GB2117772A

GB2117772A - Heterocyclic oximes

Info

Publication number: GB2117772A
Application number: GB08308866A
Authority: GB
Inventors: Franz Dorn
Original assignee: F Hoffmann La Roche AG
Current assignee: F Hoffmann La Roche AG
Priority date: 1982-03-31
Filing date: 1983-03-30
Publication date: 1983-10-19
Also published as: FR2524466A1; GB2117772B; DE3310148A1; IT8320124A0; GB8308866D0; IT1172404B

Abstract

Compounds within the general formula <IMAGE> (R<1> = optionally substituted phenyl; R<2> = optionally substituted pyridyl, pyrazinyl or pyrimidyl; R<3> = H, OH, Cl, Br, alkyl, alkenyl or alkynyl; N R<4> = substituted hydroxylimino) and their salts are fungicides.

Description

SPECIFICATION Heterocyclic compounds The invention is concerned with compounds of the general formula

wherein R1 signifies unsubstituted or mono-, di- or trisubstituted phenyl, the optionally present substituents being selected from 1 to 3 halogen atoms, 1 to 3 C1 3-alkyl groups, 1 or 2 C1 3-alkoxy groups, a trifluoromethyl group, a cyano group and a nitro group, R2 signifies 3-pyridiyl, 3-pyridlyl 1-oxide, 2-pyrazinyl, 2-pyrazinyl 1-oxide, 2-pyrazinyl 4-oxide, 2-pyrazinyl 1,4-dioxide, 5-pyrimidinyl, 5-pyrimidinyl 1-oxide, 5-pyrimidinyl 3-oxide or 5-pyrimidinyl 1 ,3-dioxide, the previously named groups being optionally substituted with methyl, methoxy or chlorine, R3 signifies hydrogen, C1 4-alkyl, C3- or C4-alkenyl, C3- or C4-alkynyl, chlorine, bromine or hydroxy, and R4 represents a group oR5 (a) or

wherein R5 is unsubstituted C1 6-alkyl or C1 6-alkyl monosubstituted with halogen, C13-alkoxy or cyano;C3-C6 cycloalkyl;C3-C6-alkenyl; C3-C6-alkynyl; unsubstituted aryl-C1.3-alkyl or aryl; or aryl-C1.3-alkyl or aryl mono-, di or trisubstituted in the aryl nucleus, the substituents being selected from 1 to 3 halogen atoms, a C1-3-alkyl group, a C1-3-alkoxy group and 1 to 3 nitro groups, R6 is unsubstituted C1.6-alkyl or C1 6-alkyl monosubstituted with halogen, C1 3-alkoxy or cyano; unsubsti tuted aryl-C1 3-alkyl or aryl-C1.3-alkyl mono-, di- ortrisubstituted in the aryl nucleus; C36-cycloalkyl; C2 6-alkenyl; unsubstituted or mono-, di or trisubstituted aryl; unsubstituted aryloxy-C1.3-alkyl or aryloxy-C1.3-alkyl mono-, di ortrisubstituted in the aryl nucleus; C16-alkoxy; C1 6-alkylamino; or di(C16-alkyl)amino, the optionally present substituents in the aryl nucleus being selected from 1 to 3 halogen atoms, a Cm 3alkyl group, a C1.3-alkoxy group and 1 to 3 nitro groups, and X signifies oxygen or sulphur, with the proviso that where simultaneously R' signifies phenyl substituted with 1 to 3 halogen atoms, R2 signifies 3-pyridyl, 3-pyridyl 1-oxide, 2-pyrazinyl, 2-pyrazinyl 1-oxide, 2-pyrazinyl 4-oxide or 2-pyrazinyl 1,4-dioxide, R3 signifies hydrogen or C1.4-alkyl, R4 signifies a group (a) and R5 signifies unsubstituted C1.6-alkyl, C3.6-cycloalkyl, C3.6-alkenyl or C3.6-alkynyl, R' can only be 3-halophenyl, 2,3-, 2,5-, 3,4- or 3,5-dihalophenyl or 2,3,4-, 2,3,5- or 2,4,5-trihalophenyl, and acid addition salts of these compounds.

The compounds of formula I and their acid addition salts have fungicidal properties and are suitable as fungicidal active substances, especially for use in agriculture and in horticulture.

The invention is also concerned with a process for the manufacture of the compounds of formula I and their acid addition salts, compounds of formula I and acid addition salts thereof as fungicidal active substances, fungicidal compositions which contain the compounds of formula I or acid addition salts thereof as the active substance as well as the use of said compounds, acid addition salts and compositions for the control of fungi in agriculture and in horticulture.

The term "halogen atom", "halogen" or "halo" in the above definition of formula I embraces fluorine, chlorine, bromine and iodine, with chlorine and bromine, especially chlorine, being preferred. When two or three halogen atoms are present as substituents on the same phenyl or aryl group, these can be the same or different.

The terms "C1 3-alkyl", "C1 4-alkyl", "Ca 6-alkyl", "C3- or C4-alkenyl", "C3 6-alkenyl", "C2 6-alkenyl", "C3- or C4-alkynyl" and "C3.6-alkynyl" embrace not only straight-chain but also branched-chain hydrocarbon groups. Under "alkyl" there are to be understood, depending on the number of carbon atoms, for example the following groups: methyl, ethyl, n-propyl, isopropyl, n-butyl, tert.butyl, isoamyl and n-hexyl.This also applies to groups containing alkyl groups such as "C1.3-alkoxy", "C1.6-alkoxy", "aryl-C13-alkyl", "aryloxy C1.3-alkyl", "C16-alkylamino" and "di(C1.6-alkyl)amino". In the last-mentioned group the Cos 6alkyl groups can be the same or different.

When R3 signifies C3- or C4-alkenyl this is preferably allyl and when R3 signifies C3- or C4-alkynyl this is preferably propargyl. If R5 signifies C3 6-alkenyl then this is preferably allyl (2-propenyl) and if Re signifies C2 6-alkenyl then this is preferably vinyl or 1-propenyl. When R5 signifies C3 6-alkynyl this is preferably propargyl.

The term "aryl" per se or as a part of "aryloxy" preferably signifies phenyl, although heterocyclic groups having aromatic character such as pyridyl, furyl and thienyl also come into consideration.

R2 preferably signifies optionally substituted 3-pyridyl, 2-pyrazinyl or 5-pyrimidinyl, as more precisely defined above, especially the unsubstituted groups.

R4 preferably represents a group (a).

Especially preferred compounds of formula I are: 2',5'-Dichloro-2-(2-pyrazinyl)-acetophenone O-methyl oxime, 2-(2-pyrazinyl)-4'-trifiuoromethyl-acetophenone O-methyl oxime, 2',4'-dichloro-2-(3-pyridyl)-4-pentenophenone O-methyl oxime, 2-bromo-2',4'-dichloro-2-(3-pyridyl)-acetophenone O-methyl oxime and 2',4'-dichloro-2-(3-pyridyl)-glycolophenone O-methyl oxime.

