WO2009031822A2

WO2009031822A2 - New fluorine-containing phenyl formamidine derivatives and their use as insecticide

Info

Publication number: WO2009031822A2
Application number: PCT/KR2008/005197
Authority: WO
Inventors: Kun Hoe Chung; Young Kwan Ko; Jae Wook Ryu; Jae Chun Woo; Dong Wan Koo; Dae Whang Kim; Dong Guk Lee; No Joong Park; Yong Ho Choi; Bong Jin Chung; Tae Joon Kim; Mi Sook Hong; Chang Seop Cho
Original assignee: Korea Research Institute Of Chemical Technology; Dongbu Hitek Co., Ltd
Priority date: 2007-09-04
Filing date: 2008-09-04
Publication date: 2009-03-12
Also published as: KR20090024394A; WO2009031822A3; KR100920771B1

Abstract

The present invention relates to fluorine-containing phenylformamidine derivativ es which are represented by the Chemical formula I and useful as an insecticide for con trolling insects that are detrimental to vegetables and fruits, especially for controlling Ac arina insects, without exhibiting any toxic effect on crops and beneficial insects, an inse cticide for agricultural and horticultural use comprising the same as an effective compon ent, and a method of using the same.

Description

NEW FLUORINE-CONTAINING PHENYLFORMAMIDINE DERIVATIVES AND TH

EIR USE AS INSECTICIDE

TECHNICAL FIELD The present invention relates to fluorine-containing phenylformamidine compou nds which are represented by the following Chemical formula I and useful as an insectic ide for controlling insects detrimental to vegetables and fruits, especially for controlling Acarina insects, without exhibiting any toxic effect on crops and beneficial insects, an in secticide for agricultural and horticultural use comprising the same as an effective comp onent, and a method of using the same. [Chemical formula I]

wherein,

F represents fluorine; X represents a hydrogen atom, a cyano group, an amino group [NR²R³: R² and

R³ independently represent a hydrogen atom, a C-ι-₂ alkyl group, an acetyl group, a carb o-C-ι-₂ alkoxy group, or a C-ι-2 alkylcarbamoyl group], a carbo-Ci-₂ alkoxy group, a Ci_₂ al kylcarbamoyl group, a Ci_-4 alkyl group or alkoxy group [OR⁴: R⁴ represents a hydrogen atom, a Ci_-2 alkyl group, an acetyl group, a carbo-Ci_-2 alkoxy group, or a Ci_-2 alkylcarba moyl group];

R¹ represents a hydrogen atom, or a Ci_-4 alkyl group;

Y represents a Ci_-8 alkyl group, a dialkyl [R⁵, R⁶]aminosulfenyl group (R⁵ and R⁶ i ndependently represent a Ci-β alkyl group, a Ci_₆ haloalkyl group, or a C₅-₆ cyclic alkyl gr oup) or a N-methyl-N-arylalkylaminosulfenyl group; and, n represents 1 , 2, 3 or 4.

BACKGROUND ART

Method for the synthesis of Compound A, which has the following structure simil ar to that of the phenylformamidine compounds represented by the above-described Ch emical formula I of the present invention, is disclosed in detail in USP No. 3,284,289 (1 966), USP No. 3,496,270 (1970), USP No. 3,781 ,355 (1973), USP No. 3,929,883 (1975

), USP No. 4,128,652 (1978), and Swi 1978), etc.

In addition, phenylformamidin seful for the control of d etrimental insects, the regulation of plant growth and for killing insects, and method for producing the same are disclosed in DE 2621077(1976), USP No. 3,998,969 (1976) an d USP No. 4,356,194 (1982), as Compound B represented by the following formula.

