GB2088356A - Triazole compounds - Google Patents

Abstract

Compounds of the formula: <IMAGE> wherein R<1> is benzyl ring substituted with haloalkoxy, R<2> is alkyl, and X is C=O or CHOH; or a salt or metal complex thereof, have plant growth regulating and fungicidal activities.

Description

SPECIFICATION Heterocyclic compounds This invention relates to triazole compounds, to a process for preparing them, to fungicidal and plant growth regulating compositions containing them, and to a method of combating fungal infections in, regulating the growth of, plants using them.

British Patent Application No. 34590/76 which corresponds to Dutch Patent Application No.

77019197 (the disclosure of which Applications is incorporated herein by reference), discloses inter alia compounds of general formula (I):

wherein R1 is benzyl which is optionally ring substituted and/or optionally substituted on its alkyl moiety with alkyl, R2 is C16 alkyl, and X is CHOH, and their acid addition salts and metal complexes. The compounds are stated to have plant fungicidal and plant growth regulating activities.British Patent Specification No. 1 535777 (the disclosure of which Specification is incorporated herein by reference) discloses the corresponding ketones (i.e. the compounds wherein X is C=O), and states that the ketones have plant fungicidal activity; British Patent Specification No. 1 555576 (the disclosure of which Specification is incorporated herein by reference) states that the ketones have plant growth regulating activity.

We have now found that the compound wherein R' is benzyl ring substituted with haloalkoxy have plant growth regulating and fungicidal activity. These compounds may have advantageous environmental properties.

The compounds of the present invention have the general formula (I) wherein R' is benzyl ringsubstituted with one or two C14 haloalkoxy groups and optionally substituted on its alkyl moiety with C14 alkyl, R2 is C2s alkyl and X is C=0 or CHOH; or an acid addition salt or metal complex thereof.

The compounds of the invention contain at least one chiral centre and the compounds wherein X is CHOH contain two chiral centres. This means that these compounds can exist in four opticai isomeric forms. Two of these isomer are enantiomers (i.e. mirror images) of each other, as are the other two isomers. One pair of enantiomers are diastereoisomers of the other pair of enantiomers. The racemic mixtures, the diastereoisomeric mixtures and other mixtures can be separated into the individual isomers by methods known in the art.

The alkyl groups can be straight or branched chain; examples are methyl, ethyl, propyl, (n- or isopropyl), butyl (n-, sec-, iso- or t-butyl) and pentyl (e.g. n-pentyl).

The halogen in the haloalkoxy substituent for the benzyl is preferably fluorine or chlorine but it can be bromine or iodine. The alkyl moiety is preferably methyl or ethyl but it can be propyl or butyl as indicated above. Suitable haloalkoxy groups are trifluoromethoxy, difluoromethoxy, 1,1,2,2tetrafluoroethoxy, dichloromethoxy and chlorofluoromethoxy. The alkyl substituent on the carbon atom of the benzyl is preferably methyl.

The salts can be salts with inorganic or organic acids, e.g. hydrochloric, nitric, sulphuric, acetic, ptoluenesulphonic or oxalic acid.

Suitably the metal complex is one including, as the metal, copper, zinc, manganese or iron. It preferably has the general formula:

wherein R1, R2 and X are as defined above, M is a metal, A is an anion (e.g. a chloride, bromide, iodide, nitrate, sulphate or phosphate anion), n is 2 or 4 and y is O or an integer of 1 to 12.

Examples of the compounds of the invention are shown in Table TABLE I

Compound Melting No. R' R2 X Point ( C) 1 p-CHF2CF2O-C8H4CH2- t-Bu C=O 71 5 o 2 p-CHF2CF2O-C6H4CH2- t-Bu CHOH 1 19120 3 p-CHO-C6H4CH2- t-Bu CHOH 101-102 4 p-CF3O-C6H4CH2- t-Bu C=0 86-87 5 p-CF3O-C6H4CH2- t-Bu CHOH 109-111 6 p-CH2FO-C6H4CH2- t-Bu CHOH 7 p-CHCl2O-C6H4CH2- t-Bu CHOH 8 p-CHClFO-C8H4CH2- t-Bu CHOH The compounds of the invention wherein X is CHOH, or a salt thereof, can be prepared by reducing.

preferably at dto 1 000C and for 1 to 12 hours, a ketone of the invention (i.e. a compound wherein X is C=O) or a salt thereof. Suitable reducing agents are sodium borohydride, lithium aluminium hydride or aluminium isopropoxide. If desired, catalytic hydrogenation using a suitable metal catalyst can be used.

