Zeneca Limited

Syngenta Corporation

Syngenta Crop Protection, Inc.

Syngenta Participations Ag

Brian David Gott

Stephen Martin Brown

Thomas Gray

Seyed Mehdi Tavana

Martin Charles Bowden

David Anthony Jackson

James Peter Muxworthy

Iacob Eremia Gutu

Louie A Nady

Iacob Eremia Gutsu

The present invention relates to novel processes for the production of compounds of formula wherein Hal and Hal' are independently selected from Cl and F, and Ris selected from Cl, F and H.

Processes for the preparation of pyrazoles

The present invention relates to novel processes for the production of compounds of formula (I) wherein Hal and Hal' are independently selected from Cl and F, and Ris selected from Cl, F and H. 

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).

Process for preparing gamma-cyhalothrin

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.

Production process of gamma-cyhalothrin

A process for producing compounds of formula (VIIa) and (VIIb) wherein X is a leaving group; Y and Yare 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, Yand 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.

Process for the preparation of enantiomerically pure pyrethroid insecticides

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.

Process for the preparation of diphenyl ether compounds

Chemical process

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; and R.sup.3 is C.sub.1 -C.sub.4 alkyl, C.sub.2 -C.sub.4 alkenyl or C.sub.2 -C.sub.4 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 wherein the crystallisation solution contains not more than 25% loading of the compound of general formula I, loading being defined as: ##EQU1## and wherein the temperature to which the solution is cooled for crystallisation is not greater than about 30.degree. C.; wherein, after the addition of the crystallising solvent but before recrystallisation, the crystallisation solution is subjected to at least one wash with an aqueous solution having an acid pH followed by back extraction with fresh crystallising solvent. The process is particularly useful for purifying acifluorfen produced via a route starting with m-cresol.

Purification process

Process for the production of sulphonamides

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 ;

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Huddersfield, United Kingdom

Brian David Gott