2,2-Dichlorocyclopropylmethyl-phosphoric acid derivatives of the formula I ##STR1## where R.sup.1, R.sup.2 and R.sup.3 are identical or different and are hydrogen or methyl, PA1 R.sup.4 is unbranched or branched alkoxy of up to 4 carbon atoms, unbranched or branched alkylthio of up to 4 carbon atoms, amino, or alkylamino or dialkylamino, where each alkyl is of up to 5 carbon atoms and is linear or branched, PA1 Y is oxygen or sulfur and PA1 X.sup.1, X.sup.2, X.sup.3 and X.sup.4 are identical or different and each is hydrogen, halogen, nitro, cyano, methyl or methylthio, and their use for controlling pests from the classes of insects, Arachnidae and Nemathelminthes.

The present invention relates to 2,2-dichlorocyclopropyl-methyl-phosphoric 
acid derivatives, pesticides which contain these phosphoric acid 
derivatives as active ingredients, and a process for combating pests. 
German Laid-Open Application DOS No. 2,634,587 discloses 
S-2,2-dihalo-cyclopropyl-methyl-phosphoric acid derivatives which may be 
used for controlling insects and nematodes. 
We have found that 2,2-dichlorocyclopropylmethyl-phosphoric acid 
derivatives of the formula I 
##STR2## 
where R.sup.1, R.sup.2 and R.sup.3 are identical or different and are 
hydrogen or methyl, 
R.sup.4 is unbranched or branched alkoxy of up to 4 carbon atoms, 
unbranched or branched alkylthio of up to 4 carbon atoms, amino, or 
alkylamino or dialkylamino, where each alkyl is of up to 5 carbon atoms 
and is linear or branched, 
Y is oxygen or sulfur and 
X.sub.1, X.sub.2, X.sub.3 and X.sub.4 are identical or different and each 
is hydrogen, halogen, nitro, cyano, methyl or methylthio, 
possess a very good insecticidal, acaricidal and nematicidal activity and 
are superior to known active ingredients of similar structure and of the 
same type of action. 
Examples of linear or branched alkoxy radicals R.sup.4 are methoxy, ethoxy, 
propoxy, isopropoxy and butoxy; examples of alkylthio substituents R.sup.4 
are methylthio, ethylthio, propylthio, isopropylthio, n-butylthio and 
isobutylthio; examples of alkylamino and dialkylamino radicals are 
methylamino, dimethylamino, ethylamino, diethylamino, methylethylamino, 
isopropylamino, di-n-propylamino, n-butylamino and di-n-butylamino. 
Preferred compounds of the formula I are those where R.sup.1, R.sup.2 and 
R.sup.3 are hydrogen, R.sup.4 is methoxy, ethoxy, methylthio, propylthio, 
isobutylthio, amino, methylamino, dimethylamino or isopropylamino, 
especially methoxy, Y is oxygen or sulfur and X.sup.1, X.sup.2, X.sup.3 
and X.sup.4 are hydrogen, nitro or methylthio. 
The 2,2-dichlorocyclopropyl-methyl-phosphoric acid derivatives of the 
formula I may be obtained by reacting a phenol of the formula II, in the 
presence or absence of an acid acceptor, or by reacting an alkali metal 
salt, alkaline earth metal salt or unsubstituted or substituted ammonium 
salt of such a phenol, with a (thio)phosphoric acid diester halide or 
ester-amide halide of the formula III, in accordance with the following 
equation: 
##STR3## 
In this equation, R.sup.1, R.sup.2, R.sup.3, R.sup.4, X.sup.1, X.sup.2, 
X.sup.3, X.sup.4 and Y have the above meanings and Hal is halogen, 
preferably chlorine. 
The reaction is advantageously carried out in a solvent or diluent which is 
inert to the reactants. Examples of suitable solvents and diluents are 
aliphatic and aromatic hydrocarbons and chlorohydrocarbons, eg. petroleum 
ether, benzene, toluene, xylene, gasoline, methylene chloride, chloroform, 
carbon tetrachloride and chlorobenzene, ethers, eg. diethyl ether, 
di-n-butyl ether, methyl tert.-butyl ether, tetrahydrofuran and dioxane, 
ketones, eg. acetone, methyl ethyl ketone and methyl isopropyl ketone, and 
nitriles, eg. acetonitrile and propionitrile. Mixtures of these solvents 
or diluents may also be used. 
