CA2137686A1 - Benzimidazole derivatives as microbicides - Google Patents

Abstract

Compounds of formula (I) in which R1 is CN or -CS(=O)nNH2, R2 is C1-C4alkyl, C3-C6cycloalkyl or -N(R')2, in which R' radicals are different or identical C1-C3alkyl radicals and n is 0 or 1, are suitable for controlling and preventing infestation of plants by microorganisms. They can be used in the form of commercially available formulations.

Description

~137~
'0 94/01411 PCr/EP93/01660 sENz~Tr~A7~F DER CVATIVES A~

The present invention relates to novel bemimid~7.01es1-1fonic acid derivatives of the formula I below. It furthP.rmore relates to the preparation of these subst~n~es and to agroch~mic~lc co npri.~ing at least one of these compounds as active ingredient. The invention also relates to the preparation of tne abovementioned compositio~.~ and to the use of the active ingredients or of the compositions for controlling or preventing infest~tion of plants by phytopathogenic microorg~ni.cm.~, preferably fungi.

The compounds according to the invention are those of the general formula I

F3C/J~2R2 (I) in which the R2SO2 group is in the 1- or 3-position and causes the formation of pure or mixed po.cition~l isomers relative to the CF3 substitllent~ and in which the substituent~c are as defined below:

Rl is CN or -CS(=O)nNH2.
R2 is Cl-C4a~yl, C3-C6cycloaLkyl or -N(R')2, in which R' substituent~ are dirîe,ent or identic~l Cl-C3aLkyl radicals, and n is 0 or l.

The term aL~yl itself or as a component of another substituent is to be understood as m~.~ning the following straight-chain or branched groups, depending on the number of the carbon atoms indicated: met'nyl, èthyl, propyl, butyl and their isomers isopropyl, isobutyl, sec-butyl and tert-butyl.

At room temperature, the compounds of the formula I are stable solids which are distinguished by valuable microbicidal properties. Their particularly advantageous activity WO 94/01411 ~ 37 6 ~ ~ PCr/EP93/0166--is based mainly on the specific substitution pattern in the fused benzene ring. They can be used in a preventive and curative fashion in the field of agriculture or related fields for controlling phytopathogenic microorg~nicms Used at low concentrations, the active ingredients of the formula I according to the invention are distinguished not only by an outct~ntling microbicidal, in particular filngicjd~l, activity, but also by the fact that they are particularly well tolerated by plants.

Important compounds within the scope of the formula I are those in which R2 is Cl-C2aL~yl, cyclopropyl or N(R')2, R' is methyl or ethyl and n is 0 or 1.

One of the particularly important sllbst~nce groups within this scope is the group in which R2 is methyl or N(R')2, R' is methyl and n is 0 or 1. Particularly preferred compounds from amongst this group are those in which R2 is dimethylamino and n is 0 or 1.

A group of p-efel,t;d compounds of the formula I embraces the compounds in which the R2SO2 group is in the 1- or 3-position and causes the formation of pure or mixedposhion~l isomers relative to the CF3 substi~uent.c and in which Rl is -CSNH2 and R2 is Cl-C4aL~cyl, C3-C6cycloaL~cyl or -N(R')2, in which R' substituçnt~c are dirrel~nt or identir~l Cl-C3aLkyl r~iç~lc. Particularly preferred from amongst these substituçntc are those in which R2 is methyl or -N(CH3)2.

Preferred individual compounds are 1 (3)-dimethyl~minosulfonyl-2-carbothio~mido-4,6-bi.ctrifluQromethylbçn7imi(i~7.01e, 1(3)-dimethylaminosulfonyl-2-carbothioamido-4,6-bistrifluoromethylbenzimidazole-S-oxide and 1 (3)-dimethylaminosulfonyl-2-cyano-4,6-bistrifluoromethylbe~7imi~7ole.

If n is 0 (formula Ib), the compounds of the formula I where Rl is -CS(=O)nNH2 can be prepared by reacting H2S with a compound of the formula Ia, F9C NN`~SOCFN2 (la) in which R2 is as defined in formula I. The reaction which leads to the thioamide is carried 0 94/01411 . PCr/EP93/01660 7Ç$~ ~

out in the presence of inorganic or organic bases. Preferred substances are organic bases, for example sec-amines such as dimethylamine [K. Kindler, Ann. 431, 187 (1923)], diethylamine or tert-amines such as triP.thAnQlAmine or triethylamine [J.F. Olin and T.B.
Johnson, R. 50, 72 (1931); D.W. McCorquodale and T.B. Johnson, R. 51, 483 (1932)].
Equimolar amounts or a slight excess of bases are preferably used. The following act as solvents: polar solvents, for example alcohols (meth~nol, ethanol, isoplopal1ol etc.), but preferably acid Ami~les, for e~r~mplP. dimethylformamide, or else ethers such as diethyl ether, tetrahydrofuran, tliol~AnP~ etc.

