GB2170500A - N-(3-substituted-4-isopropylphenyl)-2-methyl-2-pentenamide derivative and selective herbicide - Google Patents

Abstract

A compound of formula <IMAGE> wherein Y is Cl, F or CH3 is provided as a useful selective herbicide. This compound can be produced by reacting an aniline of general formula <IMAGE> wherein Y is as defined, with a 2-methyl-2-pentenoic acid derivative of formula <IMAGE> wherein X is a halogen, or with 2-methyl-2-pentenoic acid anhydride.

Description

SPECIFICATION N-(3-substituted-4-isopropylphenyl)-2-methyl-2-pentenamide derivative and selective herbicide This invention relates to an N-(3-substituted-4-isopropylphenyl)-2-methyl-2-pentenamide derivative, and a selective herbicide comprising it as an active ingredient which controls noxious weeds in the cultivation of wheat, an important gramineous crop in agriculture, effectively and selectively by foliar application.

For a control of weeds in wheat cultivation, phenoxy-type herbicides have been used most widely.

They include, for example, 2,4-dichlorophenoxyacetic acid [2,4-D; P. W. Zimmerman and A. E. Hitchcock, Contrib. Boyce Thompson Inst., 12, 321(1942)], 2-methyl-4-chlorophenoxy-acetic acid [MCPA; M. E. Synerholm and P. W. Zimmerman, Contrib. Boyce Thompson Inst., 14, 91(1945)], 4-(2-methyl-4-chlorophenoxy)butyric acid [MCPB; German Patent 1,000,632 (1957) and British Patent 793,513 (1958)], and 4-(2,4dichlorophenoxybutyric acid [2,4-DB; M. E. Synerholm and. P. W. Zimmerman, Contrib. Boyce Thompson Inst., 14, 369 (1945)]. However, these herbicides are foliar treating agents which are effective only for controlling broad-leaved weeds, and because of their significant phytotoxicity to wheat, their use is limited only to a stage where the crop has grown to some extent.

Urea-type herbicides such as 3-(3,4-dichloro-phenyl)-1 -methoxy-1 -methyl urea [linuron; U. S. Patent 2,960,534 issued November 15, 1960], 3-(3-chloro-4-methoxy-phenyl)-1,1-dimethylurea [metoxuron; French Patents 1,497,867 and 1,497,868 granted October 13, 1967], 3-(3-chloro-4-methylophenyl)-1,1-dimethylurea [chlortoluron; U. S. Patents 2,655,444 and 2,655,445 issued October 13, 1953], 3-(4-isopropylphenyl)-1,1-dimethylurea [isoproturon; German OLS 2,107,774 published September 16, 1971, and German OLS 2,137,992 published February 10, 1972], and 3-(2-benzothiazolyl)-1,3-dimethylurea [methabenzthiazuron; U. S. Patent 2,756,135 issued July 24, 1956 and British Patent 1,085,430 patented October 4, 1967] are very important in wheat cultivation.Since, however, most of them cause phytotoxicity to the crop, they are used mainly as a preemergence soil treating agent. When they are used as a foliar treating agent, their selectivity differs greatly depending upon the variety of wheat, the cultivation conditions, etc.

Moreover, their herbicidal spectrum does not cover all hazardous weeds in wheat cultivation, and they are usually applied as mixtures.

Attempts have been made to apply 2-(2-chloro-4-ethylamino-s-triazin-6-ylamino)-2-methylpropionitrile [cyanazine; British Patent 1,132,306 patented October 30, 1968], 3,4-dimethyl-2,6-dinitro-N-(1 -ethyl pro- pyl)aniline [pendimethalin; German OLS 2,232,263 published January 11, 1973], alpha,alpha,alpha-tri fiuorn-2,6-dinitrn-N-(2-chlorn-ethyl) -N-propyl-p-toluidine [fluchloralin; German OLS 2,161,879 published June 20, 1973], a nd 2,4- and 2,4-dichloro-phenyl-3-methoxycarbonylA-nitrnphenylether [bifenox; U. S. Patent 3,784,635 issued January 8, 1974] as herbicides for controlling weeds in wheat cultivation. They are also used as mixtures, and when used singly, they exhibit only an insufficient efficacy against many hazardous weeds.

4-Chloro-2-butynyl-N-(3-chlorophenyl) carbamate [barban; U. S. Patent 2,906,614 issued September 29, 1959], N-benzoyl-N-(3,4-dichlornphenyl)-2-aminopropionic acid ethyl ester [benzoylprop-ethyl; Dutch Patent Application 6,717,715 filed July 1, 1968], 1,2-dimethyl-3,5-diphenyl-1H-pyrazolium methyl sulfate [difenzoquat; German OLS 2,441,504 published March 20, 1975] and (+)-2-[4-(2,4-dichlorophenoxy) phenoxy] propionic acid methyl ester [diclofop-methyl; German OLS 2,223,894 published December 13, 1973] are applied as agent for exclusively combatting wild oats, a very strongly hazardous weed, but their practical effect is not sufficient.

