WO2003042198A1

WO2003042198A1 - Isothiazole derivatives

Info

Publication number: WO2003042198A1
Application number: PCT/EP2002/012255
Authority: WO
Inventors: Lutz Assmann; Yoshinori Kitagawa; Haruko Sawada; Takuma Shigyo
Original assignee: Bayer Cropscience Aktiengesellschaft
Priority date: 2001-11-15
Filing date: 2002-11-04
Publication date: 2003-05-22
Also published as: JP2003146975A

Abstract

Novel isothiazole derivatives of the formula (I) wherein R has the meanings given in the specification, a process for the preparation of the new-compounds and their use as microbicides.

Description

Isothiazole Derivatives

The present invention relates to novel isothiazole derivatives, to a process for their preparation and to their use as microbicides.

It has already been known that certain isothiazole derivatives can be employed for the control of plant pests (cf. JP-A 59 024-1993 and JP-A 277 277-1996). The fungi- cidal activity of such known compounds, however, is not always satisfactory.

There have now been found novel isothiazole derivatives of the formula

wherein

R represents phenyl, which may be substituted by 1 to 5 identical or different radicals selected from halogen, alkyl having 1 to 4 carbon atoms, alkoxy having 1 to 4 carbon atoms, alkylthio having 1 to 4 carbon atoms, alkyl- sulfonyl having 1 to 4 carbon atoms, N,N-dialkyl-sulfamoyl having 1 to 4 carbon atoms in each alkyl group, N,N-alkylene-sulfamoyl having 4 or 5 carbon atoms in the alkylene group, haloalkyl having 1 to 4 carbon atoms and

1 to 9 identical or different halogen atoms, haloalkoxy having 1 to 4 carbon atoms and 1 to 9 identical or different halogen atoms, haloalkylthio having 1 to 4 carbon atoms and 1 to 9 identical or different halogen atoms, halo- alkylsulfonyl having 1 to 4 carbon atoms and 1 to 9 identical or different halogen atoms, dialkylamino having 1 to 4 carbon atoms in each alkyl group, pyrrolidinyl, phenoxy, benzyloxy, cyano and nitro; or may also be substituted by an alkylenedioxy group having 1 or 2 carbon atoms or by a haloalkylen- dioxy group having 1 or 2 carbon atoms and 1 to 4 identical or different halogen atoms, said radicals being bonded via the oxygen atoms at two adjacent carbon atoms of the phenylring, or

R represents 5- or 6-membered, unsaturated heterocyclyl comprising 1 or 2 nitrogen, oxygen and/or sulfur atoms, which heterocyclyl group may be condensed with a benzene ring and/or may be substituted by up to 3 identical or different radicals selected from halogen, alkyl having 1 to 4 carbon atoms, alkoxy having 1 to 4 carbon atoms, alkylthio having 1 to 4 carbon atoms, dialkylamino having 1 to 4 carbon atoms in each alkyl group, haloalkyl having 1 to 4 carbon atoms and 1 to 9 identical or different halogen atoms, phenylthio (which in turn may be substituted by 1 to 3 halogen atoms), phenylsulfonyl (which in turn may be substituted by 1 to 3 halogen atoms), phenyl, benzyl and nitro, or

R represents dialkylamino having 1 to 4 carbon atoms in each alkyl group, pyrrolidinyl or piperidinyl.

Further, it has been found that the isothiazole derivatives of the formula (I) can be prepared by reacting 5-acetyl-3,4-dichloro-isothiazole of the formula

a) with aldehydes of the formula

R!-CHO (III)

wherein R¹ represents phenyl, which may be substituted by 1 to 5 identical or different radicals selected from halogen, alkyl having 1 to 4 carbon atoms, alkoxy having 1 to 4 carbon atoms, alkylthio having 1 to 4 carbon atoms, alkylsulfonyl having 1 to 4 carbon atoms, N,N-dialkyl-sulfamoyl having 1 to 4 carbon atoms in each alkyl group N,N-alkylene-sulfamoyl having 4 or 5 carbon atoms in the alkylene group, haloalkyl having 1 to 4 carbon atoms and 1 to 9 identical or different halogen atoms, haloalkoxy having 1 to 4 carbon atoms and 1 to 9 identical or different halogen atoms, haloalkylthio having 1 to 4 carbon atoms and 1 to 9 identical or different halogen atoms, haloalkyl- sulfonyl having 1 to 4 carbon atoms and 1 to 9 identical or different halogen atoms, dialkylamino having 1 to 4 carbon atoms in each alkyl group, pyrrolidinyl, phenoxy, benzyloxy, cyano and nitro; or may be substituted by an alkylenedioxy group having 1 or 2 carbon atoms or by a haloalkylendioxy group having 1 or 2 carbon atoms and 1 to 4 identical or different halogen atoms, said radicals being bonded via the oxygen atoms at two adjacent carbon atoms of the phenylring, or

R¹ represents 5- or 6-membered, unsaturated heterocyclyl comprising 1 or 2 nitrogen, oxygen and/or sulfur atoms, which heterocyclyl group may be condensed with a benzene ring and/or may be substituted by up to 3 identical or different radicals selected from halogen, alkyl having 1 to 4 carbon atoms, alkoxy having 1 to 4 carbon atoms, alkylthio having 1 to 4 carbon atoms, dialkylamino having 1 to 4 carbon atoms in each alkyl group, haloalkyl having 1 to 4 carbon atoms and 1 to 9 identical or different halogen atoms, phenylthio (which in turn may be substituted by 1 to 3 halogen atoms), phenylsulfonyl (which in turn may be substituted by 1 to 3 halogen atoms), phenyl, benzyl and nitro,

in the presence of an inert diluent and, if appropriate, in the presence of an acid- binding agent or in the presence of an acid catalyst, or

b) with acetals of the formula

-OR³

R— CH^' (IN)

^{^}OR³ wherein

R² represents dialkylamino having 1 to 4 carbon atoms in each alkyl group, pyrrolidinyl or piperidinyl and

R³ represents alkyl having 1 to 4 carbon atoms,

in the presence of an inert diluent and, if appropriate, in the presence of an acid catalyst.

Finally, it has been found that the isothiazole derivatives of the formula (I) are outstandingly active as microbicides in agriculture and horticulture, particularly as fungicides for the direct control of plant diseases or for causing resistance in plants against plant pathogens.

Surprisingly, the isothiazole derivatives of the formula (I) according to the invention have a much better microbicidal activity than the already known compounds, which are structurally most similar and have the same type of action.

In the present context, the above mentioned definitions may have the following meanings:

"Halogen" and halogen in "haloalkyl", "haloalkoxy", "haloalkylthio", "haloalkylsulfonyl" and "haloalkylenedioxy" represents fluoro, chloro, bromo or iodo and preferably is fluoro, chloro or bromo.

"Alkyl" can be straight chained or branched and there may be mentioned, for example, methyl, ethyl, n- or iso-propyl, n-, iso-, sec- or tert-butyl.

"Alkoxy" can be straight chained or branched and there may be mentioned, for example, methoxy, ethoxy, propoxy, isopropoxy, n-, iso-, sec- or tert-butoxy.

"Alkylthio" can be straight chained or branched and there may be mentioned, for example, methylthio, ethylthio, n- or iso-propylthio, n-, iso-, sec- or tert-butylthio.

"Alkylsulfonyl" is an alkyl-SO₂ group, whose alkyl part can be straight chained or branched, and there may be mentioned, for example, methylsulfonyl, ethylsulfonyl, n- or isopropylsulfonyl, n-, iso-, sec- or tert-butylsulfonyl.

"Dialkylamino" denotes a group having 1 to 4 carbon atoms in each alkyl group. As examples there may be mentioned dimethylamino, diethylamino, methylethylamino, methyl-n-propylamino, methyl-isopropylamino, dipropylamino, di-(n-butyl)amino etc.

As examples of "alkylenedioxy" there may be mentioned methylenedioxy and ethylenedioxy.

"N,N-dialkyl-sulfamoyl" denotes a group having 1 to 4 carbon atoms in each alkyl group. As examples of such radicals there may be mentioned N,N-dimethyl- sulfamoyl, N,N-diethylsulfamoyl, N,N-di-n-propylsulfamoyl, N,N-di-(n-butyl)- sulfamoyl etc.

As examples of "N,N-alkylene-sulfamoyl" there may be mentioned pyrrolidino- sulfonyl and piperidino-sulfonyl. "Haloalkyl" represents straight-chained or branched alkyl having 1 to 4 carbon atoms and 1 to 9 fluorine, chlorine and/or bromine atoms. As examples there may be mentioned difluoromethyl, trifluoromethyl, chlorodifluoromethyl, 2-fluoroethyl, 2- chloroethyl, 2,2,2-trifluoroethyl, 1,1,2,2-tetrafluoroethyl, 1,1,2,2,2-pentafluoroethyl,

2-chloro-l,l,2-trifluoroethyl, 3-fluoropropyl, 3-chloropropyl, 2,2,3,3,3-pentafluoro- propyl, 1, 2,2,3,3, 3-hexafluoropropyl, perfluorobutyl etc.

"Haloalkoxy" represents a straight chained or branched group having 1 to 4 carbon atoms and 1 to 9 fluorine, chlorine and/or bromine atoms. As examples there may be mentioned difluoromethoxy, chlorodifluoromethoxy, trifluoromethoxy, 2-fluoro- ethoxy, 2-chloroethoxy, 2-bromoethoxy, 2,2,2-trifluoroethoxy, 3-chloropropoxy etc.

"Haloalkylthio" represents a straight-chained or branched group having 1 to 4 carbon atoms and 1 to 9 fluorine, chlorine and/or bromine atoms. As examples there may be mentioned difluoromethylthio, trifluoromethylthio, 2-fluoroethylthio, 2-chloro- ethylthio, 2-bromoethylthio, 2,2,2-trifluoroethylthio, 3-chloropropylthio etc.

