JPS5877866A - Aminopyridazine derivative and herbicide - Google Patents

Abstract

NEW MATERIAL:An aminopyridazine derivative expressed by formulaI[R<1> is lower alkyl, lower alkenyl or lower alkynyl; R<2> is alkyl, lower alkenyl, (substituted)phenyl or (substituted)cyclohexyl; R<3> is lower alkyl; R<4> is halogen; however, R<1> and R<2> together form a substituent group expressed by formula II or III]. EXAMPLE:3-Chloro-4-methyl-6-(N-methylanilino)pyridazine. USE:A herbicide capable of exhibiting a powerful weeding activity against weeds of the family Cyperaceae, e.g. bulrush or water nutgrass, which are strongly injurious weeds in paddy fields and the selectivity for crops with low phytotoxicity to the crops. PROCESS:A pyridazine expressed by formula IV is reacted with an amine expressed by the formula R<1>R<2>NH in an inert solvent or under solventless conditions if necessary in the presence of an acid acceptor at 10 deg.C- the boiling point of the solvent to give the compound expressed by formulaI.

Description

[Detailed description of the invention] This relates to herbicides containing these as active ingredients.

Specifically, (in the formula, 11 is a lower alkyl group, a lower alkenyl group, or a lower alkynyl group, R2 is an alkyl group, a lower alkenyl group, a phenyl group, a substituted phenyl group, a cyclohexyl group, or a substituted cyclohexyl group, and M is a lower alkyl group) group, FL4 represents a halogen atom, R1 and R2
and N include the radicals formed by them and O N-.

) It relates to a herbicide characterized by containing a mononoaminopyridazine derivative and at least one thereof as an active ingredient.

Conventionally, the herbicidal activity of anilinopyridazines, pendylaminopyridazines, or alkylaminopyridazines has been reported in Japanese Patent Publication Nos. 19519-1982 and 43819-1989 entitled "Chemical Regulation of Plants". Volume 8 10
~20 pages (1975) and Journal of Medi-
cinal Chemistry) Volume 6, page 807 (
(1965).

As a result of long-term exploration and research into plant protection substances with pyridazine as the core, the present inventors discovered that the aminopyridazine derivative represented by the above general formula (1) has a very unique herbicidal activity. The present invention was completed.

More specifically, the present inventors have discovered that the novel compound of the present invention has surprisingly less phytotoxicity to crops than the previously known compounds, and has been found to be effective against weeds of the Cyperaceae family, such as Cyperaceae and Cyperaceae, which are harmful weeds in rice fields. The present invention was completed based on the discovery that it has a unique herbicidal activity, such as being highly effective against.

Namely, Special Publications No. 41-19519 and No. 47-43819
According to the publication, 3-chloro-6-substituted anilinoviridazine (referred to as "compound group A") represented by the general formula (in the formula, R represents a halogen atom, methyl group, or methoxy group) is harmful to plants. It has been described that it has physiological effects, but the physiological effects are tested in Petri dishes. In general, even if a physiological effect is expressed in a petri dish test, it is not expected that a pot test will show the same effect. In addition, the test plants were barnyard grass and Japanese radish, and there is no description of herbicidal effects on plants of the Cyperaceae family. Comparing the two structures, the compound of the present invention has substituents R1 and R2 as shown in general formula (1). Furthermore, there is a major difference in the structure of the invention in that the pyridazine ring has a substituent R3, and this difference in structure causes a difference in herbicidal effect between the present invention and compound group A, as shown in the test examples below. There is a surprisingly large difference in the selectivity for oak crops. ), compound group B has lower activity than C (・(activity of B,
However, as shown in the test examples below, the herbicidal activity of the compounds of the present invention is equivalent to or higher than that of compound group C. Unlike Compound Group B, which has one NH group, the compound of the present invention has substituents 31 and R2, as represented by the general formula (1), and has a high activity. On the other hand, compound group C is produced by adding and reacting the amines represented by the present invention (wherein R1 and R2 have the same meanings as above) to form an aminopyridazine represented by the general formula (1). The amines represented by the general formula (3) can be dissolved or suspended in the above-mentioned solvents, or the pyridazines represented by the general formula (2) can be added without a solvent and reacted. Preferably, the pyridazine is dissolved in the above-mentioned alcohol and 11 to 25 equivalents of the amine are added, or the pyridazine is added to an excess amount of the amine without a solvent and reacted. Any temperature below the boiling point of the solvent, preferably from 10°C to the boiling point of the solvent.

