PROCESS FOR THE PREPARATION OF CYPERMETHRINE ISOMERS

• Main Authors: HEGEDUS, AGNES, GAJARY, ANTAL, ISTVAN, SZEKELY, SOMFAI, EVA, TARY, MARIA, BOTAR, SANDOR, HAJIMICHAEL, JANIS, ZOLTAN, SANDOR, LAK, ISTVAN, GYORGY HIDASI, NAGY, LAJOS, BELA, BERTOK, RAPI, ANDRAS
• Format: Patent
• Language: English; French
• Published: 18.07.1990
• Edition: 5
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; AGRICULTURE; ANIMAL HUSBANDRY; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES, AS HERBICIDES; CHEMISTRY; FISHING; FORESTRY; HUMAN NECESSITIES; HUNTING; METALLURGY; ORGANIC CHEMISTRY; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS; PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTSTHEREOF; TRAPPING

The invention relates to a process for the preparation of such isomer mixtur es of cypermethrine of formula (I), wherein car- bon atoms indicated by 1,3 and .alpha. stand for a chiral carbon atom and th e wavy line indicates cis or trans configuration related to the cyclopropane ring - which contains out of the theoretically possible 8- isomers of cypermethrine at least 95 % of 1 RtransS and 1StransR (Ib) isomer pair or only a mixture of 1RcisS and 1ScisR (Ia) and th e isomer pair (Ib) of the ratio (Ia):(Ib) = 55:45 - 25:75 by asymmetric transformation of second order performed in the presence of an amine base and solvent from a starting cy- permethrine isomer mixture which contains next to the isomer pair (Ib) cis a nd other trans isomers or the isomer pair Ia + Ib at an undesired ratio. 2020356 9008132 PCTABS00001 The invention relates to a process for the preparation of such isomer mixtures of cypermethrine of formula (I), wherein carbon atoms indicated by 1,3 and .alpha. stand for a chiral carbon atom and the wavy line indicates cis or trans configuration related to the cyclopropane ring - which contains out of the theoretically possible 8-isomers of cypermethrine at least 95 % of 1RtransS and 1StransR (Ib) isomer pair or only a mixture of 1RcisS and 1ScisR (Ia) and the isomer pair (Ib) of the ratio (Ia):(Ib) = 55:45 - 25:75 by asymmetric transformation of second order performed in the presence of an amine base and solvent from a starting cypermethrine isomer mixture which contains next to the isomer pair (Ib) cis and other trans isomers or the isomer pair Ia + Ib at an undesired ratio.