Claims
- 1. A compound of the formula ##STR16## in which R' is methyl, chlorine, bromine or methoxy;
- R" is methyl, chlorine or bromine; and
- R"' is C.sub.1 -C.sub.3 -alkyl that is substituted by 1 to 3 fluorine atoms, and
- m is 0 or 1,
- n is 0 or 1, X.sub.1 and X.sub.2 independently of the other, is oxygen or sulfur.
- 2. A compound of claim 1 in which
- R' is methyl, chlorine, bromine or methoxy;
- R" is methyl, chlorine or bromine; and
- R"' is CHF.sub.2 ; and
- m is 0 or 1.
- 3. A compound of claim 1 selected from the group consisting of
- 2-difluoromethylthio-5-thien-2-yl-1,3,4-thiadiazole,
- 2-difluoromethylthio-5-(5-chlorothien-2-yl)-1,3,4-thiadiazole,
- 2-difuloromethylthio-5-(5-methylthien-2-yl)-1,3,4-thiadiazole,
- 2-difluoromethylthio-5-(5-bromothien-2-yl)-1,3,4-thiadiazole,
- 2-difluoromethylthio-5-thien-2-yl-1,3,4-oxadiazole,
- 2-difluoromethylthio-5-(chlorothien-2-yl)-1,3,4-oxadiazole,
- 2-difluoromethylthio-5-(5-methylthien-2-yl)-1,3,4-oxadiazole,
- 2-difluoromethylthio-5-(furan-2-yl)-1,3,4-thiadiazole,
- 2-difluoromethylthio-5-(2-methylfuran-3-yl)-1,3,4-thiadiazole,
- 2-difluoromethylthio-5-(4-methylthien-2-yl)-1,3,4-thiadiazole, and
- 2-difluoromethylthio-5-(furan-2-yl)-1,3,4-oxadiazole.
- 4. An anti-nematodal composition comprising an agriculturally-acceptable carrier and an effective nematocidal amount of at least one compound of the formula ##STR17## in which R' is methyl, chlorine, bromine or methoxy;
- R" is methyl, chlorine or bromine; and
- R"' is C.sub.1 -C.sub.3 -alkyl that is substituted by 1 to 3 fluorine atoms, and
- m is 0 or 1,
- n is 0 or 1, X.sub.1 and X.sub.2 independently of the other, is oxygen or sulfur.
- 5. A composition of claim 4, which contains 0.1 to 99% of a compound of the formula, 99.9 to 1% of a solid or liquid carrier and 0 to 25% of a surfactant.
- 6. A composition of claim 5, which contains from 0.1 to 95% of a compound of the formula, 99.8% to 5% of a solid or liquid carrier and from 0.1 to 25% of a surfactant.
- 7. A method of controlling or preventing an attack on cultivated plants by nematodes, comprising the step of applying a compound of the formula ##STR18## in which R' is methyl, chlorine, bromine or methoxy;
- R" is methyl, chlorine or bromine; and
- R"' is C.sub.1 -C.sub.3 -alkyl that is substituted by 1 to 3 fluorine atoms, and
- m is 0 or 1,
- n is 0 or 1, X.sub.1 and X.sub.2 independently of the other, is oxygen, or sulfur.
- 8. The method of claim 7 wherein the nematodes are of a species that parasitizes plants.
- 9. The method of claim 8 wherein the nematodes are of the genera Meloidogyne, Heterodera or Globodera.
Priority Claims (1)
| Number |
Date |
Country |
Kind |
| 3870/86 |
Sep 1986 |
CHX |
|
Parent Case Info
This application is a continuation of application Ser. No. 095,728, filed 9/14/87, now abandoned.
The present invention relates to novel substituted 2-mercapto-5-furyl-1,3,4-oxadiazole and 2-mercapto-5-furyl-1,3,4-thiadiazole derivatives, and also 2-mercapto-5-thienyl-1,3,4-oxadiazole and 2-mercapto-5-thienyl-1,3,4-thadiazole derivatives, to the preparation thereof and to nematocidal compositions containing as active ingredient at least one of those compounds. The invention also relates to the use of the novel active ingredients and compositions for the control of nematodes, especially nematodes that damage plants.
