Synthesis and fungicidal activity of novel 2,5-disubstituted-1,3,4- thiadiazole derivatives containing 5-phenyl-2-furan

Abstract

A series of 2,5-disubstituted-1,3,4-thiadiazoles were synthesized using Lawesson’s reagent by an efficient approach under microwave irradiation in good yields. Their structures were characterized by MS, IR, 1H NMR, 13C NMR, and elemental analysis. Their in vitro and in vivo fungicidal activities revealed that the title compounds exhibited considerable activity against five selected fungi, especially to Phytophthora infestans. In order to illustrate the mechanism of title compounds against P. infestans, scanning electron micrographs (SEM) and transmission electron micrographs (TEM) were applied. The morphological and ultrastructural studies demonstrated that compound I18 led to swelling of hyphae, thickening and proliferating multilayer cell walls, excessive septation and accumulation of dense bodies. The bioassay results indicated compound I18 might act on cell wall biosynthesis, and blocked the nutrition transportation and led to cells senescence and death. Meanwhile, compound I18 had broad fungicidal activity against other twenty different kinds of fungi. These results suggested that title compounds were eligible to be development candidates and compound I18 as a promising lead compound was worthy to be further discovery, especially against P. infestans.

Inhibitory effect ofBacillus subtilisWL-2 and its IturinA lipopeptides againstPhytophthora infestans

“…12A-d) were formed in the mycelia. Much of the changes in mycelial appearance are probably due to the damage of the internal cell structure(53, 54). Next, our TEM results showed that the inhibited cell membranes were disrupted (Fig.…”

“…Meanwhile, mycelia were fixed using 2.5% (v/v) glutaraldehyde (Solarbio, Beijing, China) for 24 h and dehydrated for 30 min in every step using aqueous ethanol solutions (30, 50, 70, and 90%, v/v). Then, morphological and surface changes were observed using an SEM system (JSM-7500F, JEOL, JAPAN)(53). A TEM (JEM-2100F, JEOL, JAPAN) system(53, 54) was also adopted to evaluate the structural characteristics of inhibited mycelia.…”

“…Then, morphological and surface changes were observed using an SEM system (JSM-7500F, JEOL, JAPAN)(53). A TEM (JEM-2100F, JEOL, JAPAN) system(53, 54) was also adopted to evaluate the structural characteristics of inhibited mycelia. Similar to above, 2.5% (v/v) glutaraldehyde was used to fix damaged mycelia, 1% (v/v) osmium tetroxide was used to fix mycelia at 20°C for 20 min, and finally, a microtome (YD335, Leica, Germany) was used to prepare thick specimens (70 nm) for TEM observation.…”

Synthesis, Biological Evaluation and Molecular Modeling Studies of New Oxadiazole-Stilbene Hybrids against Phytopathogenic Fungi

“…The in vitro fungicidal activity against B. cinerea was tested using the mycelial growth inhibition method 48 . The tested compounds were dissolved in dimethyl sulfoxide (DMSO) and diluted with distilled water containing 0.05% Tween 80 to prepare the 10 mg/mL stock solution.…”

QSAR and molecular docking studies of novel 2,5-distributed-1,3,4-thiadiazole derivatives containing 5-phenyl-2-furan as fungicides against Phythophthora infestans

“…Thirty-two derivatives of 2,5-disubstituted-1,3,4-thiadiazole derivatives containing 5-phenyl-2-furan used in this work were taken from the literature [8]. The activity of the compounds were reported in EC50 (g/L) values, which were converted to pEC50 (pEC50 = − log1/EC50).…”