DE2405510C2 - α-Halo-acetanilides and herbicidal compositions containing these compounds - Google Patents

Description

2. N-α-Chloroacetyl-N- (1,3-dioxolan-2-ylmethyl) -2-methyl-5-chloroaniline.

3. Herbicidal compositions containing a compound according to claim 1 or 2 and one Inert carrier.

The invention relates to a-halo-acetanllde of the general formula I Z ¹ —CH ₂

_R 2 / I

J CH ₂ -CH (CH ₂ ) ,,

/ ~ \ - NZ ² —CH ₂ CD

^ = T \

JL C-CH ₂ -XI

^R I!

ο I

wherein R ¹ and R ² are each, independently of one another, an alkyl group having 1 to 4 carbon atoms, X is halogen, Z ¹ and Z ^{2 are,} independently of one another, oxygen or sulfur and m is an integer from 0 to 2.

The invention relates to welter N-a-chloroacetyl-N-O.S-dloxoIan ^ -ylmethyO ^ -methyl-S-chloranilln and herbicides Compositions containing these compounds and inert carriers.

The compounds according to the invention are suitable as herbicides and are particularly useful for control grassy weeds.

α-Halo-acetanilides with herbicidal activity are known. Among the main commercial products of this A class of compounds belongs to alachlor, the N-a-chloroacetyl-N-methoxymethyl ^ o-diethylanllln, which is mainly known as Soil herbicide is used before sprouting and in cotton, mals, soybeans, and tomatoes Peanuts acts selectively against grasses and broad-leaved weeds (see R. Wegler, Chemie der Pflanzenschutz- and Pest Control, Vol. 5, pp. 247-258, Springer-Verlag, Berlin 1977).

There are also various homologues of alachlor known, which differ from the latter through higher alkyl and alkoxy groups or by other halogens as substituents.

Such homologues of alachlor are described, for example, in A. S. Tahorl, Pesticide Chemistry, Herblcides, Fungicides, Formulation Chemistry, Vol. V, pp. 41-64, Gordon and Breach Science Publ., New York (1972). '

Although these known herbicides are able to completely destroy the most common weed species, but at the same time they impair the growth of useful plants in undesirable catfish.

The invention is based on the object of creating new herbicides which have at least the same effectiveness to the weeds affect the useful plants to a lesser extent than those mentioned known herbicides.

This object is achieved by providing the compounds according to the invention and those containing them Herblzlden compositions dissolved.

Typical representatives of the compounds of the general formula I according to the invention, in which X is preferred Means chlorine or bromine, are N-cr-chloroacetyl-N- (1,3-dloxolan-2-ylmethyl) -2,6-dlmethylanllln, N-a-chloro- acetyl-N- (1,3-dloxolan-2-ylmethyl) -2,6-dläthylanllln and N-α-chloroacetyl-N- (1,3-dloxepan-2-ylmethyl) -2,6-dläthylanllln.

The compounds according to the invention can be prepared by reacting a compound of the general formula II

Z ¹ -CH ₂

/ I

N-CH ₂ -CH (CHj) ₁ ,

i \ I

HZ ² -CH ₂

(Π)

wherein R ¹ , R ² , Z ', Z ² and m have the meanings given above, with a «-haloalkanyl chloride of the general formula III

Il

Cl-C-CH ₂ -X (DD

wherein X is as defined above. The reaction is carried out by reacting a compound of the formula II with a compound of the formula III in an inert organic reaction medium, e.g. B. Dloxan, In the presence of an acid acceptor, e.g. B. of an alkali metal carbonate or bicarbonate at a temperature of about -10 to about 25 ° C while stirring the mixture formed for about 15 to about 120 minutes. The reaction mixture can then be washed with water to separate off inorganic salts and the solvent can be distilled off to obtain the desired product. This product can be used as such or further purified by recrystallization or other conventional means.
The compounds of the formula II can be prepared by reacting a substituted ^ aniline of the formula

10

NH,

(IV)

in which R ¹ and R ^{2 have} the meanings given above, with a compound of the general formula V

