DE1668899B1 - 2-methyl-5,6-dihydropyran-3-carboxylic acid anilide and crop protection agents containing this - Google Patents

Description

The invention relates to 2-methyl-5,6-dihydropyran-3-carboxylic acid anilide the formula

( YC-NH
Lj-CH ₃

and pesticides containing them.

It is known that compounds of a similar constitution such as 2,3-dihydro-5-carboxanilido-6-methyl-1,4-oxathiin (II) and 2,3-dihydro-5-carboxanilido-6 - methyl - 1,4 - oxathiin - 4 - dioxide (III) fungicidal Have an effect on plants (see US Pat. No. 3,249,499 and Belgian Patent Specification 679 984, pp. 19 and 29).

(Π)

NH

/ X

(ΠΙ)

(III) 2,3 - dihydro - 5 - carboxanilido - 6 - methyll, 4-oxathiin-4-dioxide (known from Belgian patent 679 984).
Wheat was grown in pots and treated in the 3-leaf stage with the compound (I) in the use concentrations of 7.5, 15, 30, 60 and 120 mg active ingredient / 1 spray liquor. Each experiment was carried out four times, ie in four pots each, in each of which there were 10 wheat plants. An untreated control and wheat which had been treated with the compounds (II) and (III) at the same application rates were used for comparison. 1 day after the active substance coating had dried on, the plants were infected with a spore suspension of wheat yellow rust and placed in a moist chamber for 12 hours. Then the plants came into the greenhouse. 4 weeks after infection, the plants were assessed for disease infestation. The figures in Table 1 below indicate, for the respective application concentration, what percentage of the plants were affected by rust.

Table 1

Prophylactic treatment of winter wheat

against wheat yellow rust 1 day before infection.
Assessment of the effect 4 weeks after infection

C-NH

The known compound (II) has good prophylactic but only moderate systemic effects with leaf treatment and no effect with seed treatment. The known compound (III) possesses although good systematic effect and dressing effect when treating the seeds, the prophylactic effect, however, is very poor.

It has been found that 2-methyl-5,6-dihydropyran-3-carboxylic acid anilide is an effective fungicide and selective herbicide for plant crops. Compared to the known compound (II) is the new connection with regard to the systemic effect and the pickling effect and against the known compound (III) surprisingly superior in terms of prophylactic effect.

The particular advantage of 2-methyl-5,6-dihydropyran-3-carboxylic acid anilide lies in the fact that it combines the fungicidal properties of the known compounds (II), (III). That means that for Prevention of fungal attack, e.g. B. on cereals, no longer as before, initially the one known Compound and at a later stage of growth the other compound is applied must be, but that now the treatment with the new compound (I) alone by optional Dressing or application at an early stage of growth is sufficient to prepare the cultures To protect fungal infestation. In the following comparative tests, the effect of the compounds checked.

Tested substances:

(I) 2 - methyl - 5,6 - dihydropyran - 3 - carboxylic acid

anilide,
(II) 2,3-dihydro-5-carboxanilido-6-methyl-1,4-oxa-

Active ingredient 35 y % Yellow rust infestation upon application
concentration
mg active ingredient / 1 spray liquid 60 30th 15th 7.5 II 120 0 0 5 10 III 0 0 0 10 15th Untreated 0 35 60 100 100 15th 100 100 100 100 100

thiin (known
3 249 499),

from the USA patent

As can be seen from Table 1, the compound (I) has the same good effect as that Compound (II), but is significantly better than compound (III). The plants stayed up to one Active ingredient concentration of 30 mg / 1 completely free from infestation. Thereafter, the prophylactic treatment is the Plant 1 day before infection of the active ingredient (I) according to the invention of the known compound (III) in surprisingly superior.

Systemic effect

The systemic effect is equivalent to an internal therapeutic effect after ingestion the active substance, either through the leaves or through the seeds during dressing. After the crop plants treated in this way, in particular the grain, emerge, the active ingredient becomes transported to other, initially untreated parts of the plant, thereby protecting them from fungal infection to be protected.

