Certain thiazolotriazolyphosphonothioates used as insecticides

Abstract

A compound represented by the formula ##SPC1##WhereinR.sub.1 and R.sub.2 are lower alkyl having six or less carbon atoms,X is bromine is used to combat phylophogous insects.

Description

This invention relates to novel thiazolotriazolylphosphonothioates and to a process for the preparation of the same. Further, the invention relates to insecticidal and acaricidal compositions containing one or more of said novel compounds and further includes methods for combatting insects and mites with these compounds.

A number of organo phosphate insecticides have been used for the control of many injurious insects and certain materials are known to be effective. However, many of these systemic insecticides have a strongtoxicity for human and warm-blooded animals.

Among harmful insects are, phytophagous mites which give great damage to plants and crops. Indeed a crop free from mite damage can scarcely be found. The damage is very large and considerable money for extermination expense is spent annually. Further, some insects and mites having resistance against the currently employed insecticides and acaricides have recently appeared. Therefore, it becomes a matter of importance to control the insects and the mites. Accordingly, development of novel, effective insecticides and acaricides is desired in order to control these insects and mites.

The inventors have discovered that the compounds of this invention have superior insecticidal and acaricidal activities.

The novel compounds of this invention are characterized by the following formula: ##SPC2##

Wherein

R.sub.1 and R.sub.2 are lower alkyl having six or less carbon atoms,

X is bromine.

It is one object of the present invention to provide new thiazolotriazolylphosphonothioates, which are useful in the control of insects and mites. It is another object of the present invention that the compounds of the invention have sufficient low phyto-toxicity so that they can be used to without any injury to living plants and to provide agents having extremely low mammal toxicity.

In the Japanese Patent Publication No. 30192/1971 it has been shown that 0,0-dialkyl-2-thiazolo[3,2-b]-s-triazolylthionophosphates having no substituent at 6 position therein are useful as insecticidal and acaricidal compositions.

But the inventors herein synthesized various thiazolotriazolylphosphonothioates and tested the biological activity thereof, and have discovered that thiazolotriazolylphosphonothioates having at the 6 position a bromine substituent have strong insecticidal and acaricidal activities and furthermore, these compounds have very low mammal toxicity.

For example, acute oral toxicity LD.sub.50 (mouse) of 0,0-diethyl-2-(5-methylthiazolo[3,2-b]-s-triazolyl)thionophosphates of Japanese Patent Publication No. 30192/1971 is 33-50 mg/kg, but one of 0,0-diethyl-2-(5-methyl-6-bromothiazolo[3,2-b]-s-triazolyl)thionophosphate of the present invention is 150 mg/kg, so that it can be said to be comparatively safe.

The compounds of this invention can be prepared in accordance with the following equation: ##SPC3##

(wherein R.sub.1, R.sub.2 and X represent the herein after described meanings.)

Usually the process of the invention is carried out in a proper inert solvent by the use of alkali condensing agents. As an inert solvent, acetone, dioxane, acetonitrile and pyridine have been employed. Using these inert solvents, the compounds of this invention are obtained in low yields such as 5 to 6%.

However, the inventors have discovered that the compounds of this invention are be obtained in satisfactory high yields such as 50 to 70% when dimethylformamide or dimethylsufoxide are employed as solvents in the presence of potassium carbonate or sodium carbonate as condensing agents.

In a practical method, the compounds of this invention are prepared through the reaction of 0,0-dialkylthiophosphorylchloride with 6-halogenothiazolo[3,2-b]-s-triazol using dimethylformamide or dimethylsulfoxide as a solvent in the presence of alkali carbonate as a condensing agent, or with alkali metal salts of 6-halogenothiazolo[3,2-b]-s-triazol which are dissolved in the solvent such as dimethylformamide or dimethylsulfoxide.

Reaction temperature is 40.degree. - 60.degree.C, preferably 45.degree. - 50.degree.C and the reaction terminates after 4 and 10 hours.

