DE1949289A1 - Method and means for selective weed control in crops of useful plants - Google Patents

Description

Methods and means for selective weed control
in crops of useful plants

The invention relates to a method and a herbicidal agent for
Weed control using an active ingredient made from amides

of aryloxyalkanecarboxylic acids according to the following formulas
A.

O - R - CO -

O - R - CO - N;

where R = a straight or branched alkoyl radical with 1 to 5 Carbon atoms,

R ^f = hydrogen or an optionally halogenated alkoyl radical with 1 to 5 carbon atoms,

0098 36/2204

original inspected

" ² " 1943280

R "= an alkoyl or an optionally halogenated alkenyl radical with 1 to 5 carbon atoms,
A = a halogen,

B = an alkoyl radical with 1 to 3 carbon atoms, optionally May carry halogenated substituents, m and η = integers from 0 to 4 with the proviso that m or η or m + η = 2 and the substituents not in the 2,4-position stand in the phenolic nucleus.

The use of aryloxyalkanecarboxylic acids as selective herbicides and certain derivatives thereof have been known for a long time.

The first work in this area was carried out around 1940 and resulted in numerous herbicides that were particularly useful against Dicotyledones adventices in grass crops, especially in cereals, like wheat, barley, oats, as well as in certain tropical cultures, like rice, sugar cane or the like.

The chief compounds from this family of herbicides of practical importance are the following:

2,4-dichlorophenoxyacetic acid (2.4 D)

2-methyl-4-chlorophenoxyacetic acid (MCPA)

2,4,5-trichlorophenoxyacetic acid (2,4,5 T)

2- (2,4-dichlorophenoxy) propionic acid (dichloroprop)

2- (2-methyl-4-chlorophenoxy) propionic acid (mecoprop) 2- (2,4,5 trichlorophenoxy) propionic acid (fenoprop)

Other connections in the same family, especially those whose phenoxy radical is monosubstituted in the 4-position are also known as herbicides but have found very little practical use.

'' ORIGINAL JMSPEGTED

009836/2204

The publications about these products are extremely neat numerous and show that these compounds act like natural auxins on cell growth and cause proliferation, from where a deformation of the leaves, stems as well as an atrophy of the roots and the death of the plant originate.

Some of these auxins or "phytohormones" have selective properties equipped, so they can be used as herbicides for the post-germination treatment of crops.

For practical use, these phytohormones are seldom to be used in their acid form, but almost always as alkali salts, Amine salts, esters and unsubstituted amides (CO-NH ^).

In these different forms, the phytohormones show similar herbicidal effects, but leave the physico-chemical effects Properties, in particular their solubility and their vapor pressure, make one or the other compound of this group appear more suitable depending on the type of weed control planned.

In general, however, with regard to their effectiveness and selectivity, it can be said that these different forms are mutually exclusive are very similar.

It has now been found that the conversion of these acids into N-mono- or disubstituted amides also compounds with herbicidal properties and that the spectrum of effects is often fundamentally different from that of phytohormones, which form the starting substances.

009836/2204 _α .,., _F2CTa >

ι π / ι ..

1 9 4 3

In this way, depending on the number and position of the substituents in the aryl radical, herbicidally active substances are also obtained Compounds which can be used before the seeds come up, namely

effective against grasses and monocotyledons, i.e. applicable, as a totally effective herbicide,

effective against a large number of monocotyledons and dicotyledons, but selective against other species of these two classes, such as crucifers, in particular Tomatoes and beets, and grasses such as wheat, corn, barley, etc.

The present invention therefore constitutes an essential technical one Progress compared to the phytohormones with similar structures, due to the versatile effectiveness of the spectrum of activity of these connections.

The preparation of the substituted amides, which is the subject of Invention and whose herbicidal properties have been tested, is carried out using methods known per se, for example:

by reacting an ester of an aryloxyalkanecarboxylic acid with a mono- or disubstituted amine, by reaction of the free acid with a mono- or disubstituted amine and dehydration by means of heat the amine salt obtained,

by reacting the free acid or a salt of an aryloxyalkanecarboxylic acid with a carbamoyl halide (according to French patent 1.426.086).

ORiCHMAL ir-iSFEGTED

009836/2204

1949283

As a non-limiting selection from those to be used according to the invention Compounds with herbicidal properties can be named those with the substituents listed in the table below will:

No.