Other herbicides for wheat cultivation include, for example, 3-isopropyl-1H-2,1,3-benzothiazin-(4)-3H- one-2,2-dioxide [bentazon; South African Patent 6,705,164 patented January 23, 1968 and German OLS 1,913,850 published October 1, 1970] and 2-chloro-N-(4-methoxy-6-methyl-1 ,3,5-triazin-2-yl-aminocar- bonyl) benzenesulfonamide [chlorsulfuron; U. S. Patent 4,127,660 issued November 28, 1978] which has recently aroused interest as a highly active compound. The former is a compound having high safety to wheat, but its application is limited to certain broad-leaved weeds. The latter has an excellent soil treating effect at very low dosages with an outstanding residual activity, and also is highly safe to wheat.

However, even at low dosages, it is likely to cause phytotoxicity to crops grown in wheat fields after harvesting wheat. Accordingly, its use is greatly restricted. Nowadays, agricultural chemicals are required not only to have excellent activity but also to have high safety against humans and animals and their environment.

A number of studies have long been undertaken on N-phenylcarboxylic acid amide derivatives, and various excellent herbicides of this type have been known and used. They are disclosed, for example, in C. W. Hoffman et al., J. Agric. Food Chem., 8, 298 (1960) [N-(3,4-dichloro-phenyl) propionamide; propanil], British Patent 869,169 patented May 31, 1961 [karsil, solan], German Patent 1,166,547 patented May 26, 1964 [monalide], U. S. Patent 3,816,092 issued June 11, 1974, British Patent 885,043 patented May 4, 1959 [DCMA; dicryl], U. S. 3,277,107 issued October 4, 1966 [cypromid], U. S. Patent 4,166.735 issued September 4, 1979, and U. S. Patent 3,277,171 issued October 4, 1966. Many of these compounds kill weeds very effectively in foliar treatment and show a high level of selectivity for certain kinds of important crops.These compounds are also expected to decompose comparatively rapidly, and it is anticipated to some extent that their effect on crops to be grown after harvesting will be small and they will have little residual effects in the environment. Many of these prior art references, however, fail to dis close the selectivity of these compounds for wheat. The selectivities of compounds, which are disclosed in some of these references, are insufficient, or such compounds have an insufficient herbicidal efficacy.

In fact, the compounds disclosed in these prior art references are difficult to use in actual wheat cultivation.

Japanese Patent Publication No. 14240/1966 published on August 9, 1966 and German OLS 2,249,547 published on April 18, 1974 disclose the selectivity of N-phenylcarboxylic acid amide derivatives for wheat, but these compounds are not entirely satisfactory in their herbicidal efficacy against weeds and their phytotoxicity to crops. In particular, German OLS 2,249,547 disclose compounds of the following general formula

wherein R represents an alkyl group having 2 to 6 carbon atoms, R' represents an alkyl group having 2 to 8 carbon atoms, an alkenyl group having 3 to 6 carbon atoms or a cycloalkyl group having 3 to 8 carbon atoms, and X represents a halogen atom.A very few specific compounds, however, are actually cited in the specification as examples of the above compounds, and when R is an isopropyl group, only an ethyl group is shown as an example of R1. Furthermore, these compounds are not practically feasible for the reason given above.

Japanese Laid-Open Patent Publication No. 193806/1984 published on November 2, 1984 and Japanese Laid-Open Patent Publication No. 23357/1985 published on February 5, 1985 disclose N-(4-isopropylphenyl)carboxylic acid amide derivatives. These compounds, however, have the defect that their effects are unstable and they do not show herbicidal activity on some important weeds.

It has been strongly desired therefore to develop a chemical having essential selectivity for weeds in the cultivation of important gramineous crops, particularly wheat, a chemical which is little affected by physical factors such as soil conditions (i.e., foliar treating agents), a chemical which shows an efficacy in low dosages and has a broad herbicidal spectrum ranging from gramineous weeds to broad-leaved weeds, and a chemical which rapidly decomposes and does not exert deleterious effects such as environmental pollution.

It is desirable to provide a herbicide whose efficacy or phytotoxicity does not depend upon physical factors such as soil conditions in the cultivation of wheat which is an important gramineous crop.

It is further desirable to provide a highly selective herbicide which has essential selectivity for an important gramineous crop, particularly wheat, and produces an accurate control efficacy by simple foliar treatment in low dosages.

The present inventors studied many compounds in order to develop a highly selective herbicide for important gramineous crops, particularly wheat, and have now found that in foliar treatment, N-(3-substituted-4-isopropyl-phenyl) -2-methyl-2-pentenamide derivatives have an excellent selective herbicidal action and has a very broad herbicidal spectrum while causing no phytotoxicity to important gramineous crops, particularly wheat, even when applied in very high concentrations, and that these compounds solve the various problems described above.