Other representative compounds of formula I are: 2',4'-Dimethyl-2-(2"-pyrazinyl)-acetophenone O-methy oxime 1"-oxide, 2',4'-dichloro-2-(5-pyrimidinyl)-acetophenone 0-methyl oxime, 2',4'-dichloro-2-(5-pyrimidinyl)-acetophenone O-allyl oxime, 2',4'-dichloro-2-(3-pyridyl)-acetophenone O-methoxyacetyl oxime, 3',5'-dichloro-2-(2-pyrazinyl )-acetophenone O-cyclopentyl oxime, 4'-cyano-2-(3-pyridyl)-acetophenone O-ethyl oxime, 2',4',5'-trifluoro-2-(2"-pyrazinyl)-butyrophenone O-methyl oxime 1",4"-dioxide, 3'-bromo-2-(5-methoxy-3-pyridyl)-propiophenone 0-(3-cyanopropyl) oxime, 2-(2'-pyrazinyl)-acetophenone O-(2-chloroethyl) oxime 4'-oxide, 4'-ethoxy-3'-methyl-2-(3"-pyridyl)-acetophenone O-cyclohexyloxime 1"-oxide, 3'-chloro-2-(5"-pyrimidinyl)-propiophenone O-propargyl oxime 1"-oxide, 2'-chloro-4'-trifluoromethyl-2-(2"-methyl-5"-pyrimidinyl)-acetophenone O-(2-phenylethyl) oxime 1",3"dioxide, 4'-(n-propyl)-2-(5"-chloro-3"-pyridyl)-acetophenone O-(4-methylphenyl) oxime 1"-oxide, 3',4'-dimethoxy-2-(5-pyrimidinyl)-propiophenone O-(4-nitrobenzyl) oxime, 2-(5"-methoxy-2"-pyrazinyl)-acetophenone 0-(4-ethoxy-3-methyl benzyl) oxime 4"-oxide, 2',4',5'-trimethyl-2-(5"-pyrimidinyl)-acetophenone 0-[3-(2,4-dinitrophenyl)-propyl] oxime 3"-oxide, 2'-chloro-4'-iodo-2-(5-pyrimidinyl)-butyrophenone 0-[2-(3,4,5-trichlorophenyl)-ethyl] oxime, 2',4'-dichloro-2-(5-methyl-3-pyridyl )-acetophenone O-chloroacetyl oxime, 2'-chloro-4'-trifluoromethyl-2-(2"-pyrazinyl)-propiophenone 0-(4-cyanobutyryl) oxime 1",3"-dioxide, 2-(2-pyrazinyl )-acetophenone 0-(3-phenyl-propionyl) oxime, 2'-methoxy-2-(3"-pyridyl)-acetophenone 0-(2,4-dichlorophenylacetyl) oxime 1 '-oxide, 4'-nitro-2-(5-chloro-2-pyrazinyl)-acetophenone O-[4-(4-ethoxyphenyl)-butyrl] oxime, 2',4'-dichloro-2-(5-pyrimidinyl)-acetophenone O-thioacetyl oxime, 4'-cyano-2'-chloro-2-(3-pyridyl)-4-pentenophenone O-(2,4-dichlorobenzoyl) oxime, 2-(4-chloro-5-pyrimidinyl)-propiophenone O-(3-phenoxypropionyl) oxime, 2',4'-dichloro-2-(3"-pyridyl)-acetophenone 0-(4-methylphenoxyacetyl) oxime 1"-oxide, 3'-methyl-2-(2-pyrazinyl )-acetophenone 0-[3-(2-nitro-4-propoxyphenoxy)-butyryl] oxime, 4'-chloro-2-(6-methyl-2-pyrazinyl )-acetophenone O-(n-butoxycarbonyl) oxime, 2-(5"-pyrimidinyl)-acetophenone O-(N-methycarbamoyl) oxime 3-oxide and 4'-ethoxy-2-(5-pyrimidinyl)-acetophenone O-[N,N-di-(n-pentyl)thiocarbamoyl] oxime.

Asymmetric carbon atoms can be present in the compounds of formula land accordingly the compounds can exist as optical antipodes. As a consequence of the presence of the C=N double bond and optionally also an aliphatic C=C double bond geometric isomerism occurs. Formula lis accordingly intended to embrace all of these possible isomeric forms.

An acid addition salts of the compounds of formula I there come into consideration physiologically compatible salts. These salts are preferably salts of the compounds of formula I with inorganic or organic acids such as hydrochloric acid, nitric acid, phosphoric acid, mono- and bifunctional carboxylic acids and hydroxycarboxylic acids (e.g. acetic acid, maleic acid, succinic acid, fumaric acid, tartaric acid, citric acid, salicyclic acid, sorbic acid and lactic acid) and sulphuric acids (e.g. 1 ,5-naphthalene-disulphonic acid). In the case of the N-oxides, i.e. the compounds of formula I in which R2 signifies 3-pyridyl 1-oxide, 2-pyrazinyl 1-oxide, 4-oxide and 1,4-dioxide, and 5-pyrimidinyl 1-oxide, 3-oxide and 1,3-dioxide, which are unsubstituted or substituted with methyl, methoxy or chlorine, there comes into consideration as acid addition salts especially physiologically compatible salts with strong acids such as inorganic acids (e.g. hydrochloric acid, nitric acid and phosphoric acid) and sulphonic acids (e.g. 1,5-naphthalene-disulphonic acid).

The process in accordance with the invention for the manufacture of the compounds of general formula I and of their acid addition salts comprises (a) reacting an oxime of the general formula

wherein R1 has the significance given above, R2 signifies 3-pyridyl, 2-pyrazinyl or 5-pyrimidinyl, the previous mentioned groups being optionally substituted with methyl, methoxy or chlorine, and R3 has the significance given above for R3 except chlorine, bromine or hydroxy, with a compound of the general formula R5,Y (Ill) wherein R5 has the significance given above for R5 except optionally substituted aryl and Y signifies a leaving group (e.g chlorine, bromine, iodine, mesyloxy ortosyloxy, especially chlorine, bromine or iodine), or with a reactive derivative of an acid of the general formula

wherein R6 and X have the significances given above, such as an acid halide, especially the acid chloride or acid bromide, the acid anhydride or, where R6 signifies C1-6-alkylamino, the (C1.6-alkyl)isocyanate or (C1 6-alkyl)-isothiocyanate, (b) reacting a ketone of the general formula

wherein R1, R2 and R3 have the significances given above, with an O-substituted hydroxylamine of the general formula RSONH2 VI wherein R5 has the significance given above for R5 except C3e-alkynyl, (c) treating a substituted acetophenone oxime of the general formula

wherein R', R2 and R4 have the significances given above, with a chlorinating or brominating agent, (d) treating a ketone of the general formula

wherein Ri, R2 and R4 have the significances given above, with a reducing agent, or (e) N-oxidizing a pyridine, pyrazine or pyrimidine derivative of the general formula

wherein R1, R2, R3 and R4 have the significances given above, and, if desired, converting a compound of general formula I obtained into an acid addition salt.

Compounds of formula I in which R2, R3 and R4 have the significance given above for R2, R3 and oR5 or X OCR6 can be manufactured by process variant (a).

