IL30584A - Herbicidal compositions containing carboxylic acid(1,2,4-thiadiazolyl-5)-amides and new carboxylic acid(1,2,4-thiadiazolyl-5)-amides - Google Patents

Description

Herb^cidal compositions containing carbox lic acid (lt2!'i4-thiadiazOlyI-5)--ainides and new carboxylic acid (1,2, -thiadiazolyl-5 )-amidee PARBENFABRIKEN BAYER AKTIENOBSELLSCHAPT C: 28813 The Invention consists in herbicidal compositions containing as an active ingredient a carboxylio acid (1,2,4-thiadlazol l-5)-amide, of the formula N C-R» in which R is alkyl with 1-4 carbon atoms, haloalkyl with 1-4 carbon atoms, alkoxy with 1-4 parbon atoms or phenoxy, and R* is alkyl with 1-4 carbon atoms or phenyl.

It is known that carboxylio acid amides, such as propionic acid 3t4-dichloroanilide (German Auslegeschrift 1039779)» carbamates, such as isopropyl-N-3-chlorophenylcarbamate (American Patent Specification 2734911); and thiazolylureas, such as N-(5-me-ttylthia2olyl-2)-Ef'-methylurea (Belgian Patent Specification 679138) can be used as herbicides.

It has now surprisingly been found that the carboxylio acid amides of formula 1 exhibit a stronger herbicidal potency and, in particular, a higher selective herbicidal activity, than the already known compounds.

Some of the compounds of formula 0.) namely those in which R is haloalkyl with 1-4 carbon atoms, alkoxy with 1-4 carbon atoms or phenoxy and R1 has the same meaning as above are new and form part of the present invention.

The invention also provides a process for the production of the new carboxylio acid amides aforesaid In which (a) a carboxylic acid halide of the formula R-CO-Hal (2) is reacted, in the presence of an acid binder, with a 5-amino-thiadiazole of the formula N C-R* II ii (3) HJJ-C H 2 in which formulae R is haloalkyl with 1-4 carbon atoms, alkoxy with 1-4 carbon atoms or phenoxy, R' has the same meaning as in formula (1) above, and Hal is halogen, or (b) an acid anhydride of the formula i which R has the meaning stated under (a) above io reacted with a 5-aminothiadiazole of formula (3).

If monochloroacetyl ohlorlde and 3-phenyl-5-amino-1,2,4-thiadiazole are used as starting materials, the reaction acoording to variant (a) can be- represented by the following reaction shceme: The carboxylic acid halides to be used according to the invention are, for example: monochloroacetyl 30584/2 - 4 -chloride, dichloroacetyi chloride, 3-chloropropionyl chloride, propionyl chloride and the methyl ester of chloroformic . acid.

In formula (l) above, R is preferably alkyl with 1-3. carbon atoms, haloalkyl with 1 or 2 carbon atoms' .which 'contains 1-4 atoms of chlorine, fluorine and/or bromine, alkoxy with 1 or 2 carbon atoms or phenoxy.

Some of tn©0© aminothiadiazoles are iknown.

Below are given further details for the two variants (a) and (b) .

The reaction may take place in the presence of a solvent (this term includes mere diluents).

As solvents, inert organic solvents are especially suitable. These include hydrocarbons, such as benzene, toluene; ethers, such as diethyl ether, tetrahydrofuran, dioxan; esters, such as methyl acetate or ethyl acetate; and nitriles, such as acetonitrile. In variant (b), an excess of the anhydride is preferably used as solvent.

As acid binders, «QT the usual acid-binding agents can be used. Alkali metal hydroxides, al kali metal carbonates and tertiary amines are preferred. Especially suitable are triethyl amine and pyridine.

The reaction temperatures can be varied within a fairly wide range. In general, the work is carried out at 20° to 120°C, preferably from 20° to 100°C.

When carrying out the process according to the invention, approximately 1 mole of acid chloride or 1-2 moles of acid anhydride are used to 1 mole of aminothiadiazole. The working up of the reaction mixture may take place in the usual manner.

The active compounds according to the invention influence plant growth and can therefore be used for defoliation or for desiccation of the green parts of plants. In this case they may serve as harvest auxiliaries to facilitate harvesting. They are, however, particularly suitable for the control of weeds. By weeds in the widest sense are meant all plants which grow in places where they are not desired. Whether the substances according to the invention act as total or selective herbicides depends essentially on the amount applied.