According to the claims o the prior art documents, the phenyl group (Ph) is defi ned as "it represents a mono-, di- or tri-substituted phenyl group, and phenyl substituent s are one, two, or three halogen atoms and/or a C-M alkyl group, or an alkoxy group, a t rifluoromethyl group, a cyano group and/or a nitro group." As such, although a compo und of which phenyl group is substituted by a halogen atom has been claimed, the com pound substituted with fluorine is not specifically described. Further, in no other document known to date the fluorine-containing phenyl-for mamidine derivatives having Chemical formula I₁ which is the characteristic of the pres ent invention, has been disclosed and insecticidal activity thereof has been described.

Meanwhile, control of detrimental insects is very important for the improvement of productivity in agricultural field. Thus, various types of insecticides have been use d. However, there are lots of detrimental insects that can cause damage to agricultur al products. Conventional acaricidal agent for vegetables and fruits include those acti ng on a respiratory system, such as fenpyroximate, pyridaben, tebufenpyrad, fenazaq uin, pyrimidifen, and acequinocyl, those acting on a neurological system, such as milb ermectin, and those having a controlling effect on growth, such as etoxazole, and the Ii ke. However, it has been reported that, due to continuous use of such chemicals, det rimental insects that have developed a resistance to them also appear. For such rea sons, a development of new insecticides which have a new mechanism of controlling d etrimental insects is urgently needed. Specifically, development of environmentally fri endly and highly active insecticides which have no toxic effect on crops and beneficial i nsects but have a selective control effect against problematic insects is urgently neede d.

DETAILED DESCRIPTION OF THE INVENTION Technical Goal of the Invention

While studying to develop new insecticides for agricultural and horticultural use, inventors of the present invention prepared fluorine-containing phenylformamidine deriv atives having Chemical formula I in view of the phenylformamidine derivatives that had been reported by prior art to have an excellent insecticidal effect, and found that said flu orine-containing phenylformamidine derivatives have a better insecticidal effect compar ed to the compound disclosed in DE 2621077 and USP No. 3,998,969. The present in vention was completed accordingly.

Disclosure of the Invention As such, object of the present invention is to provide the fluorine-containing phe nylformamidine derivatives having Chemical formula I as described above and insectici des comprising the same as an effective component.

Effect of the Invention According to the present invention, it is confirmed that, among the phenyl-forma midine compounds that had been reported to have an insecticidal activity by prior art, th e fluorine-containing phenylformamidine derivatives having Chemical formula I have a r emarkable insecticidal effect compared to the chlorine- or bromine-substituted phenyl- f ormamidine compounds disclosed in the above described patent documents. In additi on, the fluorine-containing phenylformamidine compounds of the present invention hav e activity five to six times higher than that of Amitraz as a commercially available control agent, and they are expected to exhibit excellent controlling effect as a controlling age nt against detrimental insects in agricultural or horticultural field.

BEST MODE FOR CARRYING OUT THE INVENTION

In order to achieve the object of the invention as described above, the present i nvention provides novel fluorine-containing phenylformamidine derivatives as agricultur al and horticultural insecticides, that are represented by the following Chemical formula I and have an insecticidal activity with the selective control of mites and Acarina insects without exhibiting any toxic effect on crops. [Chemical formula I]

wherein,

F represents fluorine;

X represents a hydrogen atom, a cyano group, an amino group [NR²R³: R² and R³ independently represent a hydrogen atom, a Ci_-2 alkyl group, an acetyl group, a carb o-Ci-₂ alkoxy group, or a Ci_-2 alkylcarbamoyl group], a carbo-C-ι-2 alkoxy group, a Ci_-2 al kylcarbamoyl group, a Ci_-4 alkyl group or alkoxy group [OR⁴: R⁴ represents a hydrogen atom, a C₁-2 alkyl group, an acetyl group, a carbo-Ci_-2 alkoxy group, or a Ci_-2 alkylcarba moyl group];

R¹ represents a hydrogen atom, or a Ci^ alkyl group;

Y represents a Ci-β alkyl group, a dialkyl [R⁵, R⁶]aminosulfenyl group (R⁵ and R⁶ i ndependently represent a Ci_-8 alkyl group, a Ci_-6 haloalkyl group, or a C₅-₆ cyclic alkyl gr oup) or a N-methyl-N-arylalkylaminosulfenyl group; and, n represents 1 , 2, 3 or 4.