OCH ₃

HaI-CH ₂ -CH

OCH ₃

with a Dlol or Dlthlol of the general formula VII

20th

30th

35

Z ¹ -C H

/ I

Hal-CH ₂ -CH (CH ₂ ) ,, (V)

Z ² -C H

can be obtained in which Hai halogen, e.g. B. chlorine or bromine, and Z ¹ , Z ² and m have the meanings given above. This reaction is carried out by reacting a compound of the formula IV with a compound of the formula V in an inert organic solvent, e.g. B. dimethylformamide, In the presence of an acid acceptor, e.g. B. an alkali metal carbonate or bicarbonate with refluxing the resulting mixture for about 4 to about 48 hours. The reaction mixture can then be filtered off and distilled to obtain the desired product.

The compounds of the general formula V are obtained by reacting an acetal of the general formula Formula VI

45

50

55

60

H H

H — C— (CH ₂ ) _m —C ^{— H Z 1} HZ ² H

65

(VU) .

wherein Z ¹ , Z ² and m have the meanings given above. This reaction is carried out by reacting the compound of the formula VI with the compound of the formula VII in approximately equimolar amounts and in the presence of an acid catalyst, e.g. B. sulfuric acid or toluenesulfonic acid, under anhydrous conditions. The mixture can be refluxed for about 1 to 4 hours. The reaction mixture can then be distilled under reduced pressure to give the desired product.

Examples of substituted anilines of the formula IV are 2,6-dimethylaniline, 2,6-diethylaniline and 2,6-di-propylaniline and 2,6-dibutylaniline.

Examples of-haloalkanyl chlorides of the formula III are chloroacetyl chloride, bromoacetyl chloride and iodoacetyl chloride.

Examples of DIoJe and dithiols of the formula VII suitable for the preparation of the compounds of formula V are Ethandlthiol-1,2, Propanedithiol-1,3 and Butanedlthiol-1,4.

The preparation of the compounds according to the invention is explained in detail in the following examples.

example 1

N-a-chloroacetyl-N-iUS-dloxolan ^ -ylmethyD ^ .o-dimethylanilln

(a) The methyl acetal of 2-chloroacetaldehyde (125 g; 1.0 mol) and 1,2-ethanediol (62 g; 1.0 mol) are placed in a glass reaction flask equipped with a mechanical stirrer, thermometer and reflux condenser. 0.3 g of toluenesulfonic acid is added to the flask and the reaction mixture is refluxed for about 2 hours. The reaction mixture is then distilled under reduced pressure to remove methanol and the desired product, namely 2-chloromethyl-1,3-dioxolane, is obtained.

(b) 2,6-dimethyl-aniline (75 g), 2-chloromethyl-1,3-dioxolane (25 g), potassium carbonate (34 g) and dimethylformamide (50 ecm) were in one with a mechanical stirrer, thermometer and reflux cooler equipped glass flask. The reaction mixture was refluxed for about 18 hours. It was then filtered and distilled, the desired product, namely N- (1,3-Dioxolan-2-ylmethyl) -2,6-dlmethylanllln, received.

(c) N- (1,3-Dioxolan-2-ylmethyl) -2,6-dlmethylanllln (7.8 g), sodium bicarbonate (7.0 g), doxane (20 ecm) and Water (4 ecm) was poured into a glass flask equipped with a mechanical stirrer and thermometer given. The mixture was cooled to about 0 ° C. and then added with stirring for about 15% Minutes to 5.0 g of chloroacetyl chloride. After the addition had ended, stirring was continued for about 1 hour. Then gave 100 ecm of ether were added and the resulting solution was washed with water. The washed solution was then dried over anhydrous magnesium sulfate. After the solvents had evaporated, one remained

solid residue, which was encapsulated from ether / pentane, whereby the desired product, namely N-cc-chloroacetyl-N-O ^ -dioxolan ^ -ylmethyD ^ .ö-dlmethylanlilln with a melting point of 58 received up to 60 ° C.

