Related Experiment Video
Updated: Aug 11, 2026

Functional Characterization of Carboxylesterases in Insecticide Resistant House Flies, Musca Domestica
Published on: August 23, 2018
Stereoselective degradation kinetics of theta-cypermethrin in rats
Qiuxia Wang1, Jing Qiu, Wentao Zhu
1Department of Applied Chemistry, China Agricultural University, Beijing 100094, China.
Abstract:
The enantioselective degradation and chiral conversion of theta-cypermethrin (TCYM) in rats have been studied via intravenous (i.v.) injection. The degradation kinetics and the enantiomer fraction (EF) were determined by means of normal-phase high-performance liquid chromatography (HPLC) with diode array detection (DAD) and a cellulosetris-(3,5-dimethylphenylcarbamate)-based chiral stationary phase (CDMPC-CSP). The degradation followed pseudo-first-order kinetics. The degradation of the (+)-TCYM was much faster than that of the (-)-TCYM in plasma, heart, liver, kidney, and fat after administration of racemic TCYM (rac-TCYM). The EFs were over 0.500 in these tissues and muscle. The results showed the conversion of (+)-enantiomer to (-)-enantiomer in plasma after injection of (-)- and (+)-TCYM separately. The results for the major differences in the degradation of the enantiomers may have some implication for the environmental and ecological risks assessment for chiral pesticides.
Related Concept Videos
Microbial Bioremediation of Pesticides
E2 Reaction: Stereochemistry and Regiochemistry
When a substrate with two different β hydrogens undergoes an E2 elimination, the presence of a strong base can yield two regioisomeric alkenes. The more-substituted alkene is the major product and...
E2 Reaction: Kinetics and Mechanism
SN2 Reaction: Stereochemistry
If the substrate is an achiral molecule at the α-carbon, the inversion of configuration is not observed.
E1 Reaction: Stereochemistry and Regiochemistry
Thermal Electrocyclic Reactions: Stereochemistry
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.