The fluorine-containing phenyl amidine derivatives of the present invention can be the compounds represented by the following Chemical formula Il when Y represents a dialkylaminosulfenyl group: [Chemical formula II]

wherein,

F represents fluorine; X represents a cyano group, an amino group [NR^ZR^J: R^ and R° independently r epresent a hydrogen atom, a Ci_-2 alkyl group, an acetyl group, a carbo-Ci-₂ alkoxy grou p, or a Ci_-2 alkylcarbamoyl group], a carbo-Ci_-2 alkoxy group, a Ci_-2 alkylcarbamoyl grou p, 2-Ci^ alkyl group or 2-alkoxy group [OR⁴: R⁴ represents a hydrogen atom, a Ci_-2 alkyl group, an acetyl group, a carbo-Ci.2 alkoxy group, or a Ci_-2 alkylcarbamoyl group]; R¹ represents a methyl group; n represents 1 , 2, or 3; and

R⁵ and R⁶ independently represent a Ci_-8 alkyl group, a C-ι-₆ haloalkyl group, an arylalkyl group, or a C_5-6 cyclic alkyl group. The fluorine-containing phenylformamidine derivatives of the present invention c an be preferably Λ/-[(di-alkylamino: R⁵, R⁶)sulfenyl]-Λ/'-(2,4,6-trifluorophenyl)-Λ/-methylfor mamidine, Λ/-[(di-alkylamino: R⁵, R⁶)sulfenyl]-Λ/'-(4-fluoro-2-methylphenyl)-Λ/-methylform amidine, Λ/-[(di-alkylamino: R⁵, R⁶)sulfenyl]-Λ/'-(4-fluoro-2-aminophenyl : NR²R³)-Λ/-meth ylformamidine or Λ/-[(di-alkylamino: R⁵, R⁶)sulfenyl]-Λ/'-(4-fluoro-2-alkoxyphenyl :OR⁴)-Λ/- methylformamidine.

The present invention also provides an agent for controlling pests, wherein the a gent comprises fluorine-containing phenyl amidine derivatives of the present invention d escribed in the above as an effective component. Said pests can be Acarina or Acari mites. Herein below, the present invention is explained in greater detail.

Specific descriptions of the compounds of the present invention having Chemica I formula I in the above are given in the following Table 1 to Table 9.

Table 2

Table 3

Table 4

Table 5

Table 6

Table 7

Table 8

Table 9

In addition, the compounds represented by the above described Chemical form ula I can be classified into three types including monoalkylphenylformamidines (A1), dia lkylphenylformlamidines (A2), and sulfenyllphenylformamidines (B) and they can be syn thesized by modification of conventional organic synthetic methods.

Various compounds represented by formula A1 can be synthesized by a reactio n between aniline derivatives and triethylorthoformate to give formimidate followed by a reaction between the resulting formimidate and various monoamines, as shown in the f ollowing Reaction scheme 1. Another synthetic method involves a reaction between a niline derivatives and Λ/-monoalkylformamide as shown in the following Reaction schem e 2.

[Reaction scheme 1]

monoalkylamine

[Reaction scheme 2]

In the preparation according to the Reaction scheme 1 described above, an imid ate is synthesized with reflux under heating in the presence of toluene as a solvent. Af ter removing excess solvent by concentration under reduced pressure, the imidate com pound was stirred with monoamine compounds at room temperature for 3 to 5 hours in the presence of tetrahydrofuran (THF) as a solvent to obtain the compounds that are re presented by the above-described formula Al In addition, in the preparation accordin g to the above-described Reaction scheme 2, aniline was reacted with excess amount o f Λ/-monoalkylformamide in the presence of one eq. of toluene sulfonylchloride by stirrin g them at room temperature for 3 hours to obtain the compounds that are represented by the above-described formula A1. The reaction mixture, after the completion of the r eaction, can be separated and purified by a general separation and purification method; for instances, it can be diluted with an organic solvent, washed with water, and the obt ained organic layer is concentrated under reduced pressure, or purified by a chromatog raphy method, if necessary.

