GB2197866A - Fungicidal oxime derivatives - Google Patents

Abstract

Compounds having the general formula (I): <IMAGE> in which R and R<2> are independently alkyl, cycloalkyl, cycloalkylalkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted benzyl or a metal ion; and R<1> is alkyl substituted by cyano or thiocarbamoyl, the alkyl group being optionally substituted, in addition, by optionally substituted aryl or optionally substituted heterocyclyl, have fungicidal properties.

Description

ChEMICAL COMPOUNDS This invention relates to oxime derivatives useful as fungicides, to processes for preparing them, to fungicidal compositions containing them and to methods of combating fungi, particularly fungal infections in plants.

The invention provides compounds having the general formula (I)

in which R and R2 are independently alkyl, cycloalkyl, cycloalkylalkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted benzyl or a metal ion; and R1 is alkyl substituted by cyano or thiocarbamoyl, the alkyl group being optionally substituted, in addition, by optionally substituted aryl or optionally substituted heterocyclyl.

When R or R2 is an alkyl group it may contain from 1-4 carbon atoms, examples of which are methyl, ethyl, isopropyl, and n-butyl or t-butyl.

A particularly preferred value of R or R2 is methyl.

When R or R2 is a cycloalkyl group, it may be, for example, a C36 cycloalkyl group, ie. a cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl group.

When R or R2 is cycloalkylalkyl group, it may be, for example, a C4-7 cycloalkylalkyl group, for example, a cyclopropylmethylf cyclopentylmethyl or cyclohexylmethyl group.

When R or R2 is an optionally substituted alkenyl or alkynyl group, it may be, for example, a C35 alkenyl or C3-5 alkynyl group. Examples include allyl and propargyl.

Examples of substituents in a substituted alkenyl or alkynyl group include C14 alkyl (eg. methyl) or halogen (eg. chlorine, fluorine, bromine or iodine).

When R or R2 is a benzyl group, the benzyl group can be unsubstituted or substituted by halogen (eg. fluorine, chlorine or bromine), C1~4 alkyl (eg. methyl, ethyl, isopropyl or t-butyl), 1-4 alkoxy (eg. methoxy or ethoxy), nitro or haloalkyl (eg. trifluoromethyl). Examples of these groups are benzyl, 4-chlorobenzyl, 2,4dichlorobenzyl, 2-nitrobenzyl, and 3-trifluoromethylbenzyl.

When R or R2 is a metal ion, it may be, for example, sodium, potassium, copper or iron.

R1 is alkyl substituted by cyano or thiocarbamoyl in which the alkyl group, which may contain from 1 to 10 carbon atoms in straight or branched chains, may additionally be substituted by (i) aryl (eg. phenyl) optionally substituted by, for example, C14 alkyl (eg.

methyl), halogen (eg. chlorine, fluorine, bromine or iodine), C14 alkoxy (eg. methoxy), nitro, haloalkyl (eg.

trifluoromethyl), or cyano, or (ii) heterocyclyl (eg. 2furyl, 2-thienyl) optionally substituted by, for example, C1-4 alkyl (eg. methyl), halogen (eg. chlorine or bromine), nitro, haloalkyl (eg. trifluoromethyl) or cyano.

In a preferred aspect, the invention provides compounds having the general formula (I)

in which R and R2 are independently C14 alkyl (especially methyl), C3-5 alkenyl (especially allyl) or C3-5 alkynyl (especially propargyl) and R1 is cyanoalkyl in which the alkyl group contains from 1 to 6 (especially 1 to 4 and more especially 2 to 4) carbon atoms and is optionally substituted by C14 alkyl (especially methyl), phenyl, or heterocyclyl (especially furyl), or R1 is C16 (especially C1-4 and more especially C2~4) alkyl substituted by thiocarbamoyl.

Of particular interest are compounds in which both R and R2 are methyl and R1 is cyano (C2-4) alkyl.

