GB2035315A

GB2035315A - Azolyl ketals, process for producing them, and their use as microbicides

Info

Publication number: GB2035315A
Application number: GB7937797A
Authority: GB
Original assignee: Ciba Geigy AG
Current assignee: Novartis AG
Priority date: 1978-11-01
Filing date: 1979-10-31
Publication date: 1980-06-18
Also published as: DK461179A; DE2943631A1; ES485567A0; SE7909023L; TR20530A; GB2035315B; CA1138465A; NL7907953A; PL219356A1; IT7926996A0; FR2440367B1; PT70388A; DD152901A5; PL120450B1; AT374339B; AU535098B2; IT1124897B; BR7907069A; IL58583A0; AU5234779A

Abstract

Novel microbicidal compounds of the formula I <IMAGE> Wherein: R1 is tertbutyl or phenyl optionally substituted by halogen R2 is phenyl or diphenyl optionally substituted by 1 to 3 halogen atoms, C1-2 alkyl, methoxy, cyano, nitro, and/or phenoxy and A is <IMAGE> wherein R3 to R6 are hydrogen, C1-6 alkyl, C1-6 alkoxy methyl or phenoxy methyl or R3 and R4 together are tetramethylene and X is CH or N.

Description

SPECIFICATION Azolyl ketals, process for producing them, and their use as microbicides The present invention relates to azolyl ketals of the formula I

including salts thereof which are tolerant to plants, with inorganic or organic acids, and metal complexes, in which formula R1 is tertiary butyl, or phenyl which is unsubstituted or mono- or disubstituted by halogen, R2 is phenyl or diphenyl which in each case is unsubstituted or substituted by 1 to 3 halogen atoms, C1-C2-alkyl, methoxy, cyano, nitro and/or phenoxy, and

wherein R3, R4, R5 and R6 independently of one another are each hydrogen,C1-C6-alkyl, C-C6-alkoxymethyl or phenoxymethyl, or R3 and R4 together are tetramethylene, and X isCHorN.

By alkyl or by alkyl part of another substituent are meant, depending on the given number of carbon atoms the following groups: methyl, ethyl, propyl, butyl, pentyl or hexyl, and also isomers thereof (such as iso-propyl, iso-butyl, sec-butyl, tert-butyl, iso-pentyl, and so forth).

Halogen is fluorine, chloride, bromide or iodine.

Examples of salt-forming acids are: hydrochloric acid, hydrobromic acid, hydriodic acid, sulfuric acid, phosphoric acid, nitric acid, acetic acid, trifluoroacetic acid, trichloroacetic acid, oxalic acid, benzenesulfonic acid and methyanesulfonic acid.

Metal complexes of the formula I consist of the basic organic molecule and an inorganic or organic metal salt, for examples the halides, nitrates, sulfates, phosphates, tartrates, and so forth, of copper, manganese, iron zinc and other metals. The metal cations can be present here in the various valencies in which they occur.

The above lists containing the different examples constitute in no way any degree of limitation.

Compounds of the formula I are very valuable active substances against phytopathogenic microrganisms.

A preferred subgroup of effective fungicides is formed by those compounds of the formula I wherein R1 is tertiary butyl, or phenyl which is unsubstituted or mono- or di-substituted by fluorine or chlorine, R2 is phenyl or diphenyl which in each case is unsubstituted or substituted by 1 or 2 halogen atoms, and A is

wherein R3, R4, R5 and F6 independently of one another are each hydrogen, C1-C3-alkyl, methoxymethyl or phenoxymethyl, or F3 and R4 together are tetramethylene, and Xis CH or N.

Another subgroup of effective fungicides is formed by those compounds of the formula I wherein R1 is tertiary butyl or 2,4-dichlorophenyl, R2 is a phenyl group which is unsubstituted or substituted by methyl, chlorine, methoxy, cyano or phenoxy, and Rg and R4 together form a tetramethylene bridge.

A further subgroup of effective fungicides is formed by those compounds of the formula I wherein R1 is tertiary butyl or 2,4-dichlorophenyl, R2 is a phenyl group which is unsubstituted or substituted by methyl, chlorine, methoxy, cyano or phenoxy, and A is -CH(R3)-CH(R4)-, where F3 is hydrogen, and R4 is C1-C6-alkoxymethyl or phenoxymethyl, the C1-C3-alkoxymethyl groups being preferred among the possible alkoxymethyl side chains.

A preferred subgroup of effective fungicides consists of those compounds of the formula I wherein R1 is tertiary butyl or 2A-dichlorophenyl, R2 is a phenyl group which is mono- or disubstituted by chlorine, A forms an ethylene bridge which is unsubstituted or substituted by C1-C3-alkyl or methoxymethyl, and Xis CH or N.