The compounds that are represented by formula A2 above can be synthesized by reacting formimidate, which is synthesized according to the above-described Reactio n scheme 1 , with various dialkylamines. Further, instead of the Λ/-alkylformamide, Λ/-di alkylformamide can be also used with the same condition for the synthesis according to Reaction scheme 2.

The compounds that are represented by formula B were synthesized by reacting dialkylamino sulfenylchlroide and Λ/-alkylformamidine, as shown in the following Reacti on scheme 3. Dialkylamino sulfenylchlroide was synthesized according to the known methods using dialkylmines and sulfur monochloride as a starting material (Reaction scheme 4).

[Reaction scheme 3]

In the above-described Reaction scheme 3, R₂ and R₃ are the same as those d escribed before in the present text. According to the above-described Reaction schem e 3, compounds having formula B were obtained in good yield at low temperature.

Dialkylamino sulfenylchlroide was synthesized from dialkylamine, sulfur mono c hloride and sulfuryl chloride according to a reaction at low temperature condition as sho wn in Reaction scheme 4. The compounds that are represented by the above-described Chemical formula

I has an activity over a broad range of application and they can be used for controlling v arious kinds of detrimental insects which thrive on agricultural and horticultural crops. The compounds are effective not only for adult insects but also for every stage of morp hogenesis of insects including eggs, larvae, nymphs and pupae and the like. The compounds according to the present invention are effective for the control o f animal parasites and in particular plant-pathogenic Acahna, i.e., mites and Acarina incl uding Tetranychidae, Acarids, Argasidae and Dermanysidae.

Furthermore, the compounds that are represented by the above described Che mical formula I have an excellent insecticidal effect against insects which have an harm ful effect on a plant and an animal. Thus, they can be used for the control of the insec ts of the following family; Acrididae, Blattellidae, Gryllidae, Gryllotalpidae, Tettigoniidae, Cimicidae, Pyrrhocoridae, Reduviidae, Aphididae, Delphacidae, Lepidosaphes, Pseudo coccidae, Chrysomelidae, Coccinellidae, Bruchidae, Lutelidae, Dermestidae, Tenebrion idae, Curculionidae, Tineidae, Noctuidae, Lymantriidae, Pyralidae, Galleridae, Culicidae , Chironomidae, Chironomidae, Muscidae, Calliphoridae, Trypetidae and Pulicidae. A mong them, the compounds of the present invention are especially effective against mit es and aphids. Therefore, the compounds that are represented by the above-describe d Chemical formula I are particularly appropriate for the control of harmful insects in frui ts, vegetables, rice plants and horticultural plants.

The insecticide according to the present invention can be used alone or in comb ination with other herbicides or insecticides. By using together with other herbicides or insecticides, its activity can be synergistically improved. Suitable additives including o rganophosphorous compounds, nitrophenols and their derivatives, formamidines, urea, pyerthroids, carbamates and chlorinated hydrocarbons can be used.

In addition, the compounds that are represented by the above-described Chemi cal formula I can be used alone or can be used with other suitable carrier and/or additiv es. Such suitable carrier and additives can be a solid or a liquid and include a natural or recycled material, a solvent, a dispersant, a wetting agent, an adhesive, a binder and /or a fertilizer, that are used for the preparation of a common preparation.

When being used as an insecticide, the compounds having Chemical formula I can be formulated into a common formulation type, for example, powders, an emulsion, granules, a dispersion liquid, a spray composition, a solution or a suspension accordin g to a conventional method. Further, they can be prepared as cattle dip or spray race t hat are used as a transfusion formulation.

Moreover, a composition can be obtained by a conventional method which inclu des adding the active compounds having Chemical formula I and suitable carrier to a di spersant or a solvent, that is inert to the active component, followed by complete mixing and/or grinding thereof.

