GB1566842A

GB1566842A - Chloromethane-sulphonic acid anilides and their use as herbicides

Info

Publication number: GB1566842A
Application number: GB2818/78A
Authority: GB
Original assignee: Bayer AG
Current assignee: Bayer AG
Priority date: 1977-01-28
Filing date: 1978-01-24
Publication date: 1980-05-08
Also published as: IL53887A; TR19388A; DK41178A; HU178434B; AU3267578A; ATA56478A; CA1093093A; DE2703477A1; IL53887A0; AT357361B; EG12964A; ZA78509B; IT7819681A0; AU516367B2; JPS5395940A; BR7800504A; BE863388A; SU654143A3; NL7800899A; FR2378754A1

Description

(54) NOVEL CHLOROMETHANESUI.PHONIC ACID ANILIDES AND THEIR USE AS HERBICIDES (71) We, BAYER AKTIENGESELLSCHAFT, a body corporate, organised under the laws of Germany, of Leverkusen, Federal Republic of Germany, do hereby declare the invention, for which we pray that a patent may be granted to use, and the method by which it is to be performed to be particularly described in and by the following statement: The present invention relates to certain new chloro-methanesulphonic acid anilides, to a process for their preparation and to their use as herbicides.

It has already been disclosed that methane-sulphonic acid 2 trifluoromethyl - 4- methylthio - anilide, methanesulphonic acid 2trifluoromethyl - 4 - methylsulphinyl - anilide and methane-sulphonic acid 2 trifluoromethyl - 4 - methylsulphonyl - anilide are suitable for combating weeds (see German Offenlegungsschrift (German Published Specification) 2,551,027).

However, the activity and the selectivity of these substances is not always completely satisfactory, especially in the case of low application amounts.

The present invention now provides, as new compounds, the chloromethanesulphonic acid 2 - trifluoromethyl - anilides of the general formula

in which n represents 0, 1 or 2.

The present compounds have been found to possess strong herbicidal properties.

The present invention also provides a process for the preparation of a chloromethanesulphonic acid 2 - trifluoro - methyl - anilide of the formula (I) in which (a) 2 - trifluoro - methyl - 4 - methylthio - aniline, of the formula

is reacted with chloromethanesulphonyl chloride, of the formula Cl-CH2-S02-Cl (III), in the presence of an acid acceptor and, if appropriate, in the presence of a diluent, and, if required, the chloro-methanesulphonic acid 2 - trifluoromethyl - 4 4. methylthioanilide thereby formed is subsequently oxidised, if appropriate in the presence of a diluent, or (b), when the compound of the formula (I) is such that n is to represent 1 or 2, 2 - trifluoromethyl - 4 - methylthioaniline, of the formula

is oxidised, if appropriate in the presence of a diluent, and the compound formed thereby, of the general formula

in which x represents 1 or 2, is reacted with chloromethanesulphonyl chloride, of the formula Cl-CH2-SO2-Cl (III), in the presence of an acid acceptor and, if appropriate, in the presence of a diluent.

Surprisingly, the chloromethanesulphonic acid 2- tri - fluoromethyl anilides according to the invention exhibit a higher herbicidal activity and abetter selectively than methanesulphonic acid 2 - trifluoromethyl - 4 - methylthio - anilide, methanesulphonic acid 2 - trifluoromethyl - 4 - methylsulphinyl - anilide and methanesulphonic acid 2 - trifluoromethyl - 4 - methylsulphonyl - anilide, which are compounds which are known from the state of the art and are chemically the most closely related active compounds having the same type of action. The substances according to the invention thus represent a valuable enrichment of the art.

If 2 - trifluoromethyl - 4 - methyl - thio - aniline and chloromethansulphonyl chloride are used as the starting materials and hydrogen peroxide is used as the oxidising agent, the course of reaction according to process variants (a) and (b) can be represented by the following equations: Variant (a)

The compounds of the formulae (II) and (III) required as starting materials are known (see German Offenlegungsshrift (German Published Specification) 2,551,027).

All the customary acid-binding agents can be used as acid acceptors in the reaction of 2- trifluoromethyl - 4- methyl - thio - aniline with chloromethanesulphonyl chloride according to process variant (a), especially alkali metal hydroxides, such as sodium hydroxide and potassium hydroxide; alkali metal carbonates, such as sodium carbonate and potassium carbonate; alkali metal alcoholates, such as sodium methylate and sodium ethylate; and aliphatic, aromatic or heterocyclic amines, such as, for example, triethylamine, dimethylamine, dimethylaniline, dimethylbenzylamine and pyridine.