Particularly preferred however are those fungicides which correspond to the formula I wherein R1 is tertiary butyl, R2 is a phenyl group which is mono- or disubstituted by chlorine, A is an ethylene bridge, and Xis CH or N.

The following individual compounds are particularly preferred: 2-tert-butyl-2-[1 -(4-chlornphenoxy)-1 -(1 ,2,4-triazol-1 -yl]-methyl-1 ,3-dioxolane, 2-tert-butyl-2-[1-(4-chlorophenoxy)-1-(imidazol-1-yl)]-methyl-1,3-dioxolane, 2-tert-butyl-2-[1 -(phenoxy)-1 -(1 ,2,4-triazol-1 -yl) ]-methyl-l 3-dioxolane, 2-tert-butyl-2-[1-(4-fluorophenoxy)-1-(1,2,4-triazol-1-yl) ]-methyl-1,3-dioxolane, 2-(2,4-dichlorophenyl)-2-[1 -(4-chlorophenoxy)-1-(1 ,2,4-triazol-1 -yl) ]-methyl-l ,3-dioxo lane, 2-tert-butyl-2-[1 -(2,4-dichlorophenoxy)-1 -(1 ,2,4-triazol-1 -yl) ]-methyl-1 ,3-dioxolane.

In accordance with further subject matter of the present invention, the compounds of the formula I are produced by reacting a compound of the formula II

with a compound of the formula III

wherein R1, R2, X and A have the meanings given under the formula I, "Hal" is halogen, preferably chlorine or bromine, and Me is hydrogen or a metal cation, preferably an alkali metal cation or alkaline-earth metal cation (for example potassium or sodium).

The process is performed optionally in the presence of aprotic polar solvents which are inert to the reactants. Examples of solvents of this type are acetonitrile, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, hexamethylphosphoric acid triamide or sulfolane.

In the cases where Me in the formula (III) is hydrogen, the process is performed in the presence of a base.

Examples of suitable bases are inorganic bases such as the oxides, hydroxides, hydrides, carbonates, and hydrogen carbonates of alkali metals and alkaline-earth metals, as well as for example tert. amines, such as triethylamine, triethylenediamine, pyridine, 4-dimethylamino-pyridine, 4-pyrrolidylpyridine and diazabicyclooctane.

The process is performed between 0 and 1 500C and under normal pressure.

The starting ketals of the formula II are produced by reacting a) acompound oftheformula IV

with a diol of the formula V HO A OH (V) in the presence of an acid; and b) halogenating the resulting ketal of the formula VI

The solvents used are solvents inert to the reactants: for example, for reaction a) hydrocarbons such as benzene, toluene and halogenated hydrocarbons (carbon tetrachloride, chloroform, methylene chloride, dichloroethane, and so forth); or for reaction b) halogenated hydrocarbons (carbon tetrachloride, chloroform, methylene chloride, and so forth), diethyl ether, tetrahydrofuran, dioxane, and the like.

Suitable acids in the case of process a) are for example mineral acids such as HBr, HCI and H2SO4, and also p-toluenesulfonic acid and boron trifluoride etherate.

Halogenating agents suitable for process b) are for example: chlorine, sulfuryl chloride, bromine or N-bromosuccinimide; and with the use of N-bromosuccinimide or chlorine, catalysts can be used (for example light, peroxide such as dibenzoyl peroxide, or a,a'-azoiso-butyronitrile).

The reaction temperatures in the case of the partial step a) are 40 to 150"C, the reaction being advantageously performed using a water separator. In the process b), the reaction temperatures are 0" to 100 C, preferably 350 to 70"C. The process steps a) and b) comprising respectively ketalising and halogenating of the pinacoline ethers IV (R1 = tert-butyl) to intermediates of the formulae VI and II constitute an independent further aspect of the present invention. This aspect is also an independent method for producing pinacoline ether ketals of the formula VI and halogenated ketals of the formula II.

The ketones on which the ketals of the formula I are based have in individual cases become known by virtue of German Offenlegungsschriften Nos. 2,325,156 and 2,705,676; German Auslegeschrift No.

2,201,063; and German Offenlegungsschrift No. 2,705,678. They cannot however be used as starting materials for the process steps described herein.

The following Examples serve to further illustrate the invention without limiting the scope thereof. The temperature values are given in degress Centigrade, and pressure values in millibars. Percentages and parts relate to weight.

