Abstract: A process for the preparation of gamma-cyhalothrin comprising steps of a) chlorinating 1R cis-Z 3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethyl cyclopropanecarboxylic acid to give 1R cis-Z 3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethyl cyclopropanecarboxylic acid chloride and b) esterifying 1R cis-Z 3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethyl cyclopropanecarboxylic acid chloride with the (S)-cyanohydrin of 3-phenoxy benzaldehyde (III).

Abstract: A process for the preparation of gamma-cyahlothrin comprising a) chlorinating 1R cis-Z 3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethyl cyclopropanecarboxylic acid to give 1R cis-Z 3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethyl cyclopropanecarboxylic acid chloride; b) esterifying 1R cis-Z 3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethyl cyclopropanecarboxylic acid chloride with 3-phenoxy benzaldehyde in the presence of a source of cyanide to form a diastereoisomeric mixture of cyhalothrin isomers and c) epimerising the diastereoisomeric mixture under conditions in which the least soluble diastereoisomer crystallises from solution.

Abstract: A catalytic transfer hydrogenation process is provided. The catalyst employed in the process is a metal hydrocarbyl complex which is coordinated to defined bidentate ligands substituted with at least one group selected from an optionally substituted sulphonated hydrocarbyl group, a sulphonated perhalogenated hydrocarbyl group, or an optionally substituted sulphonated heterocyclyl group. Preferred metals include rhodium, ruthenium and iridium. Preferred bidentate ligands are diamines and aminoalcohols, particularly those comprising chiral centres. The hydrogen donor is advantageously a secondary alcohol or a mixture of triethylamine and formic acid. The process can be employed to transfer hydrogenate ketones and imines, which are preferably prochiral. Catalysts for use in such a process are also provided.

Abstract: A process for the preparation of 4-methyl-2,3,5,6-tetrafluorobenzyl alcohol comprising hydrogenating 4-methyl-2,3,5,6-tetrafluorobenzonitrile to 4-methyl-2,3,5,6-tetrafluorobenzylamine and converting 4-methyl-2,3,5,6-tetrafluorobenzylamine to 4-methyl-2,3,5,6-tetrafluorobenzyl alcohol. The process optionally also comprises the further step of reacting 4-Methyl-2,3,5,6-tetrafluobenzyl alcohol with cis-Z-3-(2-chloro-1,1,1-trifluoro-2-propenyl)-2,2-dimethylcyclopropanecarbonyl chloride to the form tefluthrin. 4-Methyl-2,3,5,6-tetrafluorobenzylamine and salts thereof are also claimed.

Abstract: A process for producing compounds of formula (VIIa) and (VIIb) wherein X is a leaving group; Y and Y1 are idependently Cl or Br; and Z is Cl, Br or a haloalkyl group which process comprises a) reacting a compound of formula (VII) wherein X, Y, Y1 and Z are as defined for compounds (VIIa) and (VIIb) with a substantially optically pure chiral amine in a solvent to form a diastereoisomeric salt; b) separating the diastereomeric salt of each enantiomer; c) converting the diastereomeric salt of each anantiomer separately to compounds of formulae (VIIa) and (VIIb) respectively by acid or base hydrolysis, the use of the compounds in making pyrethroid insecticides and novel intermediates.

Abstract: A process for producing fomesafen from acifluorfen comprises the steps of (a) converting acifluorfen to its acid chloride, (b) coupling the acid chloride so formed with methanesulphonamide to form crude fomesafen and (c) purifying the crude fomesafen, characterized in that each of the steps is carried out in a single common solvent, which is preferably a chloroalkane. Preferably the steps are telescoped together so that there is no isolation of the product for any step until fomesafen is obtained.

Abstract: A catalytic transfer hydrogenation process is provided. The catalyst employed in the process is a metal hydrocarbyl complex which is coordinated to defined bidentate ligands substituted with at least one group selected from an optionally substituted sulphonated hydrocarbyl group, a sulphonated perhalogenated hydrocarbyl group, or an optionally substituted sulphonated heterocyclyl group. Preferred metals include rhodium, ruthenium and iridium. Preferred bidentate ligands are diamines and aminoalcohols, particularly those comprising chiral centres. The hydrogen donor is advantageously a secondary alcohol or a mixture of triethylamine and formic acid. The process can be employed to transfer hydrogenate ketones and imines, which are preferably prochiral. Catalysts for use in such a process are also provided.

Abstract: A process for the preparation of 4-methyl-2,3,5,6-tetrafluorobenzyl alcohol comprising hydrogenating 4-methyl-2,3,5,6-tetrafluorobenzonitrile to 4-methyl-2,3,5,6-tetrafluorobenzylamine and converting 4-methyl-2,3,5,6-tetrafluorobenzylamine to 4-methyl-2,3,5,6-tetrafluorobenzyl alcohol. The process optionally also comprises the further step of reacting 4-Methyl-2,3,5,6-tetrafluobenzyl alcohol with cis-Z-3-(2-chloro-1,1,1-trifluoro-2-propenyl)-2,2-dimethylcyclopropanecarbonyl chloride to the form tefluthrin. 4-Methyl-2,3,5,6-tetrafluorobenzylamine and salts thereof are also claimed.

Abstract: A process for the preparation of 3,5-dichloropyridine comprising reacting a trichloropyridine, a tetrachloropyridine or pentachloropyridine with zinc metal, in the presence of an acidic compound and at a temperature in the range 50-120° C.

