Abstract: This invention relates to the preparation of cyclopropane carboxylic acid ester derivatives, which are useful as pesticides.There is provided a process for preparing a 1:1 mixture of 1R cis S- and 1S cis R- isomers substantially free of 1S cis S- and 1R cis R- isomers of a compound of formula: ##STR1## wherein R.sup.1 and R.sup.2 are each independently selected from chlorine, bromine and methyl, which process comprises dissolving a mixture of 1S cis S- and 1R cis R- isomers of the compound of formula I, alone or in the presence of 1R cis S- and 1S cis R-isomers, in organic amine base containing from 5 to 7 carbon atoms and being a secondary amine containing two branched alkyl groups or a tertiary amine, and crystallizing out from the resulting solution of cis - isomers of formula I in the organic amine base a 1:1 mixture of the 1R cis S- and 1S cis R- isomers substantially free of 1S cis S- and 1R cis R- isomers.

Abstract: A method for preparing a pyrethroid insecticide of general formula: ##STR1## wherein the two hydrogen atoms on the cyclopropane ring are in the cis- configuration, in which an acid of formula: ##STR2## is neutralized with a water-soluble base and then reacted in the presence of a phase-transfer catalyst with a solution in a substantially water-immiscible organic solvent of an alpha-cyanobenzyl aryl sulphonate of formula: ##STR3## the substituents in the formulae having the following meanings; A represents an optionally substituted aryl group; R.sub.1 and R.sub.2 represent hydrogen or halogen; and R.sub.3 and R.sub.4 represent chlorine, bromine, or methyl.

Abstract: Mixtures of the geometric isomeric forms of 3-azabicyclo-(3.1.0)hexane-2-carbonitrile are resolved by selective extraction of a mixture of their benzenesulfonic acid salts or their toluenesulfonic acid salts.

Abstract: Phenoxybenzyl esters are prepared by neutralizing an aqueous solution of a carboxylic acid and contacting the neutralized solution with a solution of phenoxybenzyl halide in a water-immiscible base in the presence of a phase transfer catalyst.

Abstract: Certain carboxylic acid esters also containing a cyano group are prepared by reacting an acid halide, an aldehyde and a water-soluble cyanide in the presence of a water immiscible aprotic solvent and preferably a phase-transfer catalyst.

Abstract: Meta-aryloxybenzaldehydes are prepared by treating a mixture of meta-aryloxybenzyl- and benzal halides with hexamethylenetetramine (or equivalent amounts of ammonia and formaldehyde) and hydrolyzing the resulting product under acid conditions.

Abstract: Phenoxybenzyl esters are prepared by neutralizing an aqueous solution of a carboxylic acid and contacting the neutralized solution with a solution of phenoxybenzyl halide in a water-immiscible base in the presence of a phase transfer catalyst.

Abstract: 3-PHENOXYBENZYL BROMIDE IS PREPARED BY TREATING 3-PHENOXYTOLUENE WITH BROMINE IN THE PRESENCE OF ULTRA-VIOLET RADIATION, AT A TEMPERATURE IN THE RANGE OF FROM 180.degree. C to 250.degree. C.

Abstract: Alkyl esters of 3-cyano-3-(3-phenoxyphenyl)-2-ketopropionic acid, useful as precursors for the preparation of insecticidal esters of 3-phenoxy-.alpha.-cyanobenzyl alcohol.