WO2023051311A1 - Forme cristalline du diflufénicane, son procédé de préparation et son utilisation - Google Patents

Forme cristalline du diflufénicane, son procédé de préparation et son utilisation Download PDF

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WO2023051311A1
WO2023051311A1 PCT/CN2022/119785 CN2022119785W WO2023051311A1 WO 2023051311 A1 WO2023051311 A1 WO 2023051311A1 CN 2022119785 W CN2022119785 W CN 2022119785W WO 2023051311 A1 WO2023051311 A1 WO 2023051311A1
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diflufenican
crystalline modification
crystalline
solvent system
composition
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PCT/CN2022/119785
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English (en)
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James Timothy Bristow
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Rotam Agrochem International Company Limited
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D213/00—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members
    • C07D213/02—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members
    • C07D213/04—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom
    • C07D213/60—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
    • C07D213/78—Carbon atoms having three bonds to hetero atoms, with at the most one bond to halogen, e.g. ester or nitrile radicals
    • C07D213/81—Amides; Imides
    • C07D213/82—Amides; Imides in position 3
    • A—HUMAN NECESSITIES
    • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
    • A01N43/00—Biocides, pest repellants or attractants, or plant growth regulators containing heterocyclic compounds
    • A01N43/34—Biocides, pest repellants or attractants, or plant growth regulators containing heterocyclic compounds having rings with one nitrogen atom as the only ring hetero atom
    • A01N43/40—Biocides, pest repellants or attractants, or plant growth regulators containing heterocyclic compounds having rings with one nitrogen atom as the only ring hetero atom six-membered rings

Definitions

  • the present invention relates to a crystalline form of N- (2, 4-difluorophenyl) -2- (3- (trifluoromethyl) phenoxy) -3-pyridinecarboxamide (diflufenican) , a process for preparing this crystalline form and its use in agrochemical preparations.
  • diflufenican belongs to the chemical class of anilides with a selective herbicidal activity against a wide range of unwanted plants.
  • Diflufenican can be used for both pre-emergence and post-emergence weed control. In use, diflufenican is absorbed by the shoots of germinating seedlings with limited translocation. The mode of action of diflufenican is to prevent the plant photosynthesizing, leading to a bleaching action due to the inhibition of carotenoid biosynthesis, in turn leading to death of the plant.
  • Diflufenican is used for controlling broad leaved weeds, such as chickweed, speedwell, Viola spp., cranesbill and dead nettles in a range of crop plants, including barley, durum wheat, rye, triticale and wheat.
  • Diflufenican has the molecular formula of C 19 H 11 F 5 N 2 O 2 and a chemical structure that may be represented as follows:
  • the commercially available diflufenican is in an amorphous form and is typically manufactured by the process described in EP0053011, US4918366, EP0798296, EP02021889 or CN104402814.
  • Diflufenican is available commercially in a number of formulations. However, the dispersibility of the currently available diflufenican in the formulated products is not satisfactory. Therefore, there is a need to improve the dispersibility of diflufenican. It would also be advantageous if the storage ability of diflufenican could also be improved.
  • the novel crystalline modification of diflufenican is hereinafter referred to as “the crystalline modification I of diflufenican” .
  • the crystalline modification I has the appearance of a needle-shaped crystalline solid and is easy to filter without breakage.
  • Diflufenican can be either manufactured using one of the prior art processes on a commercial scale or can be purchased in bulk quantity through various suppliers.
  • Diflufenican can be conveniently prepared using 2- (3- (trifluoromethyl) phenoxy) nicotinic acid and 2, 4-difluoroaniline as intermediates in a single step.
  • the present invention provides a crystalline modification I of diflufenican characterized by exhibiting an X-ray powder diffractogram (XRD) recorded using Cu-K ⁇ radiation at 25°C, in which at least 4 in any combination of the following reflexes as 2 ⁇ values can be observed:
  • XRD X-ray powder diffractogram
  • the crystalline modification I of diflufenican exhibits at least 5 of the reflexes indicated above, more preferably at least 6, 7, 8, 9, 10, 11, 12, 13 or 14 of the indicated reflexes.
