Enantioselective hydrolyzation and photolyzation of dufulin in water

BACKGROUND: Dufulin 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. RESULTS: The 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. CONCLUSION: The photolysation and hydrolyzation of dufulin in water samples normally complied with the first-order kinetics and demonstrated acceptable linearity (R(2)>0.66). A preferential photolysation of the R-(−)-enantiomer was observed in water samples. Moreover, the S-(+)-enantiomer was hydrolyzed faster than its antipode.