CA1084942A - Dithiophosphoryloxy-acetic acid anilide, a process for its preparation and its use as a herbicide - Google Patents

Abstract

Abstract The present invention relates to the novel O-ethyl-5-n-propyl-dithiophosphoryloxy-acetic acid N-methylanilide of the formula

Description

~ ~084942 . - 1 - Type Ia The invention relates to O-ethyl-S-n-propyl-dithio-phosphoryloxy-acetic acid N-methylanilide, which is new, to , a process for its preparation and to its use as a herbicide.
: It is known that certain phosphoryloxy-acetic acid amides, for example O-n-butyl-S-methyl-thiophosphoryloxy-- acetic acid N-methylanilide, have herbicidal properties (see DE-OS (German Published Specification) 2,647,568).
However, the action of the known compounds is not completely satisfactory; in particular, no satisfactory 10 action can be achieved against varieties of bedstraw (Galium sp.) with low active-compound concentrations and when low amounts are used.
The present invention now provides, asa newcompound, O-ethyl-S-n-propyl-dithiophosphoryloxy-acetic acid N-methyl-15 anilide, which has the formula S CH
C2H5\ p_o-cH2-co-N ~ (I).
n~C3H7S J

The invention also provides a process for the pre-paration of the compound of the formula (I), in which O-ethyl-S-n-propyl-dithiophosphoric acid chloride, of the 20 formula C H o S
n ~ 7 (II), !.
is reacted with hydroxyacetic acid N-methylanilide, of the formula -CH2-CO-N- ~ (III), ,, ~; Le A 19 182 ~

~ ' '

- 2 -ir appropriate`in the presence Or an acid acceptor and if appropriate in the presence Or a diluent.
The present compound,O-ethyl-S-n-propyl-dithiophos-phoryloxy-acetic acid N-methylanilide, is distinguished by a high herbicidal activity.
Surprisingly, the new compound (I) exhibits a con-siderably more powerful action against varieties of bed-straw (Galium sp.) than other compounds of analogous struc-ture and the same type of action which are known from the state of the art, and is tolerated by useful plants, for example wheat, soya, beet and maize.
The reaction which proceeds in the preparation of the new compound (I) can be outlined by the following equation:

C2HS \ ~-Cl ~ HO-CH2-CO-n~C3H7S /

2 5 / p_o-CH2-cO-N ~

The O-ethyl-S-n-propyl-dithiophosphoric acid chloride (II) to be used as a starting substance i8 known (see DE-AS (German Published Specification) 2,642,982).
The hydroxyacetic acid N-methylanilide (III) also to be employed as a starting compound is likewise known (see DE-OS (German Published Specification) 2,647,56~8).
The process for the preparation of O-ethyl-S-n-propyl-dithiophosphoryloxy N-methylanilide according to the invention is preferably carried out using a suitable solvent or diluent. Possible solvents and diluents are virtually any of the inert organic solvents. These include, as preferences, aliphatic and aromatic, optionally chlorinated .
Le A 19 182 1~84942 hydrocarbons, such as benzine, benzene, toluene, xylene, methylene chloride, chloroform, carbon tetrachloride, chloro-benzene and o-dichlorobenzene; ethers, such as diethyl ether, dibutyl ether, tetrahydrofuran and dioxan; ketones, such as acetone, methyl ethyl ketone, methyl isopropyl ketone and methyl isobutyl ketone; nitriles, such as aceto-nitrile and propionitrile; and alcohols, such as methanol, ethanol and n- and iso-propanol. If appropriate water may be used as a further solvent component.
Any of the customary acid-binding agents can be used as the acid acceptor . Alkali metal hydroxides, carbonates and alcoholates, such as sodium hydroxide and potassium hydroxide, sodium carbonate and potassium carbonate and sodium methylate and ethylate and potassium methylate and ethylate, and furthermore aliphatic, aromatic or hetero-cyclic amines, for example triethylamine, trimethylamine, dimethylaniline, dimethylbenzylamine and pyridine, have proved particularly suitable.
The reaction temperature can be varied within a sub-stantial range. In general, the reaction is carried out at from -10 to +100C, preferably at from 0 to 80C. In general, the process according to the invention is carried out under normal pressure.
The starting compounds are usually employed in equi-molar amounts for carrying out the process according to the invention. An excess of one or other of the reactants brings no substantial advantages. In general, the reaction i~ carried out in a suitable diluent in the presence of an acid acceptor, and the reaction mixture is stirred at the required tem~erature for several hours. m ereafter, the reaction mixture is poured into water and extracted with a water-immiscible solvent, for example toluene, the mixture is washed with dilute sodium hydroxide solution and then with water and the organic phase is dried and filtered. m e oily product which remains after distilling Le A 19 182 ~084g4Z