All inert organic solvents can be used as the diluent in the reaction of 2 trifluoromethyl - 4 - methylthioaniline with chloromethanesulphonyl chloride according to process variant (a), especially aliphatic or aromatic hydrocarbons, such as petroleum ether, benzine, benzene, toluene and xylene; chlorinated aliphatic or aromatic hydrocarbons, such as methylene chloride, chloroform, carbon tetrachloride and chlorobenzene; ethers, such as diethyl ether, dibutyl ether, tetrahydrofuran and dioxan; and ketones, such as acetone. Moreover, water can also be employed as the diluent.

The reaction temperatures in the reaction of 2 - tri - fluoromethyl - 4 methylthio - aniline with chloromethanesulphonyl chloride can be varied within a relatively wide range. In general, the reaction is carried out at temperatures of from OOC to 800C, preferably from 100C to 500C.

In carrying out the reaction of 2 - trifluoromethyl - 4 - methylthio - aniline with chloromethanesulphonyl chloride according to process variant (a), 1 to 3 moles of chloro-methanesulphonyl chloride are generally employed per mole of 2 trifluoromethyl - 4- methylthio- aniline. When chloro-methanesulphonyl chloride is used in more than the equimolar amount, in addition to chloromethanesulphonic acid 2 - tri - fluoromethyl - 4 - methylthio - anilide, N,N - (bis - chloromethyl - sulphonyl) - 2 - trifluoromethyl 4 - methylthio aniline is also formed. However, the latter compound can be converted into the desired product by treatment with strong bases, such as, for example, potassium hydroxide. The reaction product is isolated by customary methods. In general, the procedure is to add a dilute strong acid to the reaction mixture. In some cases the reaction product thereby separates out in the crystalline form. If there is a large amount of N,N - (bis - chloromethylsulphonyl)- 2- trifluoromethyl - 4methylthio - aniline in the reaction mixture, after adding dilute acid the mixture is extracted with an organic solvent which is immiscible with water, the solvent is removed and the residue is treated with a strong base and subsequently acidified.

All the customary oxidising agents which release oxygen can be used in the oxidation of chloromethanesulphonic acid 2 - trifluoromethyl - 4 - methylthio anilide according to process variant (a), especially hydrogen peroxide, peracetic acid and m-chlorobenzoic acid.

In carrying out this oxidation, any of the organic solvents which can customarily be used for oxidations of this type can be employed as the diluent, especially glacial acetic acid and methylene chloride.

The reaction temperatures in the oxidation of chloro-methanesulphonic acid 2 - trifluoromethyl - 4 - methylthio - anilide according to process variant (a) can be varied within a relatively wide range. In general, the reaction is carried out at temneratures of from 0 C to 1200 C, preferably of from 50"C to 1000C.

In carrying out tne oxidation according to process vanant (a), an equlmovtr amount or an excess of oxidising agent with respect to the chloromethanesulphonic acid 2- trifluoromethyl - 4- methylthio - anilide are generally employed, depending on whether the sulphinyl or sulphonyl compound of the formula (I) is to be synthesised. Working up is carried out in accordance with customary methods.

In general, the procedure is to add water to the mixture after the reaction has ended. The reaction product thereby frequently separates out immediately in the crystalline form. If this is not the case, the reaction mixture is extracted with an organic solvent which is immiscible with water, the phases are separated and the solvent is removed.

Any of the customary oxidising agents which release oxygen can also be used in carrying out the oxidation of 2 - trifluoromethyl - 4 - methylthio - aniline according to process variant (b), especially those oxidising agents which have already been mentioned as preferred in connection with process variant (a).

In this oxidation also, any of the solvents which can customarily be used for reactions of this type can be employed as the diluent, especially glacial acetic acid and methylene chloride.

The reaction temperatures in carrying out the oxidation according to process variant (b) can be varied within a fairly wide range. In general, the reaction is carried out at temperatures of from 0 C to 120"C, preferably of from 50"C to 100"C.

In carrying out the oxidation according to process (b), the procedure is the same as in the corresponding reaction step of process variant (a).

All the customary acid acceptors can be used in the reaction of a compound of the formula (IV) with chloro-methanesulphonyl chloride according to process variant (b), especially those which have already been mentioned as preferred in connection with the corresponding reaction step of process variant (a).

