DE1443731C - Halogen-substituted benzodinitriles - Google Patents

Description

The invention relates to halogen-substituted benzodinitriles of the general formulas

CN

IO

Cl

CN

20th

in which R denotes a fluorine or chlorine atom.

As has been found, the compounds according to the invention are distinguished by excellent properties biological effectiveness and can therefore be used as fungicides, nematocides and herbicides.

A biological effectiveness of this kind was already found earlier in the case of halogen-substituted benzonitriles. So was z. B. Tetrafluoroterephthalic Acid Nitrile as an active ingredient of fungicidal, nematocidal and selectively acting herbicidal agents are proposed. It is also known to be herbicidal and insecticidal Effectiveness of polychlorinated benzonitriles, as well as that of substitution products terephthalic acid triple or quadruple chlorinated on the ring, which also has nematocidal activity (French patent specification 1 265 053).

The latter group of active ingredients, except for chlorophthalic acid esters also includes their N-substituted amides and esters of ring-chlorinated thiophthalic acid, However, in practical use, it was found to be many times the compounds according to the invention inferior, for which reference is made to the example part of the present description.

The benzonitriles according to the invention are prepared in a manner known per se and not claimed here from substituted phthalic or isophthalic acid chlorides which are initially only occupied by chlorine atoms at the ring sites bearing chlorine or fluorine atoms in the end product. One passes into the solution of the acid chloride in z. B. xylene, or dioxane at 40 to 60 ° C ammonia and then subjects the acid amide obtained to dehydration with phosphorus pentoxide or phosphorus oxychloride. If necessary, 2 or 3 chlorine atoms are then replaced by fluorine with halogen exchange on the acid nitrile chlorinated in the ring. B. potassium fluoride or copper fluoride in a solvent at elevated temperature (80 to 200 ⁰ C).

Another manufacturing option, also not claimed here for the halogenated phthalic acid dinitriles according to the invention is that one a corresponding hexahalogenbenzene with 2 moles of potassium or with cuprocyanide.

When using the Verbindüngen invention as pesticides utilizing ^fi 5 of their biological, in particular fungicidal activity, the active ingredient is usually mixed with one of the known solid or liquid carrier and is together with it as a solution, dispersion or dusting agent, that is in powder form, are used, The concentration of active ingredient depends primarily on the type of application and the intended effect and the carrier must be tailored to the physiological conditions. As a herbicide, the active ingredient is expediently used in a preparation in water and acetone; If necessary, a wetting agent can be added to liquid preparations in both cases, and the compounds can of course be used in admixture with any other compatible active ingredients. To combat nematodes, the active ingredient is either mixed in solid form (carrier, auxiliary substances) with the soil or introduced into the soil, or used as a liquid (solution, dispersion) for watering or sprinkling the soil. All of these application forms correspond to the methods customary in agriculture and horticulture, and their choice can be left to the person skilled in the art.

The example explains the preparation of the compounds according to the invention, while the comparative experiments demonstrate their superiority over known ones Show active ingredients. · ·.

The following active ingredients were used as claimed here:>

1. ^ S-Difluor-So-dichlorobenzodinitril (F. 134 to 135.5 ⁰ C),

2. 2,3,6-Trifluoro-5-chlorobenzodinitrile (F. 126.5 to 128 ⁰ Q,

3. 2,3,4,6-tetrachlorobenzodinitrile (temperature 250 to 251 ° C),

4. 2,4,6-Trifluoro-3-chlorobenzodinitrile (F. 109 bis
110 ⁰ C).

example

The halogenated benzodinitriles according to the invention are prepared from 2,3,4,6-tetrachlorobenzodinitrile from: For this purpose 2,3,4,6-tetrachloro-1,3-di- (hydroxymethyl) -benzene is first added treated with chlorine gas in carbon tetrachloride under UV light. The resulting acid chloride of 2,3,4,6-tetrachlorobenzene dicarboxylic acid (l, 3) is then reacted in dioxane with ammonium hydroxide to the diamide, which is converted into the corresponding dinitrile under the action of phosphorus oxychloride.

