JPS6163668A - Selective herbicide - Google Patents

Abstract

NEW MATERIAL:5-{1-[4-(4-Cyanophenoxy)phenoxy]-ethyl}-1,2,4-oxadiazole of formula I. USE:A herbicide having remarkable intergenus selectivity, having no phytotoxicity to transplanted paddy rice plant or rice plant sowed directly to paddy field, and exhibiting excellent herbicidal effect against cockspur-grass which is a harmful weed in paddy field. The durability of the activity is remarkable, and the herbicidal activity is almost independent of the kind of soil. PREPARATION:The compound of formula I can be prepared by condensing the compound of formula II (X is halogen) with the compound of formula III in a solvent such as hydrocarbon, ether, etc., in the presence of a dehydrohalogenation agent such as tert-amine, inorganic base, etc. at 0-50 deg.C, and heating and cyclizing the condensation product in a proper solvent at 70-130 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a 5-ethyl-/rader oxadiazole derivative and a herbicide characterized by containing the compound as an active ingredient.

[Conventional technology]

Conventionally, 5-ethyl-7, ladder oxadiazole derivatives having herbicidal activity include 5--[4-CF-(-1-R-R--trifluoromethylphenoxy)phenoxyphethyl)-/, 2. F-oxanoazole (Unexamined Japanese Patent Publication No. 717), 5-[4-[Hiro-(S
-trifluoromethyl-copyrisoloxy)phenoxyphethyl)-/,,1? , Hiro-Oquinacyazole (
Tokukai Showa 5g-1g36gg, 5g-2100tO, 5?
-9g0g:, Publication No. 3)5;-[4-Cg-(,2,
! -zochlorophenoxy)phenoxyphethyl)-/,
Je-oxazoazole (%Kasho 5g-co 1007J publication) and the like are known.

[Problem that the invention seeks to solve]

In rice cultivation, it exhibits a strong herbicidal effect against the harmful weed, especially weeds, when applied to the surface of the water, and has no effect on rice at any stage from direct sowing to transplanting. The market demand for herbicides that exhibit high interwing selectivity remains strong even now, even though many herbicides have already been developed and are on the market.The purpose of the present invention is to meet the market demand. Our goal is to provide the best herbicide.

[Means for solving problems]

Non-invention is 5-[4-C goo (ll-cyanophenoΦshi)
The present invention provides a herbicide characterized by containing the compound of the present invention as an active ingredient, and the compound of the present invention as an active ingredient. Herbicides as active ingredients are
It has the characteristics of not causing any chemical damage to transplanted paddy rice or directly sown paddy rice in flooded rice fields, and exhibits an excellent herbicidal effect against grasshopper, which is a harmful weed in paddy fields. The compound of the present invention is a new compound that has not been described in any literature.

[Effect]

The compound of the present invention can be produced by various methods, but
A typical manufacturing method is shown in the reaction formula below.

(In the formula, X represents a halide atom.) In the reaction formula (L), the condensation reaction (A is usually 0
The reaction takes place at a reaction temperature of ˜50° C. and a reaction time of 7 hours to 7 hours.

As the dehydrohalogenating agent, tertiary amines such as triethylamine, bilysin, and dimethylaniline, and inorganic bases such as potassium carbonate and sodium carbonate can be used.

As a reaction solvent, hydrocarbon water A field such as hexane, benzene, toluene, diethyl ether, tetrahydrofuran,
Ethers such as dioxane, ketones such as acetone, methyl ethyl ketone, #JP tetrachloride, base, chloroform,
Examples include halogenated hydrocarbons d' such as methine chloride/dichloroethane.

The ring-closing reaction in Reaction Formula (D) (a can be carried out by heating in a suitable solvent such as benzene, toluene, xylene, etc. at a reaction temperature of 70 to 3θ°C for a reaction time of 30 minutes to 10 hours. .

- 10,000, the following reaction is shown in reaction formula (n), using a suitable solvent, such as hydrocarbons such as hexane, benzene, toluene, xylene, ketones such as acetone, methyl ethyl ketone, etc.
Ethyl acetate, acetonitrile, zomethylformazde,
In a solvent such as dimethyl sulfoxide, in the presence of a suitable dehydrohalogenating agent, such as a tertiary amine such as triethylamine, bilysin, or dimethylaniline, or an inorganic base such as potassium carbonate or sodium carbonate, the reaction temperature is 4tθ to /2θ°C.
(by heating for a reaction time of 7 to 10 hours).