  • the crystalline modification I of diflufenican exhibits an X-ray powder diffractogram (XRD) recorded using Cu-K ⁇ radiation at 25°C, in which at least 4, more preferably at least 6, 7, 8, 9, 10, 11, 12, 13 or 14 in any combination, of the following reflexes as 2 ⁇ values can be observed:
  • XRD X-ray powder diffractogram
  • the crystalline modification I of diflufenican exhibits at least 5, 6, 7, 8, 9 or all, in any combination, of the following reflexes as 2 ⁇ values:
  • the crystalline modification I of diflufenican exhibits an X-ray powder diffractogram (XRD) recorded using Cu-K ⁇ radiation at 25°C substantially as shown in Figure 2.
  • XRD X-ray powder diffractogram
  • the present invention provides a crystalline modification I of diflufenican characterized by IR spectroscopy, in particular exhibiting an infrared (IR) spectrum having functional group vibration peaks at wavenumber (cm -1 , ⁇ 0.2%) of one or more of 3370, 1669, 1590, 1550, 1504, 1231, 1127, 960, 919, 818, 767, 727, 696 and 600 cm -1 .
  • the crystalline modification I of diflufenican exhibits an IR spectrum substantially as shown in Figure 1.
  • the present invention provides a crystalline modification I of diflufenican, exhibiting a melting point of about 161.5°C.
  • the present invention provides a crystalline modification I of diflufenican exhibiting a differential scanning calorimetry (DSC) profile having an endothermic melting peak with an onset at 159.2°C, a peak maximum at 161.5°C, and offset at 162.7°C.
  • DSC differential scanning calorimetry
  • the crystalline modification I of diflufenican exhibits a DSC profile substantially as shown in Figure 3.
  • the present invention provides a crystalline modification I of diflufenican according to any two of more of the first to fourth aspects of the invention, preferably characterized by an IR spectrum substantially as shown in Figure 1, and/or characterized by an XRD pattern substantially as shown in Figure 2, and/or characterized by a DSC thermogram substantially as shown in Figure 3.
  • step i) of the process solid difludenican is dissolved in a suitable solvent system comprising one or more solvents to form a solution.
  • the solvent system may comprise one or a mixture of two or more solvents which provide a solution of diflufenican from which the crystalline modification I of diflufenican may be crystallized.
  • the solvent system comprises one or more esters, more preferably one or more cyclic carbonate esters, especially one or more cyclic alkylene carbonates.
  • Preferred cyclic alkylene carbonates comprise an alkylene group having from 2 to 6 carbon atoms, more preferably from 2 to 5 carbon atoms, still more preferably from 2 to 4 carbon atoms.
  • Particularly preferred cyclic alkylene carbonates are ethylene carbonate and propylene carbonate and mixtures thereof.
  • Diflufenican may be dissolved in the solvent system at ambient temperature. More preferably, diflufenican is dissolved in the solvent system by heating to a temperature above ambient temperature to a temperature at or below the reflux temperature of the solvent system. The temperature to which the solvent system is heated will depend upon the composition of the solvent system and the solvents being employed. In one preferred embodiment, the solvent system is heated to a temperature of from 60 to 100°C, more preferably from 70 to 90°C, still more preferably from 75 to 85°C, more preferably still about 80°C.
  • the solvent system is heated to a temperature of from 20 to 60°C, more preferably from 30 to 70°C, still more preferably from 35 to 65°C, more preferably still about 40°C.
  • diflufenican is dissolved in the solvent system at or close to the reflux temperature of the solvent system.
  • Diflufenican used to form the solution in step i) of the method may be any suitable form, for example amorphous diflufenican or a crystalline form other than the crystalline modification I of diflufenican.
  • the concentration of the solution formed in step i) of the process depends upon the solubility of diflufenican in the solvent system.
  • step ii) of the process diflufenican is precipitated from the solution formed in step i) .
  • Suitable techniques for precipitating diflufenican from solution are known in the art.
  • precipitation of diflufenican from solution in the solvent system is effected by the cooling the solution formed in step i) .
  • the solution may be cooled at a temperature at or close to ambient or room temperature.
  • precipitation of the crystalline modification I of diflufenican can also be effected by adding seed crystals, which can promote or accelerate crystallization of the desired product.
  • the seed crystals employed are crystals of the crystalline modification I of diflufenican.
  • the amount of seed crystals added to the diflufenican solution may be in the range of from 0.001% to 10% by weight of diflufenican in solution, preferably 0.005%to 0.5% by weight.
  • the seed crystals are added to the solution at a temperature below the boiling point of the solvent system.
  • step iii) of the process the precipitated crystalline modification I of diflufenican obtained in step ii) is separated from the solvent system.
