Synthesis and Pesticidal Activities of 5-(2-Cyclopropylaminopyrimidin-4-yl)-4-(thiophenyl)thiazole Derivatives

Abstract

Pesticidal activities of 4-[5-(2-cyclopropylaminopyrimidin-4-yl)-4-(4-chloro-2-fluoro-phenyl)thiazol-2-yl]-1-methylpiperidine, designated as Comp I, have been determined against a mosquito larva, Culex pipiens pallens, and a phytopathogenic fungus, Phytophthora capsici. Comp I was used as the leading compound in this study. The compounds were synthesized by reacting them with two functional groups, 3-thiophenyl and 2-thiophenyl groups, instead of 4-chloro-2-fluorophenyl group in Comp I. Other functional groups such as 2-aminothiazole, 2-(1-methylpiperazin-4-yl)thiazole, and 2-(piperazin-4-yl)thiazole were also introduced instead of 2-methylpiperidin-4-yl-thiazole of Comp I. Compounds designated as XIII-6∼XV-7 were newly synthesized and their structures were confirmed by 1 H-and 13 C-NMR spectroscopy. Mosquito larvicidal activities of all the synthesized compounds against C. pipiens pallens were examined and Comp I among them showed the strongest larvicidal activity as 0.513 mM of LC 50 value. The fungicidal activities of all the synthesized compounds against P. capsici were examined using the whole plant method. Among the XIII-6∼XV-7 chemicals, 5-(2-cyclopropylaminopyrimidin-4-yl)-4-(thiophen-2-yl)thiazol-2-amine (VIII-6) showed the most potent antifungal activity in vivo. While the EC 50 value of the commercial fungicide dimethomorph was 4.26 M, EC 50 of VIII-6 was 0.94 M. Therefore, thiazole derivatives can be considered as viable candidates for the control of mosquito larvae and plant diseases.

Advances in the green synthesis and agrichemical applications of oxathiapiprolin derivatives

“…Subsequently, when the terminal group was replaced and the remaining thiazole and piperidine rings in the oxathiapiprolin molecule unchanged (e.g., compounds 6 , 7 , 8 , and 9 ), their fungicidal activities have not been significantly improved, instead of certain insecticidal activities ( Zhu et al, 2016 ; Ding et al, 2019a ; Ding et al, 2019c ; Ding et al, 2020 ). However, Choi et al (2015) reported a novel compound 10 with high fungicidal and insecticidal activities through the modification of the thiazole ring in 2015, with the EC 50 value of 0.98 μM against P. capsici and the LC 50 value of 0.513 μM against Cx. p. pallens .…”