Classifications

• • 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
  • A01N43/64—Biocides, pest repellants or attractants, or plant growth regulators containing heterocyclic compounds having rings with three nitrogen atoms as the only ring hetero atoms
  • A01N43/647—Triazoles; Hydrogenated triazoles
  • A01N43/653—1,2,4-Triazoles; Hydrogenated 1,2,4-triazoles

Definitions

• a MOLECULAR COMPLEX OF HEXACONAZOLE AND IMIDACLOPRID AND A PROCESS FOR PRODUCTION THEREOF The present disclosure relates to a molecular complex of hexaconazole and imidacloprid and a process for production thereof.
• Hexaconazole is a white to off-white crystalline powder having a broad-spectrum fungicidal activity. It is a systemic fungicide that particularly controls ascomycetes and basidiomycetes by inhibiting ergosterol biosynthesis. Hexaconazole rapidly degrades in soil.
• Imidacloprid is a systemic insecticide which serves as an insect neurotoxin. This insecticide is effective for controlling aphids, whiteflies, thrips, scales, psyllids, plant bugs and various other harmful pest species in a variety of different crops.
• Imidacloprid is colorless crystalline solid with a weak characteristic odor and high water solubility.
• imidacloprid goes through a series of cycles of solubilization and re-crystallization leading to the generation of large and undesirable particles. These particles cause problems such as blockage of spray nozzles during application of the product.
• solubilization and recrystallisation it is difficult to maintain imidacloprid products as a homogeneous formulation that leads to issues during transfer to dilution tanks and in ensuring correct concentration of imidacloprid on dilution.
• a pesticidal formulation comprises a molecular complex of hexaconazole and imidacloprid, having a melting point of around 105°C measured as a single melting endotherm by differential scanning calorimetry.
• a process for preparing a molecular complex of hexaconazole and imidacloprid comprises mixing hexaconazole and imidacloprid in a stoichiometric ratio in a range of 1 :20 to 20: 1 , followed by grinding to obtain a dry mixture; melting the dry mixture; and cooling the melted mixture followed by grinding to obtain a molecular complex of hexaconazole and imidacloprid having a melting point of around 105°C measured as a single melting endotherm by differential scanning calorimetry.
• a process for preparing a molecular complex of hexaconazole and imidacloprid is also disclosed in accordance with another embodiment.
• the process comprises mixing hexaconazole and imidacloprid in a stoichiometric ratio in a range of 1 :20 to 20: 1, followed by grinding to obtain a dry mixture; adding a solvent to the dry mixture followed by grinding to obtain a wet mixture; and air drying the wet mixture to obtain the molecular complex having a melting point of around 105°C measured as a single melting endotherm by differential scanning calorimetry.
• Figure 1 illustrates a comparison Powder X-ray Diffraction (PXRD) profile of various samples of molecular complex of hexaconazole and imidacloprid having different molar ratios of hexaconazole and imidacloprid.
• PXRD Powder X-ray Diffraction
• Figure 2 illustrates the comparison Differential Scanning Calorimetric (DSC) profile of various samples of molecular complex of hexaconazole and imidacloprid having different molar ratios of hexaconazole and imidacloprid.
• DSC Differential Scanning Calorimetric
• Figure 3 illustrates the comparison Fourier Transformed Infrared Spectra (FT-IR) profile of various samples of molecular complex of hexaconazole and imidacloprid having different molar ratios of hexaconazole and imidacloprid.
• FT-IR Fourier Transformed Infrared Spectra
• Figure 4 illustrates the solubility profile HPLC data of samples of imidacloprid, and molecular complex of hexaconazole and imidacloprid having different molar ratios of hexaconazole and imidacloprid.
• Figure 5 illustrates the degradation profile - HPLC data of samples of imidacloprid, and molecular complex of hexaconazole and imidacloprid having different molar ratios of hexaconazole and imidacloprid.
