WO1997008160A1

WO1997008160A1 - N-(1-isopropyl-2-methyl-1-propenyl)heteroaryloxyacetamides and the use thereof as herbicides

Info

Publication number: WO1997008160A1
Application number: PCT/EP1996/003521
Authority: WO
Inventors: Hans-Jochem Riebel; Yukinoshi Watanabe; Markus Dollinger; Hans-Joachim Santel
Original assignee: Bayer Aktiengesellschaft
Priority date: 1995-08-22
Filing date: 1996-08-09
Publication date: 1997-03-06
Also published as: DE19530767A1; AU6871696A

Abstract

The invention relates to novel N-(1-Isopropyl-2-methyl-1-propenyl)heteroaryloxyacetamides of formula (I) in which Het is optionally benzannellated and optionally substituted heteroaryl; and R is optionally substituted alkyl. It also relates to a method and novel intermediates for the preparation thereof, and the use thereof as herbicides.

Description

N- (l-IS0PR0PYL-2-METHYL-l-PR0PENYL) -HETER0ARYL0XYACETAMIDE AND THEIR USE AS HERBICIDES

The invention relates to N- (l-isopropyl-2-methyl-l-propenyl) heteroaryloxyacetamide, a process for their preparation and their use as herbicides.

It is known that certain N-alkyl- and N-alkenyl-heteroaryloxyacetamides have herbicidal properties (cf. EP 5501 and EP 18497). However, the action of these known compounds is not always entirely satisfactory.

The new N- (l-isopropyl-2-methyl-l-propenyl) heteroaryloxyacetamides of the general formula (I) have now been found

in which

Het stands for optionally benzannellated and optionally substituted hetero aryl and

R represents optionally substituted alkyl.

It was further found that the new N- (l-isopropyl-2-methyl-l-propenyl) heteroaryloxyacetamides of the formula (I) can be obtained if substituted heteroarenes of the general formula (II)

Het-X (II)

in which

Het has the meaning given above and X represents halogen, alkylthio, alkylsulfinyl or alkylsulfonyl,

with N- (l-isopropyl-2-methyl-l-propenyl) hydroxyacetamides of the general formula (m)

in which

R has the meaning given above,

if appropriate in the presence of a diluent and if appropriate in the presence of a reaction auxiliary.

Finally, it was found that the new N- (l-isopropyl-2-methyl-l-propenyl) heteroaryloxyacetamides of the general formula (I) have interesting herbicidal properties.

The invention preferably relates to compounds of the formula (I) in which

Het for optionally benzanellated and optionally substituted heteroaryl from the series oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, benzoxazolyl, benzthiazolyl, 1,2,4-oxadiazolyl, 1,3,4-oxadiazolyl, 1,2,4-thiadiazolyl, 1,3 , 4-thiadiazolyl, 1,2,5-thiadiazolyl, 1,2,4-triazolyl and tetrazolyl, the possible substituents preferably being selected from the series halogen, cyano, (each optionally substituted by fluorine and / or chlorine) ) Ci-Cg-alkyl, C ₂ -C 6 alkenyl, C ₂ -C ₆ alkynyl, Ci-Cg-alkoxy, CJ-C ₆ alkylthio, C j -Cg- alkylsulfinyl, Cι-C6-alkylsulfonyl, Cι- C ₆ alkyl sulfo nyl-methyl, C3-C6-cycloalkyl, phenyl, phenoxymethyl, benzylsulfonyl, pyridyl, furyl or thienyl, and

R represents straight-chain or branched alkyl with 1 to 6 carbon atoms which is optionally substituted by halogen or C _] -C4-alkoxy.

