CS207649B2 - Insecticide means and method of making the active substances - Google Patents

Abstract

Insecticidal benzamides of formula: <IMAGE> wherein R represents <IMAGE> X represents oxygen or sulfur; one of R<1> or R<2> represents hydrogen and the other represents fluoro, chloro, bromo, trifluoromethyl or methoxy; one of R<3> and R<4> represents hydrogen and the other represents methoxy or trifluoromethyl; one of R<5> and R<6> represents hydrogen and the other represents chloro, bromo, fluoro, trifluoromethyl or hydrogen; one of R<7> and R<8> represents hydrogen and the other represents C1-C2 alkoxy substituted with one or more fluorine atoms.

Description

This invention relates to insecticidal compositions comprising as an efficacious ingredient ^one novel N- (l, 3,4-thiadiazol-2-yl) benzamide, comprising in the 5-position of the thiadiazole ring is phenyl, naphthyl or heteroaryl residue whose phenyl residue is substituted benzoic acid in positions 2 and 6, as well as a process for the preparation of these active substances.

Insect control was one of the first problems facing agrochemical research, and this problem is being intensively pursued. Insect pests of numerous orders and species attack utility plants of all types, cause hygiene problems and contaminate food and feed. The damage caused by insects is incalculable and the control of harmful insects is a matter of paramount importance.

More recently, research into new and better insecticides has been prompted by the withdrawal of old insecticides that leave residues.

The compounds of formula (I) below are. in organic chemistry by new substances, some of the prior art works. however, they are 'interesting'. So. Cebalo, for example, in U.S. Pat. 3,726,892 discloses herbicidally active 1,3,4-thiadiazol-2-ylureas.

Rao in Indian J. Chem. 8, 509-513 (1970) describes a method for synthesizing 2-amino-1,3,4-thiadiazoles which are. intermediates for preparing compounds of the invention.

Weling and Mueller in U.S. Patent 3,748,356 disclose the heribicidal and insecticidal activity of N-benzoyl-N‘-phenylureas.

The invention is in the field of agrochemistry and describes a process for the preparation of the novel thiadiazolylbenzamides of the general formula I,

R

^Oc W ^j in which

R is a radical of formula

II)

207849

where

X represents oxygen or sulfur, one of R ¹ and R ² is hydrogen and the other is fluorine, chlorine, bromine, trifluoromethyl or methoxy group, one of R ³ and R ⁴ is hydrogen and the other is methoxy or trifluoromethyl; one of R ⁵ and R ⁶ is hydrogen and the other is chlorine, bromine or fluorine, trifluoromethyl or hydrogen, and one of R ⁷ and R ⁸ is hydrogen and the other is C 1 -C 2 alkoxy, substituted with 1 to 5 fluorine atoms, characterized in that the 2-amino-5-R-substituted-1,3,4-thiadiazole of the general formula P is acylated,

in which

R is as defined in formula I, the benzoyl halide of formula III,

in which ; . and'·,·...'

Hal represents a chlorine or bromine atom,

The invention also relates to insecticidal compositions containing, as active ingredients, the abovementioned compounds of the general formula I as well as methods for controlling insect pests using such compositions and active ingredients.

Throughout the text, all temperatures are in degrees Celsius, all parts and percentages are parts and percentages by weight, and the term "halogen atom" refers to fluorine, chlorine, bromine and iodine atoms.

The compounds of formula (I) are prepared by methods known per se or analogous to those known per se.

All of the above compounds can be readily prepared by acylating the 2-amino-5-R-substituted-1,3,4-thiadiazoles of formula II with the benzoyl halides of formula III.

The acylation is carried out in the presence of a base in a reaction solvent such as tetrahydrofuran, dimethylformamide, dimethylsulfoxide or diethyl ether. The preferred base is sodium hydride, although other organic bases such as pyridine, triethylamine and triethanolamine, as well as inorganic bases, including sodium hydroxide, potassium carbonate and lithium bicarbonate, may also be used. Said reactions are carried out at a temperature of about -10 ° to 75 °, preferably about 0 to 25 °.