The substances according to the invention can be used for example in the case of the following plants: dicotyledons, such as mustard (Sinapis), cress (lepidium), cleaver (Galium), common chickweed (Stellaria), mayweed (Matricaria), small-flower Gralinsoga (GeJLinsoga) , fathen (Chenopodium) , stinging nettle (Urtica), groundsel (Senecio), cotton (Qossypium), beets (Beta), carrots (Daucus), beans (Phaseolus), potatoes (Solanum), coffee (Coffea); monocotyledons, such as timothy (Fhleum), bluegrass (Foa fescue (Festuca), goosegrass (El-eusine), foxtail (Setaria), ryegrass (Lolium), cheat (Bromus), barnyard grass (Echinochloa) , maize (Zea), rice (Oryza), oats (Avena), barley (Hcnxbum), wheat (Triticum), millet (Fanicum), sugar cane (Saccharum).

The active compounds according to the present invention can be converted into the usual formulations , such as solu the active compounds with extenders, that is, liquid or solid diluents or carriers, optionally with the use of surface-active agents, that is, emulsifying agents and/or dispersing agents. In the case of the use of water as an extender, organic solvents can, for example, also be used as auxiliary solvents.

As liquid diluents or carriers, there are preferably used aromatic hydrocarbons,, such as xylenes o benzene, chlorinated aromatic hydrocarbons, such as chlorobenzenes, paraffins, such as mineral oil fractions, alcohols, such as methanol or butanol, or strongly polar solvents, such as dimethyl formamide or dimethyl sulphoxide, as well as water.

As solid diluents or carriers, there are preferably used ground natural minerals, such as kaolins, clays, talc or cheJJc, or ground synthetic minerals, such as highly-dispersed silicic acid or silicates.

Preferred examples of emulsifying agents include non-ionic and anionic emulsifiers, such as polyoxyethylene-fatty acid esters, polyoxyethylehe-fatty alcohol ethers, for example alkylarylpolyglycol ethers, alkyl sulphonates and aryl sulphonates; and preferred examples of dispersing agents include lignin, sulphite waste liquors and methyl cellulose.

The active compounds according to the invention may be present in the formulations in admixture with other active compounds.

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

The active compounds may be used as such or in the form of their formulations or of the application forms prepared therefrom, such as ready-to-use solutions, emulsions, . spraying, atomising, dusting or scattering.

The active compounds according to the invention may be used according to both the pre-emergence method and the post-emergence method, that is before or after emergence of the plants.

The formulations may be diluted for actual application. Vhen the active compounds are used according to the post-emergence method, the concentration of active compound can be varied within fairly wide application ranges, in general from 0.1 to 5% by weight. When used according to the pre-emergence method the amount applied oan also be varied within fairly wide ranges, in general* from 1 to 50 kg per hectare.

The invention also provides a herbicidal composition containing as active ingredient a carboxylic acid amide according to formula (1) in admixture with a solid diluent or carrier or in admixture with a liquid diluent or carrier containing a surface-active agent.

The invention also provides a method of combating weeds which comprises applying to the weeds or to a weed habitat a carboxylic acid amide according to formula (l) alone or in the form of a composition containing as active ingredient a carboxylic acid amide according to formula(l) in admixture with a solid or liquid diluent or carrier.

The invention also provides a method of defoliating plants which comprises applying to the plants a carboxylic acid amide according to formula (1) alone or in admixture with a solid or liquid diluent or carrier whereby the leaves of the plants are caused to fall off or die.

The inventioB also provides crops protected from damage by weeds by being grown in areas in which immediately rior to and/or during the time of the growing a carboxylic The effectiveness of the . compounds according to the invention is demonstrated by the following Examples A and B.

The process according to the invention is illustrated by the following Examples 1 and 2.

Pre-emergence test Solvent: 5 parts by weight acetone Bmulsifier: 1 part by weight alk laryl 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 stated amount of emulsifer is added and the concentrate is then diluted with water to the desired concentration.

