488113-10-6

Upstream product

• 66841-24-5 (R)-α-cyano-3-phenoxybenzyl (1R,3R)-trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate 
• 52315-07-8 cypermethrine 

Downstream Products

• 66841-24-5 (R)-α-cyano-3-phenoxybenzyl (1R,3R)-trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate 

Relevant academic research and scientific papers

Abiotic enantiomerization of permethrin and cypermethrin: Effects of organic solvents

All synthetic pyrethroids are chiral compounds, and isomerization has been frequently observed from exposure to certain solvents. However, so far, pyrethroid isomerization caused by solvents has not been characterized at the enantiomer level. In this study, we evaluated the occurrence of enantiomerization of two commonly used pyrethroids, permethrin and cypermethrin, in various organic solvents and solvent-water systems. The four stereoisomers of permethrin were stable under all test conditions. Rapid enantiomerization of cypermethrin was observed in isopropanol and methanol but not in n-hexane, acetone, or methylene chloride. After 4 days at room temperature, 18-39% conversions occurred for the different cypermethrin stereoisomers in isopropanol and methanol, and the enantiomerization invariably took place at the α-carbon position. The extent of enantiomerization was affected by temperature dependence and was also influenced by water as a cosolvent. In solvent-water mixtures, cypermethrin underwent gradual enantiomerization in acetone-water and rapid enantiomerization in isopropanol-water or methanol-water. The extent of enantiomerization varied among the solvents and as a function of the solvent-to-water ratio. Results from this study suggest that exposure to certain solvents and water may cause artifacts in chiral analysis and that for isomer-enriched pyrethroid products, such abiotic enantiomerization may render the products less effective because the conversion leads to the formation of inactive stereoisomers.

Epimerization of cypermethrin stereoisomers in alcohols

Isomerization induced by light, heat, and organic solvents has been shown to occur for some pyrethroid insecticides. Alcohols are popular solvents that are used in sample extraction, storage, and analysis. Thus, alcohol-induced epimerization may contribute to the incorrect interpretation of results from enantioselective chemical analysis and bioassay of pyrethroids like Cypermethrin. In this study, we investigated the relationship between the rate of epimerization of Cypermethrin stereoisomers: 1R-cis-αR and 1R-trans-αR and short-chain alkyl alcohol properties. In this study, complete epimerization of 1R-cis-αR produced an almost equal fraction of 1R-cis-αS, and that of 1R-trans-αR yielded 1R-trans-αS. For both stereoisomers, epimerization was most rapid in ethanol. The same stereoisomers underwent relatively rapid epimerization in methanol, n-propanol, 2-methyl1-propanol, and n-butanol but were stable in 2-butanol, suggesting that secondary alcohols have reduced reactivity, likely due to steric hindrance. We further evaluated epimerization of 1R-cis-αR and 1R-trans-αR stereoisomers of Cypermethrin as a function of water content in methanol. The presence of water in methanol generally increased the epimerization rate. For 1R-cis-αR, epimerization was most rapid with a water content of ≤2%, while for 1R-trans-αR, epimerization was most rapid with a water content of 10%. Results from this study clearly show that contact with commonly used primary alcohols may result in rapid abiotic epimerization, underscoring the importance of considering configurational stability in ensuring the analytical integrity and correct interpretation of bioassay data for stereoisomers of cypermethrin and similar pyrethroids. 2009 American Chemical Society.

Preparation of cyanoesters

A process for the preparation of certain cyano substituted esters and optical isomers thereof useful as insecticides by dehydration of the precursor carboxamido esters.