Although amines act as acid acceptors in the reaction, appropriate acid acceptors such as sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, sodium hydride, triethylamine, pyridine, etc. may be used as necessary. I can do it.

2) Using the method in l) above, calculate the general formula
1% formula % (4) (In the formula, R2 has the same meaning as above.)
Amine pyridazines represented by the general formula (wherein R2, R3 and R4 have the same meanings as above) are produced by reacting the amines represented by 4 with the pyridazines represented by the general formula (2). do.

Alternatively, the aminopyridazines represented by the general formula (5) can be dissolved in a suitable inert solvent, such as aromatic hydrocarbons such as benzene, toluene, and xylene, and ethers such as tetrahydrofuran, dioxane, and diinopropyl ether. Dissolved, suspended or without a solvent, a halide represented by the general formula % (6) (where Bl has the same meaning as above and X means a halogen atom) 10 equivalents, preferably) 11
~3 equivalents are added and reacted with a 10-50% aqueous sodium hydroxide or potassium hydroxide solution in the presence of a suitable 9-time transfer catalyst, such as triethylpendylammonium bromide, tetramethylammonium chloride, trioctylammonium chloride, etc. Then, the general formula (1
) indicated by Ao, Pi1, No2. Manufacture Gigi's. The reaction temperature is O'O or any temperature below the boiling point of the solvent or halide.

Typical compounds obtained by the above production method and their physical properties are shown in Table 1 below.

All active ingredient compounds in the following production examples, formulation examples, and test examples are indicated by compound numbers in Table 1.

Next, the method for producing the compound of the present invention represented by the general formula (1) will be explained in detail by giving a production example.

Production Example 1 Synthesis of 6-anilino-3-chloro-4-methylpyridazine 163 g of 3,6-dichloro-4-methylpyridazine and 500 ml of n-butanol were added to the reaction flask of 11, and while stirring under reflux, 952 g of aniline was added over 15 hours. dripped. The crude crystals were further heated under reflux for 1 hour, washed with water, and then dissolved in acetone (5e) with
04I was obtained. Yield 47.3%, mp175-176
°C0 Production Example 2 Synthesis of 3-chloro-4-methyl-6-(N-methylanilino)pyridazine (Compound No. 1) 110 g of 6-anilino-3-chloro-4-methylpyridazine and 200 g of benzene were placed in a 2001st reaction flask. 213 g of methyl iodide was added. A solution prepared by dissolving 6.8 g of triethylbenzylammonium bromide in 75 ml of a 25% aqueous sodium hydroxide solution was added to the mixture at room temperature while stirring thoroughly. After heating to 400C and stirring vigorously for 1 hour, the mixture was cooled and the benzene layer was separated, washed with water and dehydrated with anhydrous sodium sulfate, and the benzene was distilled off to obtain an oily substance.

This oil was purified by silica gel column chromatography (Wako gel 0-500, developing solution: toluene/ethyl acetate =
9/1) and purified with 3-chloro-4-methyl-6-(N
-methylanilino)pyridacyy 6.2 fl were obtained.

Yield 55%, mp 91.0-92.0C0 Production Example 34-tert-butyl-3-chloro-6-(N
-Synthesis of Methylanili/Noviridazine (Compound No. 2) Into a 100d reaction flask was added 4-tert-butyl-5
, 6-dichloropyridazine 5.59 and n-butanol 5
0 m/ was added, stirred under reflux, and aniline 27I was added dropwise. After further stirring at 110'O for 3 hours, n-
Butanol was distilled off, the residual oil was discharged into water, and the resulting crude crystals were collected and washed with water. The crystals were recrystallized and purified from ethanol to obtain 4.9v of 6-anili-4-tert-butyl-6-chloropyridazine. Yield: 70 cm.

