Zongde Wang

QSAR study of mosquito repellents from terpenoid with a six-member-ring

A new class of low-toxicity mosquito repellents is synthesized from alpha- and beta-pinene in terpenoid compounds and preliminary biological tests show promising mosquito repellency. Statistical modeling is built using Codessa in order to reveal the quantitative relationship between the structure and the biological activity and to provide the guidance for further synthetic work.

Quantitative structure-activity relationship of terpenoid aphid antifeedants.

A series of terpenoid compounds containing a six-member-ring were synthesized from alpha- and beta-pinenes. Antifeedant activity of these terpenoid compounds were tested on the aphid, Lipaphis erysimi (Kalt.), with promising results. Stepwise regression was applied to study the quantitative structure-activity relationship of these compounds. The statistically best model showed that the relative number of O atoms, molecular volume, HOMO-LUMO energy gap, and total charge on the positively charged fragments were the most statistically significant descriptors to predict the antifeedant activity. The possible mechanism of interaction between the antifeedant and aphid chemoreceptor was discussed.

Terpenoid mosquito repellents: a combined DFT and QSAR study.

Interactions between low-toxicity terpenoid mosquito repellents and lactic acid are studied at the HF and B3LYP level. The subsequent QSAR study shows that not only the structure of repellents but also the repellent-lactic acid complexes may play an important role. It suggests that further study on interactions between repellents and characteristic compounds from human host may be required in order to understand the repelling mechanism.

Synthesis and quantitative structure–activity relationship (QSAR) studies of novel rosin-based diamide insecticides

In a continuing effort to develop novel natural product-based insecticidal agents endowed with low mammalian toxicity, two series of rosin-based diamides have been synthesized, and their insecticidal activities against Plutella xylostella and Mythimna separata were evaluated. Most of the synthesized compounds exhibited moderate to significant insecticidal activity. Among them, thiadiazole-containing diamides 6a–n displayed better activity than others, especially compounds 6f and 6n which exhibited excellent insecticidal activity against P. xylostella, with LC50 values of 0.223 and 0.214 mg L−1, respectively, which approximate to, or are lower than that of, the control flubendiamide (0.222 mg L−1). The preliminary structure–activity relationship analysis indicated that rosin-based diamides with electron-withdrawing groups on the benzene ring showed better insecticidal activity than those with electron-donating groups. Via a best multilinear regression analysis, the generated quantitative structure–activity relationship (QSAR) model (R2 = 0.9566) revealed a strong correlation of insecticidal activity against P. xylostella with molecular structures of these compounds. These consequences can be expected to instruct the design and development of new rosin-based insecticides.

Synthesis of ordered porous SiO2 with pores on the border between the micropore and mesopore regions using rosin-based quaternary ammonium salt

A novel, sustainable, rosin-based quaternary ammonium salt, dehydroabietyltrimethyl ammonium bromine, has been applied for the synthesis of ordered hexagonal supermicroporous silica with nanosheet morphology. Unlike the conventional short chain surfactants, rosin-based surfactant possesses a rigid group of a three-ring phenanthrene skeleton. Such a hydrophobic group gives the surfactant a large total volume and small effective headgroup area, which are beneficial for the formation of 2D hexagonal phase. XRD, N2 adsorption–desorption, TEM, and SEM are used to characterize the samples. The results indicate that the molar ratios of mixture of silicate source, template agent and inorganic acid in the synthesis system have great effects on the regularity of the pore structure. The synthesized material possesses large surface area (1229 m2 g−1), high pore volume (0.59 cm3 g−1) and narrow pore size distribution (centered at about 2.03 nm), which is on the borderline between the micropore and mesopore regions. Such a material will be attractive for applications in separations and catalysis because of its potential shape and size selectivities.

Molecular interactions between terpenoid mosquito repellents and human-secreted attractants

Molecular interactions between terpenoid mosquito repellents and three typical human-secreted attractants, ammonia, 1-octen-3-ol, and formic acid were studied. Relative energies, bond distances, and bond angles of the molecular interactions were obtained at HF level to evaluate the interaction intensity and types. The effects of molecular interactions on repellency were investigated by the subsequent quantitative structure-activity relationship (QSAR) study. The results of this study suggest that attractant-repellent interaction should not be ignored and could be helpful for future research on the repelling mechanism of mosquito repellents.

Quantitative structure–activity relationship study of amide mosquito repellents

Abstract A quantitative structure–activity relationship (QSAR) study on 43 amide repellents was carried out by the heuristic method in order to reveal the correlations between molecular parameters of these amides and their repellency against Aedes aegypti. Sketches and optimizations of molecular structures were achieved by the Gaussian software package. Generation and screening of molecular parameters were accomplished using CODESSA 2.7.10 software. The leave-one-out method was applied for the model validation. The results showed that a four-descriptor QSAR model with r2 of 0.897 was obtained. The average r2 values of the training set and test set of the QSAR model were 0.901 and 0.863, respectively, which suggested that the stability and predictability of the model were confirmed. Analysis of the implications of the descriptors that constitute the QSAR model indicated that all the descriptors were related to the charge distribution over the molecule and affect the dipole moment of the repellents.

Hydronopylformamides: Modification of the Naturally Occurring Compound (-)-β-Pinene to Produce Insect Repellent Candidates against Blattella germanica

The development of a novel repellent plays an important role in the integrated control of Blattella germanica. A series of novel hydronopylformamides derivatives were synthesized from a naturally occurring compound (-)-β-pinene. The structures of these hydronopylformamides derivatives were characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (1H-NMR and 13C-NMR), and electron impact mass spectrometry (EI-MS). Repellency of these hydronopylformamides derivatives against Blattella germanica was evaluated by the using petri dish arena method. The results showed that four derivatives (compounds 8a, 8b, 8c and 8e) exhibited repellency against Blattella germanica at a concentration of 20 mg/mL. Compound 8a was the most active compound among these derivatives, where the repelling ratios of compound 8a against Blattella germanica were 66.10%, 50.46%, 48.26%, at concentrations of 20 mg/mL, 10 mg/mL, and 5 mg/mL, respectively. In addition, compound 8a showed better repellency than the traditional insect repellent N, N-diethyl-3-methylbenzamide (DEET), which indicated that compound 8a had a good application prospect in the prevention of Blattella germanica. This research hopes to promote the value-added utilization of (-)-β-pinene and the development of novel German cockroach repellents.

2-[(1S,3S)-3-Acetyl-2,2-dimethyl­cyclo­butyl]-N-(m-tol­yl)acetamide

The title compound, C17H23NO2, contains two chiral centres and was synthesized from 2-(3-acetyl-2,2-dimethylcyclobutyl)acetic acid and m-toluidine. The cyclobutane ring is not flat but flexed as though folded from the dimethyl-substituted C atom to the unsubstituted C atom, with a dihedral angle of 25.9°. The crystal structure is stabilized by N—H⋯O and C—H⋯O hydrogen-bonding interactions.