The invention relates in particular to compounds of the formula (I) in which

Het for optionally benzanellated and optionally substituted heteroaryl from the series 1,3-oxazol-2-yl, 1,3-thiazol-2-yl, benzoxazol-2-yl, benzothiazol-2-yl, 1,2,4 -Thiadiazol-5-yl, l, 3,4-thiadiazol-2-yl, l, 2,5-thiadiazol-3-yl, l, 2,4-triazol-3- (or 5-) yl and tetrazole -5-yl, where the possible substituents are preferably selected from the series fluorine, chlorine, bromine, cyano, (each optionally substituted by fluorine and / or chlorine) methyl, ethyl, n- or i-propyl, n- , i-, s- or t-butyl, methoxy, ethoxy, n- or i-propoxy, methylthio, ethylthio, n- or i-propylthio, methylsulfinyl, ethylsulfinyl, n- or i-propylsulfinyl, methylsulfonyl, ethylsulfonyl, n- or i-propylsulfonyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, phenyl, pyridyl, furyl or thienyl, and

R in each case represents methyl, ethyl, n- or i-propyl, n-, i- or s-butyl optionally substituted by fluorine, chlorine, methoxy or ethoxy.

The general definitions given above or those specified in preferred ranges apply both to the end products of the formula (I) and correspondingly to the starting materials or intermediates required in each case for the preparation. These radical definitions can be combined with one another as desired, that is to say also between the specified ranges of preferred compounds.

If, for example, 2,4,5-trichlorothiazole and N- (l-isopropyl -2-methyl-l-propenyl) -N-methyl-hydroxyacetamide are used as starting materials, the reaction sequence in the method according to the invention are outlined by the following formula:

⁰

Formula (II) provides a general definition of the substituted heteroarenes to be used as starting materials in the process according to the invention for the preparation of the compounds of the general formula (I). In the formula (II), Het preferably or in particular has the meaning which has already been mentioned above in connection with the description of the compounds of the formula (I) as preferred or as particularly preferred for Het; X preferably represents fluorine, chlorine, bromine, C1-C4-alkylthio, C} -C4-alkylsulfinyl or Cj-C-i-alkylsulfonyl, in particular chlorine or methylsulfonyl.

The starting materials of the formula (II) are known and / or can be prepared by processes known per se (cf. J. Org. Chem. 27 (1962), 2589-2592; EP-A 5501; EP-A 18497; EP-A 165537; EP-A 308740; EP-A 348735; EP-A 348737).

Formula (III) provides a general definition of the N- (l-isopropyl-2-methyl-l-propenyl) hydroxyacetamides to be used as starting materials in the process according to the invention for the preparation of the compounds of the formula (I). In formula (III), R preferably or in particular has the meaning which has already been given above as preferred or as particularly preferred for R in the description of the compounds of formula (I).

The starting materials, the formula (III) are not yet known from the literature; as new substances, they are also the subject of the present application. The new N- (l-isopropyl-2-methyl-l-propenyl) -hydroxyacetamides of the formula (III) are obtained if N- (l-isopropyl-2-methyl-l-propenyl) -chloroacetamides of the formula (IV )

^

in which

R has the meaning given above,

with an alkali metal acetate, e.g. Sodium or potassium acetate, optionally in the presence of acid acceptors, e.g. Potassium carbonate and triethylamine, reacted at temperatures between 80 ° C and 150 ° C and then reacted with methanol at temperatures between 40 ° C and 80 ° C (cf. the preparation examples).

N- (l-isopropyl-2-methyl-l-propenyl) chloroacetamides of the formula (IV) are known and / or can be prepared by processes known per se (cf. DE 2526868, US Pat. No. 4258196).

The usual organic solvents are suitable as diluents for carrying out the process according to the invention. These include in particular aliphatic, alicyclic or aromatic, optionally halogenated hydrocarbons, such as, for example, pentane, hexane, heptane, petroleum ether, ligroin, gasoline, benzene, toluene, xylene, chlorobenzene, dichlorobenzene, cyclohexane, methylcyclohexane, dichloromethane, chloroform, tetrachloromethane ; Ethers such as diethyl ether, diisopropyl ether, t-butyl methyl ether, t-pentyl methyl ether, dioxane, tetrahydrofuran, ethylene glycol dimethyl or diethyl ether, diethylene glycol dimethyl ether or diethyl ether; Ketones such as acetone, butanone, methyl isopropyl ketone or methyl isobutyl ketone; Nitriles such as acetonitrile, propionitrile, butyronitrile or benzonitrile; Amides, such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methylformanilide, N- Methyl pyrrolidone or hexamethyl phosphoric acid triamide; Esters such as methyl acetate, ethyl ester, n- or i-propyl ester, n-, i- or s-butyl ester; Sulfoxides such as dimethyl sulfoxide; Alcohols, such as methanol, ethanol, n- or i-propanol, n-, i-, s- or t-butanol, ethylene glycol monomethyl ether or monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether; their mixtures with water or pure water.

