Enantioselective hydrolyzation and photolyzation of dufulin in water

Abstract

BackgroundDufulin is a novel, highly effective antiviral agent that activatives systemic acquired resistance of plants. This compound is widely used in China to prevent and control viral diseases in tobacco, vegetable and rice. Dufulin can treat plants infected by the tobacco mosaic virus and the cucumber mosaic virus. However, the achiral analysis and residue determination of dufulin remain underdeveloped because of its high enantioselectivity rates and high control costs. The enantioselectivity of an antiviral compound is an important factor that should be considered when studying the effect of chiral pesticides on the environment. The enantioselective degradation of dufulin in water remains an important objective in pesticide science.ResultsThe configuration of dufulin enantiomers was determined in this study based on its circular dichroism spectra. The S-(+)-dufulin and R-(−)-dufulin enantiomers were separated and identified using an amylose tris-(3,5-dimethylphenylcarbamate) chiral column by normal phase high-performance liquid chromatography. The degradation of the rac-dufulin racemate and its separate enantiomers complied with first-order reaction kinetics and demonstrated acceptable linearity. The enantioselective photolysis of rac-dufulin allowed for the faster degradation of R-(−)-dufulin, as compared with S-(+)-dufulin. However, S-(+)-dufulin was hydrolyzed faster than its antipode.ConclusionThe photolysation and hydrolyzation of dufulin in water samples normally complied with the first-order kinetics and demonstrated acceptable linearity (R2>0.66). A preferential photolysation of the R-(−)-enantiomer was observed in water samples. Moreover, the S-(+)-enantiomer was hydrolyzed faster than its antipode.

Enantioselective degradation of dufulin pesticide in water: Uptake, thermodynamics, and kinetics studies

“…Much work has not been carried out on enantioselective degradation of dufulin pesticide. However, the efforts were made to compare the results with those available in the literature . The values of the rate constant reported were in the range of 0.0083 to 0.0339 d −1 while the values of the rate constant described in this manuscript were in the range of 0.05 to 0.051 d −1 .…”

“…It is used to control plant viruses like tobacco and cucumber mosaic virus, potato virus Y, tomato mosaic virus, and the southern rice black streaked dwarf virus. There are not many studies on the toxicity profile of dufulin . However, Rulcova et al reported some toxicity when dufulin was injected into rats.…”

Enantioselective Dissipation of Acephate and Its Metabolite, Methamidophos, during Tea Cultivation, Manufacturing, and Infusion

“…This suggested that significant enantioselectivity of acephate and methamidophos probably occurred during tea infusion. However, the reason for this 49 which needs further investigation. Transfer rates of acephate and methamidophos enantiomers were higher than 80.5% and 89.1%, respectively.…”

Enantioseparation and determination of dufulin enantiomers in cucumber and soil by chiral liquid chromatography–tandem mass spectrometry

“…At present, studies of dufulin are mainly focused on antiviral activity (Chen et al, ; Hu et al, ; Wang et al, ), residual analysis (Chen et al, ; Chen, Li, et al, ; Li et al, ; Lu, Yang, Hu, Ding, & Shi, ; Miao, Wang, Lu, Geng, & Yang, ; Zhang, Meng, et al, ; Zhu et al, ) or degradation mechanisms in an achiral way (Wang et al, ). Moreover, only three papers have reported on the enantioselective separation of dufulin (Zhang et al, ; Zhang, Hu, Zhu, Yang, & Song, ; Zheng et al, ). For example, Zhang, Hu, et al () established a simple chiral separation of dufulin by normal‐phase high‐performance liquid chromatography in soil, and Zheng et al () used ultra‐high‐performance liquid chromatography with high‐resolution mass spectrometry to determine two dufulin enantiomers in watermelon.…”