PRODUCTION EXAMPLES Example 1 Production of 2-tert-butyl-2-[1-(4-chlorophenoxy)-1 -(1,2,4-triazol-l-yl)]-methyl-1,3-dioxolane of the formula

(compound No. 18) a) Production of 24ert-butyl-2-[1 -(4-chlorophenoxy)i-methyl-1 3-dioxolane of the formula

40 g of 4-chlorophenoxypinacoline and 17 g of ethylene glycol, with the addition of 0.2 g of p-toluenesulfonic acid in 300 ml of toluene, were refluxed for 30 hours using a water separator. The cooled toluene solution was washed successively with diluted bicarbonate solution and with water; it was then dried with sodium sulfate, filtered and concentrated in vacuo. The crystals obtained in this way were recrystallised from petroleum ether, and yielded 35 g of the intermediate, m.p. 68-70'.

b) Production of 24ert-butyl-2-[1 -(4-chlorophenoxy)-1 -brominej-methyl-1 3-dioxolane of the formula

24 g of 4-chlorophenoxypinacoline-ethylene ketal of step a) was dissolved in 150 ml of tetrachlor omethane, and there was slowly added dropwise at 40-50 C about 16 g of bromine. The bromine was consumed after 15 hours' stirring at this temperature. After cooling, the tetrachloromethane solution was washed with diluted bicarbonate solution, dried, and concentrated by evaporation. From petroleum ether, the residue yielded 18 g of product, m.p. 118-120'.

c) Final product 3 g of 1 ,2,4-triazole and 2 g of 55% sodium hydride suspension in paraffin oil were placed together in absolute dimethylformamide. After completion of the evolution of hydrogen, stirring was maintained for 1 hour at 80-100'. There was then added dropwise 11 g of 2-tert-butyl-2-[1 -(4-chlorophenoxy)-1 -bromine]- methyl-1,3-dioxolane in dimethylformamide, and the reaction mixture was stirred for 18 hours at 100-1209 The solvent was removed in vacuo, and the oily residue was taken up in ether, washed with water, dried, filtered, and concentrated by evaporation. There was obtained from the ether solution, after concentration, 8 g of a viscous oil, which was purified by chromatography on a silica gel column.There were obtained in this manner colourless crystals of the compound No. 18, m.p. 103-105".

Example 2 Production of 2-tert-butyl-2-[1 -(4-chlorophenoxy)-1 -(imidazol-1 -yl)]methyl-1 -1,3-dioxolane of the formula (compound No. 1)

Final product 3 g of imidazole and 2 g of 55% sodium hydride suspension in paraffin oil were placed together in absolute dimethylformamide. After completion of the evolution of hydrogen, stirring was maintained for 1 hour at 80-100 . There was then added dropwise 11 g of 2-tert-butyl-2-[1 -(4-chlorophenoxy)-1 -bromine]-methyl-1 ,3- dioxolane in dimethylformamide, and the reaction mixture was stirred for 18 hours at 100-120 . The solvent was removed in vacuo; and the oily residue was taken up in ether, washed with water, dried, filtered, and concentrated by evaporation.There was obtained from the ether solution, after concentration by evaporation, 9 g of a viscous oil, which yielded, after recrystallisation from hexane, colourless crystals of the compound No.1; m.p. 102-104'.

Example 3 Production of 2-(2,4-dichlorophenyl)-2-[1 -(4-chlorophenoxy)-1 -(1 ,2,4-triazol-1 -yl)]-methyl-1 ,3, dioxolane of the formula

(compound No.35) a) Production of 2-(2,4-dichlorophenyl)-2-[1 -(4-chlorophenoxy)]-methyl-1 3-dioxolane of the formula

A mixture of 54 g of a-(p-chlorophenoxy)-2,4-dichloroacetophenone, 20 ml of ethylene glycol and 2 g of p-toluenesulfonic acid in 400 ml of toluene was refluxed using a water separator. After a reaction time in each case of 10 hours, a further 10 ml of ethylene glycol was added.After 50 hours, the reaction mixture was cooled to room temperature, it was subsequently washed once with sodium bircarbonate solution and twice with water; the toluene phase was then separated dried over sodium sulfate, and concentrated by evaporation to thus yield 61 g of a light-yellow viscous oil.

b) Production of 2-(2,4-dichlorophenyl)-2-[1 -(4-chlorophenoxy)-1 -bromine]-methyl-1,3-dioxolane of the formula

100 g of 2-(2,4-dichlorophenyl)-2-[1/s-(4-chlorophenoxy)]-methyl-1,3-dioXolane was dissolved in 400 ml of absolute dioxane, and there was then added dropwise at 70 , with stirring, 46 g (15 ml) of bromine. After 5 hours, the reaction mixture was cooled to room temperature, and was then poured into 2 litres of ice-water, this containing 20 g of sodium bircarbonate. The oil which had precipitated was extracted with dichloromethane, the organic phase was washed with aqueous sodium bicarbonate solution, and dried over sodium sulfate. The yield was 130 g of a brown oil, which was taken up in 500 ml of hexane.There precipitated from this solution 78 g of beige-coloured crystals, m.p. 100-104".

