Synthesis and Biological Activity Evaluation of 1,2,3-Thiadiazole Derivatives as Potential Elicitors with Highly Systemic Acquired Resistance

Abstract

Elicitors provide a broad spectrum of systemic acquired resistance by altering the physical and physiological status of the host plants and, therefore, are among the most successful directions in modern pesticide development for plant protection. To develop a novel elicitor with highly systemic acquired resistance, two series of thiazole- and oxadiazole-containing thiadiazole derivatives were rationally designed and synthesized according to the principle of combination of bioactive substructures in this work. Their structures were characterized by (1)H nuclear magnetic resonance (NMR), infrared (IR), high-resolution mass spectrometry (HRMS), or elemental analysis. Their potential systemic acquired resistance as an elicitor was also evaluated; bioassay results indicated that, among the 23 compounds synthesized, three compounds, 10a, 10d, and 12b, displayed better systemic acquired resistance than the positive control, tiadinil, a commercialized 1,2,3-thiadiazole-based elicitor. In addition, three other compounds, 10f, 12c, and 12j, exhibited a certain degree of fungus growth inhibition in vitro or in vivo. Our results demonstrated that, in combination of bioactive substructures is an interesting exploration for novel pesticide development, thiazole- and oxadiazole-containing thiadiazole derivatives are potential elicitors with good systemic acquired resistance.

Synthesis of tetrazole containing 1,2,3-thiadiazole derivatives via U-4CR and their anti-TMV activity

“…The starting material, ethyl 4-methyl-1,2,3-thiadiazole-5-carboxylate 1, was prepared according to Ref. [9]. Cyclohexyl isocyanide was synthesized according to Ref.…”

“…Successful commercialization of some 1,2,3-thiadiazoles such as tiadinil (TDL) [7] and acibenzolar-S-methyl (BTH) [8] as elicitors accelerated the studies of their synthesis and systemic acquired resistance (SAR). [9][10][11] Tetrazoles and their derivatives have been reported as antibacterial [12], antiviral [13], herbicidal [14], anti-inflammatory [15] antitumor [16], analgesic [17], and antiproliferative [18] agents. There are many reports about each of the two heterocyclics, but the combination of 1,2,3-thiadiazole ring with tetrazole ring in one molecule is seldom reported both in chemistry and their biological activity studies.…”

Oxidative cyclization of N-alkyl-2-arylhydrazonothioacetamides

“…In the case of substrates with the alkyl substituent in the 5 imino group, the corresponding 2,5 dihydro 1,2,3 thiadiazoles are so stable that even in the presence of strong bases (for example, KOH) the transformation involves only side substituents, whereas the heterocyclic fragment remains unchanged. 4 Si as an internal standard. IR spectra were mea sured on a Bruker Alpha FTIR spectrometer (Frustrated Total Internal Reflection, ZnSe).…”

Synthesis, structure, and fungicidal activity of triorganotin (4H‐1,2,4‐triazol‐4‐yl)benzoates

“…Preliminary in vitro tests for fungicidal activity of all compounds have been carried out by the fungi growth inhibition method [26]. The data are summarized in Table 2, which indicate that all compounds involving in complexes 3-12 as well as the free acids 1 and 2 display high activities to Botrytis cinere.…”