SUBSTITUTED OXADIAZOLES FOR COMBATING PHYTOPATHOGENIC FUNGI

Abstract

The present invention relates to novel trifluoromethyloxadiazoles of the formula I or an N-oxide and/or their agriculturally useful salts and to their use for controlling phytopathogenic fungi, or to a method for combating phytopathogenic harmful fungi, which process comprises treating the fungi or the materials, plants, the soil or seeds to be protected against fungal attack, with an effective amount of at least one compound of the formula I, or an N-oxide, or an agriculturally acceptable salt thereof; and to mixtures comprising at least one such compound and at least one further pesticidally active substance selected from the group consisting of herbicides, safeners, fungicides, insecticides, and plant growth regulators; and to agrochemical compositions comprising at least one compound of the formula I and to agrochemical compositions further comprising seeds.

##STR00001##

Claims

1.-13. (canceled)

14. A compound of formula I, or its N-oxide or an agriculturally acceptable salt thereof, ##STR00014## wherein: R.sup.A is independently selected from the group consisting of halogen, cyano, C.sub.1-C.sub.6-alkyl, C.sub.1-C.sub.6-haloalkyl, C.sub.1-C.sub.6-alkoxy or C.sub.1-C.sub.6-haloalkoxy; n is 0, 1 or 2; L is S(O).sub.p; p is 0, 1 or 2; R.sup.1 is C.sub.1-C.sub.6-alkyl; and wherein the alkyl group is substituted with 1, 2, 3, 4, 5 or up to the maximum possible number of identical or different halogen atoms; and wherein the alkyl group is further unsubstituted or, in addition to the halogen atoms, substituted with 1, 2, 3 or up to the maximum possible number of identical or different radicals selected from the group consisting of cyano, C.sub.1-C.sub.6-alkyl, C.sub.1-C.sub.6-alkoxy and C.sub.3-C.sub.8-cycloalkyl; and wherein the cycloalkyl group is unsubstituted or substituted with 1, 2, 3 or 4 or up to the maximum possible number of halogen atoms; R.sup.2 is hydrogen, C.sub.1-C.sub.6-alkyl, C.sub.2-C.sub.6-alkenyl, C.sub.2-C.sub.6-alkynyl, C.sub.1-C.sub.6-alkoxy, C.sub.3-C.sub.8-cycloalkyl, C.sub.3-C.sub.8-cycloalkenyl, C.sub.3-C.sub.8-cycloalkyl-C.sub.1-C.sub.6-alkyl, phenyl-C.sub.1-C.sub.4-alkyl, phenyl, C(O)(C.sub.1-C.sub.6-alkyl) or C(O)(C.sub.1-C.sub.6-alkoxy); and wherein any of the aliphatic or cyclic groups are unsubstituted or substituted with 1, 2, 3 or up to the maximum possible number of identical or different radicals selected from the group consisting of halogen, cyano, C.sub.1-C.sub.6-alkyl, C.sub.1-C.sub.6-alkoxy and C.sub.3-C.sub.8-cycloalkyl; R.sup.3, R.sup.4 independently of each other are selected from the group consisting of hydrogen, halogen, cyano, C.sub.1-C.sub.4-alkyl, C.sub.1-C.sub.4-alkenyl, C.sub.1-C.sub.4-alkynyl, C.sub.1-C.sub.4-haloalkyl and C.sub.1-C.sub.4-alkoxy; or R.sup.3 and R.sup.4 together with the carbon atom to which they are bound form a saturated 3- to 7-membered carbocycle or a saturated 3- to 6-membered heterocycle; wherein the saturated heterocycle includes beside carbon atoms 1, 2 or 3 heteroatoms independently selected from the group consisting of N, O and S as ring member atoms; and wherein said N ring member atom is substituted with the group R.sup.N; and wherein R.sup.N is hydrogen, C.sub.1-C.sub.6-alkyl or halogen; and wherein said S ring member atom is unsubstituted or substituted with 1 or 2 oxo radicals; and wherein one or two CH.sub.2 groups of the saturated carbocycle or of the saturated heterocycle may be replaced by one or two groups independently selected from C(O) and C(S); and wherein the carbon ring member atoms of the saturated carbocycle or the saturated heterocycle are unsubstituted or substituted with a total number of 1, 2, 3, 4 or up to the maximum possible number of identical or different radicals selected from the group consisting of halogen, cyano, C.sub.1-C.sub.6-alkyl, C.sub.1-C.sub.6-alkoxy and C.sub.3-C.sub.8-cycloalkyl.

