Shell Oil Comapny

Shell Internationale Research Maatschappij, B.v.

Johannes Van Berkel

Hendrik C Kelderman

Johannes L Syrier

Pieter A Verbrugge

Petrus A Kramer

Wilhelmus N Ruyters

A process for preparing a compound according to formula I containing substantially equimolar amounts of the 1R cis S- and the 1S cis R-isomers (the cis-2 enantiomer pair) and substantially free of the 1R cis R- and the 1S cis S-isomers (the cis-1 enantiomer pair), ##STR1## wherein R.sup.1 and R.sup.2 are each independently selected from chlorine, bromine and methyl, which process comprises contacting the cis-1 enantiomer pair, alone or in the presence of the cis-2 enantiomer pair, with an organic amine base containing from 5 to 7 carbon atoms and being a secondary amine containing two branched alkyl groups or being a tertiary amine, and then separating off a solid compound containing the cis-2 enantiomer pair and substantially free of the cis-1 enantiomer pair, characterized in that the reaction mixture is in the form a solid-liquid slurry.

Process for preparing cyclopropane carboxylic acid ester derivatives

2-(2,2-Dihalovinyl-3,3-dimethylcyclopropyl)vinyl alkanoates in which the alkanoate moiety contains from two to six carbon atoms are new chemical compounds useful as intermediates in the preparation of certain pyrethroid acids. The alkanoates are prepared by reacting 2-(2,2-dihalovinyl-3,3-dimethylcyclopropyl)ethanal with the appropriate alkanoic acid anhydride.

2-[2-(2,2-Dihalovinyl)-3,3-dimethylcyclopropyl ]vinyl alkanoates

New compounds of formula: ##STR1## wherein R.sup.1 is an alkyl group and R.sup.2 a 2-oxopropyl group or a 2,2-dihalovinyl group are prepared by elimination of an alcohol R.sup.1 OH from an acetal of formula: ##STR2## The compounds are intermediates in route to pyrethroid insecticides.

(Cyclopropyl)vinyl alkyl ether derivatives

New 2,2-dimethylcyclopropanecarbaldehyde dimethyl acetal derivatives of the formula ##STR1## wherein X is --CH.sub.2 OC(O)CH.sub.3, --CH.sub.2 OH, or --CHO are useful chemical intermediates for the preparation of pesticidally active cyclopropanecarboxylates.

2,2-Dimethylcyclopropanecarbaldehyde dimethyl acetal derivatives

2-(2,2-Dimethoxyethyl-3,3-dimethylcyclopropanecarbaldehyde and 2-[2-(2,2-dihalovinyl)-3,3-dimethylcyclopropyl]ethanal dimethyl acetals are new pyrethroid intermediates. They are prepared from 2-(2-hydroxymethyl-3,3-dimethylcyclopropyl)ethanal dimethyl acetal.

Cyclopropane derivatives

New 2-(2,2-dihalovinyl)-3,3-dimethylcyclopropane derivatives of the formula ##STR1## wherein each Hal is a halogen atom and R is dimethoxyethyl, 2-acetyl-3-oxobutyl, 2-methoxycarbonylpropyl or 2-acetyl-2-hydroxy-3-oxobutyl, are useful chemical intermediates for the preparation of pesticidally active cyclopropanecarboxylates.

2-(2,2-Dihalovinyl)-3,3-dimethylcyclopropanecarbaldehyde dimethyl acetal

2-(2,2-Dihalovinyl-3,3-dimethylcyclopropyl)ethanal is a new chemical compound and useful intermediate in the preparation of certain pyrethroid esters. It is prepared by hydrolysis of 2-[2-(2,2-dihalovinyl)-3,3-dimethylcyclopropyl]ethylidene diacetate, preferably in the presence of an acid.

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Amsterdam, Netherlands

Johannes Van Berkel