After the reaction is terminated, the products are isolated from the reaction mixture by employing the following treatment.

The reaction mixture is poured into water after cooling to room temperature, this water mixture is alkalized by adding dilute sodium hydroxide solution and unreacted starting materials are dissolved in the alkali solution. The crystallized material was collected by filtration, washed with water and dried, and the crude product is obtained as a crystal.

The crude product can be purified by recrystallizing from a mixture of ligroin and petroleum ether.

The desired product is obtained as white crystal.

Unreacted starting material can be recovered from the mother liquor and acidified with hydrochloric acid solution.

In order to facilitate a clear understanding or the invention, the following preferred specific embodiments are described as illustrative examples and not as limiting the invention.

EXAMPLE 1.

0,0-Dimethyl-2-(5-methyl-6-bromothiazolo[3,2-b]-s-triazolyl)thionophosphate

4.68 g of 2-hydroxy-5-methyl-6-bromothiazolo[3,2-b]-s-triazole, 3 g of potassium carbonate and 3 g of 0,0-dimethylthiophosphoryl chloride were dissolved in 100 ml of dimethylformamide and heated at 45.degree. - 50.degree.C for 4 hours under agitation. Then the reaction mixture was poured into water and alkalized sodium hydroxide solution to crystallize the reaction product. The crystallized material was gathered by filtration, washed with water and dried. The dried crystal was recrystallized from mixed solvent of ligroin and petroleum ether and 4.1 g of white crystal having a melting point of 100.degree. - 102.degree.C were obtained. The crystal consist of 0,0-dimethyl-2-(5-methyl-6-bromothiazolo[3,2-b]-s-triazolyl)thionophosphate, and the elemental analysis was as follows: Found (%); C, 23.41; H, 2.55; N, 11.95; S, 17.64; Calcd. for C.sub.7 H.sub.9 BrN.sub.3 O.sub.3 PS.sub.2 (%); C, 23.47; H, 2.53; N, 11.73; S, 17.90.

EXAMPLE 2.

0,0-Diethyl-2-(5-methyl-6-bromothiozolo[3,2-b]-s-triazoly)thionophosphate

4.86 g of 2-hydroxy-5-methyl-6-bromothiazolo[3,2-b]-s-triazole, 3 g of potassium carbonate and 3.4 g of 0,0-diethylthiophosphoryl chloride were dissolved in 100 ml of dimethylformamide and heated at 45.degree. - 50.degree.C for 4 hours under agitation.

By a procedure similar to Example 1, 5 g of 0,0-diethyl-2-(5-methyl-6-bromothiazolo[3,2-b]-s-triazolyl)thionophosphate having a melting point of 102.degree. - 103.degree.C were obtained. Elemental analysis was as follows: Found (%); C, 27.83; H, 3.47; N, 11.11; S, 16.22; Calcd. for C.sub.9 H.sub.13 BrN.sub.3 O.sub.3 PS.sub. 2 (%); C, 27.99; H, 3.39; N, 10.88; S, 16.60.

EXAMPLE 3.

0,0-Dimethyl-2-(5-methyl-6-chlorothiazolo[3,2-b]-s-triazolyl)thionophosphate

3.79 g of 2-hydroxy-5-methyl-6-chlorothiazolo[3,2-b]-s-triazole, 3 g of potassium carbonate and 3 g of 0,0-dimethylthiophosphoryl chloride were dissolved in 100 ml of dimethylformamide and heated at 45.degree. - 50.degree.C for 4 hours under agitation.

By a procedure similar to Example 1, 3.4 g of 0,0-dimethyl-2-(5-methyl-6-chlorothiazolo[3,2-b]-s-triazolyl)thionophosphate having a melting point of 73.degree. - 75.degree.C were obtained. Elemental analysis was as follows: Found (%) ; C, 26.71 ; H, 2.94 ; N, 13.67 ; S, 20.34 ; Calcd. for C.sub.7 H.sub.9 ClN.sub.3 O.sub.3 PS.sub.2 (%) ; C, 26.80 ; H, 2.89; N, 13.39 ; S, 20.44.