The intermediate aminothiadiazoles of formula II are prepared by well known reactions. In general, they are prepared either by oxidative cyclization of the corresponding thiosemicarbazone, preferably ferric chloride, or by dehydration cyclization of the corresponding thiosemicarbazide with a strong acid. (See, for example, Rao and Cebalo, cited above.)

All of the starting materials used in the preparation of the compounds of the invention are readily obtainable by conventional methods.

The invention is illustrated by the following non-limiting examples. In all cases, compounds were identified by NMR spectroscopy, elemental microanalysis, and in some cases by IC spectroscopy and mass spectroscopy.

Example 1

N- [5- (4-Trifluoromethoxyphenyl) -1,3,4-thiadiazol-2-yl] -2,6-dimethoxybenzamide

A mixture of 1.8 ml of pyridine and 5.2 g of 2-amino-5- (4-trifluoromethoxyphenyl) -1,3,4-thiadiazole in 50 ml of tetrahydrofuran is heated to reflux and added dropwise over 15 minutes. 4.4 g of 2,6-dimethoxybenzoyl chloride in 20 ml of tetrahydrofuran. The resulting mixture is refluxed for 45 minutes, the solvent is evaporated off under vacuum and the residue is recrystallized from aqueous ethanol to give 7.2 g of the above product. white needle-like crystals, m.p. 201-203 °.

Example 2

N- [5- (6-methoxy-2-benzo [b] furyl) -1,3,4-thiadiazol-2-yl) -2,6-dimethoxybenzamide

To 100 ml of tetrahydrofuran containing 0.7 g of 2-amino-5- (6-methoxy-2-benzo [b] furyl] -1,3,4-thiadiazole is added 0.3 g of sodium hydride. 0.62 g of 2,6-dimethoxybenzoyl chloride was stirred at room temperature for 1 hour, the solvent was evaporated in vacuo, water was added and the mixture was acidified with 1N hydrochloric acid. Recrystallization from benzene / hexane gave 0.12 g of the above product, melting at 215-217 °.

Using the general procedure described in Examples 1 and 2, the compounds of Examples 3 to 8 were also prepared. In each of these examples, the title product of each product clearly shows the substituents of the starting aminothiadiazole and benzoyl halide. The names of the resulting compounds are listed first, and then in the form of an overview of the amounts of starting materials and end products, as well as the melting points of the products.

Example 3

Example 4

N- [5- (5-Methyl-2-benzo [b] furyl) -1,3,4-thiadiazol-2-yl] -2,6-dimethoxybenzamide

Example 5

N- [5- (5-trifluoromethyl-2-benzo [b] furyl} -1,3,4-thiadiazol-2-yl] -2,6-dimethoxybenzamide

Example

N- [5- (6-Trifluoromethyl-2-benzo [b] furyl) -1,3,4-thiadiazol-2-yl] -2,6-dimethoxybenzamide

Example 7

N- [5- (4-pent-fluoroethoxyphenyl) -1,3,4-thiadiazol-2-yl] -2,6-dimethoxybenzamide

Example 8

N- [5- (5-fluoro-2-benzo [b] furyl] -1,3,4-thiadiazol-2-yl] -2,6-dimethoxybenzamide

N- [5- (2-indenyl) -1,3,4-thiadiazol-2-yl] -2,6-dimethoxybenzamide

example number aminothiadiazole benzoyl chloride product melting point (° C) 3 1.0 1.0 0.2 230—323 4 2,0 1,8 1.3 255—257 5 2.8 2.2 2.5 242—245 6 2,0 1.6 1.0 206—208 7 3.1 2.2 1.7 227—229 8 2.4 2.2 1.7 244—245

In order to determine the insecticidal activity, the compounds of the formula I were subjected to treatment. a series of tests against live insects. Typical tests are described below and the results of these tests are presented.

