DE3900353A1 - 5-(N-3,4,5,6-tetrahydrophthalimido)cinnamamides - Google Patents

Abstract

5-(N-3,4,5,6-tetrahydrophthalimido)cinnamamides of the formula I <IMAGE> in which the substituents have the following meanings: Y is chlorine, bromine, or a C1-C4-alkyl group and R<1> and R<2> are hydrogen, a C1-C4-alkyl group or together with the N atom a 5- or 6-membered aliphatic ring whose carbon chain can be interrupted by an oxygen atom are suitable as herbicides.f

Description

The present invention relates to 5- (N-3,4,5,6-tetrahydrophthalimido) - cinnamamides of the formula I

in which the substituents have the following meanings:
Y is chlorine, bromine or a C₁-C₄-alkyl group
R¹ and R² are hydrogen, C₁-C₄-alkyl groups or together with the N-atom to form a 5- or 6-membered aliphatic ring whose carbon chain may be interrupted by an oxygen atom.

Furthermore, the invention relates to processes for the preparation of these Compounds and their use as herbicides.

Japanese Laid-Open Patent Kokai 27,962 / 1986 discloses esters and amides of structure I ',

in the A, for example -NHCH₃, -N (CH₃) ₂ or -N (CH₂CH = CH₂) ₂ and Z Hydrogen or fluorine means.

Furthermore, from EP-A-2 40 659 a general formula is known which the the above-mentioned compounds I.

The invention was based on the object, especially active herbicides Provide connections.

It has now been found that the above-defined 5- (N-3,4,5,6-tetrahydrophthalimido) - cinnamic acid amides of the formula I is a good herbicidal Possess effectiveness.  

In addition, methods have been found for preparing the compounds I, and further it has been found that the compounds of the invention especially in the after-run process, a beneficial herbicidal action and are selective against a range of crops and themselves can be used successfully accordingly.

The compounds I are obtained, for example, by reacting 3,4,5,6-tetra hydrophthalic anhydride with the equivalent amount of a 5-amino cinnamon acid amides of the formula V in an inert organic solvent implements.

As a solvent z. B. lower alkanoic acids such as acetic acid, propionic acid and isobutyric acid, as well as the ester of these acids, such as ethyl acetate, higher boiling hydrocarbons such as toluene and xylene and / or dimethylformamide. The reaction usually takes place at temperatures between 25 ° C and the boiling point of the respective reaction mixture, preferably between 70 and 140 ° C. When working in an aprotic Solvent, it is advisable to remove the water continuously.

The aniline derivatives of the formula V are in a conventional manner from the corresponding nitrophenyl derivatives IV either by reduction with inorganic Compounds such as stannous salts or iron or, if Y is not Bromine or chlorine means by catalytic hydrogenation on metal contacts such as Raney nickel, palladium and platinum available.

The required nitrophenyl derivatives can be prepared in various ways, z. B .:

• a) if Y is C₁-C₄-alkyl group by reacting a corresponding nitrocinnamic acid II (EP-A-2 40 659) in an inert organic solvent which may contain water in the presence of a base with an amine III. The reaction temperature is generally from -15 to 50 ° C, preferably -10 to 40 ° C. Suitable solvents are, for example, tetrahydrofuran, dioxane, 1,2-dimethoxyethane and acetonitrile.
  In addition to inorganic bases, for example, the amine itself in excess or tertiary amines such as triethylamine, diisopropylethylamine, N, N-dimethyl-p-aminopyridine, N-methylpyrrolidine, N, N, N ', N'-tetramethylethylenediamine, 1.5- Diazabicyclo (4.3.0) non-5-ene and 1,8-diazabicyclo (5.4.0) undec-7-ene.
  Preferably, this reaction is carried out in tetrahydrofuran or dioxane, wherein the amine can be added as an aqueous solution or as a solution in one of the abovementioned ethers, wherein the amine itself or triethylamine are used as the base.
• b) if Y is chlorine or bromine (Hal), by reacting a nitrocinamide of the formula IVb in an inert organic solvent with the appropriate halogen. The reaction is usually carried out at temperatures of 0 to 60 ° C, preferably 15 to 40 ° C.
  Suitable solvents include methylene chloride, chloroform, carbon tetrachloride, 1,1,1-trichloroethane and chlorobenzene, with methylene chloride, chloroform and 1,1,1-trichloroethane being preferred.