A. 2 B. H H ₂ H H 2 H H 2 H H Cl, H H 2-CH ₃ H 4-CH ₃ 3-Cl H 4-Cl H 6-Cl 2-CH ₃ 2-Cl 3-CH
3 4-Cl 3-CH
3 2,4-Cl 3-CH
3 4,6-Cl 3-CH ₃ 2.5-Cl H 2,6-Cl H 2,3,6-

R "

CH,

CH

CH

CH

CH,

CH

CH

CH,

CH

CH

CH

CH

CH

CH

CH

H
CH

CH
5

Allyl
CH ₃

CH

CH

CH

CH

^CH

CH

CH

CH

CH

CH

CH

CH

C H 2

Allyl CH ₃

CH ₃ CH ₃

CH 3

CH ₃

CH

CH 3

CH 3

CH ₃

^CH 3

CH 3

CH "

Oai <3! NAL INSPECTED

1949280

17th 2,4,5-Cl ₃ H ^CH 2 H CH ₃ 18th 2,4,5-Cl ₃ H CH
2 ^CH 3 CH 19th
20th 2,4,5-Cl ₃
2,4,5-Cl ₃ H
H CH ₂ .
^CH 2 ^C 2 ^H 5
Allyl CH
2 5
Allyl 21 2,4,6-Cl H ^CH 2 CH ₃ CH ₃ 22nd H H CH- (CH)
3 CH
3 CH ₃ 23 H 2-CH CH- (CH)
3 CH ₃ CH ₃ 24 H 3-CH ₃ CH- (CH) CH ₃ CH
3 25th H 4-CH
3 CH- (CH) CH
3 CH
3 26th H 2,5- (CH ₃ I ₂ CH- (CH) CH
3 CH
3 27 2,4-Cl ₂ 3-CH
3 CH- (CH) CH CH
3 28 4-Cl H CH- (CH ₃ ) CH CH ₃ 29 2,5-Cl ₂ H CH- (CH) CH
3 CH 30th 2,3,6-Cl ₃ H CH- (CH ₃ ) CH
3 CH
3 31 2,4,5-Cl ₃ H CH- (CH ₃ ) CH CH
3 32 2,4,6-Cl ₃ H CH- (CH ₃ ) CH ₃ CH ₃

All of these substituents refer to those of the first of the two introductory given formulas.

009836/2204

ORIGINAL SUSPECTED

1943283

Although all the compounds corresponding to these two formulas, in particular have the interesting herbicidal properties listed in the table above, but are the preferred according to the invention Substances those in which the position of the substituents in the phenyl nucleus are different from those of the classical ones Phytohormones such as 2,4-D, MCPA, 2,4,5-T and their homologs from the series of phenoxy-2-propionic acids.

More precisely, the preferred positions of the substituents are in the phenyl nucleus as follows:

with a monosubstitution in positions 2 or 3, with a disubstitution in positions 2 and 3, 2 and 5 or 3 and 5,

in the case of trisubstitution in positions 2, 3, 4 or 2, 3, 5.

It has also been found that the most effective compounds must contain an unsubstituted hydrogen atom in the alpha position to the phenyl nucleus.

The particularly interesting connections are above all

the NN-dimethylamide of (dichloro-2,5-phenoxy) -2-propionic acid the NN-dimethylamide of (methyl-3-dichloro-2,4-phenoxy) acetic acid the NN-dimethylamide of (methyl-3-dichloro-4, 6-phenoxy) acetic acid the NN-dimethylamide der4-naphthoxyacetic acid and the NN-dimethylamide of (dimethyl-2,5-phenoxy) -2-propionic acid.

The herbicidal properties of the compounds according to the invention have been demonstrated in numerous tests, which were carried out on 16 representative ones Cultivated and weed plants as well as on mono- and dicotyledons were made.

009836/2204

1 q 4 ο ο ο ο

Unless otherwise stated, the tests were carried out as follows:

The seeds of the plant species concerned were sown in pots and covered with a sufficient amount of earth to make a good one Ensure germination.

The pots were then treated with a wettable powder containing the substance which was to be tested. The dilution This powder mixture was chosen in such a way that the amount of the active component was converted to about 8 kg / ha.

35 days after this treatment, the results obtained were checked.

A comparative sample of each plant species was used in each series of experiments held aside.