"Haloalkylsulfonyl" is a group having 1 to 4 carbon atoms and 1 to 9 fluorine, chlorine and or bromine atoms. As examples there may be mentioned difluoro- methylsulfonyl, trifluoromethylsulfonyl, 2-fluoroethylsulfonyl, 2-chloroethyl- sulfonyl, 2-bromoethylsulfonyl, 2,2,2-trifluoroethylsulfonyl, 3-chloropropylsulfonyl etc.

As examples of "haloalkylenedioxy" there may be mentioned difluoromethylene- dioxy and tetrafluoroethylenedioxy.

Formula (I) provides a general definition of the isothiazole derivatives according to the invention. Preferred compounds of the formula (I) are those, in which R represents phenyl, which may be substituted by 1 to 5 identical or different radicals selected from fluoro, chloro, bromo, methyl, ethyl, n-propyl, isopropyl, tert-butyl, methoxy, ethoxy, isopropoxy, methylthio, ethylthio, methylsulfonyl, ethylsulfonyl, N,N-dimethylsulfamoyl, N,N-diethyl- sulfamoyl, pyrrolidinosulfonyl, piperidino-sulfonyl, trifluoromethyl, di- fluoromethoxy, trifluoromethoxy, trifluoromethylthio, trifluoromethyl- sulfonyl, 1,1,2,3,3,3-hexafluoropropylsulfonyl, di ethylamino, diethylamino, pyrrolidinyl, phenoxy, benzyloxy, cyano and nitro, and may also be substituted by a radical selected from methylenedioxy, ethylenedioxy, difluoromethylenedioxy and tetrafluoroethylenedioxy, or

R represents an unsaturated, 5- or 6-membered heterocyclic group comprising 1 or 2 heteroatoms selected from nitrogen, oxygen and sulfur, the heterocyclic group being optionally condensed with a benzene ring and being optionally substituted by 1 or 3 radicals selected from fluoro, chloro, bromo, methyl, ethyl, methoxy, methylthio, ethylthio, trifluoromethyl, dimethylamino, phenylthio which may be chloro-substituted, chloro-substituted phenyl- sulfonyl, phenyl, benzyl and nitro, or

R represents dimethylamino, diethylamino, diisopropylamino, di(n-propyl)- amino, di(n-butyl)-amino, pyrrolidinyl and piperidinyl.

Particularly preferred are those isothiazole derivatives of the formula (V), wherein

R represents phenyl, which may be substituted by 1 to 5 identical or different radicals selected from fluoro, chloro, bromo, methyl, ethyl, n-propyl, isopropyl, tert-butyl, methoxy, ethoxy, isopropoxy, methylthio, ethylthio, methylsulfonyl, ethylsulfonyl, N,N-dimethylsulfamoyl, N,N-diethylsulfamoyl, pyrrolidinosulfonyl, piperidino-sulfonyl, trifluoromethyl, difluoromethoxy, trifluoromethoxy, trifluoromethylthio, trifluoromethylsulfonyl, 1,1,2,3,3,3- hexafluoropropylsulfonyl, dimethylamino, diethylamino, pyrrolidinyl, phen- oxy, benzyloxy, cyano and nitro, and may also be substituted by a radical selected from methylenedioxy, ethylenedioxy, difluoromethylenedioxy and tetrafluoroethylenedioxy, or

R represents a heterocyclic group selected from pyrrolyl, furanyl, thienyl, pyrazolyl, imidazolyl, thiazolyl, pyridinyl, indolyl, benzofuranyl, benzo- thienyl and quinolinyl, which heterocyclic groups may be substituted by 1 to 3 radicals selected from fluoro, chloro, bromo, methyl, ethyl, methoxy, methylthio, ethylthio, trifluoromethyl, dimethylamino, phenylthio which may be chloro-substituted, chlorosubstituted phenylsulfonyl, phenyl, benzyl and nitro, or

If 5-acetyl-3,4-dichloro-isothiazole and benzaldehyde are used as starting materials, process variant (a) according to the invention can be illustrated by the following formula scheme.

If 5-acetyl-3,4-dichloro-isothiazole and N,N-dimethylformamide dimethylacetal are used as starting materials, process variant (b) according to the invention can be illustrated by the following formula scheme.

The 5-acetyl-3,4-dichloro-isothiazole of the formula (II), which is required as starting material for conducting the process according to the invention, is a novel compound. It can be prepared by

c) reacting isothiazole derivatives of the formula

wherein

R⁴ represents di(Cj_₄ alkoxycarbonyl)methyl or 2,2-dimethyl-l,3-dioxane-4,6- dion-5-yl,

with an acid in the presence of a diluent. Suitable acids for conducting process (c) are, for example, hydrochloric acid, sulfuric acid and acetic acid.

Suitable diluents for conducting process (c) are, for example, dioxane, tetrahydro- furan and dichloroethane.

Process (c) can be conducted according to the method described in Indian Journal of Chemistry, Vol. 20, page 504 (1981).

The isothiazole derivatives of the formula (V), which are required as starting materials in process (c), are novel compounds too.

The isothiazole derivatives of the formula (V) can be prepared by

d) reacting 3,4-dichloro-5-isothiazole-carbonyl chloride of the formula

with di (C_j.₄ alkyl) malonate or Meldrum's acid in the presence of an acid binder and in the presence of a diluent.

Suitable acid binders for conducting process (d) are, for example, 4-dimethyl- aminopyridine or triethylamine.

Suitable diluents for conducting process (d) are, for example, dichloromethane, tetrahydrofurane, acetonitrile or ethyl acetate. Process (d) can be conducted according to the method described in Journal of Organic Chemistry, Vol. 43, page 2087 (1978).

Formula (III) provides a general definition of the aldehydes, which are required as reaction components for carrying out process variant (a) according to the invention.

In this formula

R¹ preferably represents phenyl, which may be substituted by 1 to 5 identical or different radicals selected from fluoro, chloro, bromo, methyl, ethyl, n-propyl, isopropyl, tert-butyl, methoxy, ethoxy, isopropoxy, methylthio, ethylthio, methylsulfonyl, ethylsulfonyl, N,N-dimethylsulfamoyl, N,N-diethyl- sulfamoyl, pyrrolidinosulfonyl, piperidino-sulfonyl, trifluoromethyl, difluoro- methoxy, trifluoromethoxy, trifluoromethylthio, trifluoromethylsulfonyl, 1,1,2,3,3,3,3-hexafluoropropylsulfonyl, dimethylamino, diethylamino, pyrrol- idinyl, phenoxy, benzyloxy, cyano and nitro, and may also be substituted by a radical selected from methylenedioxy, ethylenedioxy, difluoromethylene- dioxy and tetrafluoroethylenedioxy, or

R¹ preferably represents an unsaturated, 5- or 6-membered heterocyclic group comprising 1 or 2 heteroatoms selected from nitrogen, oxygen and sulfur, the heterocyclic group being optionally condensed with a benzene ring and being optionally substituted by 1 to 3 radicals selected from fluoro, chloro, bromo, methyl, ethyl, methoxy, methylthio, ethylthio, trifluoromethyl, dimethylamino, phenylthio which may be chloro-substituted, chloro-substituted phenylsulfonyl, phenyl, benzyl and nitro.

Particularly preferred are those aldehydes of the formula (III), in which

R¹ represents phenyl, which may be substituted by 1 to 5 identical or different radicals selected from fluoro, chloro, bromo, methyl, ethyl, n-propyl, isopropyl, tert-butyl, methoxy, ethoxy, isopropoxy, methylthio, ethylthio, methylsulfonyl, ethylsulfonyl, N,N-dimethylsulfamoyl, N,N-diethyl- sulfamoyl, pyrrolidino-sulfonyl, piperidino-sulfonyl, trifluoromethyl, difluoromethoxy, trifluoromethoxy, trifluoromethylthio, trifluoromethyl- sulfonyl, 1,1,2,3,3,3-hexafluoropropylsulfonyl, dimethylamino, diethylamino, pyrrolidinyl, phenoxy, benzyloxy, cyano and nitro, and may also be substituted by a radical selected from methylenedioxy, ethylenedioxy, difluoromethylenedioxy and tetrafluoroethylenedioxy, or

R¹ represents a heterocyclic group selected from pyrrolyl, furanyl, thienyl, pyrazolyl, imidazolyl, thiazolyl, pyridinyl, indolyl, benzo furanyl, benzo- thienyl and quinolinyl, which heterocyclic groups may be substituted by 1 to 3 radicals selected from fluoro, chloro, bromo, methyl, ethyl, methoxy, methylthio, ethylthio, trifluoromethyl, dimethylamino, phenylthio which may be chloro-substituted, chloro-substituted phenylsulfonyl, phenyl, benzyl and nitro.

The following compounds may be mentioned as examples of aldehydes of the formula (III):

Benzaldehyde,

4-chlorobenzaldehyde,

4-trifluoromethylmercaptobenzaldehyde,

4-(N,N-dimethylsulfamoyl)benzaldehyde,

3-isopropoxybenzaldehyde, pyridine-4-carboaldehyde, furan-2-carboaldehyde,

1 -methylpyrrole-2-carboaldehyde, thiazole-2-carboaldehyde, quinoline-3-carboaldehyde, thiophene-2-carboaldehyde, l-methylimidazole-2-carboaldehyde, 5-chlorofuran-2-carboaldehyde, 4-trifluoromethylbenzaldehyde, 3-methoxybenzaldehyde, 4-trifluoromethoxybenzaldehyde, 2-fluorobenzaldehyde, benzofuran-2-carboaldehyde, 3-methylbenzothiophene-2-carboaldehyde, 3-methylbenzaldehyde and so on.