The compounds of the formula I in which R¹ and / or R² require a large amount of space but you also get z. From the corresponding 5- (N-3,4,5,6- Tetrahydrophthalimido) cinnamic acid chlorides VI by reaction with a Amine of formula III. If R¹ and / or R² only small space requirement (steric hindrance) may possess as side reaction ring opening of the occur cyclic imide.

For example:

The reaction is usually in an inert manner in a conventional manner organic solvents in the presence of a base at temperatures of -15 to 50 ° C, preferably at -5 to 30 ° C performed.

Suitable solvents for this reaction are u. a. hydrocarbons such as toluene and xylene, lower esters of alkanoic acids such as ethyl acetate and ethers such as tetrahydrofuran, dioxane and diisopropyl ether.

Suitable auxiliary bases are in addition to inorganic bases z. B. tertiary amines such as the above, as well as pyridine, collidine and methylpiperidine, are preferred however, triethylamine.

A synthesis of cinnamic acid chloride VI is described in EP-A-2 40 659.

With regard to the intended use of the compounds I come the following radicals are suitable as substituents:

Y, in addition to chlorine and bromine, denotes alkyl groups, such as methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl and the tert-butyl group, wherein the methyl and the ethyl groups and chlorine and bromine are preferred become.

The radicals R¹ and R² can independently of one another denote hydrogen or alkyl groups, as defined under Y, mean. In addition, R¹ and R² can also together with the N atom, a 5- or 6-membered cycloaliphatic Ring form, whose carbon chain interrupted by an oxygen atom can be.  

Examples of such cyclic amides are pyrrolidides, isoxazolidides, Piperidides and morpholides.

Examples of very active compounds I are in the following Table 1 listed.  

Table 1

The 5- (N-3,4,5,6-tetrahydrophthalimido) cinnamic acid derivatives I or they herbicidal agents containing, for example, in the form of directly sprayable solutions, powders, suspensions, even high percentage aqueous, oily or other suspensions or dispersions, emulsions, Oil dispersions, pastes, dusts, litter or granules applied by spraying, atomizing, dusting, scattering or pouring become. The forms of application depend on the intended use; you should in each case as possible the finest distribution of the invention Ensure active ingredients.

The compounds I are generally suitable for the preparation of direct sprayable solutions, emulsions, pastes or oil dispersions Mineral oil fractions of medium to high boiling point, such as kerosene or Diesel oil, coal tar oils and vegetable or animal oils Origin, aliphatic, cyclic and aromatic hydrocarbons, z. Toluene, xylene, paraffin, tetrahydronaphthalene, alkylated naphthalenes or their derivatives, methanol, ethanol, propanol, butanol, cyclohexanol, Cyclohexanone, chlorobenzene, isophorone or strongly polar solvents, such as N, N-dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone or water.

Aqueous application forms can be prepared from emulsion concentrates, dispersions, Pastes, wettable powders or water-dispersible granules by addition to be prepared from water. For the preparation of emulsions, pastes or oil dispersions may be the substrates as such or in an oil or Solvent dissolved by means of wetting, adhesion, dispersing or emulsifying agent be homogenized in water. It can also be more effective Substance, wetting, adhesion, dispersing or emulsifying agent and possibly Solvent or oil existing concentrates are produced, the Dilution with water are suitable.

