GB2194534A - Triazolone herbicides - Google Patents

Abstract

Compounds of the formula I <IMAGE> wherein R<1> is hydrogen or an alkyl group containing 1 to 4 carbon atoms; R<2> is halogen of atomic number 9 to 35, or a group (X)mR<3> in which X is oxygen, sulfur, sulfinyl or sulfonyl; R<3> is an alkyl group containing 1 to 4 carbon atoms optionally substituted by one or more halogen atoms of atomic number 9 to 35; m is 0 or 1; and n is 1 to 3, are useful as herbicides.

Description

SPECIFICATION Triazolone herbicides The present invention relates to new 4-(benzylamino)-2,4-dihydro-3H- 1 ,2,4-triazol-3-ones, their use as herbicides and to herbicidal compositions containing these compounds.

U.S. patent 3,884,910 discloses certain 4-benzylideneamino-A2-1,4-triazolin-5-ones useful as herbicides. However, there is still a need to improve the level of activity found in such compounds.

The present invention provdes structurally different herbicides that demonstrate good activity, particularly against troublesome broadleaf weeds in pre-emergence application.

The present invention is directed to compounds of the formula I

wherein R' is hydrogen or an alkyl group containing 1 to 4 carbon atoms; R2 is halogen of atomic number 9 to 35, or a group (X)mR3 in which X is oxygen, sulfur, sulfinyl or sulfonyl; R3 is an alkyl group containing 1 to 4 carbon atoms optionally substituted by one or more halogen atoms of atomic number 9 to 35; m is O to 1; and n is 1 to 3.

Representative novel compounds of formula I of the present invention include those compounds wherein R' is hydrogen, alkyl, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobu tyl, sec-butyl and tertiary butyl; R2 is hydrogen, halogen, such as fluorine, chlorine or bromine, or (X)mR3 such as methyl, ethyl, isopropyl, tertiary butyl, methoxy, ethoxy, isopropoxy, chloromethyl, trichloromethyl, trichloromethoxy, difluoromethoxy, trifluoromethyl, trifluoromethoxy, 1,2-dibromoethyl and the like as well as the corresponding compounds where m is 1 and X is sulfur, sulfinyl or sulfonyl.

Non-limiting illustrative embodiments of species within the scope of the present invention include 4((3-(difluoromethoxy)benzyl)amino)-2,4-dihydro-3H-i ,2,4-triazol-3-one, 4-((3-chloro-4-fluoro)benzyl)amino)-2,4-dihydro-3H- 1 ,2,4-triazolin-3-one, 4-((3-(trifluoromethyl)benzyl)amino)-2,4-dihydro-3H-1,2,4-triazolin-3-one) and the like.

In one preferred form of the invention, R1 is hydrogen. In another preferred form of the invention, R2n is XmR3 in which X is oxygen, R3 is methyl optionally substituted by one or more fluorine atoms, m is O to 1 and n is 1. In a further preferred form, R2n is 3-trifluoromethyl or 3trifluoromethoxy.

The compounds of formula I of the invention may be prepared by reducing the corresponding 4-(benzylideneamino)-2,4-dihydro-3H-1,2,4-triazol-3-ones disclosed in the U.S. patent 3,884,910 in the presence of a suitable reducing agent, such as sodium borohydride and the like. The reduction is conducted under anhydrous conditions, preferably in the presence of solvent such as methanol, ethanol and the like. The reduction proceeds with good yields and the products are recoverd by conventional techniques of, e.g. filtration, chromatography, crystallization, precipitation, solvent extraction and the like.

For application, a compound of formula I ordinarily is applied most effectively by formulating it with a suitable inert carrier or surface-active agent, or both. The invention, therefore, also includes compositions suitable for combatting unwanted plants, such compositions comprising an inert carrier or surface-active agent, or both, and as active inredient at least one compound of formula The term "carrier" as used herein means an inert solid or liquid material, which may be inorganic or organic and of synthetic or natural origin, with which the active compound is mixed or formulated to facilitate its application to the plant, seed, soil or other object to be treated, or its storage, transport and/or handling.Any of the materials customarily employed in formulating pesticides, herbicides, or fungicides-i.e., horticulturally acceptable carriers-are suitable.

