JPS591469A - Pyridazine derivative and selective herbicide - Google Patents

Abstract

NEW MATERIAL:A pyridazine derivative expressed by formula I [X is O or S; R1 is alkyl; R2 is (substituted) alkyl or alkoxyl; R3 is H, halogen, alkyl or alkoxyl; R4 is halogen, methyl, methoxyl or trifluoromethyl; n is an integer 0, 1 or 2 except when R1 and R2 are methyl, R3 is H,X is O and n is 0]. EXAMPLE:4-Methyl-3-methylthio-6-phenylpyridazine. USE:An easily usable selective herbicide having definite effects. PROCESS:A compound expressed by formula II is reacted with a compound expressed by the formula R1XNa in an organic solvent to give the aimed compound expressed by formula I .

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel compound and its use, and specifically relates to a compound represented by the general formula (1) (wherein, X is O or S, R1 is a lower alkyl group, R2
is a lower alkyl group, a lower alkoxy group, or a lower alkyl group substituted with a halogen atom, a lower alkoxy group, or a lower alkoxycarbonyl group, R3 is a hydrogen atom, ... a rogen atom, a lower alkyl group, or a lower alkoxy group , R4 represents...a rogen atom, a methyl group, a methoxy group, or a trifluoromethyl group, and n represents 011 or 2. ) and selective herbicides containing the compounds as active ingredients.

The object of the present invention is to provide a herbicide that can be industrially advantageously obtained, is easy to use, and is reliably effective.

The present inventors synthesized a large number of pyridazine derivatives and examined those suitable for the above purpose, and found that the general formula (1)
The inventors discovered that the compound represented by the following shows excellent herbicidal activity and has almost no toxicity to humans, animals, fish, and shellfish, and after conducting further biological and physicochemical research, they completed the present invention.

It was disclosed in JP-A-49-1996 that phenylpyridazine derivatives similar to the compounds of the present invention have plant growth inhibiting and herbicidal effects.
No. 48837, No. 80245, No. 50-35339, etc., but the compound of the present invention has far superior herbicidal activity compared to known compounds.

Among the compounds according to the present invention, 3-methoxy4-methyl-6
-Phenylpyridazine is a known compound (Ber,
34 P 4233 (1901)), nothing is known about its biological activity. The compound of the present invention is a compound represented by the general formula (wherein R2, R3, R4 and h have the same meanings as above) and a compound represented by the general formula RIXNa(m).
(In the formula, R1 has the same meaning as above.) It can be produced by reacting the compound represented by the following in an organic solvent. (Hereinafter referred to as production method ■) However, depending on the substituents of R2, R3, and R4, the production of the raw material compound represented by the general formula (If) may be complicated, and in that case, the method shown in the reaction formula below may be used. It can also be manufactured by

(In the formula, R1, R4 and n have the same meanings as above,
R'3 represents a hydrogen atom or ).rogen atom, R'2 represents a lower alkyl group, and R2 represents a no-roalkyl group. )(
The manufacturing method will be referred to as ■ below. ), R'2 represents a lower alkyl group, and T and r' represent a lower alkyl group. ) (Hereinafter referred to as manufacturing method ■) ■ (In the formula, R4 and n have the same meanings as above, and R represents a lower alkyl group.) (Hereinafter referred to as manufacturing method ■.) (In the formula, X and R1 has the same meaning as above, and R'2
H represents a lower alkyl group, a lower alkoxy group or a haloalkyl group, and R'3 represents a hydrogen atom,...a rogen atom or a lower alkyl group. ) (Hereinafter referred to as the manufacturing method ■) ■ (In the formula, R represents a lower alkyl group.) (Hereinafter referred to as the manufacturing method ■) ■ (Hereinafter referred to as the manufacturing method ■) Reaction of the compound ■ with the compound ■ ( Production method ①) uses an aprotic polar solvent such as dimethylformamide or dimethyl sulfoxide, or an alcohol represented by R10H when X=0 (R1 has the same meaning as above), when X=s. In some cases, water can be used as a solvent. The reaction is completed in 1 to several hours at room temperature to 100°C. After the reaction is completed, the desired product can be obtained by performing usual post-treatments such as pouring the reaction solution into ice water and extracting the separated oil or crystals with a solvent or filtering.

Next, the method for producing the compound of the present invention will be explained with reference to production examples.