EXAMPLE 4.

0,0-Diethyl-2-(5-methyl-6-chlorothiazolo[3,2-b]-s-triazolyl)thionophosphate

3.79 g of 2-hydroxy-5-methyl-6-chlorothiazolo[3,2-b]-s-triazole, 3 g of potassium carbonate and 0,0-diethylthiophosphoryl chloride were dissolved in 100 ml of dimethylformamide and 3.4 g heated at 45.degree. - 50.degree.C for 4 hours under agitation.

By a procedure similar to Example 1, 4.5 g of 0,0-diethyl-2-(5-methyl-6-chlorothiazolo[3,2-b]-s-triazolyl)thionophosphate having a melting point of 80.degree. - 82.degree.C were obtained. Elemental analysis was as follows: Found (%) ; C, 31.54 ; H, 3.78 ; N, 12.76 ; S, 18.54 ; Calcd. for C.sub.9 H.sub.13 ClN.sub.3 PS.sub.2 (%) ; C, 31,63 ; H, 3.83 ; N, 12.30 ; S, 18.76.

In addition to the above mentioned compound described in the preceding examples, some typical compounds of the present invention are listed in Table I.

Table I______________________________________ ##STR1##Compound No. R.sub.1 R.sub.2 X m.p. (.degree.C)______________________________________I CH.sub.3 CH.sub.3 Br 100 - 102II C.sub.2 H.sub.5 C.sub.2 H.sub.5 Br 102 - 103III CH.sub.3 CH.sub.3 Cl 73 - 75IV C.sub.2 H.sub.5 C.sub.2 H.sub.5 Cl 80 - 82V CH.sub.3 C.sub.2 H.sub.5 Br 93 - 95______________________________________

Hereinafter, the compounds of this invention are represented by Compound No. in Table 1.

The method of the present invention comprehends the employment of a liquid or solid composition containing one or more of the present compounds as an active component.

The compound can be used directly without mixing with suitable carriers.

The active ingredient of this invention may be formulated by mixing with suitable carriers in a form generally used in pesticidal composition such as wettable powder, emulsifiable concentrate, dust formulation, granular formulation, water soluble powder and aerosol. As solid carriers, bentonite, diatomaceous earth, apatite, gypsum, talc, pyrophyllite, vermiculite, clay and others are used. As liquid carriers, kerosene, mineral oil, petroleum, solvent naphtha, xylene, cyclohexane, cyclohexanone, dimethylformamide, dimethylsulfoxide, alcohol, acetone, benzene and others are used. Sometimes surface active agent is added in order to give a homogeneous and stable formulation.

Furthermore, the composition may be applied as a mixture with other fungicides, insecticides, acaricides, plant growth regulators and fertilizers.

The concentrations of the active ingredients in the insecticidal and acaricidal compositions of this invention vary according to type of formulation, and they are, for example, used in a range of 5 - 80 weight percent, preferably 20 - 80 weight percent, in wettable powders, 5 - 70 weight percent, preferably 10 - 50 weight percent, in emulsifiable concentrates, and 0.5 - 20 weight percent, preferably 1 - 10 weight percent in dust formulations.

The non-limiting examples for the insecticidal and acaricidal compositions are illustrated as follows:

EXAMPLE 5.

Wettable Powder

Parts by weightCompound I 40Higher alcohol sulfonate ester 5Diatomaceous earth 51White carbon 4

These are mixed homogeneously and micronized to fine particles. Consequently, wettable powder containing 40 % of active ingredient is obtained. In practical use, it is diluted to a certain concentration with water and is sprayed as a suspension.

EXAMPLE 6.

Emulsifiable Concentrate

Parts by weightCompound II 30xylene 40dimethylformamide 22polyoxyethylene alkylarylether 8

These are mixed and dissolved.

