IL33765A - N-phenylureas,their preparation and herbicidal compositions containing them - Google Patents

Description

33765 2 N-phenylureas, their preparation and herbicidal compositions containing them BATBR AG Ct32055 The present Invention relates to certain new K-arylureas, to a process for their preparation and to their use as herbicides.

It is known that N-aryl-N'-alk lureae can be used as herbicides. It is also known that N- -trifluorome hylmerca to-phenyl)-EP ,ΕΡ-dimethylurea can be used as a selective herbicide* for example in cereals (cf. Belgian Patent 719350), Another group of herbicldally active compounds, i.e. Ή*-monoalkyl and N' jN'-dialkyl Jtf-phenyl ureas haj* been claimed in Israel Patent 27751. In these compounds the phenyl radical is substituted, among others, with one or two haloalfcya/ groups and may bear In addition one or more halo subetltuents.

The present invention is concerned with a certain group of the above mentiaed urea compounds which have been claimed generally in the Israeli specification aforesaid but have not been mentioned specifically therein.

These new K-pieaylureas have the general formulat in which and Xg are trj^uoromethoxy, chlorine or hydrogen, provided that at least one'them is trifluoromethoxyi is hydrogen or alkyl with 1-4 carbon atoms % and R2 is alkyl with 1-4 carbon atom The active compounds according to the invention exhibit a higher herbicldal activity than the chemically most similar active compounds of the same type of activity specifically mentioned in the Israel Patent 27751, as will'be shown below.

The invention also provides a process for the production of t..,'·. N-phenylureas of formula (l) above in which an isocyanate of the formul t is reacted with an amine of the formula: in the presence of a solvent.

When 4-trifluoromethoxyphenylisocyanate and dimethylamlne are used as starting materials, the reaction can be represented by the following formula scheme» The starting materials of formulae (2) and (3) are known* As examples of ieooyanates of formula (2) there may be mentioned} 3-chloro-4-trifluoromethoxyphenylisocyanate, 3-trifluoromethoxyphenyl-isocyanate and 3-trlfluorometh033y«4-chlorophenylisocyanate.

Particularly suitable amines are methylamine, dlmethylaraine, methylethylamine, butylamine and methylbutylamine.

As solvent (which term includes mere diluents), water and inert organic solvents are suitable. These include, in particular, ethers, such as dioxan and diethyl ether; hydrocarbons, such as benzene; and chlorinated hydrocarbons, such as chlorobenisene· The reaction temperatures can be varied within a fairly wide range; in general, the work is carried out at 10~80°C, preferably at Approximately equimolar amounts of isocyanate and amine are in principle used in the process, but an excess of the amine does no harm. Working up may be effeoted in customary manner.

The active compounds exhibit a strong herbicide! potency and oan herbicidal agents depends essentially on the amount applied. '9' -- 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), smallflower Galinsoga (Galinsoga), fathen (Chenopodium), stinging nettle (Urtica), groundsel (Senecio), cotton (Gossypium), beets (Beta), carrots (Daucus) ,: beans (Phaseolus), potatoes. (Solanum, coffee (Coffea); monocotyledons, such as timothy (Phleum) , bluegrass (Poa) , fescue (Festuca) , .goosegrass (Eleusine), foxtail (Set-aria) , ryegrass (Lolium), cheat (Bromus), barnyard grass (Echin-ochloa) , maize (Zea), rice (Oryza), oats (Avena), barley (Hordeum) , wheat (Triticum), millet (Panicum), sugar cane (Saccharum).

The active compounds are preferably used as selective herbicides. They show agood selectivity when applied before and after emergence of the cultivated plants in. cereal cultivation, partiaiarly in wheat and maize cultivation, and can also be used for weed control in cotton and parrots.

The active compounds according to the present invention can be converted into the usual formulations, such as solutions., emulsions, suspensions, powders, pastes' and granulates. These may. be produced in known manner, for example by mixing 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 or benzene, chlorinated aromatic hydrocarbons, "such as chlorobenzehes, paraffins, such as mineral' oil fractions, alcohols, such as methanol or butanol, or stron l olar solvents such as dimeth l formamide or di As solid diluents or carriers, there are preferably used*, ground natural minerals, such as kaolins, clays, talc or chalk,1 or ground synthetic minerals,, such as highly-dispersed silicic acid or silicates.

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

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

The active compounds may be applied as such, or in the . form of their formulations or of the application forms prepared therefrom, suoh as ready-to-use solutions, emulsions, suspensions, powders, pastes and granulates. Application takes place in the usual manner, for example by dusting, spraying, squirting, watering or scattering.

Application can be effected before as well as after emergence.

