Imperial Chemical Industries Limited

David Holland

David J Milner

John Crosby

Roger K Huff

Dale A Laidler

Warren Hewertson

Hugh Wilma Reed

Chiral Schiff bases according to the general formula: ##STR1## and chiral transition metal complexes thereof, wherein at least the carbon atom of the monosaccharide to which the iminyl nitrogen atom is attached is asymmetric, and at least one of the carbon atoms adjacent the aforesaid carbon atom bears a hydroxyl group, R.sup.1 and R.sup.6 which may be the same or different, are hydrogen or lower alkyl, R.sup.2 is hydrogen, or lower alkyl or together with R.sup.10 forms a divalent hydrocarbon group, R.sup.3 is hydrogen, a sugar residue, or --CH.sub.2 OR.sup.10 in which R.sup.10 is hydrogen, lower alkyl or together with R.sup.2 forms a divalent hydrocarbon group, R.sup.4 is hydrogen or --CH.sub.2 OR.sup.10 in which R.sup.10 is hydrogen, or a lower alkyl, R.sup.5 is hydrogen, OR.sup.1 or a sugar residue, provided that both R.sup.4 and R.sup.5 are not hydrogen, R.sup.7 and R.sup.8 which may be the same or different, are hydrogen, or lower alkyl, or where p is 1, may with the cyclic ring to which CR.sup.7 R.sup.8 is attached form a fused system, R.sup.9 is hydrogen, alkyl, aralkyl, aryl or alkaryl, J is a chain of 3 or 4 atoms which with the group C A forms an aromatic system, which atoms may be carbon atoms or may be a mixture of carbon and one or more hetero atoms which may be the same or different, A is nitrogen, or ##STR2## or --NH--, L each of which may be the same or different, represents a substituent attached to a carbon atom in the chain J and is hydrogen, an alkyl group, aralkyl group, aryl, alkaryl or a substituent containing a hetero-atom; or two L's together with cyclic group to which they are attached form a fused system, m is 0 or 1, n is 0, 1 or 2, provided that n plus m is 0, 1, 2 or 3, p is 0, 1 or 2 and q is the number of carbon atoms in the chain J. The transistion metal is for example copper (II), chromium (II), manganese (II), iron (II), cobalt (II), nickel (II) or palladium (II). The aforesaid complexes may be used as catalysts in the cyclopropanation of olefins by diazoacetates to form insecticide or insecticide precursors.

Chiral sugar complexes

Process for the preparation of 3(2,2-dihalovinyl)-2,2-dimethyl cyclopropane carboxylic acids, especially permethrin acid ethyl ester, by reacting a diazoacetic acid ester with a 1,1-dihalo-4-methyl-1,3-pentadiene in the presence of a catalyst comprising a divalent rhodium salt of a carboxylic acid or borofluoric acid. The products have improved yields and better cis/trans isomer ratios than when the more common catalysts, e.g. copper-bronze, are used.

Preparation of cyclopropane carboxylic acid esters

3-Halogenoethyl- or propyl-2,2-dimethylcyclopropane carboxylic acid esters, which are intermediates in the preparation of synthetic pyrethroids, are prepared by the reaction of certain halogenopentenes or hexenes with a diazoacetic ester in the presence of a catalyst which is metallic copper or a copper (II) salt, a rhodium (II) salt of a carboxylic acid or a transition metal complex of certain chiral Schiff bases. By the use of the latter class of catalysts the yield of preferred cis IR isomer may be increased relative to the other possible isomers.

Process for the preparation of cyclopropane carboxylic acid esters

Polyhalogenated hydrocarbons of general formula RR.sup.1 CH--CHX--CH.sub.2 CYZQ wherein R is hydrogen or lower alkyl, R.sup.1 is lower alkyl, X is Cl, Br or I, Y is F, Cl or Br, Z is Y or Q and Q is a group W(CF.sub.2).sub.m --in which W is hydrogen, F or Cl and m is 1 or 2, provided that X is always Br or I when at least one of Y and Z is Br, and a process for preparing these polyhalogenated hydrocarbons by reacting an alkyl-substituted butene with a polyhalogenated alkane having from 2 to 4 carbon atoms, in the presence of a catalyst.

Polyhalogenated hydrocarbons, useful as insecticide intermediates, and

Process for the production of 2,5-dimethyl-1,5-hexadiene by heating isobutene with a 1,1,2-trihalo ethylene in the vapor phase in the presence of a free-radical generator. The free-radical generator is preferably a peroxide and the reaction temperature in the range 200.degree.-600.degree. C. The product may be readily isomerized to 2,5-dimethyl-2,4-hexadiene, which is useful as an insecticide intermediate.

2,5-Dimethyl-2,4-hexadiene production

Isobutene is oxidatively coupled with vinylidene chloride by heating in the presence of palladium acetate, to give 1,1-dichloro-4-methylpenta-1,3-diene. This compound is useful as an intermediate in the production of insecticides. Any 1,1-dichloro-4-methylpenta-1,4-diene also produced is thermally isomerized to the 1,3 product.

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Runcorn, United Kingdom

David Holland