GB2230776A - N-Substituted thiazole-5-carboximidate and -thiocarboximidate derivatives - Google Patents

Abstract

The invention provides thiazole imine derivatives of the general formula:- @ or acid-addition salts or metal salts complexes thereof, in which R represents an optionally substituted alkyl or phenyl group; R<1> represents an optionally substituted alkyl, alkenyl, alkynyl or benzyl group; R<2> represents a hydrogen or halogen atom or an alkyl, haloalkyl, alkoxy, haloalkoxy, alkylthio, hydroxyl, cyano, nitro, amino, alkylamino or dialkylamino group; and represents an oxygen or sulphur atom; processes for their preparation; compositions containing such compounds and their use as fungicides.

Description

THIAZOLE IMINE DERIVATIVES This invention relates to certain thiazole imine derivatives, a process for their preparation, compositions containing such compounds and their use as fungicides.

DE-A-1 953 954 discloses anthelmintic compounds of the general formula

in which X represents a hydrogen atom, a C1 8alkyl or isoalkyl group, a (CH2)nOR group (where n = 2 to 8 and R is a C1 8n-alkyl or isoalkyl group), a branched mono- or polyhydroxyalkyl moiety, an optionally substituted benzyl group, a pyridine moiety of formula

wherein R1 to R4 represent a hydrogen atom or a C1-5alkyl group and n = O to 2, or an aromatic moiety of the formula

wherein R1' to R5' represent hydrogen, halogen, NO2-, OH-, Y-, OY- or COY- and Y represents CH3 - or alkyl up to C6Hl3. However, there is no indication that these compounds have any fungicidal activity.

According to the present invention there is provided a compound of the general formula

or an acid-addition salt or metal salt complex thereof, in which R represents an optionally substituted alkyl or phenyl group; Rl represents an optionally substituted alkyl, alkenyl, alkynyl or benzyl group; R2 represents a hydrogen or halogen atom or an alkyl, haloalkyl, alkoxy, haloalkoxy, alkylthio, hydroxyl, cyano, nitro, amino, alkylamino or dialkylamino group; and X represents an oxygen or sulphur atom.

When the compounds of this invention contain an alkyl, alkenyl or alkynyl substituent group, this may be linear or branched and may contain up to 12, preferably up to 6, carbon atoms.

When any of the foregoing substituents are designated as being optionally substituted, the substituent groups which are optionally present may be any one or more of those customarily employed in the development of pesticidal compounds, and/or the modification of such compounds to influence their structure/ activity, persistence, penetration or other property. Specific examples of such substituents include, for example, halogen atoms, nitro, cyano, hydroxyl, alkyl, haloalkyl, alkoxy, haloalkoxy, amino, alkylamino, dialkylamino, formyl, alkoxycarbonyl, carboxyl, alkanoyl, alkylthio, alkylsulphinyl, alkylsulphonyl, carbamoyl and alkylamido groups. When any of the foregoing substituents represents or contains an alkyl substituent group, this may be linear or branched and may contain up to 12, preferably up to 6, and especially up to 4, carbon atoms.

It is preferred that R is an unsubstituted 1-4 alkyl group or, more preferably, a phenyl group substituted by 1 to 3 halogen, especially chlorine, atoms.

Preferably, R1 represents a C1-12 alkyl, particularly a C16 alkyl, group, a C2~12 alkenyl, particularly a C 2-6 alkenyl and especially a C24 alkenyl, group, a C2 12alkynyl, particularly a C2 6alkynyl and especially a C alkynyl, group, or a 2-4 benzyl group, each group being optionally substituted by one or more substituents selected from halogen atoms, nitro, cyano, hydroxyl, C14 haloalkyl, C14 alkoxy, C1 4 haloalkoxy, amino, C14 alkylamino, di-Cl 4 alkylamino, formyl, C1-4 alkoxycarbonyl and carboxyl groups.

A particularly preferred sub-group of compounds of formula I is that in which R represents a propyl or dichlorophenyl group; R1 represents a methyl, ethyl, propyl, butyl, pentyl, hexyl, allyl, propynyl or dichlorobenzyl group; and R2 represents a hydrogen atom.