6-anilino-4-ter in a 100 m/2 reaction flask
39y of t-butyl-3-chloropyridazine, 40ml of tetrahydrofuran (abbreviated as THF), and 40ml of methyl iodide
Added 2 wa. The mixture was thoroughly stirred at room temperature, and a solution of 2.0 g of triethylbenzylammonium bromide dissolved in 25 ml of an aqueous solution of 1 di-sodium 25-thihydroxide was added. After stirring vigorously at 35°C for 6 hours, the THF layer was separated, washed with water, and dehydrated with anhydrous sodium sulfate. THF was distilled off to obtain crude crystals. The crystals were recrystallized from petroleum benzine to give 2.5 g of 4-tert-butyl-3-chloro-
6-(N-methylanilino)pyridazine was obtained.

Production Example 4 Synthesis of 5-chloro-4-methyl-6-(N-methylanilino)pyridazine (Compound 1 No. 1) 3. 163 g of 6-dichloro-4-methylpyridazine was added to n
7236 g of N-methylanili was added dropwise to 50 ml of -butanol and dissolved while heating at 50°C, and the mixture was heated and stirred at 115°C for 5 hours. After n-butanol was distilled off under reduced pressure, the cooled reaction solution was discharged into water to obtain crystals. After washing the crystals with water and drying them, they were recrystallized with ethanol and 3-chloro-4
-Methyl-6-(N-methylanilino)pyridazine 17
5g was obtained. Yield 75% Production Example 5 Synthesis of 3-chloro-4-methyl-6-(N-methylcyclohexylamino)pyridazine (Compound No. 14) 3. 6-dichloro-4-methylpyridazine 5.017 and N-methylcyclohexyl Amine 1t3y and 5.217 ml of sodium carbonate were placed in a 5omi reaction vessel and heated with stirring at 150° to 155°C for 3 hours.

After cooling, the reaction solution was poured into water, the organic layer was extracted with benzene, the benzene layer was washed with water, dehydrated with sulfur and sodium chloride, and the benzene was distilled off to obtain an oily substance. This oil was subjected to silica gel column chromatography (developing solvent: benzene/
Purification was performed using ethyl acetate (9/1) to obtain 379 of the target compound. Yield: 52 cm.

Other compounds shown in Table 1 above can also be produced according to any of Production Examples 2 to 5.

For the compound of the present invention, the active ingredient compound represented by the above general formula (1) may be used as it is, but generally, depending on the purpose of use, it may be dissolved or dissolved in a suitable liquid carrier (for example, an organic solvent). Dispersed or mixed or adsorbed onto a suitable solid carrier (eg diluent, filler). At that time, various auxiliary agents (e.g. emulsifiers, stabilizers,
By appropriately adding dispersants, suspending agents, spreading agents, wetting agents, penetrants, etc., it can be used in various dosage forms such as emulsions, irrigation agents, granules, and powders.

The herbicide of the present invention includes one or more other herbicides, insecticides, fungicides, plant growth regulators, etc., soil conditioners,
Alternatively, it is possible not only to use it in combination with fertilizing substances, but also to prepare mixed preparations with these substances.

The content of the active ingredient of the herbicide of the present invention is 1 to 10 in the case of granules.
H. 20-80% for irrigation agents, 10-50% for emulsions (
% by weight) is desirable.

Next, examples of formulations of herbicides containing the compound of the present invention as an active ingredient will be shown, but the present invention is of course not limited to these.

Formulation Example 1, 15 parts of granule compound, 72 parts of bentonite, 20 parts of talc, 2 parts of sodium dodecylbenzene sulfonate and 1 part of sodium lignin sulfonate were mixed, an appropriate amount of water was added and kneaded, and then extruded. Granulate using a granulator in the usual manner,
100 parts of granules were obtained.