All inert organic solvents can also be used as the diluent in this stage of process variant (b), especially those solvents which have already been mentioned as preferred in connection with the corresponding reaction step of process variant (a).

Furthermore, water can also be used as the diluent.

The temperatures in the reaction of a compound of the formula (IV) with chloromethanesulphonyl chloride can also be varied within a relatively wide range.

In general, the reaction is carried out at temperatures of from 0 C to 80"C, preferably of from 100C to 50"C.

In carrying out the reaction of a compound of the formula (IV) with chloromethanesulphonyl chloride, I to 3 moles of chloromethanesulphonyl chloride are generally employed per mole of an aniline of the formula (IV). The reaction products are isolated in accordance with the methods which have already been described in connection with the corresponding reaction of process variant (a).

The active compounds according to the invention influence plant growth and can therefore be used as defoliants, desiccants, agents for destroying broad-leaved plants, germination inhibitors and, especially, as weedkillers. By "weeds" in the broadest sense there are meant plants growing in places where they are not desired.

Whether the compounds according to the invention act as total herbicides or selective herbicides depends essentially on the amount used.

The active compounds according to the present invention may be used, for example, to combat the following plants: dicotyledon weeds such as mustard (Sinapis), cress (Lepidium), bed straw (Galium), chickweed (Stellaria), camomile (Matricaria), mayweed (Anth em is), gallant soldier (Galinsoga), goosefoot (Chenopodium), annual nettle (Urtica), groundsel (Senecio), pigweed (Amaranthus), purslane (Portulaca), cocklebur (Xanthium), bindweed (Convolvulus), morning glory (Ipomoea), knotweed (Polygonum), sesbania (Sesbania), ragweed (Ambrosia), spear thistle (Cirsiuntl, common thistle (Carduus), sow thistle (Sonchus), field cress (Rorippa), toothcup (Rotala), false pimpernel (Linderna), deadnettle (Lamium), speedwell (Veronica), mallow (Abutilon), emex (Emex), thornapple (Datura), violet (Viola), hemp-nettle (Galeopsis), poppy (Papaver), and knapweed (Centaurea), and nightshade (Solanum); and monocotyledon weeds such as barnyard grass (Echinochloa), foxtail (Setaria), wild millet (Panicum), crabgrass (Digitaria), timothy (Phleum), bluegrass (Poa), fescue (Festuca), goosegrass (Eleusine), signalgrass (Brachiaria), ryegrass (Lolium), cheat (Bromus), oats (Avena), flatsedge (Cvperus), sorghum (Sorghum), quackgrass (Agropyron), Bermuda grass (Cynodon), Monocharia, fimbristylis (Fimbristylis), arrowhead (Sagittaria), spikerush (Eleocharis), bulrush (Scirpus), paspalum (Paspalum), Ischaemum, gooseweed (Sphenoclea, crowfoot grass (Dactyloctenium), redtop (Agrostis), meadow foxtail (Alopecurus), and silky bentgrass (Apera), The active compounds according to the present invention may be used, for example, as selective herbicides in the following cultures: dicotyledon cultures such as cotton (Gossypium), soya bean (Glycine), beet (Beta), carrot (Daucus), bean (Phaseolus), pea (Pisum), potato (Solanum), flax (Linum), sweet potato (Ipomoea), broad bean (Vicia), tobacco (Nicotiana), tomato (Lycopersicon), groundnut (A rachis), cabbage (Brassica), lettuce (Lactuca), cucumber (Cucumis), and marrow (Cucurbita); and monocotyledon cultures such as rice (Oryza), maize (Zea), wheat (Triticum), barley (Hordeum), oats (Avena), rye (Secale), sorghum (Sorghum), millet (Panicum), sugar cane (Saccharum), pineapple (Ananas), asparagus (Asparagus) and onion (A ilium).

However, the use of the active compounds according to the invention is in no way restricted to these plants or even to the indicated genera but also embraces other plants, in the same way.

Depending on the concentration, the compounds can be used for the total combating of weeds, for example on industrial terrain and railway tracks and on paths and squares with and without trees. Equally, the compounds can be employed for combating weeds in perennial cultures, for example forestry plantings, decorative tree plantings, orchards, vineyards, citrus groves, nut orchards, banana plantations, coffee plantations, tea plantations, rubber plantations. oil nalm plantations, cacao plantations. soft fruit plantings and hopfields, and for the selective combating of weeds in annual cultures.

