PROCESS FOR THE PREPARATION OF PYRETHRINS AND ANALOGUES THEREOF AND INSECTICIDAL COMPOSITIONS CONTAINING THE SAME

摘要

The invention relates to a new process for the preparation of optically active or racemic pyrethrin compounds of general formula I (I ) (wherein R11 is a straight or branched chain lower alkyl group or 1-alkenyl group or hydrogen; R and R12 may be the same or different and stand for hydrogen, halogen or lower alkyl or one of the symbols R and R12 may also stand for lower alkoxycarbonyl; the ? valency bond represents .alpha.- and/or .beta.-configuration; the valency bond represents .beta. -configuration). The compounds are prepared by subjecting an optically active or racemic chrysanthemic ester derivative of formula II(wherein R11, R and R12, ? and - have the meanings given above) to oxidation by treatment with an oxidizing agent in an aprotic or inert organic solvent The pyrethrin compounds of formula I are valuable insecticides.