For this purpose, for example, 30 g (0.1 mol) 2,3,4,6-tetrachlorobenzenedicarboxylic acid (1,3) -diamide with 62 g (0.4 mol) phosphorus oxychloride heated vigorously for 3 hours, stirring at 75 to 110 ° C. After completion The vigorous evolution of HCl and cooling, the mixture is poured onto ice and the light brown The precipitate is filtered off, air-dried, washed three times with ether and finally at 110 ° C dried in the drying cabinet.

The 2,3,4,6-tetrachlorobenzodinitrile, which melts ^{at 250 to 251 °} C. after recrystallization from benzene, is obtained in good yield (over 90%).

Analysis: C ₈ Cl ₄ N ₂ .

Calculated ... C 36.1, H 0.0;
found .... C 36.2, H 0.2.

For the production of the fluorine-containing chlorobenzodinitriles if the 2,3,4,6-tetrachlorobenzodinitrile is used at KM) up to 120 "C in a solvent with potassium fluoride around, being this either your desired Fluorgehiill dosed accordingly or the reaction interrupted in good time. In the latter case

one obtains -a mixture of chlorine-fluoronitriles, which can be separated by fractional distillation.

• For example, 2,3,4,6-tetrachlorobenzodinitrile was converted into potassium fluoride at around 100 ° C by reacting with 6 Möl 2,4,6-trifluoro-3-chlorobenzodinitrile in dimethylformamide within 4 hours in a yield of almost 100% (M.p. 109 to 110 ° C).

Analysis: C ₈ ClF ₃ N ₂ .
Calculated ... C 44.3, H 0.0;
found .... C44.7, H0.2.

Finally, the 2,3,5,6-tetrachlorobenzodinitrile was made by the action of 3 moles of potassium fluoride at 110 to 115 ° C in dimethylformamide within A mixture of 2,5-difluoro-3,6-dichlorobenzodinitrile (melting point 134 to 135.5 ° C.) and 2,3,6-trifluoro-5-chlorobenzodinitrile for 3 hours (F. 126 to 128 ° C) obtained, which due to the different boiling points (278 to 279 ° C or 252 to 253 ° C) through fractionated Let distillation separate.

The analytical values showed that both products were practically pure.

Comparative examples

The superior action of the compounds according to the invention as crop protection agents gegen.den Compounds known from the aforementioned French patent specification 1,265,053 were established by means of comparative experiments proven.

Served as comparison substance:

A. Dimethyl 2,3,5-trichloroterephthalate,

B. 2,3,5,6-Tetrachloroterephthalic acid dimethylamide,

C. 2,3,5,6-Tetrachloroterephthalic acid tetraethylamide.

The dosage and the degree of suppression in percent are shown in Table I:

5 connection Table I. ' Degree of oppression Late bloom 6th dosage 1000 Early bloom ■, 2,3,4,6-tetrachloro in ppm 256 100 - ^I0 , benzonitrile 10 to 350 100 99 60 400 98 99 40 2000 92 • 94 30th 400 72 70 15th '20 2000 0 8th 10 0 2,4,6-trifluoro 5 3-chlorobenzo- 98 20th dinitrile 82 46 37 0 A; 0 Damage to plants 0 B. 9 C. 20th

30th

II. Efficacy against seed rot, etc. (pathogen: Pythium and Rhizoctonia species)

I. Effectiveness as a foliar protection fungicide

35

dosage kg / ha

Under-

degree of compression%

Sterilized soil in pots is doused with a preparation of the test compound in which the Fungicide concentration is 2000 ppm and the so

The attempts to protect tomato plants dosed is that in the open field about 721 on the hectare against leaf rot would determine the ability of the to hit. After watering, the compound to be investigated, the foliage of pots to be kept for a few days at 21 ° C, mat plants that are 12.7 to 17.8 cm high and 4 to 40. The compounds to be investigated are about 6 weeks old, against Infection with the pathogen - untreated soil evaluated for its effectiveness against fungus of the early bloom, Alternaria solani and the suppression of the mycelial growth of those of the late bloom, Phytophthora infestans, the fungus species to be met on the surface of the earth. For each fungal disease there was a double
Set of test plants with the test preparation in 45 “Table II