off the solvent in V~cuo cannot be distilled without decomposition, but it can be freed from the last volatile constituents by so-called "incipient distillation", that is to say by prolonged heating to moderately elevated tempera-tures under reduced pressure, and can be purified in thismanner. The refractive index is used for its characterisation.
The active compound according to the invention in-fluences plant growth and can therefore be used as a defoliant, desiccant, agent for destroying broad-leaved plants and germination inhibitor, and especially as a weed-killer. By weeds, in the broadest sense, there are meant all plants growing in locations where they are undesired.
Whether the substance according to the invention acts as a total or selective herbicide depends essentially on the amount used.
The active compound according to the invention may be used, for example, to combat the following plants:
dicotyledon weeds of the genera Sinapis~ Le-pidium, Galium, Stellaria, Matrica~ia, Anthemis, GaIinsoga, Chenopodium, Urtica, Se~ecio, Amaranthus, Portulaca, Xanthium, Convolvulus, I~omoea, Polygonum, Sesbania, .
Ambrosia, Cirsium, Ca~duus, Sonchus, RoriPpa, Rotala, Lindernia, Lamium, Veronica,-Abutilon, Emex, Datura, Viola, Galeopsis, Papaver, Centaurea and Solanum; and monocotyledon weeds of the genera Echinochloa, Setaria, Panicum, Digitaria,-Phleum, Poa, Fes-tuca, Eleusine, rac~ia~ia, Lolium, B~omus, Avena,-Cyperus, -So~ghum, ~gropyron, Cy~odon, Monocha~ia, Fim~ristylis, Sa~ittaria, Eleocha~is, Sci~pus, ~aspalum, Ischaemum, Spenoclea, Dactyloctenium, Agrostis, Alopecu~us and Apera.
The active compound according to the present invention may be used, for example, as a selective herbicide in the following cultures:

Le A 19 182 ` i~84942 dicotyledon cultures of the genera~ Gossypium~
Glycine, Beta, Daucus, 'Phaseo~us, Pisum, Solanum, Li~um, -Ipomoea, ~icia, Nicotiana, Ly'cope~sicon~ ~rachi Brassica, Lactuca, Cucu~is and Cucurbita; and monocotyledon cultures of the genera Oryza, Zea, Triticum, Hordeum, Avena, Secale, Sor~hum, Panicum, sacchaFum~ Ananas, Asparagus and Allium.
However, the use of the active compound according to the invention is in no way restricted to these genera but also embraces other plants, in the same way.
Depending on the concentrations, the compound can be used for the total combating of weeds, for example on industrial terrain and railway tracks and on paths and squares with or without trees. Equally, the compound can be employed for combating weeds in perennial cultures, for example afforestations, decorative tree plantings, orchards, vineyards, citrus groves, nut orchards, banana plantations, coffee plantations, tea plantations, rubber plantations, oil palm plantations, cacao plantations, soft fruit plantings and hopfields, and for the selective combating of weeds in annual cultures.
The active compound according to the invention is preferably used for selectively combating weeds in various useful crops, such as, for example, wheat, soya, beet and maize. It is particularly suitable for combating varieties of bedstraw (Galium sp.).
The active compound can be converted into the customary formulations, such as solutions, emulsions, wettable powders, suspensions, powders, dusting agents, pastes, soluble powders, granules, suspension-emulsion concentrates, natural and synthetic materials impregnated with active com-pound, and very fine capsules in polymeric substances.
These formulations may be produced in known manner, for example by mixing the active compound with extenders, that iæ to say liquid or solid diluents or carriers, optionally Le ~ 19 182 --" iO8494Z
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 used as auxiliary solvents.
As liquid 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 dimethyl-sulphoxide, as well as water.
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 ~uch 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, polyoxyethylene-fatty alcohol ethers, for example alkylaryl polyglycol ethers, alkyl sulphonates, alkyl sulphates, aryl sul-phonates as well as albumin hydrolysis products. Dis-persing agents include, for example, lignin sulphitewaste liquors and methylcellulose.

