GB2066238A - Fungicidal 3-(3-(3-fluorophenyl)-2- triazenyl)-benzonitrile - Google Patents

Abstract

3-(3-(3-fluorophenyl)-2-triazenyl)- benzonitrile is prepared by coupling the diazonium salt of 3-fluoroaniline or 3- amino-benzonitrile with, respectively, 3-aminobenzonitrile or 3-fluoroaniline. It is an effective fungicide and plant growth regulant.

Description

SPECIFICATION Method for making and use as a fungicide 3-(3-(34luorophenyl).2-triazenyl)-benzonitrile This invention relates to the novel compound, 3-(3-(3-fluorophenyl)-2-triazenyl)-benzontrile which has the formula

a method for its preparation, to fungicidal and plant growth regulating compositions containing it and to a method of controlling fungi with it.

The compound may be prepared by coupling the diazonium salt of either 3-fluoroaniline or 3-aminobenzonitrile with an equivalent quantity of 3-amino-benzonitrile or 3-fluoroaniline respectively. The reaction proceeds at low temperature and the reaction is advantageously effected by bringing together aqueous solutions of the reactants in the presence of an alkaline medium. The resulting triazene is insoluble in the reaction medium and may be separated therefrom with ease. The following example more fully demonstrates the preparation.

Example 1 To a stirred suspension of 3-aminobenzonitrile (11.8 g, 0.10 mole) in water (50 ml), ice (33 g) was added concentrated hydrochloric acid (17.33 ml). The mixture was cooled and maintained below 5"C during the addition, over 25 minutes, of a solution of sodium nitrite (7.2 g) in water (20 ml). To this mixture at T < 5 C was added a solution of 3-fluoroaniline (11. 1 g, 0.10 mole) in water (50 ml), ice (33 g) and concentrated hydrochloric acid (8.67 ml). Sodium acetate (17 g) in water (60 ml) was added and the slurry stirred and allowed to warm to ambient temperature over a period of 4 hours. The resulting solid was filtered, washed with water and dried in vacuo 22.7 g, 99%, m.p. 140"-142"C.

C13H > FN4 Found: C,64.90; H,3.67; N,23.47; F,7.68.

Req: C,64.99; H,3.78; N,23.32; F,7.91 The compound, according to the invention, can be used against parasitic fungi, especially those fungal organisms ordinarily found on the above ground portions of plants. The compound can be applied to protect seeds and also can be distributed in the soil at fungicidal concentrations. Accordingly the invention includes within its scope a method for the control of fungal organisms, particularly Ascomycetes and Oomycetes and Fungi Imperfecti attacking plants or plant parts which method comprises applying the composition of the invention to the plants, the plant parts or to the organisms or to their habitats. The following may be mentioned as important fungi to be combated with the compound of the invention: Plasmopara viticola and Podosphaera leucotricha.

It is an advantage of the present invention that compositions containing this compound can be applied to growing vegetation to give a residual and extended control of fungi over a period of several months with a single application. Further, the compound has been found to be translocated in plants and thus it is an advantage of the present invention that the compound can provide a systemic protection against the plant attacking organism. When used in higher concentrations the compound could also be used as a plant growth regulator.

The method of the present invention comprises contacting a fungal organism with a fungicidal amount of the compound. However, the present invention also embraces the employment of a liquid, powder or dust composition containing the compound and one or more additives including organic solvents, petroleum distillates, water or other liquid carriers, surface active dispersing agents, and finely divided inert solids. In such compositions, the compound oftentimes is present in a concentration from 2 to 98 percent by weight or when the carrier is a surface active agent, from 0.1 to 20 percent by weight.Depending upon the concentration in the composition of the compound, such augmented compositions are adapted to be employed for the control of the undesirable fungi or employed as concentrates and subsequently diluted with additional inert carrier to produce the ultimate treating compositions. In general, however, good results can be obtained with liquid compositions containing from 0.0001 to 2.0 percent by weight of the toxicant. With dusts, good results can usually be obtained with compositions containing from 0.001 to 2.0 percent or more by weight of toxicant. Where the compositions are to be applied to living plants, it is preferred that the toxicant be present in an amount not to exceed 0.8 percent in liquid compositions and 1.0 percent in dusts.In terms of acreage application, good controls of fungal organisms can be obtained when the compounds are applied to plots of growing plants at a dosage of from 0.004 to 3 or more pounds per acre (0.0045 to 3.36 kg/hectare). The excellence of the activity of this new compound is illustrated, without limitation, by the following examples where solutions or suspensions of the test chemical were prepared in aqueous isopropanol containing a small amount of a suitable wetter.