When the ketone is a sterically hindered ketone, a Grignard reagent, for example butylmagnesium halide (e.g. bromide or iodide) can be used as the reducing agent; when a reagent such as a butyl-magnesium halide is used, a single diastereoisomeric mixture is often produced.

The reduction can be performed by dissolving the reactants in a solvent such as diethyl ether or tetrahydrofuran (for lithium aluminium hydride reduction) or hydroxylic solvents (for sodium borohydride reduction). The reaction temperature will depend on the reactants and solvent; but generally the reaction mixture is heated under reflux. After the reaction, the product can be isolated by extraction into a convenient solvent after acidification with dilute mineral acid. On removal of the solvent in vacua, the product may be crystallised from a convenient solvent.

The ketones of the invention may be made by reacting 1 ,2,4-triazole, or a salt thereof, with a ahaloketone of general formula (II):

wherein R and R2 are as defined above and Z is halogen, preferably bromine or chlorine. This process may be carried out by heating the reactants together in the absence of a solvent or diluent, but preferably a solvent is present.

Suitable solvents are non-hydroxylic solvents such as acetonitrile, dimethylformamide, dimethyl sulfoxide, sulpholane and tetrahydrofuran. Hydroxylated solvents, for example, methanol and ethanol, may be used in certain circumstances when the presence of the hydroxyl group does not interfere with the reaction. The process can be carried out in the presence of a base such as sodium hydride, sodium ethoxide, excess imidazole or triazole, or an alkali metal carbonate (e.g. potassium carbonate). The reaction temperature will depend upon the choice of reactants, solvents and base, but generally the reaction mixture is heated under reflux. The process generally consists of dissolving the reactants in a' solvent and then isolating the product by removal of the reactant solvent in vacua. Unreacted imidazole or triazole can be removed by extraction of the product with a suitable solvent which is then washed with water. A crystallisation or other purification procedure may then be carried out if desired.

The a-halo ketones may be made by known methods.

The ketones of the invention or a salt thereof may also be made by benzylating a compound of general formula (III):

wherein R2 is as defined above. Further details of this reaction can be found in British Specification No.

1 533706, the disclosure of which Specification is incorporated herein by reference.

The compounds of the invention can also be prepared by etherifying a compound of general formula (I) wherein X and R2 are as defined above and R1 is benzyl which is ring substituted with one or two hydroxy groups and optionally substituted on its allyl moiety with C14 alkyl. Preferably the etherification is performed using, as etherification agent, a haloalkyl halide (e.g. chloride or bromide) in the presence of a base (e.g. sodium or potassium hydroxide) at a temperature of -20 to +1000C. The reaction is preferably performed in an organic and/or aqueous solvent (e.g. aqueous tetrahydrofuran).

The starting materials for this etherification are disclosed in British Patent Application No.

34590/76.

The salts and metal complexes of the compounds of the invention can be prepared from the latter in known manner. For example, the complexes can be made by reacting the uncomplexed compound with a metal salt in a suitable solvent.

The compounds of the invention wherein X is CHOH are generally prepared by the above reactions in the form of racemic mixtures. The resolution of these mixtures into the constituent enantiomers can be performed by known methods. Examples of these methods are (1) forming the diastereoisomeric salts or esters of the compound of general formula (I) with an optically active acid (e.g. camphor sulphonic acid), separating the isomeric salts or esters and converting the separated isomeric salts or esters into the enantiomers of the compound of general formula (1);; (2) forming the diastereoisomeric carbamates of the compound of general formula (F) by reacting a haloformate (e.g. chloroformate) of the latter with an optically active amine (e.g. a-methylbenzylamine), separating the isomeric carbamates, and converting the separated isomeric carbamates into the enantiomers of the compound of general formula (1); (3) forming the hemiphthate of the compound of general formula (5), redacting the hemiphthate with an optically active amine le.g. a-methylbenzylamine) to give a salt of the hemiphthate, separating the isomeric salts and converting the separated salts into the enantiomers of the compound of general formula (I); or (4) resolving the mixtures using enantio-selective crystallisation techniques (Leigh, Chemistry and Industry, 1970, pages 1016-1017, and ibid, 1977, page 36). The separation of the diastereoisomeric salts, esters and carbamates can be achieved by for example crystallisation techniques or by high pressure liquid chromatography (HPLC). Alternatively, the enantiomers can be prepared directly from the ketones of the invention by stereospecific reduction, for example by biochemical reduction (using for example yeast orAspergi/lus niger) or by hydrogenation using chiral catalysts (e.g. a Wilkinson's catalyst) or by reduction with borohydride/amino acid complexes.

