GB2075018A - Herbicidal 4-[4- (anilino)phenoxy]-2-pentenoic Acid Derivatives - Google Patents

Abstract

Herbicidal pentenoic acid derivatives are of formula <IMAGE> wherein R1 represents Cl, Br or CF3; R2 represents Cl, Br or NO2; R3 represents H, alkyl, alkenyl; and R4 represents H, alkyl, an alkali or alkaline earth metal cation or an amino cation.

Description

SPECIFICATION Pentenoic Acid Derivatives The present invention relates to novel compounds to selective herbicide including The same and also to processes for the preparation thereof. More particularly, the present invention provides 4-(4anilino-phenoxy)-2-pentenoic acid derivatives represented by the general formula (I):

wherein R1 represents a chlorine or bromine atom or a trifluoromethyl radical, H2 represents a chlorine or bromine atom or a nitro radical, R3 represents a hydrogen atom or a lower alkyl or alkenyl radical, and R4 represents a hydrogen atom, a lower alkyl radical, an alkali metal cation, an alkaline earth metal cation or an amine cation.

Preferred compounds according to the invention are those of general formula (ill):

wherein R1, R2, R3 and R4 are as defined for formula (I).

We succeeded in synthesising the pentenoic acid derivatives represented by the formula (I) just defined and we furthermore found that these compounds exhibit an excellent selective herbicidal effect.

Thus, the compounds of the present invention have an excellent selective herbidical effect for the gramineae weeds such as barnyard grass, crabgrass, foxtail (Setaria viridis), without any substantial harm to foliated plants such as radish, pea plant (pisum sativum), spinach, soybean, red bean plant, sugar beet, potato.

in the case of post-emergence treatment, the. compounds of the present invention have any effect on broad leaf plants such as radish, pea plant, spinach, soya, red bean plant, sugar beat, potato plant even when a large amount of the compounds sufficient to kill the gramineae weeds such as mannagrass is used. In the case of soil treatment before the germination of weeds, when the compounds according to the invention are applied even at a dose for interrupting radically the germination of crabgrass and foxtail etc. they scarcely influence the seeds of foliated plants and are therefore very useful in broad fields of application.

Furthermore, the compounds of the invention have a strong herbicidal effect on barnyard grass which is particularly harmful for the cultivation of paddy rice plant, while their selectivity in the protective effect on rice plant is improved. Before and after the germination, the compounds of the present invention do not manifest substantial influence on the growth of rice plant even at a dose which is detrimental to barnyard grass. They show higher activity to established barnyard grass which has been found relatively difficult to be killed using conventional herbicides, and moreover they are found to maintain their effect over a long period of time such that they are employable in the cultivation of rice plant widely from seeding to transplantation of the rice plant.

Thus, the present invention also provides a herbicidal composition which comprises at least one compound of the general formula (I) together with a carrier or diluent therefor.

The compounds of the present invention may be prepared, for example, by the processes illustrated in the following reaction schemes. In the formulae, Hal represents a halogen atom, R1, R2 and R3 represent a radical as defined hereinbefore in the general formula (II).

Reaction scheme (1)

Reaction scheme (2)

The above-shown reactions (1) and (2) can be executed generally at a temperature from 0 C to 1 500C in an inert solvent in the presence of a dehydrohalogenation agent.

The compound of the invention wherein R3 represents a lower alkyl or alkenyl radical can be prepared by the following reaction scheme (3).

Reaction scheme (3)

Examples of a suitable reaction solvent include water, ketones such as acetone or methyl-ethyl ketone, aromatic hydrocarbons such as benzene, toluene or xylene, ethers such as ethyl ether, tetrahydrofuran or dioxane, alcohols such as methanol, ethanol, isopropanol or butanol, and haiogenated hydrocarbon such as chlorobenzene, chloroform, tetrachlorocarbon or dichloroethane dimethyl formamide or dimethyl sulfoxide.

Examples of the bases employable as dehydrohalogenation agent include alkali metal hydroxides such as sodium hydroxide or potassium hydroxide, and alkali metal carbonates such as sodium carbonate, potassium carbonate or sodium bicarbonate, and alcoholate such as sodium ethoxide, and tertiary amine such as triethyl amine, dimethyl aniline or pyridine.

The resulting ester is hydrolyzed by the addition of alkali to prepare a compound of the present invention wherein R4 in the above general formula represents a hydrogen atom. A compound of the present invention wherein R4 in the above general formula denotes an alkali metal cation, alkali-earth metal cation or amine cation can be prepared, for example, by the reaction of the acid obtained in the above manner with an alkali hydroxide or amine in the medium of water or a suitable organic solvent.

Typical compounds of the present invention and their properties are illustrated in the following Table 1.