In many cases, tests with a specific application rate are repeated and the average is calculated from the results obtained with these tests. Blank spaces in the tabulated data indicate that the test was not performed at the indicated application rate. Active substances' are indicated by the preparation number numbers.

Test 1 ·

Efficacy test against Epilachna varivestis and Spodoptera eridania

Each of the test compounds is made into an active agent by dissolving 10 ml of the test compound in 1 ml of a solvent consisting of equal parts of anhydrous ethanol and acetone containing 23 g of Toximul R and 13 g of Toximul S (1 liter). Toximul-R and Toximul-S are surfactants consisting of a mixture of sulfonate and non-ionic surfactants, and the solution is mixed with 9 ml of water, so that the resulting composition. contains the active substance tested at a concentration of 1000 ppm. The dispersion obtained is then diluted with water to the desired lower concentration if necessary.

The resulting dispersion is then sprayed evenly over the bean plants - aged 10 days and the treated plants are allowed to dry. The leaves are then taken from the plants and their cut ends are covered with cotton soaked water. Each of the 2 leaves was placed in a 100 mm diameter petri dish, and five Epilachna varivestis larvae (2nd or 3rd instar) and five Spodo ptera eridania larvae (2nd or 3rd) were added to each bowl. instar). The experiment was repeated three times for each of the test compounds. The plates are kept at a temperature of about 25 ° C and relative humidity for 4 days. 51%, after which a first evaluation of isecticidal efficacy is performed. Some of the dishes are kept in the air-conditioned chamber for a further 3 days, after which further evaluation is performed.

Isecticidal activity is expressed on a scale of 0 to 3, compared to control experiments in which plants are treated with solvent only and not treated at all. Individual values of the above scale. have the following meanings:

= no effect, = 1 to 7 larvae killed, = 8 to 14 larvae killed, = 15 larvae killed.

Results. The efficacy assays of typical compounds of the invention are summarized. to the following table:

the compound of Example Number Table 1 Spodoptera eridania applied dose in ppm Epilachna varivestis 4 days 7 days 4 days 7 days 2 1000 2 2 2 2 100 ALIGN! 1 2 1 2 3 1000 0 1 3 3 100 ALIGN! 0 0 2 3 4 1000 0 0 0 0 100 ALIGN! 0 0 0 0 5 1000 0 3 3 3 100 ALIGN! 0 2 3 3 6 1000 0 2 3 3 100 ALIGN! 0 2 2 3 7 1000 2 3 3 3 100 ALIGN! 2 3 . 3 3 8 1000 2 2 3 3 100 ALIGN! 1 1 3 3

The compound of Example 1 was further tested in the same manner, but at different application rates, where the number of insect larvae killed was not expressed on a 0 to 3 scale but as a percentage of mortality. In a 4-day test against Spodoptera eridania larvae, this compound shows. 100% mortality at 5 ppm and at. seven-day 100% mortality test at 2.5 ppm. In the test against Epilachna varivestis, the aforementioned compound shows at. a 4-day test of 100% mortality at a dose of 5 ppm and a 7-day test of 80% mortality at a dose of 2.5 ppm.

The above data demonstrates the high insecticidal activity of the compounds of formula I. It is understood that the compounds of the invention are possible. widely used to combat insects of various orders harmful to humanity for both health and economic reasons.

For example, the disclosed compounds kill the following harmful insects:

order of beetles (Soleoptera), such as

Anthonomus grandis,

Crambus caligínosellus, Oulema · melanopus,

Leptinotarsa decernlineata (Colorado potato beetle,

Hypera postica,

Anthrenus scrophulariae (Carob), Tribolium confusum ·

Lyctidae spec, Agriotesspec. (click beetles),

Sitophilus oryzae, Nodonota puncticollis a

Conotrachelus neruphar;

order Double-winged (.Diptera), such as Musea doimestica (house fly), Stomoxys calcitrans, Stemoxys irritans ·, Phormia regina '. , Hylemyia brassicae, and Psiia rosae. (carrot sting);

order of butterflies (Lpídoptera), such as Laspeyresia pomonella, (Euxoa). spec. (osenice),

They produce. interpunctella. (pepper moth)

Tartricidae spec., Heliothis zea, Ostriniia nubilalis,

Hellula rogatalis, Tri-choplusia ni

Thyridopteryx ephemeraeformis, Malacosoma americanum and Spodoptera frugiperda;

like straight-winged (Orthoptera) such as Blattella germíanica (Russian native) and Periplaneta americana (American cockroach).