Suitable solid carriers include natural and synthetic clays and silicates, for example natural silicas such as diatomaceous earths; magnesium silicates, for example talcs; magnesium aluminium silicates, for example attapulgites and vermiculites; aluminium silicates, for example kaolinites, montmorillonites and micas; calcium carbonate; calcium sulphate; synthetic hydrated silicon oxides and synthetic calcium or aluminium silicates; elements such as, for example, carbon and sulphur; natural and synthetic resins such as, for example, coumarone resins, polyvinyl chloride, and styrene polymers and copolymers; bitumen; waxes such as, for example, beeswax, paraffin wax, and chlorinated mineral waxes; solid fertilizers, for example, superphosphates; and ground, naturally-occurring, fibrous materials, such as ground corncobs.

Example of suitable liquid carriers are water, alcohols such as isopropyl alcohol and glycols; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ethers such as cellosolves; aromatic hydrocarbons such as benzene, toluene and xylene; petroleum fractions such as kerosene and light mineral oils; chlorinated hydrocarbons such as carbon tetrachloride, perchloroethylene and trichloromethane. Also suitable are liquefied, normally vaporous and gaseous compounds. Mixtures of different liquids are often suitable.

The surface-active agent may be an emulsifying agent or a dispersing agent or a wetting agent; it may be nonionic or ionic. Any of the surface-active agents usually applied in formulating herbicides or insecticides may be used. Examples of suitable surface-active agents are the sodium and calcium salts of polyacrylic acids and lignin sulfonic acids; the condensation products of fatty acids or aliphatic amines or amides containing at least 12 carbon atoms in the molecule with ethylene oxide and/or propylene oxide; fatty acid esters of glycerol, sorbitan, sucrose or pentaerythritol; condensates of these with ethylene oxide and/or propylene oxide; condensation products of fatty alcohols or alkyl phenols, for example, p-octylphenol or p-octylcresol, with ethylene oxide and/or propylene oxide; sulfates or sulfonates of these condensation products, alkali or alkaline earth metal salts, preferably sodium salts, of sulfuric or sulfonic acid esters containing at least 10 carbon atoms in the molecule, for example, sodium lauryl sulfate, sodium secondary alkyl sulfates, sodium salts of sulfonated castor oil, and sodium alkylaryl sulfonates such as sodium dodecylbenzene sulfonate; and polymers of ethylene oxide and copolymers of ethylene oxide and propylene oxides.

The compositions of the invention may be prepared as wettable powders, dusts, granules, solutions, emulsifiable concentrates, emulsions, suspension concentrates and aerosols. Wettable powders are usually compounded to contain 25 to 75% by weight of active compound and usually contain, in addition to the solid carrier, 3-10% by weight of a dispersing agent, 2-15% of a surface-active agent and, where necessary, 0-10% by weight of stabilizer(s) and/or other additives such as penetrants or stickers. Dusts are usually formulated as a dust concentrate having a similar composition to that of a wettable powder but without a dispersant or surfaceactive agent, and are diluted in the field with further solid carrier to give a composition usually containing 0.5-10% by weight of the active compound.Granules are usually prepared to have a size between 10 and 100 BS mesh (1.676-0.152 mm), and may be manufactured by agglomeration or impregnation techniques. Generally, granules will contain 0.5-25% by weight of the active compound, 0-1% by weight of additives such as stabilizers, slow release modifiers and binding agents. Emulsifiable concentrates usually contain, in addition to the solvent and, when necessary, cosolvent, 10-50% weight per volume of the active compound, 2-20% weight per volume emulsifiers and 0-20% weight per volume of appropriate additives such as stabilizers, penetrants and corrosion inhibitors.Suspension concentrates are compounded so as to obtain a stable, non-sedimenting, flowable product and usually contain 10-75% weight of the active compound, 0.5-5% weight of dispersing agents, 1-5% of surface-active agent, 0.1-10% weight of suspending agents, such as defoamers, corrosion inhibitors, stabilizers, penetrants and stickers, and as carrier, water or an organic liquid in which the active compound is substantially insoluble; certain organic solids or inorganic salts may be dissolved in the carrier to assist in preventing sedimentation or as antifreeze agents for water.

Of particular interest in current practice are water-dispersible granular formulations. There are in the form of dry, hard granules that are essentially dust-free, and are resistant to attrition on handling, thus minimizing the formation of dust. On contact with water, the granules readily disintegrate to form stable suspensions of the particles of active material. Such formulations contain 90% or (up to 9596) more by weight of finely divided active material, 3-7% by weight of a blend of surfactants, which act as wetting, dispersing, suspending and binding agents, and may contain up to 3% by -weight-of a finely divided carrier, which acts as a resuspending agent.

