The present invention relates to benzoyl urea deri­vatives having insecticide activity and more precisely it re­lates to 1-benzoyl-3-aryl-urea derivatives, particularly ac­tive against eggs and larvae of insects which are noxious in agrarian and civil field and to the use of said derivatives.

Moreover the invention relates to the synthesis pro­cess of these ureas. Several 1-benzoyl-3-aryl-urea derivati­ves are known, endowed with insecticide activity.

Among these compounds, the first product put on the commerce was Diflubenzuron, usual name of compound 1-(2,6-­difluorobenzoyl)-3-(4-chloro-phenyl)-urea described in U.S. patent 3.933.908 (U.S. Philips Corporation).

Difluorobenzuron, however, as it contains in its mo­lecule the unit of 4-chloro-aniline, is suspected of being a carcinogen [European Chem. News 6 (16), 29 (1978)].

We have now found, and they form an object of the present invention, derivatives of 1-benzoyl-3-aryl-urea ha­ving general formula:

wherein:

R represents a chlorine or fluorine atom;

R₁ represents a hydrogen, chlorine or fluorine atom;

R₂ and R₅, which may be the same or different, represent a hydrogen, halogen atom, an alkyl group containing from 1 to 4 carbon atoms, a haloalkyl group containing from 1 to 4 carbon atoms;

R₃ and R₄, which may be the same or different, represent a hydrogen, halogen atom, an alkyl, haloalkyl, alkoxy or halo alkoxy group;

Z represents an oxygen or sulphur atom;

R₆ and R₉, which may be the same or different, represent a hydrogen, halogen atom, an alkyl, haloalkyl, alkoxy, haloal­koxy group;

R₇ and R₈, which may be the same or different, represent a hydrogen, halogen atom, an alkyl, haloalkyl, alkoxy, halo­alkoxy group;

X represents an oxygen or sulphur atom;

Y represents an alkylene group containing from 2 to 4 carbon atoms, a haloethylene or haloethenyl group or haloethenylene group;

R₁₀ represents a C₁-C₄ alkyl, C₁-C₄ haloalkyl, C₃-C₄ alkenyl, C₃-C₄ haloalkenyl, C₃-C₄ cycloalkyl, C₃-C₄ halocycloalkyl or C₃-C₄ cycloalkenyl group.

In aforesaid definitions, with the term halogen (fluorine, chlorine, bromine and iodine) preferably a fluorine, chlorine or bromine atom is meant, moreover, if it is not indicated otherwise, the alkylic parts of R₃, R₄, R₆, R₇, R₈ and R₉ have to be meant C₁-C₄ (including C₁, C₂, C₃ and C₄ alkylic parts).

The compounds having formula (I) are endowed with insecticide activity and may be used in agrarian, forestal, civil and veterinarian field for fighting insect infestations.

In the description of the preparation of the compounds having formula (I), as set forth hereinafter, symbols R, R₁, R₂, R₃, R₄, R₅, R₆, R₇, R₈, R₉, R₁₀, X, Y, Z have the meanings set forth in formula (I), if it is not specified otherwise.

The compounds having formula (I) are obtained by let­ting react a benzoyl-isocyanate having formula:

with an aromatic amine having formula:

The reaction does not require the presence of cata­lysts and is carried out in an inert solvent and at tempera­tures ranging from 0°C to the boiling temperature of the mix­ture.

Aromatic hydrocarbons, chlorinated hydrocarbons, ethers, ketones and acetonitrile are suitable solvents.

The benzoylisocyanates having formula (II) are known compounds and at times they can be found on the market.

The amines having formula (III) can be prepared, according to known methods, for instance: by letting react the sodium or potassium salt of a suitable aminophenoxy phenol (V), in di­polar aprotic solvents or mixtures of such solvents with aro­matic hydrocarbons, with ethereal compound:

    CF₂= CF-OR₁₀      (IV)

wherein R₁₀ has the meaning given in formula (I), at tempera­tures ranging from 10 to 40°C, according to the following equation:

The ethers having formula (IV) can be prepared accor­ding to known methods, described for instance in J. Am. Chem. Soc., 82, 5116 (1960) when R₁₀ is an alkyl or aryl group and in J. Org. Chem., 48, 242 (1983) when R₁₀ is a polyhaloalkyl group.

As it is evident to a person skilled in the art, se­veral alternative procedures are possible for the synthesis of the intermediates and of the products having formula (I).

An alternative procedure for the synthesis of com­pounds having formula (I) consists, for instance, in letting react a benzamide having formula:

with a isocyanate having formula:

Such reaction is carried out under conditions similar to the ones above described for the reaction between the ben­zoyl isocyanate having formula (II) and the amine having for­mula (III).

The preparation of the isocyanates having formula (VII) foresees , however, the preparation of the amines ha­ving formula (III) and the reaction of said amines with phos­gene.

This point of view, together with the fact that the benzoyl-isocyanates having formula (II) are available as the amides of formula (VI) are, leads generally to prefer the synthesis method reported hereinbefore, namely the reaction between the compounds having formula (II) and (III).