The compounds according to the invention correspond to the general formula I ##STR2## in which
R' represents C.sub.1 -C.sub.5 -alkyl, halogen, trifluoromethyl or C.sub.1 -C.sub.3 -alkoxy;
Alkyl, as an independent radical or as a part of another group, such as alkoxy, is to be understood as a straight-chain or branched alkyl group. This includes the methyl and ethyl group and the isomers of the propyl, butyl and pentyl group, and of these especially methyl, ethyl, n-propyl, isopropyl, isobutyl or n-pentyl. Halosubstituted alkyl is a mono- to per-halogenated alkyl radical, such as, for example, CHCl.sub.2, CH.sub.2 F, CCl.sub.3, CH.sub.2 Cl, CHFCH.sub.3, CH.sub.2 CH.sub.2 Br, CF.sub.2 CF.sub.3, C.sub.2 Cl.sub.5, CH.sub.2 Br, CHBrCl etc., and is preferably CF.sub.3 or CHF.sub.2. Alkenyl is, for example, propen-1-yl, allyl, buten-1-yl, buten-2-yl or buten-3-yl and chains with several double bonds. Alkynyl is, for example, propyn-2-yl, butyn-1-yl, butyn-2-yl, pentyn-4-yl etc., but is preferably propargyl. Halogen is fluorine, chlorine, bromine or iodine, preferably fluorine, chlorine or bromine.
Oxadiazole and thiadiazole derivatives that have been described as nematocidally active are already known. Such compounds with a 1,2,4-position of the hetero atoms are disclosed in U.S. Pat. Specification No. 3,770,754, whilst U.S. Pat. Specification No. 4,454,147 describes 1,3,4-thiadiazole derivatives in which, compared with the compounds of the invention, the heterocycle instead of the mercapto groups is substituted by a chlorine atom. These known compounds have hitherto, as nematocides, not been able fully to meet the demands made upon them in practice. Also, oxadiazole derivatives with a fungicidal activity are described in DE-OS No. 2 361 613. There is not, however, mentioned expressis verbis therein any of those compounds that fall within the scope of formula I according to the invention.
By making available the compounds of formula I according to the invention it is now possible to make a valuable contribution to controlling plant nematodes that cause considerable agricultural damage to the crop. In the manner it is possible for losses in yield in cultivated plants such as, for example, potatoes, cereals, beets, rape, cabbage, tobacco, soybeans, cotton and vegetatbles, and damge in tree nurseries and in ornamental plant nurseries to be checked effectively. The compounds according to the invention are distinguished especially by their effective control of root parasite soil nematodes such as, for example, those of the genera Heterodera and Globodera (cyst-forming nematodes), Meloidogyne (root knot nematodes) and of the genera Radopholus, Pratylenchus, Tylenchulus, Longidorus, Trichodorus, and Xiphinema. It is also possible with the active ingredients of the invention effectively to control the nematode genera Ditylenchus (stem parasites), Aphelenchoides (leaf nematodes) and Anguina (blossom nematodes).
With the active ingredients of the formula I it is preferably possible successfully to control especially harmful species of nematodes of the genus Meloidogyne, such as, for example, Meloidogyne incognita, and of the genus Heterodera, such as, for example, Heterodera glycines (soybean cyst nematode) and also of the genus Globodera, such as, for example, Globodera rostochiensis (potato cyst nematode) and also representatives of migrating endoparasites, such as, for example, Pratylenchus penetrans or Radopholus similis and representatives of ectoparasites, such as, for example, Trichodorus spp. and Xiphinema spp..
The novel active ingredients can be used curatively, preventatively or systemically to control plant nematodes and to keep the crop healthy. They have a broad spectrum of activity against the various species of nematodes and consequently meet the practical requirements. The nematocidal mode of action of the compounds of the invention is advantageously accompanied by a low phytotoxicity so that the general desirability of a reduction in pollution of the environment is achieved to a substantial extent.