c) Final product 37 g of 1,2,4-triazole potassium was added to a solution of 77 g of 2-(2,4-dichlorophenyl)-2-[1-(4-chloro- phenoxy)-l -bromine]-methyl-l ,3dioxolane in 500 ml of absolute dimethylformamide, and the reaction mixture was stirred for 15 hours at 100'. After removal of the dimethylformamide in vacuo, the brown residue was extracted with water and hexane/dichloromethane (8:2 parts by volume). The organic extracts were dried over sodium sulfate, and concentrated by evaporation. The yield was 62 g of a dark-brown oil, from which was obtained, after purification using an aluminium oxide (activity 2-3) column, 30 g of a yellowish crystal mass of the compound No.35, m.p. 104-107".

Example 4 Production of 2-tert-butyl-2-[1 -(2,4-dichlorophenoxy)-1 -(1 ,2,4-triazol-1-yl)j-methyl-1 ,3-dioxolane of the formula

(compound No. 26) a) Production of 2-tert-butyl-2-[1 -(2,4-dichlorophenoxy)]-methyl-1 ,3-dioxolane of the formula

50 g of 2,4-dichlorophenoxypinacoline with 20 g of ethylene glycol and 0.5 g of p-toluenesulfonic acid in 300 ml of toluene was refluxed for 24 hours using a water separator. The solution cooled to room temperature was washed with aqueous sodium bircarbonate solution and then with water; it was subsequently dried with sodium sulfate, and concentrated in vacuo to yield 55 g of colourless crystals, m.p.

61-63'.

b) Production of 2-tert-butyl-2-[1 -(2,4-dichlorophenoxy)-1 -bromine]-methyl-1 ,3-dioxolane of the formula

200 g of 2,4-dichlorophenoxypinacoline ketal produced according to a) was dissolved in 900 ml of absolute dioaxane, and there was then added dropwise at 40-50 , with stirring, 105 g of bromine, the bromine being consumed after 4 hours of stirring. Stirring was continued for 1 hour, and the reaction solution was then poured into 5 litres of ice-water containing 50 g of sodium bicarbonate. The crystals which had precipitated were filtered off with suction, dried, and recrystallised from hexane to yield 130 g of colourless crystals, m.p.

99-102'.

c) Final product 38.5 g of 2-tert-butyl-2-[1 -(2,4-dichlorophenoxy)-1 -bromine]-methyl-1 ,3-dioxolane was added to a solution of 15 g of 1 ,2,4-triazole potassium in 250 ml of dimethyl-sulfoxide, and stirring was maintained for 15 hours at 100"C. The reaction solution was then cooled to room temperature, and poured into water. The brown oil obtained was extracted with diethyl ether, dried over sodium sulfate, and purified with a silica gel column to yield 17 g of a viscous oil, which was able to be crystallised by the addition of petroleum ether. The resulting crystals of the compound No. 26 were recrystallised from hexane/diethyl ether, and had a m.p. of 106-108".

The following compounds of the formula I can be produced in an analogous manner:

TABLE I

Comp. R1 R2 R3 R4 Physical No. constants 1 t-butyl -C6H4-CI(4) H H m.p.102-104 2 t-butyl -C6H4-Cl(4) H H1/2 CuSO4 3 t-butyl -C6H4-CI(4) CH3 CH3 visc. oil 4 t-butyl -C6H4-Cl(4) H C3H7(n) 5 t-butyl -C6H4-Cl(4) H -CH2OCH3 6 t-butyl -C6H4-CI(4) -CH2-CH2-CH2-CH2 7 t-butyl -C6H3-C12(2,4) H H 8 t-butyl -C6H3-Cl2(2,4) H C2H5 9 t-butyl -C6H3-C12(2,4) H -CH2OCH3 10 t-butyl -C6H5 H H visc. oil 11 t-butyl -diphenyl H C2H5 visc. oil 12 -C6H3-C12(2,4) -C6H4-CI(4) H C3H7(n) 13 -C6H4-F(4) -C6H4-Cl(4) H H resin 14 -C6H5 -C6H3-C12(2,4) H H TABLE II

Comp. R1 R2 R5 R6 Physical No. constants 15 t-butyl -C6H4-CI(4) H H 16 -C6H3-C12(2,4) -C6H4-CI(4) CH3 CH3 m.p.82-84 C 17 -C6H4-F(4) -C6H4-Cl(4) CH3 CH3 m.p.150-151 TABLE Ill