Table 1 Cpd. No. R1 R2 R3 R4 Physic. Property 1 Cl Cl H CH3 m.p. 101-102.5 2 Cl Cl H C4H9 nD25=1.5810 3 Cl Cl H C2H5 m.p. 72-73 4 Cl Cl CH3 C2H5 nD25=1.5848 5 Br Cl H C2H5 m.p. 71-72 6 CF3 NO2 H CH3 Oily product, dark red 7 CF NO2 H C2H5 m.p.71-730 8 CF3 NO2 H C4H9 Oily product, dark red 9 Cl NO2 H CH3 m.p. 88-89.5 10 Cl NO2 H C2H5 m.p. 64.5-66.5 11 Cl NO2 CH2CH:CH2 C2H5 Oily product, dark red 12 Br NO2 H C2H5 nD25=1.6375 13 Br NO2 H C4H9 Oily product, dark red Among the above No. 1-No. 13 compounds of the present invention, No. 3, No. 4, No. 5, No. 6 and No. 13 compounds are further illustred in particular concerning their physical and chemical characteristics.

No. 3 compound

(1) Nuclear magnetic resonance spectrum (solvent: CC14)

1 #=1.31 ppm (t) and 6 #=1.51 ppm (d) 6H 2 #=4.24 ppm (q) 2H 5 #=4.93 ppm (p) 1H 3 #=6.06 ppm (d) and 8 #=5.93 ppm (s) 2H 4, 7, 9, 10=6.75-7.4 ppm (mc) 8H (2) Infrared spectrum (KBr) 3350 cm-1 stretching vibration of N-H 2960-2850 cm-1 stretching vibration of C-H 1699 cm-1 stretching vibration of C=O in ester 1641 cm-1 stretching vibration of C=C 1591 cm-1 stretching vibration of benzene ring 1507 cm-1 deformation vibration of N-H 1462 cm-1 deformation vibration of CH3 1358 cm-1 stretching vibration of Carom-N 1280, 1041 cm-1 stretching vibration of C-O in ester 1257 cm-1 stretching vibration of C-O in aromatic ether 967 cm1 deformation vibration out-of-plane CH of C=C-H 850, 800 cm1 deformation vibration out-of-plane CH of benzene ring (3) elementary analysis C19H19Cl2NO3 calculated found C 60.01 60.1 H 5.04 4.9 N 3.68 3.8 t4) mass opectrum parent peak M/e=379 (molecular weight 379) fragment peak 333 305 209 No. 4 compound

(1) nuclear magnetic resonance spectrum (solvent: :C-DCl3) 10 8 6 H H CH3 H H CH3 Cl- -N- -0-CH-CH=CH-COOCH2CH3 H Cl H H 5 4 3 2 9 7 1=1.28 ppm (t) and 6=1.44 ppm (d) 6H 8=3.19 ppm (s) 3H 2=4.20 ppm (q) 2H 5=4.81 ppm (p) 1 H 3=6.04 ppm (d) 1 H 4 7 9 10=6.45-7.6 ppm (mc) 8H (2) Infrared spectrum (NaCI) 3100-2700 cm1 stretching vibration of C-H 1715 cm-1 stretching vibration of C=O in ester 1655 cm1 stretching vibration of C=C 1580 cm-1 streching vibration of benzene ring 1498, 1477 cm1 deformation vibration of CH3 1356 cm-1 stretching vibration of Carom-N 1296, 1037 cm-1 stretching vibration of C-O in ester 1255 cm1 stretching vibration of C-O in aromatic ester 1220, 1 665 cm-1 stretching vibration of C-N 968 cm1 deformation vibration out-of-plane CH of C=C-H 855, 808 cm1 deformation vibration out-of-plane CH of benzene ring (3) Elementary analysis C20H21Cl2NO3 calculated found C 60.92 59.5 H 5.37 5.1 N 3.55 3.7 (4) Mass spectrum Main peak M/e=393 (molecular weight 393) Fragment peak 348 266 252 No. 5 compound

(1) Nuclear magnetic resonance spectrum (solvent::CDCI3)

1 #=1.36 ppm (t) and 6 #=1.41 ppm (d) 6H 2 #=4.15 ppm (q) 2H 5 #=4.84 ppm (p) 1 H 3 #=6.00 ppm (d) and 8 #=5.87 ppm (s) 2H 4, 7, 10 #=6.65-7.3 ppm (mc) 7H 9 #=7.38 ppm (d) 1H (2) Infrared spectrum (KBr) 3350 cm-1 stretching vibration of N-H 3100-2700 cm1 stretching vibration of C-H 1699 cm1 stretching vibration of C=O in ester 1641 cm-1 stretching vibration of C=C 1591 cm1 stretching vibration of benzene ring 1507 cm-1 deformation vibration of N-H 1458 cm-1 deformation vibration of CH3 1359 cm-1 stretching vibration of Carom-N 1285, 1042 cm-1 stretching vibration of C-O in ester 1248 cm-1 stretching vibration of C-O in aromatic ester 967 cm-1 deformation vibration out-of-plane CH of C=C-H 850, 800 cm-1 deformation vibration of benzene ring (3) Elementary analysis C19H19BrCINO3 calculated found C 53.73 53.4 H 4.51 4.5 N 3.30 3.2 (4) Mass spectrum Parent peak M/e=423 (molecular weight 423) Fragment peak 378 296 No. 6 compound