Within the scope of the present invention, the following compound groups of the formula I are preferred:
(3) Compounds in which
(4) Compounds in which
(5) Compounds in which
(6) Compounds in which
(7) Compounds in which
The following compounds are preferred:
Compounds of the formula I are prepared in accordance with the invention as follows:
(a) in a condensation reaction, a compound of the formula IIa ##STR3## or a compound of the formula IIb ##STR4## is reacted with a compound of the formula IIIa
(b) in an addition reaction, a compound of the formula IIa ##STR5## is reacted with a compound of the formula IIIb ##STR6## in an inert solvent or mixture of solvents at elevated temperature, optionally in the presence of a catalyst and optionally at elevated pressure, this reaction resulting in a compound of the formula Ia ##STR7## or a compound of the formula Ib ##STR8##
In the above formulae IIa, IIB, Ia, Ib, IIIa and IIIB, Me represents an alkali metal or amminium, Hal represents halogen, preferably chlorine, bromine or iodine, and R"" represents fluorine or trifluoromethyl, whilst R', R", R"', m, n, X.sub.1 and X.sub.2 are as defined for formula I.
Suitable solvents or diluents for the preparation of the active ingredients of the invention are, for example, ethers and ethereal compounds such as dialkyl ethers (diethyl ether, diisopropyl ether, tert.-butylmethyl ether etc.), anisole, dioxan and tetrahydrofuran; aliphatic and aromatic hydrocarbons such as benzene, toluene and petroleun ether; halogenated hydrocarbons such as chlorobenzene, methylene chloride, chloroform, ethylene chloride, carbon tetrachloride and tetrachloroethylene; nitriles such as acetonitrile and propionitrile; N,N-dialkylated amides such as dimethylformamide; dimethyl sulphoxide; ketones such as acetone, diethyl ketone, methyl ethyl ketone and also water and alcohols such as, for example, methanol, ethanol, isopropanol or butanol; and, quite generally, mixtures of such solvents with one another.
Suitable bases are organic and inorganic bases, for example preferably tertiary amines such as trialkylamines (trimethylamine, triethylmaine, tripropylamine etc.), and also oxides, hydroxides, carbonates and hydrogen carbonates of alkali metals and alkaline earth metals (for example CaO, BaO, NaOH, KOH, Ca(OH).sub.2, KHCO.sub.3, NaHCO.sub.3, Ca(HCO.sub.3).sub.2, K.sub.2 CO.sub.3, Na.sub.2 CO.sub.3 etc.), and also acetates such as, for example, CH.sub.3 COONa or CH.sub.3 COOK. Also suitable as bases are alkali alcoholates such as, for example, sodium ethoxide, sodium propoxide, potassium tert.-butoxide or sodium methoxide.
The addition of catalytic amounts of a Crown ether such as, for example, 18-Crown-6- or 15-Crown-5-, has a favourable effect on the course of the reaction in the preparation process. Also, the catalytic use of tetraalkylamine salts, for example tetraalkylammonium hydrochlorides or hydrobromides, preferably tetra-n-butylammonium hydrobromide, has proved advantageous for the same purpose. Furthermore, alkali iodides, preferably potassium iodide, may advantageously be used as catalysts.
The reaction temperatures in the preparation processes are from 10.degree. to 90.degree. C., preferably from 30.degree. to 80.degree. C. Pressures of from 1 to 20 bars, preferably from 6 to 14 bars, are standard for the pressure conditions during the course of the reaction.
The invention relates also to compositions for the control of nematodes that damage plants, and for the prevention of attack on the crop by nematodes, that contain the active ingredients of the formula I.
Furthermore, the present invention includes, in addition, the preparation of nematocidal compositions which is characterised by the intimate mixing of active ingredients of the formula I with one or more carriers and adjuvants described herein. Also included is a method for the treatment of plants which is characterised by the application of the compounds of the formula I or the novel compositions.
Some of the starting compounds of the formula IIa and IIB are known. The novel compounds of the said formulae are intermediates for the preparation of valuable nematocidal active ingredients (see Table O) and therefore the present invention relates also to these.
The starting compounds of the formula IIa and IIB may be prepared according to known methods, as follows:
(a) 2-Mercapto-1,3,4-oxadiazoles can be obtained by adding carbon disulphide to a solution of the correspondingly substituted furoyl or thenoyl hydrazide in aqueous alcoholic potassium hydroxide and heating the reaction mixture for a few hours. The solvents used for this are alcohols such as, for example, ethyl alcohol or n-amyl alcohol. The free mercapto compounds are obtained by acidifying the resulting potassium salts [see J. Am. Chem. Soc. 78, 4975-4978 (1956)].