The chloromethanesulphonic acid 2 - trifluoromethyl - anilides according to the invention are especially suitable for the selective combating of weeds--above all for combating grass-like weeds in standing crops of cotton.

The active compounds can be coverted into the customary formulations, such as solutions, emulsions, suspensio,powders, pastes and granules.

These formulations may be produced in known manner, for example by mixing the active compounds with extenders, that is to say liquid or liquified gaseous or solid diluents or carriers, optionally with the use of surface-active agents, that is to say emulsifying agents and/or dispersing agents and/or foam-forming agents. In the case of the use of water as an extender, organic solvents can, for example, also be As liquid solvents diluents or carriers, especially solvents, there are suitable in the main, aromatic hydrocarbons, such as xylene, toluene or alkyl naphthalenes, chlorinated aromatic or chlorinated aliphatic hydrocarbons, such as chlorobenzenes, chloroethylenes or methylene chloride, aliphatic or alicyclic hydrocarbons, such as cyclohexane or paraffins, for example mineral oil fractions, 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, or strongly polar solvents, such as dimethylformamide and dimethylsulphoxide, as well as water.

By liquefied gaseous diluents or carriers are meant liquids which would be gaseous at normal temperature and under normal pressure, for example aerosol propellants, such as halogenated hydrocarbons as well as butane, propane, nitrogen and carbon dioxide.

As solid carriers there may be used ground natural minerals, such as kaolins, clays, talc, chalk, quartz, attapulgite, montmorillonite or diatomaceous earth, and ground synthetic minerals, such as highly-dispersed silicic acid, alumina and silicates. As solid carriers for granules there may be used crushed and fractionated natural rocks such as calcite, marble, pumice, sepiolite and dolomite, as well as synthetic granules of inorganic and organic meals, and granules of organic material such as sawdust, coconut shells, maize cobs and tobacco stalks.

As emulsifying and/or foam-forming agents there may be used non-ionic and anionic emulsifiers, such as polyoxyethylene-fatty acid esters, polyoxyethylenefatty alcohol ethers, for example alkylaryl polyglycol ethers, alkyl sulphonates, alkyl sulphates, aryl sulphonates as well as albumin hydrolysis products. Dispersing agents include, for example, lignin sulphite waste liquors and methylcellulose.

The active compounds according to the invention, as such or in their formulations, can be combined with other herbicidal active compounds to boost and supplement their spectrum of action, depending on the intended use; for this purpose, finished formulations or tank mixing may be employed.

Particularly preferred possible mixtures of the active compounds according to the invention are those with 3 - (3,4 - dichlorophenyl) - 1,1 - dimethyl - urea, 3 (3 - trifluoromethyl - phenyl) - 1,1 - dimethylurea, 3 - [3 - (1,1,2,2 - tetrafluoroethoxy) - phenyl] - 1,1 - dimethylurea, 2 - methylthio - 4,6 - bis - ethylamino 1,3,5 - triazine, 3 - (3,4 - dichlorophenyl) - 1 - methoxy - 1 - methyl - urea, 2 (3,4 - dichlorophenyl) - 4 - methyl - 1,2,4 - oxadiazoline - 3,5 - dione, 2 ethylthio - 4, 6 - (isopropylamino) - 1,3,5 - triazine and 3 - (3 - chloro - 4 trifluoromethoxyphenyl) - 1,1 - dimethylurea.

The active compounds according to the invention can be present in the formulations as mixtures with other active compounds, such as fungicides, insecticides and acaricides.

The formulations in general contain from 0.1 to 95 per cent by weight of active compound, preferably from 0.5 to 90 per cent by weight.

The active compounds can be used as such, as their formulations or as the use forms prepared therefrom, such as ready-to-use solutions, emulsions, suspensions, powders, pastes and granules. They may be used in the customary manner, for example by spraying, atomising, dusting, scattering and watering.

Preferably, they are used in accordance with the pre-emergence process.

The amount of active compound used can vary within a fairly wide range. It depends essentially on the nature of the desired effect. In general, the amounts used are from 0.1 to 20 kg of active compound per hectare, preferably from 0.2 to 15 kg/ha.

The present invention also provides a herbicidal composition containing as active ingredient a compound of the present invention in admixture with a solid or liquefied gaseous diluent or carrier or in admixture with a liquid diluent or carrier containing a surface-active agent.