Example 2

N-a-chloroacetyl-N-U ^ -dioxolan ^ -ylmethyD ^ ö-dläthylanllln

(a) 2,6-Diethylanilln (75 g; 0.5 mol), 2-chloromethyl-1,3-dloxolane (25 g; 0.2 mol), potassium carbonate (22 g; 0.2 Mol) and dimethylformamide (50 ecm) were put in one with a mechanical stirrer, thermometer glass flask equipped with a reflux condenser. The reaction mixture was stirred for about Heated for 18 hours. Then filtered and distilled, giving the desired product, viz N- (1,3-DIoxolan-2-ylmethyl) -2,6-dläthylanllln was obtained.

(b) N- (1,3-Dloxolan-2-ylmethyl) -2,6-dläthylanllln (7.7 g), sodium bicarbonate (6.0 g), dioxane (20 ecm) and Water (4 ecm) was poured into a glass flask equipped with a mechanical stirrer and thermometer given. This mixture was cooled to about 0 ° C. and added with stirring for about 15 minutes 4.0 g of chloroacetylchlorld. After the addition had ended, stirring was continued for about 1 hour. then the mixture was mixed with 100 ecm of ether and the resulting solution was washed with water. The washed one Solution was then dried over anhydrous magnesium sulfate and solvents became distilled off leaving a solid residue. This residue was recrystallized from ether / pentane, the desired product, namely N-α-chloroacetyl-N- (1,3-dioxolan-2-ylmethyl) -2,6-diethylanllln with a melting point of 86 to 87 ° C.

Example 3
Na-chloroacetyl-N- (1,3-dloxolan-2-ylmethyl) -2-methyl-5-chloroaniline

(a) 2-Methyl-5-chloroanllln (75g), 2-chloromethyl-1,3-dloxolan (25g), potassium carbonate (22g) and dimethylformamide (50 ecm) were placed in a reaction flask equipped with a mechanical stirrer, thermometer and reflux condenser. The mixture was heated with stirring for about 26 hours.

It was then filtered and distilled, the desired product N- (1,3-Dloxolan-2-ylmethyl) -2-methyl-5-chloranllin being obtained with a boiling point of 116 to 118 ° C at a pressure of 13.33 Pa.

(b) N-tl, 3-dloxolan-2-ylmethyl) -2-methyl-5-chloranIIIn (8 g), sodium bicarbonate (7 g), Dloxan (50 ecm) and Water (5 ecm) were in a glass equipped with a mechanical stirrer and thermometer

piston given. The mixture was cooled to about 0 "C and treated with 4.3 g of chloroacetyl chloride Stirring added for about 15 minutes. After the addition had ended, stirring was continued for about 1 hour. then 100 ecm of ether were added to the mixture and the resulting solution was washed with water. The washed one Solution was then dried over anhydrous magnesium sulfate and solvent was "under." A solid residue was distilled off. This residue was recrystallized from hexane, and the desired product was obtained, namely N-α-chloroacetyl-N-d ^ -dioxolan ^ -yhnethyO ^ -methyl-S-chloranilln with a melting point of 88 to 89 ° C.

Example 4
Na-chloroacetyl-N-tU-dlthiepan ^ -ylmethyO ^ o-dläthylanllln

(a) The diethyl acetal of 2-chloroacetaldehyde (125 g; 1.0 mol) and butandlthlol-1,4 (122 g; 1.0 mol) are in into a glass flask equipped with a mechanical stirrer, thermometer and reflux condenser. 0.3 g of toluenesulfonic acid is added to the reaction mixture and the mixture is kept for about 2 hours at reflux. Then the reaction mixture is distilled under reduced pressure and one obtains the desired 2-chloromethyl-1,3-dlthlepane.

(b) 2,6-Dläthylanllln (75 g), 2-chloromethyl-1,3-dithlepane (36.5 g), potassium carbonate (34 g) and dimethylformamide (75 ecm) are placed in one equipped with a mechanical stirrer, thermometer and reflux condenser Glass flask given. The reaction mixture is heated to reflux for about 18 hours. The mixture is then filtered and the desired product is distilled, namely N- (1,3-dithlepan-2-ylmethyl) -2,6-dläftylanllln.

