GB1601552A - Process for the preparation of 2-(2',2',2'-trihalogenoethyl)-4-halogenocyclobutan-1-ones - Google Patents

Description

(54) PROCESS FOR THE PREPARATION OF 2-(2' ,2',2'-TRIHALOGENOETHYL)-4- HALOGENOCYCLOBUTAN-1 -ONES (71) We, CIBA-GEIGY AG, a Swiss Body Corporate, of Basle, Switzerland, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to a process for the preparation of 2 - (2',2',2' trihalogenoethyl) - 4 - halogenocyclobutan - 1 - ones of the formula I

in which one of the radicals R1 and R2 is methyl and the other is hydrogen or methyl, or R1 and R2 together are an alkylene group having 2 to 4 carbon atoms, and X and Y are each chlorine or bromine, but if X is bromine Y must always also be bromine.

The present invention also relates to the novel 2 - (2',2',2' trihalogenoethyl) - 4 - halogenocyclobutan - 1 - ones of the formula I which can be prepared by the process according to the invention.

It is known that -halogenocycloalkanones are converted on heating in the presence of bases. such as alkali metal hydroxides and alkali metal alcoholates, to cycloalkanecarboxylic acids having the same number of carbon atoms, or esters thereof, with contraction of the ring (Favorski reaction). This reaction is the basis for an industrially important process for the preparation of cyclopropanecarboxylic acid derivatives and their esters having an insecticidal action, i.e. the pyrethroids, from a-halogenocyclobutanones. However, it was not possible to use this process, which is technically simple to carry out, for the preparation of pyrethroids which are derived from 2 - (2',2' - dihalogenovinyl) - cyclopropanecarboxylic acid, since corresponding a--halogenocyclobutanones suitable for the preparation of such cyclopropanecarboxylic acid derivatives were not available.

It has already been proposed to prepare a-halogenocyclobutanones by reacting a halogenoketene with an olefine. Processes of this type are described, for example, in German Offenlegungsschrift 2,539,048 and British Patent Specification 1,194,604 and also in J. Amer. Chem. Soc. 87, 5257-5259 (1965) and in Tetrahedron Letters No. 1, 135-139 (1966). This synthesis principle has not been used hitherto for the preparation of a-halogenobutanones, which are suitable as intermediates for the preparation of 2 - (2',2' - dihalogenovinyl) cyclopropanecarboxylic acids and their esters having an insecticidal action. This is in particular due to the fact that the synthesis possibilities which are conceivable on the basis of the above-mentioned method, i.e.

a) reaction of a halogenated olefine with a halogenoketene in accordance with the equation:

or b) reaction of an unhalogenated olefine with a halogenoketene in accordance with the equation:

the symbols R1, R2, X and Y in the above equations being as defined under formula I, do not lead to the 2 - (2',2',2' - trihalogenoethyl) - 4 - halogenocyclobutan - I ones of the formula I, which are required as intermediates, since the reaction according to a) does not take place because of the deactivation of the olefine which is associated with the substitution by halogen and the reaction according to b) results in a 2 - (2',2',2' - trihalogenoethyl) - 2 - halogenocyclobutan - 1 - one which cannot be converted into a 2- (2',2' - dihalogenovinyl)cyclopropanecarboxylic acid, or an ester thereof, using an alkali metal hydroxide or alkali metal alcoholate.

The object of the present invention is, therefore, to provide a process for the preparation of 2 - (2',2',2' - trihalogenoethyl) - 4 - halogenocyclobutan - 1 - ones of the formula I which uses readily accessible starting materials and is simple to carry out.

The 2 - (2',2',2' - trihalogenoethyl) - 4 - halogenocyclobutan - 1- - ones of the formula I, which have not been known hitherto, on heating with strong bases, such as alkali metal hydroxides or alkali metal alcoholates, give the corresponding 2 - (2',2' - dihalogenovinyl)- cyclopropanecarboxylic acid derivatives, with contraction of the ring and, at the same time, the elimination of 2 mols of hydrogen halide.

It has now been found that 2 - (2',2',2' - trihalogenoethyl) - 4halogenocyclobutan - 1 - ones of the formula I can be prepared in a simple manner by reacting a 2,4,4,4 - tetrahalogenobutyric acid chloride of the formula 11

in which X and Y are as defined under formula I, in the presence of an organic base with an olefine of the formula III

in which R, and R2 are as defined under formula I, to give a 2 - (2',2',2' trihalogenoethyl) - 2 - halogenocyclobutan - 1 - one of the formula IV

in which R1, R2, X and Y are as defined under formula I, and then rearranging the latter, in the presence of a catalyst, into a 2 - (2',2',2' - trihalogenoethyl) - 4 halogenocyclobutan - 1 - one of the formula I.

The 2.4,4,4 - tetrahalogenobutyric acid chlorides of the formula II are novel compounds, which are the subject of our Application No. 8031151 (1,601,553) divided out of the present Application. They can be prepared in a manner known per se by adding a carbon tetrahalide of the formula V

in which X and Y are as defined under formula I, onto a compound of the formula VI CH2=CH-Z (VI) in which Z is chlorocarbonyl, carboxyl, alkoxycarbonyl having 1 to 4 carbon atoms in the alkyl group, or cyano, and converting resulting compounds of the formula VII

in which X and Y are as defined under formula I and Z is carboxyl, alkoxycarbonyl or cyano, into compounds of the formula VII in which Z is chlorocarbonyl.

A further possibility for the preparation of 2,4,4,4 - tetrahalogenobutyric acid chlorides of the formula II comprises adding a compound of the formula Via

in which Z is as defined under formula VI, onto 1,1 - dichloroethylene and converting resulting compounds of the formula VIIa

in which Z is carboxyl, alkoxycarbonyl or cyano, into compounds of the formula Villa in which Z is chlorocarbonyl.

When adding a carbon tetrahalide of the formula V onto an acrylic acid derivative of the formula VI and also when adding a dichloroacetic acid derivative of the formula VIa onto 1, I-dichloroethylene, the carbon tetrahalide of the formula V and. respectively, the dichloroacetic acid derivative of the formula Via can be emploved in stoichiometric amount. Preferably, however, an excess of the carbon tetrahalide of the formula V or the dichloroacetic acid derivative of the formula VIa, for example an approximately 0.5-fold to 2-fold molar excess, is used and the carbon tetrahalide of the formula V can also serve as a solvent.

The adding of a carbon tetrahalide of the formula V onto a compound of the formula VI, and also the adding of a compound of the formula VIa onto 1,1 dichioroethylene, is carried out in the presence of catalysts. Suitable catalysts are metals of principal group VIII and sub-groups VIa, Villa and Ib of the periodic system, for example iron, cobalt, nickel, ruthenium, rhodium, palladium.

chromium, molybdenum, manganese and copper. These metals can be employed in the elemental form or in the form of compounds. Suitable compounds of these metals are, for example, oxides, halides, sulphates, sulphites, sulphides, nitrates.

acetates, citrates, carbonates, cyanides and thiocyanates, and also complexes with ligands, such as phosphines, phosphites, benzoin, benzoyl- and acetyl-acetonates.

nitriles, isonitriles and carbon monoxide.

Examples of compounds of the abovementioned metals which are suitable as catalysts are: copper-II oxide, iron-llI oxide, the bromides, and in particular the chlorides, of Cu-I, Cu-II, Fe-Il and Fe-III, and also the chlorides of ruthenium.

rhodium, palladium, cobalt and nickel: Cu-II sulphate, Fe-II sulphate and Fe-Ill sulphate, Cu-II nitrate and iron-III nitrate; manganese-Ill acetate and copper-ll acetate: copper-II stearate: iron-lII citrate: Cu-I cyanide, ruthenium-II dichloro tris - triphenylphosphine and rhodium tris-(triphenylphosphine) chloride; chromium acetylacetonate and nickel acetylacetonate, copper-II acetylacetonate iron-lII acetylacetonate, cobalt-II acetylacetonate and cobalt-llI acetylacetonate.

manganese-II acetylacetone and copper-II benzoylacetonate, iron carbonylcyclopentadienyl complex; molybdenum carbonyl-cyclopentadienyl complex.

chromium tricarbonyl-aryl complexes, ruthenium-II acetocomplex, chromium hexacarbonyl and molybdenum hexacarbonyl, nickel tetracarbonyl, iron pentacarbonyl, cobalt carbonyl and manganese carbonyl.

Mixtures of the said metals with metal compounds and/or other additives can also be used, such as copper powder in combination with one of the abovementioned copper compounds; mixtures of copper powder with lithium halides, such as lithium chloride, or with isocyanides, such as tert.-butyl isocyanide: mixtures of iron powder with iron-Ill chloride, if desired with the addition of carbon monoxide: mixtures of iron-III chloride and benzoin; mixtures of iron-lI chloride or iron-llI chloride and trialkyl phosphites; and mixtures of iron pentacarbonyl and iodine.

Preferred catalysts are iron-lI salts and complexes and iron-III salts and complexes and also iron powder, but in particular copper powder, copper-I salts and complexes and copper-lI salts and complexes, such as Cu-I chloride, Cu-I I chloride, Cu-I bromide, Cu-ll bromide, Cu-ll acetylacetonate, Cu-I I benzoylacetonate, Cu-Il sulphate. Cu-ll nitrate and Cu-I cyanide.

Very particularly preferred catalysts are copper powder, copper-I chloride and bromide and copper-II chloride and bromide, as well as mixtures thereof The said catalysts are generally used in amounts of about 0.01 to 10 mol preferably 0.1 to 5 mol ,, based on the compound of the formula III or the 1,1- dichloroethylene.

The addition reactions are carried out in an organic solvent. Suitable organic solvents are those in which the catalysts are adequately soluble or which can form complexes with the catalysts, but which are inert towards the starting compounds.

