N-Tetrachlorofluoroethylthio-Halo-Benzoyl Anilides and Their Use as Fungicides

This invention relates to certain novel N-tetrachlorofluoroethyl-thio-halo-benzoyl anilides which are useful as fungicides.

The compounds of the present invention correspond to the formula ##STR2## in which R is chlorine, bromine, iodine or trifluoromethyl, preferably in the ortho position, and R.sup.1 is hydrogen, chlorine, bromine, iodine, trifluoromethyl, alkyl having 1 to 5 carbon atoms, alkoxy having 1 to 2 carbon atoms or alkylthio having 1 to 2 carbon atoms.

Although the compounds of the invention are generally active as fungicides, it has been discovered that they are also effective as systemic toxicants and this ancillary feature greatly increases their usefulness and versatility in treating fungus infected food crops. As those skilled in the art are aware, a systemic biocide is taken up internally by the organism to which it is applied and lodges in the tissues while still retaining toxicological properties. When used to protect food crops systemic toxicants are not subject to weathering since they are confined within the interstices of the plant tissues which are thereby internally immunized against the attack of harmful fungi, blights and similar pesticidal microorganisms.

The compounds of the present invention are prepared by the following general reaction. ##STR3##

Generally, a mole amount of the substituted benzoyl chloride reactant, dissolved in benzene, is added to a mixture of the aniline reactant and a slight mole excess of an HCl acceptor such as triethyl amine. The mixture is refluxed for 1/2 hour and then cooled. The solid reaction product is diluted with a solvent such as ethyl acetate or chloroform and washed with water twice and salt solution once. The final product is dried over MgSO.sub.4, filtered and evaporated. ##STR4##

Under a dry nitrogen atmosphere a mole amount of the reaction product from Reaction No. 1 is dissolved in dry THF. Next, a slight mole excess of NaH is added with stirring. The mixture is refluxed for 1 hour and cooled. ##STR5##

A mole amount of ClSCCl.sub.2 CCl.sub.2 F in THF is added dropwise to the reaction mixture of Reaction No. 2. The mixture is refluxed for 21/2 hours and large amount of CH.sub.2 Cl.sub.2 is added to the solid reaction product.

The product is washed twice with water, dried over MgSO.sub.4 and evaporated.

Preparation of compounds of this invention is illustrated by the following example.

43.2 g (0.464 moles) aniline and 46.9 g. triethylamine are mixed in 930 ml benzene by stirring. A solution of 123.7 g. (0.464 moles) 2-iodobenzoyl chloride in 450 ml benzene is added to the first mixture through a dropping funnel. An exothermic reaction takes place. After the addition is finished, the mixture is refluxed for 1/2 hour. The mixture is cooled with the product solidifying. The product is filtered, added to water, and stirred to dissolve triethylaminehydrochloride. The product is filtered again and dried to yield 146.8 g. of the desired product. (98% yield) m.p. 141.degree.-4.degree. C.

8.075 g. (0.025 moles) of the amide reaction product of Example I is dissolved in 60 ml of dry THF under a dry nitrogen atmosphere. 0.66 g (0.0275 moles)NaH is added to the mixture with stirring. The mixture is refluxed for 1 hour and then cooled.

(0.025 moles) of ClSCCl.sub.2 CCl.sub.2 F dissolved in 12 ml THF is added dropwise to the cooled reaction mixture of Example II. The mixture is then refluxed for 21/2 hours. Next 150 ml CH.sub.2 Cl.sub.2 is added, the mixture washed twice with water, dried over MgSO.sub.4 and evaporated to yield the desired product.

The following is a table of certain selected compounds that are preparable according to the procedure described hereto. Compound numbers are assigned to each compound and are used through the remainder of the application.

A. Evaluation for Preventative Action

1. Bean Rust Test

A candidate chemical is dissolved in an appropriate solvent and diluted with water containing several drops of Tween 20.sup.R, a polyoxy-ethylene sorbitan monolaurate wetting agent. Test concentrations, ranging from 1000 ppm downward, are sprayed to runoff on the primary leaves of pinto beans (Phaseolus vulgaris L.). After the leaves are dried, they are incoulated with a water suspension of spores of the bean rust fungus (Uromyces phaseoli Arthur) and the plants are placed in an environment of 100% humidity for 24 hours. The plants are then removed from the humidity chamber and held until disease pustules appear on the leaves. Effectiveness is recorded as the lowest concentration, in ppm which will provide 50% reduction in pustule formation as compared to untreated, inoculated plants. These values are recorded in Table II.