When a compound of formula Ill is used as the reagent the process variant can be carried out by reacting an oxime of formula II with a compound of formula Ill conveniently in the presence of a base, in an organic solvent and in a temperature range between 0 C and the reflux temperature of the reaction mixture. The solvent can be protic or non-protic. When protic solvents such as alcohols, especially methanol or ethanol, are used, an alkali metal hydroxide (e.g. sodium or potassium hydroxide) or an alkali metal alcoholate is preferably used as the base. When non-protic solvents such as aliphatic or cyclic ethers especially tetrahydrofuran or dimethoxyethane, and dialkylamides, especially dimethylformamide, are used, an alkali metal hydride (e.g. sodium hydride) is preferably used as the base.In a preferred embodiment of this process variant sodium hydride is used as the base and an aliphatic or cyclic ether, especially tetrahydrofuran or dimethoxyethane, or a dialkylamide, especially dimethylformamide, is used as the solvent.

When a reactive derivative of an acid of formula IV is used as the reagent the reaction is conveniently carried out in the presence of a base such as sodium hydride or lithium diisopropylamide in an organic solvent such as an aliphatic or cyclic ether (e.g. dimethoxyethane or tetrahydrofuran) or a dialkylamide (e.g.

dimethylformamide) and in a temperature range between 0 C and the reluxtemperature of the reaction mixture, preferably between 0 C and room temperature. Pyridine is especially suitable as the base and simultaneously as the solvent.

In accordance with process variant (b), which leads to compounds of formula I in which R2, R3 and R4 have the significances given above for R2, R3 and OR5", respectively, the reaction is conveniently carried out in an organic solvent (e.g. an alcohol such as methanol or ethanol, a dialkylamide such as dimethylformamide or a tertiary amine such as pyridine). The reaction is preferably carried out in a temperature range between room temperature and the reflux temperature of the reaction mixture. Since the starting material of formula VI is preferably used in the form of acid addition salt (e.g. the hydrochloride or hydrosulphate), a base such as sodium or potassium carbonate, triethylamine or pyridine is conveniently added to the reaction mixture.

This process primarily comes into consideration for those cases in which R5 signifies unsubstituted C1 6-alkyl, C3 6-alkenyl or optionally substituted aryl-C1.3-alkyl or aryl, as more precisely defined above.

Process variant (c) leads to those compounds of formula I in which R2 has the significance given above for R2 and R3 signifies chlorine or bromine. As suitable halogenating agents there comes into consideration especially elementary chlorine or bromine, the halogenation conveniently being carried out in the presence of a halogenated hydrocarbon, such as chloroform or carbon tetrachloride, as the solvent. Other halogenating agents are, for example, sulphuryl chloride, which is used in an excess and can simultaneously serve as the solvent, and N-bromosuccinimide, which is conveniently used with the addition of a radical former such as benzoyl peroxide. In general, the suitable reaction temperature range between room temperature and the reflux temperature of the reaction mixture.

In accordance with process variant (d), which leads to those compounds of formula I in which R2 has the significance given above for R2 and R3 signifies hydroxy, the reduction is preferably carried out using sodium borohydride as the reducing agent, conveniently in a protic diluent such as an aliphatic alcohol (e.g.

methanol or ethanol) and at temperatures about room temperature.

Process variant (e) comprises N-oxidizing those end products of formula I in which R2 has the significances given above for R2'. The reaction can conveniently be carried out by N-oxidizing a compound of formula I" by means of hydrogen peroxide or a peracid in the presence of an inert diluent.

When hydrogen peroxide is used as the oxidizing agent there come into consideration as diluents especially lower alkanols such as methanol, ethanol and isopropanol, and the N-oxidation is preferably carried out in a temperature range between 0" and 60"C, especially between 20 and 40"C.

As peracids there comes into consideration preferably peracetic acid, perbenzoic acid and mchloroperbenzoic acid, the oxidation being preferably carried out in a halogenated hydrocarbon (e.g.

methylene chloride or chloroform) as the diluent. The N-oxidation with a peracid is preferably carried out in a temperature range between 0 C and the reflux temperature of the reaction mixture, especially between 0 C and room temperature. An especially preferred embodiment of this process variant comprises carrying out the N-oxidation with m-chloroperbenzoic acid in chloroform in a temperature range between 0 C and room temperature.

For the manufacture of acid addition salts, the compounds of formula I can, if desired, be reacted in a manner known per se with inorganic or organic acids such as, for example, hydrochloric acid, nitric acid, phosphoric acid, mono- and bifunctional carboxylic acids a nd and hydroxycarboxylic acids or sulphonic acids.

The isolation and purification of the thus-manufactured compounds of formula I and their acid addition salts are carried out according to methods known per se.

The oximes of formula II usable as starting materials can be prepared, for example, from the corresponding ketones of formula V, as defined above, by reaction with hydroxylamine in a manner known per se.

The ketones of formula V in which R2 signifies 3-pyridyl or 5-pyrimidinyl, which is unsubstituted or substituted with methyl, methoxy or chlorine, and R3 signifies hydrogen or Cm 4alkyl can be prepared, for example, by reacting a compound of the general formula

wherein R1 has the significance given above and Z signifies a disubstituted amino group (e.g. dimethylamino, diethylamino, piperidino or morpholino), with a halide of the general formula

wherein R2" signifies 3-pyridyl or 5-pyrimidinyl, which is unsubstituted or substituted with methyl, methoxy or chlorine, R3" signifies hydrogen or C14-alkyl and Hal signifies chlorine, bromine or iodine, and hydrolyzing the resulting product, which consists either of a compound of the general formula

or a compound of the general formula

or a mixture of the two compounds of formulae X and Xl. The reaction of a compound of formula VIII with a halide of formula IX can be carried out, for example, under the conditions of phase-transfer catalysis [see e.g.

J. Dockx, Synthesis (1973), 441] or using a base such as sodium hydride or lithium diisopropylamide in an organic solvent such as an aliphatic or cyclic ether (e.g. dimethoxyethane or tetrahydrofuran) and in a temperature range between -70 C and 50"C, preferably between -30 C and room temperature. Irrespective of the product distribution the thus-obtained crude products can thereupon be converted into a ketone of formula V by hydolysis (e.g. by conventional treatment with an aqueous acid). As acids there come into consideration for this purpose especially strong inorganic acids such as sulphuric acid, hydrogen chloride and hydrogen bromide as well as sulphonic acids such as benzenesulphonic acid and p-toluenesulphonic acid.In certain cases, for example when an intermediate of formula Xis formed, carboxylic acids such as acetic acid can be used. The hydrolysis is conveniently carried out in a temperature range between 20"C and the reflux temperature of the reaction mixture, preferably between 80" and 1 00 C.

The ketones of formula V in which R2 signifies 2-pyrazinyl, which is unsubstituted or substituted with methyl, methoxy or chlorine, and R3 signifies hydrogen or Cm 4alkyl can be prepared, for example, in accordance with the process described in DOS 2 800 010.