Generally, compounds of the same series or structurally similar compounds are thought to have similar properties. But actually, it is not easy to infer such properties, and for example, by simply increasing the alkyl chain of one substituent in a herbicidal compound, the herbicidal activity of the compound against weeds or its phytotoxicity to crops varies greatly.

The N-(3-substituted-4-isopropylphenyl)-2-methyl-2-pentenamide derivatives in accordance with this invention are novel compounds represented by general formula (I) below

wherein Y represents a chlorine atom, a fluorine atom or a methyl group.

A herbicide comprising an N-(3-substituted-4-isopropylphenyl) -2-methyl-2-pentenamide derivative of general formula (I) as an active ingredient, when applied by foliar treatment, very effectively controls almost all hazardous upland farm weeds, for example strongly hazardous gramineous weeds such as wild oats (Avena fatua), meadow foxtail (Alopecurus pratensis), black grass- (Alopecurus myosuroides), annual bluegrass (Poa annua), water foxtail (Alopecurus aequalis), barnyard grass (Echinochloa oryzicola), crabgrass (Digitaria ciliaris) and green foxtail (Setaria viridis); and strongly hazardous weeds such as green amaranth (Amaranthas retroflexus), common purslane (Portulaca oleracea), cocklebur (Xanthium strumarium), cleavers (Galium spurium), lamb's quarters (Chenopodium album), chickweed (Stellaria media), tall morningglory (Ipomea purpurea), Cerastium holosteoides, velvet leaf (Abutilon theophrastl), oriented senna (Cassia obtusifolia), pick purse (Capsella bursapastoris), charlock (Sinapis arvensis), dayflower (Commelina communis), johnson grass (Sorghum helepense), speedwell (Veronica persica), Veronica caninotesticulate, hairly galinsoga (Galinsoga ciliata), common groundsel (Senecio vulgaris), matricaria (Matricaria chamomllla), and Urtica. On the other hand, no phytotoxicity of this herbicide to important gramineous crops, particularly wheat, is observed.

The compound of this invention shows the highest activity and the best stability of its effect when Y in formula (I) is a chlorine atom.

Thus, the N-(3-substituted-4-isopropylphenyl)-2-methyl-2-pentenamide derivatives of this invention have essential foliar treatment selectivity in the cultivation of important gramineous crops, particularly wheat, and can be very safely used. Various herbicides now in use in the cultivation of wheat are soil treating agents. The defects of these herbicides, that is, variations in efficacy and phytotoxicity by physical factors such as soil conditions, are not at all observed in the herbicide of this invention. Furthermore, the herbicide of this invention has little effect on crops cultivated in the same field after harvesting of wheat.

The N-(3-substituted-4-isopropylphenyl)-2-methyl-2-pentenamide derivatives in accordance with this invention can be easily synthesized by reacting a 3-substituted-4-isopropylaniline (general formula II) with a 2-methyl-2-pentenoic acid halide (general formula (III) or 2-methyl-2-pentenoic an hydride in accordance with the following reaction scheme.

In the above scheme, Y represents a chlorine atom, a fluorine atom or an ethyl group, and X represents a halogen atom.

The reaction is carried out in the absence of solvent or in an inert solvent. Examples of the inert solvent include aromatic hydrocarbons such as benzene, toluene, xylene, chlorobenzene and dichlorobenzene, ketones such as acetone and methyl ethyl ketone, nitriles such as acetonitrile and propionitrile, ethers such as ethyl ether, tetrahydrofuran and dioxane, and aprotic polar solvents such as dimethylformamide, dimethyl sulfoxide and hexamethylphosphoramide. In using the acid halide or acid anhydride, an organic base such as triethylamine, pyridine, dimethylaniline or 1,8-diazabicyclo (5,4,0)-7-undecene or an inorganic base such as potassium carbonate, sodium carbonate, sodium hydroxide, potassium hydroxide or sodium hydrogen carbonate may be used, as required, as an acid binder.The reaction temperature is -10 to 150"C, preferably 5 to 900C, more preferably 15 to 70"C. The reaction may also be carried out at the refluxing temperature of the solvent used. The reaction time differs according to the reaction temperature or the solvent used. Generally, it is 1 second to 10 hours, preferably 1 minute to 5 hours, more preferably 20 minutes to 3 hours.

The rate of application of the N-(3-substituted-4-isopropylphenyl)-2-methyl-2-pentenamide derivative as a herbicide can be selected according to the extent to which the growth of weeds is required to be inhibited. The standard rate of application is 0.1 to 10 kg per hectare, preferably 0.2 to 3 kg per hectare.

The herbicide of this invention comprises the compound of general formula (I) as a main ingredient.

The compound of formula (I) may be directly used against plants to be treated. Generally, however, it is used in usual formulations containing a carrier and as required other adjuvants, such as a dust, granules, a wettable powder, an emulsifiable concentrate or a flowable agent.