The aldehydes of the formula (III) are known or can be prepared according to principally known processes.

Formula (IV) provides a general definition of the acetals, which are required as reaction components for carrying out process variant (b) according to the invention. Preferred are compounds of the formula (IV), in which

R² represents dimethylamino, diethylamino, diisopropylamino, di(n-propyl)- amino, di(n-butyl, amino, pyrrolidinyl and piperidinyl and

R³ represents methyl, ethyl or n-propyl.

Particularly preferred are acetals of the formula (IV), in which

R² represents dimethylamino, diethylamino, diisopropylamino, di(n-propyl)- amino, di(n-butyl)amino,pyrrolidinyl and piperidinyl, and

R³ represents methyl or ethyl.

The following compounds may be mentioned as examples of acetals of the formula (IV): N,N-dimethylformamide dimethylacetal, N,N-dimethylformamide diethylacetal, N,N-dipropylformamide dimethylacetal, N-(dimethoxymethyl)piperidine N-(dimethoxymethyl)pyrrolidine and so on.

The acetals of the formula (IV) are known or can be prepared according to principally known processes.

Suitable diluents for conducting process variant (a) according to the invention are all customary inert organic solvents. Preferred diluents are aliphatic, alicyclic and aromatic hydrocarbons (which may optionally be chlorinated), for example, pentane, hexane, cyclohexane, petroleum ether,ligroine, benzene, toluene, xylene, dichloro- methane, chloroform, carbon tetrachloride, 1,2-dichloroethane, chlorobenzene, dichlorobenzene etc.; ethers, for example, ethyl ether, methyl ethyl ether, isopropyl ether, butyl ether, dioxane, dimethoxyethane (DME), tetrahydrofuran (THF), diethylene glycol dimethyl ether (DGM) etc.; nitriles, for example, acetonitrile, propionitrile, acrylonitrile etc.; alcohols, for example, methanol, ethanol, iso- propanol, butanol, ethylene glycol etc.; esters, for example, ethyl acetate, amyl acetate etc.; acid amides, for example, dimethylformamide (DMF), dimethyl- acetamide (DMA), N-methylpyrrolidone, 1 ,3-dimethyl-2-imidazolidinone, hexa- methylphosphoric triamide (HMPA) etc.; sulfones and sulfoxides, for example, dimethyl sulfoxide (DMSO), sulfolane etc., as well as organic bases, for example, pyridine etc.

Suitable acid-binding agents for conducting process variant (a) according to the invention are all customary inorganic and organic bases. The following bases can preferably be used:

Inorganic bases, such as hydrides, hydroxides, carbonates, bicarbonates etc. of alkali metals and alkaline earth metals, for example, sodium hydride, lithium hydride, sodium hydrogen carbonate, potassium hydrogen carbonate, sodium carbonate, potassium carbonate, lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide etc.; alkali metal amides, for example, lithium amide, sodium amide, potassium amide etc.; and organic bases such as, alcoholates, tertiary amines, dialkylaminoanilines and pyri dines, for example, triethylamine, 1,1,4,4-tetramethyl- ethylenediamine (TMEDA), N,N-dimethylaniline, N,N-diethylaniline, pyridine, 4- dimethylaminopyridine (DMAP), l,4-diazabicyclo[2,2,2]octane.

Upon carrying out process variant (a) according to the invention, the reaction temperatures can be varied within a substantially wide range. The reaction is generally carried out at a temperature between about -50°C and about +150°C, preferably between about 0°C and about +150°C.

The process variant (a) according to the invention is generally carried out under atmospheric pressure but, if desired, can also be carried out under elevated or reduced pressure.

Upon carrying out process variant (a) according to the invention, in general 1 mole of 5-acetyl-3,4-dichloro-isothiazole of the formula (II) is reacted with 1.0 to 2.0 moles of an aldehyde of the formula (III) in the presence of a diluent, such as benzene, and in the presence of an acid-binding agent such as piperidine.

Process variant (a) according to the invention can also be carried out in the absence of an acid-binding agent but in the presence of an acid catalyst. Suitable acid catalysts are Lewis acids, such as titanium tetrachloride, aluminum trichloride, boron trifluoride etc.

Upon conducting process variant (a) according to the invention in the presence of an acid catalyst, suitable diluents are inert organic solvents, such as aliphatic, alicyclic and aromatic hydrocarbons (which may optionally be chlorinated), for example, pentane, hexane, cyclohexane, petroleum ether, ligroin, benzene, toluene, xylene, di- chloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, chlorobenzene, dichlorobenzene etc.; as well as ethers, for example, ethyl ether, methyl ethyl ether, isopropyl ether, butyl ether, dioxane, dimethoxyethane (DME), tetrahydrofuran (THF), diethylene glycol dimethyl ether (DGM) etc.

Upon conducting process variant (a) according to the invention in the presence of an acid catalyst, the reaction temperatures can also be varied within a substantially wide range. The reaction is generally carried out at a temperature between about -78°C and about +100°C, preferably between about -10°C and about +50°C.

Upon conducting process variant (a) according to the invention in the presence of an acid catalyst, the reaction is also generally carried out under atmospheric pressure but, if desired can also be carried out under elevated or reduced pressure.

Upon conducting process variant (a) according to the invention in the presence of an acid catalyst, in general 1 mole of 5-acetyl-3,4-dichloro-isothiazole of the formula (II) is reacted with 1.0 to 1.5 moles of an aldehyde of the formula (III) in the presence of a diluent, such as dichloromethane, and in the presence of an acid catalyst, such as tianium tetrachloride.

Suitable diluents for carrying out process variant (b) according to the invention are all customary inert organic diluents. Preferred diluents are aliphatic, alicyclic and aromatic hydrocarbons (which may optionally be chlorinated), for example, pentane, hexane, cyclohexane, petroleum ether, ligroine, benzene, toluene, xylene, dichloro- methane, chloroform, carbon tetrachloride, 1,2-dichloroethane, chlorobenzene, dichlorobenzene etc.; ethers, for example, ethyl ether, methyl ethyl ether, isopropyl ether, butyl ether, dioxane, dimethoxyethane (DME), tetrahydrofuran (THF), diethylene glycol dimethyl ether (DGM) etc.: nitriles, for example, acetonitrile, propio- nitrile, acrylonitrile etc.; esters, for example, ethyl acetate, amyl acetate etc.; acid amides, for example, dimethylformamide (DMF), dimethylacetamide (DMA), N- methylpyrrolidone, l,3-dimethyl-2-imidazolidinone, hexamethylphosphoric triamide (HMPA) etc.; sulfones and sulfoxides for example, dimethyl sulfoxide (DMSO), sulfolane etc.; tertiary amines, for example, pyridine etc.

Suitable acid catalysts for carrying out process variant (b) according to the invention are customary strong organic acids as well as salts of tertiary amines with strong inorganic or organic acids. As examples there may be mentioned methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid etc.; amine hydrochlorides, for example, pyridine hydrochloride, triethylamine hydrochloride etc.; amine sulfonates, for example, pyridine p-toluenesulfonate, triethylamine p-toluenesulfonate etc.

Upon carrying out process variant (b) according to the invention, the reaction temperatures can also be varied within a substantially wide range. The reaction is generally carried out at a temperature between about -10°C and about +200°C, preferably between about 0°C and about +150C.

The process variant (b) according to the invention is generally carried out under atmospheric pressure but, if desired, can also be carried out under elevated or reduced pressure.

Upon carrying out process variant (b) according to the invention, in general 1 mole of

5-acetyl-3,4-dichloro-isothiazole of the formula (II) is reacted with 1.0 to 20.0 moles of an acetal of the formula (IN) in the presence of a diluent, such as dichloromethane.

The compounds according to the invention prepared by the above-mentioned processes can in each case be isolated from the reaction mixture by customary procedures and can be purified by known methods, such as crystallization, chromatography etc.

The compounds according to the present invention exhibit a strong microbicidal activity. Thus, they can be used for combating undesired microorganisms, such as phytopathogenic fungi and bacteriae, in agriculture and horticulture. The compounds are suitable for the direct control of undesired microorganisms as well as for generating resistance in plants against attack by undesired plant pathogens.

Resistance-inducing substances in the present context are to be understood as those substances which are capable of stimulating the defence system of plants such that the treated plants, when subsequently inoculated with undesirable microorganisms, display substantial resistance to these microorganisms.

Undesirable microorganisms in the present case are to be understood as phytopatho- genie fungi and bacteriae. The substances according to the invention can thus be employed to generate resistance in plants against attack by the harmful organisms mentioned within a certain period of time after the treatment. The period of time within which resistance is brought about in general extends from 1 to 10 days, preferably 1 to 7 days, after treatment of the plants with the active compounds.

Generally, the compounds according to the invention can be used as fungicides for combating phytopathogenic fungi, such as Plasmodiophoromycetes, Oomycetes, Chytridiomycetes, Zygomycetes, Ascomycetes, Basidiomycetes and Deutero- mycetes, and can also be used as bactericides for combating bacteriae, such as Pseudomonadaceae, Rhizobiaceae, Enterobacteriaceae, Corynebacteriaceae, Stre- ptomycetaceae, Proteobacteriae and Gram-positive groups.