(1) Nuclear magnetic resonance spectrum (solvent:CCl4)

5 #=1.52 ppm (d) 3H 1 #=3.72 ppm (s) 3H 4 #=4.95 ppm (d) 1H 2 S=5.96 ppm (d, d) 1 H 3, 6, 9 #=6.7-7.7 ppm (mc) 7H 8 #=8.50 ppm (s) 1H 7 #=9.64 ppm (s) 1H (2) Infrared spectrum (NaCI) 3350 cm-1 stretching vibration of N-H 3025-3100 cm-1 stretching vibration of C-H in benzene ring 2975-2830 cm-1 stretching vibration of aliphatic C-H 1728 cm1 stretching vibration of C=O in ester 1637 cm-1 stretching vibration of C=C 1 575, 1350 cm1 stretching vibration of NO2 radical 1 530, 1 505, 1440 cm-1 deformation vibration of N-H and C-H 1320, 1115 cm1 stretching vibration of C-F 1240-1210, 1150 cm1 stretching vibration of C-O-C 975 cm1 deformation vibration out-of-plane CH of C-C-H 844-820 cm-1 deformation vibration of benzene ring (3) Elementary analysis C19H17F3N2O5 calculated found C 55.61 55.1 H 4.18 4.3 N 6.83 7.0 (4) Mass spectrum peak M/e=410 (molecular weight 410) Fragment peak 379 No. 13 compound

(1) Nuclear magnetic resonance spectrum (solvent:CCl4)

7 #=0.93 ppm (t) 3H 2, 3 #=1.13-1.83 ppm (mc) and 7H 8 #=1,48 ppm (d) 4 #=3.94 ppm (t) 2H 7 #=4.85 ppm (p) 1 H 5 #=5.86 ppm (dd) 1 H 8, 9, 12 #=6.6-7.4 (mc) 7H O S=8.12 ppm (d) 1H 10 #=9.22 ppm (s) 1 H (2) Infrared spectrum (NaCI) 3350 cm1 stretching vibration of N-H 3085-3036 cm1 stretching vibration of C-H in benzene ring 2950-2850 cm1 stretching vibration of aliphatic C-H 1717 cm1 stretching vibration of C=O in ester 1658 cm1 stretching vibration of C=C 1613 cm1 stretching vibration of benzene ring 1 562, 1 339 cm1 stretching vibration of NO2 radical 1500 cm1 deformation vibration of aliphatic CH 1250, 1050 cm1 stretching vibration of C-O-C 970 cm-1 deformation vibration out-of-plane CH of C=C-H 890, 852, 839, 809 cm-1 deformation vibration of benzene ring (3) Elementary analysis C21H23BrN205 calculated found C 54.43 54.1 H 5.00 5.1 N 6.04 6.2 (4) Mass spectrum Parent peak M/e=462 (molecular weight 462) Fragment peak 389 The spectra of certain compounds according to the invention are illustrated in the accompanying drawings wherein:: Fig. 1, Fig. 2, Fig. 3, Fig. 4 and Fig. 5 illustrate the nuclear magnetic resonance spectrum of compound No. 3, No. 4, No. 5, No. 6 and No. 3 of the present invention respectively. Fig. 6, Fig. 7, Fig.

8, Fig. 9 and Fig. 10 illustrate the infrared spectrum of compound No. 3, No. 3, No. 5, No. 6 and No. 3 of the present invention respectively.

In order to apply a compound of the invention as a herbicide, a suitable quantity of one or more of the compounds represented by the general formula (I) is generally mixed with an inert carrier or solvent to provide a herbicidal composition of a type suitable for use in ordinary agricultural applications such as a wettable powder, emulsifiable concentrate or a granulate.

Examples of a suitable solid carrier include talc, clay, kieselguhr and bentonite. Examples of a suitable liquid carrier include water, alcohol, benzene, xylene, kerosine, cyclohexane, cyclohexanone, dim ethyl formamide and mineral oil. Surface active agents or stabilizers may be incorporated into the composition as desired.

The resulting wettable powder or emulsifiable concentrate is diluted with water to a predetermined concentration to form aqueous dispersion or emulsion. In the case of a granulate the preparation is soil treated or soil incorporated prior to germination of weeds or is sprayed onto the foliar parts after the germination of weeds.

Furthermore, the herbicide of the present invention can be mixed with conventional fungicides, insecticides, acaricides, herbicides and plant-growth regulators. In order to save labour involved in further herbicidal treatments or to widen the weed spectrum of the plants effectively treated by the herbicide according to the invention, it is possible to incorporate other herbicides.

The compound according to the invention is generally incorporated in the herbicidal composition in a ratio of 100-0.5-0/0, preferably 50 to 1-0/0. When additional herbicides are also employed the ratio of the additional herbicide to the compound to the invention is in the range from 0.1 to 1 5.