  • the precipitated crystalline modification I of diflufenican obtained from step ii) can be isolated by separation techniques known in the art, such as filtration, centrifugation or decantation or a combination thereof.
  • the crystalline modification I of diflufenican can be isolated from the solution by removing the solvent system. Removal of the solvent system may be effected either with or without applying vacuum. Preferably, removal of the solvent system is carried out at a temperature below the reflux temperature of the solvent system. In one embodiment, isolation of the crystalline modification I of diflufenican is carried out using vacuum filtration.
  • the crystalline modification I of diflufenican isolated in step iii) is washed.
  • Any suitable solvent may be used to wash the isolated crystalline product.
  • the solvent used to wash the isolated product comprises one or more of the solvents present in the solvent system used in step i) of the process, more preferably the isolated solid is washed in the same solvent system as used in step i) of the process.
  • the isolated solid may be washed at a temperature between room temperature and 0°C, depending on the solubility of the isolated crystals in the solvent being used for washing, in order to minimize or avoid the loss of the desired crystalline product.
  • the crystalline modification I of diflufenican obtained from the method is redissolved in the solvent system and recrystallized, that is steps i) to iii) are repeated one or more times.
  • the washings and/or the solvent of crystallization produced in any of the steps of the method may be concentrated to obtain solid diflufenican, which may be recycled.
  • the present invention provides a crystalline modification I of diflufenican obtainable by a process as hereinbefore described.
  • the crystalline modification I of diflufenican is obtainable by a process substantially as described in Example 2 hereinbelow.
  • the process of the present invention is able to provide the crystalline modification I of diflufenican in a high yield and at a high level of purity.
  • the present invention provides a crystalline material comprising a crystalline modification I of diflufenican obtained by a method as hereinbefore described, having a content of a crystalline modification I of diflufenican of at least 98% by weight.
  • the crystalline modification I of diflufenican exhibits an increased stability, for example exhibiting an increased dispersibility and suspensibility in liquid formulations and compositions.
  • the present invention provides the use of a solvent system to provide a crystalline modification of diflufenican having an improved stability.
  • Suitable solvents for use in this aspect of the invention are as described above and include the cyclic alkylene carbonates discussed hereinbefore.
  • diflufenican as a herbicide is well-known in the art and diflufenican is used on a commercial scale.
  • the crystalline modification I of diflufenican is particularly suitable for formulating into a range of agrochemical products.
  • the crystalline modification I of diflufenican is active in controlling a range of unwanted plants and weeds.
  • the crystalline modification I of diflufenican is particularly useful as an active ingredient in a herbicidal composition comprising at least one agrochemically acceptable auxiliary.
  • Techniques of formulating and applying diflufenican are known in the art, for example as disclosed in the prior art documents discussed hereinbefore. Similar formulations and techniques may be employed in an analogous manner to the crystalline modification I of diflufenican of the present invention.
  • the present invention provides a composition comprising the crystalline modification I of diflufenican as hereinbefore described and at least one auxiliary.
  • the crystalline modification I of diflufenican may be present in the composition in any suitable amount.
  • the amount of the crystalline modification I of diflufenican is less than 90% by weight of the composition, preferably less than 75% by weight of the composition, more preferably less than 60% by weight of the composition, still more preferably less than 50% by weight of the composition.
  • the amount of the crystalline modification I of diflufenican is greater than 1% by weight of the composition, preferably greater than 5% by weight of the composition, more preferably greater than 10% by weight of the composition, still more preferably greater than 20% by weight of the composition, more preferably still greater than 30% by weight of the composition.
  • the amount of the crystalline modification I of diflufenican is from 5 to 90% by weight of the composition, preferably from 10 to 80% by weight of the composition, more preferably from 20 to 70% by weight of the composition, still more preferably from 30 to 60% by weight of the composition, more preferably still from 40 to 50% by weight of the composition.
  • Processes for preparing the herbicidal compositions for controlling weeds using the crystalline modification I of diflufenican are also provided herein.
  • the crystalline modification I of diflufenican may be formulated into any suitable agrochemical formulation.
  • the composition is in the form of a suspension concentrate (SC) , an oil dispersion (OD) , water-soluble granules (SG) , a dispersible concentrate (DC) , an emulsifiable concentrate (EC) , an emulsion seed dressing, a suspension seed dressing, granules (GR) , microgranules (MG) , a suspo-emulsion (SE) or water-dispersible granules (WG) .