Examples of the compounds of the invention are shown in Table I below in which the different values for R, R and R2 are displayed.

TABLE I

Compound | R l R1 R2 Melting No. ] | Point I &verbar; -I 1 | CH3 CH2CH2CH2CN CH3 120-122 2 ! CH3 CH2CH2CN CH3 3 , CH3 CH2CN CH3 4 CH3 CH2CH2CH2CH2CN CH3 S II 5 CH3 CH2CH2CH2CNH2 CH3 6 | CH3 CH2CH2CH2CN C2H5 CH3 CH3 CHCN CH3 8 CH3 CHCN CH3 I 9 CH3 t CHCN CH3 10 CH3 CH2CH2CH2CN CH2CH=CH2 11 CH3 CH2CH2CH2CN CH2C=-CH In the structure

both the oxime groups can exist in stereoisomeric forms E and Z, as illustrated for one oxime group in the structure below

This invention embraces all stereoisomers and mixtures thereof in all proportions.

The invention compounds may be prepared, for example, by the routes A and B (described below) which form another Route A Compounds of formula (I) can be prepared by reacting an acid chloride of formula (II) with a compound of formula (III) in a convenient solvent such as toluene, ethyl acetate, diethyl ether, methylene chloride, tetrahydrofuran (ThF) or dimethoxyethane (DME) at -50" to +100"C but preferably at 0 to 200C, in the presence of an acid binding agent such as a tertiary amine, for example, triethylamine or pyridine, or a metal carbonate such as potassium carbonate.

The product of formula (I) can be isolated by pouring the mixture into water, and extracting with a convenient organic solvent in the usual manner.

The acid chloride (11) can be produced by reacting the acid or its dry salt (IV)

with a reagent such as thionyl chloride or oxalyl chloride in a convenient solvent such as toluene, ether or chloroform containing a trace of L'MF.

The acid chloride (II), especially where R is methyl, can be purified by distillation.

The acid or its salt (lV) can be produced by hydrolysing the ester of formula (V)

(R3 is C1-10 alkyl) with an alkali metal hydroxide in a convenient solvent such as ethanol, methanol or water at 20 to 1000C.

The esters of formula (V) may be produced by alkylation of the known oxime of formula (VI)

The alkyl at ion may be performed by first treating the oxime (VI) with a base such as an alkali metal hydroxide (eg. sodium ethoxide), alkali metal carbonate (eg.

potassium carbonate) or a tertiary amine (eg.

triethylamine), but preferably with sodium hydroxide, in a suitable solvent such as water, an alkanol (eg. ethanol or methanol), a ketone (eg. methyl ethyl ketone or acetone), acetonitrile, dimethylformamide, tetrahydrofuran, or mixtures thereof, but preferably a mixture of water and methyl ethyl ketone. The oxime anion so generated is then treated with a halide hX, where R is as already defined and X is chlorine, bromine, iodine, or methane- or p-toluenesulphonate, or with a dialkylsulphate such as dimethylsulphate, at 0 to 200"C. The product (V) is isolated by extraction with a suitable solvent such as ethyl acetate, methylene chloride or diethyl ether and evaporating the solvent.The product, especially where R3 is ethyl and R is methyl can be purified by distillation at reduced pressure, or by crystallisation at -60" to 0 C, but especially at -45 to -30 C, from a suitable solvent such as a lower alkanol (eg. ethanol or methanol), to provide (V) as a solid.

The compound (III) can be prepared by reacting an acid chloride of formula (II) except that R is R2, with an amine R1SH2 (VII) in a convenient solvent such as toluene, ether or ethyl acetate at 00-100"C, in the presence of an acid binding agent such as triethylamine, pyridine or potassium carbonate. The reaction can also be carried out in a two phase system such as toluene and water where the amine component is not soluble in common organic solvents, in which case a solution of the acid chloride in a convenient solvent such as toluene or ethyl acetate is added to the amine in water containing an acid binding agent.