Aqueous dispersions and emulsions, for example, compositions obtained by diluting a wettable powder or a concentrate according to the invention with water, also lie within the scope of the present invention.The said emulsions may be of the water-in oil or of the oil-in-water type, and may have thick, mayonnaise-like consistency.

It is evident from the foregoing that this invention contemplates compositions containing as little as about 0.5% by weight to as much as about 95% by weight of a compound of Formula I as the active ingredient.

The compositions of the invention may also contain other ingredients, for example, other compounds possessing pesticidal, especially insecticidal, acaricidal, herbicidal or fungicidal properties, as are appropriate to the intended purpose.

Protection of a locus or area from undesirable plants is effected by applying a compound of formula I, ordinarily in a composition of one of the aforementioned types, to soil in which the seeds of the unwanted plants are present, or to the foliage of the unwanted plants, particularly broadleaf weeds in pre-emergence application. The active compound, of course, is applied in an amount sufficient to exert the desired action.

The amount of the comound of the invention to be used in combatting undesired plants will naturally depend on the condition of the plants, the degree of activity desired, the formulation used, the mode of application, the climate, the season of the year, and other variables. Recommendations as to precise amounts are, therefore, not possible. In general, however, application to the locus to be protected of from 0.1 to 10.0 kg per hectare of the compound of formula I will be satisfactory.

The present invention is illustrated by the following examples which are presented for the purpose of illustration and should not be regarded as limiting the invention in any way. The identity of the products was confirmed by elemental infrared and nuclear magnetic resonance spectral (NMR) analysis as necessary.

Example 1 4-((3-(trifluoromethyl)benzyl)amino)-2,4-dihydro-3H- 1 ,2,4-triazol-3-one To a solution stirred at room temperature of 2.0 g of 4-((3-(trifluoromethyl)benzylidene)amino) 2,4-dihydro-3H-1 ,2,4-triazol-3-one in 40 ml of anhydrous methanol was added dropwise a solution of 0.59 g of sodium borohydride, NaBH4, in 20 ml of methanol. After the addition was complete, the solution was heated at reflux for 15 minutes, then poured into 100 ml of icewater. The resulting precipitate was collected by filtration and dried under vacuum to give 1.5 g of the desired product as a white solid, m.p.: 157-159"C.

Example 2 4-(3-)trifluoromethoxy)benzyl)amino)-2,4-dihydro-3H- 1 ,2,4-triazol-3-one To a solution stirred at room temperature of 1.89 of 4-((3-trifluoromethyl)benzyl)amino-2,4dihydro-3H-1,2,4-triazol-3-one in 40 ml of methanol was added dropwise a solution of 0.05 g of sodium borohydride (NaBH4) in 20 mi of methanol. After the addition was complete, the solution was heated to reflux for 15 minutes, then poured into 100 ml of ice-water. The resulting precipitate was collected by suction-filtration and dried to give 1.4 g of the desired product as a while solid, m.p.: 135-138"C.

Examples 3-1 1 Following procedures analogous to those described in Examples 1 and 2 above, the following additional compounds in accordance with the invention are prepared as set forth in Table 1 below.