The insecticide according to the present invention can be used as an effective c omponent in an amount of 10 g to 500 g per 1 ha. Preferably, it is used in an amount of 10 g to 200 g per 1 ha. Dosage of the insecticide is determined based on various fa ctors including the amount of harmful insects occurred, degree of plant growth, type of a formulation and the like, and it is not limited by them.

The compounds having Chemical formula I of the present invention have an acti vity that is five to six times stronger than that of Amitraz. Further, having an excellent s afety, they can be used as a replacement for Amitraz.

Herein below, the present invention is explained in greater detail in view of the fol lowing examples. However, these examples are only to illustrate the present invention and it is not construed that the scope of the present invention is limited by the example s.

Example 1: Synthesis of /V'-(2-fluorophenyl)-Λ/-methylformamidine (1) To Λ/-methyl formamide solvent (11 ml), 2-fluoroaniline (1.11 g, 10mmol) was add ed and p-toluene sulfonylchloride (2.38g, 12.5mmol) was slowly added thereto at room t emperature followed by stirring for three hours. After confirming the completion of the reaction by TLC, the reaction mixture was poured over ice water and pH of the aqueous solution was adjusted to a basic value by adding an aqueous solution of 1ON sodium h ydroxide while maintaining the temperature of the mixture at 10^°C or less. The resultin g reaction solution was extracted three times with ethyl acetate. Thus-obtained organi c layer was washed with saturated brine, dried over anhydrous magnesium sulfate, and filtered. Further, the mixture that had been obtained by distillation of the filtrate under r educed pressure was purified by a column chromatography (development solvent: n-he xane/ethyl acetate = 1/1), yielding the yellow-colored liquid compound 1 (1.06g, 70.0%). Compound Nos. 1 to 21 of the present invention, that are described in Table 1 t o Table 3 are synthesized in the same way as the method of the above Example 1 and used.

Example 2: Synthesis of Λ/ '-(2-fluorophenyl)-Λ/, /V-dimethylformamidine (22)

In Λ/,Λ/-dimethyl formamide solvent (11ml), 2-fluoroaniline (1.11g, lOmmol) was dissolved and p-toluene sulfonylchloride (2.38g, 12.5mmol) was slowly added thereto at room temperature followed by stirring for three hours. After confirming the completio n of the reaction by TLC, the reaction mixture was poured over ice water and pH of the aqueous solution was adjusted to a basic value by adding an aqueous solution of 10N s odium hydroxide while maintaining the temperature of the mixture at 10⁰C or less. The resulting reaction solution was extracted three times with ethyl acetate. Thus-obtaine d organic layer was washed with saturated brine, dried over anhydrous magnesium sulf ate, and filtered. Further, the mixture that had been obtained by distillation of the filtrat e under reduced pressure was purified by a column chromatography (development solv ent: n-hexane/ethyl acetate = 1/1), yielding the yellow-colored liquid compound 36 (0.81 g, 49%). Compound Nos. 22 to 41 of the present invention, that are described in Table 3 and Table 4 are synthesized in the same way as the method of the above Example 2 a nd used.

Example 3: Synthesis of N-((di-n-butylamino)sulfenyl)-N'-(2-fluorophenyl)-N

-methyl formamidine (42)

Under nitrogen stream, the compound (1) (1.52g, lOmmol) was added to tetrahy drofuran (15ml) and the temperature was cooled to 0⁰C by using an ice-water bath. Th en, n-dibutylamino sulfenylchloride (2.35g, 12mmol) and triethylamine (1.52g, 15mmol) were slowly added thereto followed by stirring at room temperature for two hours. Afte r confirming the completion of the reaction by TLC, the reaction mixture was concentrat ed by evaporation under reduced pressure, and then water and dichloromethane were added thereto. Extraction was carried out three times by using dichloromethane. Th us-extracted organic layer was washed with saturated brine, dried over anhydrous mag nesium sulfate, and filtered. The filtrate was concentrated under reduced pressure an d the resulting concentrated mixture was purified by a column chromatography (develop ment solvent: n-hexane/ethyl acetate = 8/1), yielding the yellow-colored liquid compoun d 54 (2.4Og, 77%).