As above mentioned, the compounds having formula (I) are endowed with high insecticide activity, showing mostly against larvae and eggs of insects.

Among these insects, the ones belonging to the Lepi­doptera, Diptera and Coleoptera orders can be fought parti­cularly by means of the compounds having formula (I).

These orders comprise several species that are impor­tant owing to their noxiousness in agrarian, forestal, civil and veterinarian field. Therefore the compounds having for­mula (I) are fit for different uses, for instance, for protec­ting agricultural cultivations, from infestations of phytopha­gous insects, for protecting environments infested by mosqui­toes and flies, for protecting breeding-cattle from a few cattle parasites and so on.

Moreover the compounds having formula (I) show a col­lateral acaricide activity.

For the practical uses the compounds having general formula (I) may be used as such or, more suitably, in the form of compositions containing, in addition to one or more of the compounds of formula (I) as active principle, solid or liquid inert vehicles and optionally other additives as well. According to the customary formulative praxis, the compositions can be in the form of wettable powders, emulsi­fiable concentrates, dispersable powders, aqueous solutions or dispersions and the like.

The amount of active principle in the compositions ranges within wide limits (1-95% by weight), depending on the type of composition and on the use such a composition is al­lotted to.

If required by particular situations or in order to extend the action spectrum, other active substances such as, for instance, other insecticides or acaricides, can added to the compositions. The amount of active substance (compound of formula I) to be distributed for the insecticide treatments depends on different factors such as, for instance, the kind of infestation and its degree, the environment wherein the infestation breaks out (agrarian cultivations, basins and water-courses, organic substrates of different nature, and the like),the kind of composition that has been used, climatic and environmental factors, available application means and so on. In general, amounts of active substance ranging from 0.01 to 1 kg/ha are sufficient for a good disinfestation. The follo­wing examples will now better illustrate the invention.

In the proton nuclear magnetic resonance spectra(¹H-­NMR), set forth in examples, use is made of the following abbreviations:

s = singlet;

m = multiplet or unresolved complex signal;

t = triplet;

b = (broad) = broadened signal.

EXAMPLE 1

Preparation of N-2,6-difluorobenzoyl-N′-3-chloro-4-­[4-(1,1,2,-trifluoro-2-(trifluoromethoxy)ethoxy)phenoxy] phe­nylurea (compound No 1).

1.0 g of 3-chloro-4-[-4-(1,1,2,-trifluoro-2-(trifluoro­methoxy)ethoxy)phenoxy] aniline (prepared as described in sub­sequent example 3) dissolved in 15 ml of anhydrous ethyl ether, was introduced, in a nitrogen atmosphere, into a 50 ml flask equipped with a cooler, dropping funnel, thermometer and ma­gnetic stirrer. Then 0.46 g of 2,6-difluorobenzoylisocyanate dissolved in 4.5 ml of anhydrous chlorobenzene, were dripped there at room temperature. The mixture was heated at 50°C over 60 min­utes, cooled and filtered. The filtrate was concentrated at re­duced pressure and the product was separated by filtration.

One obtained 0.77 g of benzoylurea having a melting point of 133-135°C.

EXAMPLE 2

By starting from the anilines described in subsequent example 3 and by operating under conditions similar to the ones described in example 1, the following compounds were ob­tained, by using 2,6-difluorobenzoylisocyanate:

- Compound No 2

N-2,6-difluorobenzoyl-N′-4-[4-(1,1,2,-trifluoro-2-(trifluo­ro-methoxy)ethoxy)phenoxy]phenylurea:

m.p. 153-158°C.

- Compound No 3

N-2,6-difluorobenzoyl-N′-2-fluoro-4-[4-(1,1,2-trifluoro-2-­(trifluoromethoxy)ethoxy)phenoxy]phenylurea.

m.p. 118-120°C.

- Compound. No 4

N-2,6-difluorobenzoyl-N′-4-[3-chloro-4-(1,1,2,-trifluoro-2-­(trifluoromethoxy)ethoxy)phenoxy]phenylurea:

m.p. 139-141°C.

- Compound No 5

N-2,6-difluorobenzoyl-N′-4-[2-chloro-4-(1,1,2-(trifluoro)­-2-(trifluoromethoxy)-ethoxy)phenoxy]phenylurea:

m.p. 120-122°C.

While using 2-chlorobenzoyl isocyanate the follo­wing compounds were prepared:

- Compound No 6

N-2-chlorobenzoyl-N′-3-chloro-4-[4-(1,1,2,-trifluoro-2-(tri­fluoromethoxy)ethoxy)phenoxy]phenylurea:

m.p. 130-132°C.

- Compound No 7:

N-2-chlorobenzoyl-N′-4-[4-(1,1,2,-trifluoro-2-(trifluorome­thoxy)ethoxy)phenoxy]phenylurea:

m.p. 150-153°C.

- Compound No 8:

N-2-chlorobenzoyl-N′-2-fluoro-4-[4-(1,1,2,-trifluoro-2-(tri­fluoromethoxy)ethoxy)phenoxy]phenylurea:

m.p. 103-104°C.