The compounds, salts and metal complexes are active fungicides, particularly against the diseases Piricularia oryzae on rice Puccinia recondita, Puccinia striiformis and other rusts on wheat, Puccinia hordei, Puccinia striiformis and other rusts on barley, and rusts on other hosts e.g. coffee, apples, vegetables and - ornamental plants Erysiphe graminis (powdery mildew) on barley and wheat and other powdery mildews on various hosts such as Sphaerotheca fuliginea on cucurbits (e.g. cucumber), Podosphaera leucotricha on apples and Uncinula necator on vines Helminthosporium spp, and Rhynchosporium spp. on cereals Cercospora arachidicola on peanuts and other Cercospora species on for example sugar beet, bananas and soya beans Botrytis cinerea (grey mould) on tomatoes, strawberries, vines and other hosts Venturia inaequalis (scab) on apples Some of the compounds have also shown a broad range of activities against fungi in vitro. They have activity against various post-harvest diseases on fruit (e.g. Peniclllium digatatum and italicum on oranges and Gleosporium musarum on bananas). Further some of the compounds are active as seed dressings against: Fusarium spp., Septoria spp., Tilletia spp. (i.e. bunt, a seed borne disease of wheat), Ustilago spp., Helminthosporium spp. on cereals, Rhizoctonia solani on cotton and Corticium sasakii on rice.

The compounds can move acropetally in the plant tissue. Moreover, the compounds can be volatile enough to be active in the vapour phase against fungi on the plant.

They may also be useful as industrial (as opposed to agricultural) fungicides, e.g. in the prevention of fungal attack on wood, hides, leather and especially paint films.

The compounds also have plant growth regulating activities.

The plant growth regulating effects of the compounds are manifested as for example a stunting or dwarfing effect on the vegetative growth of woody and herbaceous mono- and di-cotyledonous plants.

Such stunting or dwarfing may be useful, for example, in peanuts, cereals and soyabean where reduction in stem growth may reduce the risk of lodging and may also permit increased amounts of fertiliser to be applied. The stunting of woody species is useful in controlling the growth of undergrowth under power lines etc. Compounds which induce stunting or dwarfing may also be useful in modifying the stem growth of sugar cane thereby increasing the concentration of sugar in the cane at harvest; in sugar cane, the flowering and ripening may be controllable by applying the compounds. Stunting of peanuts can assist in harvesting. Growth retardation of grasses can help maintenance of grass swards.

Examples of suitable grasses are Stenotaphrum secundatum (St. Augustine grass), Cynosurus cristatus, Lolium multiflorum and perenne, Agrostis tenuis, Cynodon dactylon (Bermuda grass), Dactylis glomerata, Festuca spp. (e.g. Festuca rubra) and Poa spp. (e.g. Poa pratense). The compounds may stunt grasses without significant phytotoxic effects and without deleteriously affecting the appearance (particularly the colour) of the grass; this makes such compounds attractive for use on ornamental lawns and on grass verges. They may also have an effect on flowerhead emergence in for example grasses.

The compounds can also stunt weed species present in the grasses; examples of such weed species are sedges (e.g. Cyperus spp.) and dicotyledonous weeds (e.g. daisy, plantain, knotweed, speedwell, thistle, docks and ragwort). The growth of non-crop vegetation (e.g. weeds or cover vegetation) can be retarded thus assisting in the maintenance of plantation and field crops. In fruit orchards, particularly orchards subject to soil erosion, the presence of grass cover is important. However, excessive grass growth requires substantial maintenance. The compounds of the invention could be useful in this situation as they could restrict growth without killing the plants which would lead to soil erosion; at the same time the degree of competition for nutrients and water by the grass would be reduced and this could result in an increased yield of fruit.In some cases, one grass species may be stunted more than another grass species; this selectivity could be useful for example for improving the quality of a sward by preferential suppression of the growth of undesirable species.