Compound Nos. 42 to 75 of the present invention, that are described in Table 5 to Table 9 are synthesized in the same way as the method of the above Example 3 and used_A provided that starting materials for each of the reactions were the compound No s. 1 to 21 described above.

A skilled person in the pertinent art can easily synthesize the compounds illustra ted in the above Table 1 to Table 9 by using the synthetic methods that are explained in the above examples or by modifying them.

The following examples are related to a test for measuring the control effect of t he compounds of the present invention against several harmful insects.

Example 4: Activity on brown planthopper (Nilaparvata luαens) Third instar nymph of a brown planthopper was taken as a test subject and four seedlings of Choochong rice, which had been cultivated for a week after seedling were t aken as a test plant. The prepared insecticide solution (500ppm) was applied to the s eedlings by a spray method, and the resulting seedlings were wrapped with a sterile cot ton ball and put into a test tube (3 cm diameter and 15 cm height), followed by inoculati on with ten brown planthoppers. After the treatment, the test tube was covered with a mesh cover. After 24 hours and 48 hours, respectively, the number of the alive insects was counted and the insecticidal activity was determined as percent value of dead nu mber. As a standard insecticide (LC50 : 1.6 ppm), Carbofuran was used.

As a result, it was found that Compound Nos. 10, 14, 15, 25, 34, 35 ,36, 39, 53 and 66 have an effective insecticidal activity.

Example 5: Activity on green peach aphid (Myzus persicae) An adult green peach aphid was taken as a test subject and pieces of tobacco I eaves were taken as a test plant. For the treatment of the plant with the insecticidal so lution, pieces of tobacco leaves (4.5cm diameter) were immersed in a solution of the pr epared insecticide solution (500ppm) for 30 seconds and dried in shade inside a hood. After preparing a disposable petri dish (6 cm diameter) lined with a filter paper, the tob acco leaves were added thereto followed by inoculation with ten adult green peach aphi ds. After 24 hours and 48 hours, respectively, the number of the alive insects was cou nted and the insecticidal activity was determined as percent value of dead number. As a standard insecticide (LC50 : 13.2 ppm), Acepate was used.

As a result, it was found that Compound Nos. 34, 45, 47, 53, 59 and 66 have an effective insecticidal activity.

Example 6: Activity on two-spotted spider mite {Tetranychus urticae)

An adult two-spotted spider mite was taken as a test subject and pieces of kidne y bean leaves were taken as a test plant. Cotton balls were placed over a petri-dish (6 cm diameter), which was then moistened by spraying water. Then, pieces of kidney b ean leaves (3.5cm diameter) were added thereto followed by inoculation with thirty adult two-spotted spider mites. Using a small spray, the insecticidal composition was appli ed thereto (500ppm). After 24 hours and 48 hours, respectively, the insecticidal ratio was determined. As a control, Dicofol (LC50 : 29.9 ppm) and Cyhexatin (LC50 : 11.8 ppm) were used.

As a result, it was found that Compound Nos. No. 3, 4, 6, 10, 13, 14, 15, 18, 31 , 34, 35, 45, 53, 59, 63 and 66 have an effective insecticidal activity. Example 7: lnsecticidal activity on two-spotted spider mite (Tetranychus u rticae) by Amitraz, /V-[(di-n-butylamino)sulfenyl]-Λ/'-(4-chloro-2-methylphenyl)-Λ/-m ethylformamidine (disclosed in USP No. 3,998,969) and the Compound No. 66 of t he present invention with various concentrations

As it is shown in the following Table 10, and the Compound No. 66 of the prese nt invention has an insecticidal activity on two-spotted spider mite (Tetranychus urticae) that is five to six times higher than that of Amitraz as a control and Λ/-[(di-n-butylamino) sulfenyl]-Λ/'-(4-chloro-2-methylphenyl)-Λ/-methylformamidine as a compound known in p rior art.