Some pathogens causing fungal diseases which come under the generic names listed above are mentioned as examples, but not by way of limitation:

Erwinia species, such as, for example, Erwinia amylovora;

Pythium species, such as, for example, Pythium ultimum;

Phytophthora species, such as, for example, Phytophthora infestans; ^■ Pseudoperonospora species, such as, for example, Pseudoperonospora humuli or Pseudoperonospora cubensis;

Plasmopara species, such as, for example, Plasmopara viticola; Bremia species, such as, for example, Bremia Lactucae;

Peronospora species, such as, for example, Peronospora pisi or P. brassicae;

Erysiphe species, such as, for example, Erysiphe graminis;

Sphaerotheca species, such as, for example, Sphaerotheca fuliginea; Podosphaera species, such as, for example, Podosphaera leucotricha;

Nenturia species, such as, for example, Nenturi inaequalis;

Pyrenophora species, such as, for example, Pyrenophora teres or P. graminea

(conidia form: Drechslera, syn: Helminthosporium);

Cochliobolus species, such as, for example, Cochliobolus sativus (conidia form: Drechslera,syn: Helminthosporium);

Uromyces species, such as, for example, Uromyces appendiculatus;

Puccinia species, such as, for example, Puccinia recondita;

Sclerotinia species, such as, for example, Sclerotinia sclerotiorum;

Tilletia species, such as, for example, Tilletia caries; Ustilago species, such as, for example, Ustilago nuda or Ustilago avenae;

Pellicularia species, such as, for example, Pellicularia sasakii;

Pyricularia species, such as, for example, Pyricularia oryzae;

Fusarium species, such as, for example, Fusarium culmorum;

Botrytis species, such as, for example, Botrytis cinerea; Septoria species, such as, for example, Leptosphaeria nodorum;

Cercospora species, such as, for example, Cercospora canescens;

Alternaria species, such as, for example, Alternaria brassicae; and

Pseudocercosporella species, such as, for example, Pseudocercosporella herpo- trichoides.

The compounds according to the present invention are particularly suitable for causing resistance against infection of plants by plant pathogens, such as Pyricularia oryzae, Phythophthora infestans etc. The good toleration, by plants, of the active compounds, at the concentrations required for combating plants diseases, permits treatment of above-ground parts of plants, of vegetative propagation stock and seeds, and of the soil.

The compounds according to the present invention have a low toxicity against warmblooded animals and therefore can be used safely.

The active compounds can be converted into the customary formulations, such as solutions, emulsions, wettable powders, suspensions, powders, foams, pastes, granu- les, tablets, aerosols, natural and synthetic materials impregnated with active compound, very fine capsules in polymeric substances, coating compositions for use on seed, and formulations used with burning equipment, such as fumigating cartridges, fumigating cans and fumigating coils, as well as ULN cold mist and warm mist formulations.

These formulations may be produced in known manner, for example by mixing the active compounds with extenders, that is to say liquid or liquefied gaseous or solid diluents or carriers, optionally with the use of surface-active agents, that is to say emulsifying agents and/or dispersing agents and/or foam-forming agents. In the case of the use of water as an extender, organic solvents can, for example, also be used as auxiliary solvents.

As liquid solvents diluents or carriers, there are suitable in the main, aromatic hydrocarbons such as xylene, toluene or alkyl naphthalenes, chlorinated aromatic or chlorinated aliphatic hydrocarbons, such as chlorobenzenes, chloroethylenes or methylene chloride, aliphatic hydrocarbons, such as cyclohexane or paraffins, for example mineral oil fractions, alcohols, such as butanol or glycol as well as their ethers and esters, ketones, such as acetone, methyl ethyl ketone, methyl-isobutyl ketone or cyclohexanone, or strongly polar solvents, such as dimethylformamide and dimethyl-sulphoxide, as well as water. By liquefied gaseous diluents or carriers are meant liquids which would be gaseous at normal temperature and under normal pressure, for example aerosol propellants, such as halogenated hydrocarbons as well as butane, propane, nitrogen and carbon dioxide.

As solid carriers there may be used ground natural minerals, such as kaolings, clays, talc, chalk, quartz, attapulgite, montmorillonite or diatomaceous earth, and ground synthetic minerals, such as highly-dispersed silicic acid, alumina and silicates. As solid carriers for granules there may be used crushed and fractionated natural rocks such as calcite, marble, pumice, sepiolite and dolomite, as well as synthetic granules of inorganic and organic meals, and granules of organic material such as sawdust, coconut shells, maize cobs and tobacco stalks.

As emulsifying and/or foam- forming agents there may be used non-ionic and anionic emulsifiers, such as polyoxyethylene- fatty acid esters, polyoxyethylene- fatty alcohol ethers, for example alkylaryl polyglycol ethers, alkyl sulphonates, alkyl sulphates, aryl sulphonates as well as albumin hydrolysis products.

Dispersing agents include, for example, lignin sulphite waste liquors and methyl- cellulose.

Adhesives such as carboxymethylcellulose and natural and synthetic polymers in the form of powders, granules or latices, such as gum arabic, polyvinyl alcohol and poly- vinyl acetate, can be used in the formulation.

It is possible to use colorants such as inorganic pigments, for example iron oxide, titanium oxide and Prussian Blue, and organic dyestuffs, such as alizarin dyestuffs, azo dyestuffs or metal phthalocyanine dyestuffs, and trace nutrients, such as salts of iron, manganese, boron, copper, cobalt, molybdenum and zinc. The formulations in general contain from 0.1 to 95 per cent by weight of active compound, preferably from 0.5 to 90 per cent by weight.

The active compounds according to the invention can be present in the formulations or in the various use forms as a mixture with other known active compounds, such as fungicides, bactericides, insecticides, acaricides, nematicides, herbicides, bird repellents, growth factors, plant nutrients and agents for improving soil structure.

In many cases, synergistic effects are achieved, i.e. the activity of the mixture exceeds the activity of the individual components.

Examples of co-components in mixtures are the following compounds:

Fungicides: aldimorph, ampropylfos, ampropylfos potassium, andoprim, anilazine, azaconazole, azoxystrobin, benalaxyl, benodanil, benomyl, benzamacril, benzamacril-isobutyl, bialaphos, binapacryl, biphenyl, bitertanol, blasticidin-S, bromuconazole, bupirimate, buthiobate, calcium polysulphide, capsimycin, captafol, captan, carbendazim, carboxin, carvon, quinomethionate, chlobenthiazone, chlorfenazole, chloroneb, chloropicrin, chloro- thalonil, chlozolinate, clozylacon, cufraneb, cymoxanil, cyproconazole, cyprodinil, cyprofuram, carpropamide, debacarb, dichlorophen, diclobutrazole, diclofluanid, diclomezine, dicloran, diethofencarb, difenoconazole, dimethirimol, dimethomorph, diniconazole, diniconaziole-M, dinocap, diphenylamine, dipyrithione, ditalimfos, dithianon, dodemorph, dodine, drazoxolon, edifenphos, epoxiconazole, etaconazole, ethirimol, etridiazole, famoxadon, fenapanil, fenarimol, fenbuconazole, fenfuram, fenitropan, fenpiclonil, fenpropidin, fenpropimorph, fentin acetate, fentin hydroxide, ferbam, ferimzone, fluazinam, flumetover, fluoromide, fluquinconazole, flurprimidol, flusilazole, flusulfamide, flutolanil, flutriafol, folpet, fosetyl-aluminium, fosetyl-sodium, fthalide, fuberidazole, furalaxyl, furametpyr, furcarbonil, furconazole, furconazole- cis, furmecyclox, fenhexamide, guazatine, hexachlorobenzene, hexaconazole, hymexazole, imazalil, imibenconazole, immoctadine, iminoctadine albesilate, iminoctadine triacetate, iodocarb, ipconazole, iprobenfos (IBP), iprodione, irumamycin, isopro- thiolane, isovaledione, iprovalicarb, kasugamycin, kresoxim-methyl, copper preparations, such as: copper hydroxide, copper naphthenate, copper oxychloride, copper sulphate, copper oxide, oxine-copper and Bordeaux mixture, mancopper, mancozeb, maneb, meferimzone, mepanipyrim, mepronil, metalaxyl, metconazole, methasulfocarb, methfuroxam, metiram, metomeclam, metsulfovax, mildiomycin, myclobutanil, myclozolin, nickel dimethyldithiocarbamate, nitrothal-isopropyl, nuarimol, ofurace, oxadixyl, oxamocarb, oxolinic acid, oxycarboxim, oxyfenthiin, paclobutrazole, pefurazoate, penconazole, pencycuron, phosdiphen, pimaricin, piperalin, polyoxin, polyoxorim, probenazole, prochloraz, procymidone, propamo- carb, propanosine-sodium, propiconazole, propineb, pyrazophos, pyrifenox, pyrimethanil, pyroquilon, pyroxyfur, quinconazole, quintozene (PCNB), quinoxyfen, sulphur and sulphur preparations, spiroxamine, tebuconazole, tecloftalam, tecnazene, tetcyclacis, tetraconazole, thiabendazole, thicyofen, thifluzamide, thiophanate-methyl, thiram, tioxymid, tolclofos-methyl, tolylfluanid, triadimefon, triadimenol, triazbutil, triazoxide, trichlamide, tricyclazole, tridemorph, triflumizole, triforine, triticonazole, trifloxystrobin, uniconazole, validamycin A, vinclozolin, viniconazole, zarilamide, zineb, ziram and also Dagger G,

OK-8705, OK-8801, α-( 1 , 1 -dim ethyl ethyl)-β-(2-phenoxyethyl)- 1 H- 1 ,2,4-triazole- 1 -ethanol, α-(2,4-dichlorophenyl)-β-fluoro-β-propyl-lH-l,2,4-triazole-l-ethanol, α-(2,4-dichlorophenyl)-β-methoxy-α-methyl-lH-l,2,4-triazole-l -ethanol, α-(5-methyl-l,3-dioxan-5-yl)-β-[[4-(trifluoromethyl)-phenyl]-methylene]-lH-l,2,4- triazole- 1 -ethanol,