Wheat seeds were treated with the active ingredient (I) in the application rates of 250, 125 and 60 g active ingredient / 100 kg of seeds dressed for 10 minutes. For comparison, seeds were used with the known compounds (II), (III) treated in the same application rates and in the same way.

The seeds treated in this way were sown 14 days later. After the seeds emerged

the plants are artificially infected in the 3 to 4 leaf stage with spores of brown rust of wheat. 4 weeks After infection, the treated plants and the untreated controls were checked for rust examined. The result obtained is summarized in Table 2 below.

Table 2
Seed treatment: dressing winter wheat

% Brown rust infestation 250 125 Pickling with 60 Active ingredient g active ingredient / 100 kg 0 0 Seeds 18th 100 100 100 I. 0 5 15th II 100 100 100 III Untreated

20th

The values found show that the active ingredient (I) in the application rates of 250 and 125 g Active ingredient / 100 kg seed gave full protection against infection by brown rust. It was similar too the known compound (III) is effective. On the other hand, the known compound (II) showed in the above Application rates no effectiveness. It follows that the active ingredient (I) as a seed dressing known compound (II) is surprisingly superior.

Wheat was grown in pots and four samples of wheat were used at the 2-leaf stage treated the active ingredient (I) in concentrations of 250, 125, 60, 30 and 15 mg active ingredient / 1 spray mixture. For comparison, the known compounds (II), (III) were used in the same way. More plants remained as an untreated control.

7 days after spraying with the spray mixture, the treated leaves were carefully cut off. To 5 weeks were the newly grown leaves that had not come into contact with the active ingredient were infected with a spore suspension of brown rust of wheat and placed in a humid chamber. Twelve hours later, the plants came into the greenhouse. 3 weeks after infection, the Checked disease infestation. The result is summarized in Table 3 below.

Table 3
Winter wheat - brown rust of wheat

Active ingredient % Br.
π
250 iunrostb
con
ig real
125 case at
centration
> toff / l Sp
60 Applic
nen
ritz broth
30th anxious
15th I. 0
15th 0
35 5
100 15th
100 30th
100 II 0 3 10 15th 25th Ill 100 100 100 100 100 Untreated ...

50

55

60

The values found show that the active ingredient (I) has a good systemic action against the infection has, to the same extent, the well-known

65 bond (III). In contrast, the known compound (II) shows only a very weak systemic effect. It turns out that the active ingredient (I) is surprisingly superior to the known compound (II) is.

The 2 - methyl - 5,6 - dihydropyran - 3 - carboxylic acid anilide is prepared by in itself known manner to either 2-methyl-5,6-dihydropyran-3-carboxylic acid with a chlorinating agent Reacts 2 - methyl - 5,6 - dihydropyran - 3 - carboxylic acid chloride and this with aniline in the presence of a inorganic or tertiary organic base, or that 2 - methyl - 5,6 - dihydropyran-3-carboxylic acid is reacted Reacts with phenyl isocyanate at elevated temperature.

Suitable chlorinating agents are preferably thionyl chloride or phosphorus pentachloride, phosphorus trichloride and phosphorus oxychloride. The chlorination is carried out at temperatures between -20 and +100 ⁰ C; it is preferred to work between 0 and 30 ° C., in particular when using thionyl chloride.

The chlorination is expediently carried out in an inert solvent, such as carbon tetrachloride, Chloroform, methylene chloride, toluene or benzene.

The reaction of the acid chloride with aniline is then in the presence of an inorganic or tertiary organic base carried out.

The reaction of 2-methyl-5,6-dihydropyran-3-carboxylic acid with phenyl isocyanate takes place at temperatures between 80 and 180 ° C., preferably between 140 and 170 ° C. After the reaction has ended it is appropriate to wash the reaction product with an inert solvent such as carbon tetrachloride or gasoline to remove excess phenyl isocyanate.