(b) 2-Mercapto-1,3,4-thiadiazoles can be obtained by treating the correspondingly substituted furoyl or thenoyl potassium dithiocarbazate with concentrated sulphuric acid at -5.degree. to 10.degree. C. [see J. prakt. Chem. 93, 49 (1916); J. Org. Chem. 23, 1021 (1958); J. Heterocycl. Chem. 19, 542-544 (1982)].
Some of the starting compounds of the formulae IIa and IIb are novel substances that, as intermediates for the preparation of valuable useful end products of the formula I, are a further aspect of the present invention (for example the compounds of Table O).
A preferred method for the use of an active ingredient of the formula I or a nematocidal composition that contains at least one of these active ingredients is the introduction thereof into the soil. For this the locus of the plants is treated with a liquid or solid preparation.
The compounds of the formula I can alternatively, however, be applied to the seed grains (coating) by either soaking the grains in a liquid preparation of the active ingredient or coating them with a solid preparation. Furthermore, in special cases other methods of application are possible, for example the directed treatment of the plant stems, buds or leaves.
Active ingredients of the formula I are customarily used in the form of formulated compositions and may be applied to the areas or plants to be treated simultaneously with or in succession to further active ingredients. These further active ingredients may also include other compositions used in agriculture that in their practical application serve to increase production by promoting the growth of the useful plants, such as fertilizers, herbicides, insecticides, fungicides, molluscicides inter alia, or mixtures of several of these preparations, together with, if desired, other carriers, surfactants or other application-promoting additives customary in the art of formulation.
Suitable carriers and additives may be solid or liquid and correspond to substances appropriate in the art of formulation, such as, for example, natural or regenerated mineral substances, solvents, dispersing agents, wetting agents, tackifiers, thickeners, binders or fertilisers.
The compounds of the formula I are used in unmodified form or, preferably, together with adjuvants customary in the art of formulation. They are processed in known manner, for example, into emulsifiable concentrates, directly sprayable or dilutable solutions, dilute emulsions, wettable powders, soluble powders, dusts, granulates, and encapsulations in, for example, polymeric substances. As with the nature of the compositions, the methods of application, such as spraying, dusting, scattering or pouring, are chosen in accordance with the intended objectives and the prevailing circumstances. Favourable rates of application are generally from 500 g to 6 kg of active ingredient per hectare, preferably from 1 to 4 kg of active ingredient/ha.
The formulations, that is to say the compositions, preparations or formulations containing the active ingredient of the formula I and, where appropriate, a solid or liquid adjuvant, are prepared in known manner, for example by intimate mixing and/or grinding of the active ingredients with extenders, such as, for example, solvents, solid carriers and, where appropriate, surfaceactive substances (surfactants).
Suitable solvents are: aromatic hydrocarbons, preferably the fractions C.sub.8 -C.sub.12, such as, for example, xylene mixtures or substituted naphthalenes, phthalic acid esters such as dibutyl or dioctyl phthalate, aliphatic hydrocarbons such as cyclohexane or paraffins, alcohols and glycols and ethers and esters thereof, such as ethanol, ethylene glycol, ethylene glycol monomethyl or monoethyl ether, ketones such as cyclohexanone, strongly polar solvents such as N-methyl-2-pyrrolidone, dimethyl sulphoxide or dimethylformamide, and also vegetable oils which may be epoxidised, such as epoxidised coconut oil or soybean oil, or water.
The solid carriers used, for example for dusts and dispersible powders, are normally powdered natural minerals, such as calcite, talcum, kaolin, montmorillonite or attapulgite. In order to improve the physical properties it is also possible to add highly dispersed silicic acid or highly dispersed absorbent polymers. Suitable granulated adsorptive carriers are porous types such as, for example, pumice, broken brick, sepiolite or bentonite, and suitable non-sorbent carrier materials are, for example, calcite or sand. Furthermore, a large number of pre-granulated materials of inorganic or organic nature can be used such as, especially, dolomite or pulverised plant residues.
Depending upon the nature of the active ingredient of the formula I to be formulated, suitable surface-active substances are non-ionic, cationic and/or anionic surfactants having good emulsifying, dispersing and wetting properties. The term surfactants is also to include mixtures of surfactants.
Suitable anionic surfactants can be either so-called water-soluble soaps or water-soluble synthetic surfaceactive compounds.
