JPH04330067A - 1,3,4-thiadiazole derivative, its production and herbicide - Google Patents

Abstract

PURPOSE:To obtain a novel compound having selectivity and low toxicity as a herbicide. CONSTITUTION:A compound [e.g. N-methyl-2-(2-2,2,2-trifluoroethoxy-1,3,4- thiadiazol-5-yloxy)-acetanilide] expressed by formula I (R<1> is fluorine-substituted alkyl; R<2> is lower alkyl or lower alkenyl; R<3> is phenyl, etc.). The compound is obtained by reacting a compound expressed by formula II (X is chlorine or bromine) with a compound expressed by formula III and reactive derivative thereof (e.g. sodium alcolate) using a solvent such as DMF.

Description

[Detailed description of the invention]

0001

FIELD OF THE INVENTION The present invention relates to a novel 1,3,4-thiadiazole derivative useful as a herbicide, a method for producing the same, and a herbicide containing the 1,3,4-thiadiazole derivative as an active ingredient.

0002

[Prior Art] Various azole derivatives have been proposed as herbicides, for example, in JP-A-54-1547.
In Publication No. 62, general formula (IV)

The substituted carboxylic acid amide represented by the formula (V) and its use as a herbicide are described in JP-A-55-147267.

Azolyloxycarboxylic acid amides of the formula [Image Omitted] and their use as herbicides are disclosed.

0003

[Problems to be Solved by the Invention] However, even these compounds are not necessarily fully satisfactory in terms of herbicidal activity, phytotoxicity, etc.; It is desired to provide herbicides that are adaptable to useful crops.

0004

[Means for Solving the Problems] The present inventors have created various novel azole derivatives that have not existed before, and have investigated their herbicidal activity.
It was discovered that 3,4-thiadiazole derivatives have excellent properties such as herbicidal activity and herbicidal selectivity against various plants, and are low in toxicity.As a result of various studies, the present invention was completed.

The first aspect of the present invention is the general formula (I
)

embedded image (wherein, R1 represents fluorine-substituted alkyl, R2 represents lower alkyl or lower alkenyl, R3 represents optionally substituted phenyl, or R2 and R3
together with the nitrogen atom to which they are attached represent a heterocyclic group. ) [hereinafter referred to as compound (I)].

[0006] The second invention of the present invention is the general formula (I
I)

embedded image (wherein, R2 is lower alkyl or lower alkenyl, R3 is optionally substituted phenyl, or R2
and R3 together with the nitrogen atom to which they are bonded represent a heterocyclic group. X represents a halogen atom. ) and a compound represented by the general formula (III) R1 OH (III) (wherein R1 represents a fluorine-substituted alkyl) or a reactive derivative thereof. ).

The third invention relates to a herbicide containing at least one selected from compound (I) as an active ingredient.

[0008] In this specification, the fluorine-substituted alkyl may be either linear or branched, and usually has 1 to 4 carbon atoms, and all or some of the hydrogen atoms are substituted with fluorine atoms. It is what was done. Examples of fluorine-substituted alkyl include difluoromethyl, trifluoromethyl, 2,2-difluoroethyl, 2,2,2-trifluoroethyl, 2,2,3,3,3-n-pentafluoropropyl, 2,2 , 3,3-n-tetrafluoropropyl, 2,2,3,3,4,4,4-n-heptafluorobutyl, and the like.

[0009] In this specification, lower alkyl may be linear or branched, and usually has 1 to 4 carbon atoms.
It is individual. Examples of lower alkyl include methyl, ethyl, isopropyl, n-propyl, and n-butyl.

[0010] In this specification, the lower alkenyl may be linear or branched, and the number of carbon atoms thereof is usually 1 to 1.
There are 4 pieces. Examples of lower alkenyl include allyl,
Examples include propenyl.