A further pos.cibility for adding on H2S is the use of heterocyclic bases as the solvent, for example pyridine, in the presence of a tert-amine, such as trialkylamine (for example triethylamine lA.E.S. Fairfull, J.L. Lowe and D.A. Peak, Soc. 1952, 742]. H2S is passed in at -20C to +80C, in particular -10C to +40C. H2S can be passed in continuously, or the process can be carried out under ples~ule.

The S-oxide co-"pounds (n = 1, formula Ic) are prepared from the thioamides (n = 0, forrnula Ib) by oxi~tion with organic peroxides or hydrogen peroxide (preferably in the form of an aqueous 30% sollltinn). Appr--~i.l-At~ly equimolar amounts of oxi(lAnt are preferably used. The following act as solvents: polar solvents, for example alcohols (methanol, iso~ )panol), acid amides (N-methylpyrrolidone), ketones (~cet~tnP), pyridine, or aliphatic carboxylic acids. The preferred substance is acetic acid (glacial acetic acid), with or without an Ad~lition of a base, for example sodium acetate. The reactiontemperature is between -20C and +60C, preferably between 0C and +30C.

F3C ~C N~2 ~ ~cN ~jD

(Ib, n = 0) (Ic, n = 1) The invention also relates to 2-cyano-4,6-bistrifluoromethylbenzimidazole of theformula III and to the preparation thereof. The substance is prepared from 1,2-diamino-3,5-bistrifluoromethylbenæne or salts thereof by methods known per se:

WO 94/01411 ~i 3 7 6 8 6 PCr/EP93/0166C--a) ~NH+2 HN~ 3 -NH4Y

F3C NH2(.HY) Trihaloimidate -ROH
= anion of an acid; Hal = halogen, preferably Cl; R = Cl-C3aL~cyl) F9CJ~C ~CHal3 ~ XNH3 3NH~Hal ~C ~CN (111) HY is an inorganic or organic acid, preferably a hydrohalic acid or sulfuric acid. The o-phenylPnP~i~minp deAvative can, however, also be used in the form of the free base when reaction step a) is carried out in glacial acetic acid. l?~erell~d solvents other than glacial acetic acid are ethers such as diethyl ether, ~io~r~nP~ 1,2-dimethoxyethane; esters such ethyl acetate, or alcohols such as rneth~nol and eth~nol.

The trih~loimi~te (for e~r~mrl~q. methyl trichloromethylimill~tP. or chlorodifluoromethylimi~tP.) is advantageously added to the dissolved or suspended o-phenylPnPdi~minP derivative at-20C to +100C. In reaction step b), the 2-trihalomethylben7.imi(1~7.olP derivative obtained is advantageously added to aconcentr~tP.d aqueous ammonia solution (USP. 3 576 818).

2-Cyano-4,6-bi.~trifl~loromethylben7.imitl~7.ole, of the formula III, can also be prepared using the corresponding 2-nitro-4,6-bistrifluoromethylaniline in place of the o-phenylenP,di~mine derivative by reacting it with f~rm~klehyde and KCN in glacial acetic acid with ~l(lition of _inc chloride (or a different Lewis acid) as catalyst, giving compounds of the formula ~_ NH- CH2--CN

F3C ~J--N02 ~O 94/01411 2,~ 3 7 6 ~ 6 ~ PCr/EP93/01660 [K. Dimroth et al., Ber. 98, 3902 (1965)~, and these are cyclised with K2CO3 to give 1-hydroxy-2-cyanoben7imi~701e derivatives [B. Serafinowa et al. Rocz. Chem. 51, 1783 (1977)], which can be reacted with PCl3 to give compounds of the formula III. This process variant is also an object of the invention.

The products of the formula Ia can be prepared by reacting the compound of the formula m or one of the alkali metal salts thereof, preferably a sodium, pot~ m or lithium salt, with a compound of the formula IV

Q-S02-R2 (IV) in which R2 is as defined in formula I and Q is a halogen atom, preferably chlorine or bromine, or the radical O-~O2-R2, in an inert solvent in the presence or absence of a base at tempe,a~ult;s from -30 to ~180C, preferably -10 to +80C.