The dwarfing may also be useful in miniaturising ornamental, household, garden and nursery plants (e.g. poinsettias, chrysanthemums, carnations, tulips and daffodils).

As indicated above, the compounds can also be used to stunt woody species. This property can be used to control hedgerows or to shape fruit trees (e.g. apples). Some coniferous trees are not significantly stunted by the compounds so the compounds could be useful in controlling undesirable vegetation in conifer nurseries.

The plant growth regulating effect may (as implied above) manifest itself in an increase in crop yield.

In the potato, vine control in the field and inhibition of sprouting in the store may be possible.

Other plant growth regulating effects caused by the compounds include alteration of leaf angle and promotion of tillering in monocotyledonous plants. The former effect may be useful for example in altering the leaf orientation of, for example, potato crops thereby letting more light into the crops and inducing an increase in phytosynthesis and tuber weight By increasing tillering in monocotyledonous crops (e.g. rice), the numer of flowering shoots per unit area may be increased thereby increasing the overall grain yield of such crops. In grass swards an increase in tillering could lead to a denser sward which may result in increased resilience in wear.

The treatment of plants with the compounds can lead to the leaves developing a darker green colour.

The compounds may inhibit, or at least delay, the flowering of sugar beet and thereby may increase sugar yield. They may also reduce the size of sugar beet without reducing significantly the sugar yield thereby enabling an increase in planting density to be made. Similarly in other root crops (e.g. turnip, swede, mangold, parsnip, beetroot, yam and cassava) it may be possible to increase the planting density.

The compounds could be useful in restricting the vegetative growth of cotton thereby leading to an increase in cotton yield.

The compounds may be useful in rendering plants resistant to stress since the compounds can delay the emergence of plants grown from seed, shorten stem height and delay flowering; these properties could be useful in preventing frost damage in countries where there is significant snow cover in the winter since then the treated plants would remain below the snow cover during the cold weather.

Further the compounds may cause drought or cold resistance in certain plants.

When applied as seed treatments at low rates the compounds can have growth stimulating effect on plants.

In carrying out the plant growth regulating method of the invention, the amount of compound to be applied to regulate the growth of plants will depend upon a number of factors, for example the particular compound selected for use, and the identity of the plant species whose growth is to be regulated. However, in general an application rate of 0.1 to 1 5, preferably 0.1 to 5, kg per hectare is used. However, on certain plants even application rates within these ranges may give undesired phytotoxic effects. Routine tests may be necessary to determine the best rate of application of a specific compound for any specific purpose for which it is suitable.

The compounds may be used as such for fungicidal or plant growth regulating purposes but are more conveniently formulated into compositions for such usage. The invention thus provides also a fungicidal or plant growth regulating composition comprising a compound which is an enantiomer of the invention or an ester, salt or complex thereof, and a carrier or diluent.

The invention also provides a method of combating fungal diseases in a plant, which method comprises applying to the plant, to seed of the plant or to the locus of the plant or seed a compound of the invention or a salt or complex thereof.

It also provides a method of regulating the growth of a plant, which method comprises applying to the plant, to seed of the plant or to the locus of the plant or seed a compound of the invention or a salt or complex thereof as hereinbefore defined.

The compounds can be applied in a number of ways, for example they can be 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, or they can be sprayed on, dusted on or applied as a cream or past formulation, or they can be applied as a vapour. Application can be to any part of the plant, bush or tree, for example to the foliage, stems, branches or roots, or to soil surrounding the roots, or to the seed before it is pianted.

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 horticujturnl 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 dusting powders or granules comprising the active ingredient and a solid diluent or carrier, for example fillers such as kaolin, bentonite, keiselguhr, dolomite, calcium carbonate, talc, powdered magnesia, Fuller's earth, gypsum, Hewitt's earth, diatomaceous earth and China clay. Such granules can be performed 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, for example, may comprise 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 or dimethylformamide).

The compositions may also be in the form of dispersible powders, granules or grains comprising a wetting agent to facilitate the dispersion in liquids of the powder or grains which may contain also filiers and suspending agents.