15. The compound of claim 14, wherein n is 0 or 1; and wherein R.sup.A is fluorine, chlorine, methyl or ethyl.

16. The compound of claim 14, wherein R.sup.3 and R.sup.4 are independently selected from hydrogen, halogen, C.sub.1-C.sub.6-alkyl or C.sub.1-C.sub.6-haloalkyl.

17. The compound of claim 14, wherein L is S(O).sub.2.

18. The compound of claim 14, wherein R.sup.2 is hydrogen, C.sub.1-C.sub.6-alkyl, C.sub.2-C.sub.6-alkenyl or C.sub.3-C.sub.8-cycloalkyl.

19. The compound of claim 14, wherein R.sup.2 is hydrogen, C.sub.1-C.sub.6-alkyl, C.sub.1-C.sub.6-alkenyl, C.sub.3-C.sub.8-cycloalkyl, C.sub.3-C.sub.8-cycloalkyl-C.sub.1-C.sub.4-alkyl; preferably hydrogen, methyl, ethyl, iso-propyl, cyclopropyl, CH.sub.2-cyclopropyl or allyl; and R.sup.1 is C.sub.3-C.sub.8-cycloalkyl-C.sub.1-C.sub.2-alkyl; and wherein any of the alkyl or cycloalkyl group in R.sup.1 are unsubstituted or substituted with 1, 2, 3 or 4 or up to the maximum possible number of radicals selected from the group consisting of chlorine and fluorine.

20. The compound of claim 14, wherein R.sup.2 is hydrogen, C.sub.1-C.sub.6-alkyl, C.sub.2-C.sub.6-alkenyl or C.sub.3-C.sub.8-cycloalkyl; and R.sup.1 is C.sub.1-C.sub.6-alkyl; and wherein the alkyl group in R.sup.1 is substituted with 1, 2, 3 or up to the maximum possible number of atoms selected from the group consisting of fluorine and chlorine.

21. Intermediate compounds of the formula VI or VII, ##STR00015## wherein the variables R.sup.A, n, L, R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are as defined in claim 14 for compounds of the formula I.

22. An agrochemical composition, which comprises an auxiliary and at least one compound of claim 14, or an N-oxide, or an agriculturally acceptable salt thereof.

23. An agrochemical composition according to claim 22, wherein the auxiliary is selected from the group of ionic or non-ionic surfactants.

24. An agrochemical composition according to claim 22, further comprising seed, wherein the amount of the compound of the formula I, or an N-oxide, or an agriculturally acceptable salt thereof, is from 0.1 g to 10 kg per 100 kg of seed.

25. A method for combating phytopathogenic harmful fungi, which process comprises treating the fungi, the plants, the soil or seeds to be protected against fungal attack, with an effective amount of at least one compound of formula I, or an N-oxide, or an agriculturally acceptable salt thereof, as defined in claim 14.

26. The method of claim 25, wherein n is 0 or 1; and wherein R.sup.A is fluorine, chlorine, methyl or ethyl.

27. The method of claim 25, wherein R.sup.3 and R.sup.4 are independently selected from hydrogen, halogen, C.sub.1-C.sub.6-alkyl or C.sub.1-C.sub.6-haloalkyl.

28. The method of claim 25, wherein L is S(O).sub.2.

29: The method of claim 25, wherein R.sup.2 is hydrogen, C.sub.1-C.sub.6-alkyl, C.sub.2-C.sub.6-alkenyl or C.sub.3-C.sub.8-cycloalkyl.

30. The method of claim 25, wherein R.sup.2 is hydrogen, C.sub.1-C.sub.6-alkyl, C.sub.1-C.sub.6-alkenyl, C.sub.3-C.sub.8-cycloalkyl, C.sub.3-C.sub.8-cycloalkyl-C.sub.1-C.sub.4-alkyl; preferably hydrogen, methyl, ethyl, iso-propyl, cyclopropyl, CH.sub.2-cyclopropyl or allyl; and R.sup.1 is C.sub.3-C.sub.8-cycloalkyl-C.sub.1-C.sub.2-alkyl; and wherein any of the alkyl or cycloalkyl group in R.sup.1 are unsubstituted or substituted with 1, 2, 3 or 4 or up to the maximum possible number of radicals selected from the group consisting of chlorine and fluorine.

31. The method of claim 25, wherein R.sup.2 is hydrogen, C.sub.1-C.sub.6-alkyl, C.sub.2-C.sub.6-alkenyl or C.sub.3-C.sub.8-cycloalkyl; and R.sup.1 is C.sub.1-C.sub.6-alkyl; and wherein the alkyl group in R.sup.1 is substituted with 1, 2, 3 or up to the maximum possible number of atoms selected from the group consisting of fluorine and chlorine.