It should also be appreciated that the compounds of formula I are capable of existing as different geometric isomers. The invention thus includes both the individual isomers and mixtures of such isomers.

The present invention also provides a process for the preparation of a compound of formula I as defined above or an acid-addition salt or metal salt complex thereof which comprises reacting a compound of the general formula

in which R and R2 are as defined above and L is a leaving group, with a compound of the general formula H-X-R1 (III) in which Rl and X are as defined above, in the presence of a base, and, if desired, reacting the compound of formula I so obtained with a suitable acid or metal salt to form an acid-addition salt or metal salt complex thereof.

Preferably, the leaving group L is a chlorine or bromine atom.

In some cases, for instance when X represents an oxygen or sulphur atom, the compound of formula III may advantageously be treated with the base prior to admixture with the compound of formula II. Thus, for example, when the compound of formula III is an alkanol, the mixture of the compound of formula III with base may be achieved by dissolving sodium metal in the alkanol or by reaction of the alkanol with sodium hydride. In cases where X represents a sulphur atom, the base may conveniently be a base such as pyridine or sodium hydride.

The above process may be carried out in the absence of an additional, inert solvent, for instance, when the compound of formula III is in excess and the excess acts as a solvent, or in cases when, for instance, pyridine is used as the base and itself acts as a solvent. Alternatively, an additional, inert solvent may be present. Suitable solvents include 1,2-dimethoxyethane, dimethylsulphoxide, N,N-dimethylformamide and tetrahydrofuran and, of these, tetrahydrofuran is particularly preferred. The reaction is suitably carried out at a temperature from -80 C to 1000C, the preferred reaction temperature being 15iC to 70it.

Compounds of formula II, in which L represents a chlorine or bromine atom can be prepared by reacting a compound of the general formula

in which R and R2 are as defined above, with a halogenating agent. Suitable halogenating agents include thionyl chloride, phosphorous pentachloride, phosphorous trichloride and phosphorous tribromide.

The reaction may be carried out in an excess of the halogenating agent as solvent or in the presence of an inert solvent such as diethyl ether or tetrahydrofuran.

Compounds of formula IV in which R2 represents a chlorine atom may conveniently be prepared by reacting 2-chlorothiazole with a compound of the general formula

where R is as defined above, preferably in the presence of a suitable base, such as butyl lithium.

The resulting compounds may then be converted into other compounds of formula IV in which R2 does not represent a chlorine atom by means of conventional reactions. For instance, compounds of formula IV in which R2 represents a hydrogen atom may be prepared by reacting compounds of formula IV in which R2 represents a chlorine atom with a suitable reducing agent, such as zinc in acetic acid.

2-chlorothiazole may be prepared from 2-aminothiazole (a known compound) using the procedure of K. Ganapathi and A. Venkataraman, Proc.

Indian Acad. Sci., 1945, 22A, 343, 362. The compounds of formula V are all known compounds and may be prepared according to processes described in a review of the industrial preparation of isocyanates by Twitchett, Chem. Soc. Rev, 1974, 3, 209.

Alternatively, compounds of formula IV may be prepared by reacting a compound of the general formula

where R2 is as defined above, with a compound of the general formula 2 (VII) where R is as defined above, in the presence of a suitable base, such as pyridine.

Compounds of formula VI may be prepared by reacting a compound of the general formula

where R2 is as defined above, with a chlorinating agent, such as thionyl chloride.

Compounds of formula VIII may conveniently be prepared by treating a compound of the general formula

in which R2 is as defined above and R3 represents an alkyl group, with an acid or base.

Compounds of formula IX in which R2 is other than alkyl may be prepared by the deamination of the corresponding alkyl-2-aminothiazole-5-carboxylate, the latter being prepared by the method of E. Campaigne and W.L. Archer, J.A.C.S., 1952, 74, 5799. Compounds of formula IX in which R2 is alkyl may be prepared according to the method of A. Silberg, A. Benko and G. Csavassy, Ber., 97(6), 1684-7, 1964.

Compounds of formula III and VII are either known compounds or can be prepared by processes analogous to known processes.