  • SC suspension concentrate
  • OD oil dispersion
  • SG water-soluble granules
  • DC dispersible concentrate
  • EC emulsifiable concentrate
  • emulsion seed dressing emulsion seed dressing
  • GR granules
  • MG microgranules
  • SE suspo-emulsion
  • WG water-dispersible granules
  • the composition is in the form of water-dispersible granules (WG) .
  • the composition is in the form of a suspension concentrate (SC) .
  • compositions may be prepared by mixing the crystalline modification I of diflufenican with at least one herbicidally acceptable auxiliary, for example, one or more surfactants, liquid diluents, solid diluents, wetting agents, dispersants, thickening agents, anti-foaming agents, anti-freezing agents, preservatives, antioxidants, solid adherents, inert fillers and other formulation ingredients.
  • herbicidally acceptable auxiliary for example, one or more surfactants, liquid diluents, solid diluents, wetting agents, dispersants, thickening agents, anti-foaming agents, anti-freezing agents, preservatives, antioxidants, solid adherents, inert fillers and other formulation ingredients.
  • Surfactants can be an emulsifier, dispersant or wetting agent of ionic or nonionic type.
  • examples which may be used include, but are not limited to, salts of polyacrylic acids, salts of lignosulphonic acid, salts of phenylsulphonic or naphthalenesulphonic acids, polycondensates of ethylene oxide with fatty alcohols or with fatty acids or with fatty amines, substituted phenols, especially alkylphenols, sulphosuccinic ester salts, taurine derivatives, especially alkyltaurates, or phosphoric esters of polyethoxylated phenols or alcohols.
  • Liquid diluents include, but are not limited to, water, N, N-dimethylamide, dimethyl sulfoxide, N-alkylpyrrolidone, ethylene glycol, polypropylene glycol, dibasic esters, paraffines, alkylbenzenes, alkyl naphthalenes, glycerine, triacetine, oils of olive, castor, linseed, sesame, corn, peanut, cotton-seed, soybean, rape-seed and coconut, ketones such as cyclohexanone, 2-heptanone, isophorone and 4-hydroxy-4-methyl-2-pentanone, acetates such as hexyl acetate, heptyl acetate and octyl acetate, and alcohols such as methanol, cyclohexanol, decanol, benzyl and tetrahydrofurfuryl alcohol, and mixtures thereof.
  • Solid diluents can be water-soluble or water-insoluble.
  • Water-soluble solid diluents include, but are not limited to, salts such as alkali metal phosphates, for example sodium dihydrogen phosphate, alkaline earth phosphates, sulfates of sodium, potassium, magnesium and zinc, sodium and potassium chloride, sodium acetate, sodium carbonate and sodium benzoate, and sugars and sugar derivatives such as sorbitol, lactose, sucrose and mannitol.
  • Examples of water-insoluble solid diluents include, but are not limited to clays, synthetic and diatomaceous silicas, calcium and magnesium silicates, titanium dioxide, aluminum, calcium and zinc oxide, and mixtures thereof.
  • Wetting agents include, but are not limited to, alkyl sulfosuccinates, laureates, alkyl sulfates, phosphate esters, acetylenic diols, ethoxyfluornated alcohols, ethoxylated silicones, alkyl phenol ethyoxylates, benzene sulfonates, alkyl-substituted benzene sulfonates, alkyl ⁇ -olefin sulfonates, naphthalene sulfonates, alkyl-substituted naphthalene sulfonates, condensates of naphthalene sulfonates and alkyl-substituted naphthalene sulfonates with formaldehyde, and alcohol ethoxylates, and mixtures thereof. Alkyl naphthalene sulphonates, sodium salts are particularly useful for the composition
  • Dispersants include, but are not limited to, sodium, calcium and ammonium salts of ligninsulfonates (optionally polyethoxylated) ; sodium and ammonium salts of maleic anhydride copolymers; sodium salts of condensed phenolsulfonic acid; and naphthalene sulfonate-formaldehyde condensates.
  • Ligninsulfonates such as sodium ligninsulfonates are particularly useful for the composition of the invention.
  • Naphthalene sulfonate-formaldehyde condensates such as naphthalenesulfonic acid, polymers with formaldehyde, and sodium salts are particularly useful for the composition of the invention.