(c) N- (1,3-Dlthlepan-2-ylmethyl) -2,6-dläthylan! lln (15 g), sodium bicarbonate (10 g), Dloxan (30 ecm) and Water (5 ecm) are poured into a glass flask equipped with a mechanical stirrer and thermometer given. The mixture is cooled to about 0 ° C. and 7 is added with stirring for about 15 minutes g Chloracetylchlorld too. After the addition has ended, the mixture is stirred for a further 1 hour. Then you move that Mix with 100 ecm of ether and wash the resulting solution with water. The washed solution becomes then dried over anhydrous magnesium sulfate and solvents leaving a solid Residue distilled off. The residue is recrystallized and gives the desired product, namely N-a-chloroacetyl-N-d ^ -dlthlepan ^ -ylmethyD ^ .ö-dläthylanilln.

Example 5
Na-chloroacetyl-NO.S-dloxan ^ -ylmethyD ^ o-diethylanilln

(a) The dimethyl acetal of 2-chloroacetaldehyde (125 g; 1.0 mole) and propanedol-1,3 (76 g; 1.0 mole) are In into a glass flask equipped with a mechanical stirrer, thermometer and reflux condenser. The reaction mixture is mixed with 0.3 g of toluenesulfonic acid and then held for about 3 hours Reflux. This is followed by distillation under reduced pressure and the desired product is obtained, namely 2-chloromethyl-1,3-dloxane.

(b) 2,6-diethylaniine (75 g), 2-chloromethyl-1,3-dioxane (14 g), potassium carbonate (34 g) and dimethylformamide (60 ecm) are placed in one equipped with a mechanical stirrer, thermometer and reflux condenser Glass flask given. The reaction mixture is refluxed for about 18 hours. Then filtered and distilled, whereby the desired product, namely N- (1,3-Dloxan-2-ylmethyl) -2,6-diethylanllln receives.

(c) N- (1,3-Dlthiepan-2-ylmethyl) -2,6-diethylaniIin (15 g), sodium bicarbonate (10 g), dioxane (30 ecm) and Water (5 ecm) is poured into a glass flask equipped with a mechanical stirrer and thermometer given. The mixture is cooled to about 0 ° C. and added with stirring for about 15 minutes 7 g of chloroacetyl chloride. After the addition has ended, the mixture is stirred for a further 1 hour. Then you move that Mix with 100 ecm of ether and wash the resulting solution with water. The washed solution becomes then dried over anhydrous magnesium sulfate and solvents leaving a solid Residue distilled off. The residue is recrystallized and gives the desired product, namely N-ar-chloroacetyl-N- (1,3-dithiepan-2-ylmethyl) -2,6-dläthylanllln.

Example 6

N-a-chloroacetyl-N-U.S-dioxepan ^ -ylmethyD- ^ o-diethylaniline

_w (a) The dimethyl acetal of 2-chloroacetaldehyde (125 g; 1.0 mol) and 1,4-butanedol (90 g; 1.0 mol) are placed in a reaction flask equipped with a mechanical stirrer, thermometer and reflux condenser. 0.3 g of toluenesulfonic acid is added to the reaction mixture and the mixture is then refluxed for about 3 hours. It is then distilled under reduced pressure and the desired product, namely 2-chloromethyl-1,3-dloxepane, is obtained.

(b) 2,6-diethylaniline (75 g), 2-chloromethyl-1,3-dioxepane (15 g), potassium carbonate (34 g) and dimethylformamide (60 ecm) are placed in one equipped with a mechanical stirrer, thermometer and reflux condenser Glass reaction flask given. The reaction mixture is refluxed for about 18 hours. then it is filtered and distilled, whereby the desired product, namely N- (1,3-dioxepan-2-ylmethyl) -2,6-diethylanllln receives.