Examples of the carrier are inorganic materials such as clays, talc, bentonite, calcium carbonate, diatomaceous earth, zeolite and silicic anhydride, organic materials of plant origin such as wheat flour, soybean meal, starch and crystalline cellulose, polymeric compounds such as petroleum resins, polyvinyl chloride and polyalkylene glycols, urea, and waxes. Liquid carriers such as oils, organic solvents and water may also be used.

Examples of the adjuvants are a wetting agent, a dispersing agent, a sticker, and a spreader which may, as required, be used either singly or in combination.

Various surface-active agents, polymeric compounds such as gelatin, albumin, sodium alginate, methyl cellulose, polyvinyl alcohol and xanthan gum, and other adjuvants may be cited as auxiliary agents which are used for the purpose of wetting, dispersion, spreading, stabilization of components or stabilization of properties. Industrial fungicides, bactericides and moldproofing agents may be added to flowable agents for killing fungi, bacteria or molds.

The surface-active agents may be nonionic, anionic, cationic and amphoteric. Examples of preferred surface-active agents include products of polymerization of ethylene oxide with alkylphenols, higher alco hols, alkyl-naphthols, higher fatty acids, fatty acid esters or dialkylphosphoric acid amines, a copolymer of ethylene oxide and propylene oxide, alkylsulfuric acid ester salts (such as sodium laurylsulfate), alkylsulfonic acid salts (sodium 2-ethylhexenesulfonate), and arylsulfonic acid salts (such as sodium ligninsulfonate, and sodium dodecylbenzenesulfonate).

The content of the compound of general formula (I) in the herbicide of this invention differs depending upon the formulation, and usually is 1 to 20% by weight for a dust, 20 to 90% by weight for a wettable powder, 1 to 30% by weight for granules, 1 to 50% by weight for an emulsifiable concentrate, 10 to 90% by weight for a flowable agent, and 20 to 70% by weight for a dry flowable agent The content of the adjuvants is 0 to 80% by weight, and the amount of the carrier is obtained by subtracting the contents of the active compound and the adjuvants from 100% by weight.

The herbicide of this invention may be applied in admixture with at least one other herbicide, other agricultural chemicals such as an insecticide or a plant growth regulator, a soil conditioner, and a fertilizer substance, or may be formulated into a mixed agent with such other chemicals. Sometimes, this manner of application is expected to give a synergistic effect.

The following examples illustrate the present invention more specifically.

Synthesis example Production of N-(3-chloro-4-isopropylphenyl)-2-methyl-2-pentenamide: To 30 ml of benzene were added 1.0 g (5.9 x 10-3 mole) of 3-chloro-4-isopropyianiline and 0.6 g of triethylamine. Furthermore, 0.8 g (6.0 x 10-3 mole) of 2-methyl-2-pentenoyl chloride was added, and the mixture was stirred at room temperature for 30 minutes. The crystals that precipitated were separated by filtration, and 100 ml of benzene was added to the filtrate. The mixture was washed with a saturated aqueous solution of sodium hydrogen carbonate, dried over anhydrous sodium sulfate, and concentrated by an evaporator. The resulting crude crystals were recrystallized from a mixed solvent of hexane and benzene (2:1, v/v) to give 1.4 g of N-(3-chloro-4-isopropylphenyl)-2-methyl-2-pentenamide as crystals in a yield of 89.3% based on 3-chloro-4-isopropylaniline.

Compounds of general formula (I) in which Y is a fluorine atom or a methyl group may also be synthesized substantially in accordance with the above procedure.

The compounds of general formula (I) and their properties are shown in Table 1.

In Formulation Examples and Test Examples given hereinbelow, the active compounds are shown by the compound numbers given in Table 1.

TABLE 1

Com- Substipound tuent Y Properties No. in (I) IR vKsax cm : 3320, 1665 NMR 8cM54: 0.95 (3H, t, J=8Hz), 1.18 (6H, d, J=8Hz), 2.10 (2H, m), 3.25 (1H, m), 6.30 (1H, m), 7.05 (1H, d, J=9Hz), 7.40 1 Cl (1H, dd, J=9Hz, J=2Hz), 7.58 (1H, d, J=2Hz), m.p.: 71.0-73.0 C Elemental analysis (%): Calc. (%) C; 67.78, H; 7.59, N; 5.27, Cl; 13.34 Found (%) C;67.43, H; 7.66; N; 5.13, Cl; 13.64 IR #maxKBr cm-1: 3250, 1655 NMR 8TCWs4 1.05 (3H, t, J=8Hz), 1.21 (6H, d, J=8Hz), 1.85 (3H, s), 2.20 (2H, m), 3.20 (1H, m), 6.30 (1 H, m), 7.00-7.35 (3H, m) 2 F m.p.: 79.0-80.0 C Elemental analysis (%): Calc. (%) C; 72.25, H; 8.09, N; 5.62, F; 7.69 Found (%) C;71.98, H; 7.99, N; 5.73, F; 7.48 IR vKsar cm 1 3310, 1660 NMR 8TM54: 0.95 (3H, t, J=8Hz), 1.15 (6H, d, J=8Hz), 1.80 (3H, s), 2.10 (2H, m), 2.17 (3H, s), 3.05 (1H, m), 6.30 (1H, m), 3 CH3 7.02 (1H, m), 7.35 (2H, m) m.p.: 43.0-46.0 C Elemental analysis (%): Calc. (%) C; 78.32, H; 9.46, N 5.71 Found (%) C; 77.96, H; 9.65, N; 5.52 Examples are given below to illustrate the formulation of the herbicide of this invention and its herbicidal activity.