As surface-active substances are the alkali, alkaline earth, ammonium salts of aromatic sulfonic acids, e.g. As lignin, phenol, naphthalene and dibutylnaphthalenesulfonic acid, as well as fatty acids, alkyl and alkylaryl sulfonates, Alkyl, lauryl ether and fatty alcohol sulfates, as well as salts sulfated hexa-, hepta- and octadecanols, as well as fatty alcohol glycol ethers, Condensation products of sulfonated naphthalene and its Derivatives with formaldehyde, condensation products of naphthalene or the Naphthalenesulfonic acids with phenol and formaldehyde, polyoxyethylene octylphenol ether, ethoxylated isooctyl, octyl or nonylphenol, alkylphenol, Tributylphenyl polyglycol ethers, alkylaryl polyether alcohols, isotridecyl alcohol, Fatty alcohol ethylene oxide condensates, ethoxylated castor oil, Polyoxyethylene alkyl ether or polyoxypropylene, lauryl alcohol polyglycol ether acetate, Sorbitol esters, lignin-sulphite liquors or methylcellulose into consideration.  

Powders, litter and dusts can be mixed or mixed Grinding the active substances with a solid carrier become.

Granules, for. B. coated, impregnated and homogeneous granules be prepared by binding the active compounds to solid carriers. Solid carriers are mineral earths such as silica gel, silicas, silica gels, Silicates, talc, kaolin, limestone, lime, chalk, bolus, loess, clay, Dolomite, diatomaceous earth, calcium and magnesium sulphate, magnesium oxide, milled plastics, fertilizers, such as ammonium sulfate, ammonium phosphate, Ammonium nitrate, ureas and vegetable products, such as cereal flour, Bark, wood and nutshell flour, cellulose powder or other solid Carriers.

The formulations contain between 0.1 and 95% by weight, preferably between 0.5 and 90 wt .-%, active ingredient.

Examples of formulations are:

• I. 90 parts by weight of compound no. 1.001 are mixed with 10 parts by weight of N-methyl- a- pyrrolidone and a solution is obtained which is suitable for use in the form of very small drops.
• II. 20 parts by weight of compound no. 1,027 are in one Mixture dissolved, consisting of 80 parts by weight of xylene, 10 parts by weight of the adduct of 8 to 10 moles of ethylene oxide 1 mole of oleic acid N-monoethanolamide, 5 parts by weight of calcium salt of Dodecylbenzenesulfonic acid and 5 parts by weight of the adduct of 40 moles of ethylene oxide to 1 mole of castor oil. By pouring and finely distributing the solution in 100,000 parts by weight of water gives an aqueous dispersion, containing 0.02% by weight of the active substance.
• III. 20 parts by weight of compound no. 1,016 are in one Mixture dissolved from 40 parts by weight of cyclohexanone, 30 parts by weight of isobutanol, 20 parts by weight of the addition product from 7 moles of ethylene oxide to 1 mole of isooctylphenol and 10 parts by weight of the adduct of 40 moles of ethylene oxide to 1 mole of castor oil. By pouring and fine distribution The solution is obtained in 100 000 parts by weight of water aqueous dispersion containing 0.02 wt .-% of the active ingredient.  
• IV. 20 parts by weight of the active ingredient No. 1.005 are in one Mixture dissolved, consisting of 25 parts by weight of cyclohexanone, 65 parts by weight of a mineral oil fraction of boiling point 210 to 280 ° C and 10 parts by weight of the adduct of 40 mol Ethylene oxide to 1 mole of castor oil. By pouring and Fine distribution of the solution in 100 000 parts by weight of water to obtain an aqueous dispersion containing 0.02 wt .-% of the active ingredient contains.
• V. 20 parts by weight of compound no. 1,010 are mixed well with 3 parts by weight of the sodium salt of diisobutylnaphthalene- α- sulfonic acid, 17 parts by weight of the sodium salt of a lignosulfonic acid from a sulfite waste liquor and 60 parts by weight of powdered silica gel and ground in a hammer mill. By finely distributing the mixture in 20,000 parts by weight of water to obtain a spray mixture containing 0.1 wt .-% of the active ingredient.
• VI. 3 parts by weight of the active ingredient No. 1,021 are 97 parts by weight finely divided kaolin mixed. You get that way a dust containing 3% by weight of the active ingredient.
• VII. 30 parts by weight of the active ingredient No. 1.017 are with a Mixture of 92 parts by weight of powdered silica gel and 8 parts by weight of paraffin oil, which is on the surface of this Silica gel was sprayed, intimately mixed. You get up this way, a preparation of the active substance with good adhesion.
• VIII. 20 parts by weight of the active ingredient No. 1,015 are with 2 parts by weight Calcium salt of dodecylbenzenesulfonic acid, 8 parts by weight Fatty alcohol polyglycol ether, 2 parts by weight of sodium salt of a Phenol-urea-formaldehyde condensates and 68 parts by weight a paraffinic mineral oil intimately mixed. You get one stable oily dispersion.