The aqueous dispersions or emulsions may be prepared by dissolving the active ingredient(s) in an organic solvent optionally containing wetting, dispersing or emulsifying agent(s) and then adding the mixture to water which may also be containing wetting, dispersing or emulsifying agent(s). Suitable organic solvents are ethylene dichloride, isopropyl alcohol, propylene glycol, diacetone alcohol, toluene, kerosene, methylnaphthalene, the xylenes, trichloroethylene, furfuryl alcohol, tetrahydrofurfuryl alcohol, and glycol ethers (e.g. 2-ethoxyethanol and 2-butoxyethanol).

The compositions to be used as sprays may also be in the form ot aerosols wherein the formulation is held in a container under pressure in the presence of a propellant, e.g.

fluorotrichloromethane or dichlorodifluoromethane.

The 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.

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 compounds can be used as mixtures with fertilisers (e.g. 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 to25% by weight of the compound. The invention therefore also provides a fertiliser composition comprising a compound of the invention.

The compositions may also be in the form of liquid preparations for use as dips or sprays which are generally aqueous dispersions or emulsions containing the active ingredient in the presence of one or more surfactants e.g. wetting agent(s), dispersing agent(s), emulsifying agent(s) or suspending agents(s). 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 triisopropylnaphthalene 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 nonionic 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 the vegetable gums (for example gum acacia and gum tragacanth).

The compositions for use as aqueous dispersions or emulsions are generally supplied in the form of a concentrate containing a high proportipn of the active ingredient(s), the concentrate to be diluted with water before use. These concentrates often should 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 homogenous for a sufficient time to enable them to be applied by conventional spray equipment The concentrates may conveniently contain up to 95%, suitably 1085%, for example 2560%, by weight of the active ingredient(s). These concentrates suitably contain organic acids (e.g.

alkaryl or aryl sulphonic acids such as xylenesulphonic acid or dodecylbenzenesulphonic acid) since the presence of such acids can increase the solubility of the active ingredient(s) in the polar solvents often used in the concentrates. The concentrates suitably contain also a high proportion of surfactants so that sufficiently stable emulsions in water can be obtained. After dilution to form aqueous preparations, such preparation may contain varying amounts of the active ingredient(s) depending upon the intended purpose, but an aqueous preparation containing 0.0005% or 0.01% to 10% by weight of active ingredient(s) may be used.

The compositions of this invention can comprise also other compound(s) having biological activity, e.g. compounds having similar or complementary fungicidal or plant growth regulating activity or compounds having herbicidal or insecticidal activity.

The other fungicidal compound can be for example one which is capable of combating ear diseases of cereals (e.g. 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.

These mixtures of fungicides can have a broader spectrum of activity than the compound of general formula (I) alone; further the other fungicide can have a synergistic effect on the fungicidal activity of the compound of general formula (I). Examples of the other fungicidal compound are imazalil, benomyl, carbendazim, thiophanate-methyl, captafol, captan, sulphur, triforine, dodemorph, tridemorph, pyrazophos, furalaxyl, ethirimol, dimethirimol, bupirimate, chlorothalonil, vinclozolin, procymidone, iprodione, metalaxyl, forsetyl-aluminium, carboxin, oxycarboxin, fenarimol, nuarimol, fenfuram, methfuroxan, nitrotalisopropyl, triazdimefon, thiabendazole, triadimenol, biloxazol, dithianon, binapacryl, quinomethionate, guazitine, dodine, fentin acetate, fentin hydroxide, dinocap, folpet, dichlofluanid, ditalimphos, kitazin, cycloheximide, dichlobutrazol, a dithiocarbamate, a copper compound, a mercury compound, DPX 3217, RH2161, Chevron RE20615, CGA 64250, OGA 64251 and RO 1473169.

The compounds of the invention 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 are pirimor, croneton, dimethoate, metasystox and formothion.

The other plant growth regulating compound can be one which controls weeds or seedhead formation, improves the level or longevity of the plant growth regulating activity of the compounds of general formula (I), selectively controls the growth of the less desirable plants (e.g, grasses) or causes the compound of general formula (I) to act faster or slower as a plant growth regulating agent. Some of these other agents will be herbicides. Examples of suitable agents are the gibberellins (e.g. GA3, GA4 or GA7), the auxins (e.g. indoleacetic acid, indolebutyric acid, naphthoxyacetic acid or naphthylacetic acid), the cytokinins (e.g. kinetin, diphenylurea, benzimidazole, benzyladenine or BAP), phenoxyacetic acids, (e.g. 2,4-D or MCPA), pyridyloxyphenoxypropionic acids substituted benzoic acids (e.g.TIBA), morphactins (e.g. chlorfluorecol), maleic hydrazide, glyphosate, glyphosine, long chain fatty alcohols and acids (e.g. Off Shoot 0 or Off Shoot T), dikegulac, Sustar, Embark, substituted quaternary ammonium and phosphonium compounds (e.g. CCC, mepiquat chloride or Phosfon-D), Ethrel, carbetamide, Racuza, Alar, asulam, abscissic acid, ancymidol (and its analogues e.g.sopyrinoli RH 531 hydroxybenzonitriles (e.g. bromoxynil), Avenge, Suffix, Lontrel or thiocarbamates (e.g. Eptam).