The remaining ketones of formula V, i.e. those in which R3 signifies C3- or C4-alkenyl or C3- or C4-alkynyl, as well as the ketones of formula V in which R3 signifies C1 4-alkyl (alternative method), can be prepared by reacting a ketone of the general formula

wherein R' and R2 have the significances given above, with a compound of the general formula R3,,,-U XII wherein R3 signifies C1.4-alkyl, C3- or C4-alkenyl or C3- or C4-alkynyl and U signifies a leaving group, especially chlorine, bromine or iodine.

The ketone is advantageously firstly converted with a base such as sodium hydride or lithium diisopropylamide in a diluent, preferably an aprotic organic solvent such as an aliphatic or cyclic ether (e.g.

dimethoxyethane ortetrahydrofuran) or a dialkyamide (e.g. dimethylformamide) at reaction temperatures between -70 C and 50"C into the anion, which can subsequently be reacted with a compound of formula XII in the same reaction medium.

The ketones of formula VII usable as starting materials can be prepared from the corresponding ketooximes of the general formula

wherein R1 and R2 have the significances given above, by reaction with the compounds of formula Ill, as defined above, namely under the same reaction conditions which have been described above in connection with process variant (a). The ketooximes of formula XIII are accessible from corresponding ketones of the general formula

wherein R1 and R2 have the significances given above, by treatment with nitrous acid or an alkyl nitrite in a manner known per se.

The compounds of formulae Ill, VI, VIII, IX, XII and XIV and reactive derivatives of the acids of formula IV usable as reagents or starting materials are either known or can be prepared according to methods known per se.

The compounds of formulae 1', I" and V' usable as starting materials are sub-classes of compounds of formula I or formula V, as appropriate.

The compounds in accordance with the invention, i.e. the compounds of formula I and their acid addition salts, have fungicidal activity and can accordingly be used for the control of fungi in agriculture and in horticulture. They are especially suitable for checking the growth or for the eradication of phytopathogenic fungi or parts of plants (e.g. leaves, stems, roots, tubers, fruits or flowers) and on seeds as well as in the soil and are especially effective in the control of Botrytis cinerea (grey mould); of powdery mildew fungi such as, for example, Uncinula necator (powdery mildew of vines), Erysiphe cichoracearum (powdery mildew of curcubits), Podosphaera leucotricha (powdery mildew of apples) and Erysiphe graminis (powdery mildew of cereals); of Venturia inaequalis (apple scab); of Helminthosporium oryzae (brown spot disease of rice); and of harmful fungi of the genera Puccinia, Uromyces, Rhizoctonia, Penicillium, Septoria and Cercospora.

Individual representatives of the compounds in accordance with the invention have, moreover, a pronounced activity against wood-destroying fungi such as, for example, Coniophora puteana and Gloeophyllum trabeum.

The compounds in accordance with the invention are distinguished by local and/or systemic activity.

The compounds in accordance with the invention are active under greenhouse conditions even at a concentration of 10 mg to 500 mg of active substance per litre of spray liquor. In the open, concentrations of 50 g to 2000 g of active substance of formula I per hectare and treatment are advantageously formed.

The compounds in accordance with the invention, namely the fungicidal active substances, can be converted using formulation adjuvants into the usual formulations such as dusts, powders, granulates, solutions, emulsions, suspensions, emulsifiable concentrates, pastes and the like. The fungicidal composition in accordance with the invention contains an effective amount of at least one compound of general formula I, as defined above, or an acid addition salt of such a compound as well as formulation adjuvants.

The compositions conveniently contain at least one of the following formulation adjuvants: Solid carrier substances; solvents or dispersion media; tensides (wetting and emulsifying agents); dispersing agents (withouttenside action); and stabilizers.

As solid carrier substances there essentially come into consideration: natural mineral substances such as kaolin, aluminas, siliceous earth, talc, bentonite, chalk (e.g. whiting), magnesium carbonate, limestone, quartz dolomite, attapulgite, montmorrillonite and diatomaceous earth; synthetic mineral substances such as highly dispersible silicic acid, aluminium oxide and silicates; organic substances such as cellulose, starch, urea and synthetic resins; and fertilizers such as phosphates and nitrates, whereby such carrier substances can be present, for example, in the form of granulates or powders.

As solvents or dispersion media there essentially come into consideration: aromatic such as benzene, toluene, xylenes and alkylnaphthalenes; chlorinated aromatics and chlorinated aliphatic hydrocarbons such as chlorobenzenes, chloroethylenes and methylene chloride; aliphatic hydrocarbons such as cyclohexane and paraffins (e.g. petroleum fractions); alcohols such as butanol and glycol as well as their ethers and esters; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexane; and strongly polar solvents or dispersion media such as dimethylformamide, N-methylpyrrolidone and dimethyl sulphoxide, such solvents or dispersion media preferably having flash points of at least 30"C and boiling points of at least 500C, and water.Amongst the solvents or dispersion media there also come into consideration so-called liquified gaseous extenders or carrier substances, which are those products which are gaseous at room temperature and under normal pressure. Examples of such products are especially aerosol propellants such as halogenated hydrocarbons (e.g. dichlorodifluoromethane). When water is used as the solvent, organic solvents can, for example, also be used as auxiliary solvents.

The tensides (wetting and emulsifying agents) can be non-ionic compounds such as condensation products of fatty acids, fatty alcohols or fatty-substituted phenols with ethylene oxide; fatty acid esters and ethers of sugars or polyvalent alcohols; the products which are obtained from sugars or polyvalent alcohols by condensation with ethylene oxide; block polymers of ethylene oxide and propylene oxide; or alkyldimethylamine oxides.

The tensides can also be anionic compounds, such as soaps; fatty sulphate esters (e.g. dodecyl sodium sulphate, octadecyl sodium sulphate and cetyl sodium sulphate); alkyl sulphonates, aryl sulphonates and fatty-aromatic sulphonates such as alkylbenzene sulphonates (e.g. calcium dodecylbenzene sulphonate) and butylnaphthalene sulphonates; and more complex fatty sulphonates (e.g. the amide condensation products of oleic acid and N-methyltaurine and the sodium sulphonate of dioctyi succinate).

Finally, the tensides can be cationic compounds such as alkyldimethylbenzylammonium chlorides, dialkyldimethylammonium chlorides, alkyltrimethylammonium chlorides and ethoxylated quaternary ammonium chlorides.

As dispersing agents (without tenside action) there essentially come into consideration: lignin, sodium and ammonium salts of lignin sulphonic acids, sodium salts of maleic anhydride-diisobutylene copolymers, sodium and ammonium salts of sulphonated polycondensation products of naphthalene and formaldehyde, and sulphite lyes.

As dispersing agents, which are especially suitable as thickening or anti-settling agents, there can be used, for example, methylcellulose, carboxymethylcellulse, hydroxyethylcellulose, polyvinyl alcohol, alginates, caseinates and blood albumin.

Examples of suitable stabilizers are acid-binding agents (e.g. epichlorohydrin, phenyl glycidyl ether and soya epoxides); antioxidants (e.g. gallic acid esters and butylhydroxytoluene); UV-absorbers (e.g.

substituted benzophenones, diphenylacrylonitrile acid esters and cinnamic acid esters); and deactivators (e.g. salts of ethylenediaminotetraacetic acid and polyglycols).