[0011] In this specification, the substituent for phenyl which may be substituted includes, for example, a group having 1 to 4 carbon atoms.
Examples include lower alkyl, lower alkoxy having 1 to 4 carbon atoms, halogen atom, cyano, fluorine-substituted lower alkyl, nitro, etc., and the number of substituents is usually 1 to 3, preferably 1 or 2. . Examples of the phenyl include phenyl, 3-methylphenyl, 3-chlorophenyl,
3-methoxyphenyl, 3-ethylphenyl, 3-fluorophenyl, 3-cyanophenyl, 3-ethylphenyl, 3-trifluoromethylphenyl, 3-nitrophenyl, 2-ethylphenyl, 2,3-dimethylphenyl, Examples include 2,3-dichlorophenyl.

[0012] In this specification, the heterocyclic group formed by R2 and R3 together with the nitrogen atom to which they are bonded may be either saturated or unsaturated,
It is preferably a 4- to 6-membered ring or a condensed ring thereof, and may further contain an oxygen atom or a sulfur atom in addition to the nitrogen atom described above. The heterocyclic group may have a substituent, and examples of the substituent include lower alkyl having 1 to 4 carbon atoms, lower alkoxy having 1 to 4 carbon atoms, cycloalkyl having 3 to 6 carbon atoms, lower alkoxy-carbonyl having 1 to 4 carbon atoms,
Examples include lower alkanoyl having 1 to 4 carbon atoms, lower alkanoyloxy having 1 to 4 carbon atoms, and the number of substituents is usually 1 to 3, preferably 1 or 2. Such heterocyclic groups include, for example, piperidino, 2-methylpiperidino, 3-methylpiperidino, 2-ethylpiperidino, 3,5-dimethylpiperidino, 4-acetoxypiperidino, 4-ethoxycarbonylpiperidino, 4-benzyl piperidino, tetramethyleneimino, hexamethyleneimino, morpholino, 2,6-dimethylmorpholino,
4-formylpiperazino, 4-cyclopentanepiperazino, 4-pyridylpiperazino or a compound represented by the following formula

[Chemical formula 9] etc.

Compound (i) of the present invention can be produced, for example, by the following method. General formula (II)

embedded image (wherein, R2 is lower alkyl or lower alkenyl, R3 is optionally substituted phenyl, or R2
and R3 together with the nitrogen atom to which they are bonded represent a heterocyclic group. X represents a halogen atom such as chloro or bromine) [hereinafter referred to as compound (
II)] and a compound represented by the general formula (III) R1 OH (III) (wherein R1 represents a fluorine-substituted alkyl group) or a reactive derivative thereof (for example, an alcoholate such as sodium alcoholate) [hereinafter, These compounds are collectively referred to as compound (III)], R1 OH (
In the formula, R1 has the same meaning as above, and examples of the compound include 2,2,2-trifluoroethanol, 2,
2-difluoroethanol, 2,2,3,3-tetrafluoro-1-propanol, 2,2,2,3,3-pentafluoro-1-propanol, 2,2,3,3,4,
4,4-hexafluoro-1-butanol), dimethylformamide (DMF), dioxane, etc. as a reaction solvent from -20°C to the reflux temperature of the solvent.
It can be produced by reacting for ~48 hours and treating the resulting product according to a conventional method. Here compound (III)
It is preferable to use 1 to 2 times the molar amount of compound (II).

Compound (II) and compound (III) used as raw materials are substantially known compounds,
It can be manufactured by a known method or a method analogous thereto.

[0015]

Effect of the Invention The compound (I) of the present invention has high and wide-ranging herbicidal activity, and has low phytotoxicity and low toxicity. More specifically, the compound (I) of the present invention is effective against monocotyledonous and dicotyledonous weeds, for example, paddy field weeds such as Poaceae weeds such as Japanese millet, broad-leaved weeds such as Aspergillus spp. It exhibits excellent herbicidal effects against weeds such as crabgrass and sycamore. On the contrary, at herbicidal doses, there is no or almost no phytotoxicity to useful plants such as rice, wheat, soybean, and cotton, and even if there is phytotoxicity, it can be easily recovered.