The application of the herbicidal compositions or of the active ingredients can be carried out in the pre-emergence phase. or post-emergence. Are the active ingredients for certain Crop plants less compatible, so may application techniques be applied, in which the herbicidal agents using the sprayers so sprayed, sat the leaves of the delicate crops if possible, are not taken while the active ingredients on the leaves underneath growing unwanted plants or the uncovered floor area (post-directed, lay-by).  

The application rates of active ingredient are depending on the target, season, Target plants and growth stage 0.001 to 3.0, preferably 0.01 up to 1.0 kg / ha.

In view of the versatility of the application methods, the Compounds according to the invention or agents containing them in one further number of crops for the removal of unwanted plants be used. For example, the following cultures may be considered:

Botanical name German name Allium cepa onion Pineapple comosus pineapple Arachis hypogaea Peanut Asparagus officinalis asparagus Avena sativa oats Beta vulgaris spp. altissima sugar beet Beta vulgaris spp. rapa mangel Beta vulgaris spp. esculenta Red beet Brassica napus var. Napus rape Brassica napus var. Napobrassica Turnip Brassica napus var. Rapa White turnip Brassica rapa var. Silvestris beets Camellia sinensis Teestrauch Carthamus tinctorius Safflower safflower Carya illinoinensis Pecan Citrus limon lemon Citrus maxima grapefruit Citrus reticulata tangerine Citrus sinensis Orange, orange Coffea arabica (Coffea canephora, Coffea liberica) coffee Cucumis melo melon Cucumis sativus cucumber Cynodon dactylon Bermuda grass Daucus carota carrot Elaeis guineensis oil palm Fragaria vesca strawberry Glycine max Soybean Gossypium hirsutum (Gossypium arboreum, Gossypium herbaceum, Gossypium vitifolium cotton Helianthus annuus sunflower Helianthus tuberosus Jerusalem artichokes Hevea brasiliensis Para rubber tree Hordeum vulgare barley Humulus lupulus hop Ipomoea batatas sweet potatoes Juglans regia walnut tree Lactuca sativa lettuce Lens culinaris lens Linum usitatissimum flax Lycopersicon lycopersicum tomato Malus spp. Apple Manihot esculenta manioc Medicago sativa alfalfa Mentha piperita peppermint Musa spp. Fruit and flour banana Nicotiana tabacum (N. rustica) tobacco Olea europaea olive tree Oryza sativa rice Panicum miliaceum Rispenhirse Phaseolus lunatus butterbean Phaseolus mungo Erdbohne Phaseolus vulgaris bush beans Pennisetum glaucum Perl or cattail millet Petroselinum crispum spp. tuberosum root parsley Picea abies Rotfichte Abies alba white fir Pinus spp. pine Pisum sativum garden pea Prunus avium sweet cherry Prunus domestica plum Prunus dulcis almond Prunus persica peach Pyrus communis pear Ribes sylvestre Red currant Ribes uva-crispa gooseberry Ricinus communis castor-oil plant Saccharum officinarum sugarcane Secale cereal rye Sesamum indicum sesame Solanum tuberosum potato Sorghum bicolor (see vulgare) sorghum Sorghum dochna sweet sorghum Spinacia oleracea spinach Theobroma cacao cacao Trifolium pratense Red clover Triticum aestivum wheat Triticum durum durum wheat Vaccinium corymbosum Cultivated blueberry Vaccinium vitis-idaea Preißelbeere Vicia faba horse beans Vigna sinensis (V. unguiculata) cowpea Vitis vinifera grapevine Zea mays Corn