Consequently, emulsifiable concentrate containing 30% of the active ingredient is obtained. In practical use, it is diluted to certain concentration with water and then is sprayed as an emulsion.

EXAMPLE 7

Dust Formulation

Parts by weightCompound III 3Talc 97

These are mixed homogeneously and micronized to fine particles. Consequently, dust formulation containing 3% of the active ingredient is obtained. In practical use it is directly applied.

In the Example 5 - 7, it is not intended to limit the emulsifying, wetting or dispersing agents, carriers and solvents to the ones described by way of illustration.

The compounds listed in Table 1 possess very superior insecticidal and acaricidal activities compared to known compounds.

The superior insecticidal and acaricidal effects of the novel compounds of this invention are clearly illustrated by the following tests.

In these all tests, 0,0-dimethyl-2-(5-methylthiazolo[3.2-b]-s-triazolyl)thionophosphate of the Japanese Patent Publication No. 30192/1971 is compared with the compounds of this invention.

TEST 1.

Insecticidal Activity Against Fly

Fixed concentration of acetone solution containing test compound were prepared.

20 house flies (Musca domestica Linne) were tested with 1 .mu. l of acetone solution at their thoracic dosial by microsyringe and kept at a temperature of 25.degree.C and at a humidity of 65%. 24 hours and 48 hours after treatment, dead flies were counted and mortality (%) was calculated. The results were shown in Table 2.

Table 2______________________________________Test *Contrast Active compound 1/1 fly active compound 0.5/1 flyCompound 24 hrs. 48 hrs. 24 hrs. 8 hrs.______________________________________I 100 100 95 100II 100 100 90 100III 100 100 90 95IV 100 100 90 100V 100 100 90 100Contrast* 100 100 70 70______________________________________ *Contrast : 0,O-dimethyl-2-(5-methylthiazolo[3,2-b]-s-triazolyl)thionophosphate

TEST 2.

Insecticidal Activity Against Cockroach

Acetone solution of test compound were dropped on filter paper having a diameter of 9cm in order that active compound on filter paper became 125 and 31.3mg/m.sup.2. The filter paper was airdried and setted in schale, and in which 10 hatched nymph (American cockroach, Periplaneta americana Linne) were inoculated.

24 hours and 72 hours after inoculation, dead insects were counted and mortality (%) was calculated.

The results were shown in Table 3.

Table 3______________________________________ Active compound Active compoundTest 125 mg/m.sup.2 31.3 mg/m.sup.2Compound 24 hrs. 72 hrs. 24 hrs. 72 hrs.______________________________________I 100 100 30 100II 100 100 100 100III 100 100 40 100IV 100 100 100 100V 100 100 100 100Contrast* 100 100 0 30______________________________________

TEST 3.

Insecticidal Activity Against Mosquito

An aqueous suspension of wettable powder formulated in similar manner to Example 5 were poured in 200 ml beaker and in which 20 Japanese celler mosquito (Culex pipiens pallens Coqvii Maskell) were inoculated. 24 hours and 48 hours after inoculation, dead mosquitos were counted and mortality (%) were calculated.

The results were shown in Table 4.

Table 4______________________________________Conc. of Active Test Com-Ingredient pound No. II Contrast*(ppm) 24 hrs. 48 hrs. 24 hrs. 48 hrs.______________________________________0.0833 100 1000.0417 10 1000.0209 0 300.0105 0 00.00830.0067 100 1000.0042 100 1000.0021 95 1000.0011 15 90______________________________________

TEST 4.

Insecticidal Activity Against Aphid

A potted chrysanthemum which Chrysanthemum aphid (Macrosiphoniella sanborni Gillette) infestation and a potted apple which Woolly apple aphid (Eriosoma lanigerum Hausmann) infestation were used.

An aqueous suspension of wettable powder formulated in similar manner to Example 5 were sprayed. After a fixed number of days from spraying, the state of the Aphid was observed and estimated according to following grading.

- : no effect

+ : weak effect

++ : considerable effect

+++ : nearly perfect effect

The results were shown in Table 5.