The herbicidal composition can be applied, for example, in a quantity of from 0.25 to 10 by per hectane.

Examples of conventional herbicides suitable to be mixed with the compound of the invention includes the following: 2,4-dichlorophenoxy-acetic acid, the salts, esters and alkylamine salts thereof.

2-methyl-4-chlorophenoxy-acetic acid, the salts and esters thereof.

2-methyl-4-chlorophenoxy-butyric acid, the salts and esters thereof.

d, 1 -2-(4-chloro-o-tolyloxy)propionic acid, the salts and esters thereof.

octanoic acid-4-cyano-2,6-diiodophenyl.

2,4-dichlorophenyl-4'-nitrophenyl ether.

2,4,6-trichlorophenyl-4'-nitrophenyl either.

2,4-dichlorophenyl-3'-methoxy-4'-nitrophenyl ether.

methyl-3,4-dichlorocarbanilate.

lsopropyl-3-chlorocarbanilate.

S-4-chlorobenzyl diethyith iocarbamate.

4-nitrophenyl-3',5'-xylyl ether.

S-ethyl hexahydro-1 H-azepine-1-carbothioate.

3,4-dichloropropionic anilide.

2-chloro-2',6'-diethyl-N-(butoxymethyl)acetoanilide.

2-chlorn-2',6'-diethyl-N-(m-prnpoxyethyl)acetoanilide.

1-(a,-dimethylbenzyl)-3-p-tolyl urea.

2,4-bis(ethylamino)-6-mothylthio-1 3,5-triazine.

2-ethylamino-4-isopropylamino-6-methylthio- 1 ,3,5-triazine.

2,4-bis(isopropylamino)-6-methylthio- 1,3,5-triazine.

5-tert.-butyl-3-(2,4-dichloro-5-isopropoxyphenyl)- 1 ,3,4-oxadiazoline-2-on.

2,6-dichlorobenzonitrile.

2,6-dichlorothiobenzoamide.

2-amino-3-chloro-1 ,4-naphthoquinone.

2,4-dichlorophenyl-3'-carbomethoxy-4'-nitrophenyl ether.

N-p-chlorobenzyl-oxyphenyl-3,4,5,6-tetrahydrophthalimide.

2,4-d ichlorophenyl-3 '-ethoxyethoxyethoxy-4'-nitrophenyl ether.

N-( 1 -ethylpropyl)-2,6-dinitro-3,4-xylidine.

4-(2,4-dichlorobenzoyl)-l ,3-dimethyl-pyrazole-5-yl-p-toluene sulfonate.

4-(2,4-dichlorobenzoyl)- 1 ,3-dimethyl-5-(benzoylmethoxy)pyrazole.

o,o-diisopropyl-2-(benzene-sulfonamide)ethylene-dithio phosphate.

3,3'-dimethyl-4-methoxybenzophenone.

a-(2-naphthoxy)propion-anilide.

o-ethyl-o-(3-methyl-6-nitrophenyl)-N-sec.-butylphosphorothioamidate.

3-isopropyl-2,1 ,3-benzothiadiazinone-(4)2,2-dioxyde, the salts thereof.

S-(2-methyl-1 -piperidyl-carbonyl-methyl)-o,o-di-n-propyl-dithiophosphate.

Some of the above herbicides or specific combinations of two or more such herbicides provides a composition effective on various different weed spectra. To illustrate, if we select as typical compounds the herbicides of thiol carbamate group such as S-ethyl-N,N-hexamethylene thiol-carbamate and S-(4chlorobenzyl-N,N'-diethyl-thiol-carbamate which are generally used for the annihilation of barnyard grass or the other most harmful weeds in the paddy rice field, it is surprising to find that about a half or a third quantity of the dose necessary to annihilate them together with a compound of the present invention would wield sufficient herbicidal power and yet not adversely affect the rice plants.

The present invention is further illustrated in the following Examples.

Synthesis Example 1 4-[4-(4-Bromo-2-chloroanil ino)phenoxy]-2-pentenoic Acid Ethyl Ester 1.08 g of 4-(4-bromo-2-chloro-anilino) phenol and 0.97 g of 4-bromo-2-pentenoic acid ethyl ester dissolved together in 10 ml of acetone are added to 0.65 g of anhydrous potassium carbonate and the solution was heated for 10 hours with agitation under reflux. After reaction, the resulting KBr was filtered and the solvent was distilled off. The resulted residue was purified by silicagel chromatography using benzene as an eluent to obtain 1.13 g of oily product (73% yield). The product was recrystallized from hexane to yield the planar crystals of the title product having a melting point range 71--72 OC.

Synthesis Example 2 4-[4-(N-Methyl-2,4-dichloroanilino)phenoxy]-2-pentenoic Acid Ethyl Ester To 2.68 g of 4-(N-methyl-2,4-dichloroanilino) phenol and 2.48 g of bromo-2 pentenoic acid ethyl ester dissolved together in 20 ml of acetone was added 1.66 g of anhydrous potassium carbonate and the resulting solution was heated for 1 7 hours with agitation under reflux. After the same working-up as in Synthesis Example 1, 2.61 g (66% yield) of oily product of the title compound, orange in colour was obtained. n,25=1.5848.