Comp. R1 R2 R3 R4 Physical No. constants 18 t-butyl -C6H4-Cl(4) H H m.p.103-105 19 t-butyl -C6H4-CI(4) H H-1/2 CuSO4 m.p.195-198 20 t-butyl -C6H4-CI(4) H C2H5 m.p.110-115 21 t-butyl -C6H4-Cl(4) H C3H7(n) m.p. 90-92 22 t-butyl -C6H4-Cl(4) CH3 CH3 visc. oil 23 t-butyl -C6H4-Cl(4) H -CH2-O-CH3 24 t-butyl -C6H4-Cl (4) -CH2-CH2-CH2-CH2- m.p.115-120 25 t-butyl -C6H4-Cl(4) H -CH2-O-C6H5 visc. oil 26 t-butyl -C6H3-Cl2(2,4) H H m.p.106-108 27 t-butyl -C6H3-Cl2(2,4) H H-1/2Mn(NO3)2 28 t-butyl -C6H3-Cl2(2,4) H -C2H5 visc. oil 29 t-butyl -C6H3-Cl2(2,4) H -CH2-O-CH3 resin 30 t-butyl -C6H5 H H visc. oil 31 t-butyl -C6H4-F(4) H H visc. oil 32 t-butyl -diphenyl H C2H5 visc. oil 33 -C6H5 -C6H3-Cl2(2,4) H H m.p.129-132 34 -C6H4-F(4) -C6H4-Cl(4) H H m.p.115-116 35 -C6H3-Cl2(2,4) -C6H4-Cl(4) H H m.p.104-107 36 -C6H3-Cl2(2,4) -C6H3-Cl2(2,4) H H m.p.94-97 37 -C6H3-Cl2(2,4) -C6H4-Cl(4) H -CH2-O-CH3 38 -C6H3-Cl2(2,4) -C6H4-Cl(4) H C3H7(n) TABLE IV

Comp. R1 R2 F5 F6 Physical No. constants 39 t-butyl -C6H4-CI(4) CH3 CH3-HCI visc oil 40 t-butyl -C6H4-Cl(4) H H 41 -C6H3-Cl2(2,4) -C6H4-Cl(4) CH3 CH3 m.p.128-131 42 -C6H4-F(4) -C6H4-CI(4) CH3 CH3 m.p.134-138 The compounds of the formula I can be used on their own or together with suitable carriers and/or other additives. Suitable carriers and additives can be solid or liquid and they correspond to the substances common in formulation practice, such as natural or regenerated mineral substances, solvents, dispersing agents, wetting agents, adhesives, thickeners, binders or fertilisers. Active substances of the formula I may also be used in admixture with for example pesticidal preparations or preparations improving plant growth.

The content of active substance in composition capable of being sold commercially is between 0.0001 and 90%.

The compounds of the formula I can be applied in the following forms: Solidpreparations Dusts and scattering agents contain in general up to 10% of active substance. A 5% dust can consist for example of 5 parts of the active substance and 95 parts of an additive such as talcum, or of 2 parts of the active substance, 1 part of highly dispersed silicic acid and 97 parts of talcum. In addition to these, other mixtures with carriers and additives of this type and of other types customary in formulation practice are conceivable. These dusts are produced by mixing and grinding the active substances with the carriers and additives, and they can be dusted on in this form.

Granulates, such as coated granules, impregnated granules and homogeneous granules, and also pellets, usually contain 1 to 80% of active substance. Thus, a 5% granulate can for example be composed of 5 parts of the active substance, 0.25 parts of epichlorohydrin, 0.25 part of cetyl polyglycol ether, 3.50 parts of polyethylene glycol and 91 parts of kaolin (preferred particle size 0.3 - 0.8 mm). The granulates can be produced as follows: The active substance is mixed with epichlorohydrin, and the mixture is dissolved in 6 parts of acetone; the polyethylene glycol and cetyl polyglycol ether are then added. The solution thus obtained is sprayed onto kaolin, and the acetone is subsequently evaporated off in vacuo. A microgranulate of this type is advantageously used for combating soil fungi.