All conventional acid-binding agents may be used as acid acceptors in the 
reaction of the phenol of the formula II; alkali metal carbonates and 
alcoholates, eg. sodium carbonate, potassium carbonate, sodium methylate 
and ethylate and potassium methylate and ethylate, prove to be 
particularly suitable, as do aliphatic, aromatic and heterocyclic amines, 
eg. triethylamine, N,N-dimethylethylamine, trimethylamine, 
N,N-dimethylaniline, dimethylbenzylamine and pyridine. 
Instead of carrying out the reaction in the presence of an acid acceptor, 
it is equally possible first to prepare a salt of the phenol, for example 
an alkali metal salt, alkaline earth metal salt, ammonium salt or 
substituted ammonium salt, preferably an alkali metal salt or ammonium 
salt, in an undiluted form, and then to react this salt further. 
To carry out the process, the starting materials are mostly employed in the 
equimolar ratio. An excess of one or other reactant can offer advantages 
in certain cases. 
The reaction temperature can be varied within a substantial range. In 
general, the reaction is carried out at from 0.degree. to 120.degree. C., 
preferably from 25.degree. to 60.degree. C. 
The reaction is in general carried out under atmospheric pressure. 
The (thio)phosphoric acid diester halides and ester-amide halides of the 
formula III, used as starting materials for the preparation of the 
compounds I, can be prepared from the 2,2-dichlorocyclopropylcarbinols of 
the formula IV, known from the literature (Acta Chim. Scand., Ser. B, 31 
(1977), 463 et seq.) via the 
2,2-dichlorocyclopropyl-methyl-(thio)phosphoric acid ester dihalides or 
amide dihalides of the formula VI, in accordance with the following 
equations, where the radicals R.sup.1, R.sup.2, R.sup.3, R.sup.4, Y and 
Hal have the above meanings: 
##STR4## 
In some cases it can be advantageous to modify the above reaction sequence 
so that the reaction takes place in accordance with the following 
equations: 
##STR5## 
The (thio)phosphoric acid ester dihalides and amide dihalides VI and VII 
formed as intermediates in the above reaction sequences can either be 
isolated in an undiluted form or be directly converted to the compounds of 
the formula III by using a one-vessel process. 
To prepare the compounds of the formula III, the reactants shown in the 
above equations are preferably employed in the equimolar ratio. 
For the first reaction stage of each alternative, ie. the reaction of a 
compound of the formula V with a compound of the formula IV or with a 
compound of the formula R.sup.4 H, the reaction temperature may be from 
-70.degree. C. to 0.degree. C., preferably from -40.degree. C. to 
-25.degree. C. The second stage is, in both alternatives, carried out at 
from -50.degree. to +30.degree. C., preferably from -20.degree. to 
0.degree. C. 
Both stages of the reaction may, if desired, be carried out in the presence 
of an organic solvent which is inert to the reactants, for example in an 
aliphatic or aromatic hydrocarbon or chlorohydrocarbon, eg. pentane, 
hexane, petroleum ether, toluene, xylene, gasoline, methylene chloride, 
chloroform, carbon tetrachloride or chlorobenzene, an ether, eg. diethyl 
ether, methyl tert.-butyl ether, dibutyl ether or tetrahydrofuran, a 
ketone, eg. acetone, methyl ethyl ketone or methyl isopropyl ketone, or a 
nitrile, eg. acetonitrile or propionitrile. 
Suitable acid acceptors are the acid-binding agents mentioned above in the 
context of the preparation of the compounds of the formula I. Tertiary 
aliphatic amines, eg. triethylamine, trimethylamine, 
N,N-dimethyl-N-ethylamine and heterocyclic amines, eg. pyridine, have 
proved particularly advantageous. 
The compounds of the formula III can also be readily prepared without 
addition of an acid acceptor if the compound R.sup.4 H, in the form of an 
alkali metal salt, is reacted direct with a compound of the formula V or 
VI.