Formulation Example 2 Wettable powder 10 was prepared by mixing and pulverizing 50 parts of wettable powder compound 4, 40 parts of diatomaceous powder, and 10 parts of sodium doersolhensulfonate.
I got 0 copies.

Test Example 1 Paddy field weed control test R/5 tlOO Wagner pots were filled with soil, and seeds of Japanese millet, firefly, water cyperus, and cyper spp. Two 21 plants were transplanted and grown in a greenhouse.

Three days after transplanting paddy rice, at the beginning of weed emergence, a predetermined amount of the test compound was submerged in water using a granule according to the method described in Example 1 above. One month after the treatment, weed growth and chemical damage to paddy rice were investigated, and the results shown in Table 2 were obtained. In this table, the degree of chemical damage to crops and the herbicidal effect on weeds were expressed by comparing the emergence or growth of crops or weeds with the air-dried type in the untreated area, and expressed according to the evaluation criteria below.

The test compounds are indicated by compound numbers in Table 1.

Evaluation criteria 0: Survival rate expressed as air dry weight ratio vs. untreated area 91-100
41 61-90
%2 51~6o
Ciro 11~5
o 46-10% 50-5
-(2-methylanilino)pyridazine.

*25-(2-methylphenoxy)pyridazine (representative compound of compound group 0).

Test Example 2 Field Crop Weed Control Test Earl/soo o Cottontail pots were filled with soil, and seeds of soybean, cotton, corn, cyperus japonica, and Japanese commonweed were sown.

Three days after sowing, a predetermined amount of the test compound was added per are using an irrigation agent prepared according to the method of Example 2.
The solution was diluted with an amount of water equivalent to 0.01 and sprayed using a micro-pressure sprayer.

This was grown in a greenhouse. Thirty days after the chemical spraying, the appearance and growth of crops and weeds was investigated, and the results shown in Table 3 were obtained.

In this table, the classification of growth states of crops and weeds and the test compound numbers are the same as in Table 1.

Claims (1)

[Scope of Claims] (1) General formula (wherein R1 is a lower alkyl group, lower alkenyl group, or lower alkynyl group, R2 is an alkyl group, -lower alkenyl group, phenyl group, substituted phenyl group, cyclohexyl group, or An amine l pyridazine derivative represented by a substituted cyclohexyl group, R3 is a lower alkyl group, R4 is a 710-gen atom, and R1, R2, and N include groups formed by them (-)- and 0-. (2) R1 is a methyl group, an ethyl group, an inpropyl group,
Claim 1, wherein R2 is an allyl group or a propalkyl group, R2 is an ethyl group, n-butyl group, allyl group, or phenyl group, R3 is a methyl group or a tert-butyl group, and R4 is a chlorine atom. Compounds described in Section. (5) R1 is a methyl group, ethyl group, or isopropyl group, I'L2 is an n-butyl group, phenyl group, or substituted phenyl group, R3 is a methyl group or tert-butyl group, and R4 is a chlorine atom. A compound according to claim 1. (4) R1 is a methyl group, ethyl group or inpropyl group, R2 is a cyclohexyl group or substituted cyclohexyl group, R3 is a methyl group, and R4 is a chlorine atom, according to claim 1. Compound. (5) R2 and R2 are different lower alkyl groups, and R
The compound according to claim 1, wherein 3 is a methyl group and R4 is a grapheme element. (In the formula, R1 is a lower alkyl group, lower alkenyl group, or lower alkynyl group, R2 is an alkyl group, lower alkenyl group, phenyl group, substituted phenyl group, cyclohexyl group, or substituted cyclohexyl group, R3 is a lower alkyl group, A herbicide characterized in that IIL4 each represents a halogen atom, and R1, R2, and N each contain at least one aminopyridazine derivative formed by these as an active ingredient.