Synthesis of 1,2,3-Thiadiazole and Thiazole-Based Strobilurins as Potent Fungicide Candidates

Abstract

Strobilurin fungicides play a crucial role in protecting plants against different pathogens and securing food supplies. A series of 1,2,3-thiadiazole and thiazole-based strobilurins were rationally designed, synthesized, characterized, and tested against various fungi. Introduction of 1,2,3-thiadiazole greatly improved the fungicidal activity of the target molecules. Compounds 8a, 8c, 8d, and 10i exhibited a relatively broad spectrum of fungicidal activity. Compound 8a showed excellent activities against Gibberella zeae, Sclerotinia sclerotiorum, and Rhizoctonia cerealis with median effective concentrations (EC) of 2.68, 0.44, and 0.01 μg/mL, respectively; it was much more active than positive controls enestroburin, kresoxim-methyl, and azoxystrobin with EC between 0.06 and 15.12 μg/mL. Comparable or better fungicidal efficacy of compound 8a compared with azoxystrobin and trifloxystrobin against Sphaerotheca fuliginea and Pseudoperonspera cubensis was validated in cucumber fields at the same application dosages. Therefore, compound 8a is a promising fungicidal candidate worthy of further development.

Design, synthesis and fungicidal activity of isothiazole–thiazole derivatives

“…17 Novel fungicide development is one of the important directions and measures for fungicide resistance management. 20 On the basis of our former ndings, 4,5,[21][22][23] to continue our aim of nding novel highly anti-fungal active compounds with novel modes of action and without resistance risks, 4 types of novel target molecules were designed and synthesized for fungicidal activity and systemic acquired resistance evaluation based on PcORP1 as the target and N and S containing vemembered heterocycles as bioactive substructures by the combination of bioactive substructures of plant elicitor isotianil and fungicide oxathiapiprolin according to the active compound derivatization method 24 (Fig. 1 and Table 1).…”

Discovery of a new fungicide by screening triazole sulfonylhydrazone derivatives and its downy mildew inhibition in cucumber

“…The statistical analysis of control effects was established via variance analysis and reverse arcsine transformation. In addition, the significant difference was compared by LRS method between each treatment …”

Synthesis and antifungal activities of novel thiophene‐based stilbene derivatives bearing an 1,3,4‐oxadiazole unit

“…Heterocyclic rings are important chemical scaffolds in the search for novel pesticides. Approximately 70% of pharmaceuticals and agrochemicals contain at least one heterocyclic moiety, and as one of the most important, the 1,3,4‐oxadiazole ring is reported to possess a wide variety of biological activities, including antibacterial, antifungal, antiviral, insecticidal and herbicidal . For instance, Guimarães et al .…”

“…Heterocyclic rings are important chemical scaffolds in the search for novel pesticides. Approximately 70% of pharmaceuticals and agrochemicals contain at least one heterocyclic moiety, 18 and as one of the most important, the 1,3,4-oxadiazole ring is reported to possess a wide variety of biological activities, including antibacterial, [19][20][21] antifungal, 22,23 antiviral, 24 insecticidal 25 and herbicidal. 26 For instance, Guimarães et al reported that introduction of a 1,3,4-oxadiazole ring into target compounds could change their polarity, binding affinity with their receptor and flexibility, effectively enhancing their bioactivity.…”