The compounds of the present invention may be used to reduce insect populations by applying an insecticidally effective amount of any of the compounds to the insect-eating agent.

Insects can ingest the active ingredient by applying it to any material that eats the insect. For example, insect-infesting plants can be easily killed by applying the active ingredient to those parts of the plant which eat the insects, especially to the leaves of the plant. Insect pests infesting and feeding on textiles, paper, wood products, etc. can be easily controlled by applying the active ingredient to these materials and products. Similarly, the disclosed compounds can be effectively used to protect stored grains or seeds.

Remarkably, the disclosed compounds prevent the emergence of the following developmental stages of the insects that ingested them. For example, when the compounds of the invention ingest adult adult insects, such adults are virtually unaffected, but lay sterile eggs. If the active substance is ingested by a larva, it will die without metamorphosis at the next larval stage. The larvae in the last larval stage, which ingest the active substance, are not sacrificed but die in the umbilical form.

It will be understood that the use of a compound of Formula I does not necessarily result in the destruction of the entire insect population. In some cases, however, the entire population is killed, in other cases only a part of the insect is killed and the remaining part survives the application of the active substance. The size of the part of the population that the applied active compound kills depends on the type of insect, the active substance used, the dose applied, the viability and condition of the insects, the weather conditions and other factors known to those skilled in the art. The term 'reduction of insect populations' means, therefore, a reduction in the number of live insect specimens which, in some but not all cases, results in the disappearance of the treated insect population.

The extent of reduction of insect populations using a given compound will, of course, depend upon the dose of the compound administered. In all cases, at least an insecticidally effective amount of the compound is required. The term "insecticidally effective amount" is used to describe an amount capable of causing a measurable reduction in the treated insect population. Insecticidally effective amounts generally range from 1 to 1000 ppm.

It should be noted that the application rates of insecticides are usually expressed as the concentration of insecticide in the dispersion used for application. The application rate is measured and expressed in this way because it is most useful to apply an amount of dispersion sufficient to cover the sheets or other treated materials with a thin film of dispersion. Thus, the amount of dispersion to be applied depends on the surface area of the insect-treated material to be treated and the amount of active ingredient depends on its concentration in the applied dispersion.

The dispersions used for the application of the compounds according to the invention are prepared from the usual insecticidal compositions which, however, are novel in the present case because the new compounds according to the invention are present therein. Most commonly, aqueous dispersions prepared by mixing a small amount of concentrated insecticidal composition with an appropriate amount of water are used to achieve the desired concentration of active ingredient in the applied dispersion. Such concentrated water dispersible compositions, generally containing from 5 to 90% of the active ingredient, are usually in the form of emulsifiable concentrates, wettable powders or suspensions.

Wettable powders consist of a intimately admixed mixture of the active ingredient with an inert carrier, which is a mixture of inert powder material and surfactants. The concentration of active ingredient is usually from 10 to 90% by weight. The inert powder material is usually selected from the group of attapulgite clays, montrnorillonite clays, diatomaceous clays and purified silicates. The active surfactants which are present in the wettable powder in an amount of 0.5 to 10% by weight are usually sulfonated lignins, condensed naphthalenesulfonates, naphthalenesulfonates, alkylbenzenesulfonates, alkyl sulfates and non-homogeneous surfactants such as ethylene oxide adducts of alkylphenol.