The product (III) can be isolated by pouring the mixture into water and extracting with a convenient organic solvent in the usual way.

When the amine (VII) is an a-amino nitrile that is not commercially available it may be prepared using the standard Strecker reaction conditions of reaction of an aldehyde with ammonium chloride and a metal cyanide, followed by additional treatment with ammonia gas in some cases. Other amino nitriles of general structure C(CH2)nH2, where n is 3-10, may be prepared, when not commercially available, by the standard Gabriel synthesis, using potassium phthalimide and a haloalkylcyanide, followed by cleavage of the cyanoalkyl phthalimide with hydrazine.

It will be appreciated that, where R and K2 are different, Route A may be carried out using compounds II and III in which the R and R2 are reversed.

Route B When the groups R and R2 are the same, the compound of formula (I) may also be prepared by reacting the amine (VII) with at least two chemical equivalents of the acid chloride (II)

in a convenient solvent as described in Route A at -50 to +100 but preferably at 0 to 200 in the presence of acid binding agent as described in Route A. Alternatively the reaction may also be carried out in a two phase system such as toluene and water, when the amine is not soluble in common organic solvents, in which case a solution of the acid chloride in a convenient solvent such as toluene or ethyl acetate is added to the amine in water containing an acid binding agent.The product (1) can be isolated by pouring the mixture into water and extracting with a convenient organic solvent in the usual manner.

The compounds of formula (I) and compositions containing them are active against fungal diseases, particularly fungal infections in plants, and especially against Plasmopara viticola (downy mildew on vines) and Phytophthora infestans (late blight on potatoes and tomatoes).

The compounds may be used directly for fungicidal purposes but are more conveniently formulated into compositions using a carrier or diluent. The invention thus provides a fungicidal composition comprising a compound of general formula (I) as hereinbefore defined, and a fungicidally acceptable carrier or diluent.

The invention also provides a method of combating fungi, which comprises applying to a plant, to a seed of a plant, or to the locus of the plant or seed, a compound as hereinbefore defined, or a composition containing the same.

The compounds, can be applied in a number of ways. For example they can be applied, formulated or unformulated, directly to the foliage of a plant, to seeds or to other medium in which plants are growing or are to be planted.

They can be sprayed on, dusted on or applied as a cream or paste formulation: or they can be applied as a vapour or as slow release granules. Application can be to any part of the plant including the foliage, stems, branches or roots, or to soil surrounding the roots, or to the seed before it is planted; or to the soil generally, to paddy water or to hydroponic culture systems. The invention compounds may also be injected into plants or sprayed onto vegetation using electrodynamic spraying techniques or other low volume methods.

The term "plant" as used herein includes seedlings, bushes and trees. Furthermore, the fungicidal method of the invention includes preventative, protectant, prophylactic and eradicant treatment.

The compounds are preferably used for agricultural and horticultural purposes in the form of a composition. The type of composition used in any instance will depend upon the particular purpose envisaged.

The compositions may be in the form of dustable powders or granules comprising the active ingredient (invention compound) and a solid diluent or carrier, for example fillers such as kaolin, bentonite, kieselguhr, dolomite, calcium carbonate, talc, powdered magnesia, Fuller's earth, gypsum, diatomaceous earth and China clay.

Such granules can be preformed granules suitable for application to the soil without further treatment. These granules can be made either by impregnating pellets of filler with the active ingredient or by pelleting a mixture of the active ingredient and powdered filler.

Compositions for dressing seed may include an agent (for example a mineral oil) for assisting the adhesion of the composition to the seed; alternatively the active ingredient can be formulated for seed dressing purposes using an organic solvent (for example N-methylpyrrolidone, propylene glycol or dimethylformamide). The compositions may also be in the form of wettable powders or water dispersible granules comprising wetting or dispersing agents to facilitate their dispersion in liquids. The powders and granules may also contain fillers and suspending agents.