Description

I. SYNTHESIS EXAMPLES

[0299] The compounds of formula I can be prepared according to the methods outlined below.

I.1) Preparation of 4-(methylaminomethyl)benzonitrile

[0300] To a solution of 4-(bromomethyl)benzonitrile (49 g, 1 eq.) in tetrahydrofuran (500 mL) methylamine (194 g of a 40% solution by weight, 10 eq.) was added. The mixture was stirred overnight at room temperature. After removing the solvent under reduced pressure, an aqueous solution of sodium chloride was added and the aqueous mixture was extracted with ethyl acetate. The combined organic layer was dried over magnesium sulfate and freed from solvent.

[0301] The title compound (35.6 g) was used directly without further purification.

I.2) Preparation of N-[(4-cyanophenyl)methyl]-2,2,2-trifluoro-N-methyl-ethanesulfonamide

[0302] To a solution of 4-(methylaminomethyl)benzonitrile (5.0 g, 1 eq.) and triethylamine (8.65 g, 2.5 eq.) in dichloromethane (100 mL) was added 2,2,2-trifluoroethanesulfonyl chloride (7.49 g, 1.2 eq.). The mixture was stirred at room temperature for two hours. Then ethyl acetate was added, the organic layer was washed with water, dried over sodium sulfate and concentrated in vacuo to yield the title compound (10.4 g) as yellow solid witch was used without further purification.

I.3) Preparation of N-hydroxy-4-[[methyl(2,2,2-trifluoroethylsulfonyl)amino]methyl]benzamidine

[0303] To a solution of N-[(4-cyanophenyl)methyl]-2,2,2-trifluoro-N-methyl-ethanesulfonamide (10.4 g, 1 eq.) in ethanol (200 mL) was added hydroxylammonium hydrochloride (4.95 g, 2 eq.), then triethylamine (9.0 g, 2.5 eq.). The mixture was stirred at room temperature for 4 hours. After removing the solvent under reduced pressure, the crude product was used without further purification.

I.4) Preparation of 2,2,2-trifluoro-N-methyl-N-[[4-[5-(trifluoromethyl)-1,2,4-oxadiazol-3-yl]phenyl]methyl]ethanesulfonamide (Ex-2)

[0304] To a solution of N-hydroxy-4-[[methyl(2,2,2-trifluoroethylsulfonyl)amino]methyl]benzamidine (0.86 g, 1 eq.) in dichloromethane (10 mL) trifluoroacetic anhydride (0.98 g, 4 eq.) was added. After stirring over night at room temperature the mixture was extracted with an aqueous solution of sodium bicarbonate, dried over sodium sulfate and concentrated in vacuo. The crude product was purified by flash chromatography to yield the title compound as yellow solid (0.15 g, 30%) (Ex-2). .sup.1H NMR (CDCl.sub.3, 500 MHz): [ppm]=8.18 (d, 2H), 7.55 (d, 2H), 4,48 (s, 2H), 3.86 (q, 2H), 2.88 (s, 3H).

[0305] The compounds listed in Table I were prepared in analogy to the procedures described above.

TABLE-US-00003 TABLE I Compounds Ex-1 to Ex-15 of formula I.F, wherein the meaning of radicals R.sup.1 and R.sup.2 is as defined in each line. Ex. HPLC Rt Melting no R.sup.2 R.sup.1 (min)* point ( C.) Ex-1 CH.sub.3 CH.sub.2CF.sub.2CH.sub.3 1.228 92 Ex-2 CH.sub.3 CH.sub.2CF.sub.3 1.268 115 Ex-3 CH.sub.3 CH(CF.sub.3)CH.sub.3 1.291 110 Ex-4 CH.sub.3 CH.sub.2CHF.sub.2 1.228 92 Ex-5 CH.sub.2CH.sub.3 CH.sub.2CF.sub.3 1.300 97 Ex-6 CH.sub.2CH.sub.3 CH(CF.sub.3)CH.sub.3 1.321 110 Ex-7 CH.sub.2CH.sub.3 CH.sub.2CHF.sub.2 1.263 76 Ex-8 CH.sub.2CH.sub.3 CH.sub.2CF.sub.2CH.sub.3 1.269 88 Ex-9 cyclopropyl CH.sub.2CF.sub.3 1.321 108 Ex-10 cyclopropyl CH(CF.sub.3)CH.sub.3 1.336 83 Ex-11 cyclopropyl CH.sub.2CHF.sub.2 1.254 62 Ex-12 cyclopropyl CH.sub.2CF.sub.2CH.sub.3 1.284 90 Ex-13 allyl CH.sub.2CF.sub.3 1.272 124 Ex-14 allyl CH.sub.2CHF.sub.2 1.263 96 Ex-15 allyl CH.sub.2CF.sub.3 1.331 73 *HPLC: High Performance Liquid Chromatography; HPLC-column Kinetex XB C18 1.7 (50 2.1 mm); eluent: acetonitrile/water + 0.1% trifluoroacetic acid (gradient from 5:95 to 100: 0 in 1.5 min at 60 C., flow gradient from 0.8 to 1.0 ml/min in 1.5 min). MS: Quadrupol Electrospray Ionisation, 80 V (positive mode). R.sub.t: retention time in minutes.