The following Examples illustrate the invention; the temperatures are given in degrees Centigrade (o) EXAMPLE 1 I -(4-Difluoromethoxyphenyl)-4,4-dimethyl-2-(1,2,4-triazol- 7 -yl)pentan-3-ol Stage 1: 1 -(4-Methoxyphenyl)-4,4-dimethyl-2-( 1,2,4-triazol-l -yl)pentan3-ol (9 g; 0.031 M) was heated at reflux in a solution of 48% hydrobromic acid (100 ml) and glacial acetic acid (100 ml) for four hours. The reaction mixture was then poured into water (500 ml) and the pH was adjusted to 10 with 2N-sodium hydroxide solution. The mixture was extracted with diethyl ether to remove any unreacted starting material. The alkaline solution was then treated with 2N-hydrochloric acid until, at pH 7-8, a solid began to precipitate. The solid was filtered, washed well with water and recrystallised from 50% aqueous ethanol to give 1 -(4-hydroxyphenyl)-4,4-dimethyl-2-( 1 ,2,4-triazol-1 -yl)pentan-3-ol (8.2 g; yield 96%), m.p. 202-2030C.

Stage 2: The product (4 g; 0.0145M) of Stage 1 in tetrahydrofuran (20 ml) was treated with sodium hydroxide (3.2 g; 0.08M) in water (20 ml). The mixture was stirred vigorously while bubbling in chlorodifluoromethane until the temperature of the reaction mixture had dropped to -100C and the gas was refluxing in a condenser cooled by solid carbon dioxide. The mixture was allowed to reflux for three hours before pouring into water (100 ml) and extracting with diethyl ether (3 x 100 ml). The combined ethereal extracts were washed with water, dried (MgSO4) and evaporated to give a bright yellow liquid (3.2 g).This liquid was subjected to column chromatography on a silica gel (Brockmann activity lil) dry column eluting with diethyl ether to give a bright yellow solid which was recrystallised from a mixture of hexane and diethyl ether by slow evaporation to give the title compound (1.4 g; yield 30%), m.p.

101102O.

EXAMPLE 2 1 -(4-Trifluoromethoxyphenyl)-4,4-dimethyl-2-( 1,2,4-triazol- 1 -yl)pentan-3-one and 1-/4- Trifluoromethoxyphenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)pentan-3-ol Stage 1: 4-Trifluoromethoxytoluene (3.4 g; 0.0193M) in dry carbon tetrachloride (50 ml) was brought to reflux and an intimate mixture of N-bromosuccinimide (3.7 g; 0.02078M) and benzoylperoxide (0.3 g; a catalyst) was added. The resultant suspension was stirred at reflux for 30 minutes before cooling and filtering. The filtrate was evaporated under reduced pressure and the residual liquid distilled in a bulb tube apparatus at 1 5 torr, 1 000C to give, as a colourless liquid, 4-trifluoromethoxy benzyl bromide (3.0 g).

Stage 2: Sodium hydride (0.7; 0.0146M; as 50% suspension in oil), was washed with dry diethyl ether and suspended in dry dimethyl formamide (50 ml). Solid 1 ,2,4-triazol-1 -yl-pinacolone (2.3 g; 0.0137M) was added with stirring and when the effervescence had ceased, the solution was cooled to 50C. 4 Trifluoromethoxybenzyl bromide (3.0 g; 0.011 8M) was then added and, after a short induction period, the temperature rose gradually to 1 70C before beginning to fall again. The solution was stirred for2 hours at 250C before pouring into water (200 ml); the mixture was extracted with diethyl ether (3 x 100 ml). The ethereal solution was washed with water (2 x 100 ml), dried (MgSO4) and evaporated under reduced pressure to give a pale yellow gum, which solidified on standing.The solid was recrystallised from hexane to give 1-(4-trifluoromethoxyphenyl)-4,4-dimethyl-2-(1,2,4-triazol-1- yl)pentan-3-one (2.8 g), m.p. 86-870C.