Example 1 Compound 4I 4-Methyl-3-methylthio-6-phenylpyridazine 3-chloro-4-methyl-6-phenylpyridazine 6
F was dissolved in 60 liters of ethanol, 154 liters of an aqueous solution of sodium methyl mercaptan (2(1)) was added, and the mixture was heated under reflux for 1 hour.Then, it was poured into water and extracted with ethyl acetate. After drying the organic components, the solvent was distilled off. The desired product 5.42 was obtained.Yield: 85.2cm White crystals m, p-59~62°C Example 2 Compound 7 6-(3-bromophenyl)-3-methoxy-4-methylpyridazine°5o 3F of 3-methoxy-4-methyl-6-phenylpyridazine and 3F of N-promoco/phosphoric acid imide were added to 30ml of sulfuric acid and kept at 65-70°C for 3 hours with stirring.Then, it was poured into ice water and neutralized with NaOH. After extraction with ethyl acetate and evaporation of the solvent, the residue was purified by silica gel column chromatography (benzene:ethyl acetate 9:1) to obtain 1.2t of the target product.Yield: 478cm white crystals m, p.
49-51℃ Example 3 Compound 30 4-dibromomethyl-3-methoxy-6-phenylpyridazine: Dissolve 22 of 3-methoxy-4-methyl-6-phenylpyridazine in 30 of benzene and add 161 of bromine. It was heated to 40-50°C for 3 hours. After that, it was poured into water and extracted with 50% of ethyl acetate to separate the organic elements, and after drying, the solvent was distilled off and the resulting residue was purified with silica gel column chromatography (hexa/4, ethyl acetate: 1) to obtain the target product 04v ( Recovery of raw material iF) was obtained. White crystals m, p, 95-97°C Example 4 Compound 31 5-chloro-3+4+-dimethoxy-6-phenylpyridazine Metallic sodium 0.9v in methanol 100-
A sodium methylate solution prepared by dissolving 3.4.5-trichloro-6- was cooled to 0°C and stirred at the same temperature.
Add phenylpyridazine 51 little by little and heat to 10-20°C.
Stirring was continued for 1 hour at 50° C. for 30 minutes. After that, it was poured into ice water, the precipitated crystals were taken out, and after drying, Ligroin 20
The solution was heated and dissolved in -, allowed to cool to room temperature, the precipitated crystals were removed by filtration, and the solvent of the mother liquor was distilled off to obtain the desired product 2.2f. Yield 45.5% white crystals m, p, 56-58°C Example 5 Compound 32 Methyl (3-methoxy-6-phenyl-4-pyridazinyl) acetate; 5f of oily sodium hydride was made cloudy, heated to 80°C in a nitrogen stream, and dried while stirring.
MF 30 mM, 3- dissolved in dimethyl carbonate 2°V
Methoxy-4-methyl-6-phenylviridadi/101
- solution was added dropwise over 30 minutes. After that, stirring was continued at the same temperature for 3 hours, then cooled to room temperature, poured into ice water, neutralized with acetic acid, and extracted with ethyl acetate. f
An oily target product 6V was obtained. Yield 46.5% Colorless transparent oil n'1.5836 Example 6 Compound 34 3.4-Dimethoxy-6-7enylpyridazine; Ethanol 80ml! 5-chloro-3,4-dimethoxy-
Dissolve 1.75 f of 6-phenylpyridazine 1.1 F of citriethylamine, 1 (l palladium on carbon 0.2
Hydrolysis was carried out at room temperature and pressure in the presence of f. Hydrogen was passed through the solution until no more hydrogen was absorbed, then the insoluble matter was removed by filtration, the ethanol was distilled off, the resulting residue was dissolved in chloroform, washed with water, and dried, and the chloroform was distilled off to obtain the desired product 1.
I got 32. Yield 86% white crystals m, p-111~11
2°C Example 7 Compound 36 3.4.5-) Dimethoxy-6-phenylpyridazine 3.41 in a sodium methylate solution prepared by dissolving 1.8 f of metallic sodium in 50 mf1 of methanol
5-trichloro-6-phenylpyridazine 5f was added, and the mixture was heated under reflux for 5 hours with stirring. Thereafter, the mixture was poured into ice water and extracted with chloroform. After drying the organic components, the solvent was distilled off to obtain the desired product 4.2f as a pale yellow oil.

Yield 90% Pale yellow oil n%' 1.5883 Table 1 shows representative examples and physical constants of the compounds of the present invention.

Table 1 When the compounds of the present invention are sprayed on the foliage of weeds during the growth period after germination, they exhibit high herbicidal effects, especially against broad-leaved weeds such as red snail, knotweed, and chickweed, even at extremely low doses. For peanuts, the amount of drug that kills weeds is 2.
Even when ~4 times the amount is applied to the foliage, almost no adverse effect is observed, and it has extremely high selectivity between weeds and peanuts. The present compound also has selectivity for rice and wheat, particularly for rice, for example at 100 t/10a.
It has the effect of killing a wide range of paddy field weeds without causing any chemical damage to rice at low doses, and has extremely high selectivity between rice and weeds.