Traditionally, weeding of Noviae, which is an important weed in paddy fields, takes advantage of the difference in chestnut chemical resistance due to the difference in the growing period of Noviae and paddy rice, and controls only the Noviae at the time of germination without harming the paddy rice that has advanced in growth. Alternatively, it is said that the treatment agent is adsorbed to the topsoil of the soil and inhibits the germination of Noviea seeds located within the chemical layer, and paddy rice roots located outside the chemical adsorption layer are not affected. Weeding has been carried out by physical selection method. Therefore, it has been extremely difficult to apply these herbicides to directly sown rice in warm water or to inoculum immediately after transplantation.

In order to provide a herbicide that is safe even for weak rice such as direct-seeded rice, the present inventors conducted a search for a compound that has a physiological selective activity specific to the drug between paddy rice and wild grass. Remarkable interwing selectivity 7j - It is placed on the armpits, gives almost no shade q1 to paddy rice, and exhibits a strong herbicidal effect on wildflowers.
It has been discovered that its effectiveness is extremely consistent and its effectiveness does not change much depending on soil type 81, so it can be applied to a wide range of fields, from direct sowing to transplanted rice.

The amount of the compound of the present invention to be applied varies depending on the application situation, application period, and application method, but generally the amount of the active ingredient is 0.0/
l ~ 100 t/a, preferably i! 0.
A range of /f to tj;09/a is appropriate.

In order to use the compound of the present invention as a herbicide, each
For example, it is used by blending a diluent, a solvent, a surfactant, etc. into the form of an emulsion, an aqueous solution, a powder, a granule, or the like.

The herbicide of the present invention can be applied in combination with other agricultural chemicals used in the same field, such as insecticides, fungicides, herbicides, plant growth regulators or fertilizers. In particular, it may be appropriate to add and mix the following herbicides for the purpose of reducing spraying labor or expanding the range of grass species that can be effectively controlled.

4tI-dichlorophenoxyacetic acid, its salts, esters and alkylamine salts = -methyl-dichlorophenoxyacetic acid, its salts and esters methyl-Hiro-chlorophenoxyacetic acid, its salts and esters <1-2-(4 -chloro-0-)zyloxy)propionic acid, its salts and esters octanoic acid-gucyano 46-zoiodophene 4'l
-zo/lorophenyl luc'-nitro 2 enyl ether, 2'A Is -'P li/ o o phenyl-hiro'-nitrophenyl ether ladder dichlorophenyl-3'-methoxy-hiro'-nitrophenyl ether, 7. ! -Sochlorocarpanilide relative methyl 3-chlorocarpanilide isoglobylnoethylthiolpξdom-5-p-chloropendylgoonitrophenyl-,27s'-Φsilyl ether hexahydro-/ H-Azepine-/-Calgithioic acid-5-
Ethyl J,'l-no/loroglobionanilito-chloro-4
'6'-Diethyl-N-(butoxymethyl)acetanilide λ-chloro,,! , 'A'-noethyl-N-(m-
propoxyethyl)acetanilide/-(qα-dimethylpencyl)-J-p-1 lylurea 2+-bis(ethylamino)~6-methylthio/,
J,! ;-triala2-isopropylamino-6-methylthio-/
, J,! Neelianon Yohiro-bis(inpropylamino-6-methylthio-/, 3.!; Neelianon S-tart-buty#-J-(-2,Q-jiguoo-
3-Ingropoquinphenyl I-/, 3. tl-oxanoazolin-2-one di6-dichlorobenzonitrile; 4b-J/ychlorotimebenzagbee-amino-3
-chloro-/, 4t-naphthotinone, 2. Turfchlorophenyl-3'-ru? Methoxida'-Nitrophenyl ether N-1)-Chloropencyloxyphel-4-46-
Titrahydrophthalimidoterdichlorophenyl-31-ethoxyethoxy-+
'-nido r:I phenyl ether N-[4-ethylglobil)-6-zonitro-3, guxylinone F-(,21I-nochloropenzoyl)-/, 7-zomethyl-pi2zol-5+yl-p-toluene Sulfonate goo (zig-dichlorobenzoyl)-/, 3-methyl-5-(benzoylmethoxy)-hyrazol goo (shihiro-dichloro-3-methylbenzoyl)-/1
3-dimethyl-3-(benzoylmethoxy)pyrazole o,o-y inpropyluco(benzenesulfonoabad)-ethylenenotio7-ophosphate 3. Dipenzophenone α-(2-sulphate) in 3'-tsumethyl-hiro-meth 7toxy)-propionanilide 0-ethyl-〇-(3-methyl-6-nitrophenyl)-N-sec-butylphosphorothioamidate 3-inpropyl-243-pen! Chianoasonone (
4Q-42-dioxide and 70-3-(neemethyl-
/~rubiperitrucarnylmethyl)-QO-so n-
De0gyl dithiophosphate S-benzyl-N,N-methylthiocarbamate [Example] Next, the method for producing the compound of the present invention will be specifically explained in Example f. The method is not limited to this example only.