The fungicidal compositions in accordance with the invention can contain, in addition to the active substances of formula I, other active substances (e.g. otherfungicidal agents, insecticidal and acaricidal agents, bactericides, plant growth regulators and fertilizers). Such combination compositions are suitable for broadening the spectrum of activity or for specifically influencing the plant growth.

The fungicidal compositions in accordance with the invention generally contain, according to type, between 0.0001 and 95 weight percent of a compound in accordance with the invention or compounds in accordance with the invention as the active substance(s). They can be present in a form which is suitable for storage and transport. In such forms (e.g. emulsifiable concentrates) the active substance concentration is normally in the higher region of the above concentration range. These forms can be diluted with the same or different formulation adjuvants to give active substance concentrations which are suitable for practical use, and such concentrations normally lie in the lower region of the above concentration range. Emulsifiable concentrates generally contain 5 to 95 weight percent, preferably 25 to 75 weight percent, of a compound or compounds of formula I.As forms of use there come into consideration, inter alia, ready-for-use solutions, emulsions and suspensions which are suitable, for example, as spray liquors. In such spray liquors there can be present, for example, concentrations between 0.0001 and 20 weight percent. In the Ultra-Low-Volume process there can be formulated spray liquors in which the active substance concentration is preferably from 0.5 to 20 weight percent, while the spray liquors formulated in the Low-Volume process and in the High-Volume process preferably have an active substance concentration of 0.02 to 1.0 weight percent or 0.002 to 0.1 weight percent, respectively.

The fungicidal compositions in accordance with the invention can be manufactured by mixing at least one compound or general formula I or an acid addition salt of such a compound with formulation adjuvants.

The manufacture of the compositions can be carried out in a known manner; for example, by mixing the active substance with solid carrier substances, by dissolution or suspension in suitable solvents or dispersion media, if necessary with the use of tensides as wetting or emulsifying agents or of dispersing agents, by diluting pre-prepared emulsifiable concentrates with solvents or dispersion media etc.

In the case of pulverous compositions the active substances can be mixed with a solid carrier substance (e.g. by grinding them together) or the solid carrier substance can be impregnated with a solution or suspension of the active substance and then the solvent or dispersion medium can be removed by evaporation, heating or sucking-off under reduced pressure. By adding tensides or dispersing agents such pulverous compositions can be made readily wettable with water, so that they can be converted into aqueous suspensions which are suitable, for example, as spray compositions.

The compounds in accordance with the invention can also be mixed with a tenside and a solid carrier substance to form a wettable powder which is dispersible in water, or they can be mixed with a solid pre-granulated carrier substance to give a product in the form of a granulate. When desired, a compound in accordance with the invention can be dissolved in a water-immiscible solvent such as, for example, an alicylic ketone, which conveniently contains dissolved emulsifying agent, so that the solution becomes self-emulsifying upon addition to water. Alternatively, the active substance can be mixed with an emulsifying agent and the mixture can then be diluted with water to give the desired concentration. Moreover, the active substance can be dissolved in a solvent and thereafter the solution can be mixed with an emulsifying agent.Such a mixture can likewise be diluted with water to give the desired concentration. In this manner there are obtained emulsifiable concentrates and ready-for-use emulsions.

The use of the composition in accordance with the invention can be carried out according to the application methods which are usual in plant protection or in agriculture such as sprinkling, spraying, dusting, pouring or scattering. The method in accordance with the invention for the control of fungi comprises treating the locus to be protected (e.g. plants, parts of plants or seeds) with an effective amount of a compound in accordance with the invention or of a composition in accordance with the invention.

The following Examples illustrate the invention.

Manufacture of the active substances Example 1 6 g of 2',4'-dichloro-2-(2-pyrazine)-acetophenone oxime are dissolved in 80 ml of dimethylformamide and the solution is treated with 1.25 g of sodium hydride (about 50% dispersion in mineral oil). After stirring at room temperature for 1 hour 5.2 g of 2,4-dichlorobenzyl chloride are added thereto and the mixture is left to react at room temperature for 16 hours. The mixture is then poured into ice-water and extracted with ethyl acetate. The organic phase is dried over anhydrous sodium sulphate and concentrated. The crude product is subjected to column chromatography on silica gel with ethyl acetate/n-hexane (1:1). There is obtained 2',4'-dichloro-2-(2-pyrazinyl)-acetophenone O-(2,4-dichlorobenzyl) oxime in the form of a yellowish oil.

In an analogous manner, from 2',4'-dichloro-2-(3-pyridyl)-acetophenone oxime and benzyl chloride there is obtained 2',4'-dichloro2-(3-pyridyl)-acetophenone O-benzyl oxime in the form of a yellowish oil and from 2',4'-dichlorn-2-(3-pyridyl)-acetophenone oxime and 3-picolyl chloride hydrochloride there is obtained 2',4'-dichloro-2-(3-pyridyl)-acetophenone O-(3-pyridylmethyl) oxime in the form of an oil.

Example 2 3 g of 2',4'-dichloro-2-(2-pyrazinyl)-acetophenone oxime are dissolved in 20 ml of pyridine and the solution is treated with 0.7 g of methyl isocyanate. After stirring at room temperature for 2 hours a further 0.7 g of methyl isocyanate is added. After a further 2 hours the mixture is poured into ice-water and extracted with ethyl acetate. The organic phase is dried over anhydrous sodium sulphate and subsequently concentrated. The residue is subjected to column chromatography on silica gel with ethyl acetate/n-hexane (1:1). There is obtained 2,4-dichloro-2-(2-pyrazinyl)-acetophenone O-[(methylamino)-carbonyl] oxime in the form of a yellowish oil.

Example 3 3 g of 2-(2-pyrazinyl)-acetophenone and 2.5 g of O-methylhydroxylamine hydrochloride are heated to 80"C for 30 minutes in 10 ml of pyridine. The pyridine is the distilled off under reduced pressure, the residue is treated with water and the aqueous phase is extracted with ethyl acetate. The organic phase is then dried over anhydrous sodium sulphate and the solvent is removed. As the residue there is obtained 2-(2-pyrazinyl)-acetophenone O-methyl oxime in the form of a yellowish oil.

