Yanqing Gao

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.

A value-added use of volatile turpentine: antifungal activity and QSAR study of β-pinene derivatives against three agricultural fungi

In consideration of turpentine and its analogues possessing some agricultural biological activity, persistent efforts to take advantage of renewable, abundant natural resources have been made. Three series of derivatives from β-pinene were synthesized and their fungicidal activities against Rhizoctonia solani, Fusarium graminearum, and Botrytis cinerea were investigated. Most of the synthesized compounds exhibited moderate to significant fungicidal activity. Among them, the acylthiourea derivatives from β-pinene showed more promising results than the other compounds. It was worth noting that compounds 7b and 7d displayed excellent fungicidal activity against Rhizoctonia solani, with IC50 values of 2.439 and 1.857 μg mL−1, which was close to or even better than the control triadimenol (1.945 μg mL−1, a commercial fungicide). The structure–activity relationship (SAR) analysis indicated that the compounds with more net positive charge possessed better fungicidal activity. The quantitative structure–activity relationship (QSAR) model (R2 = 0.9879, F = 348.41, S2 = 0.0047) was obtained through the best multi-linear regression. The built model revealed a strong correlation of fungicidal activity against Rhizoctonia solani with the molecular features of the title compounds. Additionally, the SAR and QSAR studies showed that the introduction of an electron-withdrawing group, which can increase the positive charge, was favorable towards the fungicidal activity. These encouraging results may provide an alternative, promising use of β-pinene through the design and exploration of eco-friendly fungicides with low toxicity and high efficiency.

Syntheses and antibacterial activity of Schiff bases from 16-isopropyl-5, 9-dimethyltetracyclo [10.2.2.01, 10.04, 9] hexadec-15-ene-5, 14-dicarboxylic acid

16-Isopropyl-5, 9-dimethyltetracyclo [10.2.2.01, 10.04, 9] hexadec-15-ene-5, 14-dicarboxylic acid (1b) was prepared from rosin through a Diels–Alder addition reaction. Then, a group of Schiff bases derived from 1b was synthesised. Their structures were characterised by IR,1H-NMR, MS and elemental analysis. The antibacterial activities of these newly synthesised Schiff bases were also investigated. The results show that these compounds possess antibacterial activities against Staphylococcus aureus and Escherichia coli. Among them, compounds 5a, 5b and 5c, exhibit remarkable antibacterial activity against E. coli.

High Add Valued Application of Turpentine in Crop Production through Structural Modification and QSAR Analysis

Turpentine is a volatile component of resin, which is an abundant forest resource in Southern China. As one of the most important components, the integrated application of β-pinene has been studied. The broad-spectrum evaluation of β-pinene and its analogues has, therefore, been necessary. In an attempt to expand the scope of agro-activity trials, the preparation and the evaluation of the herbicidal activity of a series of β-pinene analogues against three agricultural herbs were carried out. In accordance with the overall herbicidal activity, it is noteworthy that compounds 6k, 6l, and 6m demonstrated extreme activity with IC50 values of 0.065, 0.065, and 0.052 mol active ingredients/hectare against E. crus-galli. The preliminary structure–activity relationship (SAR) was analyzed and the compounds with the appropriate volatility and substituent type that had beneficial herbicidal activity were analyzed. Simultaneously, the quantitative structure–activity relationship (QSAR) model was built and the most important structural features were indicated, which was, to a certain extent, in line with the SAR study. The study aimed to study the application of the forest resource turpentine in agriculture as a potential and alternative approach for comprehensive utilization.