The 2 - methyl - 5,6 - dihydropyran - 3 - carboxylic acid anilide is an active ingredient in pesticides can be used in addition to customary inert carriers, especially as a fungicide and as a selective herbicide in plant crops. It is particularly effective against rust and smut fungi on cereals, e.g. B. against Wheat yellow rust and wheat brown rust, drift fire, stone fire and soil fungi such as Rhizoctonia. as Fungicide can be used both in crop protection and in stored product protection. As a herbicide it is particularly effective against field weeds.

The 2-methyl-5,6-dihydropyran-3-carboxylic acid anilide can be used in the customary manner with solid or liquid inert carriers, with adhesives, wetting agents, dispersants and grinding aids as a wettable powder, emulsion, suspension, dust or granulate. It can be mixed with other pesticides with which it forms compatible mixtures. Mineral materials, such as aluminum silicates, onerden ^T, kaolin, chalks, siliceous chalks, talc, kieselguhr, or hydrated silicic acid, or preparations are used as carriers may be used of these mineral substances with special additives, for example. B. Chalk with sodium stearate, greased. All common and suitable organic solvents, for example toluene, xylene, diacetone alcohol, cyclohexanone, isophorone, gasoline, paraffin oils, dioxane, dimethylformamide, dimethyl sulfoxide, ethyl acetate, butyl acetate, tetrahydrofuran, chlorobenzene and others can be used as carriers for liquid preparations.

Glue-like cellulose products or polyvinyl alcohols can be used as adhesives.

As wetting agents, all suitable emulsifiers such as oxyethylated alkylphenols, salts of aryl or Alkylarylsulfonic acids, salts of methyltaurine, salts of phenylkogasinsulfonic acids or soaps are used will.

Cell pitch (salts of lignosulphonic acid), salts of naphthalenesulphonic acid can be used as dispersants and, under certain circumstances, hydrated silicas or even kieselguhr can be used.

Suitable inorganic or organic salts, such as sodium sulfate, ammonium sulfate, Sodium carbonate, sodium bicarbonate, sodium thiosulfate, sodium stearate or sodium acetate, be used.

example 1

14.2 g of 2-methyl-5,6-dihydropyran-3-carboxylic acid are dissolved in 70 ml of absolute benzene, and 8.5 ml of thionyl chloride are added at 22 ° C. After standing for 2.5 hours, the mixture is concentrated to a quarter of its original volume under reduced pressure. The crude acid chloride obtained is then added dropwise over the course of 40 minutes to a stirred solution of 9.3 g of aniline and 9.5 g of pyridine in 100 ml of benzene, which is kept at -5.degree. The reaction mixture is then stirred for 1 hour without further cooling and then poured onto ice. The benzene solution is separated off, washed with water and dried over sodium sulfate. The benzene is then distilled off, 2-methyl-5,6-dihydropyran-3-carboxylic acid anilide being obtained in a yield of 16.3 g (75% of theory). After recrystallization from methanol / water (3: 1) with the addition of animal charcoal, the compound melts at 108 to 109 ^° C.

The infrared spectrum of the new compound shows characteristic IR bands at 3.05, 6.08 and 6.13 μ.

Example 2

14.2 g of 2-methyl-5,6-dihydropyran-3-carboxylic acid and 11.9 g of phenyl isocyanate (0.1 mol each) are heated ^{to 160 ° C. for 45 minutes.} After the reaction mixture has cooled, the crystal cake is washed with benzine to remove unreacted phenyl isocyanate and the residue is recrystallized from alcohol / water (3: 1). The 2-methyl-5,6-dihydropyran-3-carboxylic acid anilide is obtained in a yield of 17.6 g (81% of theory) with a melting point of 108 to 109 ^° C.

Claims (2)

Patent claims: 1.2-methyl-5,6-dihydropyran-3-carboxylic acid anilide. 2. Plant protection agents, characterized by a content of 2 - methyl - 5,6 - dihydropyran-3-carboxylic acid anilide in addition to the usual inert carriers.