The herbicide of the present invention contains one or more of the compounds represented by the general formula (I) as an active ingredient, and has the same form as a common agricultural chemical. That is, the active ingredient compound is generally used by mixing an appropriate amount with a carrier and preparing it in the form of a wettable powder, emulsion, granule, or the like. Examples of solid carriers include talc, white carbon, bentonite, clay, and diatomaceous materials, and liquid carriers include water, alcohol, benzene, xylene, kerosene, mineral oil, cyclohexane, cyclohexanone, dimethylpolamide, and the like.

If necessary, a surfactant may be added in order to obtain a uniform and stable form in these preparations.

The concentration of the ringing component in the herbicide of the present invention varies depending on the form of the formulation described above, but for example, in the case of a wettable powder, it ranges from 5 to 70%, preferably from 10 to 5C1,
Concentrations of 5 to 40%, preferably 10 to 30%, are used in emulsions.

Irrigation agents and emulsions obtained in this way are diluted with water to a predetermined concentration to form a suspension or emulsion, which can be sprayed or mixed into the soil before weed germination, or sprayed on foliage after weed germination. It is processed. When actually applying the herbicide of the present invention, an appropriate amount of the active ingredient is applied in an amount of 30 f or more, preferably 50 f or more per 10 are.

In addition, the herbicide of the present invention is a known bactericide, insecticide, acaricide,
It can also be used in combination with herbicides, plant growth regulators, etc. In particular, when used in combination with herbicides, not only can the amount of chemicals used be reduced and labor-saving, but even higher effects can be expected due to the synergistic action of both chemicals. Examples of drugs suitable for mixed use with the herbicide of the present invention include 2
-(1-allyloxyaminobutylidene)-5,5-dimethyl-4-methoxycarbonyl-cyclohexane-1
, 3-dione sodium salt (Fusagad), 2-(
N-ethoxybutyrimidoyl)-5-(2-ethylthiopropyl)-3-hydroxy-2-cyclohexene-1
cyclohexanedione herbicides such as -one, phenoxyphenoxyalkane carboxylic acid herbicides such as iloxane and alopex, pyridyloxy such as butyl 2-(4-(6-)lifluoromethyl-2-pyridyloxy)phenoxy]propionate, etc. - Phenoxypropionic acid herbicides, etc. can be used.

Next, some formulation examples regarding the herbicide of the present invention will be shown, but the ratio of active ingredients, types of additives, and addition ratios are not limited to the present formulation examples and can be varied within a wide range.

Formulation Example 1 Hydrating Agent Compound No. 1 40 parts
10 parts diatomaceous earth 10 parts white carbon 30
polyoxyethylene alkylaryl ether sulfonate
10 parts or more are mixed uniformly and finely ground to obtain 4 active ingredients.
0% irrigation agent was obtained.

Formulation Example 2 Emulsion Compound No. 6 30 parts xylene 50 parts dimethylformamide 1
0 parts polyoxyethylene phenyl ether
At least 10 parts were mixed and dissolved to obtain an emulsion containing 30 parts of the active ingredient.

Formulation Example 3 Granules Compound No. 11 7 parts Tal
ri 38
Department -
38 parts bentonite 10 parts alkyl sulfate soda 7 parts or more are mixed uniformly and finely ground, with a diameter of 0.5 to 1. Otran
The mixture was granulated to obtain granules containing 7% of the active ingredient.

Next, test examples regarding the effect of the herbicide of the present invention will be shown.

Test Example 1 Efficacy Test 2 An oocfIi pot was filled with soil, and seeds of crabgrass, oat, pigweed, and goldenrod were sown on the surface layer and grown in a greenhouse. When each weed grows to a height of about 4 to 13 inches, the emulsion of each test compound is diluted with water to prepare a chemical solution with a predetermined concentration (in this case, 4000.2000 ppm).
was sprayed on the foliage of weeds using a small sprayer at a rate of 100 t/10a. Three weeks later, the growth status of weeds was investigated.

The investigation method was conducted by inspection according to the standards shown below, and the second
The results shown in the table were obtained.

Damage rate 0: 0% 2: 20~30chi 4: 40~50% 6゛60~70% 8: 85~95% 10: 100chi Also, the display of 1, 3, 5, 7, and 9 is 0 respectively. 2.2 and 4.
It shows a value between 4, 6.6, 8.8 and 10.

Table 2 Test Example 2 Crop Phytotoxicity Test A 100crA bottle was filled with soil, and seeds of corn, wheat, sugar beet, soybean, and peanuts were sown separately.
Grown in a greenhouse. When the crop has grown to the 1st to 3rd leaf stage, a chemical solution with a predetermined concentration (4000 ppm and 2000 ppm in this case) prepared by diluting the emulsion of each test compound with water is prepared.
was sprayed onto the foliage of the crops using a small sprayer at a rate of 100 t/10a. Three weeks later, the growth status of the crops was investigated. The growth conditions were investigated according to the same criteria as Test Example 1, and the results shown in Table 3 were obtained.