The compounds of general formula I have been found to have fungicidal activity. Accordingly, the invention further provides a fungicidal composition which comprises a carrier and, as active ingredient, a compound of formula I or an acid-addition salt or metal salt complex thereof as defined above. A method of making such a composition is also provided which comprises bringing a compound of formula I as defined above, or an acid-addition salt or metal salt complex thereof, into association with at least one carrier. Such a composition may contain a single compound or a mixture of several compounds of the present invention. It is also envisaged that different isomers or mixtures of isomers may have different levels or spectra of activity and thus compositions may comprise individual isomers or mixtures of isomers.

A composition according to the invention preferably contains from 0.5 to 95% by weight of active ingredient.

A carrier in a composition according to the invention is any material with which the active ingredient is formulated to facilitate application to the locus to be treated, which may for example be a plant, seed or soil, or to facilitate storage, transport or handling. A carrier may be a solid or a liquid, including a material which is normally gaseous but which has been compressed to form a liquid, and any of the carriers normally used in formulating fungicidal compositions may be used.

Suitable solid carriers include natural and synthetic clays and silicates, for example natural silicas such as diatomaceous earths; magnesium silicates, for example talcs; magnesium aluminium silicates, for example attapulgites and vermiculites; aluminium silicates, for example kaolinites, montmorillonites and micas; calcium carbonate calcium sulphate; ammonium sulphate; synthetic hydrated silicon oxides and synthetic calcium or aluminium silicates; elements, for example carbon and sulphur; natural and synthetic resins, for example coumarone resins, polyvinyl chloride, and styrene polymers and copolymers; solid polychlorophenols; bitumen; waxes, for example beeswax, paraffin wax, and chlorinated mineral waxes; and solid fertilisers, for example superphosphates.

Suitable liquid carriers include water; alcohols, for example isopropanol and glycols; ketones, for example acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ethers; aromatic or araliphatic hydrocarbons, for example benzene, toluene and xylene; petroleum fractions, for example, kerosine and light mineral oils; chlorinated hydrocarbons, for example carbon tetrachloride, perchloroethylene and trichloroethane. Mixtures of different liquids are often suitable.

Fungicidal compositions are often formulated and transported in a concentrated form which is subsequently diluted by the user before application.

The presence of small amounts of a carrier which is a surface-active agent facilitates this process of dilution. Thus preferably at least one carrier in a composition according to the invention is a surface-active agent. For example the composition may contain at least two carriers, at least one of which is a surface-active agent.

A surface-active agent may be an emulsifying agent, a dispersing agent or a wetting agent; it may be nonionic or ionic. Examples of suitable surface-active agents include the sodium or calcium salts of polyacrylic acids and lignin sulphonic acids; the condensation products of fatty acids or aliphatic amines or amides containing at least 12 carbon atoms in the molecule with ethylene oxide and/or propylene oxide; fatty acid esters of glycerol, sorbitol, sucrose or pentaerythritol; condensates of these with ethylene oxide and/or propylene oxide; condensation products of fatty alcohol or alkyl phenols, for example -octylphenol or p-octylcresol, with ethylene oxide and/or propylene oxide; sulphates or sulphonates of these condensation products; alkali or alkaline earth metal salts, preferably sodium salts, of sulphuric or sulphonic acid esters containing at least 10 carbon atoms in the molecule, for example sodium lauryl sulphate, sodium secondary alkyl sulphates, sodium salts of sulphonated castor oil, and sodium alkylaryl sulphonates such as dodecylbenzene sulphonate; and polymers of ethylene oxide and copolymers of ethylene oxide and propylene oxide.

The compositions of the invention may for example be formulated as wettable powders, dusts, granules, solutions, emulsifiable concentrates, emulsions, suspension concentrates and aerosols.

Wettable powders usually contain 25, 50 or 75% w of active ingredient and usually contain in addition to solid inert carrier, 3-10% w of a dispersing agent and, where necessary, 0-10% w of stabiliser(s) and/or other additives such as penetrants or stickers.