2. Bean Powdery Mildew Test

A candidate chemical is prepared and applied in the same manner as for the bean rust test. After the plants are dry, the leaves are dusted with spores of the powdery mildew fungus (Erysiphe polygoni De Candolle) and the plants are retained in the greenhouse until the fungal growth appears on the leaf surface. Effectiveness is recorded as the lowest concentration, in ppm, which will provide 50% reduction in mycelial formation as compared to untreated, inoculated plants. These values are recorded in Table II.

3. Tomato Early Blight

A candidate chemical is prepared and applied in the same manner as the bean rust test except that 4-week old tomato (Lycopersicon esculentum) plants are utilized as the host plant. When the leaves are dry, they are inoculated with a water suspension of spores of the early blight fungus (Alternaria solani Ellis and Martin) and placed in an environment of 100% humidity for 48 hours. The plants are then removed from the humidity chamber and held until disease lesions appear on the leaves. Effectiveness is recorded as the lowest concentration, in ppm, which will provide 50% reduction in number of lesions formed as compared to untreated, inoculated plants. These values are recorded in Table II.

4. Blue Grass Leaf Spot

A candidate chemical is prepared and applied in the same manner as the bean rust test except that 4-week old Kentucky Bluegrass (Poa pratensis) plants are utilized as the host plant. When the leaves are dry, they are inoculated with a water suspension of spores of the blue grass leaf spot fungus (Helminthosporium sativum) and placed in an environment of 100% humidity for 48 hours. The plants are then removed from the humidity chamber and held until disease lesions appear on the leaves. Effectiveness is recorded as the lowest concentration, in ppm, which will provide 50% reduction in number of lesions formed as compared to untreated, inoculated plants. These values are recorded in Table II.

1. Bean Rust Test

Untreated bean plants (Phaseolus vulgaris L.) are inoculated with spores of the bean rust fungus (Uromyces phaseoli Arthur) and placed in an environment with 100% humidity for 24 hours. The plants are then removed from the humidity chamber and held in the greenhouse for 2 days to allow the disease to become established. A candidate chemical is then prepared and applied in the same manner as in the bean rust test in Evaluation for preventative action. Eradicative effectiveness is recorded as the lowest concentration, in ppm, which will provide a 50% reduction in number of pustules appearing the leaves as compared to untreated inoculated plants. These values are recorded in Table II.

2. Bean Powdery Mildew Test

Untreated pinto bean plants are dusted with spores of the powdery mildew fungus (Erysiphe polygoni De Candolle) and maintained in the greenhouse until mycelial growth appears in the leaf surface. A candidate chemical is then prepared and applied in the same manner as for the bean rust test. Four days later the leaves are examined for inhibition of further mycelial growth. Eradicative effectiveness is recorded as the lowest concentration, in ppm, which will provide a 50% inhibition of viable, sporulating mycelium as compared to untreated inoculated plants. These values are recorded in Table II.

The compounds of this invention are generally embodied into a form suitable for convenient application. For example, the compounds can be embodied into pesticidal compositions which are provided in the form of emulsions, suspensions, solutions, dusts and aerosol sprays. In general, such compositions will contain, in addition to the active compound, the adjuvants which are found normally in pesticide preparations. In these compositions, the active compounds of this invention can be employed as the sole pesticide component or they can be used in admixture with other compounds having similar utility. The pesticide compositions of this invention can contain, as adjuvants, organic solvents, such as sesame oil, xylene range solvents, heavy petroleum, etc.; water; emulsifying agents; surface active agents; talc; pyrophyllite; diatomite; gypsum; clays, propellants, such as dichlorodifluoromethane, etc. If desired, however, the active compounds can be applied directly to feedstuffs, seeds, etc. upon which the pests feed. When applied in such a manner, it will be advantageous to use a compound which is not volatile. In connection with the activity of the presently disclosed pesticidal compounds, it should be fully understood that it is not necessary that they be active as such. The purposes of this invention will be fully served if the compound is rendered active by external influences, such as light or by some physiological action which occurs when the compound is ingested into the body of the pest.

The precise manner in which the pesticidal compositions of this invention are used in any particular instance will be readily apparent to a person skilled in the art. Generally, the active pesticide compound will be embodied in the form of a liquid composition; for example, an emulsion, suspension, or aerosol spray. While the concentration of the active pesticide in the present compositions can vary within rather wide limits, ordinarily the pesticide compound will comprise not more than about 15.0% by weight of the composition. Preferably, however, the pesticide compositions of this invention will be in the form of solutions or suspensions containing about 0.1 to 1.0% by weight of the active pesticide compound.