60

(c) N- (1,3-Dloxepan-2-ylmethyl) -2,6-dläthylanllln (26.3 g), sodium carbonate (15 g), Dloxan (30 ecm) and Water (4 ecm) is placed in a reaction flask equipped with a mechanical stirrer and thermometer given. The mixture is cooled to about 0 ° C. and added with stirring for about 15 minutes with 15 g of Chloracetalchlorld. After the addition has ended, the mixture is stirred for about ' 1 hour. Then add 100 ecm of ether to the mixture and wash the resulting solution with it Water. The washed solution is then dried over anhydrous magnesium sulfate and solvent is distilled off leaving a solid residue. The residue is recrystallized, whereby one the desired product, namely N-a-chloroacetyl-N-iU-dloxepan ^ -ylmethyO ^ .ö-dläthylanilln receives. I.

ίο |

Further compounds falling within the scope of the invention can be prepared according to the above-mentioned Belspie- |

len processes described in detail can be obtained with appropriate starting materials.

The compounds according to the invention are generally used for practical use as herbicides incorporated into herbal compositions consisting of an inert carrier and a herbal toxic amount

'S such a connection exist. Such herbicidal compositions enable the active compound to be easily applied to the weed stones in any desired amount. These compositions can be solids, e.g. B. fine powders, granulates or wettable powders; they can also be liquid and in the form of solutions, aerosols or as emulsifiable concentrates.
Dust-like products are obtained, for example, by grinding and mixing the active compound with I

a solid inert carrier, e.g. B. talc, clay, silica, pyrophylllt. Granules are obtained by granular carriers, e.g. B. the attapulgites or the vermiculites, which usually have a particle size of about 0.3 to 1.5 mm, impregnated with the compound usually dissolved in a suitable solvent. Wettable Powders Which In Water Or Oil Up To Any Concentration Of The Active Compound Can be aerated can be obtained by incorporating wetting agents in concentrated dust-free compositions.

In some cases the active compounds are in common organic solvents, e.g. B. kerosene or Xylene, soluble to the extent that they can be used directly as solutions in these solvents. Solutions of herbicides can often be sprayed as aerosols under excess pressure. Preferred liquid However, compositions are emulsifiable concentrates made from an active compound of the invention and a solvent and an emulsifying agent as inert carriers. Such emulsifiable Concentrates can be mixed with water and / or oil at any concentration of the active compound stretched and sprayed onto the weed infestation site. The most common in these concentrates Emulsifiers used are non-ionic or mixtures of non-ionic with anionic surface-active agents Means. When using some emulsifying agent systems, a reverse Lmulston (water in oil) for direct application to weed-infested areas.

For example, a typical herbicidal composition according to the invention consists of 10 parts by weight the compound according to Example 1 and 90 weight points of talc powder, which in a mechanical grinding mixer mixed and ground to a homogeneous, free-flowing dust with the desired particle size will. This fine powder is suitable for direct application to the weed infestation site.

The compounds according to the invention can be applied as herbicides in any manner known to the person skilled in the art will. One method of controlling weed growth is by knowing the location of the Weeds contacted with a herbicide composition consisting of an inert carrier and one for this Weed species herbizld toxic amount of an active ingredient, namely a compound of the invention, consists. The concentration of the compounds according to the invention in the herbicidal compositions varies strongly with the nature of the composition and the intended use; Usually included however, the herbicidal compositions contain about 0.05 to 95% by weight of the active compounds of the invention. In a preferred embodiment of the invention, the herbicide compositions contain about 5 to about 75 percent by weight of the active compound. The compositions can also contain other Substances, e.g. B. Stabilizers, spreading agents, adhesives, tackifiers, fertilizers, contain.

Weeds are undesirable plants that grow unintentionally, have no economic value and interfere with the production of useful or ornamental plants or impair the well-being of livestock. The compounds according to the invention are particularly suitable for weed control, since they are toxic to many species and varieties of weeds, but are relatively non-toxic to many useful plants. The exact amount of compound required will depend on several factors including the resilience of the particular weed variety, the weather, the type of soil, the type of application, the type of crops in the same area, and the like. While the application of only about 6.9 mg or 14 mg of active compound per m ² can be sufficient for good control of a slight weed infestation that grows under unfavorable conditions, the application of 2.24 g / m ² or more of active compound can be required for good control of dense weed infestation of stubborn, perennial, growing under favorable conditions.