(5RS,6RS)-6-hydroxy-2,2,7,7-tetramethyl-5-(lH-l,2,4-triazol-l-yl)-3-octanone,

(E)-α-(methoxyimino)-N-methyl-2-phenoxy-phenylacetamide,

1 -(2,4-dichlorophenyl)-2-( 1 H- 1 ,2,4-triazol- 1 -yl)-ethanone O-(phenylmethyl)-oxime, 1 -(2 -methyl- 1 -naphthalenyl)- 1 H-pyrrol-2,5 -dione, l-(3,5-dichlorophenyl)-3-(2-propenyl)-2,5-pyrrolidinedione, l-[(diiodomethyl)-sulphonyl]-4-methyl-benzene, l-[[2-(2,4-dichlorophenyl)-l,3-dioxolan-2-yl]-methyl]-lH-imidazole, l-[[2-(4-chlorophenyl)-3-phenyloxiranyl]-methyl]-lH-l,2,4-triazole, l-[l-[2-[(2,4-dichlorophenyl)-methoxy]-phenyl]-ethenyl]-lH-imidazole, l-methyl-5-nonyl-2-(phenylmethyl)-3-pyrrolidinole,

2',6'-dibromo-2-methyl-4'-trifluoromethoxy-4-trifluoro-methyl-l,3-thiazole-5- carboxanilide,

2,6-dichloro-5-(methylthio)-4-pyrimidinyl thiocyanate, 2,6-dichloro-N-(4-trifluoromethylbenzyl)-benzamide,

2,6-dichloro-N-[[4-(trifluoromethyl)-phenyl]-methyl]-benzamide,

2-(2,3,3-triiodo-2-propenyl)-2H-tetrazole,

2-[(l-methylethyl)-sulphonyl]-5-(trichloromethyl)-l,3,4-thiadiazole,

2-[[6-deoxy-4-O-(4-O-methyl-β-D-glycopyranosyl)-α-D-glucopyranosyl]-amino]-4- methoxy-lH-pyrrolo[2,3-d]pyrimidine-5-carbonitrile,

2-aminobutane,

2-bromo-2-(bromomethyl)-pentanedinitrile,

2-chloro-N-(2,3-dihydro- 1 , 1 ,3-trimethyl- lH-inden-4-yl)-3-pyridinecarboxamide,

2-chloro-N-(2,6-dimethylphenyl)-N-(isothiocyanatomethyl)-acetamide, 2-phenylphenol (OPP),

3,4-dichloro- 1 -[4-(difluoromethoxy)-phenyl]- lH-pyrrol-2,5-dione, 3,5-dichloro-N-[cyano[(l-methyl-2-propinyl)-oxy]-methyl]-benzamide,

3-( 1 , 1 -dimethylpropyl- 1 -oxo- 1 H-indene-2-carbonitrile,

3-[2-(4-chlorophenyl)-5-ethoxy-3-isoxazolidinyl]-pyridine,

4-chloro-2-cyano-N,N-dimethyl-5 -(4-methylphenyl)- 1 H-imidazole- 1 -sulphonamide, 4-methyl-tetrazolo[l ,5-a]quinazolin-5(4H)-one,

8-hydroxyquinoline sulphate,

9H-xanthene-2-[(phenylamino)-carbonyl]-9-carboxylic hydrazide, bis-(l-methylethyl)-3-methyl-4-[(3-methylbenzoyl)-oxy] 2,5-thiophenedicarboxylate, cis- 1 -(4-chlorophenyl)-2-( 1 H- 1 ,2,4-triazol- 1 -yl)-cycloheptanol, cis-4-[3-[4-(l,l-dimethylpropyl)-phenyl-2-methylpropyl]-2,6-dimethyl- mo holinehydrochloride, ethyl [(4-chlorophenyl)-azo]-cyanoacetate, potassium hydrogen carbonate, methanetetrathiol sodium salt, methyl l-(2,3-dihydro-2,2-dimethyl-lH-inden-l-yl)-lH-imidazole-5-carboxylate, methyl N-(2,6-dimethylphenyl)-N-(5-isoxazolylcarbonyl)-DL-alaninate, methyl N-(chloroacetyl)-N-(2,6-dimethylphenyl)-DL-alaninate,

N-(2,6-dimethylphenyl)-2-methoxy-N-(tetrahydro-2-oxo-3-furanyl)-acetamide,

N-(2,6-dimethylphenyl)-2-methoxy-N-(tetrahydro-2-oxo-3-thienyl)-acetamide, N-(2-chloro-4-nitrophenyl)-4-methyl-3-nitro-benzenesulphonamide,

N-(4-cyclohexylphenyl)- 1 ,4,5,6-tetrahydro-2-pyrimidineamine,

N-(4-hexylphenyl)-l,4,5,6-tetrahydro-2-pyrimidineamine,

N-(5-chloro-2-methylphenyl)-2-methoxy-N-(2-oxo-3-oxazolidinyl)-acetamide,

N-(6-methoxy)-3-pyridinyl)-cyclopropanecarboxamide, N-[2,2,2-trichloro-l-[(chloroacetyl)-amino]-ethyl]-benzamide,

N-[3-chloro-4,5-bis(2-propinyloxy)-phenyl]-N'-methoxy-methanimidamide,

N-formyl-N-hydroxy-DL-alanine-sodium salt,

O,O-diethyl [2-(dipropylamino)-2-oxoethyl]-ethylphosphoramidothioate,

O-methyl S-phenyl phenylpropylphosphoramidothioate, S-methyl l,2,3-benzothiadiazole-7-carbothioate, spiro[2H]-l-benzopyran-2, (3'H)-isobenzofuran]-3'-one, Bactericides: bronopol, dichlorophen, nitrapyrin, nickel dimethyldithiocarbamate, kasugamycin, octhilinone, furancarboxylic acid, oxytetracyclin, probenazole, streptomycin, tecloftalam, copper sulphate and other copper preparations.

Insecticides / acaricides / nematicides: abamectin, acephate, acetamiprid, acrinathrin, alanycarb, aldicarb, aldoxycarb, alpha- cypermethrin, alphamethrin, amitraz, avermectin, AZ 60541, azadirachtin, azamethiphos, azinphos A, azinphos M, azocyclotin,

Bacillus popilliae, Bacillus sphaericus, Bacillus subtilis, Bacillus thuringiensis, baculoviruses, Beauveria bassiana, Beauveria tenella, bendiocarb, benfuracarb, bensultap, benzoximate, betacyfluthrin, bifenazate, bifenthrin, bioethanomethrin, biopermethrin, BPMC, bromophos A, bufencarb, buprofezin, butathiofos, butocarboxim, butylpyridaben, cadusafos, carbaryl, carbofuran, carbophenothion, carbosulfan, cartap, chloethocarb, chlorethoxyfos, chlorfenapyr, chlorfenvinphos, chlorfluazuron, chlormephos, chlorpyrifos, chloφyrifos M, chlovaporthrin, cis-resmethrin, cispermethrin, clocythrin, cloethocarb, clofentezine, cyanophos, cycloprene, cycloprothrin, cyfluthrin, cyhalothrin, cyhexatin, cypermethrin, cyromazine, deltamethrin, demeton M, demeton S, demeton-S-methyl, diafenthiuron, diazinon, dichlorvos, diflubenzuron, dimethoat, dimethylvinphos, diofenolan, disulfoton, docusat-sodium, dofenapyn, eflusilanate, emamectin, empenthrin, endosulfan, Entomopfthora spp., esfenvalerate, ethiofencarb, ethion, ethoprophos, etofenprox, etoxazole, etrimphos, fenamiphos, fenazaquin, fenbutatin oxide, fenitrothion, fenothiocarb, fenoxacrim, fenoxycarb, fenpropathrin, fenpyrad, fenpyrithrin, fenpyroximate, fenvalerate, fipronil, fluazuron, flubrocythrinate, flucycloxuron, flucythrinate, flufenoxuron, flutenzine, fluvalinate, fonophos, fosmethilan, fosthiazate, fubfenprox, furathiocarb, granulosis viruses, halofenozide, HCH, heptenophos, hexaflumuron, hexythiazox, hydroprene, imidacloprid, isazophos, isofenphos, isoxathion, ivermectin, lambda-cyhalothrin, lufenuron, malathion, mecarbam, metaldehyde, methamidophos, Metharhizium anisopliae,

Metharhizium flavoviride, methidathion, methiocarb, methomyl, methoxyfenozide, metolcarb, metoxadiazone, mevinphos, milbemectin, monocrotophos, naled, nitenpyram, nithiazine, novaluron, nuclear polyhedrosis viruses, omethoat, oxamyl, oxydemethon M,

Paecilomyces fumosoroseus, parathion A, parathion M, permethrin, phenthoat, phorat, phosalone, phosmet, phosphamidon, phoxim, pirimicarb, pirimiphos A, pirimiphos M, profenofos, promecarb, propoxur, prothiofos, prothoat, pymetrozine, pyraclofos, pyresmethrin, pyrethrum, pyridaben, pyridathion, pyrimidifen, pyriproxyfen, quinalphos, ribavirin, salithion, sebufos, silafluofen, spinosad, sulfotep, sulprofos, tau-fluvalinate, tebufenozide, tebufenpyrad, tebupirimiphos, teflubenzuron, tefluthrin, temephos, temivinphos, terbufos, tetrachlorvinphos, theta-cypermethrin, thiamethoxam, thiapronil, thiatriphos, thiocyclam hydrogen oxalate, thiodicarb, thiofanox, thuringiensin, tralocythrin, tralomethrin, triarathene, triazamate, triazophos, triazuron, trichlophenidine, trichlorfon, triflumuron, trimethacarb, thiacloprid, vamidothion, vaniliprole, Verticillium lecanii,

YI 5302, zeta-cypermethrin, zolaprofos,

(lR-cis)-[5-(phenylmethyl)-3-furanyl]-methyl-3-[(dihydro-2-oxo-3(2H)- furanylidene)-methyl] 2,2-dimethylcyclopropanecarboxylate,