In an analogous manner, from 2',5'-dichloro-2-(2-pyrazinyl)-acetophenone and O-methylhydroxylamine hydrochloride there is obtained 2',5'-dichloro-2-(2-pyrazinyl)-acetophenone O-methyl oxime in the form of a yellowish oil, from 3'-chloro-2-(2-pyrazinyl)-acetophenone and O-methylhydroxylamine hydrochloride there is obtained 3'-chloro-2-(2-pyrazinyl)-acetophenone O-methyl oxime in the form of a yellowish oil, from 2',4'-dimethyl-2-(2-pyrazinyl)-acetophenone and O-methylhyd roxylamine hydrochloride there is obtained 2',4'-dimethyl-2-(2-pyrazinyl)-acetophenone O-methyl oxime in the form of a yellowish oil, from 4'-methoxy-2-(2-pyrazinyl)-acetophenone and O-methylhydroxylamine hydrochloride there is obtained 4'-methoxy-2-(2-pyrazinyl)-acetophenone O-methyl oxime, m.p. 58-60"C, from 2-(2-pyrazinyl)-4'-trifluoromethyl-acetophenone and O-methylhydroxylamine hydrochloride there is obtained 2-(2-pyrazinyl)-4'-trifluoromethyl-acetophenone O-methyl oxime, m.p. 45-47"C, from 3',4'-dichloro-2-(2-pyrazinyl)-acetophenone and O-methylhydroxylamine hydrochloride there is obtained 3',4'-dichloro-2-(2-pyrazinyl)acetophenone O-methyl oxime in the form of a yellowish oil, from 4'-chloro-2'-methoxy-2-(2-pyrazinyl)acetophenone and O-methylhydroxylamine hydrochloride there is obtained 4'-chloro-2'-methoxy-2-(2-pyrazinyl)-acetophenone O-methyl oxime in the form of a yellowish oil, from 2',4'-dichloro-2-(6-methyl-2-pyrazinyl)-acetophenone and O-methylhydroxylamine hydrochloride there is obtained 2',4'-dichloro-2-(6-methyl-2-pyrazinyl)-acetophenone O-methyl oxime in the form of a yellowish oil, from 2',4'-dichloro-2-(5-methyl-2-pyrazinyl)-acetophenone and O-methylhydroxylamine hydrochloride there is obtained 2',4'-dichloro-2-(5-methyl-2-pyrazinyl)-acetophenone O-methyl oxime in the form of a yellowish oil, from 2',4'-dichloro-2-(3-pyridyl)-acetophenone and 0-(2,6-dichlorobenzyl)-hydroxylamine hydrochlorice there is obtained 2',4'-dichloro-2-(3-pyridyl)-acetophenone O-(2,6-dichlorobenzyl) oxime in the form of a yellowish oil, from 4'-nitro-2-(3-pyridyl)-acetophenone and O-methylhydroxylamine hydrochloride there is obtained 4'-nitro-2-(3-pyridyl)-acetophenone O-methyl oxime, m.p. 114-116"C, from 2',4'-dichloro-2-(3-pyridyl)-acetophenone and O-phenylhydroxylamine hydrochloride there is obtained 2',4'-dichloro-2-(3-pyridyl)-acetophenone O-phenyl oxime in the form of a yellowish oil, from 2',4'-dichloro-2-(3-pyridyl)-4-pentenophenone and O-methylhydroxylamine hydrochloride there is obtained 2',4'-dichloro-2-(3-pyridyl)-4-pentenophenone O-methyl oxime in the form of an oil and from 2',4'-dichloro-2-(3-pyridyl)-4-pentynophenone and O-methylhydroxylamine hydrochloride there is obtained 2',4'-dichloro-2-(2-pyridyl)-4-pentynophenone O-methyl oxime in the form of a brownish oil.

Example 4 1 g of 1-(2,4-dichlorophenyl)-2-(3-pyridyl)-glyoxal-1-O-methyl oxime is dissolved in 10 ml of methanol and the solution is treated with 0.18 g of sodium borohydride. After a reaction time of about 2 hours at room temperature the mixture is poured into water and extracted with ethyl acetate. The organic phase is dried over anhydrous sodium sulphate and concentrated. There is obtained 2',4'-dichloro-2-(3-pyridyl)glycolophenone O-methyl oxime in the form of a yellowish oil.

Example 5 10 g of 2',4'-dichloro-2-(3-pyridyl)-acetophenone O-methyl oxime, 7.1 g of N-bromosuccinimide and 50 mg of dibenzoyl peroxide in 100 ml of carbon tetrachloride are heated under reflux for 3 hours, a further 4.5 g of N-bromosuccinimide are then added and the mixture is heated for a further 2 hours. The mixture is then filtered and the filtrate is poured into sodium bicarbonate solution and extracted with ethyl acetate. The crude product remaining after removal of the solvent is chromatographed on silica gel with n-hexane/ethyl acetate (1: 1). There is obtained 2-bromo-2',4'-dichloro-2-(3-pyridyl)-acetophenone O-methyl oxime in the form of a yellowish, slightly stable oil.

2.8 g of this oil are taken up in 20 ml of ethyl acetate and treated at 0 C with 0.74 g of concentrated sulphuric acid. After stirring at room temperature for 1 hour the solvent is removed. As the residue there is obtained 2-bromo-2',4'-dichloro-2-(3-pyridyl)-acetophenone O-methyl oxime sulphate in the form of a wax-like solid.

Example 6 3 g of 2',4'-dichloro-2-(3-pyridyl)-acetophenone oxime are dissolved in 20 ml of pyridine and the solution is treated with 1.8 g of benzoyl chloride. The mixture is then stirred at room temperature for 24 hours and subsequently concentrated under reduced pressure. The residue is taken up in 1N sodium hydroxide and extracted with methylene chloride. After removing the solvent there is obtained a crude product which is purified by chromatography on silica gel with n-hexane/ethyl acetate (1:1). There is obtained 2',4'-dichloro2-(3-pyridyl)-acetophenone O-benzoyl oxime in the form of a brownish oil.

In an analogous manner, from 2',4'-dichloro-2-(3-pyridyl)-acetophenone oxime and crotonyl chloride there is obtained 2',4'-dichloro-2-(3-pyridyl)-acetophenone O-crotonyl oxime in the form of a brownish oil.

II. Formulation Examples Example 7 1. Spray powder (for active substances which are liquid or which melt below 75"C) Parts by weight Active substance of formula 1 50 Hydrated silicic acid 37 Kaolin 5 Alkylphenol ethoxylate 4 Sodium polynaphthalenesulphonate 4 100 The liquid or molten active substance is taken up on the silicic acid, the remaining components are admixed and the mixture is finely ground in a suitable mill.

2. Spray powder (for solid active substances which melt above 75"C) Parts by weight Active substance of formula 1 50 Hydrated silicic acid 5 Kaolin 42 Sodium lauryl sulphate 1 Sodium lignosulphonate 2 100 The components are mixed with one another and the mixture is finely ground in a suitable mill.

Example 8 Emulsifiable concentrate (for active substances which are liquid at 20-25"C) Parts by weight Active substance of formula 1 500 Castor oil ethoxylate 100 Calcium dodecylbenzenesulphonate 25 Mixtures of C10-alkylbenzenes ad 1000 parts by volume.

The components are mixed with one another until a clear solution is obtained.