The most essential plant species used for these experiments were as follows, with the letters attached being an abbreviation;

(A) = oats (Avena sativa)

(B) = wheat (Triticum vulgare) (M) = maize (Zea mays)

(Mi) = millet (Panicum miliaceum)

(O) = barley (Hordeum distichum)

(P) = Panisse (Panicum = Echinochloa crus-galli)

(R) = ryegrass (Lolium italicuin)

(V) = Vulpine (Alopecurus agrustis)

(C) = carrot (Daucus carotta)

009836/2204 originally inspected

" ⁹ " 1942203

(H) = beans (Phaseolus vulgaris)

(L) = flax {Linum usitatissimum)

(N) = turnip (Brassica napus)

(Po) = peas (Pisum sativum)

(S) = buckwheat (Polygonum fagopyrum)

(Tom) = tomato (Lycopersicum esculentum)

(Tou) = sunflower (Helianthus annuus)

The variety of possible uses of the inventive Compounds results from the following examples, which at the same time a concept of the spectrum of activity of some of the compounds given in the table above and used for herbicidal purposes.

example 1

The connection no. 1 is completely selective for grasses such as maize, and in dicotyledons such as tomatoes, peas, beans, flax and turnips, while it completely destroys grasses or greatly destroys their growth effective inhibitors, for example from millet and ryegrass. The degree of destruction is between 80 and 100%, which is referred to below as "reliably effective".

Example 2

The connection no. 3 is completely selective of crops such as tomato, sunflower, beet, and flax while being effective on dicotyledons, such as carrots, and grasses, such as millet, panissa, ryegrass and Vulpine.

Example 3

The connection no. 5 is completely selective for crops such as tomato, Sunflower, flax, and bean, while effective on millet, panissa, ryegrass, and vulpino. .

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1943280

Example 4

The connection no. 6 is completely selective on the crops of tomato, buckwheat, pea, beet, flax and bean while they are is effective against millet and panissa.

Example 5

The connection no. 8 is a herbicide with little selective effectiveness, since the dose used is effective against grasses, wheat, millet, paniss and vulpine as well as against dicotyledons, such as Carrots, beans, flax, beets, peas and tomatoes.

Example 6

Connections No. 10 and 12 are selective for cultures of dicotyledons, like tomato, and grasses like wheat and corn, while they are effective against certain grasses like millet, panissa, ryegrass and vulpine and on dicotyledons such as carrot and flax.

Example 7

The connection no. 13 is selective on beet and peas and effective on wheat, millet, panissa, rai gras and vulpine. It is therefore particularly useful for controlling grasses in crops of Dicotyledons.

Example 8

Compounds Nos, 17 and 18 are effective in one application from 8 kg / ha on all types of the tested dicotyledons as well as on certain grasses such as millet and panissa. With lesser ones In doses, they retain excellent effectiveness on the dicotyledons and be selective on grasses, such as wheat.

009836/22 04 originally inspected

1943283

Example 9

The NN-dirnethylamide of (/ 5-naphthoxy) -2-propionic acid is complete selectively on grasses, such as maize, or on Dico.tyledone, such as tomatoes, and effective on grasses such as oats, millet, panissa, ray-grass and vulpine as well as dicotyledons such as carrots, beans and peas.

Example 10

This example shows one of the most essential features of the invention, i.e. the significant difference in herbicidal effectiveness between the phytohormones mentioned, which are used in the form of their unsubstituted amides, and the compounds according to the invention, namely the N-mono- or NN-dialcoylated amides.

These differences were determined by systematic comparative experiments, the unsubstituted amide being a specific acid and the corresponding NN-di-substituted amide was used. the The results are compiled in the following table:

substance
8 kg / ha A. B. M " Wed O P. Type of trial plants V C. H L. N Po S. Tom Tou I. 0 0 70 0 15th R. - 100 100 90 95 100 60 70 50 I ' 100 75 100 98 55 85 - 95 40 0 0 95 20th 0 0 II 5 20th 0 85 5 70 95 85 100 100 95 98 100 100 30th 90 II ¹ 85 60 60 100 100 95 15th 100 100 15th 0 0 85 0 0 0 III 0 0 0 100 0 50 100 95 100 100 100 100 100 90 60 90 III ¹ 100 95 100 100 100 100 70 100 100 5 15th 0 0 70 0 0 100