Seeds of the test plants are sown in normal soil and, after 24 hours, watered with the preparation of the active compound. It is expedient to keep constant the amount of water per unit area. The concentration of the active compound in the preparation is of no importance, only the amount of active compound applied per unit area being decisive. After three weeks, the degree of damage to the test plants is determined and characterised by the values 0-5» which have the following meaning: 0 no effect 1 slight damage or delay in growth 2 marked damage or inhibition of growth 3 heavy damage and only deficient development or only 50 emerged plants partially destroyed after germination or only 25% emerged plants completely dead or not emerged.

The active compounds, the amounts applied and the re (10) Post-emergence test.

Solvent: 5 parts by weight acetone Bmulsifier: 1 part by weight 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 stated amount of emulsifier is added and the concentrate is then diluted with water to the desired concentration.

Test plants which have a height of about 5-15 cm. are sprayed with the preparation of the active compound until just dew moist. After three weeks, the degree of damage to the plants is determined and characterised by the values 0-5, which have the following meaning: 0 no effect l a few slightly burnt spots 2 marked damage to leaves 3 some leaves and parts of stalks partially dead 4 plant partially destroyed plant completely dead.

The active compounds, their concentrations and the results obtained can be seen from the following Table 2: (10) 30584/2 30584/2 ^

Claims (1)

1. CLAIMS 1. A herbicidal composition containing as active ingredient a carboxylic acid (l,2,4^thiadlazol 5-yl)-amide having the formula in which R is alkyl with 1-4 carbon atoms, haloalkyl with 1-4 carbon atoms, alkoxy with 1-4 carbon atoms or phenoxy* and R* is alkyl with 1-4 carbon atoms or phenyl, in admixture with a solid diluent or carrier or in admixture with a liquid diluent or carrier containing a surface-active agent. 2» A composition according to Claim 1 containing from 0.1 to 9 $ of the active compound, by weight*" 3· A method of killing weeds which comprises applying to the weeds or to a weed habitat a ©rboxylic acid amide of formula (1) in Claim 1 alone or in the form of a composition as defined in Claim 1. 4· A method according to Claim 3 in which the active compound is applied after emergency of the weeds and a composition is used containing from 0.1 to 5$ of the active compound by weight. 5. A method acoording to Claim 3 in which the active compound is applied before emergence of the weeds and in an amount of 1 to 50 kg per hectare. 6· A method according to any of Claims 3 to 5 in which the carboxylic acid amide is one of those hereinbefore mentioned in Example A or B. 30534/2 - 16 + 7β method. of defoliating plants which comprises: applying to the .plants' a carboxylic acid amide of formula' (l) in Claim 1 alone or in the form of a composition according to Claim.1. 8. Crops protected from damage by we'eds by being grown in areas in which immediately prior to and/or during the time of growing a carboxylic acid amide of formula !(l) in Claim 1 was applied alone or in the form of a composition according to Claim 1. 9. Carboxylic acid (1, 2, 4-thiadiazol*r5-yr)-amides of the formula (l) in Claim.1 in which R is haloalkyl with 1-4 carbon atoms, alkoxy with 1-4 carbon atoms or phenoxy, and R' is alkyl with.1-4 carbon atoms or jtenyl. ' , 10. · Carboxylic acid amides .according to Claim'9 in which R io haloalkyl with 1-2 carbon atoms whic contains 1-4 atoms of chlorine fluorine and/or bromine, or alkoxy with 1-2 carbon atoms or phenoxy and R' has the same meaning as in Claim 9· 11. he carboxylic acid amide of the. formula: '' 30584/2 - 17. The carboxylic acid amide of the formula · The oarboxylic acid amide of the formula:- The carboxylic acid amide of the formula: The carboxylic acid, amide of the formula: (16) . The carboxylic acid amide of the formula: -KH-CO-C ? A rocess according to Claim 19 in which the reaction is 30584/2 19 - Λ process according to Claim 19 or 20 in which the reaction is carried out in the presence of an inert solvent, or in the case of (b), in the presence of an excess Of the acid anhydride (4), 22* A process according to Claim 19 (a) in which the acid binder is an alkali metal hydroxide, alkali metal carbonate or tertiary amine, 23· A process for the production of carboxylic acid amides according to Claim 9 substantially as hereinbefore described in Example 1 or 2· 24. - Carboxylic acid amides according to Claim 9 whenever prepared by a process according to any of Claims 19 to 23. DR.REINHi B : I