Claims

1. Compounds of the general formula

wherein R1 signifies unsubstituted or monol, di- or trisubstituted phenyl, the optionally present substituents being selected from 1 to 3 halogen atoms, 1 to 3 C1 3-alkyl groups, 1 or2C13-alkoxyl groups, a trifluoromethyl group, a cyano group and a nitro group, R2 signifies 3-pyridyl, 3-pyridyl 1-oxide, 2-pyrazinyl, 2-pyrazinyl 1-oxide, 2-pyrazinyl 4-oxide, 2-pyrazinyl 1,4-dioxide, 5-pyrimidinyl, 5-pyrimidinyl 1-oxide, 5-pyrimidinyl 3-oxide or 5-pyrimidinyl 1,3-dioxide, the previously named groups being optionally substituted with methyl, methoxy or chlorine, R3 signifies hydrogen, C1.4-alkyl, C3- or C4-alkenyl, C3- or C4-alkynyl, chlorine, bromine or hydroxy, and R4 represents a group oR5 (a) or

wherein R5 is unsubstituted C1.6-alkyl or C1.6-alkyl monosubstituted with halogen, C1 3-alkoxy or cyano; C3.5- cycloalkyl; C3 6-alkenyl; C3 6-alkynyl; unsubstituted aryl-C1.3-alkyl or aryl; or aryl-C1.3-alkyl or aryl mono, di- or trisubstituted in the aryl nucleus, the substitutents being selected from 1 to 3 halogen atoms, a C1.3-alkyl group, a C1.3-alkoxy group and 1 to 3 nitro groups, R6 is unsubstituted C1.6-alkyl or C1.6-alkyl monosubstituted with halogen, C1.3-alkoxy or cyano; unsubsti tuted aryl-C1.3-alkyl or aryl-C1.3-alkyl mono, di ortrisubstituted in the aryl nucleus; C3 6-cycloalkyl; C2.6-alkenyl; unsubstituted or mono-, di ortrisubstituted aryl; unsubstituted aryloxy-C1.3-alkyl or aryloxy-C1.3-alkyl mono, di ortnsubstftuted in the aryl nucleus; C1.6-alkoxy; C1.6-alkylamino; or di(C1.6-alkyl)amino, the optionally present substituents in the aryl nucleus being selected from 1 to 3 halogen atoms, a C1.3-alkyl group, a C1.3-alkoxy group and 1 to 3 nitro groups, and X signifies oxygen or sulphur, with the proviso that where simultaneously R1 signifies phenyl substituted with 1 to 3 halogen atoms, R2 signifies 3-pyridyl, 3-pyridyl 1-oxide, 2-pyrazinyl, 2-pyrazinyl 1-oxide, 2-pyrazinyl 4-oxide or 2-pyrazinyl 1,4-dioxide, R3 signifies hydrogen or C1 4-alkyl, R4 signifies a group (a) and R5 signifies unsubstituted C1.6-alkyl, C3.6-cycloalkyl, C3 6-alkenyl or C3 6-alkynyl, R1 can only be 3-halophenyl, 2,3-, 2,5-, 3,4- or 3,5-dihalophenyl or 2,3,4-, 2,3,5- or 2,4,5-trihalophenyl, and acid addition salts of these compounds.

2. Compounds according to claim 1, wherein R2 signifies 3-pyridyl, 2-pyrazinyl or 5-pyrimidinyl.

3. Compounds according to claim 1 or claim 2, wherein R4 represents a group (a).

4. 2',5'-Dichloro-2-(2-pyrazinyl)-acetophenone 0-methyl oxime.

5. 2-(2-Pyrazinyl)-4'-trifluoromethyl-acetophenone 0-methyl oxime.

6. 2',4'-Dichloro-2-(3-pyridyl)-4-pentenophenone O-methyl oxime.

7. 2-Bromo-2',4'-dich loro-2-(3-pyridyl )-acetophenone O-methyl oxime.

8. 2',4'-Dichloro-2-(3-pyridyl)-glycolophenone O-methyl oxime.

9. Acompound according to claim 1, selected from: 2,4'-Dichloro-2-(2-pyrazinyl )-acetophenone 0-(2,4-dichlorobenzyl) oxime, 2',4'-dichloro-2-(3-pyridyl)-acetophenone O-benzyl oxime, 2',4'-dichloro-2-(3-pyridyl)-acetophenone 0-(3-pyridylmethyl) oxime, 2',4'-dichloro-2-(2-pyrazinyl)-acetophenone O-[(methylamino)carbonyl] oxime, 2-(2-pyrazinyl )-acetophenone O-methyl oxime, 3'-chloro-2-(2-pyrazinyl)-acetophenone O-methyl oxime, 2',4'-dimethyl-2-(2-pyrazinyl)-acetophenone O-methyl oxime, 4'-methoxy-2-(2-pyrazinyl)-acetophenone O-methyl oxime, 3',4'-dichloro-2-(2-pyrazinyl)-acetophenone O-methyl oxime, 4'-chloro-2'-methoxy-2-(2-pyrazinyl )-acetophenone O-methyl oxime, 2',4'-dichloro-2-(6-methyl-2-pyrazinyl )-acetophenone O-methyl oxime, 2',4'-dichloro-2-(5-methyl-2-pyrazinyl)-acetophenone O-methyl oxime, 2',4'-dichloro-2-(3-pyridyl)-acetophenone 0-(2,6-dichlorobenzyl) oxime, 4'-nitro-2-(3-pyridyl)-acetophenone O-methyl oxime, 2',4'-dichloro-2-(3-pyridyl)-acetophenone O-phenyl oxime, 2',4'-dichloro-2-(3-pyridyl)-4-pentynophenone Methyl oxime, 2',4'-dichloro-2-(3-pyridyl)-acetophenone O-benzoyl oxime and 2',4'-dichlorn-2-(3-pyridyl)-acetophenone O-crotonyl oxime.

10. Compounds according to any one of claims 1 to 9 as fungicidal active substances.

11. A fungicidal composition which contains an effective amount of at least one compound of the general formula

wherein R1 signifies unsubstituted or mono-, di or trisubstituted phenyl, the optionally present substituents being selected from 1 to 3 halogen atoms, 1 to 3 C1 3-alkyl groups, 1 or 2 C1.3-alkoxy groups, a trifluoromethyl group, a cyano group and a nitro group, R2 signifies 3-pyridyl, 3-pyridyl 1-oxide, 2-pyrazinyl, 2-pyrazinyl 1-oxide, 2-pyrazinyl 4-oxide, 2-pyrazinyl 1,4-dioxide, 5-pyrimidinyl, 5-pyrimidinyl 1-oxide, 5-pyrimidinyl 3-oxide or 5-pyrimidinyl 1,3-dioxide, the previously mentioned groups being optionally substituted with methyl, methoxy or chlorine, R3 signifies hydrogen, C1.4-alkyl, C3- or C4-alkenyl, C3- or C4-alkynyl, chlorine, bromine or hydroxy and R4 represents a group OR5 (a) or