Liquid preparations There is generally made a distinction between active-substance concentrates which are dispersible or soluble in water and aerosols. Water-dispersible concentrates of active substance include for example wettable powders and pastes, which usually contain in the commercial packing 25 - 90% of active substance, and in ready-for-use solutuions 0.01 to 15% of active substance. Emulsion concentrates contain 10 to 50% of active substance, and solution concentrates contain in the ready-for-use solution 0.0001 to 20% of active substance. A 70% wettable power can thus consist for example of 70 parts of active substance, 5 parts of sodium dibutylnaphthyl sulfonate, 3 parts of naphthalenesulfonic acid/phenolsulfonic acid/formaldehyde condensate (in the mixture ratio of 3:2:1), 10 parts of kaolin and 12 parts of Champagne chalk.A 40% wettable powder can consist for example of the following substances: 40 parts of active substance, 5 parts of sodium lignin sulfonate, 1 part of sodium dibutyl-naphthalene sulfonate and 54 parts of silicic acid. A 25% wettable powder can be prepared in various ways. It can thus be composed for example of: 25 parts of active substance, 4.5 parts of calcium lignin sulfonate, 1.9 parts of Champagne chalk/hydroxyethyl cellulose mixture 1 1.5 parts of sodium dibutylnaphthyl sulfonate, 19.5 parts of silicic acid, 19.5 parts of Champagne chalk and 28.1 parts of kaolin.A 25% wettable powder may for example also consist of 25 parts of active substance, 2.5 parts of isooctylphenoxy-polyoxyethylene-ethanol, 1.7 parts of a Champagne chalk/ hydroxyethyl cellulose mixture 1:1,8.3 parts of sodium silicate, 16.5 parts of kieselguhr and 46 parts of kaolin. A 10% wettable powder can be produced for example from 10 parts of active substance, 3 parts of a mixture of sodium salts of saturated fatty alcohol sulfonates, 5 parts of a naphthalenesulfonic acid/ formaldehyde condensate and 82 parts of kaolin. Other wettable powders can be mixtures of 5 to 30% of active substance together with 5 parts of an absorptive carrier material such as silicic acid, 55 to 80 parts of a carrier such as kaolin and of a dispersing agent mixture consisting of 5 parts of sodium aryl sulfonate and of 5 parts of an alkylaryl-polyglycol ether. A 25% emulsion concentrate can contain for example the following emulsifiable substances: 25 parts of active substance, 2.5 parts of epoxidised vegetable oii, 10 parts of an alkylaryl sulfonate/fatty alcohol polyglycol ether mixture, 5 parts of dimethylformamide and 57.5 parts of xylene.

Emulsions of the required application concentration can be produced from concentrates of the described types by dilution with water, and these emulsions are particularly suitable for leaf application. In addition, other wettable powders having different mixture ratios or containing other carriers and additives common in formulation practice can be produced. The active substances are intimately mixed in suitable mixers with the additives mentioned, and the mixture is subsequently ground in the appropriate mills and rollers. There are obtained wettable powders which have excellent wetting and suspension properties, which can be diluted with water to give suspensions of the desired concentration, and which can be used in particular for leaf application. Compositions of this type also form subject matter of the present invention.

It has been found that compounds having the structure of the formula I surprisingly exhibit a very favourable microbicidal spectrum for practical requirements for the protectin of cultivated plants. Cultivated plants within the scope of the present invention are for example: cereals (wheat, barley, rye, oats, rice, etc.); beet: (sugar beet and fodder beet); pomaceous fruit, stone fruit and soft fruit: (apples, pears, plums, peaches, almonds, cherries, strawberries, raspberries and blackberries); legumes: (beans, lentils, peas and soya bean); oil plants: (rape, mustard, poppy, olives, sunflowers, coco, castor-oil plants, cocoa and groundnuts);Cucurbitacea: (pumpkins, cucumbers and melons); fibre plants: (cotton, flax, hemp and jute); citrus fruits: (oranges, lemons, grapefruit and mandarins); varieties of vegetables: (spinach, lettuce, asparagus, varieties of cabbage, carrots, onions, tomatoes, potatoes and paprika); or plants such as maize, tobacco, nuts coffee, tea, sugar beet, grapevines, hops, bananas and natural rubber plants, and also ornamental plants.

Fungi occurring on plants or on parts of plants (fruit, blossom, foliage, stalks, tubers or roots) of the said crops and of related cultivated crops can be inhibited or destroyed with the active substances of the formula I, and also parts of plants subsequently growing remain preserved from such fungi. The active substances are effective against the phytopathogenic fungi belonging to the following classes: Ascornycetes (for example Erysiphaceae, Fusarium, Helminthosporium, Venturia and Podosphaera); Basidiomycetes, such as in particular rust fungi (for example Puccinia, Tilletia and Hemileia); Fungi imperfecti (for example Moniliales, and so forth, Cercospora as well as Botrytis and Verticillium), and the Oomycetes belonging to the Phycomycetes class. Furthermore, the compounds of the formula I have a systemic action.They can also be used as dressing agents for treating seed (fruits, tubers and grain), and plant cuttings to protect them from fungus infections, and also against phytopathogenic fungi occurring in the soil.