Emulsifiable concentrates or emulsions may be prepared by dissolving the active ingredient in an organic solvent optionally containing a wetting or emulsifying agent and then adding the mixture to water which may also contain a wetting or emulsifying agent. Suitable organic solvents are aromatic solvents such as alkylbenzenes and alkylnaphthalenes, ketones such as isophorone, cyclohexanone and methylcyclohexanone, chlorinated hydrocarbons such as chlorobenzene and trichlorethane, and alcohols such as furfuryl alcohol, butanol and glycol ethers.

Suspension concentrates of largely insoluble solids may be prepared by ball or bead milling with a dispersing agent and including a suspending agent to stop the solid settling.

Compositions to be used as sprays may be in the form of aerosols wherein the formulation is held in a container under pressure in the presence of a propellant, eg.

fluorotrichloromethane or dichlorodifluoromethane.

The invention compounds can be mixed in the dry state with a pyrotechnic mixture to form a composition suitable for generating in enclosed spaces a smoke containing the compounds.

Alternatively, the compounds may be used in a microencapsulated form. They may also be formulated in biodegradable polymeric formulations to obtain a slow, controlled release of the active substance.

By including suitable additives, for example additives for improving the distribution, adhesive power and resistance to rain on treated surfaces, the different compositions can be better adapted for various utilities.

The invention compounds can be used as mixtures with fertilisers (eg. nitrogen-, potassium- or phosphoruscontaining fertilisers). Compositions comprising only granules of fertiliser incorporating, for example coated with, the compound are preferred. Such granules suitably contain up to 25% by weight of the compound. The invention therefore also provides a fertiliser composition comprising a fertiliser and the compound of general formula (I) or a salt or metal complex thereof.

Wettable powders, emulsifiable concentrates and suspension concentrates will normally contain surfactants eg. a wetting agent, dispersing agent, emulsifying agent or suspending agent. These agents can be cationic, anionic or non-ionic agents.

Suitable cationic agents are quaternary ammonium compounds, for example cetyltrimethylammonium bromide.

Suitable anionic agents are soaps, salts of aliphatic monoesters of sulphuric acid (for example sodium lauryl sulphate), and salts of sulphonated aromatic compounds (for example sodium dodecylbenzenesulphonate, sodium, calcium or ammonium lignosulphonate, butylnaphthalene sulphonate, and a mixture of sodium diisopropyl- and triisopropyl naphthalene sulphonates).

Suitable non-ionic agents are the condensation products of ethylene oxide with fatty alcohols such as oleyl or cetyl alcohol, or with alkyl phenols such as octyl- or nonyl-phenol and octylcresol. Other non-ionic agents are the partial esters derived from long chain fatty acids and hexitol anhydrides, the condensation products of the said partial esters with ethylene oxide, and the lecithins. Suitable suspending agents are hydrophilic colloids (for example polyvinylpyrrolidone and sodium carboxymethylcellulose), and swelling clays such as bentonite or attapulgite.

Compositions for use as aqueous dispersions or emulsions are generally supplied in the form of a concentrate containing a high proportion of the active ingredient, the concentrate being diluted with water before use. These concentrates should preferably be able to withstand storage for prolonged periods and after such storage be capable of dilution with water in order to form aqueous preparations which remain homogeneous for a sufficient time to enable them to be applied by conventional spray equipment. The concentrates may conveniently contain up to 958, suitably 10-85%, for example 25-60%, by weight of the active ingredient.

After dilution to form aqueous preparations, such preparations may contain varying amounts of the active ingredient depending upon the intended purpose, but an aqueous preparation containing 0.0005% or 0.01% to 108 by weight of active ingredient may be used.

The compositions of this invention may contain other compounds having biological activity, eg. compounds having similar or complementary fungicidal activity or which possess plant growth regulating or insecticidal activity.