Formulation Example 1 Wettable powder: Twenty parts by weight of compound No. 1, 2 parts by weight of sodium alkylbenzenesulfonate, 2 parts by weight of polyoxyethylene alkylphenyl ether and 76 parts by weight of Zieklite (trademark of Zieklite Chemical Industry Co., Ltd.; a carrier containing silica as a main ingredient) were well pulverized and mixed to form a wettable powder.

Formulation Example 2 Wettable powder: Thirty parts by weight of compound No. 3, 6 parts by weight of polyoxyethylene alkylphenyl ether ammonium sulfate, 2 parts by weight of sodium naphthalenesulfonate/formaldehyde condensate, 1 part by weight of sodium alkylbenzenesulfonate, 2 parts by weight of polyvinyl alcohol and 59 parts by weight of diatomaceous earth were well pulverized to form a wettable powder.

Formulation Example 3 Wettable powder: Fifty parts by weight of compound No. 2, 3 parts by weight of white carbon, 4 parts by weight of polyoxyethylene alkyl phenyl ether ammonium sulfate, 2 parts by weight of sodium alkylbenzenesulfonate and 41 parts by weight of diatomaceous earth were well pulverized and mixed to form a wettable powder.

Formulation Example 4 Wettable powder: Fifty-five parts by weight of compound No. 2, 5 parts by weight of white carbon, 4 parts by weight of polyoxyethylene alkylphenyl ether ammonium sulfate, 2 parts by weight of sodium ligninsulfonate and 34 parts by weight of diatomaceous earth were well pulverized and mixed to form a wettable powder.

Formulation Example 5 Wettable powder: Eighty parts by weight of compound No. 1, 5 parts by weight of white carbon, 7 parts by weight of polyoxyethylene alkylphenyl ether ammonium sulfate, 2 parts by weight of sodium naphthalenesulfonate/ formaldehyde condensate, 2 parts by weight of sodium alkylbenzenesulfonate, and 4 parts by weight of diatomaceous earth were well pulverized and mixed to form a wettable powder.

Formulation Example 6 Flowable agent: Water (76.7 parts by weight) was mixed with 20 parts by weight of compound No. 1, 2 parts by weight of sodium ligninsulfonate, 0.3 parts by weight of xanthan gum and 1 part by weight of polyoxyethylene alkylaryl ether, and the mixture was finely pulverized by a sand grinder to form a flowable agent.

Formulation Example 7 Flowable agent: Water (52.8 parts by weight) was added to 40 parts by weight of compound No. 2, 3 parts by weight of sodium naphthalenesulfonate/formaldehyde condensate, 2 parts by weight of sodium ligninsulfonate, 0.1 part by weight of xanthan gum, 0.1 part by weight of Deltop (registered trademark of Takeda Chemical Co., Ltd.; industrial fungicide containing an organic iodine acetamide compound as a main active ingredient) and 2 parts by weight of polyoxyethylene alkylaryl ether, and the mixture was finely pulverized by a sand grinder to form a flowable agent.

Formulation Example 8 Dust: Three parts by weight of compound No. 1, 3 parts by weight of sodium ligninsulfonate, 2 parts by weight of polyoxyethylene alkylaryl ether and 92 parts by weight of clay were mixed and pulverized to form a dust.

Formulation Example 9 Dust: Twenty parts by weight of compound No. 3, 5 parts by weight of sodium ligninsulfonate, 4 parts by weight of polyoxyethylene alkylaryl ether and 71 parts by weight of clay were mixed and pulverized to form a dust.

Formulation Example 10 Dry flowable agent: Sixty parts of compound No. 1, 5 parts by weight of sodium alkylbenzenesulfonate and 35 parts by weight of polypropylene glycol polyethylene glycol ether were finely pulverized by using a jet-O-miser to form a dry flowable agent.

Formulation Example 11 Dry flowable agent: Seventy parts by weight of compound No. 2, 2 parts by weight of sodium alkylbenzenesulfonate, 18 parts by weight of polypropylene glycol polyethylene glycol ether and 10 parts by weight of white carbon were finely pulverized by using a jet-O-miser to form a dry flowable agent.