The present invention also provides a method of combating weeds which comprises applying to the weeds, or to a habitat thereof, a compound of the present invention alone or in the form of a composition containing as active ingredient a compound of the present invention in admixture with a diluent or carrier.

The present invention further provides crops protected from damage by weeds by being grown in areas in which immediately prior to and/or during the time of the growing a compound of the present invention was applied alone or in admixture with a diluent or carrier.

It will be seen that the usual methods of providing a harvested crop may be improved by the present invention.

The herbicidal activity of the compounds of this invention is illustrated by the following biotest Examples.

In these Examples, the compounds according to the present invention are each identified by the number (given in brackets) of the corresponding preparative Example, which will be found later in this specification.

The known comparison compounds are identified as follows:

(known) (known) (known) 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 was mixed with the stated amount of solvent, the stated amount of emulsifier was added and the concentrate was diluted with water to the desired concentration.

Seeds of the test plants were sown in normal soil and, after 24 hours, watered with the preparation of the active compound. It was expedient to keep constant the amount of water per unit area. The concentration of the active compound in the preparation was of no importance, only the amount of active compound applied per unit area being decisive. After three weeks, the degree of damage to the plants was determined in % damage in comparison to the development of the untreated control. The figures denoted: OO/,=no action (like untreated control) 1000/,=total destruction The active compounds, the amounts applied and the results can be seen from the table which follows: TABLE A Pre-emergence test Amount of active com Active pound used Avena compound kg/ha Setaria Sinapis Galinsoga Stellaria Lolium Echinochloa fatua Cotton (1) 5 100 0 100 100 100 100 100 0 2.5 100 0 .80 100 100 100 100 0 (2) 5 100 80 80 100 100 100 100 0 2.5 100 60 80 100 100 100 100 0 (3) 5 100 40 60 100 100 100 100 0 2.5 100 20 40 100 100 100 100 0 (A) 5 100 40 20 60 100 100 80 40 2.5 100 0 0 60 80 100 60 20 (B) 5 80 0 40 40 60 80 80 20 2.5 80 0 0 40 60 60 60 0 (C) 5 80 40 60 80 80 80 80 0 2.5 80 0 40 80 80 80 60 0 Preparative Examples Example 1

31.6 g (0.153 mol) of 2 - trifluoromethyl - 4 - methylthio - aniline were dissolved in 100 ml of pyridine and 56.6 g (0.38 mol) of chloromethanesulphonyl chloride were added dropwise at OOC to 100C. The mixture was subsequently stirred for one hour at room temperature and the reaction solution was then introduced into dilute hydrochloric acid and extracted with methylene chloride.

After drying the organic phase solvent was stripped off. 50 g of a dark oil remained which essentially consisted of N,N - (bis - chloro - methylsulphonyl) - 2 trifluoromethyl - 4 - methylthio - aniline.

42 g of the oil were dissolved in 200 ml of methanol. 17 g (0.3 mol) of potassium hydroxide were added to this solution and the mixture was then stirred for some hours at room temperature. After some time, a crystalline product began to separate out. This was dissolved in water and acidified with hydrochloric acid. 28 g (90 /n of theory) of chloromethanesulphonic acid 2- trifluoromethyl - 4methylthio - anilide were hereby obtained in the form of a solid substance of melting point 98--99"C.

Example 2

10 g (0.031 mol) of chloromethanesulphonic acid 2 - trifluoromethyl - 4 methylthioanilide were dissolved in 50 ml of glacial acetic acid and 3.4 g (0.03 mol) of 30% strength hydrogen peroxide were added at 150C to 20"C. The mixture was stirred for a further 6 hours at 1 50C to 20"C, 100 ml of water were then added and the reaction mixture was extracted with methylene chloride. After drying the organic phase the solvent was stripped off. The slowly crystallising product which thereby remained was recrystallised from an ethanol/petroleum ether mixture. In this manner, 5 g (50% of theory) of chloromethanesulphonic acid 2trifluoromethyl - 4 - methylsulphinyl - anilide were obtained in the form of a solid substance of melting point 110--1130C.

Example 3

13 g (0.041 mol) of chloromethanesulphonic acid 2 - trifluoromethyl - 4 methylthio - anilide were dissolved in 50 ml of glacial acetic acid and 18 ml (0.16 mol) of 30% strength hydrogen peroxide were added at 60"C. The temperature of the reaction mixture thereupon rose to the boiling point. The mixture was heated under reflex for a further 2 hours and 50 ml of water were then added. On cooling, the reaction product separated out in the crystalline form. In this manner, 13 g (91% of theory) of chloromethanesulphonic acid 2- trifluoromethyl - 4methylsulphonyl - anilide were obtained in the form of a solid substance of melting point 190191 C.