The herbicidal toxicity of the compounds according to the invention was demonstrated by tests in which several types of weeds were checked before the seeds emerged. In these experiments, small plastic flower pots filled with dry soil were sown with the weed seeds. 24 hours or less after sowing, the pots were sprayed with water until the soil was moistened, and the test compounds were sprayed onto the soil surface in the form of aqueous emulsions of acetone solutions containing emulsifying agents in the indicated concentrations.
After the spraying, the pots were brought into the greenhouse and, if necessary, additionally heated and

watered daily or more frequently. The plants were kept under these conditions for 25 to 35 days at which point in time the condition of the plants and the degree of their impairment on a range of 0 to 10 scale was measured as follows: 0 = no impairment, 1, 2 = slight impairment, 3, 4 = moderate impairment, 5, 6 = moderately severe impairment, 7, 8, 9 = severe impairment and 10 = dead. The data given in Table 1 show the herbicidal activity of the compounds according to Examples 1 and 2 against various weeds.

The effectiveness of the compounds according to the invention according to Examples 1 and 2 was compared with that of the known "alachlor" [2 ', 6'-Dläthyl-N- (methoxymethyl) -2-chloro-acetanilld], in each case with regard to the negative effects on a number of different crops. In Table II, the percentage of plants destroyed during the treatment, namely before the seeds emerge, is given as 0.224 g / m ^{2 of} the corresponding active substance, while in Table IH the percentage decrease in the status and growth of the plants when treated with the compound according to the invention and with the comparison compound is shown. The results show that the compounds according to the invention completely destroy the most common weed species (Table I), but at the same time impair the useful plants to a far lesser extent (Table II and III) than the comparative compound.

Table I. concentration Carex Sorghum Cheno- weed Echinochloa Digitaria 0.224 g / m ² halepense podium Setaria crus-galli sanquinalis Degree of impairment 10 10 9 10 lutescens 10 10 4th 10 9 10 10 10 10 link 2 10 10 10 9 9 10 1 10 S. 10 9 9 9 example 1 10 10 9 10 8th 10 10 4th 10 9 9 10 10 9 2 10 8th 9 9 9 9 1 10 8th 3 9 8th 9 Example 2 9

Table II

Percentage loss of plants when treated before seed emergence

Alachlor 0.224 g / m ²

Compound according to Example 1 0.224 g / m ²

alfalfa

carrot

cotton

cucumber

Sorohlm grain

Lespedeza

oats

Peanut

green bean

Southern Pea

Soybean

spinach

tomato

wheat

Beetroot

pumpkin

20 85 55 89 67 59 17 85 28 27 17 72 63 58 34 51

6 13 23 50 13 35 25 92 18 15 16 31 50

Table III

Percentage losses if treated before seed emergence

Alachlor (0.336 g / m ² Growth Was standing- reduction reduction 30th 30th 50 80 100 100 50 30th 0 80 60 50 50 0 90 90 80 40

Compound according to Example 2 (0.448 g / m ² )

Stand growth

Diminution diminution

Carrot ίο tomato lettuce broccoli cucumber ¹⁵ lentil pea wheat rye

0 0 0 0 0 30th 0 0 0 0 0 0 0 0 20th 20th 20th 0

Claims (1)

Patent claims: 1. α-Halo-acetanilides of the general formula I. Z ¹ -CH ₂ I. / ι ι CH ₂ -CH (CH ₂ ) ,, -NZ ² - CH ₂ 00 ίο \ = / \, C-CH ₂ -X ^m Il I ο I wherein R ¹ and R ² independently of one another each have an alkyl group with 1 to 4 carbon atoms, X is halogen, Z ¹ and Z ^J, independently of one another, are oxygen or sulfur and m is an integer from 0 to 2.