The process according to the invention is preferably carried out in the presence of a suitable reaction auxiliary. All conventional inorganic or organic bases are suitable as such. These include, for example, alkali metal or

Alkaline earth metal hydrides, hydroxides, amides, alcoholates, acetates, carbonates or hydrogen carbonates, such as, for example, lithium, sodium, potassium or calcium hydride, lithium, sodium or potassium amide, sodium or Potassium methylate, sodium or potassium ethylate, sodium or potassium propylate, aluminum isopropylate, sodium or potassium tert-butoxide, sodium or potassium hydroxide,

Ammonium hydroxide, sodium, potassium or calcium acetate, ammonium acetate, sodium, potassium or calcium carbonate, ammonium carbonate, sodium or potassium hydrogen carbonate, and basic organic nitrogen compounds, such as trimethylamine, triethylamine, tripropylamine, tributylamine, ethyl-diisopropylamine , N, N-dimethylcyclohexylamine, dicyclohexylamine, ethyl-dicyclohexylamine, N, N-dimethylaniline, N, N-dimethyl-benzylamine, pyridine, 2-methyl-, 3-methyl- and 4-methyl-pyridine, 2,4 -Dimethyl-, 2,6-dimethyl-, 3,4-dimethyl- and 3,5-dimethyl-pyridine, 5-ethyl-2-methyl-pyridine, N-methylpiperidine, N, N-dimethylaminopyridine, diazabicyclo-octane ( DABCO), diazabicyclonones (DBN) or diazabicycloundecene (DBU).

The reaction temperatures can be varied within a substantial range when carrying out the process according to the invention. In general, temperatures between -50 ° C and + 150 ° C, preferably at temperatures between -30 ° C and + 100 ° C, in particular at temperatures between -10 C and + 50 ° C. The process according to the invention is generally carried out under normal pressure. However, it is also possible to work under increased or reduced pressure - generally between 0.1 bar and 10 bar.

To carry out the method according to the invention, the respectively required ones are used

Starting materials are generally used in approximately equimolar amounts. However, it is also possible to use one of the two components used in each case in a larger excess. The reactions are generally carried out in a suitable diluent in the presence of a reaction auxiliary, and the reaction mixture is stirred for several hours at the temperature required in each case. Working up in the process according to the invention is carried out in each case by customary methods (cf. the preparation examples).

The active compounds according to the invention can be used as defoliants, desiccants, haulm killers and in particular as weed killers.

Weeds in the broadest sense are understood to mean all plants that grow up in places where they are undesirable. Whether the substances according to the invention act as total or selective herbicides depends essentially on the amount used.

The active compounds according to the invention can e.g. can be used in the following plants:

Dicotyledon weeds of the genera: Sinapis, Lepidium, Galium, Stellaria, Matricaria, Anthemis, Galinsoga, Chenopodium, Urtica, Senecio, Amaranthus, Portulaca, Xanthium, Convolvulus, Ipomoea, Polygonum, Sesbania, Ambrosia, Cirsium, Carduus

Sonchus, Solanum, Rorippa, Rotala, Lindernia, Lamium, Veronica, Abutilon, Emex, Datura, Viola, Galeopsis, Papaver, Centaurea, Trifolium, Ranunculus, Taraxacum.

Dicotyledon cultures of the genera: Gossypium, Glycine, Beta, Daucus, Phaseolus, Pisum, Solanum, Linum, Ipomoea, Vicia, Nicotiana, Lycopersicon, Arachis, Brassica,

Lactuca, cucumis, cucurbita. Monocotyledonous weeds of the genera: Echinochloa, Setaria, Panicum, Digitaria, Phleum, Poa, Festuca, Eleusine, Brachiaria, Lolium, Bromus, Avena, Cyperus, Sor¬ ghum, Agropyron, Cynodon, Monochoria, Fimbristylis, Sagittirpum, Eleocharis, Pas , Ischaemum, Sphenoclea, Dactyloctenium, Agrostis, Alopecurus, Apera.