  • Thickening agents include, but are not limited to, guar gum, pectin, casein, carrageenan, xanthan gum, alginates, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, and carboxymethylcellulose, and mixtures thereof.
  • Synthetic thickening agents include derivatives of the former categories, and also polyvinyl alcohols, polyacrylamides, polyvinylpyrrolidones, various polyethers, their copolymers as well as polyacrylic acids and their salts, and mixtures thereof. Alkylpolyvinylpyrrolidones are particularly useful for the composition of the invention.
  • Anti-foaming agents include all substances which can normally be used for this purpose in agrochemical compositions. Suitable anti-foam agents are known in the art and are available commercially. Particularly preferred antifoam agents are mixtures of polydimethylsiloxanes and perfluroalkylphosphonic acids, such as the silicone antifoaming agents available from GE or Compton.
  • Preservatives include all substances which can normally be used for this purpose in agrochemical compositions of this type and again are well known in the art. Suitable examples that may be mentioned include (from Bayer AG) and (from Bayer AG) .
  • Antioxidants include all substances which can normally be used for this purpose in agrochemical compositions, as is known in the art. Preference is given to butylated hydroxytoluene.
  • Solid adherents include organic adhesives, including tackifiers, such as celluloses or substituted celluloses, natural and synthetic polymers in the form of powders, granules, or lattices, and inorganic adhesives such as gypsum, silica or cement.
  • tackifiers such as celluloses or substituted celluloses, natural and synthetic polymers in the form of powders, granules, or lattices
  • inorganic adhesives such as gypsum, silica or cement.
  • Inert fillers include but are not limited to, natural ground minerals, such as kaolins, aluminas, talc, chalk, quartz, attapulgite, montmorillonite, and diatomaceous earth, or synthetic ground minerals, such as highly dispersed silicic acid, aluminum oxide, silicates, and calcium phosphates and calcium hydrogen phosphates.
  • Suitable inert fillers for granules include, for example, crushed and fractionated natural minerals, such as calcite, marble, pumice, sepiolite, and dolomite, or synthetic granules of inorganic and organic ground materials, as well as granules of organic materials, such as sawdust, coconut husks, corn cobs, and tobacco stalks.
  • formulation ingredients can also be used in the present invention such as dyes, drying agents, and the like. These ingredients are known to one skilled in the art.
  • the present invention also provides a method for controlling or preventing the growth of unwanted plants, comprising applying to the plants or their locus a herbicidally effective amount of the crystalline modification I of diflufenican as hereinbefore described, or a composition as hereinbefore described.
  • the crystalline modification I of diflufenican according to the present invention may be used in combination with one or more other active compounds, such as insecticides, attractants, sterilizing agents, bactericides, acaricides, nematicides, fungicides, growth-regulating substances, herbicides, safeners and fertilizers or with agents for improving plant properties.
  • active compounds such as insecticides, attractants, sterilizing agents, bactericides, acaricides, nematicides, fungicides, growth-regulating substances, herbicides, safeners and fertilizers or with agents for improving plant properties.
  • compositions or formulations of the invention Treatment of the plants and/or their surroundings with the compositions or formulations of the invention is carried out directly by application of the compositions or formulations to the plants or plant parts or by allowing the compositions or formulations to act on their surroundings, habitat or storage space.
  • Customary treatment methods are known in the art. Examples of these customary treatment methods include dipping, spraying, vaporizing, fogging, broadcasting, painting on in the case of propagation material, and applying one or more coats particularly in the case of seed.
  • the present invention provides the use of the crystalline modification I of diflufenican as hereinbefore described in the control of unwanted plant growth.
  • Figure 1 is an infrared (IR) spectrum of a crystalline modification I of diflufenican
  • Figure 2 is an X-ray diffraction (XRD) spectrum of a crystalline modification I of diflufenican;
  • Figure 3 is a differential scanning calorimetry (DSC) thermogram of a crystalline modification I of diflufenican.
  • Figure 4 is an X-ray powder diffraction spectrum (X-RPD) of an amorphous diflufenican.
  • the IR spectra were measured with a resolution of 4 cm -1 and with the number of scans of 16 for the crystallized samples.
  • the crystalline modification I of diflufenican can be identified by its characteristic functional group vibration peaks at wavenumbers (cm -1 , ⁇ 0.2%) of one or more of 3370, 1669, 1590, 1550, 1504, 1231, 1127, 960, 919, 818, 767, 727, 696 and 600 cm -1 as shown in Figure 1.