• the disclosure relates to a pesticidal formulation.
• the pesticidal formulation comprises a molecular complex of hexaconazole and imidacloprid.
• Molecular complex herein refers to a substance in a solid form or solid formulations, which comprises at least two pure substances which interact with each other through hydrogen bonding or any other non covalent interactions to form molecular complex including co-crystals, solvates, hydrates or eutectic combinations or solid solutions, in which at least one of the pure substance is present in the solid form.
• Hexaconazole refers to all polymorphs, solvates, and hydrates of the substance having the formula (I):
• Imidacloprid refers to all polymorphs, solvates, and hydrates of the substance having the formula (II):
• the melting point of the molecular complex of hexaconazole and imidacloprid measured as a single melting endotherm by differential scanning calorimetry is around 105 °C.
• the molar ratio of imidacloprid to hexaconazole in the molecular complex of hexaconazole and imidacloprid is in a range of 1 :20 to 20: 1 and preferably in a range of 2: 1 to 8: 1.
• suitable amounts of hexaconazole and imidacloprid may be added to the pesticidal formulation.
• the present disclosure also provides a method for producing the molecular complex of hexaconazole and imidacloprid.
• the process comprises of preparing a mixture of hexaconazole and imidacloprid in required stoichiometric ratios, grinding the mixture, melting the ground mixture by heating, cooling the melted mixture and grinding it to obtain molecular complex of hexaconazole and imidacloprid.
• the ground mixture is melted by heating it at 100 to 1 10°C.
• the melting may be carried out under an inert atmosphere.
• the process comprises of admixing hexaconazole and imidacloprid to form a dry mixture, grinding said dry mixture for a predetermined period of time, adding to the ground dry mixture a solvent to obtain a wet mixture, grinding the wet mixture and air drying the same to obtain the molecular complex of hexaconazole with imidacloprid.
• the grinding of the dry mixture may be carried out for 15 to 20 minutes.
• the process comprises of admixing hexaconazole and imidacloprid to form a dry mixture, grinding said dry mixture for a predetermined period of time, adding to the ground dry mixture a solvent and grinding the same to obtain a wet mixture, heating the wet mixture, transferring the heated wet mixture to a glass vessel and air drying to obtain molecular complex of hexaconazole with imidacloprid.
• the heating may be carried out at a temperature around 100°C for 10 minutes.
• the heating may be carried out under nitrogen atmosphere.
• the grinding of the dry mixture may be carried out for 15 to 20 minutes.
• the grinding of the wet mixture may be carried out for 30 minutes.
• the grinding may be carried out in any suitable apparatus for grinding solids.
• Such apparatus includes but is not limited to mortar mills, vibrator mills or ball mills.
• the solvent is any suitable solvent including but not limited to acetonitrile, ethanol, methanol, ethyl acetate, acetone or their mixture.
• the amount of solvent added is in a range of 0.1 ml to 5 ml per 1 gram of combined weight of hexaconazole and imidacloprid.
• hexaconazole and imidacloprid are mixed in a molar ratio of 1 :20 to 20: 1 and preferably in a ratio of 2: 1 to 8: 1.
• Hexaconazole and imidacloprid are weighed in a 2: 1 to 8: 1 molar ratios for different experiments and ground using mortar pestle for 15 minutes followed melting under inert atmosphere at around 100 to 1 10°C and subsequently cooled to room temperature and ground to finer particles to obtain molecular complex of hexaconazole and imidacloprid.
• Powder X-ray Diffraction (PXRD) profiles were obtained from 5 to 10 mg of lightly ground samples obtained from Example 1 placed over Zero background silica flat sample stage.
• X-ray diffraction data was collected on a PANalytical "X"pertPRO diffractometer on a Copper source ( a - 1.5418) powered by 40kV and 30mA with a proportional counter radiation detector.