Claims

WHAT WE CLAIM IS:

1. Chloromethanesulphonic acid 2 - trifluoromethyl - anilides of the general formula

in which n represents 0, 1 or 2.

2. A process for the preparation of a chloromethanesulphonic acid 2 trifluoromethyl - anilide according to claim 1 in which (a) 2 - trifluoromethyl - 4 - methylthio - aniline, of the formula

is reacted with chloromethanesulphonyl chloride, of the formula ClCH2-SO2-Cl (III), in the presence of an acid acceptor and, if appropriate, in the presence of a diluent and, if required, the chloromethane-sulphonic acid 2 - trifluoromethyl - 4 methylthioanilide thereby formed is subsequently oxidised, if appropriate in the presence of a diluent, or (b) when the compound of the formula (I) is such that n is to represent 1 or 2, 2 trifluoromethyl - 4 - methylthio - aniline, of the formula

is oxidised, if appropriate in the presence of a diluent, and the compound formed thereby of the formula

in which x represents 1 or 2, is reacted with chloromethanesulphonyl chloride, of the formula ClCH2-SO2-Cl (III), in presence of an acid acceptor and, if appropriate, in the presence of a diluent.

3. A process according to claim 2, in which the reaction with chloromethanesulphonyl chloride is effected in an inert organic solvent.

4. A process according to claim 2 or 3, in which the reaction with chloromethanesulphonyl chloride is effected in the presence, as an acid acceptor, of an alkali metal hydroxide, an alkali metal carbonate, an alkali metal alcoholate or an aliphatic, aromatic or heterocyclic amine.

5. A process according to claim 2, 3 or 4, in which the reaction with chloromethanesulphonyl chloride is effected at from OOC to 800 C.

6. A process according to claim 5, in which the said reaction is effected at from 10 C to 50 C.

7. A process according to any of claims 2 to 6, in which 1--3 moles of chloromethanesulphonyl chloride are employed per mole of the compound (II) or (IV).

8. A process according to any of claims 2 to 7 in which the oxidation is effected with hydrogen peroxide, peracetic acid or m-chlorobenzoic acid.

9. A process according to any of claims 2 to 8 in which the oxidation is effected in glacial acetic acid.

10. A process according to any of claims 2 to 9 in which the oxidation is effected at from 0 C to 1200C.

11. A process according to claim 10 in which the oxidation is effected at from 50"C to 1000C.

12. A process according to claim 2(a) or any of claims 3 to 11 as appendant to claim 2(a) in which more than I mole of chloromethanesulphonyl chloride is employed per mole of 2 - trifluoromethyl - 4 - methythio - aniline and the N,N (bis - chloromethylsulphonyl) - 2 - trifluoromethyl - 4 - methyl - thio - aniline so formed is converted into chloromethanesulphonic acid 2 - trifluoromethyl - 4 methylthio - anilide by reaction with a strong base.

13. A process for the preparation of a compound according to claim 1, substantially as described in any one of Examples I to 3.

14. Compounds according to claim 1 whenever prepared by a process according to any of claims 2 to 13.

15. A herbicidal composition containing as active ingredient a compound according to claim 1 or 14 in admixture with a solid or liquefied gaseous diluent or carrier or in admixture with a liquid diluent or carrier containing a surface-active agent.

16. A composition according to claim 15 containing from 0.1 to 95% of the active compound, by weight.

17. A method of combating weeds which comprises applying to the weeds, or to a habitat thereof, a compound according to claim 1 or 14 alone or in the form of a composition containing as active ingredient a compound according to claim 1 or 14, in admixture with a diluent or carrier.

18. A method according to claim 17 in which the active compound is applied to an area of agriculture in an amount of 0.1 to 20 kg per hectare.

19. A method according to claim 18 in which the active compound is applied to an area of agriculture in an amount of 0.2 to 15 kg per hectare.

20. A method according to claim 17, 18 or 19, in which the active compound is applied against weeds in standing crops of cotton.

21. Crops protected from damage by weeds by being grown in areas in which immediately prior to and/or during the time of the growing a compound according to claim 1 or 14 was applied alone or in admixture with a diluent or carrier.