Example 2 Grape downy mildew/protectant.

The underside of the leaves of grape seedlings (cv. Carignane) at the 3-4 leaf stage were sprayed to run off with an aqueous suspension of the test material. After application the underside of the plant leaves were sprayed with a spore suspension in distilled water of Plasmopara viticola and the inoculated plants stored in an infection chamber at 165"C-185"C and 100% r.h. for 3 days. The plants were then transferred to the glasshouse for 3 days and finally returned to the infection chamber to induce sporulation. When the disease symptoms were well developed (12 weeks from spraying) the seedlings were graded for disease control by rating untreated seedlings as 'no control' and those with the absence of disease symptoms as '100% control'.

Grape downy mildewidelayed inoculation (protectant).

The test procedure was that used for the protectant test but the plants were inoculated 3-4 days after the application of the test chemical.

Grape downy mildew/repeated inoculation (protectant).

The test procedure of the delayed inoculation was followed but the grape seedlings were further inoculated with the disease 7 days after the first inoculation.

Grape downy mildew/treatment under moist conditions.

The delayed inoculation protectant test procedure was adopted but each night prior to inoculation the plants were placed in a biochamberat 100% r.h.

Grape downy mildew/translocation.

The protectant test procedure was utilised. Prior to spraying, however, the existing leaves of the plant were marked e.g., by punching holes, and the plant only inoculated 3-5 days after the growth of 2-3 new leaves. Assessment was made on the disease control on this new foliage only.

The concentration of the use and results can be seen from the following table.

TABLE I Grape Downy Mildew Tests Control in % over an active compound concentration range of: Test Procedure 0.12% 0.3% 0.01% 0.0075% Protectant 95 Delayed inoculation 99 99 25 Repeat inoculation 97 Moist conditions 100 97 90 Translocation 95 60 25 Example 3 Apple powdery mildew/root drench and foliar.

Apple seedlings (cv Red Delicious) at the 4-6 leaf stage were sprayed to run off with a 0.05% solution or suspension of the test chemical. The vermiculate in which the plant was growing was drenched with a similar solution at 0.0025% concentration. The plants were held in a greenhouse for 48 hours at 200-220C and then inoculated with an aqueous suspension of freshly harvested conidia of Podosphaera leucotricha (106 propagules/ml). The plants were graded after 7-12 days when inoculated, but untreated, plants sporulated profusely. The assessments were expressed as a percent control where inoculated, but untreated, plants were rated as 'no control' and the absence of disease symptoms as '100% control'.

At a concentration of 0.05% the compound of the invention gave a 90% control of the organism.

Claims (8)

1. 3-(3-(3-Fluorophenyl)-2-triazenyi)-benzonitrile.

2. A method for making 3-(3-(3-fluorophenyl)-2-triazenyl)-benzonitrile which comprises reacting the diazonium salt of 3-aminobenzonitrile with 3-fluoroaniline in aqueous suspension at a temperature below 5"C.

3. A composition comprising a carrier and a fungicidally effective amount of 3-(3-(3-fluorophenyl)-2 triazenyl)-benzonitrile.

4. A method forcontrolling fungi which comprises contacting a fungal organism or a substrate on which growth of a fungal organism is to be prevented with a fungicidally effective amount of 3-(3-(3-fluorophenyl) 2-triazenyl)-benzonitrile.

5. A method for preparing 3-(3-(3-fluorophenyl)-2-triazenyl)-benzonitrile substantially as hereinbefore described in Example 1.

6. A method for controlling fungi as claimed in claim 4 substantially as described in Example 2 or Example 3.

7. 3-(3-(3-fluorophenyl)-2-triazenyl-benzonitrile prepared by a method as claimed in claim 4 or claim 5.

8. 3-(3-(3-fluorophenyl)-2-triazenyl-benzonitrile substantially as described in Example 1.