Examples of such solvents are alkylnitriles, especially those having 2-5 C atoms, such as acetonitrile, propionitrile and butyronitrile; 3-alkoxypropionitriles having 1 or 2 C atoms in the alkoxy moiety, such as 3-methoxypropionitrile and 3 ethoxypropionitrile; aromatic nitriles. in particular benzonitrile: aliphatic ketones having, preferably, a total of 3-8 C atoms, such as acetone, diethyl ketone, methyl isopropyl ketone, diisopropyl ketone and methyl tert.-butyl ketone; alkyl esters and alkoxyalkyl esters of aliphatic monocarboxylic acids having a total of 2-6 C atoms, such as methyl formate and ethyl formate, methyl acetate, ethyl acetate, n-butyl acetate and isobutyl acetate, and also 1 - acetoxy - 2 - methoxyethane; cyclic ethers, such as tetrahydrofurane, tetrahydropyrane and dioxane: dialkyl ethers having 1-4 C atoms in each alkyl moiety. such as diethyl ether, di-n-propyl ether and di-isopropyl ether; N,N-dialkylamides of aliphatic monocarboxylic acids having 1-3 C atoms in the acid moiety, such as N,N-dimethylformamide N,Ndimethylacetamide, N,N-diethylacetamide and N,N-dimethylmethoxy-acetamide: ethylene glycol dialkyl ethers and diethylene glycol dialkyl ethers having 1-4 C atoms in each alkyl moiety, such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether and ethylene glycol di-n-butyl ether, and diethylene glycol diethyl ether and diethylene glycol di-n-butyl ether; and hexamethylphosphoric acid triamide (Hesametapol).

Preferred solvents are alkylnitriles having 2-5 C atoms and 3alkoxypropionitriles having 1 or 2 C atoms in the alkoxy moiety, especially acetonitrile and 3-methoxypropionitrile.

The reaction temperature is in general not critical and can vary within wide limits. Preferably, the reaction temperatures are between 60 and 200"C and especially between 80 and 170"C.

The compound of the formula VI or VIa which is used is preferably acrylic acid chloride or, respectively, dichloroacetyl chloride. By using these compounds the desired 2,4,4,4 - tetrahalogenobutyric acid chlorides are obtained by a direct route in the pure form and in high yields. Further preferred compounds of the formulae VI and VIa are acrylic acid and dichloroacetic acid respectively. The free 2,4,4,4 tetrahalogenobutyric acids obtained using these compounds can subsequently easily be converted in a manner known per se, to the corresponding acid chlorides by reaction with inorganic acid chlorides, such as phosphorus trichloride, phosphorus pentachloride, phosphorus oxychloride, phosgene and thionyl chloride.

The esters or nitriles of a 2,4,4,4 - tetrahalogenobutyric acid of the formula VII (Z=alkoxycarbonyl or cyano) which are obtained when compounds of the formula VI or VIa in which Z is alkoxycarbonyl or cyano are used are first hydrolysed, in the presence of strong acids, such as concentrated hydrochloric acid, to the corresponding free 2,4,4,4 - tetrahalogenobutyric acid and this is then converted to the corresponding acid chloride in the abovementioned manner.

The reaction of the 2,4,4,4 - tetrahalogenobutyric acid chlorides of the formula II with olefines of the formula III is advantageously carried out in the presence of an inert organic solvent. Suitable solvents are, for example, aromatic or aliphatic hydrocarbons, which can be halogenated, such as benzene, toluene, xylenes, chlorobenzene, dicliloro- and trichloro-benzenes, n-pentane, n-hexane, noctane, methylene chloride, chloroform, carbon tetrachloride, 1,1,2,2 - tetrachloroethane and trichloroethylene. Further suitable solvents are cycloaliphatic hydrocarbons such as cyclopentane or cyclohexane, cycloaliphatic ketones such as cyclopentanone and cyclohexanone, and also aliphatic ketones, aliphatic and cyclic ethers, alkylnitriles and 3-alkoxypropionitriles having 1 or 2 carbon atoms in the alkoxy group, especially acetonitrile and 3 methoxypropionitrile.

Particularly suitable solvents are aliphatic, cycloaliphatic and aromatic hydrocarbons, in particular alkanes having 5 to 8 carbon atoms, benzene and toluene, and especially n-hexane and cyclohexane.

However, excess olefine of the formula III can also serve as the solvent.

Suitable organic bases, in the presence of which the reaction of a 2,4,4,4 tetrahalogenobutyric acid chloride of the formula II with an olefine of the formula III is carried out, are, for example, tertiary amines, in particular trialkylamines having 1 to 4 carbon atoms, and especially 2 to 4 carbon atoms, in each alkyl group, cyclic amines, such as pyridine, quinoline, and N - alkyl - pyrrolidines, N - alkyl piperidines, N,N - dialkyl - piperazines and N- alkyl - morpholines or dialkylanilines having I or 2 carbon atoms in each alkyl group, such as N methyl - pyrrolidine, N - ethyl - piperidine, N,N' - dimethyl - piperazine, N ethyl - morpholine and N,N - dimethylaniline, and also bicyclic amidines, such as 1,5 - diazabicyclo[5.4.0] undec - 5 - ene and 1,5 - diazabicyclo[4.3.0]non - 5 - ene, and bicyclic diamines, such as 1,4 - diazabicyclo[2.2.2]octane.

The reaction of 2,4,4,4 - tetrahalogenobutyric acid chlorides of the formula II with olefines of the formula III is preferably carried out in the presence of trialkylamines having 1 to 4 carbon atoms in each alkyl group. Particularly suitable bases are triethylamine and pyridine.

The organic base is employed in at least the equimolar amount, or in a slight excess, based on the 2,4,4,4 - tetrahalogenobutyric acid chloride of the formula II.

The olefines of the formula III are likewise used in at least the equimolar amount, based on the 2,4,4,4 - tetrahalogenobutyric acid chloride of the formula II. It is, however, generally advantageous to use an excess of the olefine, in which case the olefine can, as already mentioned, also serve as the solvent. When readily volatile olefines are used, the reaction can be carried out under pressure.

The olefines of the formula III are in particular those in which one of the radicals R, and R2 is methyl and the other is hydrogen or methyl, or R, and R2 together are an alkylene group having 2 to 3 carbon atoms, i.e. isobutylene, propene, methylenecyclopropane and methylenecyclobutane. Isobutylene and methylenecyclopropane are particularly preferred.

The reaction temperatures can vary within wide limits. They are in general between 0 and 200"C and preferably between 20 and 160"C.

The 2 - (2',2',2' - trihalogenoethyl) - 2 - halogenocyclobutan - I - ones of the formula IV are also novel compounds. Catalysts which can be used for the rearrangement of the 2 - (2','',2' - trihalogenoethyl) - 2 - halogenocyclobutan 1- - ones of the formula IV, which are first obtained, into 2 - (2',2',2' - trihalogenoethyl) - 4 - cyclobutan - I - ones of the formula I are acids, bases or quaternary ammonium halides.

The rearrangement, according to the invention, of 2 - (2'.2'.2' - trihalogenoethyl) - 2 - halogenocyclobutan - I - ones of the formula IV into 2 (2',2',2' - trihalogenoethyl) - 4 - halogenocyclobutan - 1 - ones of the formula I is unexpected and is not known in the case of cyclobutanones monohalogenated in the a-position. It is particularly surprising that no elimination of HX takes place at the trihalogenoethyl group when the rearrangement is carried out in the presence of a basic catalyst. The rearrangement proceeds with excellent, and frequently quantitative, yield.

The rearrangement, according to the invention, of 2- (2',2',2' trihalogenoethyl) - 2 - halogenocyclobutan - 1 - ones of the formula IV into 2 (2',2',2' - trihalogenoethyl) - 4 - halogenocyclobutan - I - ones of the formula I is preferably carried out in the presence of basic catalysts. The basic catalysts are organic bases, such as primary, secondary and especially tertiary amines of the formula

in which Q1 is alkyl having I to 8 carbon atoms, cycloalkyl having 5 to 6 carbon atoms, benzyl or phenyl and Q2 and Q3 independently of one another are hydrogen or alkyl having I to 8 carbon atoms. Suitable basic catalysts are, for example, triethylamine, tri-n-butylamine, tri-isopentylamine, tri-n-octylamine, N,N dimethylcyclohexylamine, N,N - dimethylbenzylamine, N,N - dimethyl - 2ethylhexylamine, N,N - diethylaniline and also cyclic amines, such as pyridine, quinoline, lutidine, N-alkylmorpholines, such as N-methylmorpholines. Nalkylpiperidines, such as N-methyl- and N-ethyl-piperidine, N-alkyl-pyrrolidines, such as N-methyl- and N-ethyl-pyrrolidine, diamines, such as N,N,N',N'tetramethylethylenediamine and N,N,N',N' - tetramethyl - 1,3 - diaminobutane, N,N' - dialkylpiperazines, such as N,N' - dimethylpiperazine, bicyclic amines, such as 1,4 - diazabicyclo[2.2.2]octane, and bicyclic amidines; such as 1,5 diazabicyclo[5.4.Oiundec - 5 - ene and 1,5 - diazabicyclot4.3.0]non - 5 - ene, and finally polymeric basic compounds, such as p - dimethylaminomethylpolystyrene.

Further suitable basic catalysts for the rearrangement, according to the invention, of a 2 - (2',2',2' - trihalogenoethyl) - 2 - halogenocyclobutan - I - one of the formula IV into a 2 - (2',2',2' - trihalogenoethyl) - 4 - halogenocyclobutan 1 - one of the formula I are phosphines, especially trialkylphosphines, for example tributylphosphine.

Acid catalysts which can be used for the rearrangement of 2 - (2',2',2' trihalogenoethyl) - 2 - halogenocyclobutan - I - ones of the formula IV into 2 (2',2',2' - trihalogenoethyl) - 4 - halogenocyclobutan - 1 - ones of the formula I are inorganic or organic proton acids. Suitable inorganic proton acids are, for example, hydrogen halide acids, such as hydrogen chloride, hydrogen bromide, hydrogen fluoride and hydrogen iodide, nitric acid, phosphoric acid and sulphuric acid. Preferred inorganic proton acids are hydrogen halide acids.

If acids or bases are employed in excess, they can also serve as solvents.