(3-phenoxyphenyl)-methyl 2,2,3,3-tetramethylcyclopropanecarboxylate,

1 -[(2-chloro-5-thiazolyl)methyl]tetrahydro-3,5-dimethyl-N-nitro- 1 ,3,5-triazine- 2(lH)-imine,

2-(2-chloro-6-fluorophenyl)-4-[4-(l,l-dimethylethyl)phenyl]-4,5-dihydro-oxazole, 2-(acetyloxy)-3-dodecyl- 1 ,4-naphthalenedione,

2-chloro-N-[[[4-(l-phenylethoxy)-phenyl]-amino]-carbonyl]-benzamide,

2-chloro-N-[[[4-(2,2-dichloro-l,l-difluoroethoxy)-phenyl]-amino]-carbonyl]- benzamide, 3-methylphenyl propylcarbamate

4-[4-(4-ethoxyphenyl)-4-methylpentyl]-l-fluoro-2-phenoxy-benzene,

4-chloro-2-(l , 1 -dimethylethyl)-5-[[2-(2,6-dimethyl-4-phenoxyphenoxy)ethyl]thio]-

3 (2H)-pyridazinone,

4-chloro-2-(2-chloro-2-methylpropyl)-5-[(6-iodo-3-pyridinyl)methoxy]-3(2H)-pyri- dazinone,

4-chloro-5-[(6-chloro-3-pyridinyl)methoxy]-2-(3,4-dichlorophenyl)-3(2H)-pyri- dazinone,

Bacillus thuringiensis strain EG-2348,

[2-benzoyl- 1 -( 1 , 1 -dimethylethyl)-hydrazinobenzoic acid, 2,2-dimethyl-3-(2,4-dichlorophenyl)-2-oxo- 1 -oxaspiro [4.5]dec-3-en-4-yl butanoate,

[3-[(6-chloro-3-pyridinyl)methyl]-2-thiazolidinylidene]-cyanamide, dihydro-2-(nitromethylene)-2H- 1 ,3-thiazine-3(4H)-carboxaldehyde, ethyl [2-[[l,6-dihydro-6-oxo-l-(phenylmethyl)-4-pyridazinyl]oxy]ethyl]-carbamate,

N-(3 ,4,4-trifluoro- 1 -oxo-3 -butenyl)-glycine, N-(4-chlorophenyl)-3-[4-(difluoromethoxy)phenyl]-4,5-dihydro-4-phenyl-lH-pyra- zole- 1 -carboxamide,

N-[(2-chloro-5-thiazolyl)methyl]-N'-methyl-N"-nitro-guanidine,

N-methyl-N'-(l -methyl-2-propenyl)- 1 ,2-hydrazinedicarbothioamide,

N-methyl-N'-2-propenyl- 1 ,2-hydrazinedicarbothioamide, O,O-diethyl [2-(dipropylamino)-2-oxoethyl]-ethylphosphoramidothioate.

The active compounds can be used as such or in the form of their formulations or the use forms prepared therefrom by further dilution, such as ready-to-use solutions, emulsions, suspensions, powders, tablets, pastes, microcapsules and granules. They are used in the customary manner, for example by watering, immersion, spraying, atomising, misting, vaporizing, injecting, forming a slurry, brushing on, dusting, scattering, dry dressing, moist dressing, wet dressing, slurry dressing or encrusting.

In the treatment of parts of plants, the active compounds concentration in the use forms can be varied within a substantial range. They are, in general, from 1 to

0.0001% by weight, preferably from 0.5 and 0.001%.

For the treatment of seed, amounts of active compound of 0.1 to 10 g, especially 1 to 5 g, are generally employed per kilogram of seed.

For the treatment of soil, active compound concentrations, at the point of action, of 0.00001 to 0.1% by weight, especially of 0.0001 to 0.02%, are generally employed.

As already mentioned above, all plants and parts of plants can be treated according to the invention. In a preferred embodiment naturally occurring plant species and plant varieties or those obtained by conventional biological breeding methods, such as crossbreeding or protoplast fusion as well as parts of such plants are treated. In an additional preferred embodiment transgenic plants and plant varieties which have been obtained by genetic engineering methods, possibly in combination with conventional methods (genetically modified organisms) and parts of such plants are treated. The term "parts" or "parts of plants" or "plant parts" is explained above.

According to the invention plants of the plant varieties commercially available or used at any particular time are very preferably treated. Plant varieties are understood to be plants with specific properties ("traits") which have been obtained both by conventional breeding, by mutagenesis or by recombinant DNA techniques. They can be varieties, biotypes or genotypes.

Depending on the species or varieties of plants, their location and growth conditions (the types of soil, climate, vegetation period and feed concerned), superadditive

("synergistic") effects can occur as a result of the treatment according to the invention. Effects such as for example reduced application rates and/or broadening of the activity spectra and/or increased activity of the compounds and compositions usable according to the invention, improved plant growth, increased tolerance of high or low temperatures, increased tolerance of dry conditions or water or ground salt contents, increased flowering capacity, facilitated harvesting, acceleration of maturity, increased crop yields, higher quality and/or increased nutritional value of the harvested crops and increased storing quality and/or processibility of the harvested crops are possible, which are greater than those actually expected.

Preferred transgenic plants or plant varieties (obtained by genetic engineering) to be treated according to the invention include all plants which as a result of the genetic modification concerned have received genetic material which provides them with particularly advantageous valuable properties ("traits"). Examples of such properties are improved plant growth, increased tolerance of high or low temperatures, increased tolerance of dry conditions or water or ground salt contents, increased flowering capacity, facilitated harvesting, acceleration of maturity, increased crop yields, higher quality and/or increased nutritional value of the harvested crops and increased storing quality and/or processibility of the harvested crops. Additional and particularly noteworthy examples of such properties are increased resistance of the plants to animal and microbial pests, such as to insects, mites, phytopathogenic fungi, bacteria and/or viruses as well as increased tolerance by the plants of certain herbicidal active compounds. Examples which may be mentioned of transgenic plants are the important crop plants such as cereals (wheat and rice), corn, soybeans, potatoes, cotton, rape and fruit plants (producing apples, pears, citrus fruits and grapes), the crop plants corn, soybeans, potatoes, cotton and rape being particularly noteworthy. Particularly significant properties ("traits") are increased resistance of the plants to insects due to the toxins forming in the plants, and in particular those which are produced in the plants (hereinafter referred to as "Bt plants") by the genetic material obtained from Bacillus Thuringiensis (e.g. by the genes CrylA(a), CrylA(b), CrylA(c), CryllA, CryIIIB2, Cry9c Cry2Ab, Cry3Bb and CrylF and combinations thereof). Particularly significant properties ("traits") are the increased resistance of plants to fungi, bacteria and viruses due to systemically acquired resistance (SAR), systemin, phytoalexins, elicitors and resistance genes and correspondingly expressed proteins and toxins. Particulary significant properties ("traits") are also increased tolerance by the plants of certain herbicidal active compounds, such as for example imidazolinones, sulphonylureas, glyphosate or phosphinotricine (e.g. the "PAT" gene). The corresponding genes imparting the required properties ("traits") can also occur in the transgenic plants in combination with each other. Examples which may be mentioned of "Bt plants" are varieties of corn, cotton, soybeans and potatoes which are sold under the trade names YIELD GARD® (e.g. corn, cotton, soybeans), KnockOut® (e.g. corn), StarLink® (e.g. corn), Bollgard® (cotton), Nucotn® (cotton) and NewLeaf® (potatoes). Examples which may be mentioned of herbicide-tolerant plants are varieties of corn, cotton and soybeans which are sold under the trade names Roundup Ready® (tolerance of glyphosate, e.g. corn, cotton, soybeans), Liberty Link® (tolerance of phosphinotricine, e.g. rape), IMI® (tolerance of imidazolinones) and STS® (tolerance of sulphonylureas, e.g. com). Herbicide- resistant plants (bred for herbicide tolerance in the conventional manner) which may be mentioned are also the varieties (e.g. corn) sold under the name Clearfield®. The above statements do of course also apply to any plant varieties which may be developed in the future or launched onto the market in the future and which have the genetic properties ("traits") described above or developed in the future.

According to the invention the above-mentioned plants can be particularly advantageously treated with the compounds of the general formula I or the active compound mixtures according to the invention. The preferred ranges mentioned above for the active compounds or mixtures also apply to the treatment of these plants. Particularly advantageous is the treatment of plants with the compounds or mixtures specifically listed in the present text.

The preparation and the use of the compounds according to the invention is illustrated by the following examples. The invention, however, is not limited to said examples in any way. Preparation Examples

Synthesis Example 1

A solution of 5-acetyl-3,4-dichloroisothiazole (1.0 g), benzaldehyde (0.6 g) and piperidine (0.05 g) in benzene (10 ml) was refluxed for 8 hours. The residue obtained by concentrating the reaction solution under reduced pressure was purified by silica gel column chromatography (eluent hexane:dichloromethane = 1 :1) to obtain l-(3,4-dichloro-5-isothiazolyl)-3-phenyl-2-propen-l-one (0.9 g). mp l lO-112°C.

Synthesis Example 2

(Comp. No. 3)

To a solution of titanium tetrachloride (2.1 g) in dichloromethane (30 ml) a solution of 5-acetyl-3,4-dichloroisothiazole (2.0 g) and 3-furaldehyde (1.1 g) in dichloro- methane (10 ml) was added dropwise under ice cooling. After stirring the reaction solution at the same temperature for 5 minutes, a solution of triethylamine in dichloromethane (10 ml) was added dropwise. The mixture was stirred further for 1 hour under ice cooling. The reaction mixture was then added to ice water and, extracted with ethyl acetate. The organic phase was washed with water and dried over magnesium sulfate, and the solvent was distilled off. The remaining residue was purified by silica gel column chromatography (eluent hexane: dichloromethane = 1:1) to obtain l-(3,4-dichloro-5-isothiazolyl)-3-(3-furyl)-2-propen-l-one (0.6 g).mp 107-108°C.