Monocot cultures of the genera: Oryza, Zea, Triticum, Hordeum, Avena, Seeale, Sorghum, Panicum, Saccharum, Pineapple, Asparagus, Allium.

However, the use of the active compounds according to the invention is by no means restricted to these genera, but extends in the same way to other plants.

Depending on the concentration, the compounds are suitable for total weed control, e.g. on industrial and track systems and on paths and squares with and without tree cover. The compounds for weed control in permanent crops, e.g. Forest, ornamental wood, fruit, wine, citrus, nut, banana, coffee, tea, rubber, oil palm, cocoa, berry fruit and hop plants, on ornamental and sports turf and pasture land and can be used for selective weed control in annual crops.

The compounds of formula (I) according to the invention are particularly suitable for the selective control of monocotyledon and dicotyledon weeds in dicotyledon crops, especially in the pre-emergence process.

The active ingredients can be converted into the usual formulations, such as

Solutions, emulsions, wettable powders, suspensions, powders, dusts, pastes, soluble powders, granules, suspension emulsion concentrates, active ingredient-impregnated natural and synthetic substances as well as very fine encapsulations in polymeric substances.

These formulations are prepared in a known manner, e.g. B. by mixing the active ingredients with extenders, that is liquid solvents and / or solid Carriers, where appropriate using surface-active agents, that is to say emulsifiers and / or dispersants and / or foam-generating agents.

If water is used as an extender, e.g. organic solvents can also be used as auxiliary solvents. The following are essentially suitable as liquid solvents: aromatics, such as xylene, toluene, or alkylnaphthalenes, chlorinated aromatics and chlorinated aliphatic hydrocarbons, such as chlorobenzenes, chlorethylenes or methylene chloride, aliphatic hydrocarbons, such as cyclohexane or paraffins, e.g. Petroleum fractions, mineral and vegetable oils, alcohols such as butanol or glycol as well as their ethers and esters, ketones such as

Acetone, methyl ethyl ketone, methyl isobutyl ketone or cyclohexanone, strongly polar solvents such as dimethylformamide and dimethyl sulfoxide, and water.

Possible solid carriers are: e.g. Ammonium salts and natural rock flours, such as kaolins, clays, talc,

Chalk, quartz, attapulgite, montmorillonite or diatomaceous earth and synthetic rock powder, such as highly disperse silica, aluminum oxide and silicates, are suitable as solid carriers for granules: e.g. broken and fractionated natural rocks such as calcite, marble, pumice, sepiolite, dolomite and synthetic granules from inorganic and organic flours as well as granules from organic material such as sawdust, coconut shells, corn cobs and tobacco stems; as emulsifying and / or foaming agents are possible: e.g. nonionic and anionic emulsifiers such as polyoxyethylene fatty acid esters, polyoxyethylene fatty alcohol ethers, e.g. Alkylaryl polyglycol ethers, alkyl sulfonates, alkyl sulfates, aryl sulfonates and protein hydrolyzates; come in as dispersants

Question: e.g. Lignin liquor and methyl cellulose.

Adhesives such as carboxymethyl cellulose, natural and synthetic polymers in the form of powders, granules or latices, such as gum arabic, polyvinyl alcohol, polyvinyl acetate, and natural phospholipids such as cephalins and lecithins and synthetic phospholipids can be used in the formulations. Other additives can be mineral and vegetable oils. Dyes such as inorganic pigments, for example iron oxide, titanium oxide, ferrocyan blue and organic dyes such as alizarin, azo and metal phthalocyanine dyes and trace nutrients such as salts of iron, manganese, boron, copper, cobalt, molybdenum and zinc can be used.

The formulations generally contain between 0.1 and 95 percent by weight of active compound, preferably between 0.5 and 90%.