Suitable solvents are, in particular, polar reaction media such as k~tonps (for ~Y~mpl~
~eton~, methyl ethyl ketone or tert-butyl methyl ketone), ethers (such as diethyl ether, dioxane, tetrahydrofuran or 1,2-dimethoxyethane), amides (for example dimethylform~mide) or dimethylsulfoxide or, if applupliate, mi~ules of such solvents.
The ben7imid~7ole derivative III is advantageously reacted in the presence of a strong base (such as KOH or NaOH).

Surprisingly, it has been found that compounds which have the specific structural pattern of the formula I have a biocidal spectrum which is highly favourable for practical requirements for controlling phytopathogenic microor~ni~m.~, in particular fungi. They have very advantageous curative and preventative properties and are used for theprotection of a large number of crop plants. The active ingredients of the formula I allow disease on plants or parts of plants (fruit, flowers, foliage, staLks, tubers or roots) of a range of useful crops to be contained or prevented, and even parts of plants which are formed at a later point in time remain free from, for example, phytopathogenic fungi.

The novel active ingredients of the formula I prove to be effective against specific genera from the fungal classes Fungi imperfecti (for example Cercospora), Basidiomycetes (for example Puccinia) and Ascomycetes (for example ~rysiphe and Venturia) but, in particular, against Oomycetes (for example Plasmopara, Peronospora, Pythium, Bremia and Phytophthora). They are therefore a valuable complement of the compositions used in WO 94/01411 ~1 ~ 7 fi 8 ~ PCr/EP93/0166--crop protection for controlling phytopathogenic fungi. Advantageously, they have curative as well as preventive plupelLies when used in practice, and they can be used for the protection of a large number of crop plants. Using these active ingre~ier~t.s, the pests found on plants or parts of plants (fruit, flowers, foliage, stalks, tubers or roots) of a wide range of useful crops can be cont~inPd or destroyed, and even parts of plants which are formed at a later point in time remain free from, for ex~mple, phytopathogenic fungi. The compounds of the formula I can furthermore be used as seed-dressing agents for the tre~tmP.nt of seed (fruit, tubers or grains) and plant cuttings for protecting them against fungal infection and against soil-borne phytopathogenic fungi.

The invention also relates to the compositions which comprise compounds of the formula I as active ingredient and to their use in the field of agriculture or in related fields.

Moreover, the present invention also embraces the preparation of these compo.citionc~
which compri.cPs intim~t~P.ly mixing the active ingredient with one or more substances or subst~nr,e groups described herein. The invention also embr~res a method for treating plan s, which is distinguished by applying the novel compounds of the formula I, or the novel compositionc Target crops for the use (licclosed herein for the purposes of crop protection are, within the scope of the invention, for example the following plant species: cereals (wheat, barley, rye, tritir~le, oats, rice, maize, sorghum and related species); beet (sugar beet and fodder beet); palm fruit, stone fruit and soft fruit (apples, pears, plums, peaches, almonds, cherries, strawberries, raspberries and blackberries); leguminous plants (beans, len~ils, peas, soya beans); oil crops (oilseed rape, mustard, poppy, olives, sunflowers, coconut, castor-oil plant, cacao, groundnut); cucurbits (pumpkin, cucumbers, melons); fibre plants (cotton, flax, hemp, jute); citrus fruit (oranges, lemons, grapefruit, mandarins); vegetable crops (spinach, lettuce, asparagus, cabbages, carrots, onions, tomatoes, potatoes, bell peppers); Lauraceae (avocado, cinnamon, camphor) or other crop plants such as tobacco, nuts, coffee, sugar cane, tea, pepper and other spice plants, vines, hops, Mlls~ce~e and latex plants as well as orn~mentals.

Active ingredients of the formula I are customarily used in the form of compositions and can be applied to the area or plant to be treated either simultaneously with other active ingredients or in succession. These other active ingredients can be fertilisers, trace element mediators or other preparations which affect the growth of the plants. Selective herbicides ~ro 94/01411 ~ 1 3 ~ 6 8 ~ . PCr/EP93/01660 as well as insecticides, fungicides, bactericides, nematicides, molluscicides or mixtures of several of these preparations, together with or without other carriers conventionally used in the art of formulation, surf~ct~nts or other application-enhancing additives can also be used.

Suitable carriers and additives can be solid or liquid and are those subst~nces which are expedient in the art of formulation, for e~m~le natural or regenerated mineral s~lbst~n~es, solvents, rlicpers~ntC, wetting agents, t~kifiers, thickeners, binders or fertilisers.