To broaden the spectrum of action and to achieve synergistic Effects can be the 5- (N-3,4,5,6-tetrahydrophthalimido) cinnamic acid amides of Formula I with numerous representatives of other herbicidal or growth-regulating Active ingredient groups are mixed and applied together. For example come as a mixing partner Diazines, 4H-3,1-Benzoxazine derivatives, Benzothiadiazinones, 2,6-dinitroanilines, N-phenylcarbamates, Thiolcarbamates, halocarboxylic acids, triazines, amides, ureas, diphenyl ethers, Triazinones, uracils, benzofuran derivatives, cyclohexane-1,3-dione derivatives, Quinolinecarboxylic acid derivatives and others.

In addition, it may be useful to use the novel compounds of formula I. alone or in combination with other herbicides also with others Mixed pesticides apply together, for example, with Agents for combating pests or phytopathogenic fungi or Bacteria. Also of interest is the miscibility with mineral salt solutions, which used for the elimination of nutritional and trace element deficiencies become. It may also contain non-phytotoxic oils and oil concentrates be added.

The instructions given in the Synthesis Examples below were obtained with appropriate modification of the starting compounds for recovery further compounds I used. The compounds thus obtained are listed in Table 1 below with physical data.

Example 1 Preparation of 5- (N-3,4,5,6-tetrahydrophthalimidoimido) -2-chloro- α -bromocinnamic acid N, N-dimethylamide 1.1 2-Chloro-5-nitrocinnamic acid N, N-dimethylamide

A solution of 26 ml (0.52 mol) of 40% aqueous dimethylamine in 100 ml Tetrahydrofuran was added to 0-5 ° C with 32.0 g (0.13 mol) 2-chloro-5-  Nitrozimtsäurechlorid in 100 ml of tetrahydrofuran and this Mixture then stirred for 4 hours at 25 ° C. After removing the Solvent, the residue obtained was dissolved in 150 ml of ethyl acetate, washed and dried. After removal of the solvent at reduced pressure gave 18.2 g of 55% d. Th.) Of the compound sought, Mp 136-137 ° C.

1.2 2-Chloro-5-nitro- α -bromo-cinnamic acid N, N-dimethylamide

A solution of 17 g (67 mol) of the compound obtained in 1.1 in 100 ml Methylene chloride was heated at 25 ° C with 10.7 g (67 mmol) of bromine in 10 ml Methylene chloride added. After one hour at 40 ° C, another 0.5 ml Bromine added and this mixture stirred for a further hour at 40 ° C. After removal of the solvent and trituration with petroleum ether 27.6 g of the dibromo adduct (mp 212-213 ° C), which in 150 ml of methanol dissolved and at 25 ° C dropwise with a solution of 12 g (67 mmol) 30% NaOCH₃ in 80 ml of methanol was added. After 2 hours at 65 ° C, After cooling and removal of the methanol, the residue was stirred with water. then extracted with ethyl acetate. From the organic phase received 17.6 g (79%) of the desired nitroamide, which without further purification was converted to the aniline derivative.

1.3 2-Chloro-5-amino- α- bromo-cinnamic acid N, N-dimethylamide

A suspension of 13.9 g (0.248 mol) of iron powder in 150 ml of methanol and 100 ml of glacial acetic acid was added at 60 ° C in portions with 16.6 g (49 mmol) of 1.2 added nitro compound and then this mixture Heated to 80 ° C for 2 hours. It was allowed to cool, gave the reaction mixture in 1 liter of water and removed the solid components. The aqueous phase was extracted twice with ethyl acetate. From the organic Phase, 14.9 g (100%) of an oil were obtained without further purification was processed.

