. Further studies showed that compound 33 interfered with the formation of bacterial biofilms and inhibited bacterial virulence factors. Furthermore, an in vitro antifungal bioassay showed that compound 32 possessed remarkable growth inhibitory activity against Sclerotinia sclerotiorum (S.s., EC₅₀ = 22.16 mg L^?1) and Verticillium dahlia (V.d. EC₅₀ = 32.78 mg L^?1). These results all confirmed that the designed 1,3,4-oxadiazole compounds displayed potential for managing plant microbial diseases through targeting dihydrolipoamide S-succinyltransferase (DLST).     

4-羰基-2-戊烯醛与硫代乙酸加成的研究

以2-甲基-2,5-二甲氧基-2,5-二氢呋喃水解产物与硫代乙酸加成并在不同条件下关环,制得了β-乙酰硫基呋喃、噻吩和毗咯的各种异构产物,提供了按需要制备不同α-甲基-β-巯基呋喃、噻吩和吡咯衍生物的途径。