Department of Applied Chemistry, China Agricultural University, Beijing 100193, China.
J Agric Food Chem. 2010 Dec 22;58(24):12878-84. doi: 10.1021/jf103537a. Epub 2010 Dec 1.
The enantioselective degradation behavior of fenoxaprop-ethyl (FE) and its chiral metabolite fenoxaprop (FA) in three soils under native conditions was investigated. Two pairs of enantiomers were analyzed by high-performance liquid chromatography (HPLC) with an amylose tri-(3,5-dimethylphenylcarbamate) (ADMPC) chiral column. The degradation of racemic FE in three soils showed the herbicidally inactive S-(-)-enantiomer degraded faster than the active R-(+)-enantiomer. FE was configurationally stable in soils because no interconversion to the respective antipodes was observed during incubation of the enantiopure S-(-)- or R-(+)-FE. The main metabolites of FE were confirmed as FA and 6-chloro-2,3-dihydrobenzoxazol-2-one (CDHB), and the formation of the chiral metabolite FA showed enantioselectivity in soils. The degradation of rac-FA was also enantioselective with the S-(-)-FA preferentially degraded: the half-life (t(1/2)) of the S-form in the three soils ranged from 2.03 to 5.17 days, and that of R-form ranged from 2.42 to 20.39 days. The inversion of the S-(-)-enantiomer into the R-(+)-enantiomer occurred in two of the three soils when the enantiopure S-(-)- and R-(+)-FA were incubated. The data from sterilized control experiments indicated that the enantioselectivity of FE and FA was attributed to microbially mediated processes.
在自然条件下,研究了 Fenoxaprop-ethyl(FE)及其手性代谢物 Fenoxaprop(FA)在三种土壤中的对映选择性降解行为。通过高效液相色谱(HPLC)用淀粉三-(3,5-二甲基苯基氨基甲酸酯)(ADMPC)手性柱分析了两对对映体。三种土壤中外消旋 FE 的降解表明,除草活性较弱的 S-(-)-对映体比活性较强的 R-(+)-对映体降解更快。FE 在土壤中结构稳定,因为在对映纯 S-(-)或 R-(+)-FE 的孵育过程中没有观察到相互转化为相应的对映体。FE 的主要代谢物被确认为 FA 和 6-氯-2,3-二氢苯并恶唑-2-酮(CDHB),并且在土壤中,手性代谢物 FA 的形成表现出对映选择性。rac-FA 的降解也具有对映选择性,S-(-)-FA 优先降解:三种土壤中 S 型的半衰期(t(1/2))范围为 2.03 至 5.17 天,而 R 型的半衰期范围为 2.42 至 20.39 天。当对映纯 S-(-)-和 R-(+)-FA 进行孵育时,两种土壤中 S-(-)-对映体转化为 R-(+)-对映体。灭菌对照实验的数据表明,FE 和 FA 的对映选择性归因于微生物介导的过程。