Formulation Example 12 Granules: Finely pulverized compound No. 3 (20.5 parts by weight), 2.0 parts by weight of Gohsenol GL-5S (trademark of Nihon Synthetic Chemical Co., Ltd.; polyvinyl alcohol), 2.0 parts by weight of Sunexs P-252 (trademark of Sanyo Kokusaku Pulp Co., Ltd.; sodium ligninsulfonate) and 75.5 parts by weight of clay were well mixed, and then a suitable amount of water was added to wet the mixture. The mixture was then extruded by an injecting former to produce granules. The granules were air-dried at 60 to 70"C, crushed, and adjusted to a granule diameter of 0.3 to 1 mm by a size adjusting machine.

Formulation Example 13 Granules: Five parts by weight of finely pulverized compound No. 1, 72 parts by weight of bentonite, 20 parts by weight of talc, 2 parts by weight of calcium dodecylbenzenesulfonate and 1 part by weight of calcium ligninsulfonate were well mixed, and a suitable amount of water was added to wet the mixture. The mixture was extruded by an injecting former to form granules. The granules were air-dried at 60 to 90"C, crushed and adjusted to a diameter of 0.5 to 1.2 mm.

Formulation Example 14 Granules: Twelve parts by weight of finely pulverized compound No. 2, 60 parts by weight of bentonite, 25 parts by weight of talc, 2 parts by weight of sodium naphthalenesulfonate/formaldehyde condensate and 1 part by weight of dioctyl sulfosuccinate were well mixed, and a suitable amount of water was added to wet the mixture. The mixture was extruded by an injecting former to form granules. The granules were airdried at 60 to 900C, crushed, and adjusted to a diameter of 0.3 to 1 mm.

Formulation Example 15 Emulsifiable concentrate: Ten parts by weight of compound No. 2, 10 parts by weight of Sorpol 800A (trademark of Toho Chemical Co., Ltd.; a mixture of nonionic and anionic surfacants) and 80 parts by weight of benzene were mixed and dissolved to form an emulsifiable concentrate.

Formulation Example 16 Emulsifiable concentrate: Fifty parts by weight of compound No. 3, 15 parts by weight of Gafac RS-610 (trademark of General Aniline & Film Corporation; polyoxyethylene phosphate) and 35 parts by weight of o-xylene were mixed and dissolved to form an emulsifiable concentrate.

Formulation Example 17 Emulsifiable concentrate: Twenty-five parts of compound No. 1, 15 parts by weight of Plysurf A-210G (trademark of Dai-ichi Kogyo Seiyaku Co., Ltd.; polyoxyethylene phosphate) and 60 parts by weight of o-xylene were mixed and dissolved to form an emulsifiable concentrate.

Test Example 1 Plastic pots (1/10,000 a) were filled with the soil taken from an upland farm, and seeds of one kind of test plant were sown in each pot and grown in a greenhouse. When each plant grew to a stage of 2 or 3 leaves, each of the test compounds was dissolved in acetone containing polyoxyethylene sorbitan monooleate and sorbitan monolaurate. The solution was sprayed by a pressure microsprayer at a rate of 2 kiloliters per hectare. On the 21st day after the spraying of the chemical, the effects of the chemical on the crops and weeds were observed and examined. The results are shown Table 2. The degree of injury to the test plants was evaluated on the following scale.

Degree of Rating injury (%) State of the injury 5 100 Withered (complete control of weeds) 4 80 Enormous injury (80% weed control) 3 60 Medium injury (60% weed control) 2 40 Small injury (40% weed control) 1 20 Slight injury (20% weed control) 0 0 No injury (no weed control) The control compounds shown in Table 2 were as follows: A: N-(3,4-dichlorophenyl)propionamide (propanil) B: N-(3,4-dichlorophenyl)-2-methylpentanamide (karsil) [British Patent 869,169] C: N-(3-chloro-4-methylphenyl)-2-methylpentanamide (solan) [British Patent 869,169) D:N-(3,4-dichlorophenyl)methacrylamide (dicryl) [British Patent 885,043] TABLE 2 Test Control Invention Compound A B C D 1 2 3 Concen tration 1 2 5 1 2 5 1 2 5 1 2 5 1 2 5 1 2 5 1 2 5 (x1000 ppm) (a) 4 5 5 3 5 5 3 5 5 3 4 5 5 5 5 5 5 5 5 5 5 (b) 5 5 5 5 5 5 4 5 5 4 5 5 5 5 5 4 5 5 4 5 5 (c) 3 5 5 4 4 5 3 5 5 3 4 5 4 5 5 3 4 5 3 4 5 (d) 1 2 2 0 1 2 1 1 2 0 1 1 2 3 4 2 3 4 2 2 3 (e) 3 3 4 2 2 3 2 3 3 2 2 3 5 5 5 4 5 5 4 5 5 (f) 5 5 5 4 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 Weed (g) 4 5 5 4 5 5 5 5 5 4 5 5 5 5 5 5 5 5 5 5 5 (h) 5 5 5 5 5 5 5 5 5 4 5 5 5 5 5 5 5 5 4 5 5 (i) 5 5 5 4 5 5 4 4 5 4 4 5 5 5 5 4 5 5 5 5 5 (j) 5 5 5 5 5 5 5 5 5 4 5 5 5 5 5 5 5 5 5 5 5 (k) 2 4 5 2 2 4 2 3 4 2 3 5 5 5 5 4 5 5 4 5 5 (A) 2 3 4 3 4 5 2 2 3 2 3 3 5 5 5 5 5 5 5 5 5 (r) 0 1 2 2 3 3 2 3 3 2 3 3 2 3 3 2 2 3 2 2 3 (s) 2 3 3 1 2 3 2 2 3 2 3 3 0 0 1 0 0 1 0 0 1 Crop (t) 1 2 3 1 2 3 2 2 3 2 3 3 2 2 2 2 2 3 2 3 3 (u) 2 2 3 1 2 3 1 2 3 2 3 3 0 1 2 0 1 2 0 0 2 (v) 2 3 4 1 2 3 2 2 3 2 3 3 2 2 3 2 2 2 2 2 2 Test Example 2 A plastic planter (1/1,000 a) was filled with the soil from an upland farm, and seeds of wild oats, water foxtail, annual bluegrass, chickweed, lamb's quarters and black bindweed as weeds were sown in the planter. Simultaneously, seeds of wheat (variety: Norin No. 61) and barley (variety: Tochigi Sekitori No.