The amount of active compound applied may vary within fairly wide ranges. It depends essentially on the nature of the desired effect.

In general, the amounts applied are from 0.25 to 15 kg of active compound per hectare, preferably 0.5 to 10 k per hectare.

The invention therefore provides a herbicidal ' composition containing as active ingredient a compound according to the invention in admixture with a solid diluent or carrier or in admixture with a liquid diluent or carrier containing a surface-active agent. .weeds which comprises applying to the weeds or a weed habitat a compound according to the invention alone or in the form of a composition containing as active ingredient a compound according to the invention in admixture with a solid or liquid diluent or carrier.

The invention also 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 according to the invention was applied alone or in admixture with a solid or liquid diluent or carrier.

The invention is illustrated by the following test Examples A-D and preparative Examples 1. and 2.

■ Example A , Pre-emergence test Solvent: 5 parts by weight acetone Emulsifier: 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.

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 3 heavy damage and only deficient development or only 50$ emerged ' plants partially destroyed after germination , or only "· ; " 259^ emerged plants completely dead or not emerged.

The active compo-unds, the amounts applied and the results obtained can he seen from Table A, · Example B- The tests- of Example A were repeated using' other compounds. The resits are given in Table B, The last of these compounds namely compound (8) was compared with one of the most closely related compounds mentioned in Israel Patent 27751.

Example C Post-emergenoe-.teBt Solvent: 5 parts by weight acetone Emulsifitr : .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 oompound such a way, that the amounts of active compound per unit area as given in the following table are used.. Depending on the concentration of the spraing liquor the amount of water ranges , from 1000 - 2000 1/ha. 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 1 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 oompounds, their concentrations and the -results obtained can be seen from Table C Example D .

The tests of Example 0 were repeated, using other oompounds.

The results are given in Table D .

The activit of compound (8) was compared with that of the most closely related compound mentioned in Israel Patent 27751. 33765/2

Claims (23)

1. N-phenylureas of the general, formula: in which and ¾2 are trifluoromethoxy, chlorine or hydrogen, provided that ;at least one of them is trifluoromethoxy,. is hydrogen or alkyl with 1-4 carbon atoms, and is alkyl with 1-4 cafbon atoms.

2. The compound of the formula:-

3. The compound of the formula:-

4. The oompound of the formula:

5. CI

6. The compound of the formula:

7. The compound of the formula:

8. The compound of the formula:-

9. The compound of the formula:-

10. A process for the production of an N-,pheriylurea according to any of claims 1-9 in which an iaocyanate of the formula:- is reacted with, an amine of the formula:- m' 1 (3) 2 in the presence of a solvent.

11.. A process according to claim 10 in which the isocyanate ia 2-chloro-4-trifluoromethoxyphenylisocyanate, 3-trifluoro-methoxyphenylisocyanate, 4-trifluoromethoxyphenylisocyanate or 3-trifluoromethoxy-4-chlorophenylisooyanate. '

12. A process according to claim 10 or 11 in which the amine is methylamine, dimethylamine or raethylethylamine .

13. A process according to any of claims 10-12 in which the solvent is an ether, a hydrocarbon or a chlorinated hydrocarbon,

14. A process aocording to any of claims 10-13 in whioh the reaction is oarried out at 10-80°0.

15. -is carried out at 20-50°C.

16. A process for the production of a compound accordin to claim 1 substantially as hereinbefore described n example 1 or 2. ·. -■■ .

17. ' Compounds according to; claim 1 whenever prepared b a process according to any of claims 10-16.

18. A herbicide,! composition containing as active ingredient a compound according to any of claims 1-9 or 17 in admixture with a solid diluent or carrier or in admixture with a liquid diluent or carrier containing' a surface-active agent*

19. A composition according to claim 18 containing from 0.1. to 959¾ by weight of the active compound.

20. A method of combating weeds which comprises applying, to the weeds or a weed habitat a compound according to any of claims 1-9 or 17 alone or in the form of a composition containing as active ingredient a compound according to any of claims 1-9. or 17, in admixture with a solid or liquid ; diluent or carrier. - L, ■

21.' A method according to claim 20 in which the active com- pouidfe applied to. an area of agriculture in an amount from .0.25 to 15 kg per hectare.

22. A method according to claim 20 or 21 in which the active compound is applied to an area of cultivation of cereals, cotton or carrots, ■ ■

23. Crops protected from damage by weeds by being grow in, areas in which, immediately prior to and/or during the '.··. time of .the growing a compound according to any of claims •1-9 or 17 was applied alone or in. admixture with a solid or •liquid diluent or' carrier. For the Applicants ■ '·-.