009836/2204

ORIGINAL

I = phenoxy-2-propionamide

Γ = phenoxy-2-NN-dimethyl-propionamide (no.22 of the table) II = (methyl-2-phenoxy) -2-propionamide

II '= (methyl-2-phenoxy) -2-NN-dimethyl-propionamide (no 23 of the table) III = (dichloro -2, 5-phenoxy) -2-propionamide
III '= (dichloro-2, 5-phenoxy) -2-NN-dimethyl-propionamide (no.29 of the table)

Example 11

This example shows the superiority of the preferably substituted Compounds as mentioned above versus derivatives with a 2,4-disubstituted phenol nucleus, as described, for example are in Australian Patent No. 49-319 from BOOTS PURE DRUG, with mono- and disubstituted amides of (methyl-2-chloro ~ 4-phenoxy) acetic or propionic acids are mentioned.

substance
8 kg / ha A. B. M. Type of test plants P. R. V H L. N Po S. Tom Tou IV 0 0 0 O 20th 20th 40 0 0 0 0 20th 0 0 V 0 0 0 0 85 15th 70 15th 30th 98 100 25th 25th 0 VI 0 0 0 0 20th 30th 0 15th 50 65 100 60 0 0 VII 100 80 0 0 100 100 100 0 0 0 0 0 0 0 VIII 100 95 100 100 100 100 100 5 15th 0 0 0 70 5 100

IV = dimethyl-2,4-phenoxy) -2-NN-dimethyl-propionamide V = (methyl-2-chloro-4-phenoxy) -2-NN-dimethyl-propionamide (BOOTS PUREDRUG)

VI = (2,4-dichlorophenoxy) -2 -NN-dimethyl-propionamide VII = (2,5-dimethyl-phenoxy) -2 -NN -dimethyl-propionamide (ex. 26 tab.) VIII = (2, 5-dichloro-phenoxy) -2-NN-dimethyl-propionamide (ex. 29 tab.)

This example clearly shows that in the case of disubstituted amides with substituents of the phenol nucleus according to the usual herbicidal phytohormones, i.e. in

009836/2204

0RK3IWÄL INSPECTED

1 QAO O G Π

I Ό τ ν .; CU ν /

2,4-position, as in 2,4-D, the dichloroprop, the MCPA and the Mecoprop, compounds are obtained that

are little or not effective (substance IV) or have an effectiveness similar to the phytohormones η, i.e. They are especially effective against dicotyledons (substances V and VI), whereas good effectiveness is found in the case of those according to the invention Compounds (Nos. 26 and 29), whereby these can be used against grasses in cultures of dicotyledons.

Example 12

The product no. 29, whose herbicidal effectiveness was tested at 8 kg / ha according to the previous example, is also lower Cans has been tested with the following results:

At 2 kg / ha this product is selective on dicotyledons such as beetroot, beans, flax, beet, buckwheat, and tomato Sunflower, and 100% effective on all tested grasses.

At 1 kg / ha the selective effect is clearly retained and the Effectiveness is still complete against ryegrass, vulpine, barley, millet and oats, while they are still relatively high with 75-85% destruction is effective on wheat and panis.

This connection is therefore particularly interesting for grass control in very numerous cultures of dicotyledons.

Example 13

This example proves that mixtures of several according to the invention Compounds can develop a particularly interesting effectiveness in certain cases, in contrast to the application of the individual connections cannot be foreseen.

^009836/2204 ^ pa

1949280

This is the case, for example, when using a mixture, with which 4 kg / ha of compound no. 12 and 4 kg / ha of compound no. are applied, whereby herbicidal effects are obtained which are different from the sum of the herbicidal effects which each of the compounds used alone.

So, for example, is the mixture on beets, tomatoes and sunflowers completely selective, while each of the constituents alone exerts a certain herbicidal effect.

Example 14

The compounds according to the invention also formed the subject matter of experiments in the wild, to their selective and herbicidal effects to be checked under normal conditions of use.

For this purpose, the products according to the invention were in the form of a moistenable Powder used which contained 20% of the active ingredient after this mixture for one minute in one Knife mill was mixed intimately. The individual components were:

Test product 20%

Calcium lignosulfate 5%

Sodium alkylarylsulfonate 1 %

Aluminum silicate 74 %

^ ₅ The wettable material obtained in this way was then diluted

Φ Pudßr to give him the appropriate concentration, with that one

^ a certain amount could be spread per hectare.

