Design, Synthesis and Evaluation of Novel Isoxazolines/Oxime Sulfonates of 2′(2′,6′)-(Di)Chloropodophyllotoxins as Insecticidal Agents

Abstract

A series of 2′(2′,6′)-(di)halogeno-isoxazolopodophyllic acids-based esters, and oxime sulfonates of 2′(2′,6′)-(di)halogenopodophyllones were prepared by structural modifications of podophyllotoxin as insecticidal agents against Mythimna separata Walker. It was found that when 2′(2′,6′)-(di)halogenopodophyllones or 2′(2′,6′)-(di)chloropicropodophyllones reacted with hydroxylamine hydrochloride, the desired products were related with the configuration of their lactones. Three key single-crystal structures of Ie, IIe and IIIb were determined by X-ray diffraction. Especially compounds IIc and Vc showed the highest insecticidal activity. Moreover, some interesting results of structure-insecticidal activity relationships of tested compounds were also observed.

TiO2-Based Nanoheterostructures for Promoting Gas Sensitivity Performance: Designs, Developments, and Prospects

“…During the typical process, a glutinous precursor solution is injected through a thin spinneret and then is stretched to form ultralong nanofibers; finally annealing the as-prepared samples at appropriate temperature can produce very highly crystalline nanofibers. In recent years, our group has successfully synthesized TiO 2 /Ag 0.35 V 2 O 5 branched nanoheterostructures using a simple one-step electrospinning method [ 95 , 96 ]. The synthesis process of TiO 2 /Ag 0.35 V 2 O 5 nanoheterostructures and characterization of the nanoheterostructures are presented in Figure 7 .…”

“…According to Equation (3), R a /R g is proportional to exp(Δ qΦ ), thus the notable changes of energy barrier height can cause remarkable changes of the resistivity and superior enhancement of sensing properties for heterojunctions. For instance, Fe 2 O 3 /TiO 2 tube-like nanoheterostructures [ 107 ] and TiO 2 /Ag 0.35 V 2 O 5 branched nanoheterostructures [ 95 ] based sensors exhibited improved ethanol sensing performance compared with pure matrix sensors.…”

“…In particular, Zhu and coworkers have reported that β -FeOOH/TiO 2 hierarchical heterostructures exhibited remarkably high sensitivity and reversibility [ 87 ]. Our group [ 95 ] demonstrated that the enhancement of the TiO 2 /Ag 0.35 V 2 O 5 gas sensor could be attributed to the extraordinary branched-nanofiber structures with large surface area and thin branch diameter (the semidiameter of the branches was equivalent to the depletion layer of the Ag 0.35 V 2 O 5 ), where more gas molecules could be absorbed and electrons in the Ag 0.35 V 2 O 5 nanobranches could be totally depleted by the oxygen molecules adsorbed on the surface ( Figure 10 b). Furthermore, Deng et al [ 110 ] have found that the enhanced performance of the ZnO-TiO 2 -based gas sensors could be ascribed to the hierarchical structures, as shown in Figure 12 , where the high specific surface area could result in a large number of gas molecules absorbed on the surface of ZnO-TiO 2 nanoheterostructures when compared with the pure TiO 2 nanofibers, additionally, well aligned structures of the nanoheterostructures would cause the unhindered gas diffusion to the whole surface of the sensor.…”

Design, Synthesis and Bioactivities of Novel Isoxazole-Containing Pyrazole Oxime Derivatives

“…In the past few decades, heterocycles play a significant role in the research of agricultural and medicinal chemistry. The isoxazole skeleton, a crucial type of nitrogen-containing heterocycle, has been used in pesticide and drug design because of their various biological activities, such as insecticidal [ 1 , 2 , 3 ], herbicidal [ 4 , 5 , 6 ], fungicidal [ 7 ], antiviral [ 8 , 9 , 10 ], and anticancer activities [ 11 ]. Recently, Yu et al obtained a series of 3,4,5-trisubstituted isoxazoles that were showing good insecticidal activities [ 12 ].…”

Synthesis Of 2′(2′,6′)-(Di)Halogenoisoxazolopodophyllic Acids-Based Amides Derived from a Naturally Occurring Lignan Podophyllotoxin and Their Acaricidal Activity

“…23 Melting points (mp) were determined on a XT-4 digital melting point apparatus. Optical rotation was measured on a Rudolph…”