Dusts are usually formulated as a dust concentrate having a similar composition to that of a wettable powder but without a dispersant, and may be diluted in the field with further solid carrier to give a composition usually containing i-10% w of active ingredient. Granules are usually prepared to have a size between 10 and 100 BS mesh (1.676 - 0.152 mm), and may be manufactured by agglomeration or impregnation techniques. Generally, granules will contain i-75% w active ingredient and 0-10% w of additives such as stabilisers, surfactants, slow reiease modifiers and binding agents. The so-called "dry flowable powders" consist of relatively small granules having a relatively high concentration of active ingredient. Emulsifiable concentrates usually contain, in addition to a solvent and, when necessary, co-solvent, 1-50% w/v active ingredient, 2-20% w/v emulsifiers and 0-20% w/v of other additives such as stabilisers, penetrants and corrosion inhibitors. Suspension concentrates are usually compounded so as to obtain a stable, non-sedimenting flowable product and usually contain 10-75% w active ingredient, 0.5-15% w of dispersing agents, 0.1-10% w of suspending agents such as protective colloids and thixotropic agents, 0-10% w of other additives such as defoamers, corrosion inhibitors, stabilisers, penetrants and stickers, and water or an organic liquid in which the active ingredient is substantially insoluble; certain organic solids or inorganic salts may be present dissolved in the formulation to assist in preventing sedimentation or as anti-freeze agents for water.

Aqueous dispersions and emulsions, for example compositions obtained by diluting a wettable powder or a concentrate according to the invention with water, also lie within the scope of the invention.

The said emulsions may be of the water-in-oil or of the oil-in-water type, and may have a thick 'mayonnaise' like consistency.

The composition of the invention may also contain other ingredients, for example other compounds possessing herbicidal, insecticidal or fungicidal properties.

Of particular interest in enhancing the duration of the protective activity of the compounds of this invention is the use of a carrier which will provide a slow release of the fungicidal compounds into the environment of the plant which is to be protected.

Such slow-release formulations could, for example, be inserted in the soil adjacent to the roots of a vine plant, or could include an adhesive component enabling them to be applied directly to the stem of a vine plant.

The invention still further provides the use as a fungicide of a compound of the general formula I as defined above or an acid-addition salt or metal salt complex thereof or a composition as defined above, and a method for combating fungus at a locus, which comprises treating the locus, which may be for example plants subject to or subjected to fungal attack, seeds of such plants or the medium in which such plants are growing or are to be grown, with such a compound or composition.

The present invention is of wide applicability in the protection of crop plants against fungal attack. Typical crops which may be protected include vines, grain crops such as wheat and barley and rice.

The duration of protection is normally dependent on the individual compound selected, and also a variety of external factors, such as climate, whose impact is normally mitigated by the use of a suitable formulation.

The invention is further illustrated by the following examples.

Example 1 Preparation of pent-3-yl-N- (2 ,4-dichlorophenyl) thiazole-5-carboximidate (R=2,4-dichlorophenyl; R1=pent-3-yl; R2=hydrogen; X=oxygen) (i) Preparation of N- (2 ,4-dichlorophenyl) 2-chlorothiazole-5-carboxamide Butyl lithium (2.4M, 17.4ml) in hexane was added slowly to a solution of 2-chlorothiazole (4.8g, 40 mmol) in tetrahydrofuran (100 ml) at -78iC under an atmosphere of nitrogen. After stirring the reaction mixture for 10 minutes, a solution of 2,4-dichlorophenyl isocyanate (7.8g, 44 mmol) in tetrahydrofuran (50 ml) was added. After an hour, water (100 ml) was added and the tetrahydrofuran was then evaporated under reduced pressure.The aqueous residue was extracted with ethyl acetate (2 x 250 ml) and the combined organic extract was then washed with saturated sodium chloride solution (50 ml) and dried.

Evaporation of the solvent gave a pale yellow solid which on recrystallisation from ethyl acetatepetroleum ether yielded N-(2,4-dichlorophenyl) 2-chlorothiazole-5-carboxamide (11.2g) as a solid, m.pt. 1500C.

Analysis Calc: C: 39.1; H: 1.6; N: 9.1t Found: C: 39.6; H: 1.6; N: 9.1% (ii) Preparation of N- (2, 4-dichlorophenyl) thiazole-5-carboxamide Zinc dust (5.0g) was added to a solution of the N- (2, 4-dichlorophenyl) 2-chlorothiazole-5-carboxamide (11.2g) obtained in (i) in acetic acid (100 ml) at 120 C. The resultant mixture was refluxed for 1 hour, cooled, made basic with ammonium hydroxide solution and then extracted into ethyl acetate (2 x 300 ml). The combined organic extract was then washed with brine (50 ml) and dried. Evaporation of the solvent left a solid which on recrystallisation from ethyl acetate-petroleum ether gave N- (2, 4-dichlorophenyl) thiazole-5-carboxamide (7.8g) as a white solid, m.pt. 1300C.