Example / 2/3? Knee [Hiro-(l/l-cyanophenoxy)
Phenoxy]globionyl chloride" + 1-50 m of sochloromethane/C solution layer, ag 5f of formamide oxy/mt-/θ°C or less under stirring under cooling, then add 0 to 5 Q 7; l 9 of triethylamine was added dropwise over 5 minutes at 100°C. After the dropwise addition, the reaction mixture was stirred for 6 hours with a concentrated solution and washed with water. 7 obtained by boiling the thick sardines was dissolved in toluene to form a light brown oily residue,
The mixture was stirred at high speed for 3 hours. Reaction a was cooled to room temperature and washed with water. The toluene layer dried over anhydrous magnesium sulfate was evaporated under pressure, and the resulting oily residue was purified by silica gel chromatography to obtain 5-(nee [t
-(Hiro-cyanophenoxy)phenoxy]ethyl)-/
, 2≠-oxadiazole was obtained in 6 st. Yield 3
0% nmr, (CDCI?,) /, 73 ppm (JH, (1), 5.52p
pm [4H,q)7, /3 ppm (&H,m)
, gjppm [4RS) Next, examples of specific formulations using the compounds of the present invention will be described.

Example = Emulsion 20 parts of the compound of the present invention, 25 parts of xylene 73s1 polyoxyethylene alkyl ether (parts are based on TL Sumirebe, the same applies hereinafter), ? Rioki 7 Ethylenoalkyl Azyl Ether/, jm, Calcium alkylbenzenesulfonate 3flSt - Uniformly dissolve to form an emulsion.

Example 3 Granules The compound of the present invention was mixed and pulverized with 5s1 White Cargon 2VA, and bentonite=co part, talc=yuyo part,
26 parts of clay, 2 m of sodium lignin sulfonate, and 0.5 part of sodium dodecylbenzenesulfonate are uniformly mixed, water is added, the mixture is granulated using an extrusion granulator, and the mixture is dried and sieved to obtain granules.

Next, the herbicidal effects of the compounds of the present invention will be explained using Examples.

Effectiveness test against nobies! After paddy soil was filled in a 000 min/Ahl Wagner pot and paddy soil was raked, 50 Novie seeds were sown. Flooding method 3I: Maintain MK, and when the wildflower seeds germinate and/or reach the Ss stage, make the compound of the present invention into an emulsion according to Example Ω, dilute the specified leaves with water, and apply each to the water surface uniformly. did.

After 75 days of chemical treatment, a survey was conducted on the herbicidal effect and efficacy of the herbicide, and the results shown in Tables 1 and 2 were obtained.

The weed killing effect of No. 7 was evaluated based on the following criteria.

Number of evaluations Weed killing effect ! Completely withered Da za 0-9? − suppression 3 60-79 I Yu Hiro 0-691! suppression of / 20-39 No IO suppression The values in Table 1 indicate the ratio of live weight to the untreated area.

Table 1 - Thorns [Effects of the Invention] As is clear from Tables 1 and 2, the compound of the present invention shows no phytotoxicity at all in both the flooded and directly sown paddy rice during germination and in the ≠O9/a treatment. do not have. In addition, the germination period and/or S
It can effectively control wild grass in the leaf stage.

The compound of the present invention can be used as a highly selective herbicide without phytotoxicity in flooded direct seeded rice cultivation, or tMt water transplanted rice cultivation, and has very high utility value.

As described above, the compound of the present invention has many fc characteristics as a herbicide and is highly practical.

Claims (2)

[Claims] (1) 5-{1-[4-(4-cyanophenoxy)phenoxy]-ethyl}-1,2,4-oxadiazole. (2) A selective herbicide characterized by containing 5-{1-[4-(4-cyanophenoxy)phenoxy]-ethyl}-1,2,4-oxadiazole as an active ingredient.