The synthetic pyrethroid isomers I. Preparation |
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Authors: | Béla Bertók Irene Czudor István Székely László Pap László Csíz Péter Forgó |
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Affiliation: | AGCHEM Chemical Research Department , CHINOIN Pharmaceutical and Chemical Works Co. Ltd. , P.O.B. 49, Budapest, H‐1780, Hungary |
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Abstract: | Abstract Enantiomers and racemic mixtures of selected benzilic esters using resolved and raceme permethrinic or chrysanthemic acids of high purity were synthesised via improved methods based on conventional steps. Nine basic structures of selected derivatives having hydrogen, bromo or phenoxy group at meta position were prepared including the well known insecticides of phenothrin, permethrin and cypermethrin. The optical purity of these compounds were determined via an NMR method applying chiral shift reagents. The configuration of the isomers of new a‐cyano‐benzyl esters were assigned via a rule realized by comparing the characteristic 1H NMR shifts of the dimethyl groups attached to the cyclopropane ring. |
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Keywords: | Cyclopropane carboxylic acid benzyl and α‐cyano benzyl esters cypermethrin permethrin phenothrin optical isomers |
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