A preferred process for applying an active ingredient of the formula I, or an agrochP-mic~l comrricin~ at least one of these active ingredients, is application to the foliage (foliar application). Frequency and rate of application depend on the. risk of infestation with the pathogen in question. The compounds of the formula I can also be applied to seeds (coating), either by soaking the grains in a liquid preparation of the active ingredient or by coating them with a solid ~-e~n-~,tiol~

The compounds of the formula I are employed as pure active ingredients or, preferably, together with the ~nx~ riçs conventionally used in the art of formulation. To this end, they are processed advantageously in a known manner to give, for example, emulsion conce~tr~tPs, spreadable pastes, directiy sprayable or dilutable solutions, dilute emulsions, wettable powders, soluble powders, dusts, granules or encapsulations, for example in polymeric subst~nces. The methods of application such as spraying, atomicing, dusting, SC~tlPl ing, brushing on or pouring, as well as the nature of the formulation, are selected to suit the intende~ aims and the prevailing circumct~n~es Favourable rates of application are, as a rule, 5 g to 2 kg of active ingredient (A.I.) per hectare (ha), preferably 10 g to 1 kg of A.I./ha, in particular 20 g to 600 g of A.I./ha.

The formulations, i.e. the compositions, preparations or combinations compricing the active ingredient of the formula I with or without or a solid or liquid additive, are prepared in a known manner, for example by intim~tPly mixing and/or grinding the active ingredient with extenders such as solvents, solid carriers and, if appropriate, surface-active compounds (surfactants), The following are possible as solvents: aromatic hydrocarbons, preferably the fractions C8 to Cl2, such as xylene mixtures or substituted naphthalenes, phthalic esters, such as 3 i fii8 ~ PCr/EP93/0166--dibutyl phth~l~te or dioctyl phth~l~te7 aliphatic hydrocarbons, such as cyclohexane or paraffins, alcohols and glycols as well as their ethers and esters, such as ethanol, ethylene glycol, ethylene glycol monomethyl ether and ethylene glycol monoethyl ether, ketones such as cyclohexanone, strongly polar solvents such as N-methyl-2-pyrrolidone, dimethyl sulfoxide or dimethylform~midç, and epoxidised or unepoxidised vegetable oils such as epoxidised coconut oil or soya oil, as well as water.

Solid carAers which are used, as a rule, for example for dusts and ~iicper.sible powders, are ground natural minerals such as calcite, talc, kaolin, montmoAllonite or attapulgite. To improve the physical prope,lies, it is also possible to add highly-disperse silica or highly-disperse absorptive polymers. Possible particulate, adsorptive carAers for granules are porous types, such as pummice, bAck grit, sepiolite or be~torlitP., and possible non-sorptive carrier m~tPri~l~ are, for eY~mplç, calcite or sand. Moroever, a large number of pregr~n~ tPd m~tçri~lc of inorganic or organic nature can be used, such as dolomitp or co.~ uted plant re.~i(hlç.

Suitable surface-active compounds are non-ionic, c~tionic and/or anionic surf~ct~nts which have good emulsifying, dispersing and wetting prope,~es, depending on the nature of the active ingredient of the formula I to be formulated. Surfactants are also to be understood as mç~ning mixtures of surfactants.

Possible anionic sllrf~-t~nt~ can be so-called water-soluble soaps as well as water-soluble synthetic surface-active compounds.

Examples of non-ionic sl-rf~ct~nts which may be mentioned are nonylphenol polyethoxyethanols, castor oil polyglycol ethers, polypropylene oxide/polyethylene oxide adducts, tributylphenoxypolyethylene ethanol, polyethylene glycol and octylphenoxypolyethoxyethanol .

Fatty acid esters of polyoxyethylene sorbitan, such as polyoxyethylene sorbitan trioleate, are also suitable.

The cationic sllrF~ct~nt.c are, in particular, quaternary ammonium salts which comprise at least an alkyl radical having 8 to 22 carbon atoms as N-substituents and lower, halogenated or free alkyl, benzyl or lower hydroxyalkyl radicals as further substituents.

IO 94/01411 ~1 ~ 76-~8 C ` PCr/EP93/01660 Other surfactants conventionally used in the art of formulation are known to those skilled in the art or can be found in the relevant specialist literature.

As a rule, the agrochemical preparations comprise 0.1 to 99 per cent by weight, in particular 0.1 to 95 per cent by weight, of active ingredient of the formula I, 99.9 to 1 per cent by weight, in particular 99.8 to 5 per cent by weight, of a solid or liquid additive, and 0 to 25 per cent by weight, in particular 0.1 to 25 per cent by weight, of a surfactant.

While concentrated compositions are more plerelled as commercially available goods, the end consumer uses, as a rule, dilute compositionc.