The invention hence relates also to the use of the compounds of the formula I for controlling phytopathogenic microorganisms, and/or for preventing infection on plants.

BIOLOGICAL EXAMPLES Example 5: Action against Erysiphe graminis on barley a) Residual protective action Barley plants about 8 cm high were sprayed with a spray liquor produced from wettable powder of the active substance (0.02% of active substance). The treated plants were dusted after 3-4 hours with conidiospores of the fungus. The infested barley plants were kept in a greenhouse at about 22"C, and the fungus infection was assessed after 10 days.

b) Systemic action A spray liquor produced from wettable powder of the active substance (0.006% of active substance, relative to the volume of soil) was applied to the surface of the soil of barley plants about 8 cm in height. Care was taken to ensure that the spray liquor did not come into contact with the parts of the plants above the soil.

After 48 hours, the treated plants were dusted with conidiospores of the fungus. The infested barley plants were kept in a greenhouse at about 22"C, and the fungus infection was assessed after 10 days.

Example 6: Action against Puccinia graminis on wheat a) Residual protective action Six days after being sown, wheat plants were sprayed with a spray liquor prepared from wettable powder of the active substance (0.06% of active substance). After 24 hours, the treated plants were infested with a uredospore suspension of the fungus. After an incubation time of 48 hours at about 20"C with 95-100% relative humidity, the infested plants were kept in a greenhouse at about 22"C. An assessment of the development of rust pustules was made 12 days after infestation.

b) Systemic action A spray liquor produced from wettable powder of the active substance (0.006% of active substance, relative to the volume of soil) was applied to the soil of wheat plants 5 days after sowing. After 48 hours, the treated plants were infested with a uredospore suspension of the fungus. After an incubation time of 48 hours at about 20"C with 95-100% relative humidity, the infested plants were kept in a greenhouse at about 22"C. An assessment of the development of rust pustules was made 12 days after infestation.

Example 7: Action against Cercospora arachidicola on groundnut plants Residual protective action Groundnut plants 10-15 cm in height were sprayed with a spray liquor produced from wettable powder of the active substance (0.02% of active substance); and 48 hours later they we infested with a conidiospore suspension of the fungus. The infested plants were incubated for 72 hours at about 21 C with high relative humidity, and were subsequently kept in a greenhouse until the typical leaf spots had appeared. The assessment of the fungicidal action was made 12 days after infestation, and was based on the number and size of the occurring spots.

Example 8: Action against Venturia inaequalis on apple trees Residual protective action Young apple seedlings having about 5 developed leaves were sprayed with a spray liquor produced from wettable powder of the active substance (0.06% of active substance). After 24 hours, the treated plants were infested with a conidiospore suspension of the fungus. The plants were incubated for 5 days with 90-100% relative humidity, and were then kept for a further 10 days in a greenhouse at 20-24"C. The extent of scab infection was assessed 15 days after infestation.

The compounds of the formula I according to the invention exhibited in general a good fungicidal action in the tests described in the foregoing. Thus, compared with the infection on untreated but infested control plants (= 100% infection), the infection on the treated plants had been reduced to less than 20% by, among other compounds of the formula I, those compounds of the invention which are listed beiow: against Puccinia graminis: Compounds Nos. 1, 3, 11, 13, 18, 19, 20, 21, 22, 24,26,28, 29,30,31,32,34,35 and39; against Cercospora arachidicola:Compounds Nos. 1, 18, 20,22, 26,32 and 35; against Erysiphegraminis: Compounds Nos. 1,3, 11, 13,17,18, 19,20,21,22,24,25,26, 28,29,30,31,32, 33,34,35,36 and 39; and against Venturia inaequalis: Compounds 1,3, 13, 18, 19,20,21,22,25,26,28, 29,20,31,32,33,34,35, and 39.

A reduction of infection to 5% and less was produced in the above tests by the following compounds of the formula I: against Puccinia graminis: Compounds Nos. 1, 3, 13, 18, 19, 20, 22, 26, 28, 29,30, 31, 35 and 39; against Cercospora arachidicola: Compounds Nos. 1, 18, 20, 22, 26 and 35.

against Erysiphe graminis: Compounds Nos. 1, 3, 13, 18, 19, 20, 21, 22, 25,26, 28, 29,30, 31, 32,33,34,35 and 39; and against Venturia inaequalis: Compounds Nos. 1, 18,22,26,29,30,31,35 and 39.