Furthermore, the compound (I) of the present invention has low toxicity to humans, livestock, poultry, etc., and low toxicity to fish, so it is excellent in safety and has extremely low residual toxicity.

When the compound (I) of the present invention is used as a herbicide, it may be mixed with a solid carrier, a liquid carrier, a combination carrier of solid and liquid, a surfactant, and other formulation auxiliaries as necessary. It is used by formulating powders, granules, emulsions, wettable powders, suspensions, etc.

Compound (I) of the present invention in these preparations
The blending amount is 1 to 80% by weight, preferably 1 to 50% by weight.
%.

Examples of the solid carrier include clay (kaolin clay, attapulgite clay, etc.), bentonite,
Examples include fine powders or granules such as acid clay, birophyllite, talc, diatomaceous earth, silicate earth, calcite, walnut powder, urea, ammonium sulfate, and hydrous amorphous silicon oxide.As the liquid carrier, water, benzene, Aromatic hydrocarbons such as toluene, xylene, and methylnaphthalene, alcohols such as isopropanol, ethylene glycol, and cellosolve, ketones such as acetone, cyclohexanone, and isophorone, vegetable oils such as soybean oil and cottonseed oil, dimethyl sulfoxide, acetonitrile, cyclohexane, etc. can be mentioned.

As surfactants, anionic surfactants such as alkyl sulfates, alkyl (aryl) sulfonates, dialkyl sulfosuccinates, polyoxyethylene alkylaryl ether phosphates, and polyoxyethylene alkyl ethers, Examples include nonionic surfactants such as polyoxyethylene alkylaryl ether, polyoxyethylene polyoxypropylene block copolymer, sorbitan fatty acid ester, and polyoxysorbitan fatty acid ester. The surfactant is
It exhibits effects such as emulsification, dispersion, and wetting.

Other formulation aids such as emulsifiers, stabilizers, dispersants, suspending agents, spreading agents, penetrants, wetting agents, etc. can be added, such as lignin sulfonates, alginates, polyvinyl alcohols, etc. , gum arabic, CMC (carboxymethyl cellulose), PAP (isopropyl acid phosphate), polyoxyethylene resin acid (ester),
Abietate, dinaphthylmethane disulfonate, etc. may be used depending on the purpose of application.

[0022] Further, by mixing it with other herbicides and using it, it is expected that the herbicidal efficacy and herbicidal spectrum will be expanded.

Furthermore, it can be used in combination with insecticides, acaricides, nematicides, fungicides, plant growth regulators, fertilizers, soil conditioners, and the like.

The compound (I) of the present invention can be used in agricultural land such as paddy fields, fields, pastures, orchards, and tea plantations, as well as non-agricultural land such as railways, roads, riverbeds, lawns, open spaces, developed lands, parking lots, and parks. It can be used as a pre-emergent and post-emergent treatment herbicide.

The target soils are normal soils such as sandy loam and loam, planted soil, and sandy soil.

[0026] These preparations are generally used for foliage treatment or soil treatment, and in the case of soil treatment, the preparations are sprayed on the soil surface (if necessary, they are mixed with the soil after spraying). .

When the compound (I) of the present invention is used as an active ingredient of a herbicide, the amount of application varies depending on the purpose of use, the period of use of the target weeds, etc., but is usually 1 to 1 per 10 ares.
It is 500 g, preferably 3 to 100 g, and can be used diluted or undiluted.

[0028]

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples. Example 1 N-methyl-2-(2-2,2,2-trifluoroethoxy-1,3,4-thiadiazol-5-yloxy)
-Production of acetanilide After dissolving 0.33 g of metallic sodium in 10 ml of 2,2,2-trifluoroethanol, N-methyl-2-(
2 g of 2-chloro-1,3,4-thiadiazol-5-yloxy)-acetanilide was added at room temperature and stirred for 24 hours. The solvent was distilled off under reduced pressure, water was added, and 50ml of toluene was added.
Extracted with l. The extract was washed twice with water and then dried over anhydrous magnesium sulfate.