The compo~ition.~ can also compri~e further additives such as .~t~bili.cers, antifoams, viscosity regulators, binders or t~ckifiPrs, as well as fertilisers or other active ingredients to achieve specific effects.

The e~r~mplçs which follow illustrate the above-described invention without restricting the scope of the latter in any way. Temperatures are given in degree centigrade.

Preparation example 1. Prepration of ~J~ ,~CN [Compound 0.3]
F3C so2N(cH3)2 1(3)-Dimethylsulfamoyl-2-cyano-4,6-bistrifluoromethylbenzimidazole 10.0 g (36 mmol) of 2-cyano-4,6-bistrifluoromethylbenzimidazole are dissolved in 100 ml of acetone, 2.6 g of potassium hydroxide (85 %, pulverulent) are added, and the mixture is stirred for 1 hour at 25C. The solution will now have turned orange. 5.8 ml of N,N-dimethylsulfamoyl chloride are slowly added dropwise. The process is slightly exothermal. The mixture is stirred for 22 hours at room temperature and then filtered, the filtrate is concentrated to dryness on a rotary evaporator, and the residue is dissolved in methylene chloride and silica gel is added. After the mixture has been stirred for 2 hours, WO 94/01411 ~1 3 7 6 8 6 PCr/EP93/01661--it is filtered, the filtrate is concentrated and digested with ether and the product is finally filtered off and dried. Yield 4.6 g. Melting point 166-168C.

2. Preparation of ~ C C~ [Compound 1.3]
F3C SO2N(CH3)2 NH2 1 (3)-Dimethylsulfamoyl-2-carbothioamido-4,6-bistrifluoromethylbenzimidazole 140 g (0.36 mol) of 1(3)-dimethylsulfamoyl-2-cyano-4,6-bistrifluoromethylbcn7imid~7O1e are dissolved in 1500 ml of dio~ne at room temperature with stirring, and 490 ml of tetrahydrofuran and then 53 ml of triethylamine are added. Into this mixture, hydrogen sulfide is passed slowly over 2 hours at room temperature. When the reaction has ended, the mixture is concentrated on a rotary evaporator to approximately half its volume, and this is subsequently poured into ice-water with stirring, and the precipitate which has separated out is filtered off with suction and washed with water. After drying the crystals melt at 212-213C with decomposition.

3. Preparation of S~
F3C J~2N(CH3)2 [Compound 2.2]

1(3)-Dimethylsulfamoyl-2-carbothioamido-4,6-bistrifluoromethylbenzimidazole S-oxide 2.0 g (5 mmol) of 1(3)-dimethylsulfamoyl-2-carbothioamido-4,6-bistrifluoromethylbenzimidazole are suspended in 30 ml of glacial acetic acid. 1.87 g of anhydrous sodium acetate are added. A
thick, yellow suspension is formed. 0.5 ml of hydrogen peroxide (30 % in water) are added slowly with vigorous stirring, and the mixture is stirred for 3 hours at 20C. The batch is subsequently poured into ice-water and filtered, and the filtrate is washed with water until 'O 94/01411 ~1~3 7 6 8 ~ . PCr/EP93/01660 neutral and dried at 50C in a drying cupboard. Yield 1.85 g (88.9 % of theory). Melting - point 162-164C.

Preparation of the intermediates a) 2-Cyano-4,6-bistrifluoromethylben7imi~7O1e 12.2 g (50 mmol) of 1,2-diarnino-3,5-bistrifluoromethylbenzene are dissolved in 50 ml of glacial acetic acid, and 13.3 g (83 mmol) of methyl 2,2,2-trichloroacet~mi~tP are subsequently added dropwise at room temperature. The batch is stirred until the adduct has disappeared. Using tetrahydro~, this reaction solution is subsequently flushed into a dropping funnel and added dropwise with ice-cooling to 290 ml of concentrated ammonia solution. After the Illi~lUl`~ has been stirred for 1 hour at 25-30C, it is con~entr~ted on a rotary evaporator, the oily residue is treated with water, and the mixture is acidified using col~ce~ ted lly~ochloric acid. The product is extracted using ethyl ~cet~t~, washed with water, dried over sodium sulfate and concentrated. The oil which remains is chromato~raphP,d on silica gel using ethyl acetate. This gives applo~i.nately 15 g of oil which is suffiriPntly pure for use in the subsequent step.

b) 1,2-Diamino-3,5-bictrifl~ romethylbellzene 13.8 g (50 mmol) of 2-nitro-4,6-bistrifluoromethylaniline are dissolved in 140 ml of tetrahydrofuran, 6 g of Raney nickel are added, and the mixture is hydrogenated under atmospheric pressure at 20-25C. When the uptake of hydrogen has ceased, the catalyst is removed by filtration, and the solvent is distilled off on a rotary evaporator. 12.2 g of product are obtained.

