Synthesis and larvicidal activity against Culex pipiens pallens of new triazole derivatives of phrymarolin from Phryma leptostachya L

Insecticidal Activity of Four Lignans Isolated from Phryma leptostachya

A new lignan (T4) and three known lignans (T1, T2, and T3) were isolated from the methanol extract of the roots of Phryma leptostachya using bioassay-guided method, and their structures were identified as phrymarolin I (T1), II (T2), haedoxan A (T3), and methyl 4-((6a-acetoxy-4-(6-methoxybenzo[d][1,3]dioxol-5-yl)tetrahydro-1H,3H-furo[3,4-c]furan-1-yl)oxy)-1-hydroxy-2,2-dimethoxy-5-oxocyclopent-3-ene-1-carboxylate (T4) byNMR and ESI-MS spectral data. Bioassay results revealed that haedoxan A exhibited remarkably high insecticidal activity against Mythimna separata with a stomach toxicity LC₅₀ value of 17.06 mg/L and a topical toxicity LC₅₀ value of 1123.14 mg/L at 24 h, respectively. Phrymarolin I and compound T4 also showed some stomach toxicity against M. separata with KD₅₀ values of 3450.21 mg/L at 4 h and 2807.10 mg/L at 8 h, respectively. In addition, phrymarolin I and haedoxan A exhibited some stomach toxicity against Plutella xylostella with an LC₅₀ value of 1432.05 and 857.28 mg/L at 48 h, respectively. In conclusion, this study demonstrated that lignans from P. leptostachya are promising as a novel class of insecticides or insecticide lead compounds for developing botanical pesticides.

Synthesis, photophysical, antibacterial and larvicidal studies on triazolophanes with 5-nitro isophthalate functionality at the intraannular position

1 : 1 and 2 : 2 oligomeric triazolophanes have been successfully synthesized from the corresponding propargylic esters and various aryl alkyl azides.

Synthesis and Larvicidal Activity of Phrymarolin Derivatives against Culex Pipiens Pallens

Twenty-eight new phrymarolin derivatives, including twenty-one ethers, six esters and a dehydroxy phrymarolin, were prepared from phrymarolin I and the structures of all the derivatives were confirmed by 1H NMR and 13C NMR spectroscopic and MS data analyses. Larvicidal activities of these phrymarolin analogues were assayed against 4th instar larvae of Culex pipiens pallens. The ester derivatives of phrymarolin showed lower larvicidal activity than phrymarolin I, but some of the ether derivatives and dehydroxy phrymarolin showed much higher activity. Two ether derivatives, 1–18 and 1–19, showed significant larvicidal activity with LC50 values of 1.89 and 7.78 mg/L, respectively.

Microwave assistant synthesis, antifungal activity and DFT theoretical study of some novel 1,2,4-triazole derivatives containing pyridine moiety

In order to investigate the biological activity of novel 1,2,4-triazole compounds, seventeen novel 1,2,4-triazole derivatives containing pyridine moiety were synthesized under microwave assistant condition by multi-step reactions. The structures were characterized by ¹H NMR, MS and elemental analyses. The target compounds were evaluated for their fungicidal activities against Stemphylium lycopersici (Enjoji) Yamamoto, Fusarium oxysporum. sp. cucumebrium, and Botrytis cinerea in vivo, and the results indicated that some of the title compounds displayed excellent fungicidal activities. Theoretical calculation of the title compound was carried out with B3LYP/6-31G (d,p). The full geometry optimization was carried out using 6-31G (d,p) basis set, and the frontier orbital energy, atomic net charges were discussed, and the structure-activity relationship was also studied.