The active compounds according to the invention, as such or in their formulations, can also be used in a mixture with known herbicides for combating weeds, finished formulations or tank mixes being possible.

Known herbicides, for example anilides, such as e.g. Diflufenican and Propanil; Aryl carboxylic acids, e.g. Dichloropicolinic acid, dicamba and picloram; Aryloxyalkanoic acids, e.g. 2,4-D, 2,4-DB, 2,4-DP, fluroxypyr, MCPA, MCPP and triclopyr; Aryloxy-phenoxy-alkanoic acid esters, e.g. Diclofop-methyl, fenoxaprop-ethyl, fluazifop-butyl, haloxyfop-methyl and quizalofop-ethyl; Azinones, e.g. Chloridazon and norflurazon; Carbamates, e.g. Chloropropham, desmedipham, phenmedipham and propham; Chloroacetanilides, e.g.

Alachlor, acetochlor, butachlor, metazachlor, metolachlor, pretilachlor and propachlor; Dinitroanilines, e.g. Oryzalin, pendimethalin and trifluralin; Diphenyl ethers, e.g. Acifluorfen, Bifenox, Fluoroglycofen, Fomesafen, Halosafen, Lactofen and Oxyfluorfen; Ureas, e.g. Chlorotoluron, diuron, fluometuron, isoproturon, linuron and methabenzthiazuron; Hydroxylamines, e.g. Alloxydim, clethodim,

Cycloxydim, sethoxydim and tralkoxydim; Imidazolinones such as imazethapyr, imazamethabenz, imazapyr and imazaquin; Nitriles such as bromoxynil, dichlobenil and ioxynil; Oxyacetamides such as mefenacet; Sulfonylureas, such as, for example, amidosulfuron, bensulfuron-methyl, chlorimuron-ethyl, chlorosulfuron, cinosulfuron, metsulfuron-methyl, nicosulfuron, primisulfuron, pyrazosulfuron-ethyl, thifensulfuron-methyl, triasulfuron and tribenuron-methyl; Thiol carbamates such as butylates, cycloates, dialates, EPTC, esprocarb, molinates, prosulfocarb, thiobencarb and tri allate; Triazines, such as, for example, atrazine, cyanazine, simazin, simetryne, terbutryne and terbutylazine; Triazinones such as hexazinone, metamitron and metribuzin; Others, such as, for example, aminotriazole, Benfüresate, Bentazone, Cinmethylin, Clomazone, Clopyralid, Difenzoquat, Dithiopyr, Ethofümesate, Fluorochloridone, Glufosinate, Glyphosate, Isoxaben, Pyridate, Quinchlorac, Quinmerac, Sulphosate and Tridiphane.

A mixture with other known active compounds, such as fungicides, insecticides, acaricides, nematicides, bird repellants, plant nutrients and agents which improve soil structure, is also possible.

The active compounds can be used as such, in the form of their formulations or in the use forms prepared therefrom by further dilution, such as ready-to-use solutions, suspensions, emulsions, powders, pastes and granules. They are used in the usual way, e.g. by pouring, spraying, spraying, sprinkling.

The active compounds according to the invention can be applied both before and after emergence of the plants. They can also be worked into the soil before sowing.

The amount of active ingredient used can vary over a wide range. It essentially depends on the type of effect desired. In general, the application rates are between 10 g and 10 kg of active ingredient per hectare of soil, preferably between 50 g and 5 kg per ha.

The preparation and use of the active compounds according to the invention can be seen from the examples below. Manufacturing examples:

example 1

^

V ^

A solution of 0.5 g of sodium hydroxide in 1 ml of water is added dropwise with stirring to an ice-cooled mixture of 2.3 g (10 mmol) of N- (l-isopropyl-2-methyl-1-propenyl) -N - (2-methoxy-ethyl) -hydroxyacetamide, 2.8 g (10 mmol) 2-

Methylsulfonyl-5-trifluoromethyl-l, 3,4-thiadiazole and 30 ml of acetone are added and the reaction mixture is stirred for approximately 18 hours at a maximum of 25 ° C. after removing the ice bath. It is then concentrated in a water jet vacuum, the residue is taken up in methylene chloride, washed with water, dried with sodium sulfate and filtered. The solvent is carefully distilled off from the filtrate in a water jet vacuum.