1) as crops were sown in the planter. These plants were cultivated in a phytotron (12 - 18"C). When wheat grew to a stage of 2 or 3 leaves, a predetermined amount of each of the test compounds formulated as in Formulation Example 15 was diluted with water in an amount corresponding to 500 liters per hectare, and applied by a micro-sprayer. In the third week after the treatment with the chemical, the effects of the chemical on the weeds and crops were observed and evaluated. The results are shown in Table 3. The degree of injury to the test plants was rated as in Test Example 1.

The control compounds indicated in Table 3 were as follows: E: N-(4-isopropylphenyl)-2-methyl-2-pentenamide (Japanese Laid-Open Patent Publication No. 23357/ 1985) F: N-(3-chloro-4-isopropylphenyl)propionamide (West German Patent 2,249,547) G: N-(3-chloro-4-methylphenyl)-2-methyl-2-pentenamide (British Patent 885,043) TABLE 3 Test Control invention Compound E F G 1 2 3 Concen tration 1 2 4 1 2 4 1 2 4 1 2 4 1 2 4 1 2 4 (x1000 ppm) (d) 0 0 1 1 1 2 1 1 1 3 4 5 3 4 5 3 4 5 (m) 2 2 3 1 1 2 2 2 3 4 5 5 4 4 5 4 4 5 (e) 2 3 4 1 1 2 2 3 4 4 4 5 4 4 5 4 4 5 Weed (h) 2 2 4 2 2 4 2 3 4 5 5 5 4 4 5 4 4 5 (9) 5 5 5 3 5 5 5 5 5 5 5 5 4 5 5 4 5 5 (i) 1 2 3 1 1 2 1 3 3 5 5 5 5 5 5 5 5 5 (n) 2 3 4 1 2 3 2 3 3 5 5 5 5 5 5 5 5 5 (s) 0 0 0 1 2 2 1 1 2 0 0 0 0 0 1 0 0 1 Crop (w) 0 0 0 1 2 3 1 2 2 0 0 1 0 0 0 0 0 1 Test Example 3 Test in a wheat field: A field test for wheat cultivation was conducted in October 1984 in Chigasaki City, Kanagawa, Japan.

Seeds of wheat (variety: Norin No. 61) and barley (variety: Tochigi Sekitori No. 1) were sown on October 19. All the weeds were allowed to occur spontaneously. On November 13, each of the test chemicals was sprayed in an amount corresponding to 500 liters per hectare by means of a battery-driven sprayer. At this time, wheat was in the stage of 3 leaves, and barley, in the stage of 2.5 leaves. Test areas each measured 2 m x 2.5 m in size, and the test was conducted through 2 replicates. On December 4 which was 41 days after the spraying of the chemical, the effects of the chemical were evaluated. The degree of injury to the test plants was rated on a scale of 11 grades in which "10" means complete kill and "0" means no effect. The results are shown in Table 4. Each rating assigned was an average of the ratings in the two replicates.

The compounds of this invention were used in the form of an emulsifiable concentrate prepared in accordance with Formulation Example 17. The control compounds used were commercial Stam (emulsifiable concentrate), Tribunil (wettable powder) and Basagran (liquid preparation).

Stam: trademark of Rohm & Haas Company; a herbicide containing N-(3,4-dichlorophenyl)propionamide (propanil) as a main active ingredient Tribunil: trademark of Bayer A. G.; a herbicide containing 3-(2-benzothiazol-2-yl)-1,3-dimethylurea (methabenzthiazuron) as a main active ingredient Basagran: trademark of BASF A. G., a herbicide containing 3-isopropyl-1H-2,1,3-benzothiadiazin-4(3H)one 2,2-dioxide as a main active ingredient.