Claims

1. Acompound of the formula I

including salts thereof which are tolerant to plants, with inorganic or organic acids, and metal complexes, in which formula F1 is tertiary butyl, or phenyl which is unsubstituted or mono- or disubstituted by halogen, R2 is phenyl or diphenyl which in each case is unsubstituted or substituted by 1 to 3 halogen atoms, C1-C2-alkyl, methoxy, cyano, nitro and/or phenoxy, and

wherein R3, R4, R5 and F6 independently of one another are each hydrogen, C1-C6-alkyl, C1-C6-alkoxymethyl or phenoxymethyl, or R3 and R4 together are tetramethylene, and X isCHorN.

2. A compound of the formula I according to Claim 1, wherein R1 is tertiary butyl, or phenyl which is unsubstituted or mono- or disubstituted by fluorine or chlorine; R2 is phenyl or diphenyl which in each case is unsubstituted or substituted by 1 or 2 halogen atoms; A is

wherein R3, R4, R5 and F6 independently of one another are each hydrogen, Ct-C3- alkyl, methoxymethyl or phenoxymethyl, or F3 and R4 together are tetramethylene; and X is CH or N.

3. A compound of the formula I according to Claim 1, wherein R1 is tertiary butyl or 2, 4-dichlorophenyl; R2 is a phenyl group which is unsubstituted or substituted by methyl, chlorine, methoxy, cyano or phenoxy; and F3 and R4 together form a tetramethylene bridge.

4. A compound of the formula I according to Claim 1, wherein R1 is tertiary butyl or 2,4-dichlorophenyl; R2 is a phenyl group which is unsubstituted or substituted by methyl, chlorine, methoxy, cyano or phenoxy; and A is -CH(R3)-CH(R4)-, where R3 is hydrogen, and R4 is C1-C6-alkoxymethyl or phenoxymethyl.

5. A compound of the formula I according to Claim 1, wherein R1 is tertiary butyl or 2,4-dichlorophenyl; R2 is a phenyl group which is mono- or disubstituted by chlorine; A forms an ethylene bridge which is unsubstituted or substituted by C1-C3-alkyl or methoxymethyl; and X is CH or N.

6. A compound of the formula I according to Claim 5, wherein R1 is tertiary butyl; R2 is a phenyl group which is mono- or disubstituted by chlorine; A is an ethylene bridge; and X is CH or N.

7. 2-tert-butyl-2-[1 -(4-chlorophenoxy)-1 -(1,2,4-triazol-1 -yl) 1-methyl-i ,3-dioxolane.

8. 2-tert-butyl-2-[i -(4-chlorophenoxy)-1 -(imidazol-i -yl)-methyl-i ,3-dioxolane.

9. 2-tert-butyl-2-[1 -(phenoxy)-l-(l ,2,4-triazol-l -yl)J-methyl-i ,3-dioxolane.

10. 2-tert-butyl-2-[1 -(4-fluorophenoxy)-l -(1 ,2,4-triazol-1 -yl) ]-methyl-l ,3-dioxolane.

11. 2-(2,4-dichlorophenyl)-2-[i -(4-ch lo rophenyl)-l -(1,2,4-triazol-1 -yl)]-methyl-i ,3-dioxolane.

12. 2-tert-butyl-2-[i -(2,4-dichlorophenoxy)-1 -(1 ,2,4-triazol-1 -yl)]-methyl-1 ,3-dioxolane.

13. A compound of the formula I according to Claim 1 substantially as described in any of Examples 1 to 4.

14. A process for producing a compound according to Claim 1, which process comprises reacting a compound oftheformula II

with a compound of the formula Ill

where R1, R2, X and A have the meanings given under the formula I, "Hal" denotes halogen, and Me is hydrogen or a metal cation.

15. A process according to Claim 14 substantially as described in any of Examples 1 to 4.

16. A compound of formula I according to Claim 1 whenever prepared by a process as claimed in Claim 14 or Claim 15.

17. A pesticidal composition for controlling phyto-pathogenic microorganisms, which composition contains as at least one active ingredient a compound of the formula I according to Claim 1, together with one or more suitable carriers.

18. A composition according to Claim 17, which contains as at least one active ingredient a compound of the formula i according to any one of Claims 1 to 13 or 16.

19. A composition according to Claim 17 substantially as described in any of Examples 5 to 8.

20. A method of combatting phytopathogenic microorganisms and/or of preventing an infection induced by such microorganisms which comprises applying to their habitat an effective amount of a compound of formula I according to Claim 1.

21. A method according to Claim 20 which comprises applying an effective amount of a compound of formula I according to any of Claims 2 to 13 or 16.

22. A method according to Claim 20 substantially as described in any of Examples 5 to 8.