c) 2-Nitro~,6-bi~trifluoromethylaniline 19.6 g (58 mmol) of 2-nitro-4,6-bistrifluoromethylbromobenzene are dissolved in 70 ml of ethanol, 15 g of ammonia are injected into the autoclave, and the mixture is heated to 125C. After 6 hours, the autoclave is discharged, the reaction mixture is concentrated, stirred with water and filtered, and the solids are dried. Yield 14.8 g. Melting point 72-73C.

d) 2-Nitro-4,6-bistrifluoromethylbromobenzene 19.5 g (66 mmol) of 2,4-bistrifluoromethylbromobenzene are heated at approximately 95C. 80 ml of a mixture of concentrated sulfuric acid and fuming nitric acid (ratio 1: 1) are added dropwise with stirring. When the addition has ended, stirring is continued for WO 94/01411 2-13 7 6 ~ ~ PCI /EP93/0166 ~' 2 hours at 95-100C. When cold, the mixture is poured into ice-water, and the product is extr~ctecl using ethyl acetate and washed with water, dilute sodium hydroxide solution and saline, dried over sodium sulfate and concentrated. The oil which remains is cl~lull~alographed on silica gel using a short column and hexane. Yield 20.6 g of oil.

Here and hereinafter, the 1 (3)-dimethylsulfamoyl group can also be termed 1 (3)-dimethyl~minoslllfonyl.

Examples of other compounds which can be ~lt;p~,d in this manner or following one of the methods intlic ~t~l further above are the following.

Table 0 F3C ~S02CRN (Ia) Compound No. R2 M.p.

û. 1 CH3 199-202C
0.2 cyclopentyl 0.3 N(CH3)2 166-168C
0.4 cyclohexyl 0.5 C4H9-tert 0.6 cyclopropyl 0.7 C4Hg-sec 0.8 C4Hg-n ~ CH3 0.9 ` C2H5 120-121 C
0.10 C3H7-i 0.11 N(C2Hs)2 112-11~C
,CH3 0.12 ` C3Hri 0.13 c3H7-n 0. 14 C2H5 0 94/0141 l PCI /EP93/01660 ~137G~

Table 1 S
~ (Ib) F C lN SO2R2 Compound No. R2 M.p.

1.1 -CH3 1.2 cyclopentyl 1.3 -N(CIH3)2 212-213C (dcco,.. posilion) 1.4 cyclohexyl 1.5 -C4Hg-tert.
1.6 cyclopropyl 1.7 -C4Hg-sec.
1.8 -C4Hg-n ,CH3 1.9 -N' 2()4-205C

1. 10 -C3H7-i 1.11 -N(C2Hs~2 165-167C

1.12 -N/
~C3H7-i 1.13 -C3H7-n 1. 14 -C2H5 WO 94/01411 PCr/EP93/01661 21~7686 Table 2 Cl F3 S

F3C/~o2R2 (Ic) CompoundNo. R2 M.p.

2. 1 CH3 2.2 -N(CH3)2 162-164C
,CH3 2.3 -N 162-163C
~C2H5 2.4 -N(C2Hs)2 149-150C

2.5 -N~
~C3H7-i Fonm-l~tion examples of active in~redients of the fom~ I (% = per cent by weight) 2.1. Wettable powders a) b) c) Activeingredientfromthetables 25 % 50 % 75 %
Sodium lignin~ulfonate 5 % 5 %
Sodiumlaurylsulfate 3 % - 5 %
Sodium diisobutylnaphthalene-sulfonate - 6 % 10 %
Octylphenol polyethylene glycol ether - 2 %
(7-8 mol of ethylene oxide) Highly-disperse silica 5 ~O 10 % 10 %
Kaolin 62 % 27 %

The active ingredient is mixed thoroughly with the additives, and the ~ LulG is ~ound thoroughly in a suitable mill. This gives wettable powders which can be diluted with water to give suspensions of any desired con~entr~tion.

~0 94/01411 ~1~7~ PCr/EP93/01660 ~; .

2.2. Emulsion concenLIate Active ingredient from the tables 10 %
Octylphenol polyethylene glycol ether 3 ~O
(4-5 mol of ethylene oxide) C~lcium dodecylbenzene sulfonate 3 ~o Castor oil polyglycol ether 4 %
(35 mol of ethylene oxide) CyclohPx~non.o 34 %
Xylene mi~ture 50 %

Fmnl~ionc of any desired col-rentr~tion can be prepared by Ailuting this concentr~te with water.