A fungicidal compound which may be present in the composition of the invention may be one which is capable of combating ear diseases of cereals (eg. wheat) such as Septoria, Gibberella and Helminthosporium spp., seed and soil borne diseases and downy and powdery mildews on grapes and powdery mildew and scab on apple etc. By including another fungicide the composition can have a broader spectrum of activity than the compound of general formula (I) alone. Further the other fungicide may have a synergistic effect on the fungicidal activity of the compound of general formula (I).Examples of fungicidal compounds which may be included in the composition of the invention are carbendazim, benomyl, thiophanate-methyl, thiabendazole, fuberidazole, etridazole, dichlofluanid, cymoxanil, oxadixyl, ofurace, metalaxyl, furalaxyl, benalaxyl, fosetyl aluminium, fenarimol, iprodione, procymidone, vinclozolin, penconazole, myclobutanil, R0151297, S3308, pyrazophos, ethirimol, ditalimfos, tridemorph, triforine, nuarimol, triazbutyl, guazatine, propiconazole, prochloraz, flutriafol, hexaconazole ie. the chemical l-(1,2,4-triazol-l-yl)-2-(2,4-dichlorophenyl)- hexan-2-ol, DPX H6573(1-(bis-4fluorophenyl)methylsilyl)methyl)-lH-1,2,4-triazole, triadimefon, triadimenol, diclobutrazol, fenpropimorph, fenpropidine, chlorozolinate, diniconazol, imazalil, fenfuram, carboxin, oxycarboxin, methfuroxam, dodemorph, BAS 454, blasticidin S, Kasugamycin, edifenphos, kitazin P, cycloheximide, phthalide, probenazole, isoprothiolane, tricyclazole, pyroquilan, chlorbenzthiazone, neoasozin, polyoxin D, validamycin A, repronil, flutolanil, pencycuron, diclomezine, phenazin oxide, nickel dimethyldithiocarbamate, techlofthalam, bitertanol, bupirimate, etaconazole, streptomycin, cypofuram, biloxazol, quinomethionate, dimethirimol, l-(2-cyano-2methoxyiminoacetyl)-3-ethyl urea, fenapanil, tolclofosmethyl, pyroxyfur, polyram, maneb, mancozeb, captafol, chlorothalonil, anilazine, thiram, captan, folpet, zineb, propineb, sulphur, dinocap, binapacryl, nitrothalisopropyl, dodine, dithianon, fentin hydroxide, fentin acetate, tecnazene, quintozene, dichloran, copper containing compounds such as copper oxychloride, copper sulphate and Bordeaux mixture, and organomercury compounds.

The compounds of general formula (I) can be mixed with soil, peat or other rooting media for the protection of plants against seed-borne, soil-borne or foliar fungal diseases.

Suitable insecticides which may be incorporated in the composition of the invention include pirimicarb, dimethoate, demeton-s-methyl, formothion, carbaryl, isoprocarb, XMC, BPMC, carbofuran, carbosulfan, diazinon, fenthion, fenitrothion, phenthoate, chlorpyrifos,isoxathion, propaphos, monocrotophas, buprofezin, ethroproxyfen and cycloprothrin.

Plant growth regulating compounds are compounds which control weeds or seedhead formation, or selectively control the growth of less desirable plants (eg. grasses).

Examples of suitable plant growth regulating compounds for use with the invention compounds are the gibberellins (eg. GA3, GA4 or GA7), the auxins (eg.

indoleacetic acid, indolebutyric acid, naphthoxyacetic acid or naphthylacetic acid), the cytokinins (eg. kinetin, diphenylurea, benzimidazole, benzyladenine or benzylaminopurine), phenoxyacetic acids (eg. 2,4-D or MCEA), substituted benzoic acids (eg. triiodobenzoic acid), morphactins (eg. chlorfluoroecol), maleic hydrazide, glyphosate, glyphosine, long chain fatty alcohols and acids, dikegulac, paclobutrazol, flurprimidol, fluoridamid, mefluidide, substituted quaternary ammonium and phosphonium compounds (eg.

chloromequat chlorphonium or mepiquatchloride), ethephon, carbetamide, methyl-3,6-dichloroanisate, daminozide, asulam, abscisic acid, isopyrimol, 1-(4-chlorophenyl)-4,6 dimethyl-2-oxo-l, 2-dihydropyridine-3-carboxylic acid, hydroxybenzonitriles (eg. bromoxynil), difenzoquat, benzoylprop-ethyl 3,6-dichloropicolinic acid, fenpentezol, inabenfide, triapenthenol and tecnazene.