Synthesis Example 3 4-[4-(2,4-Dichloroanilino)phenoxy]-2-pentenoic Acid Calcium Salt To the solution of 10.0 g of 4-[4-(2,4-dichloroanilino)phenoxy]-2-pentenoic acid ethyl ester in 50 ml of ethanol was added 40 ml of 1-N aqueous of sodium hydroxide, after the solution was stirred for 30 min. At 600C, ethanol was distilled off. To the resulting aqueous solution was added 40 ml of 1 N HCl-solution and the precipitate was extracted with ether. After the resulting ethereal solution was dried over anhydrous magnesium sulfate and ether was evaporated, 8.6 g of crystallized 4-[4-(2,4 dichloroanilino)phenoxy]-pentenoic acid was isolated.

To the solution of 2.0 g of 4-[4-(2,4-dichloroanilino)phenoxy]-2-pentenoic acid in a mixed solvent of 50 ml of ethanol with 5 ml of water was added 5.68 ml of 1 N sodium hydroxide solution. The resulting solution after being concentrated was treated with a solution of anhydrous calcium acetate, 0.45 g in 10 ml of water. The precipitated white crystals were filtered, washed, and dried under reduced pressure to yield the title compound (2.19 g).

The results of our elementary analysis were as follows: As for (C1Hr4Cl2NO3)2Ca . 2H2O: C H N Theoretical (%): 52.5 4.1 3.6 Found (%):- 52.9 3.9 3.7 Yield: 99%. The compound of this Example decomposes slowly changing in colour over 1 3O0C.

Synthesis Example 4 4-[4-(2,4-Dibromoanilino)phenoxy]-2-pentenoic Acid Ethyl Ester To 2.06 g of 4-(2,4-dibromoanilino)phenol and 1.61 g of 4-bromo-2-pentenoic acid ethyl ester dissolved together in 10 ml of acetone was added 1.08 g of anhydrous potassium carbonate and the mixture was heated for 14 hours with agitation under reflux. After the mixture was worked-up in a similar method as described in Synthesis Example 1,2.7 g of oily product (96% yield) of the title compound was obtained. n,25=1.6114.

Synthesis Example 5 4-[4-(2-nitro-4-trifluoromethylanilino)phenoxy]-2-pentenoic Acid Methyl Ester To 2.98 g of 4-(2-nitro-4-trifluoromethyianilino)phenol and 2.12 g of 4-bromo 2-pentenoic acid methyl ester dissolved together in 20 ml of acetone was added 1.66 g of anhydrous potassium carbonate and the solution was heated for 19 hours with agitation under reflux. After reaction, the produced potassium bromide was filtered, and the solvent was distilled off. The resulted residue was purified by silicagel column chromatography using benzene to obtain 2.74 g (67% yield) of dark-red viscous oily product of the title compound as eluent.

Synthesis Example 6 4-[4-(N-allyl-4-chloro-2-nitroanilino)phenoxy]-2-pentenoic Acid Ethyl Ester 3.26 g of 4-(N-allyl 4-chloro-2-nitroanilino)phenol and 2.22 g of 4-bromo-2-pentenoic acid ethyl ester were used. The process of Synthesis Example 1 is followed to yield 2.91 g of dark-red viscous oily product of the title compound (63% yield).

Synthesis Example 7 4-[4-(4-bromo-2-nitroanilino)phenoxy]-2-pentenoic Acid Butyl Ester 2.86 g of 4-(4-bromo 2-nitroanilino)phenol, 2.38 g of 4-bromo 2-pentenoic acid butyl ester and 1.52 g of anhydrous potassium carbonate were used. The process of Synthesis Ex. 1 was followed except that the mixture was heated for 6 hours to yield a dark-red viscous oily product 1.96 g of the title compound (46% yield).

Synthesis Example 8 4-[4-(2-nitro-4-trifluoromethylanilino)phenoxy]-2-pentenoic Acid Ethyl Ester To 677 mg of 4-(4-aminophenoxy)-2-pentenoic acid ethyl ester and 690 mg of 1 chloro-2 nitro-4 trifluoromethylbenzene dissolved together in isopropanol was added 303 mg of triethylamine, and the mixture was heated for 24 hours with agitation under reflux. After reaction, the solvent is distilled off and to the residue water and benzene were added. The resulting benzene layer is washed with water, dried over anhydrous magnesium sulfate, after the solvent has been distilled off. The residue was purified by silicagel column chromatography using benzene as an eluent and recrystallized from a mixed solvent of benzene with hexane to yield the title product 109 mg (38% yield) as orange crystals, melting point being 71-730C.