2.3. Dusts a) b) Active ingredient from the tables 5 % 8 %
Talc 95 %
Kaolin - 92 %

Ready-to-use dusts are obtained by mixing the active ingredient with the carrier and grinAing the ~ ure on a suitable mill.

2.4. Extruder ~ranules Active ingredient from the tables 10 %
N-~ ignin~lllfonate 2 %
Carboxymethyl celllllose 1 %
Kaolin 87 %

The active ingredient is mixed with the additives, and the mixture is ground and moistened with water. This mixture is extruded and subsequently dried in a stream of air.

2.5. Coated gr~n~ .s Active ingredient from the tables 3 %
Polyethylene glycol (MW 200) 3 %
Kaolin 94 %
(MW = molecular weight) WO 94/01411 213 7 6 8 6 PCr/EP93/016~

In a mixer, the finely-ground active ingredient is applied uniformly to the kaolin which has been moi.~te.nPd with polyethylene glycol. In this manner, dust-free coated ~r~n~ .s are obtained.

2.6. Suspension concenllate Active ingredient from the tables 40 %
Ethylene glycol 10 %
Nonylphenol polyethylene glycol ether 6 %
(15 mol of ethylene oxide) Sodium lignin~clllfonate 10 %
Carboxymethylcell-llose 1 %
37% aqueous fo~ klphyde solution 0.2 %
Silicone oil in ~e form of a 75 %
aqueous emulsion 0.8 %
Water 32 %

The finely-ground active ingredient is mixed intim~tely with the additives. This gives a suspension concenLIale from which suspensions of any desired concentration can be plt;p~ed by dilution with water.

3. Biolo~ical examPles Example 3.1: Action a~ainst Plasmopara viticola on vines a) Residual-protective action Vine seedlings in the 4-5-leaf stage are sprayed with a spray mixture (0.02 % of active ingredient) prepared with a wettable powder of the active ingredient. After 24 hours, the treated plants are infected with a sporangia suspension of the fungus. Fungus infestation is ~ssessed after incubation for 6 days at a relative atmospheric humidity of 95-100 % and at 20C.

b) Residual-curative action Vine seedlings in the 4-5-leaf stage are infected with a sporangia suspension of the fungus.
The infected plants are incubated in a humid chamber for 24 hours at a relative atmospheric humidity of 95-100 % and at 20C and then dried and sprayed with a spray mixture (0.02 % of active ingredient) prepared witn a wettable powder of the active O 94/01411 ~1 3 7 68 6 PCI/EP93/01660 ingredient. After the spray coating has dried on, the treated plants are returned to the humid chamber. The fungus infest~tion is ~csessed 6 days after the infection.

A good to very good activity against Plasmopara viticola on vines is achieved by using the compounds of Tables 0, 1 and 2 (fungus inf~st~tion reduced to 10-0 %); active ingredients Nos. 0.3, 1.3 and 2.2, in particular, cause cnmrlPtP- su~ ssion of fungus infest~tion (residual inr~s~ on 0 to S %). In contrast, the level of Plasmopara infPst~tion of untreated, but infected control plants is lO0 %.

ExamPle 3.2: Action a~ainst Phvtophthora on tomato plants Resi~ Plut~cLi~/e action Tomato plants are grown for 3 weeks and then spMyed with a spMy ~ Lul~ (0.02 % of active ingredient) prepared with a wettable powder of the active ingredient. After 24 hours, the treated plants are infpctpd with a sporangia ~s~el~inn of the fungus. The fungus ;~lres~ on is assess~d after the jnfe,ctP~I plants have been incubated for 5 days at a relative atmosphP ic hllmitlity of 90-lO0 % and at 20C.

Coll.poul~ds from Tables 0, l and 2 exhibit a ~.u~ ble activity (fungus infest~tion less than 20 %). Tnfest~tion is prevented virtually completely (0 to 5 % infestation) using coll~po,llld Nos. 0.3, 1.3, 2.2 and others. In contrast, the level of phytophthora infestation of untreated, but infected control plants is lO0 %.

ExamPle 3.3: Action a~ainst Phytophthora on ~otato plants pceci~ 1-protective action Potato plants (age: 2-3 weeks; variety: Bintje) are grown for 3 weeks and then sprayed with a spray mixture (0.02 % of active ingredient) prepared with a wettable powder of the active ingredienL After 24 hours, the treated plants are infected with a sporangia sl~cpencion of the fungus. The fungus infest~tion is ~ssessed after the infected plant~s have been incl~b~ted for 5 days at a relative atmospheric humidity of 90-100 % and at 20C.