  • Example 1 Preparation of diflufenican in accordance with the disclosure of Example 12 in EP0053011
  • reaction sequence may be illustrated as follows:
  • Diflufenican (10 g) prepared in Example 1 was placed in a 3 neck round bottom flask along with propylene carbonate (60 mL) and the resulting slurry was heated to 80°C to form a homogeneous solution.
  • the homogeneous solution was stirred at 80°C for 2 hours and the insoluble particles, if any, were removed by filtration.
  • the resulting solution was slowly cooled to room temperature. Upon cooling, fine crystals were formed and the resulting heterogeneous mixture was stirred at 20°C for 2 hours.
  • the slurry was then filtered and washed with cold propylene carbonate (6 mL) .
  • the filtered crystals were dried under vacuum at 50°C in order to remove the propylene carbonate traces from the crystalline product.
  • the crystalline product thus obtained had a purity of about 98%.
  • the crystalline product was analyzed by IR, powder X-ray analyses and DSC, and found out to be a crystalline modification I of diflufenican.
  • the IR spectrum of the crystalline diflufenican product showed the functional group characteristic vibrations at 3370, 1669, 1590, 1550, 1504, 1231, 1127, 960, 919, 818, 767, 727, 696 and 600 cm -1 as shown in Figure 1.
  • DSC Differential scanning calorimetry
  • Diflufenican (4 g) sample prepared in Example 1 was placed in a 3-neck round bottom flask along with 30 mL of ethylene carbonate and the resulting slurry was heated to 40°C to obtain a homogeneous solution. The insoluble particles, if any, were removed by filtration and the solution was slowly cooled to ambient temperature. Fine crystals were formed during the cooling and the mixture was stirred at ambient temperature for 2 hours.
  • the slurry was filtered and the recovered solid washed with 3 mL of ethylene carbonate.
  • the filtered crystals were dried under vacuum at 40°C in order to remove the ethylene carbonate traces from the crystalline product.
  • the crystalline product thus obtained had a purity of 98% and the yield was found to be about 88%.
  • the crystalline modification I of diflufenican was obtained, as determined using X-RPD, IR spectrometry and DSC analysis.
  • Samples were prepared by mixing all the components listed in Table 2 uniformly and grinding with a Dyno-Mill (manufactured by Willy A. Bachofen AG) to obtain a suspension concentrate.
  • compositions S2 and S3 contain the crystalline modification I of diflufenican and are embodiments of the present invention.
  • Composition S1 is a comparative example.
  • compositions S5 and S6 contain the crystalline modification I of diflufenican and are embodiments of the present invention.
  • Composition S4 is a comparative example.
  • compositions S1, S2 and S3 were determined following the procedures of the Collaborative International Pesticides Analytical Council, CIPAC MT 46.3.
  • compositions S1, S2 and S3 were stored at 54°C for periods of 1 month, 3 months and 6 months.
  • concentration of diflufenican was measured at the end of each storage time by HPLC.
  • the aggregation of particles in the compositions was measured by observation.
  • the original concentration of diflufenican in each formulation was 40 %.
  • the crystalline modification I of diflufenican exhibits a significantly higher storage stability than amorphous diflufenican.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Dentistry (AREA)
  • Pest Control & Pesticides (AREA)
  • Plant Pathology (AREA)
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Abstract

L'invention concerne une modification cristalline I de N-(2, 4-difluorophényl)-2-(3- (trifluorométhyl)phénoxy)-3-pyridinecarboxamide (diflufénicane), un procédé de préparation de la modification cristalline et son utilisation dans la lutte contre la croissance de plantes nuisibles.
PCT/CN2022/119785 2021-10-01 2022-09-20 Forme cristalline du diflufénicane, son procédé de préparation et son utilisation WO2023051311A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB2114110.6A GB2611348A (en) 2021-10-01 2021-10-01 A crystalline form of diflufenican, a process for its preparation and use of the same
GB2114110.6 2021-10-01

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WO2023051311A1 true WO2023051311A1 (fr) 2023-04-06

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4618366A (en) * 1980-11-21 1986-10-21 May & Baker Limited Certain N-(2,4-difluorophenyl)-2-(3-trifluoromethylphenoxy)-nicotinamides having herbicidal activity
CN1169991A (zh) * 1996-03-28 1998-01-14 隆萨股份公司 杂芳族羧酸的芳基酰胺的制备方法
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