! ^? Under these conditions gave the NN-dimethyl- and -diaethylamides

¹ y? of (2 5 5-dichlorophenoxy) -2-propionic acid when used in rapeseed

complete destruction at a concentration between 1 and 3 kg / ha of the adventicids, such as vulpine, ryegrass (Lolium sp.), paturin

ORK3INAL INSPECTED

- 15 - 1949 280

(Poa annua), Agrostides (Agrostis Spica-Venti), Matricaren (matricaria sp) as well as numerous other plant species such as grasses and dicotyledons.

At all doses used, the selectivity of the product is opposite Rape completely.

The compounds according to the invention can be used in practice can be used per se in pure form, but it is expedient to use them in mixtures, which in addition to the active ingredient still contain liquid or solid carriers and various additives, as they are in this field of Pesticides are known.

The details of the preparation of these mixtures are the subject of numerous publications, in particular in the work WEED CONTROL HANDBOOK by EVANS, 5th edition, volume I ₁ page 10lff.

As far as the practical application doses are concerned, these can be wide Limits vary depending on the effectiveness of the compound in question and the weed control to be achieved, also on the stage of development of the crop and the weeds as well as on the type of soil and atmospheric conditions.

In general, doses between 0.1 and 20 kg / ha of active substance are sufficient, with an application between 1 and 8 kg / ha comes into consideration.

The type of treatment and practical application of the invention Compounds depends on the nature of the herbicidal action of the compound used bczw. Links. You are particular

009836/2204

IGINS IKSPECTH)

- 16 - 194 920

applicable for:

a pre-sowing treatment if the herbicide is selective against the the culture in question is

a treatment after the cultivation seed has emerged, but before the germination of adventices, especially if the culture is particularly resistant to subsequent treatments,

if necessary also a treatment after the emergence of the culture and the adventices.

This is because they have a large number of the compounds described with a subsequent treatment a remarkable herbicidal activity, both against grasses and against dicotyledons.

The connections according to the invention can be used either alone or in Mix-ung with other herbicidal compounds are used, either of the same chemical class or of a different one Belong class, such as substituted ureas, triazines, ether oxides of substituted diphenyls, etc., whereby whose spectrum of activity can be broadened and completed.

They can also be used with so-called synergists who are suitable are to increase the effectiveness of the compounds in low doses.

Finally, they can also be used in combination if necessary with fungicides, insecticides and nematocides, especially with those which are effective against soil pests, so that a culture can receive a mixed treatment in one operation.

009836/2204 "ordinal inspected

Claims (1)

PATENT CLAIMS 1. A method for selective weed control in crops of useful plants, characterized in that the soil is treated with an effective amount of a herbicidal agent, which contains one or more compounds according to the following formulas as active ingredient, before or after the seeds have sprouted:
A. O - R - CO - N: O - R - CO - N; where R = a straight or branched alkoyl radical with 1 to 5 Carbon atoms, R ¹ = hydrogen or an optionally halogenated alkoyl radical with 1 to 5 carbon atoms, R "= an alkoyl or an optionally halogenated alkenyl radical with 1 to S carbon atoms,
A = a halogen, B = an alkoyl radical with 1 to 3 carbon atoms, which can optionally carry halogenated substituents, m and η = integers from 0 to 4, provided that m or η or m + η = 2 and the substituents are not in 2,4- Position in the phenolic nucleus. .1 Herbicidal agent for carrying out the method according to claim 1, characterized by an active ingredient composed of one or more compounds according to the following formulas: 0098 36/220 4 ■;:. "ECTED - ie - 1943280 O - R - CO - N O - R - CO - N Il where R = a straight or branched alkoyl radical with 1 to carbon atoms ^ R ¹ = hydrogen or an optionally halogenated alkoyl radical with 1 to 5 carbon atoms, R "= an alkoyl or an optionally halogenated alkenyl radical with 1 to 5 carbon atoms, A = a halogen , B = an Alkoylradikal with 1 to 3 carbon atoms, which optionally May carry halogenated substituents, m and η = integers from 0 to 4 with the proviso that m or η or m + η = 2 and the substituents not in the 2,4-position with a phenolic nucleus. 003836/2204 rk?. = * al -! SF