Compounds from Tables 0, l and 2 exhibit a suct~in~hle activity (fungus infes~tion less than 20 %). Infest~tion is prevented virtually completely (0 to 5 % infes~tion) using collJp(Jund Nos. 0.3, 1.3, 2.2 and others. In contrast, the level of phytophthora infestation of untreated, but infected cont~ol plants iS lO0 %.

WO 94/01411 ~ ~ 3 7 ~ 8 ~ PCr/EP93/0166 Example 3.4: Action against Pythium on maize and su~ar beet a) Action after soil drench The fungus is grown on sterile oat kernels and added to a soil/sand mixture. Flowerpots are filled with this infected soil, and maize or sugar beet seed is sown. Immediately after sowing, the test preparations, which have been formulated as wettable powders, are poured over the soil in the form of an aqueous snspçn~cion (20 ppm of active ingredient relative to the soil volume). The pots are then placed in a greenhouse at 20-24C for 2-3 weeks. The soil is kept evenly moist by con~t~n~ly being sprinkled with a little water.
When the test is ev~hlatP-I the emergence of maize or sugar beet plants as well as the proportion of healthy and ~ice~ced plants is detP.rminPd b) Action after seed-dressing The fungus is grown on sterile oat kernels and added to a soil/sand mixture. ~;lowerpots are filled with this infPctPd soil, and maize or sugar beet seed is sown, which has been dressed with the test prep~t~tionc fi>rmtll~tPd as a powder for seed tre~tmP~t (1000 ppm of acdve ingredient relative to the weight of the seeds). The pots together with the seeds are placed in a greenhouse at 20-24C for 2-3 weeks. The soil is kept evenly moist by con.ct~ntly being sprinklPd with a little water. When the test is ev~ tPd. the emergence of maiæ or sugar beet plants as well as the proportion of healthy and rlice~ed plants is ~lP~tern~inp~d Tre~tmP.nt with compound No. 1.3 from Table 1 results in an emergence rate of over 80 %, the plants having a healthy appearance.

Claims

WHAT IS CLAIMED IS:

1. A benzimidazolesulfonic acid derivative of the formula I

(I) in which the R2SO2 group is the 1- or 3-position and causes the formation of pure or mixed positional isomers relative to the CF3 substituents and in which the substituents are as defined below:
R1 is CN or-CS(=O)nNH2, R2 is C1-C4alkyl, C3-C6cycloalkyl or -N(R')2, in,which R' substituents are identical or different C1-C3alkyl radicals; n is 0 or 1, with the proviso that R1 CS(=O)nNH2 if R2 is dimethylamino.

2. A benzimidazolesulfonic acid derivative of the formula Ib in which the R2SO2 group is in the 1- or 3-position and causes the formation of pure or mixed positional isomers relative to the CF3 substituents, and in which the substituents are defined as follows:
R1 is-CSNH2, R2 is C1-C4alkyl, C3-C6cycloalkyl or -N(R')2, in which R' substituents are identical or different C1-C3alkyl radicals.

3. A compound as claimed in claim 1, in which R2 is C1-C2alkyl, cyclopropyl or -N(R')2, where R' is methyl or ethyl and n is O or 1.

4. A compound as claimed in claim 3, in which R2 is methyl or N(CH3)2 and n is 0 or 1.

5. A compound as claimed in claim 2, in which R2 is methyl or-N(CH3)2.

6. The compound 1(3)-dimethylaminosulfonyl-2-carbothioamido-4,6-bistrifluoro-methylbenzimidazole-S-oxide according to claim 3.

7. The compound 1(3)-dimethylaminosulfonyl-2-carbothioamido-4,6-bistrifluoro-methylbenzimidazole according to claim 3.

9. A compound according to claim 4, in which R2 is dimethylamino and n is 0 or 1.

10. A composition for controlling and preventing infestation of plants by microorganisms, which comprises applying, as active ingredient, a compound of the formula I together with a suitable carrier material.

11. A method of controlling and preventing infestation of plants by microorganisms, which comprises applying, as active ingredient, a compound of the formula I to the plants, parts of the plant or the plant substrate.

12. The use of a compound according to claim 1 as a microbicide.

13. A process for the preparation of a compound of the formula Ib according to claim 1, which comprises reacting a compound of the formula Ia with H2S in the presence of a base at temperatures from -20 to +80°C.

14. A process for the preparation of a compound of the formula Ic according to claim 1, which comprises oxidising a compound of the formula Ib with organic peroxides or with hydrogen peroxide at temperatures from -20°C to +60°C.