Furthermore, salts of proton acids, especially hydrogen halide acids, with ammonia or a nitrogen-containing organic base, and also quaternary ammonium halides, quaternary phosphonium halides and sulphonium halides can be employed. Suitable nitrogen-containing organic bases are aliphatic, cycloaliphatic.

araliphatic and aromatic primary, secondary and tertiary amines, as well as heterocyclic nitrogen bases. Examples are: primary aliphatic amines having up to 12 C atoms, such as methylamine, ethylamine, n-butylamine, n-octylamine, n dodecylamine, hexamethylenediamine, cyclohexylamine and benzylamine: secondary aliphatic amines having up to 12 C atoms, such as dimethylamine, diethylamine, di-n-propylamine, dicyclohexylamine, pyrrolidine, piperidine, piperazine and morpholine: tertiary aliphatic amines, especially trialkylamines having 1-4 C atoms in each alkyl moiety, such as triethylamine, tri-n-butylamine, N-methylpyrrolidine, N-methylmorpholine, 1,4 - diazabicyclo[2.2.2]octane and quinuclidine: substituted or unsubstituted primary, secondary and tertiary aromatic amines, such as aniline, toluidine, naphthylamine, N-methylaniline, diphenylamine and N,N-diethylaniline; and also pyridine, picoline, indoline and quinoline.

Quaternary phosphonium halides which can be used are, for example: hexadecyltributylphosphonium bromide and methyl- and ethyltriphenylphosphonium bromide; and a sulphonium halide which can be used is, for example, trimethylsulphonium iodide.

Preferred salts are those of the formula

in which M is fluorine, bromine or iodine and especially chlorine, Q4 is hydrogen, alkyl having 1--18 C atoms, cyclohexyl, benzyl, phenyl or naphthyl and Q5, Q6 and Q7 independently of one another are hydrogen or alkyl having 1--18 C atoms, and also N-alkyl-pyridinium halides having 1--18 C atoms in the alkyl, especially the corresponding chlorides.

Examples of such salts are: ammonium chloride, ammonium bromide, methylamine hydrochloride, cyclohexylamine hydrochloride, aniline hydrochloride, dimethylamine hydrochloride, di-isobutylamine hydrochloride, triethylamine hydrochloride, triethylamine hydrobromide, tri-n-octylamine hydrochloride, benzyl-dimethylamine hydrochloride, tetramethylammonium chloride, bromide and iodide, tetraethylammonium chloride, bromide and iodide, tetra-n-propylammonium chloride, bromide and iodide, tetra-n-butylammonium chloride, bromide and iodide, trimethyl-hexadecylammonium chloride, benzyldimethylhexadecylammonium chloride, benzyldimethyltetradecylammonium chloride, benzyl - trimethyl-, -triethyl- and -tri - n- butylammonium chloride, n - butyl tri - n - propylammonium bromide, octadecyltrimethylammonium bromide, phenyltrimethylammonium bromide or chloride and hexadecylpyridinium bromide and chloride.

Additional co-catalysts which can be used are alkali metal halides, such as potassium iodide, sodium iodide, lithium iodide, potassium bromide, sodium bromide, lithium bromide, potassium chloride, sodium chloride, lithium chloride, potassium fluoride, sodium fluoride and lithium fluoride.

These co-catalysts catalyse the reaction even in the absence of the above ammonium salts, but additions of open-chain or macrocyclic polyethers (crown ethers) are then advantageous for a rapid course of reaction. Examples of such crown ethers are: 15-crown-5, 18-crown-6, dibenzo - 18 - crown 6, dicyclohexyl - 18 - crown - 6, 5,6,14,15 - dibenzo - 7,13 - diaza - 1,4 - dioxa cyclopentadeca - 5,14 - diene.

The amount of catalyst employed can vary within wide limits. In some cases it suffices if the catalyst is present in traces. In general, however, the catalyst is preferably employed in an amount of 0.1 to 15 percent by weight, based on the compound of the formula YI.

The rearrangement can be carried out either in the melt or in an inert organic solvent. The reaction temperatures for the rearrangement in the melt are in general between 60 and 1500C and especially 80 to 1300C.

Suitable catalysts for the rearrangement in the melt are, in particular, the abovementioned organic bases, especially trialkylamines having 1-8 C atoms in each alkyl moiety: and also salts of hydrogen halide acids with ammonia or organic nitrogen-containing bases, such as trialkylamine hydrochlorides and hydrobromides having 1-8 C atoms in each alkyl moiety, and very particularly tetraalkylammonium halides, in particular tetraalkylammonium chlorides, bromides and iodides, having 1--18 C atoms in each alkyl moiety.

Examples of suitable inert organic solvents are aliphatic, cycloaliphatic or aromatic hydrocarbons, which can be nitrated or halogenated, such as n-hexane. npentane, cyclohexane, benzene. toluene, xylenes. nitrobenzene. chloroform.

carbon tetrachloride, trichloroethylene, 1.1,2,2 - tetrachloroethane, nitromethane, chlorobenzene, dichlorobenzenes and trichlorobenzenes: lower aliphatic alcohols.

for example those having up to 6 C atoms, such as methanol, ethanol, propanol.

isopropanol, butanols and pentanols; aliphatic diols. such as ethylene glycol and diethylene glycol: ethylene glycol monoalkyl ethers and diethylene glycol monoalkyl ethers having, in each case, 1--4 C atoms in the alkyl moieties, such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether, diethylene glycol monomethyl ether and diethylene glycol monoethyl ether; cyclic amides, such as N - methyl - 2 - pyrrolidone, N - acetyl - 2 - pyrrolidone and N methyl - E - caprolactam; amides of carbonic acid, such as tetramethylurea and dimorpholinocarbonyl; amides of phosphorous acid, of phosphoric acid, of phenylphosphonic acid or of aliphatic phosphonic acids having 1-3 C atoms in the acid moiety, such as phosphoric acid triamide, phosphoric acid tris (dimethylamide), phosphoric acid trimorpholide, phosphoric acid tripyrrolinide, phosphoric acid bis - (dimethylamide) -. morpholide, phosphoric acid dimethylamide - diethylamide - morpholide, phosphorous acid tris (dimethylamide) and the tetramethyldiamide of methanephosphonic acid; amides of sulphuric acid and of aliphatic or aromatic sulphonic acids, such as tetramethylsulphamide, the dimethylamide of methanesulphonic acid or ptoluenesulphonic acid amide; sulphur-containing solvents, such as organic sulphones and sulphoxides, for example dimethylsulphoxide and sulpholane: and aliphatic and aromatic nitriles, 3-alkoxypropionitriles, aliphatic ketones, alkyl and alkoxyalkyl esters of aliphatic monocarboxylic acids, cyclic ethers, dialkyl 'ethers, N,N-disubstituted amides of aliphatic monocarboxyiic acids and ethylene glycol dialkyl ethers and diethylene glycol dialkyl ethers of the type mentioned under process stage 1).

For the rearrangement in the presence of an acid catalyst, polar solvents are advantageously used, especially lower alcohols, such as methanol, ethanol and butanols, N,N-dialkylamides of aliphatic monocarboxylic acids having 1-3 C atoms in the acid moiety, especially N,N-dimethylformamide, or dialkylsulphoxides, such as dimethylsulphoxide.

In aprotic, strongly polar solvents, such as the abovementioned N,Ndisubstituted amides of aliphatic monocarboxylic acids, cyclic a of the formula III, a 2 - (2',2',2' - trihalogenoethyl) - 2 - halogenocyclobutan - I one of the formula IV, which is unsuitable for further conversion into a 2 - (2',2' dihalogenovinyl) - cyclopropanecarboxylic acid derivative substituted in the 3position, is first formed and this is then converted, by a novel rearrangement, not hitherto observed in the case of cyclobutanones, monohalogenated in the aposition, into a 2 -(2',2',2' - trihalogenoethyl) - 4 - halogenocyclobutan - I - one of the formula I, which is suitable for further conversion into a 2 - (2',2' dihalogenovinyl) - cyclopropanecarboxylic acid derivative substituted in the 3position.

The 2 - (2',2' - dihalogenovinyl) - cyclopropanecarboxylic acids substituted in the 3-position, and their esters having an insecticidal action, which can be prepared using novel 2 - (2',2',2' - trihalogenoethyl) - 4 - chlorocyclobutan - I ones of the formula I as the starting materials, can be described by the following formula VIII:

in which X, R1 and R2 are as defined under formula I and R is hydrogen, alkyl having I to 4 carbon atoms or a group of the formula IX

in which R3 is oxygen, sulphur or a vinylene group, R4 is hydrogen, alkyl having I to 4 carbon atoms, benzyl, phenoxy or phenylmercapto, R5 is hydrogen or an alkyl group having I to 4 carbon atoms and R5 is hydrogen, cyano or ethynyl, or, if one of the radicals R1 and R2 is methyl and the other is hydrogen or methyl, R3 is the vinylene group, R4 is phenoxy and R5 is hydrogen, also alkyl having I to 5 carbon atoms.

The 2 - (2',2' - dihalogenovinyl) - cyclopropanecarboxylic acid derivatives of the formula VIII in which R is a group of the formula IX are suitable for combating diverse animal on plant pests, especially insects. The properties, fields of application and use forms of these active compounds are described in the literature (c.f., for example, Nature, 246, 169-170 (1973); Nature, 248, 710711 (1974); Proceedings 7th British Insecticide and Fungicide Conference, 721-728 (1973); Proceedings 8th British Insecticide and Fungicide Conference, 373-78 (1975); J.

Agr. Food Chem. 23, 115 (1973): U.S. Patent Specification 3,961,070; and German Offenlegungsschriften 2,553,991, 2,439,177, 2,326,077 and 2,614,648).

The conversion of 2 - (2',2',2' - trihalogenoethyl) - 4 - halogenocyclobutan - - ones of the formula I into 2 - (2',2' - dihalogenovinyl) cyclopropanecarboxylic acid derivatives of the formula VIII is carried out in a manner known per se, by heating in the presence of suitable bases. Examples of suitable bases are alkali metal hydroxides and alkaline earth metal hydroxides, such as sodium hydroxide, potassium hydroxide, calcium hydroxide and barium hydroxide. Alkali metal carbonates and bicarbonates and alkaline earth metal carbonates and bicarbonates, such as calcium carbonate, barium carbonate, potassium carbonate, sodium carbonate, sodium bicarbonate and potassium bicarbonate, can also be used as bases. Further suitable bases are alcoholates derived from the radical R according to the above definition, especially the corresponding sodium alcoholates and potassium alcoholates. The use of such alcoholates has the advantage that the corresponding ester is obtained direct, whilst when alkali metal hydroxides and alkaline earth metal hydroxides are used, the salts of these bases with the 2 - (2',2' - dihalogenovinyl) cyclopropanecarboxylic acid formed are first obtained. These salts can, however, also be converted into esters in a simple manner which is known per se, for example by converting them into the corresponding acid chloride and reacting the latter with an alcohol derived from the radical R.