After distilling off toluene under reduced pressure, the residue was purified by silica gel chromatography (toluene and chloroform) to obtain N-methyl-2-(2-2,2,2-trifluoroethoxy-1,3,4 -thiadiazole-5
-yloxy)-acetanilide 1.8g (yield 73%)
) was obtained.

Example 2 2-(2-2,2,2-trifluoroethoxy-1,3
, 4-Thiadiazol-5-yloxy)-acetopiperidide After dissolving 0.14 g of metallic sodium in 2 ml of 2,2,2-trifluoroethanol, 2-(2-chloro-1
, 3,4-thiadiazol-5-yloxy)-acetopiperidide was added at -20°C. After returning to room temperature, the mixture was stirred for 24 hours. The solvent was distilled off under reduced pressure, water was added, and the mixture was extracted with 20 ml of dichloromethane. After drying the extract over anhydrous sodium sulfate, dichloromethane was distilled off under reduced pressure. The residue was purified by silica gel chromatography (dichloromethane and dichloromethane/methanol) to give 2-(2-2,2,2-trifluoroethoxy-1,
0.68 g (yield: 42%) of 3,4-thiadiazol-5-yloxy)-acetopiperidide was obtained.

Example 3 N-methyl-2-(2-2,2,3,3,4,4,4-
Production of n-heptafluorobutoxy-1,3,4-thiadiazol-5-yloxy)-acetanilide 2,2
, 3,3,4,4,4-N-Heptafluorobutanol 0.06g was dissolved in 2ml of N-heptafluorobutanol.
0.4 g of methyl-2-(2-chloro-1,3,4-thiadiazol-5-yloxy)-acetanilide was added at room temperature and stirred for 2 days. The solvent was distilled off under reduced pressure, water was added, and the mixture was extracted with 20 ml of toluene. The extract was washed twice with water and then dried over anhydrous magnesium sulfate.

After distilling off toluene under reduced pressure, the residue was purified by silica gel chromatography (toluene and chloroform) to obtain N-methyl-2-(2-2,2,3,3,
4,4,4-n-heptafluorobutoxy-1,3,4
-thiadiazol-5-yloxy)-acetanilide 0.28 g (yield 44%) was obtained.

Examples 4 to 29 The following compounds were prepared in the same manner as in Examples 1 to 3, and the physical properties pmr of these compounds are shown together with the physical properties pmr of the compounds of Examples 1 to 3.

[0034]

[Table 1]

[0035]

[Table 2]

[0036]

[Table 3]

In Tables 1, 2 and 3, R2 and R
When one heterocyclic group is described in column 3, it is the case that R2 and R3 together with the nitrogen atom to which they are bonded form a heterocyclic group.

[0038]

[Formulation Example] Next, a formulation example will be shown, and the compound (I) of the present invention incorporated therein is applicable to all of the compounds of Examples 1 to 29. In addition, all parts in the formulation examples mean parts by weight.

Formulation Example 1 10 parts of the compound (I) of the present invention, 1 part of naphthalene sulfonic acid formalin condensate, 0.5 part of polyoxyethylene alkylphenol ether, 0.5 part of white carbon and 88 parts of calcined diatomaceous earth were thoroughly ground and mixed. A wettable powder was obtained.

Formulation Example 2 20 parts of the compound (I) of the present invention, 20 parts of white carbon,
A wettable powder was obtained by uniformly mixing 3 parts of calcium lignin sulfonate, 2 parts of polyoxyethylene nonylphenyl ether, and 55 parts of clay using a grinding mixer.

Formulation Example 3 An emulsion was obtained by mixing and dissolving 20 parts of the compound (I) of the present invention, 15 parts of Sorbol 700HD emulsifier (manufactured by Toho Chemical Industries, Ltd.), 20 parts of cyclohexanone, and 45 parts of xylene.