Now the examples concerning the preparation of the compound of the present invention will be described wherein the weed spectra and mixing proportion of the active ingredient and additives should not be limited within those as illustrated in these examples. "Part" shall denote "part by weight".

Preparation Example 1 Wettable Powder Twenty parts of Compound No. 3 of the present invention, 35 parts of kieselguhr, 40 parts of talc, 3 parts of sodium lignin-sulfonate and 2 parts of sodium dodecyl-benzene-sulfonate are mixed with crushing to form a wettable powder. Also, 20 parts of Compound No. 7 of the present invention, 30 parts of kieselguhr, 37 parts of talc, 8 parts of higher alcohol sulfate ester, 5 parts of white carbon are mixed with crushing to form a wettable powder.

Preparation Example 2 Emulsifiable Concentrate Twenty parts of Compound No. 3 of the present invention, 60 parts of xylene and 20 parts of polyoxyethylene stearate are homogeneously dissolved to form an emulsion. Also, 20 parts of Compound No. 1 0 of the present invention, 40 parts of dimethyl-formamide, 30 parts of xylene and 10 parts of polyoxyethylene-phenyl ether are homogeneously dissolved to form an emulsifiable concentrate.

Preparation Example 3 Granulate Five parts of Compound No. 3 of the present invention, 1 5 parts of bentonite, 52.5 parts of talc, 25 parts of clay, 2 parts of sodium lignin-sulfonate and 0.5 parts of sodium dodecyl-benzene-sulfonate are homogeneously mixed, added to water, agglomerated with an extruding granulator, dried and sieved to prepare a granular preparation. Also, 5 parts of Compound No. 9 of the present invention, 1 5 parts of bentonite, 52.5 parts of talc, 0.5 part of sodium dodecyl-benzene-sulfonate, 2 parts of sodium ligninsulfonate and 25 parts of clay are homogeneously mixed, added to water, pulverized with an extruding pulverizator, dried and sieved to form a granular preparation.

Herewith the herbicidal effect of the compound of the present invention is described by the following Experimental Examples.

Experimental Example 1 Testing for Barnyard Grass in the Direct Seeding System Under Submerged Condition After the paddy soil is laid in a Wagner pot of 1/5000 are, 20 grains of paddy rice (variety: Nihonbar6) together with 50 grains of barnyard grass seeds are sown. When the paddy rices and the barnyard grass seeds have sprouted and when they reach the two-leaf period, the water depth is controlled to 3 cm. The compound of the present invention is emulsified according to the process of Preparation Example 2 and diluted with water to a predetermined concentration. The diluted emulsion is applied evenly onto the surface of water. After 14 days, the herbicidal effect and the phytotoxicity effect of rice plants are investigated to obtain the results as found in Tables 2 and 3.

Table 2 Treatment test in the Germinating Stage

Treating quantity of active ingredient (kg/ha) Compound No. 1.0 0.5 0.25 1 Rice plant 77 95 100 barnyard grass 0 0 2 Rice plant 75 80 100 barnyard grass 0 0 0 3 Rice plant 80 98 102 barnyard grass I 0 0 0 4 Rice plant 1 75 80 100 barnyard grass 0 7 13 5 Rice plant 67 100 100 barnyard grass 0 0 0 Untreated | Rice plant 100 100 100 plot barnyard grass 100 100 100 Note: the values denote the ratio of living plant by weight to that for the untreated plot.

Table 3 Treatment in the two-lead stage

Treating Quantity of Active ingredient (kg/ha) Compound No. 2.0 1.0 0.5 1 Rice plant 85 93 100 barnyard gras 0 0 0 2 Rice plant 80 95 98 barnyard grass 0 0 0 3 Rice plant 101 102 102 barnyard grass 0 0 0 4 Rice plant 87 92 100 barnyard grass 0 0 0 5 Rice plant 90 100 108 barnyard grass 4 4 25 Untreated Rice plant 100 100 100 plot barnyard grass 100 100 100 Note: the values denote the ratio of living plant by weight to that for the untreated plot.

Experimental Example 2 Effect on Transplanted Paddy Rice Plant and Results of Phytotoxicity Tests After the paddy soil is laid in a Wagner pot of 1/5000 are, 50 grains of barnyard grass are sown.

Further a root with two stems per pot of paddy rice plant is transplanted and maintained under a submerged condition of 3 cm. When the barnyard grass has reached the two-leaf stage, the nmulsifiable concentrate of compound of the present invention applied in Experimental Example 1, after diluted with a predetermined quantity of water, is applied evenly onto the surface with water. 21 Days after the chemical treatment, the herbicidai effect and the toxicity result of rice plants are investigated to obtain the results of Table 4.

Table 4

Treating quantity of active ingredient {kg/haJ Compound No. 6.0 4.0 2.0 1 Rice plant 98 100 101 barnyard grass 0 0 0 2 Rice plant 95 100 105 barnyard grass 0 0 0 3 Rice plant 102 103 103 barnyard grass 0 0 0 4 Rice plant 102 103 103 barnyard 0 0 0 5 Rice plant 102 102 105 barnyard grass 0 0 0 Untreated Rice plant plot barnyard grass Note: the values denote the ratio of living plant by weight to that for the untreated plot.