Table 1

Example R Rn 3 CH3 2,4-Cl2 4 C2H5 3-CF3 5 H 4-Cl 6 H 3-CH3,4-Br 7 H 3-C1,4-CH3 8 H 3-OCF3 9 H 2-Cl 10 H 2,6-Cl2 11 H 3,4-Cl2 12 H 3-CH3 13 H 3-OCHF2 Example 12 Herbicidal Activity The species of plants that were tested were: Abbreviation Barnyardgrass (watergrass)-Echinochioa crus-galli BYGR Downy brome-Bromus tectorum DOBR Yellow foxtail-Setaria glauca YEFT Sicklepod-Cassia obtusifolia SIPO Velvetleaf-Abutilon . theophrasti VELE Garden cress-Lepidium sativum GACR Johnsongrass-Sorghum halepense JOGR Morningglory-lpomoea sp. MOGL Nightshade-Solanum sp.NISH Blackgrass-Alopecurus myosuroides BLGR Yellow millet-Panicum milceum YEMI Large cra bg rass-Digitaria sanguinalis LACG Redroot pigweed-Amaranthus retroflexus RRPW Hemp sesbania-Sesbania exaltata HESE Prickly sida-Sida spinosa PRSI Wild oats-Avena fatua WIOA Cocklebur-Xanthum strumarium COCB Annual ryegrass-Lolium multi forum ANRG Giant foxtail-Setaria faberi GIFT Texas panicum-Panicum texanum TEPA Common Lambsquarters-Chenopodium album LAQU Test Procedures The preemergence (soil) herbicidal activity of compounds of Formula I was evaluated by planting seeds of downy brome, johnsongrass, yellow foxtail, barnyardgrass, yellow millet, black grass, hemp sesbania, velvetleaf, morningglory, prickly sida, sicklepod and garden cress in test tubes, nominally measuring 25 x 200 millimeters, filled about three-quarters full of untreated soil, in each case covered on top with about 2.5 cubic centimeters of soil treated with 0.1 milligram of the test compound, to give a dosage of 2.24 kg of test compound per hectare (2.0 pounds per acre). The seeds were planted on top of the treated soil and covered with about 1.5 cubic centimetres of untreated soil. The planted soil was held under a controlled regimen of temperature, moisture, and light.At 10 days, the amounts of germination and growth in each tube were evaluated on a O to 9 scale, the numeric ratings having the following meanings: Rating Meaning 9 No living tissue 8 Plant severely damaged and expected to die 7 Plant badly damaged, but expected to live 6 Moderate damage, but complete recovery expected 5 Intermediate damage (probably unacceptable for crop plants) 3-4 Observable damage 1-2 Plant slightly affected, possibly by the chemical, possibly due to biological variability O No visible effect Results of the preemergence herbicidal activity tests are set forth in Table I.

TABLE I. PREEMERGENCE HERBICIDAL ACTIVITY Compound of Example No. DOBR JOGR YEFT BYGR YEMI BLGR HESE VELE NOGL PRSI SIPO GACR 1 3 7 0 6 3 5 7 0 6 5 7 5 2 0 4 0 5 3 5 8 0 7 6 7 4 Examples of Selectivity The preemergence activity of compounds of formula I was further determined with respect to certain species of common weeds, by spraying a formulation of the test compound on soil in small pots in which seeds of the plants had been sown. In each series of tests, the plants were grown in pots placed in narrow trays and sprayed with the formulation. The results of the tests were evaluated on the basis of the 0-9 scale described with respect to the earlier tests. The results of the tests are reported in Table II.

TABLE II. PREEMERGENCE HERBICIDAL ACTIVITY Compound of Rate Grass Weeds Example No. (lb/A) BYGR DOBR JOGR WIOA YEFT TERA GIFT ANRG COCB MOGL BRPW SIPO VELE NISH HESS PRSI LAQU 2 4.0 7B 6 8B 8 7B 8 9 9 7B 9 9 9 8 9 9 9 9 1.0 9 4 8B 6 5B 4 4 6 2 7 9 9 5 9 9 9 9 1 4.0 9 7B 9 9 4B 8 6B 9 7 9 9 9 7B 9 9 9 9 1.0 8 9 8 7 1B 6B 2B 8 3B 5B 9 9 2B 9 8 7 9 B"means" bleaching

Claims (8)

1. A compound of the formula I

wherein R1 is hydrogen or an alkyl group containing 1 to 4 carbon atoms; R2 is halogen of atomic number 9 to 35 or a group (X)mR3 in which X is oxygen, sulfur, sulfinyl or sulfonyl; R3 is an alkyl group containing 1 to 4 carbon atoms optionally substituted by one or more halogen atoms of atomic number 9 to 35; m is O or 1; and n is 1 to 3.

2. A compound according to claim 1 wherein R' is hydrogen.

3. A compound according to claim 1 or 2 wherein R2n is XmR3 in which X is oxygen, R3 is methyl optionally substituted by one or more fluorine atoms, m is O to 1 and n is 1.

4. A compound according to claim 3 wherein R2n is 3-trifluoromethyl.

5. A comound according to claim 3 wherein R2n is 3-trifluoromethoxy.

6. A compound of formula I as defined in claim 1 substantially as described herein with reference to any one of Examples 1 to 13.

7. A herbicidal composition which comprises a herbicidally effective amount of a compound according to any one of the preceding claims and at least one surface-active agent and/or carrier.

8. A method for combatting unwanted plant growth at a locus comprises applying to the locus a herbicidally effective amount of a compound according to any one of claims 1 to 6 or a composition according to claim 7.