Formulation Example 4 3 parts of the compound (I) of the present invention, 1 part of lauryl sulfate,
2 parts calcium lignin sulfonate, 30 parts bentonite
After adding 15 parts of water to 64 parts of clay and kneading with a kneader, granules were granulated with a granulator and dried with a fluidized fluidized dryer to obtain granules.

[0043]

[Test Examples] Test examples are shown below to clarify the usefulness of the compound (I) of the present invention as a herbicide.

Test Example 1: Paddy field herbicidal activity test A 300g OPS seedling pack (13 x 9 x 5 cm) was filled with paddy soil.
After flooding to create a paddy field, rice seedlings at the 2.5 leaf stage were transplanted.

[0045] Further, wild grass, firefly, Japanese cypress, Japanese cypress, and staghorn grass were sown.

[0046] The day after rice transplantation (1 day after weed sowing: before emergence)
A predetermined dose of the test compound was diluted with 5 ml of water per pot and dropped onto the water surface of the pot using a pipette. After treatment,
The plants were kept in a greenhouse for 3 weeks, and the herbicidal effect and degree of chemical damage were investigated and evaluated according to the following criteria.

(Evaluation method) The results are shown in Table 4: 5: Complete withering, 4: Severe damage, 3: Medium damage, 2: Slight damage, 1: Slight damage, 0: No harm.

[0048]

[Table 4]

Test Example 2: Field field herbicidal activity test Pre-emergence treatment Field soil was packed into a 300 g pack of OPS seedlings, and weeds such as crabgrass, sycamore, chickweed, and dogweed were sown and covered with soil.

[0050] Immediately thereafter, a predetermined amount of the test compound was diluted in 30 liters of water per are and uniformly sprayed on the soil surface using a chromatographic glass spray. Thereafter, the treatment was carried out in a glass greenhouse, and three weeks after the treatment, the herbicidal effect on each weed was investigated and evaluated according to the following criteria.

(Evaluation method) The results are shown in Table 5: 5: Complete withering, 4: Severe damage, 3: Medium damage, 2: Slight damage, 1: Slight damage, 0: No harm.

[0052]

[Table 5]

[0053]

Effects of the Invention The compound (I) of the present invention has excellent properties such as herbicidal activity against various plants and herbicidal selectivity. In addition, the compound (I) of the present invention has extremely low toxicity to humans, livestock, poultry, etc., and low toxicity to fish, so it has excellent safety.
There is no problem with residual toxicity. Therefore, it can be applied as a herbicide to a wide range of useful crops.

Claims (3)

[Claims] Claim 1: General formula (I) [Formula 1] (wherein, R1 represents fluorine-substituted alkyl, R2 represents lower alkyl or lower alkenyl, R3 represents optionally substituted phenyl, or R2 and R3
together with the nitrogen atom to which they are attached represent a heterocyclic group. ) A 1,3,4-thiadiazole derivative represented by Claim 2: General formula (II) [Formula 2] (wherein, R2 is lower alkyl or lower alkenyl, R3 is optionally substituted phenyl, or R2
and R3 together with the nitrogen atom to which they are bonded represent a heterocyclic group. X represents a halogen atom. ) and a compound represented by the general formula (III) R1 OH (III) (wherein R1 represents a fluorine-substituted alkyl) or a reactive derivative thereof. I) [Formula 3] (wherein, R1 represents a fluorine-substituted alkyl, R2 represents a lower alkyl or lower alkenyl, R3 represents an optionally substituted phenyl, or R2 and R3 represent a bond thereof. A method for producing a 1,3,4-thiadiazole derivative represented by: Claim 3: General formula (I): (wherein, R1 represents fluorine-substituted alkyl, R2 represents lower alkyl or lower alkenyl, R3 represents optionally substituted phenyl, or R2 and R3 together with the nitrogen atom to which they are bonded represent a heterocyclic group.