II. BIOLOGICAL EXAMPLES FOR FUNGICIDAL ACTIVITY

[0306] The fungicidal action of the compounds of formula I was demonstrated by the following experiments:

[0307] A. Glass House Trials

[0308] The spray solutions were prepared in several steps: The stock solution were prepared: a mixture of acetone and/or dimethylsulfoxide and the wetting agent/emulsifier Wettol, which is based on ethoxylated alkylphenoles, in a relation (by volume) solvent to emulsifier of 99 to 1, was added to 25 mg of the compound to give a total of 5 ml. Water was then added to total volume of 100 ml. This stock solution was diluted with the described solvent-emulsifier-water mixture to the given concentration.

[0309] A.1. Curative Control of Soy Bean Rust on Soy Beans Caused by Phakopsora pachyrhizi

[0310] Leaves of pot-grown soy bean seedlings were inoculated with spores of Phakopsora pachyrhizi. To ensure the success of the artificial inoculation, the plants were transferred to a humid chamber with a relative humidity of about 95% and 20 to 24 C. for 24 hours. The next day the plants were cultivated for 3 days in a greenhouse chamber at 23 to 27 C. and a relative humidity between 60 and 80%. Then the plants were sprayed to run-off with an aqueous suspension, containing the concentration of active ingredient or their mixture as described below. The plants were allowed to air-dry. Then the trial plants were cultivated for 14 days in a greenhouse chamber at 23 to 27 C. and a relative humidity between 60 and 80%. The extent of fungal attack on the leaves was visually assessed as % diseased leaf area.

[0311] In this test, the plants which had been treated with 16 ppm of the active compounds Ex-1 and Ex-2 showed a diseased leaf area of at most 5%, whereas the untreated plants showed 90% diseased leaf area.

[0312] A.2. Protective Control of Soy Bean Rust on Soy Beans Caused by Phakopsora pachyrhizi

[0313] Leaves of pot-grown soy bean seedlings were sprayed to run-off with an aqueous suspension, containing the concentration of active ingredient or their mixture as described below. The plants were allowed to air-dry. The trial plants were cultivated for 2 days in a greenhouse chamber at 23 to 27 C. and a relative humidity between 60 and 80%. Then the plants were inoculated with spores of Phakopsora pachyrhizi. To ensure the success the artificial inoculation, the plants were transferred to a humid chamber with a relative humidity of about 95% and 20 to 24 C. for 24 hours. The trial plants were cultivated for fourteen days in a greenhouse chamber at 23 to 27 C. and a relative humidity between 60 and 80%. The extent of fungal attack on the leaves was visually assessed as % diseased leaf area.

[0314] In this test, the plants which had been treated with 16 ppm of the active compounds Ex-1 and Ex-2 showed a diseased leaf area of at most 3%, whereas the untreated plants showed 90% diseased leaf area.

[0315] 4. Preventative Control of Brown Rust on Wheat Caused by Puccinia recondita

[0316] The first two developed leaves of pot-grown wheat seedling were sprayed to run-off with an aqueous suspension, containing the concentration of active ingredient or their mixture as described below. The next day the plants were inoculated with spores of Puccinia recondita. To ensure the success the artificial inoculation, the plants were transferred to a humid chamber without light and a relative humidity of 95 to 99% and 20 to 24 C. for 24 hours. Then the trial plants were cultivated for 6 days in a greenhouse chamber at 20 to 24 C. and a relative humidity between 65 and 70%. The extent of fungal attack on the leaves was visually assessed as % diseased leaf area.

[0317] In this test, the plants which had been treated with 63 ppm of the active compounds Ex-1 and Ex-2 showed a diseased leaf area of at most 4%, whereas the untreated plants showed 80% diseased leaf area.