wherein R5 is unsubstituted C1 6-alkyl or Clg-alkyl monosubstituted with halogen, C13-alkoxy or cyano; C3- cycloalkyl; C3 6-alkenyl; C3 6-alkynyl; unsubstituted aryl-C1 3-alkyl or aryl; or aryl-C1 3-alkyl or aryl mono-, di- ortrisubstituted in the aryl nucleus, the substituents being selected from 1 to 3 halogen atoms, a C1-3-alkyl group, a C1 3-alkoxy group and 1 to 3 nitro groups, R6 is unsubstituted C1.6-alkyl or C1 6-alkyl monosubstituted with halogen, C1 3-alkoxy or cyano; unsubsti tuted aryl-C1-3-alkyl or aryl-C1 3-alkyl mono-, di ortrisubstituted in the aryl nucleus;C3.6-cycloalkyl; C2.6-al kenyl; unsubstituted or mono-, di- or trisu bstituted aryl; unsu bstituted aryloxy-C1.3-al kyl or aryloxy-C13-alkyl mono-, di- or trisubstituted in the aryl nucleus; c1 6-alkoxy; C1.e-alkylamino;; or di(C1.8-alkyl)amino, the optionally present substituents in the aryl nucleus being selected from 1 to 3 halogen atoms, a C1.3-alkyl group, a C1.3-alkoxy group and 1 to 3 nitro groups, and X signifies oxygen or sulphur, with the proviso that where simultaneously R1 signifies phenyl substituted with 1 to 3 halogen atoms, R2 signifies 3-pyridyl, 3-pyridyl 1-oxide, 2-pyrazinyl, 2-pyrazinyl 1-oxide, 2-pyrazinyl 4-oxide or 2-pyrazinyl 1,4-dioxide, R3 signifies hydrogen or C1.4-alkyl, R4 signifies a group (a) and R5 signifies unsubstituted C1 6-alkyl, C3.e-cycloalkyl, C3 6-alkenyl or C3 6-alkynyl, R1 can only be 3-halophenyl, 2,3-, 2,5-, 3,4- or 3,5-dihalophenyl or 2,3,4-, 2,3,5- or 2,4,5-trihalophenyl, or an acid addition salt of such a compound, as well as formulation adjuvants.

12. Afungicidal composition according to claim 11 which contains an effective amount of 2',5'-dichloro-2-(2-pyrazinyl)-acetophenone O-methyl oxide, 2-(2-pyrazinyl )-4'-trifluoromethyl-acetophenone O-methyl oxime, 2',4'-dichloro-2-(3-pyridyl)-4-pentenophenone O-methyl oxime, 2-bromo-2',4'-dichloro-2-(3-pyridyl)-acetophenone O-methyl oxime or 2',4'-dichloro-2-(3-pyridyl)-glycolophenone O-methyl oxime or an acid addition salt of such a compound, as well as formulation adjuvants.

13. A process for the manufacture of compounds of the general formula

wherein R1 signifies unsubstituted or mono-, di- or trisubstituted phenyl, the optionally present substituents being selected from 1 to 3 halogen atoms, 1 to 3 C1-3-alkyl groups, 1 to 2 C1.Balkoxy groups, a trifluoromethyl group, a cyano group and a nitro group, R2 signifies 3-pyridyl, 3-pyridyl 1-oxide, 2-pyrazinyl, 2-pyrazinyl 1-oxide, 2-pyrazinyl 4-oxide, 2-pyrazinyl 1,4-dioxide, 5-pyrimidinyl, 5-pyrimidinyl 1-oxide, 5-pyrimidinyl 3-oxide or 5-pyrimidinyl 1 ,3-dioxide, the previously named groups being optionally substituted with methyl, methoxy or chlorine, R3 signifies hydrogen, C14-alkyl, C3- or C4-alkenyl, C3- or C4-alkynyl, chlorine, bromine or hydroxy and R4 represents a group OR5(a) or

wherein R5 is unsubstituted C1- 6-alkyl or C1.G-alkyl monosubstituted with halogen, C1.3-alkoxy or cyano; C3.6- cycloalkyl; C3 6-alkenyl; C3 6-alkynyl; unsubstituted aryl-C1.3-alkyl or aryl; or aryl-C1.3-alkyl or aryi mono-, di ortrisubstituted in the aryl nucleus, the substituents being selected from 1 to 3 halogen atoms, a Cm 3alkyl group, a C1.3-alkoxy group and 1 to 3 nitro groups, R6 is unsubstituted C1-6-alkyl or cur 6alkyl monosubstituted with halogen, C1.B-alkoxy or cyano; unsubsti tuted aryl-C1.3-alkyl or aryl-C1.3-alkyl mono-, di- ortrisubstituted in the aryl nucleus; C3.5-cycloalkyl; C2 6-alkenyl; unsubstituted or mono-, di- ortrisubstituted aryl; unsubstituted aryloxy-C1.3-alkyl or aryloxy-C1.3-alkyl mono-, di- or trisubstituted in the aryl nucleus; C1.e-alkoxy; C, 6-alkylamino;; or di(C1.6-alkyl)amino, the optionally present substituents in the aryl nucleus being selected from 1 to 3 halogen atoms, a C1-3-alkyl group, a C1.B-alkoxy group and 1 to 3 nitro groups, and X signifies oxygen or sulphur, with the proviso that where simultaneously R1 signifies phenyl substituted with 1 to 3 halogen atoms, R2 signifies 3-pyridyl, 3-pyridyl 1-oxide, 2-pyrazinyl, 2-pyrazinyl 1-oxide, 2-pyrazinyl 4-oxide or 2-pyrazinyl 1,4-dioxide, R3 signifies hydrogen or C1.4-alkyl, R4 signifies a group (a) and R5 signifies unsubstituted C1.6-alkyl, C3.6-cycloalkyl, C3 6-alkenyl or C3 6-alkynyl, R1 can only be 3-halophenyl, 2,3-, 2,5-, 3,4- or 3,5-dihalophenyl or 2,3,4-, 2,3,5- or 2,4,5-trihalophenyl, and of their acid addition salts, which process comprises (a) reacting an oxime of the general formula

wherein R1 has the significance given earlier in this claim, R2 signifies 3-pyridyl, 2-pyrazinyl or 5-pyrimidinyl, the previously mentioned groups being optionally substituted with methyl, methoxy or chlorine, and R3 has the significance given earlier in this claim for R3 except chlorine, bromine or hydroxy, with a compound of the general formula R5,Y Ill wherein R5 has the significance given earlier in this claim for R5 except optionally substituted aryl and Y signifies a leaving group, or with a reactive derivative of an acid of the general formula

wherein R6 and X have the significance given earlier in this claim, (b) reacting a ketone of the general formula

wherein R1, R2 and R3 have the significances given earlier in this claim, with an O-substituted hydroxylamine of the general formula R5,,ONH2 VI wherein R5 has the significance given earlier in this claim for R5 except for C3 6-alkynyl, (c) treating a substituted acetophenone oxime of the general formula

wherein R1, R2 and R4 have the significances given earlier in this claim, with a chlorinating or brominating agent, (d) treating a ketone of the general formula

wherein R1, R2 and R4 have the significances given earlier in this claim, with a reducing agent, or (e) N-oxidizing a pyridine, pyrazine or pyrimidine derivative of the general formula

wherein R1, R2, R3 and R4 have the significances given earlier in this claim, and, if desired, converting a compound of general formula I obtained into an acid addition salt

14. A method for the control of fungi in agriculture and in horticulture, which method comprises treating the locus to be protected with an effective amount of one of the compounds set forth in claims 1 to 9 or of a composition set forth in claim 11 or claim 12.

15. The use of one of the compounds set forth in claims 1 to 9 or of a composition set forth in claim 11 or claim 12 for the control of fungi in agriculture and in horticulture.

16. A fungicidal composition according to claim 11, substantially as described herein with reference to Example 7 or 8.

17. A process according to claim 13, substantially as described with reference to any one of Examples 1 to 6.