sprayed with different dosages. The experimental

preparation contained 187 cm ^{3 of} distilled water

0.2 g of the compound to be tested, 8 cm ^{3 of} acetone and compound

4 cm ³ emulsifier solution and was added in doses -

of 1000 and 200 ppm of the substance to be tested 5 °, ,,

used. m * 2,3,6-fluorine-5-chloro

After the sprayed substance dried benzodinitrile

was, the treated plants and control 2,5-difluoro-3,6-dichloro

plants (those with the same preparation, but benzodinitrile

has been sprayed without substance to be examined 55 2,4,6-trifluoro-3-chloro

were) sprayed with a spore suspension, each benzodinitrile

Cubic centimeters about 20,000 conidia of A. so- p ^

lani or 150,000 sporangia of P. infestans contained "

and 24 hours in one saturated with water vapor

The atmosphere was maintained, whereupon it was placed in the greenhouse with 60 efficacy against bean rust

were brought. . . ·

2 days after the start of the experiment with the early flowering bean test (three per pot) are used as test plants and 3 days afterwards for the late flowering test, where from the leaf angle of the cotyledons on the top three adult leaves, the three-part foliage leaves are counted as the infestation sites. The values obtained ⁶ 5 begin to develop, which were tested with a test / preparation for percentage suppression of the erosion with 20 (K) ppm fungicide. The disease was converted and / was based on the calculation, 71.8 or 14.1.5 kg of preparation per bt: i the K0ntrnllptlan7.cn / u observed infestation. Acres in the open '. With ^ prechon

71.8
71.8

71.8
143.5
143.5

100 100

100

44

5
Table III Degree of oppression connection dosage
kg / ha 92%, plants
something wither away
mert, chlorosis
no effect
no effect
no effect 2,4,6-trifluoro
3-chlorine
benzonitrile
A. 71.8
143.5
143.5
143.5 B. C.

IV. Effectiveness as bactericidal

The effectiveness of the compounds to be tested in various concentrations was compared examined the following four types of bacteria:

Erwinia amylovora (E. a.),
Xanthomonas phaseoli (X. p.), Micrococcus pyrogenes var. Aureus (M. a.), Escherechia coli (E. α).

The test was carried out on cultures of the bacterium in question, which the test compound in the below indicated concentration was added. The ability of the cultures to multiply in sterile meat broth and from this the degree of suppression compared to control cultures is determined. The results are listed in Table IV. .

Table IV

from three broad leaf types (buckwheat, asters and beets) and another from three types of grass (millet, perennial ryegrass, sorghum). The seeds were sown in aluminum trays and covered with 1/4 inch soil and watered. After 24 hours, a preparation of 125 mg of the compound to be tested in 20 cm ^{3 of} acetone and 20 cm ^{3 of} water and 2 drops of emulsifier solution was sprayed onto the earth. A dose of 40 cm ^{3 of} this preparation each

ίο corresponds to 27 kg of active substance per hectare in the shell Outdoors.

2 weeks after the treatment, the degree of suppression of the germ growth and thus the Effectiveness as a pre-emergence herbicide determined on the basis of the "fresh weight of the seedling. It resulted the following values:

connection

2,3,6-Trifluoro-5-chlorobenzodinitrile ...

2,5-difluoro-3,6-dichlorobenzodinitrile

2,4,6-trifluoro-3-chlorobenzodinitrile

concentration
"ρρϊή

250
100

250
100

250
100
250
250
500

Degree of suppression in% Ea. X. p. M. a. E. c.

100 100

100 100

100 100

0 16

100 38

100 100

100 100

0 21

100 11

10 0

100 100

13 8

20th

Table V dosage
'kg / ha Oppressive
Broad leaf
plant degree of efficiency
Oras
plants 20th
connection 27 60 0 ²⁵ 2,3,6-trifluoro-5-chloro
benzodinitrile .... r- 27
36
36
• 72 20th
15th
0
0 70 Vk 2
0
0
0 2,5-difluoro-3,6-di-
chlorobenzonitrile B. C.

V. Effectiveness as Pre-Emergence Herbicides

The effect of the compounds on the germination of the seeds and the growth of the germs in the soil was on tried two seed mixtures on one

Vk = stunted (1 = easy to 9 = difficult).

Tables I to V show that the compounds according to the invention in their biological Effectiveness in a wide variety of areas are superior to the known comparison substances.

Claims (1)

Claim: Halogen-substituted benzodinitriles of the general formulas F 'Y ^N R CV Y ^N CN CN R in which R denotes a fluorine or chlorine atom.