Abstract: A process for producing compounds of formula (VIIa) and (VIIb) wherein X is a leaving group; Y and Y1 are idependently Cl or Br; and Z is Cl, Br or a haloalkyl group which process comprises a) reacting a compound of formula (VII) wherein X, Y, Y1 and Z are as defined for compounds (VIIa) and (VIIb) with a substantially optically pure chiral amine in a solvent to form a diastereoisomeric salt; b) separating the diastereomeric salt of each enantiomer; c) converting the diastercomeric salt of each anantiomer separately to compounds of formulae (VIIa) and (VIIb) respectively by acid or base hydrolysis, the use of the compounds in making pyrethroid insecticides and novel intermediates.

Abstract: A process for the preparation of a compound of general formula I: 1

Abstract: A process for producing fomesafen from acifluorfen comprises the steps of (a) converting acifluorfen to its acid chloride, (b) coupling the acid chloride so formed with methanesulphonamide to form crude fomesafen and (c) purifying the crude fomesafen, characterized in that each of the steps is carried out in a single common solvent, which is preferably a chloroalkane.

Abstract: A process for the purification of a compound of general formula I: wherein: R1 is hydrogen or C1-C6 alkyl, C2-C6 alkenyl or C2-C6 alkynyl (any of which may optionally be substituted with one or more substituents selected from halogen and OH) or COOR4, COR6, CONR4R5 or CONHSO2R4; R4 and R5 are each independently hydrogen or C1-C4 alkyl optionally substituted with one or more halogen atoms; R6 is a halogen atom or a group R4; R2 is hydrogen or halo; R3 is C1-C4 alkyl, C2-C4 alkenyl or C2-C4 alkynyl, any of which may optionally be substituted with one or more halogen atoms, or halo; or, where appropriate, a salt thereof; from a mixture containing the compound of general formula I together with one or more isomers or di-nitrated analogues thereof; the process comprising dissolving the mixture in a suitable crystallisation solvent and recrystallising the product from the resulting crystallisation solution; characterised in that the crystallisation solution contains not more than 25% loadin

Abstract: A process for preparing a compound of formula (IV), wherein R1 is C1-4alkyl, CH2(C1-3haloalkyl), benzyl, CH2(C2-5akenyl or CH2(C2-5alkynyl), which comprises reducing a compound of formula (III). Compounds of formula (IV) are agrochemical intermediates.

Abstract: A process for preparing a compound of formula (IV) wherein R1 is C1-4 alkyl, C1-4 haloalkyl, benzyl, C3-6 alkenyl or C3-6 alkyny, (provided that the &agr;-carbon atom of R1 is neither unsaturated nor substituted with halogen), which comprises reacting a compound of formula (III) with a source of hydroxylamine in the presence of an acid. Compounds of formula (IV) are agrochemical intermediates.

Abstract: A process for preparing a compound of Formula (I); where Q completes an optionally substituted 5-or 6-member saturated carbocyclic ring and R is optionally substituted phenyl or optionally substituted C3-C6 cycloalkyl which comprises the rearrangement of a compound of Formula (II); where Q and R are as defined in relation to Formula (I) in a polar aprotic, dipolar aprotic or aromatic hydrocarbon solvent in the presence of a moderate base and an azole.

Abstract: 5-Chloro-2-(4,4-difluorobutylthio)thiazole is prepared from 2-mercaptotriazole by a multistep process involving S-alkylation, chlorination and dehydrochlorination and is converted by oxidation to the corresponding sulfone which is useful as an agricultural nematicide.

Abstract: The present invention provides the novel chlorofluorohydrocarbon 1,1-difluoro-1,4-dichlorobutane, and a process for its preparation comprising reacting 1,1,1,4-tetrachlorobutane or 1,1,4-trichlorobut-1-ene with hydrogen fluoride in the liquid or vapor phase. The product has useful solvent properties and is also useful in synthetic chemistry for the introduction of fluorocarbon functionality.

Abstract: A process for the purification of a compound of general formula I: ##STR1## wherein R.sup.1 is hydrogen or C.sub.1 -C.sub.6 alkyl, C.sub.2 -C.sub.6 alkenyl or C.sub.2 -C.sub.6 alkynyl, any of which may optionally be substituted with one or more substituents selected from halogen and hydroxy; or COOR.sup.4, COR.sup.6, CONR.sup.4 R.sup.5 or CONHSO.sub.2 R.sup.4 ;R.sup.4 and R.sup.5 independently represent hydrogen or C.sub.1 -C.sub.4 alkyl optionally substituted with one or more halogen atoms;R.sup.6 is a halogen atom or a group R.sup.4 ;R.sup.2 is hydrogen or halo; andR.sup.3 is C.sub.1 -C.sub.4 alkyl, C.sub.2 -C.sub.4 alkenyl or C.sub.2 -C.sub.

Abstract: A process for the preparation of a sulfonamide of formula:RSO.sub.2 NR.sup.1 R.sup.2wherein R represents C.sub.1 -C.sub.10 alkyl; andR.sup.1 and R.sup.2 independently represent hydrogen, C.sub.1 -C.sub.10 alkyl or C.sub.6 -C.sub.10 aryl; which comprises reacting the corresponding alkane- or arenesulfonyl halide of formula:RSO.sub.2 Halwherein Hal represents halogen; with the corresponding compound of formula:NHR.sup.1 R.sup.2in an aqueous solvent and extracting the sulfonamide from the resulting mixture into a polar organic solvent.