Stage 3: The product (2.2 g; 0.0065M) of Stage 2 in methanol (30 ml) was treated with stirring with solid sodium borohydride (0.1 g). After 15 minutes, the effervescence had ceased and the solutioh was poured into water (100 ml) and the mixture acidified to pH 4 with hydrochloric acid and extracted with diethyl ether (3 x 100 ml). The ethereal solution was washed with water (2 x 100 ml), dried (MgSO4) and evaporated under reduced pressure to give a colourless gum, which solidified on standing. The solid was recrystallised from hexane to give 1-(4-trifluoromethoxyphenyl)-4,4-dimethyl-2-(1,2,4-triazol-1- yl)pentan-3-ol (1.6 g), m.p. 109-11 10C.

EXAMPLE 3 The compounds were tested against a variety of foliar 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. A layer of fine sand was placed at the bottom of the pots containing the dicotyledonous plants to facilitate uptake of test compound by the roots. The test compounds were formulated by bead milling, if the compound is a solid, 20 mg of it with 5 ml of 0.4% aqueous Dispersol T, by mixing, if the compound is a liquid, 20 mg of it with 1 ml of acetone, orby mixing, if the compound is a salt, 20 mg of it with acetone/water (1:1), and the mixture so produced was diluted to the required concentration immediately before use. For the foliage diseases, suspensions (1 00 ppm active ingredient) were sprayed on to the soil.Exceptions to this were the tests on Botrytis cinerea, Piasmopara, viticola and Venturia inaequalis. 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 compound was applied to the soil (roots) and to the foliage (by spraying) one or two days before the plant was inoculated with the diseases. An exception was the test on Erysiphe graminis in which the plants were inoculated 24 hours before treatment. After inoculation, the plants were put into an appropriate environment to allow infection to take place 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 = 625% of disease on untreated plants 1 = 2659% of disease on untreated plants 0 = 60100% of disease on untreated plants The results are shown in Table II TABLE II

Puccinia Erysiphe Plasmopara Phytophthora Botrytis Cercospora Venturia Compound recondita graminis viticola infestans cinerea arachidicola inequalis Number (wheat) (barley) (vine) (tomato) (tomato) (peanut) (apple) 1 3 4 0 0 3 1 0 2 4 4 0 0 3 3 3 3 4 4 0 0 3 4 4 5 2 4 0 0 4 4 EXAMPLE 4 This Example illustrates the plant growth regulating properties of the compounds. The compounds were applied in the form of a 4000 ppm solution in distilled water containing 1% of a surfactant composition of 3.33% Synperonic NPE 1 800 and 1.67% of Tween 85 in cyclohexanone and the solution was then applied to the foliage of young seedlings of various plants. The experiments were replicated twice. After 12 or 13 days from treatment the plants were assessed for plant growth regulating effects and phytotoxic symptoms.

Table Ill shows the stunting effect of the compounds on the vegetative growth using the following grading: 1 = 0-30% retardation 2 = 31-75% retardation 3 = > 75% retardation If no figure is given, the compound was substantially inactive as a stunting agent. Additional plant growth regulating properties are indicated as follows: : G = darker green leaf colour A = apical effect T = tillering effect TABLE III

Compound Sugar Agrostis Cynodon Dactylis Number Soya Cotton Beet tenuis dactylon glomerata Wheat Barley Maize Tomato 1 G G 1 1 2 2 3GT 2G 3G 2G 2G 2G 3T 1GT 2GT 3 2G 3G 2G 2 2 2 3G 3T 2 2G 4 1G G 2G 3 2 2 2 1 1 3G 5 2G 1 3G 3 3 3 2T 2T 3G 3G 6 7 8

Claims (1)

1. CLAIM

   1. A compound of general formula (I)

   wherein R1 is benzyl ring-substituted with one or two C1-4 haloalkoxy groups and optionally substituted on its alkyl moiety with C1-4 alkyl, R2 is C2-5 alkyl and X is C=0 or CHOH; or an acid addition salt or metal complex thereof.