1.4 Reaction with tetrahydrophthalic anhydride to the title compound

14.9 g (49 mmol) of the aniline derivative obtained in 1.3 and 7.5 g (49 mmol) tetrahydrophthalic anhydride were dissolved in 80 ml of glacial acetic acid and this solution heated to 100 ° C for three hours. After cooling it was The reaction mixture was added to water and extracted with ethyl acetate. The organic phase was separated, dried and concentrated. One received 10 g of an oil (52% of theory) which crystallized later, mp 162-163 ° C (Part No. 1.018).  

example 2 Preparation of 5- (N-3,4,5,6-tetrahydrophthalimidoimido) -2-chloro- α -methylcinnamic acid N-methylamide 2.1 2-Chloro-5-nitro- α- methylcinnamic acid N-methylamide

A solution of 34.8 ml (0.4 mol) of methylamine (40% aqueous solution) in 100 ml of tetrahydrofuran was at 5 to 10 ° C with 26 g (0.1 mol) of 2-chloro-5-nitro- α Methyl cinnamic acid chloride in 100 ml of tetrahydrofuran. After stirring for 4 hours, the solvent was removed and the residue obtained was added to 100 ml of water. The resulting solid was isolated and dried. This gave 21.7 g (85% of theory) of a solid having mp: 146-147 ° C.

2.2 2-Chloro-5-amino- α- methylcinnamic acid N-methylamide

Analogously to 1.3, 21.7 g (85 mmol) of the product obtained under 2.1 were obtained Nitro compound in 150 ml of methanol and 100 ml of glacial acetic acid with 22.3 g (0.4 mol) iron powder 19.4 g (100%) of an oil, which without further purification was used at 2.3.

2.3 Reaction with tetrahydrophthalic anhydride

Analogously to 1.4, 19.4 g (85 mmol) of the product obtained at 2.2 were obtained Aniline derivative in 100 ml of glacial acetic acid with 12.9 g (85 mmol) of tetrahydrophthalic acid acid anhydride 14.7 g (48% of theory) of a solid with mp: 179 to 180 ° C. (Part No. 1,026).

example 3 Preparation of 5- (N-3,4,5,6-tetrahydrophthalimido) -2-chloro- α -methylcinnamic acid morpholide 3.1 2-chloro-5-nitro- α- methyl-cinnamic acid morpholide

A solution of 13 g (0.05 mol) of 2-chloro-5-nitro- α- methyl-cinnamic acid chloride in 100 ml of tetrahydrofuran was added at 5-10 ° C with 8.7 g (0.1 mol) of morpholine. 111.4 g (74%) of the desired product, mp 120-121 ° C., were obtained in analogy to the conditions described in 2.1.

3.2 2-Chloro-5-amino- α- methyl-cinnamic acid morpholide

Analogously to 1.3, 11.2 g (0.15 mol) of the product obtained in 3.1 were obtained Nitro compound with 8.4 g (0.15 mol) of iron powder in 70 ml of glacial acetic acid and 100 ml of methanol 10.9 g of the desired aniline derivative.

3.3 5- (N-3,4,5,6-tetrahydrophthalimido) -2-chloro- α -methylcinnamic acid morpholide

Analogously to 1.4, 10.1 g (36 mmol) of the product obtained at 3.2 were obtained Aniline derivative in 75 ml glacial acetic acid with 5.5 g (36 mmol) tetrahydrophthal acid anhydride 14.7 g (about 99%) of a resin with mp 110-114 ° C (code No. 1,017).

example 4 Preparation of 5- (N-3,4,5,6-tetrahydrophthalimido) -2-chloro- α -methylcinnamic acid tert-butylamide

A cooled to 0 ° C solution of 10.9 g (30 mmol) of 2-chloro-5-tetrahydrophthalimido- α- methylcinnamic acid chloride in 150 ml of ethyl acetate was treated with 7.3 g (0.1 mol) of tert-butylamine in 30 ml of ethyl acetate added. After stirring for 1 hour at 25 ° C, the solvent was removed, the residue was treated with 100 ml of 5% hydrochloric acid and the precipitate formed was isolated. This gave 6.5 g (54%) of the title compound. Mp 141-142 ° C (compound no. 1.006).