3.7 g (74% of theory) of N- (l-isopropyl-2-methyl-l-propenyl) -N- (2-methoxy-ethyl) -2- (5-trifluoromethyl-l, 3.4) are obtained -thiadiazol-5-yl-oxy) -acetamide from Refrak-

_ ₂ o tion index ^Π D = 1.4780.

Analogously to Example 1 and in accordance with the general description of the production process according to the invention, the compounds of the formula (I) listed in Table 1 below can also be prepared, for example.

Table 1: Examples of the compounds of the formula (I)

E.g. no. Het R physical. Data

-CH ₂ CH ₂ OCH ₃ n ² _D ° _{= 1 4960}

N

N nH ₇ C ₃ - S0 ₂

Table 1 (continued)

E.g. no. Het R physical. Data

10 N - N -CH ₂ CH ₂ OCH ₃ n ²⁰ ⁿ D = 1.5242 // \\

CIFCH "

12 N - N - CH ₂ CH ₂ OCH ₃ , ² 0

'D = 1.5396

'/ \\

NC

13 -CH ₂ CH ₂ OCH ₃ m.p .: 102 ° C

14 _{1 5290}

Table 1 (continued)

E.g. no. Het R physical. Data

15 H ₃ CS0 ₂ , Y -NIN -CH ₂ CH ₂ OCH ₃ n ² _D ° _{= 1 5230}

17 -CH ₂ CH ₂ OCH ₃ m.p .: 132 ° C

18 -CH ₂ CH ₂ OCH ₃ m.p .: 88 ° C

19 H ₃ C _{1 5090}

20 -CH ₂ CH ₂ OCH ₃ ⁿ D ° = 1.5195

Table 1 (continued)

E.g. no. Het R physical. Data

23 -CH ₂ CH ₂ OCH _{3 n} » _{s lj5284}

25 -CH ₂ CH ₂ OCH ₃ m.p .: 100 ° C

^

N = N

Starting materials of the formula (IIP:

Example Oü-tt

A mixture of 49.5 g (0.20 mol) of N- (l-isopropyl-2-methyl-l-propenyl) -N- (2-methoxy-ethyl) -chloroacetamide, 6.0 g of potassium carbonate and 3 ml of triethylamine 57.4 g (0.70 mol) of sodium acetate are added at 120 ° C. and the reaction mixture is stirred at 120 ° C. for about 60 minutes. Then 100 ml of methanol are added at about 50 ° C. and the mixture is heated under reflux for about 4 hours. The mixture is then concentrated in a water jet vacuum, the residue is taken up in methylene chloride, washed with water, dried with sodium sulfate and filtered. The solvent is then carefully distilled off from the filtrate in a water jet vacuum.

39 g (85% of theory) of N- (l-isopropyl-2-methyl-l-propenyl) -N- (2-methoxy-ethyl) -hydroxyacetamide are obtained as an oily residue. Boiling point: 108 ° C-110 ° C at 1 mbar.

Examples of use:

Example A

Pre-emergence test

Solvent: 5 parts by weight of acetone

Emulsifier: 1 part by weight of alkylaryl polyglycol ether

To produce a suitable preparation of active compound, 1 part by weight of active compound is mixed with the stated amount of solvent, the specified amount is given

Amount of emulsifier and dilute the concentrate with water to the desired concentration.

Seeds of the test plants are sown in normal soil. After about 24 hours, the active ingredient preparation is poured onto the floor. The amount of water per unit area is expediently kept constant. The concentration of active substance in the preparation is irrelevant, the only decisive factor is the amount of active substance applied per unit area.

After three weeks, the degree of damage to the plants is rated in% damage compared to the development of the untreated control.