- Compound No 9:

N-2-chlorobenzoyl-N′-4-[3-chloro-4-(1,1,2,-trifluoro-2-(tri­fluoromethoxy)ethoxy)phenoxy]phenylurea:

m.p. 119-122°C.

- Compound No 10:

N-2-chlorobenzoyl-N′-4-[2-chloro-4-(1,1,2,-trifluoro-2-(tri­fluoromethoxy)ethoxy)phenoxy]phenylurea:

m.p. 108-110°C.

EXAMPLE 3

Preparation of intermediate anilines.

6.93 g of 3-chloro-4-(4-hydroxy-phenoxy)aniline, 6.1 ml of dimethyl sulfoxide, 24.4 ml of toluene and 1.65 g of ground potassium hydroxide were loaded into a two neck flask equipped with a thermometer, magnetic stirrer and gas feeding device.

One produced the vacuum in the flask, and one linked said flask with a reservoir containing 4.6 g of perfluorome­thylperfluorovinylether.

The reaction mixture was stirred over 60 minutes at room temperature. One poured into water, one extracted with ethyl ether, one dehydrated and one concentrated under vacuum.

The obtained raw product was purified by chromatogra­phy on silica gel column.

One obtained 6.53 g of 3-chloro-4-[4-(1,1,2-trifluoro­-2-(trifluoromethoxy)ethoxy)phenoxy]aniline.

¹H-NMR (CDCl₃): 7.1-6.15 (m, 7.5 H); 5.3 (t, 0.5 H); 3.5 (bs,2H).

By operating under conditions similar to the ones described hereinbefore, 4-[4-(1,1,2,-trifluoro-2-(trifluorome­thoxy)ethoxy)phenoxy]aniline was obtained, starting from 4-(4-hydroxy-phenoxy)aniline.

¹H-NMR (CDCl₃): 7.15-6.15 (m, 8.5 H); 5.35 (t, 0.5 H); 4.0 (bs, 2H).

2-fluoro-4-[4-(1,1,2-trifluoro-2-trifluoromethoxy) ethoxy)-phenoxy]aniline was obtained starting from 2-fluoro­-4-(4-hydroxy-phenoxy)aniline.

¹H-NMR (CDCl₃): 7.1-6.1 (m, 7.5 H); 5.35 (t, 0.5 H); 3.5 (bs, 2H).

4-[3-chloro-4-(1,1,2,-trifluoro-2-(trifluoromethoxy) ethoxy)phenoxy]aniline was obtained, starting from 4-(3-chlo­ro-4-hydroxy-phenoxy)aniline.

¹H-NMR (CDCl₃): 7.3-6.2 (m, 7.5 H); 5.4 (t, 0.5 H); 3.5 (bs, 2H).

4-[2-chloro-4-(1,1,2,-trifluoro-2-(trifluoromethoxy) etoxy)phenoxy]aniline was obtained starting from 4-(2-chloro­-4-hydroxy-phenoxy)aniline.

¹H-NMR (CDCl₃): 7.2-6.2 (m, 7.5 H); 5.4 (t, 0.5 H); 3.5 (bs, 2H).

EXAMPLE 4

Determination of the insecticide activity.

Test 1

Immediate residual activity on larvae of Spodoptera littoralis (Lepidoptera).

Tobacco leaves were sprayed mechanically with a wa­ter-acetone solution (10% by volume of acetone) containing a surfactant and the product being tested.

After complete removal of the solvents, the leaves were infested with second age larvae of Lepidoptera.

The infested leaves were kept in a suitably conditio­ned place during the time required for the test.

Tobacco leaves, treated only with a water-acetone so­lution (10% of acetone) containing the surfactant, to be used as comparison (comparison test), were infested and kept like­wise.

Ten days after the infestation and after having rene­wed at least once the treated substrate, the reckoning was car­ried out of the dead larvae in comparison with the comparison test.

Test 2

Activity on larvae of Aedes aegypti (Diptera).

Tap water (297 ml) was mixed with an acetone solution (3 ml) containing the product being tested in a suitable concen­tration.

25 larvae of Diptera, being 4 days of age and fed sui­tably, were introduced into the obtained solution. Other lar­vaes were introduced, as comparison test, into a water-aceto­ne solution (acetone 3 ml, tap water 297 ml), containing no active product.

Every 2-3 days a note was made of dead larvae and pu­pae and of adult insects emerged from the cocoon normally, till the emergence from the cocoon of the insects, in the compari­son test, was over.

The activity of the product being tested was expressed as per cent ratio of dead individuals compared with the total number of treated individuals.

The insecticide activity in aforesaid tests was expressed according to the following scale of valves:

5 = complete activity      (98-100% of mortality)

4 = high activity      (80-97% of mortality)

3 = fairly good activity      (60-79% of mortality)

2 = sufficient activity      (40-59% of mortality)

1 = scanty activity      (20-39% of mortality)

0 = negligible or no activity      (0-19% of mortality)

The data of insecticide activity at the indicated doses, expressed according to the above reported scale of values, are set forth in following Table 1.