Depending on the nature of the base used, the conversion of a 2 (2t - (2',2',2' - trihalogenoethyl) - 4 - halogenocyclobutan - i - one of the formula I into a 2 (2',2' - dihalogenovinyl) - cyclopropanecarboxylic acid derivative of the formula VIII is advantageously carried out in an aqueous, aqueous-organic or organic medium. When the base used is an alkali metal carbonafe or alkaline earth metal carbonate, the reaction is carried out in an aqueous or aqueous-organic medium.

The reaction in the presence of alkali metal hydroxides or alkaline earth metal hydroxides and alkali metal bicarbonates is also advantageously carried out in an aqueous or aqueous-organic medium. In this case, the free 2 - (2',2' dihalogenovinyl) - cyclopropanecarboxylic acids of the formula VIII (R=H) are obtained after acidifying the reaction mixture, for example by adding concentrated hydrochloric acid.

Suitable solvents for the conversion of 2 - (2',2',2' - trihalogenoethyl) - 4 halogenocyclobutan - I - ones of the formula I into 2 - (2',2' - dihalogenovinyl) cyclopropanecarboxylic acid derivatives of the formula VIII in an aqueous-organic or organic medium are lower alcohols, for example those having I to 6 carbon atoms, benzyl alcohol, aliphatic or cyclic ethers, such as diethyl ether, di-n-propyl ether, diisopropyl ether, tetrahydrofurane and dioxane, and also aliphatic, cycloaliphatic or aromatic hydrocarbons, such as n-pentane, n-hexane, cyclohexane, benzene, toluene and xylenes.

The conversion of 2 - (2',2',2' - trihalogenoethyl) - 4 - halogenocyclobutan I - ones of the formula I to 2 - (2',2' - dihalogenovinyl) --cyclopropanecarboxylic acid derivatives of the formula VIII is generally carried out at the boiling point of the reaction medium chosen. Reaction temperatures of between 40 and 1200C are particularly suitable.

When 2 - (2',2',2' - trihalogenoethyl) - 4 - halogenocyclobutan - I - ones of the formula I are converted into 2- (2',2' - dihalogenovinyl)cyclopropanecarboxylic acid derivatives of the formula VIII, the corresponding 2 (2',2',2' - trihalogenoethyl)- cyclopropanecarboxylic acid derivatives of the formula X

in which R, R,, R2 and X are as defined, are formed as intermediates. These products can be isolated if the reaction temperature is kept below 40"C and/or a less than equivalent amount of base is used. Above 40"C, these intermediates are converted to the corresponding 2 - (2',2' - dihalogenovinyl) cyclopropanecarboxylic acid derivatives of the formula VIII on the addition of further base, with the elimination of HX.

The 2 - (2',2',2' - trihalogenoethyl) - cyclopropanecarboxylic acid derivatives of the formula X can also be prepared photo-chemically from 2 - (2',2',2' trihalogenoethyl) - 4 - halogenocyclobutan - 1 - ones of the formula I, by irradiation with UV light, if necessary with the addition of conventional sensitisers (for example ketones, such as acetone, cyclohexanone, benzophenone, acetophenone and higher alkylaryl ketones and thioxanthone), in the presence of reagents containing hydroxyl groups, which at the same time can serve as solvents.

Examples of reagents containing hydroxyl groups are alkanols, such as methanol and ethanol, and in particular water.

The process according to the invention is illustrated in more detail by the following examples.

Example 1 a) Preparation of 2,4,4,4-tetrachlorobutyric Acid Chloride 452.5 g (5 mols) of acrylic acid chloride (technical grade purity), 1.5 litres of carbon tetrachloride, 1.5 litres of acetonitrile and 30 g of copper-I chloride are kept at 11 50C for 24 hours. The reaction mixture is filtered to give a clear filtrate and the latter is evaporated under a waterpump vacuum. The residue is distilled. This gives 922 g (760o of theory) of 2,4,4,4 - tetrachlorobutyric acid chloride; boiling point 78-800C/ll mm Hg.

IR spectrum (CHC13) in cm-': 1780 (C=0).

NMR spectrum (100 MHz, CDCI3) in ppm: 3.16-3.94 (m, 2H, CH2); 4.84 4.96 (m, 1H, CH).

2,4,4,4 - Tetrachlorobutyric acid chloride can also be prepared as follows: 90.5 g (1 mol) of acrylic acid chloride, 0.5 litre of carbon tetrachloride, 0;2 litre of butyronitrile and 3 g of copper powder are heated at 1150C for 20 hours. The reaction mixture is filtered, the filtrate is evaporated and the residue is distilled.

This gives 167.8 g (69 -ó of theory) of 2,4,4,4 - tetrachlorobutyric acid chloride; melting point: 80--81"C/12 mm Hg. The spectroscopic data are identical to those of the 2,4,4,4 - tetrachlorobutyric acid chloride prepared according to paragraph I.

If the copper powder is replaced by copper-I chloride and the butyronitrile is replaced by 3-methoxypropionitrile and the procedure is otherwise identical, 2,4,4,4 - tetrachlorobutyric acid chloride is obtained in a yield of 71% of theory.

226 g ( I mol) of 2,4,4,4 - tetrachlorobutyric acid [prepared in accordance with Israeli Patent Specification 18,771=CA, 63, 13089e (1965)], 600 g of thionyl chloride and I ml of N,N-dimethylformamide are warmed at 50 C for 2 hours and at 750C for 2 hours. After evaporating off the excess thionyl chloride, the residue is distilled. This gives 227.6 g (93 ZÓ of theory) of 2,4,4,4 - tetrachlorobutyric acid chloride; boiling point 90-91 C/15 mm Hg.

145.9 g (1.5 mols) of l,l-dichloroethylene, 147.4 g (1 mol) of dichloroacetyl chloride, 200 ml of acetonitrile and 3 g of copper-I chloride are heated at 1 300C for 8 hours. The reaction mixture is evaporated and the residue is subjected to fractional distillation. This gives 2,4,4,4 - tetrachlorobutyric acid chloride in the form of a colourless liquid; boiling point 78-800C/l I mm Hg. The spectroscopic data of the substance obtained are identical to those of the 2,4,4,4 - tetrachlorobutyric acid chloride prepared according to paragraph 1.

b) Preparation of 2-chloro-2-(2',2',2'-trichloroethyl)-3,3-dimethylcyclobutan-1-one 280 g of isobutylene are injected into 122 g (0.5 mol) of 2,4,4,4 tetrachlorobutyric acid chloride in 600 ml of cyclohexane, in an autoclave. A solution of 51 g (0.5 mol) of triethylamine in 500 ml of cyclohexane is pumped in at 65 C in the course of 4 hours. The reaction mixture is then kept at 650C for a further 3 hours. The hydrochloride of triethylamine, which has precipitated, is filtered off and the filtrate is evaporated. The crystals thus obtained are filtered off.

This gives 79.4 g (600/0! of theory) of 2 - chloro - 2 - (2',2',2' - trichloroethyl) - 3,3 dimethylcyclobutan - I - one with a melting point of 75--76"C.

IR spectrum (CHCl3) in cm-': 1805 (C=0).

'H NMR spectrum (100 MHz, CDCl3) in ppm: 1.42 and 1.45 (in each case 1 s, 6H and in each case I CH3); 2.91-3.28 (m, 2H, CH2); 3.37-3.76 (m, 2H, CH2).

13C NMR spectrum (CDCl3) in ppm: 196 (s, CO); 95.3 (s, CH3); 80.8 (s, C-2); 57.0 (t, CH2); 56.4 (t, CH2); 37.9 (s, C-3); 25.1 (q, CH3); 28.8 (q, CH3).

Elementary analysis for C8HloCl4O (molecular weight 263.98): calculated C 36.40 só H 3.82%, 0 6.02% Cl 53.72% found C 36 4% H 3.9% 0 6.2% Cl 53.5 Ó.

c) Preparation of 2-(2' 2' ,2'-trichloroethyl)-3 ,3-dimethyl-4-chlorocyclobutan- 1 one 132 g (0.5 mol) of the resulting 2 - chloro - 2 - (2',2',2' - trichloroethyl) - 3,3 dimethylcyclobutan - I - one are dissolved in 700 ml of toluene, 1 ml of triethylamine is added and the mixture is boiled under reflux. After a reaction time of 13 hours, a further 1 ml of triethylamine is added and the mixture is boiled for a further 7 hours. After cooling, the reaction mixture is washed, first with dilute hydrochloric acid and then with water, dried and evaporated. the solidified residue (124 g: 940o of theory), which according to thin layer chromatography is a single compound, is crystallised from n-hexane. This gives 105.8 g of 2 - (2',2',2' trichloroethyl) - 3,3 - dimethyl - 4 - chlorocyclobutan - I - one: melting point 56--57"C IR spectrum (CHCl3) in cm-': 1800 (C=0).

'H NMR spectrum (100 MHz, CDCI3) in ppm: 4.77 (d, J=2 Hz, 1H, H on C-4): 3.47 (m, lH, H on C-2): 2.73-3.26 (m, 2H, CH2): 2.63 (s, 3H, CH3); 1.14 (s, 3H, CH3).

'3C-NMR spectrum (CDC13) in ppm: 197.0 (s, CO): 97.8 (s, CC1,): 69.4 (d, C-4): 60.6 (d, C-2); 49.5 (t, CH2-CCl3): 36.8 (s, C-3): 27.4 (q, CH3): 18.6 (q. CH).