Table 12

applications

The effect of 5- (N-3,4,5,6-tetrahydrophthalimido) -cinnamic acid amides I on the growth of the test plants was achieved by the following greenhouse experiments demonstrate.  

As culture vessels serve plastic flower pots with 300 cm³ content and loamy Sand with about 3.0% humus as substrate. The seeds of the test plants are sown separately by species.

For postemergence treatment, either seeded directly or in or the same plants grown or selected dressed as seedlings separated and few days before treatment in transplanted the test vessels.

Depending on the growth form, the test plants are at a stature height of 3 to 15 cm then with the suspended in water as a distribution agent or emulsified active ingredients that are sprayed through finely distributing nozzles are going to be treated. The application rate for postemergence treatment is 0.06 kg / ha a. S. (active substance).

The test vessels are placed in the greenhouse, with heat-loving Species warmer areas (20 to 35 ° C) and more temperate for those Climates 10 to 20 ° C are preferred. The trial period extends over 2 to 4 weeks. During this time, the plants are maintained and their response to each treatment is evaluated.

The rating is based on a scale from 0 to 100. 100 means no Rising of the plants or complete destruction of at least the above ground Parts and 0 no damage or normal growth.

The plants used in the greenhouse experiments are precipitated following types together:

Latin name German name Abutilon theophrasti Chinese hemp Amaranthus retroflexus Bent-back foxtail Chrysanthemum corinarium Crown Wucherblume Galium aparine cleavers Solanum nigrum Black nightshade Triticum aestivum spring wheat

With 0.06 kg a. S. used postemergence, can be with the Examples 1023 and 1024 broadleaf unwanted plants look good fight. Example 1015 fought with 0.06 kg / ha a. S. im Postemergence, very good broadleaf unwanted plants at simultaneous crop plant compatibility.

Claims (8)

1. 5- (N-3,4,5,6-tetrahydrophthalimido) -cinnamic acid amides of the formula I. in which the substituents have the following meanings:
Y is chlorine, bromine or a C₁-C₄-alkyl group
R¹ and R² are hydrogen, a C₁-C₄-alkyl groups or together with the N-atom to form a 5- or 6-membered aliphatic ring whose carbon chain may be interrupted by an oxygen atom. 2. A process for the preparation of the compounds I according to claim 1, wherein Y is C₁-C₄-alkyl, characterized in that a nitrocinnamyl chloride of the formula II in a manner known per se in an inert organic solvent in the presence of a base with an amine of the formula III to the nitrocinnamamide IVa subsequently reduced to the amino compound V. and V is condensed with 3,4,5,6-tetrahydrophthalic anhydride. 3. A process for the preparation of the compounds I according to claim 1, wherein Y is chlorine or bromine, characterized in that a nitrocinnamamide of the formula IVb in an inert organic solvent with chlorine or bromine to cinnamic acid amide of formula IVc halogenated, then reduced and condensed with 3,4,5,6-tetrahydrophthalic anhydride. 4. A process for the preparation of the compound I according to claim 1, characterized in that a 5- (N-3,4,5,6-tetrahydrophthalimido) - cinnamic acid chloride of the formula VI in a conventional manner in an inert organic solvent with an amine of formula III to 5- (N-3,4,5,6-tetrahydrophthalimido) - cinnamamide I. 5. Use of the 5- (N-3,4,5,6-tetrahydrophthalimido) cinnamic acid amides of Formula I according to claim 1 as herbicides.   6. Herbicidal agents containing a 5- (N-3,4,5,6-tetrahydrophthalimido) - cinnamic acid amide of the formula I according to claim 1 and inert additives. 7. A herbicidal composition according to claim 6, containing a 5- (N-3,4,5,6- Tetrahydrophthalimido) cinnamamide of the formula I and other effective Ingredients. 8. A method for controlling undesired plant growth, thereby characterized in that the unwanted plants and / or their Habitat with a herbicidally effective amount of a 5- (N-3,4,5,6- Tetrahydrophthalimido) cinnamic acid I treated according to claim 1.