Synthesis Example 3

(Comp. No. 46)

A solution of 5-acetyl-3,4-dichloroisothiazole (8.8 g), N,N-dimethylformamide di- methylacetal (50 ml) in dichloroethane (100 ml) was refluxed for 2 hours. The residue obtained by concentrating the reaction solution under reduced pressure was purified by silica gel column chromatography (eluent hexane:ethyl acetate=3:l) to obtain l-(3,4-dichloro-5-isothiazolyl)-3-(dimethylamino)-2-propen-l-one (3.7 g). mp 175-176°C.

The following Tables 1 and 2 show compounds acording to the invention, which can be synthesized according to the processes described before. The compounds of Synthesis Examples 1-3 are also listed in the Tables.

Table 1

Compound

No. R mp (°C) or n_D 20

X 105-107

// \\ 107-108 ^κo^'

13 122-123

// W

N

I CH,

Table 1 (continued)

Compound No. R mp (°C) or n_D 20

11 // w

H₃Q

14 J

Table 1 (continued)

Compound

No. R mp (°C) or n_D 20

20

^'S-^_Br

21

C₂H₅

22 // \)

O ^ CH,

23 // \\ CH,

25 // \)

26

O NO,

30

^' S NO, Table 1 (continued)

Compound

No. R mp (°C) or n_D 20

35

O cι

39

O ^NF

40

N ^XCH₃

CH, Table 1 (continued)

Compound

No. R mp (°C) or n_D 20

46 N(CH₃)₂ 175-176 47 N(C₂H₅)₂ 48 N(C₃H₇-n)₂ 49 N(C₃H₇-iso)₂ 50 N(C₄H₉-n)₂ Table 1 (continued)

Compound

No. R mp(°C)orn_D ²⁰

51

52 -<>

60 YV^CH3

N-N

^XCH₃ Table 1 (continued)

Compound

No. R mp (°C) or n_D 20

67 y \)

O ^NN(CH₃)₂

Table 2

Compound

No. (R⁵)m mp (°C) or n_D ^2ϋ

69 3-(OC₃H₇-iso)

70 4-OCH₃ 115

71 3-OCH₃ 104-106

72 2-OCH₃ 144-145

73 4-CF₃ 97

74 2-CF₃ 118-120

75 4-Cl 131-132

76 2-Cl 119-120

77 H 110-112

78 2,3-Cl₂

79 2,4-(CH₃)₂

80 2,4-Cl₂

81 2,4-F₂

82 2,5-F₂

83 2,6-F₂

84 2-Br

85 2-CH₃

86 2-CN

87 2-F

88 2-OCF₃

Table 2 (continued)

Compound

No. (R⁵)_m mp (°C) or np²⁰

89 3,4-(OCH₂O)

90 3,4-F₂

91 3,5-Cl₂

92 3,5-F₂

93 3-Br

94 3-CF₃

95 3-CH₃

96 3-C1

97 3-CN

98 3-F

100 3-OCF₃

101 4-Br

102 4-CH₃

103 4-CN

104 4-F

105 4-iso-C₃H₇

106 4-N(CH₃)₂

107 4-O(iso-C₃H₇)

108 4-OCF₃

109 4-OCHF₂

Table 2 (continued)

Compound

No. 20 ___ mp (°C) or n_D ^:

109 4-SCF₃ 110 4-SCH₃ 111 4-tert-C₄H₉ 112 2,3-(CH₃)₂, 4-OCH₃ 113 2,5-(CH₃)₂, 4-OCH₃ 114 2,3-(OCH₃)₂ 115 2,4-(OCH₃)₂ 116 2,5-(OCH₃)₂ 117 3,4-(OCH₃)₂ 118 3,5-(OCH₃)₂ 119 2-OCHF2 120 4-SC2H5 121 2,4,6-(CH₃)₃

122 4— N H

123 2,3,4,5,6-(CH₃)₅

124 4-N(C₂H₅)₂

125 2-OCH₃, 4-N(CH₃)₂

126 2,3-(OCH₂O), 4-OCH₃

127 2,4-(OCH₃)₂,3-CH₃

128 2,3,4-(OCH₃)₃

Table 2 (continued)

Compound

No. (R⁵)m mp (°C) or n_D 20

129 2,4,5(OCH₃)₃

130 ,_ }

131 3,4-(OC₂H₅)₂

132 3-OCH2"- (f y

133 3,4-(OCH₂CH₂O) 134 3-SCH₃ 135 4-SO₂C₂H₅ 136 4-SO₂N(CH₃)₂

138 3-SCF₃

139 4-SO2CF3

140 4-SO₂CF₂CHFCF₃

141 3,4-(OCF₂O)

142 3,4-(OCF₂CF₂O)

Synthesis Example 4

A mixture of 5-(3,4-dichloro-5-isothiazolecarbonyl)-2,2-dimethyl-l,3-dioxane-4,6- dione (30.2 g), concentrated hydrochloric acid (60 ml) and 1,4-dioxane (60 ml) was refluxed for 6 hours by heating. The reaction solution was added to water and the mixture was extracted with ethyl acetate (300 ml). The organic phase was dried over anhydrous magnesium sulfate and the solvent was distilled off. The remaining residue was purified by silica gel column chromatography (eluent hexane:ethyl acetate = 2:1) to obtain 5-acetyl-3,4-dichloro-isothiazole (18.3 g). mp 50-52°C

Synthesis Example 5

To a solution of 2,2-dimethyl-l,3-dioxane-4,6-dione (22.7 g) and 4-(dimethylamino)- pyridine in dichoromethane (200 ml) a solution of 3,4-dichloro-5-isothiazolecarbonyl chloride (50.5 g) in dichoromethane (50 ml) was added dropwise under ice cooling.

After addition the temperature was brought to room temperature and the mixture was stirred for further 6 hours. The reaction solution was washed with 2N aqueous hydrochloric acid and then with water. It was then dried over anhydrous magnesium sulfate and the solvent was distilled off to obtain 5-(3,4-dichloro-5-isothiazole- carbonyl)-2,2-dimethyl-l,3-dioxane-4,6-dione (30.2 g).

1H-NMR (CDC1₃, 90MHz) δ (ppm) : 1.13 (3H, singlet), 1.20 (3H, singlet),

10.50 (IH, broad singlet).

Biological Test Examples

Test Example A

Test for the effect of seed treatment against Pyricularia oryzae

Preparation of formulations of the compounds tested

Active compound: 30 - 40 parts by weight Carrier: mixture of diatomaceous earth and kaolin (1 :5), 55-65 parts by weight Emulsifier: polyoxyethylene alkyl phenyl ether, 5 parts by weight

The above-mentioned amounts of active compound, carrier and emulsifier are crushed and mixed to make a wettable powder. A portion of the wettable powder comprising the prescribed amount of active compound is diluted with water and used for testing.

Testing procedure

Seeds of paddy rice (variety: Kasabue) were drenched in a previously prepared diluted solution of an active compound having the prescribed concentration. 5 ml of such solution were used per 150 grains of seed. Drenching was conducted at a temperature of 20°C for 5 days. After the drenching, the air-dried seeds were sown in 2 plastic pots, each having a diameter of 9 cm, and the seeds were germinated by placing the pots in a warmed nursery box (32°C) for 3 days. After cultivating the seedlings for 2 weeks, the plants reached the 2 - 2.5 leaf stage. A spore suspension of artificially cultured Pyricularia oryzae was then sprayed on the test plants once, and the plants were kept at a temperature of 25°C and a relative atmospheric humidity of 100% for infection. Seven days after the inoculation, the infection rate per pot was classified and evaluated and the control value (%) was calculated. Phytotoxicity was tested at the same time.

This test is an average of the results of 2 replications.

The evaluation of the infection rate and the calculation of the control value were conducted as follows:

Infection rate Percentage of lesion area in (%)

0 0

0.5 less than 2

1 2-less than 5

2 5 -less than 10

3 10-less than 20

4 20-less than 40

5 more than 40

f _^ Infection rate of treated section x 100

Infection rate of untreated section

Test results

Compounds No. 2, 3, 4, 46, 72 and 73 showed control values of higher than 80%> at an active compound concentration of 500 ppm. No phytotoxicity was observed. Test Example B

Spraying test against Phytophthora infestans.

Testing procedure

About 1 seed of tomato (cultivar: Regina) was sown in each plastic pot of a diameter of 6 cm, and raised in a greenhouse at 15-25°C. The solution obtained by diluting the prepared formulation of the test compound to the prescribed concentration as mentioned above, was sprayed at a rate of 20 ml per 3 pots over seedlings which had reached the 4 leaf stage. Zoosporangia formed on the lesion of tomato plants, which previously had been infected with Phytophthora infestans, were washed down with a brush into distilled water to make a suspension. Five days after the tomato plants had been sprayed with the solution of active compound, the suspension was sprayed on the plants once for inoculation, and the treated plants were kept at a temperature of

20°C and a relative atmospheric humidity of 100%>. Four days after the inoculation, the infection rate per pot was classified and the control value (%) was calculated. Phytotoxicity was tested at the same time.

This test is an average of the results of 3 pots for 1 section.

Test results

Compounds No. 1 and 69 showed control values of higher than 80% at an active compound concentration of 500 ppm. No phytotoxicity was observed. Formulation Examples

Formulation Example I (Granules)

25 parts by weight of water were added to a mixture of 10 parts by weight of Compound No. 2 according to the invention, 30 parts by weight of bentonite (mont- morillonite), 58 parts by weight of talc and 2 parts by weight of lignin sulphonic acid salt, and the mixture was kneaded thoroughly. The resulting product was granulated by means of an extrusion granulator to form granules having a size of from 10 to 40 meshes. The granules were dried at a temperature between 40 and 50°C.