Table 10

Claims

1.

Fluorine-containing phenylformamidine derivatives which are represented by the following Chemical formula I: [Chemical formula I]

wherein,

R³ independently represent a hydrogen atom, a Ci_-2 alkyl group, an acetyl group, a carb o-C-ι-2 alkoxy group, or a Ci_-2 alkylcarbamoyl group], a carbo-Ci_-2 alkoxy group, a Ci_-2 al kylcarbamoyl group, a C₁-₄ alkyl group or alkoxy group [OR⁴: R⁴ represents a hydrogen atom, a Ci_-2 alkyl group, an acetyl group, a carbo-Ci_-2 alkoxy group, or a Ci_-2 alkylcarba moyl group];

R¹ represents a hydrogen atom, or a Ci_-4 alkyl group;

Y represents a Ci_-8 alkyl group, a dialkyl [R⁵, R⁶]aminosulfenyl group (R⁵ and R⁶ i ndependently represent a Ci_-8 alkyl group, a Ci_-6 haloalkyl group, or a C_5-6 cyclic alkyl gr oup) or a N-methyl-N-arylalkylaminosulfenyl group; and, n represents 1 , 2, 3 or 4.

2.

The fluorine-containing phenylformamidine derivatives according to Claim 1 , cha racterized in that when Y represents a dialkylaminosulfenyl group the derivatives are re presented by the following Chemical formula M: [Chemical formula II]

wherein,

F represents fluorine; X represents a cyano group, an amino group [NR²R³: R² and R³ independently r epresent a hydrogen atom, a Ci_-2 alkyl group, an acetyl group, a carbo-Ci_-2 alkoxy grou p, or a C-_I-2 alkylcarbamoyl group], a carbo-Ci_-2 alkoxy group, a Ci_-2 alkylcarbamoyl grou p, 2-C₁-₄ alkyl group or 2-alkoxy group [OR⁴: R⁴ represents a hydrogen atom, a Ci_-2 alkyl group, an acetyl group, a carbo-Ci_-2 alkoxy group, or a Ci_-2 alkylcarbamoyl group];

R¹ represents a methyl group; n represents 1 , 2, or 3; and

R⁵ and R⁶ independently represent a Ci_-8 alkyl group, a Ci_-6 haloalkyl group, a C ₅-₆ cyclic alkyl group, or an arylalkyl group.

3.

The fluorine-containing phenylformamidine derivatives according to Claim 2, cha racterized in that the compound that is represented by the Chemical formula Il is Λ/-[(di- alkylamino: R⁵, R⁶)sulfenyl]-Λ/'-(2,4,6-trifluorophenyl)-Λ/-methylformamidine.

4.

The fluorine-containing phenylformamidine derivatives according to Claim 2, cha racterized in that the compound that is represented by the Chemical formula Il is Λ/-[(di- alkylamino: R⁵, R⁶)sulfenyl]-Λ/'-(4-fluoro-2-methylphenyl)-Λ/-methylformamidine.

5.

The fluorine-containing phenylformamidine derivatives according to Claim 2, cha racterized in that the compound that is represented by the Chemical formula Il is Λ/-[(di- alkylamino: R⁵, R⁶)sulfenyl]-Λ/'-(4-fluoro-2-aminophenyl : NR²R³)-Λ/-methylformamidine.

6.

The fluorine-containing phenylformamidine derivatives according to Claim 2, cha racterized in that the compound that is represented by the Chemical formula Il is Λ/-[(di- alkylamino: R⁵, R⁶)sulfenyl]-Λ/'-(4-fluoro-2-alkoxyphenyl :OR⁴)-Λ/-methylformamidine.

7.

An agent for controlling pests comprising the fluorine-containing phenylformami dine derivatives according to any one of Claims 1 to 6 as an effective component.

8.

The agent for controlling pests according to Claims 7, characterized in that said pests are either Acarina or Acari mites.