Turpentine Derived Secondary Amines for Sustainable Crop Protection: Synthesis, Activity Evaluation and QSAR Study

Abstract

In this study, we will report on the synthesis and application of efficient botanical agrochemicals from turpentine for sustainable crop protection. Two series of turpentine derived secondary amines were synthesized and identified by FT-IR, 1H NMR, 13C NMR, and HRMS. The herbicidal activities against Echinochloa crus-galli were evaluated. The potential toxicity of the synthesized compounds was tested by MTT cytotoxicity analysis. The effect of structure of the synthesized secondary amines and corresponding Schiff base compounds on their activities was investigated by quantitative structure–activity relationship (QSAR) study. All target products were found to be low toxicity, with similar or higher herbicidal activities than commercial herbicides diuron and Glyphosate. Results of QSAR study showed that a best four-descriptor QSAR model with R 2 of 0.880 and R loo 2 of 0.818 was obtained. The four descriptors most relevant to the herbicidal activities are the min valency of a N atom, the max total interaction for a C−H bond, the relative number of aromatic bonds, and the min partial charge (Q min ).

Synthesis, Herbicidal Activity and Toxicity Evaluation of Secondary Ammonium Salts from Turpentine Oil for Sustainable Weed Control

“…p ‐Menth‐3‐enylamine, cis‐ 1,8‐ p ‐menthane‐diamine, and p‐ menthene‐7‐amine secondary amines were synthesized from α / β ‐pinene in our laboratory following literature procedures [16,17] . Other chemicals and reagents were commercially available and used without further purification.…”

“…The structureactivity-relationship analysis of test salts against barnyard grass further confirmed that the introduction of electron-withdrawing substituents on the benzene ring favors herbicidal activity. The relationship between the structure of the turpentine-derived secondary amines and their herbicidal activities against barnyard grass has been discussed by QSAR (Quantitative structure -activity relationship) analysis in our previous research and four values with the greatest influence on herbicidal activity were obtained, [17] which could also be applied to the new secondary ammonium chloride. Turpentine derivatives generally show low toxicity and high biocompatibility, and some of them have been widely used in the preparation of fragrances and spices.…”

“…According to our previous study, p‐ menthane and p‐ menthene secondary amine compounds, including sec ‐ p ‐menth‐3‐enylamines, sec ‐ is ‐1,8‐ p ‐menthane‐diamines, and sec ‐ p ‐menthene‐7‐amines all possess low toxicity, potential herbicidal efficacy, and a broad spectrum against some noxious weeds [16–20] . However, the poor water‐solubility of these amine derivatives caused concerns in herbicidal applications, such as the overdose of herbicidal active substances and the excessive use of organic solvents and additives, which will have adverse effects on large‐scale application and sustainable development.…”

Design, Synthesis and Antifungal/Nematicidal Activity of Novel 1,2,4-Oxadiazole Derivatives Containing Amide Fragments

“…The cells were grown in Dulbecco's Modified Eagle's Medium (supplemented with 10% (v/v) FBS, 100 U/mL penicillin, and 100 µg/mL streptomycin) at 37 • C in a CO 2 incubator (5% CO 2 and 95% air, 95% humidity). The effect of some compounds on cell viability was determined with the MTT assay according to the previously published literature [45,46]. A total of 5000 cells were inoculated in a 96-well plate and three wells of each concentration of test compound were used.…”

Design, synthesis, and herbicidal activity of sec-p-menthane-7-amine derivatives as botanical herbicides

“…It has been proven that secondary amines such as sec-p-menth-3-enylamines and cis-1,8-p-menthane-di-sec-amines exhibit higher herbicidal activities than that of Schiff bases, and they show low toxicity to common crops and mammal cells. 26,27 Perillaldehyde is a natural monoterpene of the p-menthane group originating from plant Perilla frutescens. It was reported that perillaldehyde displayed various bioactivities such as antidepression and antibacterial activity, 28,29 but the herbicidal activity is rarely reported.…”