As soaps there may be mentioned alkali metal, alkaline earth metal or substituted or unsubstituted ammonium salts of higher fatty acids (C.sub.10 -C.sub.22) such as, for example, the sodium or potassium salts of oleic or stearic acid, or of mixtures of natural fatty acids that can be obtained, for example, from coconut oil or tallow oil. Fatty acid methyltaurin salts should also be mentioned.
More frequently, however, so-called synthetic surfactants are used, especially fatty sulphonates, fatty sulphates, sulphonated benzimidazole derivatives or alkylarylsulphonates.
The fatty alcohol sulphonates or sulphates are generally in the form of alkali metal, alkaline earth metal or substituted or unsubstituted ammonium salts and contain an alkyl radical having from 8 to 22 carbon atoms, alkyl also including the alkyl moiety of acyl radicals, for example the sodium or calcium salt of lignosulphonic acid, of dodecylsulphuric acid ester or of a mixture of fatty alcohol sulphates produced from natural fatty acids. Also included are the salts of sulphuric acid esters and sulphonic acids of fatty alcohol/ethylene oxide adducs. The sulphonated benzimidazole derivatives preferably contain 2 sulphonic acid groups and a fatty acid radical having from 8 to 22 carbon atoms. Alkylarylsulphonates are, for example, the sodium, calcium or triethanolamine salts of dodecylbenzenesulphonic acid, of dibutylnaphthalenesulphonic acid or of naphthalenesulphonic acid/formaldehyde condensation product.
There also come into consideration corresponding phosphates such as, for example, salts of the phosphoric acid ester of an adduct of p-nonylphenol with from 4 to 14 mols of ethylene oxide.
Non-ionic surfactants are especially polyglycol ether derivatives of aliphatic or cycloaliphatic alcohols, of saturated or unsaturated fatty acids and alkylphenols, which derivatives may contain from 3 to 30 glycol ether groups and from 8 to 20 carbon atoms in the (aliphatic) hydrocarbon moiety and from 6 to 18 carbon atoms in the alkyl moiety of the alkylphenols.
Further suitable non-ionic surfactants are the watersoluble adducts of polyethylene oxide with polypropylene glycol, ethylenediamine polypropylene glycol and alkylpolypropylene glycol containing from 1 to 10 carbon atoms in the alkyl chain, which adducts contain from 20 to 250 ethylene glycol ether groups and from 10 to 100 propylene glycol ether groups. The compounds mentioned usually contain from 1 to 5 ethylene glycol units per propylene glycol unit.
There may be mentioned as examples of non-ionic surfactants nonylphenolpolyethoxyethanols, castor oil polyglycol ethers, polypropylene/polyethylene oxide adducts, tributylphenoxypolyethoxyethanol, polyethylene glycol and octylphenoxypolyethoxyethanol.
Fatty acid esters of polyoxyethylene sorbitan, such as polyoxyethylene sorbitan trioleate, also come into consideration.
The cationic surfactants are especially quaternary ammonium salts that contain, as N-substituent, at least one alkyl radical having from 8 to 22 carbon atoms and, as further substituents, lower, optionally halogenated alkyl, benzyl or lower hydroxyalkyl radicals. The salts are preferably in the form of halides, methyl sulphates or ethyl sulphates, for example stearyltrimethylammonium chloride or benzyldi-(2-chloroethyl)-ethylammonium bromide.
The agrochemical preparations generally contain from 0.1 to 99% by weight, especially from 0.1 to 95% by weight, of active ingredient of the formula I, from 99.9 to 1% by weight, especially from 99.8 to 5% by weight, of a solid or liquid adjuvant and from 0 to 25% by weight, especially from 0.1 to 25 % by weight, of a surfactant.
Whilst as commercial products concentrated formulations will be preferred, the end user generally uses dilute formulations.
The compositions may also contain further additives, such as stabilisers, anti-foams, viscosity regulators, binders, tackifiers and fertilisers, or other active ingredients for achieving specific effects.
The present invention relates also to such agrochemical compositions.
The following Examples serve to illustrate the invention in detail without implying any limitation.
US Referenced Citations (2)
Foreign Referenced Citations (1)
| Number |
Date |
Country |
| 8607590 |
Dec 1986 |
WOX |
Non-Patent Literature Citations (1)
| Entry |
| Orerte, Ann Chim 53 1687 (1963), abstract. |
Continuations (1)
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Number |
Date |
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| Parent |
95728 |
Sep 1987 |
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Patent Grant
4861787