The following are Examples of compositions suitable for agricultural and horticultural purposes which can be formulated from the compounds of the invention. Such compositions form another aspect of the invention.

Temperatures are given in degrees centigrade ("C), and percentages are by weight. In all of the Examples Compound No. 1 of Table I is the compound used.

EXAMPLE 1 An emulsifiable concentrate is made up by mixing the ingredients, and stirring the mixture until all the constituents are dissolved.

Compound 10% Isophorone 25% Calcium dodecylbenzenesulphonate 5% Nonylphenolethoxylate (13 moles ethylene oxide) 10% Alkyl benzenes 50% EXAMPLE 2 The active ingredient is dissolved in methylene dichloride and the resultant liquid sprayed onto the granules of attapulgite clay. The solvent is then allowed to evaporate to produce a granular composition.

Compound 5% Attapulgite granules 95% EXAMPLE 3 A composition suitable for use as a seed dressing is prepared by grinding and mixing the three ingredients.

Compound 50% Mineral oil 2% China clay 48% EXAMPLE 4 A dustable powder is prepared by grinding and mixing the active ingredient with talc.

Compound 5% Talc 95% EXAMPLE 5 A suspension concentrate is prepared by ball milling the ingredients to form an aqueous suspension of the mixture with water.

Compound 40% Sodium lignosulphonate 10% Bentonite clay 1% Water 49% This formulation can be used as a spray by diluting into water or applied directly to seed.

EXAMPLE 6 A wettable powder formulation is made by mixing and grinding the ingredients.

Compound 258 Sodium lauryl sulphate 2% Sodium lignosulphonate 5% Silica 25% China clay 43% EXAMPLE 7 Compound 1 of Table I was tested against a variety of fungal diseases of plants. The technique employed was as follows.

The plants were grown in John Innes Potting Compost (No 1 or 2) in 4 cm diameter minipots. The test compound was formulated by bead milling with aqueous Dispersol T which was diluted to the required concentration immediately before use. The formulation (100 ppm active ingredient) was sprayed on to the foliage and applied to the roots of the plants in the soil. The sprays were applied to maximum retention and the root drenches to a final concentration equivalent to approximately 40 ppm a.i./dry soil. Tween 20, to give a final concentration of 0.05%, was added when the sprays were applied to cereals.

For most of the tests the formulation was applied to the soil (roots) and to the foliage (by spraying) one or two days before the plant was inoculated with the disease.

Exceptions were (i) was the test on Erysiphe graminis in which the plants were inoculated 24 hours before treatment and (ii) the tests on Phytophthora infestans in which the formulation was applied in separate tests to (a) the soil and (b) the foliage. Foliar pathogens were applied by spray as spore suspensions onto the leaves of test plants.

After inoculation, the plants were put into an appropriate environment to allow infection to proceed and then incubated until the disease was ready for assessment. The period between inoculation and assessment varied from four to fourteen days according to the disease and environment.

The disease control was recorded by the following grading: 4 = no disease 3 = trace - 5% of disease on untreated plants 2 = 6-25% of disease on untreated plants 1 = 26-59% of disease on untreated plants 0 = 60-100% of disease on untreated plants The results are shown in Table II.