It means:

0% = no effect (like untreated control)

100% = total annihilation

In this test, for example, the compounds according to Preparation Examples 1 and 2 show a strong action against weeds. With an active ingredient application rate of 2kg / ha, these active ingredients have an effect of 80% against abutilone, for example, against Alopecurus, Cyperus, Setaria and Sinapis each of 100%. Table A: Pre-emergence test / greenhouse

Active ingredient effort- Alo-Cype- Se- Abu- Sinapis amount pecurus rus taria tilon (g / ha)

0)

(2)

Claims

1. N- (l-isopropyl-2-methyl-l-propenyl) heteroaryloxyacetamide of the general formula (I),

in which

Het stands for optionally benzannellated and optionally substituted heteroaryl and

R represents optionally substituted alkyl.

2. Compounds of formula (I) according to claim 1, characterized in that therein

Het for optionally benzanellated and optionally substituted heteroaryl from the series oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, benzoxazolyl, benzthiazolyl, 1,2,4-oxadiazolyl, 1,3,4-oxadiazolyl, 1,2,4-thiadiazolyl, 1,3 , 4-thiadiazolyl, 1,2,5-thiadiazolyl, 1,2,4-

Triazolyl and tetrazolyl is available, the possible substituents preferably being selected from the series halogen, cyano, (in each case optionally substituted by fluorine and / or chlorine) C 1 -C 6 -alky !, C ₂ -C 6 alkenyl, C ₂ -C ₆ -alkynyl, -C-C ₆ -alkoxy, Cj-Cö-alkylthio, C \ - Cß- alkylsulfinyl, Cι-C ₆ - alkylsulfonyl, Cι-C6-alkylsulfonyl-methyl,

C ₃ -C 6 cycloalkyl, phenyl, phenoxymethyl, benzylsulfonyl, pyridyl, furyl or thienyl, and R represents straight-chain or branched alkyl having 1 to 6 carbon atoms which is optionally substituted by halogen or C1-C4-alkoxy.

3. Compounds of formula (I) according to claim 1, characterized in that therein

Het for optionally benzanellated and optionally substituted heteroaryl from the series l, 3-oxazol-2-yl, l, 3-thiazol-2-yl, benzoxazol-2-yl, benzothiazol-2-yl, 1,2,4 -Thiadiazol-S-yl, 1,3,4-thiazad-2-yl, l, 2,5-thiadiazol-3-yl, l, 2,4-triazol-3- (or 5-) yl and tetrazol-5-yl, the possible substituents preferably being selected from the series fluorine, chlorine, bromine, cyano, (in each case optionally substituted by fluorine and / or chlorine) methyl, ethyl, n- or i-propyl, n-, i-, s- or t-butyl, methoxy, ethoxy, n- or i-

Propoxy, methylthio, ethylthio, n- or i-propylthio, methylsulfinyl, ethylsulfinyl, n- or i-propylsulfinyl, methylsulfonyl, ethylsulfonyl, n- or i-propylsulfonyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, phenyl, pyridyl, furidyl or thienyl, and

R stands for methyl, ethyl, n- or i-propyl, n-, i- or s-butyl which is optionally substituted by fluorine, chlorine, methoxy or ethoxy.

4. A process for the preparation of compounds of formula (I) according to claim 1, characterized in that substituted heteroarenes of the general

Formula (II)

Het-X (II) in which

Het has the meaning given in claim 1 and X represents halogen, alkylthio, alkylsulfinyl or alkylsulfonyl,

with N- (l-isopropyl-2-methyl-l-propenyl) hydroxyacetamides of the general formula (ffl)

in which

R has the meaning given in claim 1,

5. Herbicidal agents, characterized in that they contain at least one compound of the formula (I) according to Claim 1.

6. Use of compounds of general formula (I) according to claim 1 for combating undesirable plant growth.

7. A method of combating weeds, characterized in that compounds of the general formula (I) according to Claim 1 are allowed to act on the weeds or their habitat.

8. A process for the preparation of herbicidal compositions, characterized in that compounds of the general formula (I) according to Claim 1 with

Extenders and / or surfactants mixed.

9. N- (l-isopropyl-2-methyl-l-propenyl) hydroxyacetamide of the general formula (III)

in which

R represents optionally substituted alkyl.