Experimental Example 3 Soil Treatment Test Seeds of barnyard grass, foxtail, crabgrass, soyabean, sugar beet and potato are sown in the pots of 250 cm3 filled with the field soil and are covered with soil. Each sample of the compounds is diluted with water to the predetermined concentration. This diluted liquor is evenly sprayed over the soil at a rate of 1000 lit/ha. In 20 days after the chemical treatment, the weed left is weighed to compare the untreated plot (survival ratio).

The obtained results are shown in Table 5.

Table 5

Active Survial ratio % Compound ingredient barnyard No. kg/ha grass Foxtail Crabgras soybean sugar beet Potato 6 1.0 0 0 0 100 100 100 2.0 0 0 0 100 100 100 7 1.0 0 0 0 100 100 100 2.0 0 0 0 100 100 100 8 1.0 0 0 0 100 100 100 2.0 0 0 0 100 100 100 9 1.0 0 0 0 100 100 100 2.0 0 0 0 100 100 100 10 1.0 0 0 0 100 100 100 2.0 0 0 0 100 100 100 11 1.0 0 0 0 100 100 100 2.0 0 0 0 100 100 100 12 1.0 0 0 0 100 100 100 2.0 O 0 0 0 100 100 100 13 1.0 | 0 0 0 100 | 100 100 2.0 O O O 100 100 100 Untreated - 100 100 100 100 100 100 plot - | 100 100 100 100 100 100 Experimental Example 4 Seeds of barnyard grass, foxtail, crabgrass, soyabean, sugar beet and potato are sown in the pots of 250 cm3 filled with the field soil and are covered with soil to germinate and grow in the green house.

When the soya plants have reached the two-leaf stage, each sample of the compound is diluted with water to a predetermined concentration. This diluted liquor is evenly sprayed over the soil at a rate of 1000 lit./ha. 20 Days after the chemical treatment, the remaining weeds are weighed to compare the proportion to the quantity of weeds in the untreated plot (survival ratio). The obtained results are shown in Table 6.

Table 6

Active Survival ratio % Compound ingredient barnyard No. kg/ha grass Foxtail Crabgrass soybean sugar beet Potato 6 2.0 0 0 0 100 100 100 7 2.0 0 0 0 100 100 100 8 2.0 0 0 0 100 100 100 9 2.0 0 0 0 100 100 100 10 2.0 0 0 0 100 100 100 11 2.0 0 0 0 100 100 100 12 2.0 0 0 0 100 100 100 13 2.0 0 0 0 100 100 100 Untreated - 100 100 100 100 100 100 plot Effects of the present invention will be explained more particularly in Experimental Example 5, and Table 7 and 8.

Experimental Example 5 Test of the Compound of the Present Invention Mixed with a Herbicide of the Thiol-carbamate Group Such as Molinate and Saturn After the paddy soil is laid in a Wagner pot of 1/5000 are, 20 grains of paddy rice (nomenclature being Nihonbaré) together with 20 grains of barnyard grass seeds are sown. When the plants have reached the 1 .5-leaf state, the water depth is controlled to 2 cm and the compound of the present invention in the form of an emulsifiable concentrate according to Experimental Example 2 and diluted with water to a predetermined concentration, is applied evenly. 14 Days after the chemical treatment, the herbicidal effect and the phytotoxicity result of rice plants are investigated to obtain the results of Tables 7 and 8.

Table 7 Synergistic Effect of Molinate or S-ethyl-N,N-hexamethylene-thiolcarbamate

Concentration of Molinate (kg/ha) 0.0625 0.125 0.25 0.50 1.00 2.00 0 Its concentration Compound Barnyard Barnyard Barnyard Barnyard Barnyard Barnyard Barnyard of the invention grass Rice grass Rice grass Rice grass Rice grass Rice grass Rice grass Rice 0.0625 0 0 1.5 0 0 0 0.125 1.5 0 2.5 0 3.5 0 0.5 0 No. 3 0.25 0 3.5 0 4.5 0 5.0 0 1.0 0 0.50 5.0 0 5.0 0 5.0 0 5.0 0 5.0. 0 3.0 0 1.00 5.0 0.5 0 0 0 0.5 0 1.0 0 2.5 0 3.5 0 5.0 1.0 Note: "0-5" denote "none-perfect kill".

Table 8 Synergistic effect of Saturn or S-(4-chlorobenzyl)-N,N-diethyl-thiocarbamate

Concentration of Saturn (kg/ha) 0.0625 0.125 0.25 0.50 1.00 2.00 0 Its concentration Compound Barnyard Barnyard Barnyard Barnyard Barnyard Barnyard Barnyard of the Invention grass Rice grass Rice grass Rice grass Rice grass Rice grass Rice grass Rice 0.0625 0 0 1.5 0 0 0 0.125 1.5 0 2.5 0 3.5 0 0.5 0 No. 3 0.25 0 3.5 0 4.5 0 5.0 0 1.0 0 0.50 5.0 0 5.0 0 5.0 0 5.0 0 5.0 0 3.0 0 1.00 5.0 0.5 0 0 0 0.5 0 1.0 0 2.0 0 3.5 0 5.0 0 Note: "0-5" denote "none-perfect kill".