Elementary analysis for CsH10Cl4O (molecular weight 263.98): calculated C36.40q, H 3.82% O 6.02 " Cl 53.720o found C 36.6, ó H 3e8 ö 0 6.2% Cl 53.6%.

The above compound can also be prepared as follows: 2.64 g (0.01 mol) of 2 chloro - 2 - (2',2',2' - trichloroethyl) - 3,3 - dimethylcyclobutanone and 220 mg (0.0008 mol) of tetra-n-butylammonium chloride are stirred for 6.5 hours at 124 C.

The cooled melt is boiled up with hot n-hexane and filtered to give a clear filtrate.

As the filtrate cools, 2.19 g (83,ó of theory) of 2 - (2',2',2' - trichloroethyl) - 3,3 dimethyl - 4 - chlorocyclobutanone with a melting point of 53-56 C precipitate.

d) Preparation of 2-(2',2'-dichlorovinyl)-3,3-dimethylcyclopropane- I -carboxylic Acid 13.2 g (0.05 mol) of 2 - (2',2',2' - trichloroethyl)- 3,3 - dimethyl - 4 chlorocyclobutan - I - one are added to 150 ml of 10% strength sodium hydroxide solution and the mixture is stirred intensively. After 5 minutes a clear solution has formed and this is warmed at 100 C (bath temperature) for I hour. The reaction solution is washed with diethyl ether, acidified with concentrated hydrochloric acid, with cooling, and extracted with diethyl ether. The ether phase is washed with water, dried over magnesium sulphate and evaporated. According to the NMR spectrum, the solid residue (10.35 g) consists of 80 só by weight of cis - 2 - (2',2' dichlorovinyl) - 3,3 - dimethylcyclopropane - I - carboxylic acid and 200 by weight of trans - 2 - (2',2' - dichlorovinyl) - 3,3 - dimethylcyclopropane - I carboxylic acid. Crystallisation from n-hexane gives the pure cis-acid; melting point 85--87"C.

IR spectrum (CHCl3) in cm-': 1710 (CO), 1625 (C=C).

NMR spectrum (100 MHz, CDCI3/D20) in ppm: 1.30 (s, 6H, 2xCH3); 1.85 (d, J=8.5 Hz, 1H, HC-I); 2.02-2.19 (m, 1H, HC-2); 6.17 (d, J=8 Hz, 1H, CH=CCl2).

Example 2 421 g of propylene, 244 g (1 mol) of 2,4,4,4 - tetrachlorobutyric acid chloride and 1.25 litres of cyclohexane are initially-introduced into a 6.3 litre autoclave. A solution of 101 g (1 mol) of triethylamine in I litre of cyclohexane is pumped in at 50 C in the course of 4 hours and the reaction mixture is then kept at 50 C for 3 hours. The reaction mixture is filtered and the resulting filtrate is washed with dilute hydrochloric acid and then with water, dried over magnesium sulphate and evaporated. The residue is crystallised from n-hexane. This gives 77.2 g of 2 chloro - 2 - (2',2',2' - trichloroethyl) - 3 - methylcyclobutan - I - one; melting point 80--81"C.

IR spectrum (CHCl3) in cm-': 1785 (CO).

'H NMR spectrum (100 MHz, CDCI3) in ppm: 3.28-3.73 (m, 3H); 2.65-2.95 (m, 2H); 1.43 (d, J=6.5 Hz, 3H, CH3).

13C NMR spectrum (CDCl3) in ppm: 196.5 (s, CO); 95.1 (s, CCI3); 77.8 (s, C-2); 55.3 (t, CH2-CCl3); 50.9 (t, C-4); 38.1 (d, C-3); 15.8 (q, CH3).

1 ml of triethylamine is added to 50 g (0.2 mol) of the resulting 2 - chloro - 2 (2',2',2' - trichloroethyl) - 3 - methylcyclobutan - I - one in 500 ml of toluene and the mixture is stirred for 18 hours at a bath temperature of 1200C. After cooling, the reaction mixture is filtered to give a clear filtrate and the filtrate is washed, first with dilute hydrochloric acid and then with water, boiled up briefly with active charcoal, filtered again and evaporated. Distillation of the residue gives 38.7 g (77 " of theory) of 2 - (2',2',2' - trichloroethyl) - 3 - methyl - 4 - chlorocyclobutan I - one; boiling point 130-131 C/12 mm Hg.

IR spectrum (CHCl3) in cm-': 1805 (CO).

NMR spectrum (100 MHz, CDCl3) in ppm: 1.20 (d, 5=7 Hz, 0.6H, CH3): 1.46 (d, 5=7 Hz, 0.45H, CH3); 1.66 (d, J=6.5 Hz, 1.95H, CH3); 2.1-3.5 (m, 4H); 4.55 (dd, J=8 and 2 Hz, 0.65H, CH); 5.00 (dd, J=9 and 2.5 Hz, 0.15H, CH): 5.15 (dd, J=9 and 1.5 Hz, 0.2H, CH).

According to the NMR spectrum and the gas chromatogram, the compound consists of 3 stereoisomers in a weight ratio of 13:4:3.

10.5 g of the resulting 2 - (2',2',2' - trichloroethyl)- 3 - methyl - 4 chlorocyclobutan - 1 - one are stirred with 100 ml of 10?, strength sodium hydroxide solution for 50 minutes. The solution which has formed is then heated at 100 C for 1 hour. The reaction mixture is then washed with diethyl ether and carefully acidified with concentrated hydrochloric acid. It is then extracted with diethyl ether. The ether extract is washed with water, dried over magnesium sulphate and evaporated. This gives 2 - (2',2' - dichlorovinyl)- 3 methylcyclopropane - 1 - carboxylic acid; melting point 75--78"C (recrystallised from n-hexane).

IR spectrum (KBr) in cam~': 1685 (C=O), 1625 (C=C).

NMR spectrum (100 MHz, CDClD2O) in ppm: 1.25 (d, J=5.5 Hz, 3H, CH3); 1.54-2.18 (m, 3H); 3.96 (d, J=8 Hz, 1H, CH-CCl2).

Example 3 A solution of 25.3 g (0.25 mol) of triethylamine in 50 ml of n-hexane is addeddropwise, in the course of 7 hours, with stirring, to a solution, which is kept under reflux, of 25 g (0.37 mol) of methylenecyclobutane and 61.1 g (0.25 mol) of 2,4,4,4 tetrachlorobutyric acid chloride in 200 ml of n-hexane. After the reaction mixture has been stirred under reflux for a further 2 hours, it is freed, whilst still hot, from the ammonium salt formed, by filtration. The filtrate is concentrated to about 1/3rd its volume. On cooling, I - chloro - 1 - (2',2',2' - trichloroethyl) spirof3.31heptan - 2 - one of the formula

precipitates in a crystalline form; melting point 93--94"C.

IR spectrum (CCl4) in cm-': 1790 (C=O).

NMR spectrum MHz, CDCl3) in ppm: 1.70-2.80 (m, 6H); 3.15-3.60 (m, 4H).

A solution of 27.6 g (0.1 mol) of the resulting 1 - chloro - I - (2',2',2' trichloroethyl)spiro[3.3]heptan - 2 - one in 100 ml of toluene, together with 0.93 g (5 mmols) of tributylamine, is refluxed for 9 hours. The reaction mixture is then evaporated and the residue is distilled in vacuo. This gives 1 - chloro - 3 (2',2',2' - trichloroethyl)spiro[3.3]heptan - 2 - one of the formula

in the form of a slightly yellowish oil; boiling point 85-900C/0.005 mm Hg; n0=1.5242.

IR spectrum (film) in cm-l: 1795 (C=O).

NMR spectrum (100 MHz, CDCI3) in ppm: 1.803.85 (m, 9H); 4.68, 4.93 (each one d, together 1 H).

11.0 g (40 mmols) of the resulting I - chloro - 3 - (2',2',2' trichloroethyl)spiro[3.3lheptan - 2 - one are stirred together with 95 ml (about 240 mmols) of 10% strength sodium hydroxide solution for 6 hours at 950C. After cooling, the mixture is washed with several portions of diethyl ether, acidified with sulphuric acid and extracted with diethyl ether. The ether extracts are evaporated after drying over sodium sulphate. A small amount of strongly polar impurities is eliminated by filtering the residue from ten times the amount by weight of silica gel (eluant n-hexane/diethyl ether in a volume ratio of 1:1). After concentrating the filtrate, 2 - (2',2' - dichlorovinyl)spiro[2.3]hexane - I - carboxylic acid of the formula

is obtained in the form of a 2:1 cis/trans mixture; melting point 121--28"C.

IR spectrum (CCl4) in cm~1: 1705 (C=O).

NMR spectrum (100 MHz, CDCI3) in ppm: 1.602.60 (m. 8H); 5.34. 5.97 (each one d, together lH); 11.80--11.50 (broad s, IH).

Example 4 280 g of isobutylene are injected into 122 g (0.5 mol) of 2,4,4,4 - tetrachlorobutyric acid chloride in 600 ml of cyclohexane, in an autoclave. SI g(0.5 mol) of triethylamine in 500 ml of cyclohexane are pumped in at 650C in the course of 4 hours. The reaction mixture is then kept at 65"C for 3 hours and then heated at 125"C for 18 hours. During this time, 2.0 g of triethylamine in 50 ml of cyclohexane are pumped in every 3 hours. The reaction mixture is poured onto ice. acidified with hydrochloric acid and extracted with cyclohexane. The evaporated extract is filtered in toluene/cyclohexane (1:1 mixture by volume) through 1 kg of silica gel in order to remove strongly polar impurities. The filtrate is evaporated and the residue is crystallised from n-hexane. This gives 31.8 g of 2 - (2','','' trichloroethyl) - 3,3 - dimethyl - 4 - chlorocyclobutan - I - one: melting point 56--57"C.