Analysis Calc: C: 43.8; H: 2.2; N: 10.3% Found: C: 43.8; H: 2.3; N: 10.5% (iii) Preparation of pent-3-yl-N- (2 ,4-dichlorophenyl) thiazole-5-carboximidate A solution of N- (2, 4-dichlorophenyl) thiazole-5- carboxamide (0.8g, 3 mmol) obtained in (ii) in thionyl chloride (50 ml) was refluxed for 7 hours under an atmosphere of nitrogen. The excess thionyl chloride was then removed under reduced pressure and the residue was dissolved in tetrahydrofuran (40 ml).

Sodium 3-pentoxide was prepared by dissolving sodium in pentan-3-ol. A solution of sodium 3-pentoxide (10 mmol) in tetrahydrofuran (50 ml) was added to the reaction mixture and, after 40 minutes, the solvent was evaporated. 1:3 water:ethyl acetate (400 ml) was added to the residue and the organic layer was then washed with saturated sodium chloride solution (50 ml) and dried. Evaporation of the solvent gave an oil and flash chromatography of this oil on a silica gel column using diethyl ether-petroleum ether as eluant gave pent-3-yl-N-(2,4-dichlorophenyl) thiazole-5-carboximidate (0.8lug) as a yellow oil.

M found: 342.0359.

Examples 2 to 12 By processes similar to those described in Example 1 above, further compounds according to the present invention were prepared as detailed in Table I below. In this table, the compounds are identified by reference to formula I. Melting point, high resolution mass spectroscopy and C,H,N analysis data for the compounds of Examples 2 to 12 is given inTable IA below.

TABLE I Example No. R R1 R2 X 2 2,4-dichlorophenyl -CH3 -H O 3 2,4-dichlorophenyl -C2H5 -H O 4 2,4-dichlorophenyl -CH(CH3)2 -H O 5 2,4-dichlorophenyl -CH(CH3)(C2H5) -H O 6 2,4-dichlorophenyl -CH2CH(CH3)2 -H O 7 2,4-dichlorophenyl -CH(C2H5)CH2CH2CH3 -H O 8 2,4-dichlorophenyl -CH(C2H5)CH(CH3)2 -H O 9 2,4-dichlorophenyl -CH2-CH=CH2 -H O 10 2,4-dichlorophenyl -CH2-C=CH -H O 11 2,4-dichlorophenyl -CH2CH2CH3 -H S 12 -CH2CH2CH3 2,4-dichlorophenyl -H O TABLE IA Example M.pt. M+ Analysis (%) No. C Found C H N Calc Found Calc Found Calc Found 2 285.9735 3 299.9896 4 314.0047 5 328.0201 6 328.0204 7 356.0523 8 356.0520 9 311.9889 10 309.9730 11 329.9818 12 66-68 51.1 51.6 4.3 4.3 8.5 8.7 Example 13 The fungicidal activity of compounds of the invention was investigated by means of the following tests.

(a) Antisporulant activity against vine downy mildew (Plasmopara viticola; Pva) The test is a direct antisporulant one using a foliar spray. The lower surfaces of leaves of whole vine plants (cv Cabernet Sauvignon) are inoculated by spraying with an aqueous suspension containing 104 zoosporangia/ml 2 days prior to treatment with the test compound. The inoculated plants are kept for 24 hours in a high humidity compartment, then 24 hours at glasshouse ambient temperature and humidity. Infected leaves are sprayed on their lower surfaces with a solution of active material in 1:1 water/acetone containing 0.04% "TWEEN 20" (Trade Mark; a polyoxyethylene sorbitan ester surfactant). The spraying is carried out with a moving track sprayer giving an application rate of lkg/ha.