Le A 19 182 Adhesives such as carboxymethylcellulose and natural and synthetic polymers in the form of powders, granules or latices, such as gum arabic, polyvinyl alcohol and polyvinyl acetate, can be used in the formulations.
It is possible to use colorants such as inorganic pigments, for example iron oxide, titanium oxide and Prussian Blue, and organic dyestuffs, such as alizarin dyestuffs, azo dyestuffs or metal phthalocyanine dyestuffs, and trace nutrients, such as salts of iron, manganese, - 10 boron, copper, cobalt, molybdenum and zinc.
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 compound according to the invention, as such or in the form of its formulations, can be combined with other herbicidal active compounds to intensify and supplement its action spectrum, depending on the intended use, finished formulation or tank mixing being possible.
Mixtures with other active compounds, such as fungicides, insecticides, acaricides, nematicides, bird repellants, growth factors, plant nutrients and agents which improve soil structure, are also possible.
The active compound can be used as such, in the form of its formulations or in the use forms prepared therefrom, such as ready-to-use solutions, emulsions, suspensions, powders, pastes and granules. It may be used in the customary manne~, for example by spraying, a~omising, dusting, scattering and watering.
The active compound according to the invention can be applied either before or after emergence of the plants.
It is preferably used before emergence of the plants, that is to say by the pre-emergence method. It can also be incorporated into the soil before sowing.
The amount of active compound used can vary within a substantial range. It depends essentially on the nature Le A 19 18~

of the desired effect. In general, the amounts used are from 0.1 to 10 kg of active compound per hectare, prefer-ably from 0.1 to 5 kg/ha.
The active compound according to the invention has not only herblcidal properties, but furthermore also an insecticidal activity; it can thus be used, for example, against pests harmful to health and pests of stored products.
The present invention also provides a herbicidal composition containing as active ingredient the compound of the present invention in admixture with a solid 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, the compound of the present invention alone or in the form of a composition containing as active ingredient the 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 the compound of the present invention was applied alone or in admixture with a diluent or carrier.
The herbicidal activity of the compound of this invention is illustrated by the following biotest Example.
The known comparison compound is identified as follows:

4 9 ~P-0-CH2-C0-N - ~ - (A) 3o (0-n-butyl-S-methyl-thiophosporyloxy-acetic acid ~-methyl-anilide).

Le A 19 182 _ 9 _ 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:
0% = no action (like untreated control) 100% = total destruction The active compounds, the amounts applied and the results can be seen from the table which follows:

Le A 19 182 .

iO8494Z

,.1 88 ~1 tdl O O ,0~ ~0 h ~ ¦ 8 0 o ~ o o o O IL) >, N
~1 rO
td ~ td E~
~D O

r~
O
O C) O Ir~ O u~
O ~ ~ ~ U~ N
~3 c) O b~
td ~ ~ _ ~
C~ O
C) Le A 19 1 B2 Preparative Example C H o S CH ~ (I)

3.3 g (o.o6 mol) of potassium hydroxide were initially introduced into 100 ml of iso-propanol, and 8.2 g (0.05 mol) of hydroxyacetic acid N-methylanilide and 11.9 g (0.05 mol) of 0-ethyl-S-n-propyl-dithiophosphoric acid chloride (91.4% pure) were added at an internal temperature of between 0 and 5C. The reaction mixture was stirred at 5C for 30 minutes and at room temperature for 2 hours, it was then poured into 250 ml of water and extracted twice with 150 ml of toluene each time. The organic phase was washed twice with 5 ml of 2 N sodium hydroxide solution each time and then with water until neutral, dried over sodium sulphate and filtered, the filtrate was concen-trated at a bath temperature of 40C and the residue was subjected to incipient distillation at 40C using a vapour pump. 16 g (92.4% of theory) of 0-ethyl-S-n-propyl-dithiophosphoryloxy-acetic acid N-methylanilide were obtained as a pale yellow oil with the refractive index nD6: 1.5495.

Le A 19 182

Claims (6)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. O-Ethyl-S-n-propyl-dithiophosphoryloxy-acetic acid N-methylanilide, of the formula, (I).

2. A process for the preparation of the compound according to claim 1, characterised in that O-ethyl-S-n-propyl-dithiophosphoric acid chloride, of the formula (II), is reacted with hydroxyacetic acid N-methylanilide, of the formula (III).

3. A method of combating weeds which comprises applying to the weeds, or to a habitat thereof, a herbicidally effective amount of the compound O-ethyl-S-n-propyl-dithiophosphoryloxy-acetic acid N-methylanilide.

4. A method according to claim 3 wherein the compound is applied in the form of a composition containing said compound as active ingredient in admixture with a suitable diluent or carrier.

5. A method according to claim 3 or 4 in which the compound is applied to an area of agriculture in an amount of 0.1 to 10 kg per hectare.

6. A method according to claim 3 or 4 in which the compound is applied to an area of agriculture in an amount of 0.1 to 5 kg per hectare.