Example 5 a) 26.1 g (99 mmols) of 2 - (2',2',2' - trichloroethyl) - 3.3 - dimethyl - 4 chlorocyclobutanone are added to 260 ml of a 10 o strength sodium hydroxide solution, at 11 C, with stirring. The temperature rises to 280C in the course of 2.4 hours and then falls to 200C in the course of a further 2 hours. The reaction mixture is diluted with 200 ml of water, washed with diethyl ether, rendered strongly acid with concentrated hydrochloric acid and extracted with diethyl ether. The extract is washed with water, dried over magnesium sulphate and evaporated. This gives 24.3 g (100 ,ó of theory) of a pale yellow residue (melting point 8()-810C), which consists exclusively of cis- and trans - 2 - (2',2',2' - trichloroethyl) - 3,3 dimethylcyclopropanecarboxylic acid. The mixture can be separated into the pure cis and trans compounds by fractional crystallisation or by column chromatography.

NMR spectrum (100 MHz, CDCI3/D2O) in ppm: 2.75-3.33 (m, 2H): 1.50-- 1.97 (m, 2H): 1.32 (s, 2xCH3 cis); 1.27 and 1.38 (2xs, 2xCH3 trans).

b) 8.0 g (30.3 mmols) of 2 - (2',2',2' - trichloroethyl) - 3,3 - dimethyl - 4 chlorocyclobutanone in 400 ml of acetone and 100 ml of water are irradiated, through Pyrex glass, with a Philips HPK 125 watt lamp until no further starting material can be detected by chromatography (the words Pyrex and Philips are Registered Trade Marks). The reaction mixture is evaporated and the residue is worked up to the acid as indicated under a). This gives 6.95 g (93 O of theory) of a cis/trans mixture of 2 - (2',2',2' - trichloroethyl) - 3,3 dimethylcyclopropanecarboxylic acid, the spectroscopic data of which are identical to those of the mixture obtained according to a).

c) 24.55 g (0.1 mol) of 2 - (2',2',2' - trichloroethyl) - 3,3 dimethylcyclopropanecarboxylic acid are suspended in 350 ml of 10 " strength sodium hydroxide solution and the suspension is stirred for 4.5 hours at a bath temperature of 100"C. The reaction solution is washed with diethyl ether, acidified with hydrochloric acid and extracted with chloroform. The extract is washed with water, dried over magnesium sulphate and evaporated. After crystallisation from nhexane, 17.55 g (84% of theory) of colourless 2 - (2',2' - dichlorovinyl) - 3,3 dimethylcyclopropanecarboxylic acid are obtained.

Example 6 145 g (0.5 mol) of 2 - bromo - 4,4,4 - trichlorobutyric acid chloride, 280 g (5 mols) of isobutylene and 600 ml of cyclohexane' are initially introduced into an autoclave. 51 g (0.5 mol) of triethylamine in 500 ml of cyclohexane are pumped in at 65"C in the course of 4 hours. The mixture is then stirred for a further 3 hours at this temperature. The reaction mixture is filtered. The filtrate is evaporated and the residue is crystallised from n-hexane. This gives 74.5 g (48?( of theory) of 2 bromo - 2 - (2',2',2' - trichloroethyl) - 3,3 - dimethylcyclobutanone in the form of a light beige powder; melting point 4649"C.

IR spectrum (CHCl3) in cm-l: 1885 (CO).

'H NMR spectrum (100 MHz, pyridine-d5) in ppm: 3.79 (AB, 2H, CH2): 3.10 (AB, 2H, Cm2): 1.37 and 1.42 (Is in each case, total 6H, CH3 in each case).

13C NMR spectrum (CDCl3) in ppm: 196.8 (CO): 95.6 (CCI,); 74.8 (C-2): 56.5 and 56.3 (CH2 in each case): 38.0 (C-3); 27.4 and 24.7 (CH3 in each case).

20 g (0.065 mol) of 2 - bromo - 2- (2',2',2' - trichloroethyl)- 3,3 dimethylcyclobutanone and 5 g of tetrabutylammonium bromide are stirred for 30 minutes at 800C and for 10 minutes at 1000C. The solidified melt is chromatographed on silica gel (elution with toluene/cyclohexane, 1:1). 2 (2's2'.'' - Trichloroethyl) - 3,3 - dimethyl - 4- bromocyclobutanone, which crystallises on standing, is obtained in this way: melting point 56"C.

'H NMR spectrum (100 MHz, CDCI3) in ppm: 4.99 (d, J=2 Hz, 1H, H on 3.58 (X moiety ofABX, additionally resolved with J=2 Hz, 1H, H on C-2); 3.05 (AB moiety of ABX, 2H, CH2); 1.22 and 2.67 (its in each case, 3H in each case, CH3 in each case).

t3C NMR spectrum (CDCl3) in ppm: 196.7 (s, CO): 97.7 (s, CC13): 60.7 (d, C-2); 59.8 (d, C-4): 50.0 (t CH2-CCl3); 36.4 (s, C-3); 27.6 (q,

IR spectrum (CHCl3) in cm-': 1695 (CO).

NMR spectrum (100 MHz, CDCI3/D2O) in ppm: 6.70 (6d. 5=8 Hz. 1H, CH CBr2); 1.82-2.14 (m, 2H): 1.30 and 1.33 (Is in each case, total 6H, CH3 in each case).

Example 8 10.1 g (0.1 mol) of triethylamine in 100 ml of cyclohexane are added dropwise in the course of 2 hours, at 650C, to a solution of 14 g (0.17 mol) or methylenecyclopentane and 26.4 g (0.1 mol) of 2,4,4,4 - tetrachlorobutyric acid chloride in 220 ml of cyclohexane, with stirring. The mixture is then stirred at this temperature for a further 3 hours. The reaction mixture is washed with dilute hydrochloric acid and then with water, dried over magnesium sulphate and evaporated. The residue is crystallised from n-hexane. This gives 16.6 g of 1 chloro - I - (2',2',2' - trichloroethyl)spiro[3.4]octan - 2 - one of the formula

melting point 7073 C.

IR spectrum (CHCl3) in cm-1: 1775 (CO).

NMR spectrum (100 MHz, CDCI3) in ppm: 1.60-2.30 (m, 8H); 3.08 (AB, 2H, CH2); 3.60 (AB, 2H, CH2).

12.0 g (0.041 mol) of I - chloro - 1 - (2',2',2' - trichloroethyl)spirol3.4]octan 2 - one are stirred with 3.6 g of tetrabutylammonium chloride at a bath temperature of 125 C. After 1.5 hours, the reaction mixture is chromatographed on silica gel (elution with toluene/cyclohexane, 1:1). 9.7 g (81 /ó of theory) of I chloro - 3 - (2',2',2' - trichloroethyl)spiro[3.4]octan - 2 - one of the formula

are obtained in this way in the form of a colourless oil.

IR spectrum (CHCl3) in cm~1: 1800 (CO).

NMR spectrum (100 MHz, CDCI3) in ppm: 4.87 (d, J=2 Hz, 1H, CHCl); 3.70 (X moiety of ABX, additionally resolved with J=2 Hz, 1H, CH): 2.73-3.29 (AB moiety of ABX, 2H, CH2); 1.45-2.23 (m, 8H).

4.83 g (16.6 mmols) of 1 - chloro - 3 - (2',2',2' trichloroethyl)spiro[3.4]octan - 2 - one are added to a solution of 2.0 g of NaOH in 40 ml of water and 3 ml of dioxane and the mixture is stirred for 2 hours at room temperature and then for 3 hours at 100 C. The reaction solution is washed with diethyl ether and acidified with dilute hydrochloric acid. The acid solution is extracted with diethyl ether. The extracts are washed with water, dried over magnesium sulphate and evaporated. The residue is crystallised from n-hexane.

This gives 3.3 g of 2 - (2',2' - dichlorovinyl)spiro[2.4]heptane - I - carboxylic acid of the formula

in the form of a white powder; melting point 90105 C.

IR spectrum (CHCl3) in cm-1: 1705 (CO), 1620 (C=C).

NMR spectrum (100 MHz, CDC13/D2O) in ppm: 6.15 (d, J=9 Hz, 0.8H, CH=CCI3 cis); 5.51 (d, J=9 Hz, 0.2H, CH=CCI2 trans); 2.00-2.40 (m, 2H): 1.60- 1.95 (m, 8H).

Example 9 33.6 g (0.62 mol) of methylenecyclopropane and 152 g (0.62 mol) of 2,4,4,4 tetrachlorobutyric acid chloride in 620 ml of n-pentane are initially introduced into a 2.5 litre autoclave. 62.8 g (0.62 mol) of triethylamine in 120 ml of n-pentane are pumped in in the course of 6 hours, at 60"C, and the reaction mixture is then kept at 60"C for 6 hours. The reaction mixture is filtered, the filtrate is evaporated and the residue is distilled in vacuo. The fraction having a boiling range of 45 80"C/0.09 mm Hg is then chromatographed on 250 g of silica gel using hexan4(w 50 O by weight toluene. The pure fractions are evaporated and the residue is distilled. This gives I - chloro - I - (2',2',2' - trichloroethyl)spiro[3.2]hexan - 2 one of the formula

having a boiling point of 70--71"C/0.08 mm Hg.

IR spectrum (CHCl3) in cm-1: 1776 (CO).

1H NMR spectrum (100 MHz, CDCI3) in ppm: 0.8-1.8 (m, 4H); 2.6-3.8 (m, 4H).

A solution of 11.0 g (42 mmols) of I - chloro - I - (2',2',2' trichloroethyl)spiro[3.2]hexan - 2 - one and 1.17 g (6.3 mmols) of tributylamine in 15 ml of toluene is refluxed for 5 hours. After cooling, the reaction mixture is diluted with n-pentane. The mixture is washed with 2 N sulphuric acid and then with saturated sodium chloride solution, dried over sodium sulphate and evaporated. The residue is distilled in vacuo. This gives I - chloro - 3 - (2',2',2' trichloroethyl)spiro[3.2]hexan - 2 - one of the formula

having a boiling point of 600C/0.01 mm Hg.

IR spectrum (CCl4) in cm-': 1780 (CO).

NMR spectrum (100 MHz, CDCI3) in ppm: 0.8-1.7 (m, 4H); 2.6H.2 (m, 3H); 4.75, 5.15 (one d in each case; together 1H).