• Samples include molecular complex of hexaconazole and imidacloprid having hexaconazole and imidacloprid in molar ratios of 2: 1, 4: 1 , 6: 1 and 8: 1.
• Data collection was done with step size 0.020°, 0.50 second per step over 5-70 ° 2 ⁇ .
• Data was analyzed using Xpert Viewer software.
• PXRD profile data presented for the region where significant peaks were observed.
• DSC Differential Scanning Calorimetric
• FT-IR Fourier transformed infrared spectra
• Figure 3 illustrates the comparison IR profile of various samples of molecular complex of hexaconazole and imidacloprid having different molar ratios of hexaconazole and imidacloprid along with pure hexaconazole and imidaclopnd.
• H denotes Hexaconazole and I denotes Imidacloprid in figure 3.
• FT-IR spectra of various molecular complex obtained from examples 1 were compared with hexaconazole and imidacloprid individually and it was found that there are significant changes in IR spectral band of functional group regions to confirm the formation novel molecular complex.
• HPLC method A Waters 717plus autosampler with UV-2487 detector system was used. Experimental conditions used were Column: C-18 (30X2.1 mm); particle size: 1.5 ⁇ ; (Merck, Purospher); flow rate: 1ml per minute; mobile phase: Water: Acetonitrile (60:40), injection volume: ⁇ 0 ⁇ L ⁇ A binary gradient system was used as the elution for imidacloprid was obtained on time gradient method. A UV-Vis detector was used on dual wavelength at 270nm and 230nm. Samples were run for 10 minutes as Imidacloprid has retention time in the time window of 5,6-5.9 minutes.
• HPLC profile of solubility of Imidacloprid of individual molecular complexes is as follows-
• a pesticidal formulation comprising a molecular complex of hexaconazole and imidacloprid, having a melting point of around 105°C measured as a single melting endotherm by differential scanning calorimetry.
• a process for preparing a molecular complex of hexaconazole and imidacloprid comprising: mixing hexaconazole and imidacloprid in a stoichiometric ratio in a range of 1 :20 to 20: 1 , followed by grinding to obtain a dry mixture; melting the dry mixture; and cooling the melted mixture followed by grinding to obtain a molecular complex of hexaconazole and imidacloprid having a melting point of around 105°C measured as a single melting endotherm by differential scanning calorimetry. Further specific embodiments are disclosed below:
• a process for preparing a molecular complex of hexaconazole and imidacloprid comprising mixing hexaconazole and imidacloprid in a stoichiometric ratio in a range of 1 :20 to 20:1 , followed by grinding to obtain a dry mixture; adding a solvent to the dry mixture followed by grinding to obtain a wet mixture; and air drying the wet mixture to obtain the molecular complex having a melting point of around 105°C measured as a single melting endotherm by differential scanning calorimetry.
• the molecular complex of hexaconazole and imidacloprid as disclosed provide broad spectrum of control on both insect and fungal for a longer duration. Additionally, the molecular complexes of hexaconazole and imidacloprid have better hydrolytic stability as compared to commercially available versions of hexaconazole and imidacloprid.

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• Life Sciences & Earth Sciences (AREA)
• Agronomy & Crop Science (AREA)
• Pest Control & Pesticides (AREA)
• Plant Pathology (AREA)
• Health & Medical Sciences (AREA)
• Engineering & Computer Science (AREA)
• Dentistry (AREA)
• General Health & Medical Sciences (AREA)
• Wood Science & Technology (AREA)
• Zoology (AREA)
• Environmental Sciences (AREA)
• Nitrogen Condensed Heterocyclic Rings (AREA)
• Nitrogen And Oxygen Or Sulfur-Condensed Heterocyclic Ring Systems (AREA)
• Agricultural Chemicals And Associated Chemicals (AREA)
• Plural Heterocyclic Compounds (AREA)

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Citations (3)

• 2014
  • 2014-11-14 IN IN3575MU2013 patent/IN2013MU03575A/en unknown
  • 2014-11-14 WO PCT/IB2014/002438 patent/WO2015071739A1/en not_active Ceased

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