After spraying, the plants are returned to normal glasshouse conditions for 96 hours and are then transferred to the high humidity compartment for 24 hours to induce sporulation, prior to assessment. Assessment is based on the percentage of the leaf area covered by sporulation compared with that on control leaves.

(b) Direct protectant activity against vine downy mildew (Plasmopara viticola; Pvp) The test is a direct protectant one using a foliar spray. The lower surfaces of leaves of whole vine plants (cv Cabernet Sauvignon) are sprayed with the test compound at a dosage of 1 kilogram of active material per hectare using a track sprayer as described under (a), and after a subsequent 24 hours under normal glasshouse conditions the lower surfaces of the leaves are inoculated by spraying with an aqueous solution containing 104 zoosporangia/ml. The inoculated plants are kept for 24 hours in a high humidity compartment, 5 days under normal glasshouse conditions and then returned for a further 24 hours to high humidity. Assessment is based on the percentage of leaf area covered by sporulation compared with that on control leaves.

(c) Activity against wheat leafspot (Leptosphaeria nodorum; Ln.) The test is a direct therapeutic one, using a foliar spray. Leaves of wheat plants (cv Nardler), at the single leaf stage, are inoculated by spraying with an aqueous suspension containing 1 x 106 spores/ml. The inoculated plants are kept for 24 hours in a high humidity compartment prior to treatment.

The plants are sprayed with a solution of the test compound at a dosage of 1 kilogram of active material per hectare using a track sprayer as described under (a). After drying, the plants are kept for 6-8 days at 20-25 C and moderate humidity, followed by assessment.

Assessment is based on the density of lesions per leaf compared with that on leaves of control plants.

(d) Activity against barley powdery mildew (ErYsiphe graminis f.sp. horde; Eg) The test is a direct therapeutic one, using a foliar spray. Leaves of barley seedlings, (cv. Golden Promise) are inoculated by dusting with mildew conidia one day prior to treatment with the test compound. The inoculated plants are kept overnight at glasshouse ambient temperature and humidity prior to treatment.

The plants are sprayed with the test compound at a dosage of 1 kilogram of active material per hectare using a track sprayer as described under (a). After drying, plants are returned to a compartment at 20-25 C and moderate humidity for up to 7 days, followed by assessment.

Assessment is based on the percentage of leaf area covered by sporulation compared with that on leaves of control plants.

(e) Activity against rice leaf blast (Pyricularia oryzae Po) The test is a direct therapeutic one using a foliar spray. The leaves of rice seedlings (about 30 seedlings per pot) are sprayed with an aqueous suspension containing 105 spores/ml 20-24 hours prior to treatment with the test compound. The inoculated plants are kept overnight in high humidity and then allowed to dry before spraying with the test compound at a dosage of 1 kilogram of active material per hectare using a track sprayer as described under (a). After treatment the plants are kept in a rice compartment at 25-30OC and high humidity.

Assessments are made 4-5 days after treatment and are based on the density of necrotic lesions per leaf when compared with control plants.

(f) Activity against wheat eyespot in-vitro PseudocercosPorella herpotrichoides; PhI) This test measures the in vitro activity of compounds against the fungus causing wheat eyespot.

The test compound is dissolved or suspended in acetone and is added to molten half strength Potato Dextrose Agar to give a final concentration of 100ppm compound and 3.5% acetone. After the agar has set, plates are inoculated with 6mm diameter plugs of agar/mycelium taken from a 14 day old culture of P. herpotrichoides.

Plates are incubated at 200C for 12 days and radial growth from the inoculation plug is measured.

(g) Activity against Fusarium in-vitro (Fusarium species; FsI) This test measures the in vitro activity of compounds against a species of Fusarium that causes stem and root rots.

Compound is dissolved or suspended in acetone and added to molten half strength Potato Dextrose Agar to give a final concentration of 100ppm compound and 3.5% acetone. After the agar has set, plates are inoculated with 6mm diameter plugs of agar and mycelium taken from a 7 day old culture of Fusarium sp..

Plates are incubated at 20 0C for 5 days and radial growth from the plug is measured.