Table 3 Test Example 3 Paddy soil was put into a 100crA bottle, and seeds of Japanese wild grass, Japanese cypress, Japanese cypress, Japanese firefly, and Omodaka were sown.

After 18 days, rice plants at the 3rd to 4th leaf stage were transplanted, and on the next day, the water depth was maintained at 3 parts, and the granules of the test compound formulated according to the formulation of Formulation Example 3 were treated with 100 f/10a maggots. Three weeks later, the growth status of rice and weeds was investigated, and the results are shown in the fourth page. The investigation criteria were the same as in Test Example 1.

Applicant 2: Nippon Soda Co., Ltd. Agent: Haruyuki Ito: Yoshimi Yokoyama Procedural amendment dated February 7, 1982 Kazuo Wakasugi, Commissioner of the Patent Office 1 Indication of case 1989 Patent Application No. 102982 2, Title of the invention Pyridazine Derivatives and Selective Herbicides 3 Relationship with the Amended Person Case Patent Applicant Address: 430 2-2-1 Otemachi, Chiyoda-ku, Tokyo 100
) Nippon Soda Co., Ltd. Representative Takeo Sannomiya 4 Agent Address: 2-2-1 Otemachi, Chiyoda-ku, Tokyo 100 Nippon Soda Co., Ltd. Tel: (245) 6234 (2) Specification Column 6 for detailed description of the invention; Contents of the amendment (1) Description of the appendix to the scope of the specification and claims (2) Correct 6 lines from the bottom of page 8 of the specification "Organic genus" to 1 line "Organic layer".

(3) "Manufacturing method" in Table 1 on pages 13, 14, 15 and 16 of the specification is corrected to "manufacturing method".

(4) In the 8th line from the bottom of page 16 of the specification, ``Pigweed, Pigweed'' is corrected to ``Pigweed, Pigweed.''

(5) Correct "Alopex" in line 2 on page 19 of the specification to "Alopex".

(6) Line 1 from the bottom of page 27 of the specification [*Control compound:
*Corrected to ``Control compound: Same as Test Example 1''.

(7) In the fourth line from the bottom of page 28 of the specification, "*Control compound: Same as Test Example 2" is corrected to "*Control compound;".

Claims (In the formula, X is 0 or S; R3 is a lower alkyl group; R3 is a hydrogen atom, a halogen atom, a lower alkyl group, or a lower alkoxy group.
4 represents a halogen atom, a methyl group, a methoxy group, or a trifluoromethyl group, and n represents 0.1 or 2. However, R1
and R2 is a methyl group, R3 is a hydrogen atom, and X is 01n=
Except when o. ).

(2) R1 is a methyl group or an ethyl group, R2 is a methyl group,
Ethyl group or methoxy group, R3 is hydrogen atom, halogen atom, methyl group or methoxy group, R4 is chlorine atom, bromine atom, methyl group, methoxy group or trifluoromethyl group,
The compound according to claim 1, wherein n is 0, 1 or 2.

(3) General formula (wherein, X is O or S, R1 is a lower alkyl group, R2
is a lower alkyl group, a lower alkoxy group, or a lower alkyl group substituted with a halogen atom, a lower alkoxy group, or a lower alkoxycarbonyl group, R3 is a hydrogen atom,
R4 represents a halogen atom, a lower alkyl group or a lower alkoxy group, R4 represents a halogen atom, a methyl group, a methoxy group or a trifluoromethyl group, and n represents 0.1 or 2. ) A selective herbicide characterized by containing a compound represented by the following as an active ingredient.

Claims (1)

[Scope of Claims] (In the formula, an alkyl group, R3 is a hydrogen atom,)
R4 represents a halogen atom, a lower alkyl group, or a lower alkoxy group, and n represents a halogen atom, a methyl group, a methoxy group, or a trifluoromethyl group. however,
R1 and R2 are methyl groups, R3 is hydrogen atom, n =
Except when O. ). 2, R is a methyl group or an ethyl group, R2 is a methyl group, an ethyl group, or a methoxy group, R3 is a hydrogen atom, a halogen atom, a methyl group, or a methoxy group, and R4 is a chlorine atom, a bromine atom, a methyl group, a methoxy group, or trifluoromethyl group, n
The compound according to claim 1, wherein is Oll or 2. (In the formula, X is 0 or S, R1 is a lower alkyl group, R
2 is a lower alkyl group, a lower alkoxy group, or a lower alkyl group substituted with a halogen atom, a lower alkoxy group, or a lower alkoxycarbonyl group; R3 is a hydrogen atom, a halogen atom, a lower alkyl group, or a lower alkoxy group; R4 is a lower alkyl group; n represents a halogen atom, methyl group, methoxy group or trifluoromethyl group; n represents 0, 1 or 2; ) A selective herbicide characterized by containing a compound represented by the following as an active ingredient.