Typical emulsifiable concentrates contain the active compound according to the invention at a suitable concentration, such as in an amount of 50-500 g per liter of liquid (corresponding to a concentration of 5-50%) dissolved in an inert carrier which is a mixture of a water-immiscible organic solvent and emulsifiers. Suitable organic solvents include aromatic hydrocarbons, in particular xylenes, and petroleum fractions, in particular higher boiling naphthalenic and olefinic petroleum fractions. However, other organic solvents such as terpenic solvents and more complex alcohols such as 2-ethoxyethanol can also be used. Emulsifiers suitable for the preparation of emulsifiable concentrates are selected from the same types and concentrations of surfactants as wettable powders.

The suspensions of the invention consist of the active ingredient in the form of a finely divided powder suspended in a suitable liquid non-solvent at a concentration similar to that of emulsifiable concentrates. The most suitable liquid non-solvent is a mixture of water and surfactants. The same types of surfactants are used for the preparation of suspensions as for the preparation of wettable powders. In many cases, small amounts of inert diluents are used to improve suspendability. Such inert diluents include swellable clays such as attapulgite and montmorillonite, starches, and in particular purified silicates.

If desired for any reason, it is equally possible to apply the active compound of the invention in the form of a solution in a suitable organic solvent, usually in petroleum oil, as in the spray oils widely used in agrochemistry.

Furthermore, the compounds of the invention may be applied in the form of dusts and aerosol formulations. Dusts consist of the active ingredient in finely powdered form dispersed in a powdered inert carrier. The carrier is usually powdered clay, such as pyrophyllite, bentonite, volcanic sediment or montmorillonite. Dusts usually contain the active ingredient in a concentration of from 0.1 to 10%.

The aerosol formulations consist of a compound of formula (I) dissolved or dispersed in an inert carrier which is a propellant propellant and is enclosed in a container from which the mixture is discharged through an atomizing valve. The propellant mixtures are either low boiling hydrocarbons or suitable suspensions pressurized with inert gases or gaseous hydrocarbons.

Claims (6)

predmbt vynalezu An insecticidal composition comprising 10 to 95% of an inert carrier and 5 to 90% of a thiadiazolylbenzamide of formula I, wherein: R is a radical of formula wherein X represents oxygen or sulfur, one of R ¹ and R ² is hydrogen and the other is fluorine, chlorine, bromine, trifluoromethyl or methoxy group, one of R ³ and R ⁴ is hydrogen and the other is methoxy or trifluoromethyl; one of R ⁵ and R ⁶ is hydrogen and the other is chlorine, bromine or fluorine, trifluoromethyl or hydrogen, and one of R ⁷ and R ⁸ is hydrogen and the other is C 1 -C 2 alkoxy, substituted with 1 to 5 fluorine atoms. 2. A composition according to claim 1, wherein the active ingredient is N- - [- (4-Trifluoromethoxyphenyl) -1,3,4-thiadiazol-2-yl] -2,6-dimethoxybenzamide. 3. A composition according to claim 1, wherein the active ingredient is N- - [5- (4-Pentafluoroethoxyphenyl) -1,3,4-thiadiazol-2-yl] -2,6-dimethoxybenzamide. 4. A process according to claim 1, wherein the 2-amino-5-R-substituted-1,3,4-thiadiazole of the formula II is acylated. N — N rAJÍ-nw ^with lili in which R is as defined in formula I, a benzoyl halide of formula III wherein: Hal represents a chlorine or bromine atom. 5. The process of clause 4, for the preparation of N- [5- (4- (trifluoromethyl) oxyphenyl-1,3,4-thiadiazol-2-yl] -2,6-dimethoxybenzamide, characterized by: The process of claim 1, wherein 2-amino-5- [4-trifluoromethoxyphenyl) -1,3,4-thiadiazole is acylated with 2,6-dimethoxybenzoyl chloride. 6. The process of clause 41, for the preparation of N- [5- (4-pentafluoroethoxyphenyl) -1,3,4-thiadiazol-2-yl] -2,6-dimethoxybenzamide, comprising: amino-5- [4-pentafluoroethoxyphenyl) -1,3,4-thiadiazole is acylated with 2,6-dimethoxybenzoyl chloride.