The extent of disease control in all the above tests is expressed as a rating compared with either an untreated control or a diluent-sprayed-control, according to the criteria: 0 = less than 50% disease control 1 = about 50-808 disease control 2 = greater than 80% disease control The results of these tests are set out in Table II below: TABLE II Compound Fungicidal Activity Example No. Pva Pvp Ln Eg Po PhI FsI 1 2 1 1 2 1 1 2 1 1 3 1 2 1 1 4 2 1 5 1 2 1 1 6 2 1 7 2 1 1 8 1 2 1 1 9 1 1 2 1 10 2 1 2 1 1 11 1 2 2 1 1 12 1

Claims (16)

1. CLAIMS 1. A compound of the general formula

   or an acid-addition salt or metal salt complex thereof, in which R represents an optionally substituted alkyl or phenyl group; R1 represents an optionally substituted alkyl, alkenyl, alkynyl or benzyl group; R2 represents of hydrogen or halogen atom or an alkyl, haloalkyl, alkoxy, haloalkoxy, alkylthio, hydroxyl, cyano, nitro, amino, alkylamino or dialkylamino group; and X represents an oxygen or sulphur atom.
2. 2. A compound according to claim 1 in which R represents an alkyl or phenyl group optionally substituted by one or more substituents selected from halogen atoms, nitro, cyano, hydroxyl, alkyl, haloalkyl, alkoxy, haloalkoxy, amino, alkylamino, dialkylamino, formyl, alkoxycarbonyl, carboxyl, alkanoyl, alkylthio, alkylsulphinyl, alkylsulphonyl, carbamoyl and alkylamido groups.
3. 3. A compound according to claim 1 or claim 2 in which R represents an unsubstituted C1-4alkyl group or a phenyl group substituted by 1 to 3 halogen atoms.
4. 4. A compound according to claim 3 in which the halogen atoms are chlorine atoms.
5. 5. A compound according to any preceding claim in which R1 represents a C1-6alkyl group, a C 2-6 alkenyl group, a C2~6alkynyl group or a benzyl group, each group being optionally substituted by one or more substituents selected from halogen atoms, nitro, cyano, hydroxyl, C1-4haloalkyl, C1-4alkoxy, C1-4haloalkoxy, amino, C1-4alkylamino, di-C1-4alkylamino, formyl, C14alkoxycarbonyl and carboxyl groups.
6. 6. A compound according to any preceding claim in which R represents a propyl or dichlorophenyl group; R1 represents a methyl, ethyl, propyl, butyl, pentyl, hexyl, allyl, propynyl or 2 dichlorobenzyl group; and R2 represents a hydrogen atom.
7. 7. A compound according to claim 1 as named in any one of Examples 1 to 12.
8. 8. A process for the preparation of a compound of formula I as defined in any one of claims 1 to 7 or an acid-addition salt or metal salt complex thereof which comprises reacting a compound of the general formula

   in which R and R2 are as defined in any preceding claim and L is a leaving group, with a compound of the general formula H - X - R1 (III) in which R1 and X are as defined in any preceding claim, in the presence of a base, and, if desired, reacting the compound of formula I so obtained with a suitable acid or metal salt to form an acid-addition salt or metal salt complex thereof.
9. 9. A process according to claim 8 in which L represents a chlorine or bromine atom.
10. 10. A process according to claim 8 or claim 9 substantially as hereinbefore described in Example 1.
11. 11. A compound of formula I whenever prepared by a process according to claim 8, claim 9 or claim 10.
12. 12. A fungicidal composition which comprises a carrier and, as active ingredient, a compound of formula I or an acid-addition salt or metal salt complex thereof as defined in any one of claims 1 to 7 or 11.
13. 13. A composition according to claim 12 which comprises at least two carriers, at least one of which is a surface-active agent.
14. 14. A method of combating fungus at a locus which comprises treating the locus with a compound of formula I, or an acid-addition salt or metal salt complex thereof, as defined in any one of claims 1 to 7 or 11 or with a composition as defined in claim 12 or claim 13.
15. 15. A method according to claim 14 in which the locus comprises plants subject to or subjected to fungal attack, seeds of such plants or the medium in which the plants are growing or are to be grown.
16. 16. The use as a fungicide of a compound of formula I, or an acid-addition salt or metal salt complex thereof, as defined in any one of claims 1 to 7 or 11 or a composition as defined in claim 12 or claim 13.