Claims (26)

Claims

1. 4-[4-(Anilino)phenoxy]-2-pentenoic acid or its derivatives represented by the general formula (1):

wherein R, represents a chlorine or bromine atom or a trifluoromethyl radical; R2 represents a chlorine or bromine atom or a nitro radical; R3 represents a hydrogen atom or a lower alkyl or lower alkenyl radical; and R4 represents a hydrogen atom, a lower alkyl radical, an alkali metal cation, an aikaline earth metal cation or an amino cation.

2. Compounds of the general formula (ill):

wherein R1, R2, R3 and R4 are as defined in claim 1.

3. 4-[4-(2,4-Dichloro-anilino)-phenoxy]-2-pentenoic acid methyl] ester.

4. 4-[4-(2,4-Dichloro-anilino)-phenoxy]-2-pentenoic acid butyl ester.

5. 4-[4-(2,4-Dichloro-anilino)-phenoxy]-2-pentenoic acid ethyl ester

6. 4-[4-(N-Methyl-2,4-dichloroanilino)-phenoxy]-2-pentenoic acid ethyl ester.

7. 4-[4-Bromo-2-chloroanilino)-phenoxy]-2-pentenoic acid ethyl ester.

8.4-[4-(2-Nitro-4-trifluoromethyl-anilino)phenoxy]-2-pentenoic acid methyl ester.

9. 4-[4-(4-Trifluoromethyl-2-nitroanilino)-phenoxy]-2-pentenoic acid ethyl ester.

1 0. 4-[4-(4-Trifluoromethyl-2-nitroanilino)-phenoxy]-2-pentenoic acid butyl ester.

11. 4-[4-(4-Chloro-2-nitroanilino)-phenoxyj-2-pentenoic acid methyl ester.

12. 4-[4-(4-Chloro-2-nitroanilino)-phenoxy]-2-pentenoic acid ethyl ester.

1 3. 4-[4-(N-Allyl-4-chloro-2-nitroanilino)-phenoxy]-2-pentenoic acid ethyl ester.

1 4. 4-[4-(4-Bromo-2-nitroan ilino)-phenoxyj-2-pentenoic acid ethyl ester.

1 5. 4-[4-(4-Bromo-2-nitroanilino)phenoxy]-2-pentenoic acid butyl ester.

1 6. A compound of general formula (I) as defined in claim 1 substantially as herein described with reference to the properties of specific compounds listed herein, the Synthesis Examples 1 to 8 and the accompanying drawings Figures 1 to 10.

1 7. A herbicidal composition comprising as active ingredient at least one compound of general formula (I) as defined in claim 1 together with a carrier or solvent therefor.

1 8. A herbicidal composition according to claim 1 7 comprising a herbicide of the carbamate group, as another active ingredient.

19. A herbicidal composition according to claim 18, wherein the herbicide of the carbamate group is S-ethyl-N,N-hexamethylene-thiol-carbamate and/or S-(4-chlorobenzyl)-N,N-diethyl-thiolcarbamate.

20. A herbicidal composition according to claim 17 substantially as herein described with reference to any of the Preparation Examples 1 to 3.

21. A method for preparing 4[4-anilino)phenoxy]-2-pentenoic acid or a derivative thereof represented by the general formula (I) as defined in claim 1 which comprises reacting a compound represented the general formula (A)

with a compound represented by the general formula (B)

wherein Rr, R2, R3, and RA are as defined for formula (I) and Hal represents a halogen atom.

22. A method for preparing 4-[4-(anilino)phenoxy]-2-pentenoic acid or a derivative represented by the general formula (I) as defined in claim 1 which comprises reacting a compound represented by the general formula (C)

with a compound represented by the general formula (D)

wherein R, R2, R3 and R4 are as defined for formula (I) and Hal represents a halogen atom.

23. A method for preparing 4-[4(anilino)phenoxy]-2-pentenoic acid or a derivative thereof represented by the general formula (I) as defined in claim 1, which comprises reacting a compound represented by the general formula (E)

with a compound represented by the general formula (F) Hal-R (F) wherein RX, R2, R3 and R4 are as defined for formula (I), and Hal represents a halogen atom.

24. A method for the preparation of a compound of general formula (I) as defined in claim 1 substantially as herein described with reference to any of the synthesis Examples 1 to 8.

25. A method of combating weeds which comprises applying to the weeds or to their environment or potential environment an effective amount of a compound of general formula (I) as defined in claim 1.

26. A method according to claim 25 substantially as herein described with reference to any of the specific Experimental Examples 1 to 5.