TABLE II

COMPOUND PUCCINIA ERYSIPHE VENTURIA PYRICULARIA CERCOSPORA PLASMOPARA PHYTOPHTHORA NO. RECONDITA GRAMINIS INAEQUALIS ORYZAE ARACHIDICOLA VITICOLA INFESTANS (WHEAT) HORDEI (APPLE) (RICE) (PEANUT) (VINE) (TOMATO) (BARLEY) FOLIAR SOIL APPLICATION APPLICATION 1 # # # # # 4 3 4

Claims (10)

1. What we claim is 1. Compounds having the general formula (I)

   in which R and R2 are independently alkyl, cycloalkyl, cycloalkylalkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted benzyl or a metal ion; and R1 is alkyl substituted by cyano or thiocarbamoyl, the alkyl group being optionally substituted, in addition, by optionally substituted aryl or optionally substituted heterocyclyl.
2. 2. Compounds as claimed in claim 1 wherein R or R2 is an alkyl group containing from 1-4 carbon atoms or is allyl or propargyl.
3. 3. Compounds as claimed in claim 2 wherein R or R2 is methyl.
4. 4. Compounds as claimed in any of claims 1 to 3 wherein K1 is alkyl substituted by cyano or thiocarbamoyl in which the alkyl group contains from 1 to 10 carbon atoms in straight or branched chains, and, optionally, is additionally substituted by (i) aryl (eg. phenyl) optionally substituted by, for example, C14 alkyl (eg. methyl), halogen (eg. chlorine, fluorine, bromine or iodine), C1.4 alkoxy (eg. methoxy), nitro, haloalkyl (eg. trifluoromethyl), or cyano, or (ii) heterocyclyl (eg. 2-furyl, 2-thienyl) optionally substituted by, for example, C1-4 alkyl (eg. methyl), halogen (eg. chlorine or bromine), nitro, haloalkyl (eg. trifluoromethyl) or cyano.
5. 5. Compounds having the general formula (I)

   in which R and K2 are independently C14 alkyl, C3-5 alkenyl or C3-5 alkynyl and R1 is cyanoalkyl in which the alkyl group contains from 1 to 6 carbon atoms and is optionally substituted by C1-4 alkyl, phenyl, or heterocyclyl, or R1 is C16 alkyl substituted by thiocarbamoyl.
6. 6. Compounds as claimed in any of the preceding claims wherein both R and R2 are methyl and R1 is cyano (C2-4) alkyl.
7. 7. A process for preparing compounds as claimed in any of claims 1 to 6 which comprises reacting an acid chloride of formula

   with a compound of formula

   in a convenient solvent such as toluene, ethyl acetate, diethyl ether, methylene chloride, tetrahydrofuran (THF) or dimethoxyethane (DME) at -500 to +1000C but preferably at 0 to 200C, in the presence of an acid binding agent such as a tertiary amine, for example, triethylamine or pyridine, or a metal carbonate such as potassium carbonate, the product being isolated, if necessary, by pouring the mixture into water, and extracting with a convenient organic solvent in the usual manner.
8. 8. A process for preparing compounds as claimed in any of claims 1 to 6 and wherein the groups R and R2 are the same, which comprises either (a) reacting the amine R1NH2 with at least two chemical equivalents of the acid chloride of formula

   in a solvent as defined in claim 7 at -500 to +1000C, but preferably at 0 to 200C in the presence of acid binding agent as defined in claim 7, or (b) carrying out the reaction in a two phase system such as toluene and water, when the amine is not soluble in common organic solvents, in which case a solution of the acid chloride in a convenient solvent such as toluene or ethyl acetate is added to the amine in water containing an acid binding agent; thereafter, if necessary, isolating the product by pouring the mixture into water and extracting with an organic solvent.
9. 9. A fungicidal composition comprising a compound of general formula (I) as defined in any of claims 1 to 6, and a carrier or diluent therefor.
10. 10. A method of combating fungi, which comprises applying to a plant, to a seed of a plant, or to the locus of the plant or seed, a compound as defined in any of claims 1 to 6 or a composition as defined in claim 7.