7.1 g (27 mmols) of I - chloro - 3 - (2',2',2' - trichloroethyl)spiro[3.2ihexan 2 - one, together with 54 ml (about 135 mmols) of 10% strength NaOH, are refluxed for 2 hours. After cooling, the mixture is washed with several portions of diethyl ether, acidified with sulphuric acid and extracted with diethyl ether. The ether extracts are evaporated after drying over sodium sulphate. A small amount of strongly polar impurities is removed by filtering on silica gel (eluant: diethyl ether).

After concentrating the filtrate, 2 - (2',2' - dichlorovinyl)spiro[2.2]pentane - I carboxylic acid of the formula

is obtained as an approximately 3:1 cis/trans mixture; melting point 77--78"C.

IR spectrum (CCl4) in cm-1: 1675 (CO).

NMR spectrum (100MHz, CDCI3) in ppm: 0.8-2.85 (m, 6H); 5.56 and 6.11 (one d in each case, together lH); 10.8 (broad s, 1H).

The examples which follow describe the preparation of some insecticidal active compounds.

Example 10 Preparation of the m-phenoxybenzyl Ester of 2 - (2',2' - dichlorovinyl) - 3,3 dimethylcyclopropane - I - carboxylic Acid a) 4.18 g (0.02 mol) of 2 - (2',2' - dichlorovinyl) - 3,3 dimethylcyclopropane - I - carboxylic acid and 20 ml of thionyl chloride are warmed at 700C for 3 hours. The excess thionyl chloride is then evaporated off, the residue is taken up in 100 ml of benzene and the mixture is evaporated again. A solution of 4.0 g (0.02 mol) of m-phenoxybenzyl alcohol in 40 ml of absolute benzene is added to this residue 12 - (2',2' - dichlorovinyl) - 3,3 dimethylcyclopropanecarboxylic acid chlorides and the mixture is warmed to 400C. 2.2 g (0.022 mol) of triethylamine in 10 ml of absolute benzene are added dropwise to this mixture in the course of one hour and the reaction mixture is stirred for a further I hour at this temperature. The reaction mixture is washed with dilute hydrochloric acid, dried over magnesium sulphate and evaporated. The residue is chromatographed on silica gel using diethyl ether/n-hexane as the eluant (1:4 mixture by volume). This gives the m-phenoxybenzyl ester of 2 - (2',2' dichlorovinyl)- 3,3 - dimethylcyclopropane - 1 - carboxylic acid having a refraction of nD =1.5628.

b) 5.28 g (0.02 mol) of 2 - (2',2',2' - trichloroethyl) - 3,3 - dimethyl - 4 chlorocyclobutan - 1 - one, dissolved in 25 ml of absolute dimethoxyethane, are added dropwise to a solution of 4.0 g (0.02 mol) of m-phenoxybenzyl alcohol. 0.5 g (0.021 mol) of NaH and 40 ml of absolute dimethoxyethane. The reaction mixture is then stirred for 1 hour at 450C, 2.25 g (0.02 mol) of potassium tert.-butylate are then added and the mixture is refluxed for 3 hours. After it has been discharged into water, it is acidified with dilute hydrochloric acid and extracted with benzene. The evaporated extract is chromatographed on silica gel using diethyl ether/n-hexane as the eluant (1:4 mixture by volume). This gives the m-phenoxybenzyl ester of 2 (2',2' - dichlorovinyl) - 3,3 - dimethylcyclopropane - 1 - carboxylic acid in the form of a viscous oil, which has the same properties as the substance obtained according to a).

Example 11 - Cyano - m - phenoxybenzyl cis - 2 - (2',2' - dichlorovinyl)- 3,3 dimethylcyclopropanecarboxylate 10 g (0.047 mol) of cis - 2- (2',2' - dichlorovinyl) - 3,3 dimethylcyclopropanecarboxylic acid in 100 ml of benzene are stirred with 12.1 ml (0.141 mol) of oxalyl chloride for 24 hours at room temperature. After evaporating the reaction solution, the brown residue is distilled under reduced pressure. This gives 9.1 g of a clear liquid; boiling point 50"C/0.04 mm Hg. 3.0 g of this clear liquid are dissolved in 30 ml of toluene and 2 ml of pyridine are added. 2.9 g of a cyano - m - phenoxybenzyl alcohol in 20 ml of toluene are added dropwise to this mixture at room temperature and the reaction mixture is then stirred for a further 16 hours at room temperature. The reaction mixture is washed, first with water, then with saturated sodium bicarbonate solution and subsequently with salt water, dried over magnesium sulphate and evaporated. the residue is chromatographed on silica gel (elution with diethyl ether/n-hexane, 1:2). This gives pure a - cyano - m phenoxybenzyl cis - 2 - (2',2' - dichlorovinyl) - 3,3 dimethylcyclopropanecarboxylate as a mixture of diastereomers.

NMR spectrum (60 MHz, CDC13) in ppm: 1.201.43 (m, 6H, CH3): 1.67-2.35 (m, 2H, 2xCH); 6.25 (d, J=9 Hz, 1H, CH-CCl2); 6.40 and 6.45 (Is in each case, 0.5H in each case, CH-CN); 6.98-7.65 (m, 9H).

Example 12 7.8 g (0.1 mol) of absolute pyridine are added dropwise, at room temperature, to a solution of 22.75 g (0.1 mol) of crude 2.- (2',2' - dichlorovinyl) - 3,3 dimethylcyclopropanecarboxylic acid chloride [prepared according to Example la)] and 21.5 g (0.1 mol) of 3 - phenoxy - a - hydroxyethylbenzene in 250 ml of absolute toluene. The reaction mixture is stirred for 15 hours at room temperature (2--25"C), washed with dilute hydrochloric acid and then with water, dried (over sodium sulphate) and evaporated. The residue is chromatographed on silica gel using n-hexane/diethyl ether as the eluant (1:1 mixture by volume). This gives a methyl - m - phenoxybenzyl 2 - (2',2' - dichlorovinyl) - 3,3 dimethylcyclopropanecarboxylate in the form of a colourless oil of nD =1.563.

WHAT WE CLAIM IS: 1. A process for the preparation of a 2 - (2',2',2' - trihalogenoethyl) - 4 halogenocyclobutan - 1 - one of the formula I

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (23)

1. **WARNING** start of CLMS field may overlap end of DESC **.

   Example 10 Preparation of the m-phenoxybenzyl Ester of 2 - (2',2' - dichlorovinyl) - 3,3 dimethylcyclopropane - I - carboxylic Acid a) 4.18 g (0.02 mol) of 2 - (2',2' - dichlorovinyl) - 3,3 dimethylcyclopropane - I - carboxylic acid and 20 ml of thionyl chloride are warmed at 700C for 3 hours. The excess thionyl chloride is then evaporated off, the residue is taken up in 100 ml of benzene and the mixture is evaporated again. A solution of 4.0 g (0.02 mol) of m-phenoxybenzyl alcohol in 40 ml of absolute benzene is added to this residue 12 - (2',2' - dichlorovinyl) - 3,3 dimethylcyclopropanecarboxylic acid chlorides and the mixture is warmed to 400C. 2.2 g (0.022 mol) of triethylamine in 10 ml of absolute benzene are added dropwise to this mixture in the course of one hour and the reaction mixture is stirred for a further I hour at this temperature. The reaction mixture is washed with dilute hydrochloric acid, dried over magnesium sulphate and evaporated. The residue is chromatographed on silica gel using diethyl ether/n-hexane as the eluant (1:4 mixture by volume). This gives the m-phenoxybenzyl ester of 2 - (2',2' dichlorovinyl)- 3,3 - dimethylcyclopropane - 1 - carboxylic acid having a refraction of nD =1.5628.

   b) 5.28 g (0.02 mol) of 2 - (2',2',2' - trichloroethyl) - 3,3 - dimethyl - 4 chlorocyclobutan - 1 - one, dissolved in 25 ml of absolute dimethoxyethane, are added dropwise to a solution of 4.0 g (0.02 mol) of m-phenoxybenzyl alcohol. 0.5 g (0.021 mol) of NaH and 40 ml of absolute dimethoxyethane. The reaction mixture is then stirred for 1 hour at 450C, 2.25 g (0.02 mol) of potassium tert.-butylate are then added and the mixture is refluxed for 3 hours. After it has been discharged into water, it is acidified with dilute hydrochloric acid and extracted with benzene. The evaporated extract is chromatographed on silica gel using diethyl ether/n-hexane as the eluant (1:4 mixture by volume). This gives the m-phenoxybenzyl ester of 2 (2',2' - dichlorovinyl) - 3,3 - dimethylcyclopropane - 1 - carboxylic acid in the form of a viscous oil, which has the same properties as the substance obtained according to a).

   Example 11 - Cyano - m - phenoxybenzyl cis - 2 - (2',2' - dichlorovinyl)- 3,3 dimethylcyclopropanecarboxylate

   10 g (0.047 mol) of cis - 2- (2',2' - dichlorovinyl) - 3,3 dimethylcyclopropanecarboxylic acid in 100 ml of benzene are stirred with 12.1 ml (0.141 mol) of oxalyl chloride for 24 hours at room temperature. After evaporating the reaction solution, the brown residue is distilled under reduced pressure. This gives 9.1 g of a clear liquid; boiling point 50"C/0.04 mm Hg. 3.0 g of this clear liquid are dissolved in 30 ml of toluene and 2 ml of pyridine are added. 2.9 g of a cyano - m - phenoxybenzyl alcohol in 20 ml of toluene are added dropwise to this mixture at room temperature and the reaction mixture is then stirred for a further 16 hours at room temperature. The reaction mixture is washed, first with water, then with saturated sodium bicarbonate solution and subsequently with salt water, dried over magnesium sulphate and evaporated. the residue is chromatographed on silica gel (elution with diethyl ether/n-hexane, 1:2). This gives pure a - cyano - m phenoxybenzyl cis - 2 - (2',2' - dichlorovinyl) - 3,3 dimethylcyclopropanecarboxylate as a mixture of diastereomers.

   NMR spectrum (60 MHz, CDC13) in ppm: 1.201.43 (m, 6H, CH3): 1.67-2.35 (m, 2H, 2xCH); 6.25 (d, J=9 Hz, 1H, CH-CCl2); 6.40 and 6.45 (Is in each case, 0.5H in each case, CH-CN); 6.98-7.65 (m, 9H).