Table 5______________________________________ Chrysanthemum aphid Woolly apple aphid (Conc. of Active (Conc. of ActiveTest Ingredient 100 ppm) Ingredient 500 ppm)Compound 7 days 10 days 7 days 10 days______________________________________I +++ +++ +++ +++II +++ +++ +++ +++III +++ +++ +++ +++IV +++ +++ +++ +++V +++ +++ +++ +++Contrast* +++ +++ ++ +++______________________________________

TEST 5

Insecticidal Activity Against Cabbage Armyworm

10 Multigeneration breeded armyworms (Leucania separata Walker) were used for this test.

A leaf of corn plant was dipped in an aqueous emulsion of emulsifiable concentrate formulated in similar manner to Example 6 for 30 seconds and air dried. Then the leaf was placed on filter paper having 9 cm diameter on a scale. The test insects were inoculated into the scale and the scale was put on the cover. After 1 day and 3 days from inoculation, dead insects were counted and mortality (%) were calculated. The results were shown in Table 6.

Table 6__________________________________________________________________________ Concentra- Concentra- Concentra- Concentra- tion tion tion tionTest 62.5 ppm 31.3 ppm 15.7 ppm 7.8 ppmCompound 1 day 3 days 1 day 3 days 1 day 3 days 1 day 3 days__________________________________________________________________________I 100 100 100 100 90 100 60 100II 100 100 100 100 100 100 80 90III 100 100 100 100 80 100 50 90IV 100 100 90 100 80 100 50 90V 100 100 100 100 90 100 70 100Contrast* 90 100 70 100 30 80 0 0__________________________________________________________________________

TEST 6.

Test for Control of Mite

About 30 adult female mites of desert spider mite (Tetranychus desertorum Banks) laid on main leaves of the potted kidney bean plants grown 7 and 10 days stage after sprouting. One day later, the wounded mites were removed from the plants. The compounds to be tested were sprayed on the plants as water suspension of emulsifiable concentrate prepared by the method of Example 6. After 1 day and 3 days from spraying, dead mites was counted and mortality (%) was calculated.

Rating of mortality was recorded as follows:

Mortality Rating______________________________________100 % +++99 - 90 % ++89 - 50 % +50 - 0 % -______________________________________

The results are shown in Table 7.

Table 7______________________________________ Concentration of Active IngredientTest 125 ppm 31.3 ppm 7.81 ppmCompound 1 day 3 days 1 day 3 days 1 day 3 days______________________________________1 +++ +++ +++II +++ +++ +++III +++ +++ +++IV +++ +++ +++V +++ +++ +++Contrast* +++ +++ ++ +++______________________________________

Claims

1. A method of preventing injury to plants by phytophagous insects comprising applying to the plants to be protected an insecticidally effective amount of a compound represented by the formula: ##SPC4##

in which R.sub.1 and R.sub.2 are each methyl or ethyl.

2. The method of claim 1 in which a composition is applied to said plants containing said compound and a carrier.

3. The method of claim 2 in which said carrier is selected from the group consisting of solid carriers and liquid carriers, said solid carriers being selected from the group consisting of bentonite, diatomaceous earth, apatite, gypsum, talc, pyrophyllite, vermiculite, and clay, said liquid carriers being selected from the group consisting of kerosene, mineral oil, petroleum, solvent naphtha, xylene, cyclohexane, cyclohexanone, dimethylformamide, dimethylsufoxide, alcohol, acetone, and benzene.

4. The method of claim 3 in which said composition is in the form of a wettable powder and the concentration of active ingredient in said wettable powder is from 5 to 80 weight percent.

5. The method claim 3 in which said composition is in the form of an emulsifiable concentrate and the concentration of active ingredient in said emulsifiable concentrate is from 5 to 70 weight percent.

6. The method of claim 3 in which said composition is in the form of a dust formulation and the concentration of active ingredient in said dust formulation is from 0.5 to 20 weight percent.