Formulation Example II (Granules)

95 parts by weight of a clay mineral having a particle size distribution within a range of from 0.2 to 2 mm were introduced into a rotary mixer. This product was uniformly wetted by spraying thereto under rotation a mixture of 5 parts by weight of Compound No. 46 according to the invention and a liquid diluent. The granules obtained in this manner were dried at a temperature between 40 and 50°C.

Formulation Example III (Emulsifiable Concentrate)

An emulsifiable concentrate was prepared by mixing 30 parts by weight of Compound No. 3 according to the invention, 5 parts by weight of xylene, 8 parts by weight of polyoxyethylene alkyl phenyl ether and 7 parts by weight of calcium alkylbenzene sulphonate with stirring.

Formulation Example IV (Wettable Powder)

A wettable powder was prepared by thoroughly mixing 15 parts by weight of Com- pound No. 69 according to the invention, 80 parts by weight of a mixture (1 :5) of

White Carbon (fine powder of hydrated non-crystalline silicon oxide) and powdery clay, 2 parts by weight of sodium alkylbenzene sulphonate and 3 parts by weight of a condensate of sodium alkylnaphthalene sulphonate and formaldehyde in powdery state.

Formulation Example V (Water Dispersible Granules)

20 parts by weight of Compound No. 72 according to the invention, 30 parts by weight of sodium lignin sulphonate, 15 parts by weight of bentonite and 35 parts by weight of calcined diatomaceous earth powder were thoroughly mixed with water.

The resulting product was granulated by means of extrusion through a 0.3 mm screen. After drying the product, water dispersible granules were obtained.

Claims

Patent Claims

1. Isothiazole derivatives of the formula

R represents phenyl, which may be substituted by 1 to 5 identical or different radicals selected from halogen, alkyl having 1 to 4 carbon atoms, alkoxy having 1 to 4 carbon atoms, alkylthio having 1 to 4 carbon atoms, alkylsulfonyl having 1 to 4 carbon atoms, N,N-dialkyl- sulfamoyl having 1 to 4 carbon atoms in each alkyl group, N,N- alkylene-sulfamoyl having 4 or 5 carbon atoms in the alkylene group, haloalkyl having 1 to 4 carbon atoms and 1 to 9 identical or different halogen atoms, haloalkoxy having 1 to 4 carbon atoms and 1 to 9 identical or different halogen atoms, haloalkylthio having 1 to 4 carbon atoms and 1 to 9 identical or different halogen atoms, haloalkylsulfonyl having 1 to 4 carbon atoms and 1 to 9 identical or different halogen atoms, dialkylamino having 1 to 4 carbon atoms in each alkyl group, pyrrolidinyl, phenoxy, benzyloxy, cyano and nitro; or may also be substituted by an alkylenedioxy group having 1 or 2 carbon atoms or by a haloalkylendioxy group having 1 or 2 carbon atoms and 1 to 4 identical or different halogen atoms, said radicals being bonded via the oxygen atoms at two adjacent carbon atoms of the phenylring, or

2. Isothiazole derivatives of the formula (I) according to claim 1, in which

R represents phenyl, which may be substituted by 1 to 5 identical or different radicals selected from fluoro, chloro, bromo, methyl, ethyl, n-propyl, isopropyl, tert-butyl, methoxy, ethoxy, isopropoxy, methylthio, ethylthio, methylsulfonyl, ethylsulfonyl, N,N-dimethylsulfamoyl, N,N-diethylsulfamoyl, pyrrolidino-sulfonyl, piperidino-sulfonyl, trifluoromethyl, difluoromethoxy, trifluoromethoxy, trifluoromethylthio, trifluoromethylsulfonyl, 1,1,2,3,3,3-hexafluoropropylsulfonyl, dimethylamino, diethylamino, pyrrolidinyl, phenoxy, benzyloxy, cyano and nitro, and may also be substituted by a radical selected from methylenedioxy, ethylenedioxy, difluoromefhylenedioxy and tetra- fluoroethylenedioxy, or

R represents an unsaturated, 5- or 6-membered heterocyclic group comprising 1 or 2 heteroatoms selected from nitrogen, oxygen and sulfur, the heterocyclic group being optionally condensed with a benzene ring and being optionally substituted by 1 to 3 radicals selected from fluro, chloro, bromo, methyl, ethyl, methoxy, methylthio, ethylthio, trifluoromethyl, dimethylamino, phenylthio which may be chloro-substituted, chloro-substituted phenylsulfonyl, phenyl, benzyl and nitro, or

R represents dimethylamino, diethylamino, diisopropylamino, di(n- propyl)amino, di(n-butyl)amino, pyrrolidinyl and piperidinyl.

3. Isothiazole derivatives of the formula (I) according to claim 1, in which

R represents phenyl, which may be substituted by 1 to 5 identical or different radicals selected from fluoro, chloro, bromo, methyl, ethyl, n-propyl, isopropyl, tert-butyl, methoxy, ethoxy, isopropoxy, methylthio, ethylthio, methylsulfonyl, ethylsulfonyl, N,N-dimethylsulfamoyl, N,N-diethylsulfamoyl, pyrrolidino-sulfonyl, piperidino-sulfonyl, trifluoromethyl, difluoromethoxy, trifluoromethoxy, trifluoromethylthio, trifluoromethylsulfonyl, 1,1,2,3,3 ,3-hexafluoropropylsulfonyl, dimethylamino, diethylamino, pyrrolidinyl, phenoxy, benzyloxy, cyano and niro, and may also be substituted by a radical selected from meth- ylenedioxy, ethylenedioxy, difluoromethylenedioxy and tetrafluoro- ethylenedioxy or

R represents a heterocyclic group selected from pyrrolyl, furanyl, thienyl, pyrazolyl, imidazolyl, thiazolyl, pyridinyl, indolyl, benzo- furanyl, benzothienyl and quinolinyl, which heterocyclic groups may be substituted by 1 to 3 radicals selected from fluoro, chloro, bromo, methyl, ethyl, methoxy, methylthio, ethylthio, trifluoromethyl, dimethylamino, phenylthio which may be chloro-substituted, chloro- substituted phenylsulfonyl, phenyl, benzyl and nitro, or R represents dimethylamino, diethylamino, diisopropylamino, di(n- propyl)-amino, di(n-butyl)-amino, pyrrolidinyl and piperidinyl.

4. Process for the preparation of isothiazole derivatives of the formula (II > according to claim 1, characterized in that 5-acetyl-3,4-dichloro-isothiazole of the formula

is reacted with

a) with aldehydes of the formula

R^J-CHO (III)

wherein

R¹ represents phenyl, which may be substituted by 1 to 5 identical or different radicals selected from halogen, alkyl having 1 to 4 carbon atoms, alkoxy having 1 to 4 carbon atoms, alkylthio having 1 to 4 carbon atoms, alkylsulfonyl having 1 to 4 carbon atoms, N,N-dialkyl- sulfamoyl having 1 to 4 carbon atoms in each alkyl group N,N- alkylene-sulfamoyl having 4 or 5 carbon atoms in the alkylene group, haloalkyl having 1 to 4 carbon atoms and 1 to 9 identical or different halogen atoms, haloalkoxy having 1 to 4 carbon atoms and 1 to 9 identical or different halogen atoms, haloalkylthio having 1 to 4 carbon atoms and 1 to 9 identical or different halogen atoms, haloalkylsulfonyl having 1 to 4 carbon atoms and 1 to 9 identical or different halogen atoms, dialkylamino having 1 to 4 carbon atoms in each alkyl group, pyrrolidinyl, phenoxy, benzyloxy, cyano and nitro; or may be substituted by an alkylenedioxy group having 1 or 2 carbon atoms or by a haloalkylendioxy group having 1 or 2 carbon atoms and 1 to 4 identical or different halogen atoms, said radicals being bonded via the oxygen atoms at two adjacent carbon atoms of the phenylring, or

R¹ represents 5- or 6-membered, unsaturated heterocyclyl comprising 1 or 2 nitrogen, oxygen and/or sulfur atoms, which heterocyclyl group may be condensed with a benzene ring and/or may be substituted by up to 3 identical or different radicals selected from halogen, alkyl having 1 to 4 carbon atoms, alkoxy having 1 to 4 carbon atoms, alkylthio having 1 to 4 carbon atoms, dialkylamino having 1 to 4 carbon atoms in each alkyl group, haloalkyl having 1 to 4 carbon atoms and 1 to 9 identical or different halogen atoms, phenylthio

(which in turn may be substituted by 1 to 3 halogen atoms), phenylsulfonyl (which in turn may be substituted by 1 to 3 halogen atoms), phenyl, benzyl and nitro,

in the presence of an inert diluent and, if appropriate, in the presence of an acid-binding agent or in the presence of an acid catalyst,

or

b) with acetals of the formula

-OR⁰

R— CH

(IV)

OR^J

wherein R² represents dialkylamino having 1 to 4 carbon atoms in each alkyl group, pyrrolidinyl or piperidinyl and

R³ represents alkyl having 1 to 4 carbon atoms,

5. Microbicidal compositions, characterized in that they contain at least one isothiazole derivative of the formula (I) according to claim 1 plus extenders and/or surface-active agents.

6. Process for combating undesired microorganisms, characterized in that isothiazole derivatives of the formula (I) according to claim 1 are applied to the microorganisms and/or to their habitat.

7. Use of isothiazole derivatives of the formula (I) according to claim 1 for combating undesired microorganisms.

Process for the preparation of microbicidal compositions, characterized in that isothiazole derivatives of the formula (I) according to claim 1 are mixed with extenders and/or surface active agents.