TABLE 4 Test Control Invention Compound Stam Tribunil Basagran 1 2 3 Amount (kg/ha) 0.5 1.0 1.5 0.5 1.0 1.5 0.5 1.0 1.5 0.5 1.0 1.5 0.5 1.0 1.5 0.5 1.0 1.5 (h) 6.0 7.5 7.5 7.0 8.0 9.0 7.0 8.0 8.0 8.0 10.0 10.0 8.0 10.0 10.0 8.0 9.0 9.0 (o) 5.5 8.0 8.0 6.0 7.5 8.0 6.0 7.0 8.0 9.5 10.0 10.0 9.0 9.5 10.0 9.0 10.0 10.0 (p) 2.2 7.0 7.5 4.0 5.5 8.0 0.0 0.5 1.0 8.0 9.0 10.0 8.0 9.0 10.0 7.0 8.0 9.5 Weed (q) 5.0 8.5 10.0 2.5 8.0 9.0 2.0 9.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 (m) 0.0 0.5 1.0 0.0 1.5 4.0 0.0 0.0 0.0 5.0 8.0 10.0 5.0 8.0 10.0 5.0 8.0 10.0 (e) 0.0 1.0 1.5 1.0 2.5 4.0 0.0 0.0 0.0 5.0 8.0 10.0 4.0 7.5 10.0 4.0 7.5 9.5 (s) 2.0 3.0 4.0 0.0 1.0 1.5 0.0 0.0 0.0 0.0 0.0 0.5 0.0 0.0 0.0 0.0 0.0 0.0 Crop (w) 1.0 2.0 3.5 1.0 1.5 1.5 0.0 0.0 0.0 0.0 0.0 0.5 0.0 0.0 0.5 0.0 0.0 0.0 The abreviations used to indicate the plants tested in Tables 2, 3 and 4 have the following meanings.

English Scientific nomenclature (a) crabgrass Digitaria ciliaris (b) green foxtail Steria viridis (c) barnyard grass Echinochloa oryzicola (d) wild oats Avena fatua L.

(e) annual bluegrass Poa annua L.

(f) green amaranth Amaranthas viridis L.

(g) lamb's quarters Chenopodium album (h) chickweed Stellaria media (i) charlock Sinapis arvensis (j) black bindweed Polygonum convolvulus (k) cocklebur Xanthium strumarium (e) morninglory Ipomea purpurea (m) water foxtail Alopecurus aequalis (n) matricaria Matricaria chamomilla (o) pick purse Capsella brusa-pastoris (p) hen bit Lamium amplexicaule (q) speedwell Veronica persica (r) rice Oryza sativa (s) wheat Triticum (t) maize Zea mays (u) peanut Arachis hypogaea (v) soybean Glycine max (w) barley Hordeum vulgare The foregoing test results demonstrate that the herbicides containing the compounds of this invention show a marked herbicidai efficacy at low dosages against all weeds tested by a foliar treatment not affected by the soil while showing outstanding selectivity for useful gramineous crops, particularly wheat, and that they excell the control chemicals (such as methabenzthiazuron, bentazon, propanil, karsil, etc.) or other known compounds.

Claims (16)

1. An N-(3-su bstituted-4-isopropylphenyl)-2-methyl-2-pentenamide derivative represented by the following general formula

wherein Y represents a chlorine atom, a fluorine atom or a methyl group.

2. The compound of claim 1 wherein Y is a chlorine atom.

3. The compound of claim 1 wherein Y is a fluorine atom.

4. The compound of claim 1 wherein Y is a methyl group.

5. A process for producing an N-(3-substituted-4-isopropylphenyl) -2-methyl-2-pentenamide derivative represented by the following general formula (I)

wherein Y represents a chlorine atom, a fluorine atom or a methyl group, which comprises reacting an aniline represented by the following general formula (II)

wherein Y is as defined, with a 2-methyl-2-pentenoic acid derivative of the general formula (III)

wherein X is a halogen, or with 2-methyl-2-pentenoic acid anhydride.

6. A selective herbicide comprising an N-(3-substituted-4-isopropylphenyl)-2-methyl-2-pentenamide derivative represented by the following general formula

wherein Y represents a chlorine atom, a fluorine atom or a methyl group, as an active ingredient.

7. A coinpound of any one of claims 1 to 4 for use in herbicidal treatment of a crop.

8. A compound of claim 7 wherein the crop is gramineous.

9. A compound of claim 8 wherein the crop is wheat.

10. The use of a compound of any one of claims 1 to 4 in preparing a selective herbicide.

11. A method of herbicidal treatment which comprises applying a compound of any one of claims 1 to 4.

12. A method according to claim 11 wherein the compound is applied to a growing crop.

13. A method according to claim 12 wherein the crop is graminaceous.

14. A method according to claim 13 wherein the crop is wheat.

15. A herbicide formulation according to claim 6 substantially as described herein.

16. A method of herbicidal treatment according to claim 11 substantially as described herein.