   Example 12 7.8 g (0.1 mol) of absolute pyridine are added dropwise, at room temperature, to a solution of 22.75 g (0.1 mol) of crude 2.- (2',2' - dichlorovinyl) - 3,3 dimethylcyclopropanecarboxylic acid chloride [prepared according to Example la)] and 21.5 g (0.1 mol) of 3 - phenoxy - a - hydroxyethylbenzene in 250 ml of absolute toluene. The reaction mixture is stirred for 15 hours at room temperature (2--25"C), washed with dilute hydrochloric acid and then with water, dried (over sodium sulphate) and evaporated. The residue is chromatographed on silica gel using n-hexane/diethyl ether as the eluant (1:1 mixture by volume). This gives a methyl - m - phenoxybenzyl 2 - (2',2' - dichlorovinyl) - 3,3 dimethylcyclopropanecarboxylate in the form of a colourless oil of nD =1.563.

   WHAT WE CLAIM IS: 1. A process for the preparation of a 2 - (2',2',2' - trihalogenoethyl) - 4 halogenocyclobutan - 1 - one of the formula I

   in which one of the radicals R, and R2 is methyl and the other is hydrogen or methyl, or R, and R2 together are an alkylene group having 2 to 4 carbon atoms, and X and Y are each chlorine or bromine, but if X is bromine Y must always be bromine, which comprises reacting a 2,4,4,4 - tetrahalogenobutyric acid chloride of the formula II

   in which X and Y are as defined under formula~I, in the presence of an organic base with an olefine of the formula III

   in which R, and R2 are as defined under formula I, to give a 2 - (2',2',2' trihalogenoethyl) - 2 - halogenocyclobutan - I - one of the formula IV

   in which R1, R2, X and Y are as defined under formula I, and then rearranging the latter, in the presence of a catalyst, into a 2 - (2',2',2' - trihalogenoethyl) - 4 halogenocyclobutan - I - one of the formula I.
2. 2. A process according to Claim 1, which comprises using 2,4,4,4 - tetrachlorobutyric acid chloride as the 2,4,4,4 - tetrahalogenobutyric acid chloride of the formula II.
3. 3. A process according to Claim 1, which comprises using an olefine of the formula III in which one of the radicals R, and R2 is methyl and the other is hydrogen or methyl, or R1 and R2 together are an alkylene group having 2 to 3 carbon atoms.
4. 4. A process according to Claim 1, which comprises using isobutylene as the olefine of the formula III.
5. 5. A process according to Claim I, which comprises using methylenecyclopropane as the olefine of the formula III.
6. 6. A process according to Claim 1, which comprises carrying out the reaction of a 2,4,4,4 - tetrahalogenobutyric acid chloride of the formula II with an olefine of the formula III in the presence of pyridine or of a trialkylamine having 1 to 4 carbon atoms in each alkyl group and in the presence of an inert organic solvent.
7. 7. A process according to Claim 1, which comprises carrying out the reaction of a 2,4,4,4 - tetrahalogenobutyric acid chloride of the formula II with an olefine of the formula III in the presence of triethylamine.
8. 8. A process according to Claim 1, which comprises using an inorganic or organic proton acid as the catalyst for the rearrangement of a 2 - (2',2',2' trihalogenoethyl) - 2 - halogenocyclobutan - I - one of the formula IV into a 2 (2',2',2' - trihalogenoethyl) - 4 - halogenocyclobutan - I - one of the formula I.
9. 9. A process according to Claim 1, which comprises using a hydrogen halide acid as the catalyst for the rearrangement of a 2 - (''.2','' - trihalogenoethvl) - 2 halogenocyclobutan - I - one of the formula IV into a 2 - (2','',7' trihalogenoethyl) - 4 - halogenocyclobutan - I - one of the formula I.
10. 10. A process according to Claim 1, which comprises using an organic base as the catalyst for the rearrangement of a 2 - (2',2',2' - trihalogenoethyl) - 2 halogenocyclobutan - I - one of the formula IV into a 2- (2'.2',2' - trihalogenoethyl) - 4 - halogenocyclobutan - I - one of the formula I.
11. Il. A process according to Claim 1, which comprises using an amine of the formula

    in which Q1 is alkyl having I to 8 carbon atoms, cycloalkyl having 5 to 6 carbon atoms, benzyl or phenyl and Q2 and Q3 independently of one another are hydrogen or alkyl having I to 8 carbon atoms, as the catalyst for the rearrangement of a 2 (2',2',2' - trihalogenoethyl) - 2 - halogenocyclobutan - I - one of the formula IV into a 2 - (2',2',2' - trihalogenoethyl) - 4 - halogenocyclobutan - 1 - one of the formula I.
12. 12. A process according to Claim 1, which comprises using a salt of a proton acid with ammonia, a nitrogen-containing organic base or a quaternary ammonium salt as the catalyst for the rearrangement of a 2 - (2',2',2' - trihalogenoethyl) - 2 halogenocyclobutan - I - one of the formula IV into a 2- (2',2',2' - trihalogenoethyl) - 4 - halogenocyclobutan - I - one of the formula I.
13. 13. A process according to Claim 1, which comprises using a salt of a hydrogen halide acid with an aliphatic, cycloaliphatic, araliphatic or aromatic primary, secondary or tertiary amine or a heterocyclic nitrogen base as the catalyst for the rearrangement of a 2 - (2',2',2' - trihalogenoethyl) - 2 - halogenocyclobutan - 1 one of the formula IV into a 2- (2',2',2'- trihalogenoethyl)- 4halogenocyclobutan - 1 - one of the formula I.
14. 14. A process according to Claim 1, which comprises using a salt of the formula

    in which M is fluorine, bromine or iodine and especially chlorine, Q4 is hydrogen, alkyl having 1 to 18 carbon atoms, cyclohexyl, benzyl, phenyl or naphthyl and Q5, Q8 and Q7 independently of one another are hydrogen or alkyl having I to 18 carbon atoms, or a N-alkylpyridinium halide having I to 18 carbon atoms in the alkyl group, as the catalyst for the rearrangement of a 2 - (2',2',2' trihalogenoethyl) - 2 - halogenocyclobutan - I - one of the formula IV into a 2 (2',2',2' - trihalogenoethyl) - 4 - halogenocyclobutan - 1 - one of the formula I.
15. 15. A process according to Claim 1, which comprises carrying out the rearrangement of a 2 - (2',2',2' - trihalogenoethyl) - 2 - halogenocyclobutan - 1 one of the formula IV into a 2- (2',2',2' - trihalogenoethyl)- 4halogenocyclobutan - I - one of the formula I at temperatures of between 80 and 1300C.
16. 16. A process according to Claim 1, which comprises carrying out the rearrangement of a 2 - (2',2',2' - trihalogenoethyl) - 2 - halogenocyclobutan - I one of the formula IV into a 2- (2',2',2' - trihalogenoethyl)- 4halogenocyclobutan - 1 - one of the formula I in the melt at a temperature of between 80 and 1300C in the presence of a trialkylamine having 1 to 8 carbon atoms in each alkyl group or of a tetraalkylammonium halide having 1 to 18 carbon atoms in the alkyl groups.
17. 17. A process according to Claim 1, which comprises carrying out the rearrangement of a 2 - (2',2',2' - trihalogenoethyl) - 2 - halogenocyclobutan - I one of the formula IV into a 2- (2',2',2' - trihalogenoethyl)- 4halogenocyclobutan - I - one of the formula I in the presence of an inert solvent.
18. 18. A process according to Claim I, which comprises carrying out the rearrangement of a 2 - (2',2',2' - trihalogenoethyl) - 2 - halogenocyclobutan - I one of the formula IV into a 2 - (2',2',2' - trihalogenoethyl)- 4halogenocyclobutan - I - one of the formula I in an aliphatic alcohol having I to 4 carbon atoms, toluene, xylene, chlorobenzene, dioxane, acetonitrile, 3methoxypropionitrile, ethylene glycol, diethyl ether or diisopropyl ketone, as the solvent.
19. 19. A 2 - (2',2',2' - trihalogenoethyl) - 2 - halogenocyclobutan - I - one of the formula IV

    in which one of the radicals R1 and R2 is methyl and the other is hydrogen or methyl, or R, and R2 together are alkylene having 2 to 4 carbon atoms, and X and Y are each chlorine or bromine, but if X is bromine, Y must always also be bromine.
20. 20. A 2 - (2',2',2' - trihalogenoethyl) - 4 - halogenocyclobutan - 1 - one of the formula I

    in which one of the radicals R1 and R2 is methyl and the other is hydrogen or methyl, or R, and R2 together are alkylene having 2 to 4 carbon atoms, and X and Y are each chlorine or bromine, but if X is bromine Y must always also be bromine.
21. 21. The use of a 2 - (2',2',2' - trihalogenoethyl) - 4 - halogenocyclobutan I - one of the formula I

    in which one of the radicals R, and R2 is methyl and the other is hydrogen or methyl, or R1 and R2 together are alkylene having 2 to 4 carbon atoms, and X and Y are each chlorine or bromine, but if X is bromine Y must always also be bromine, in the preparation of a compound of the formula VIII

    .in which one of the radicals R, and R2 is methyl and the other is hydrogen or methyl, or R, and R2 together are alkylene having 2 to 4 carbon atoms, X is chlorine or bromine and R is hydrogen, alkyl having 1 to 4 carbon atoms or a group of the formula IX

    in which R3 is oxygen, sulphur or a vinylene group, R4 is hydrogen, alkyl having I to 4 carbon atoms, benzyl, phenoxy or phenylmercapto, R5 is hydrogen or an alkyl group having 1 to 4 carbon atoms and R6 is hydrogen, cyano or ethynyl, or, if one of the radicals R1 and R2 is methyl and the other is hydrogen or methyl, R3 is a vinylene group, R4 is phenoxy and R5 is hydrogen, also alkyl having I to 5 carbon atoms.
22. 22. Any one of the compounds of formula I as defined in Claim 20 hereinbefore particularly described.
23. 23. A compound of the formula VIII as defined in Claim 21 when prepared by use of a compound of formula I, as claimed in Claim 21.