Process for the preparation of pyroxasulfone

Description

1 / 44 PROCESS FOR PREPARING PYROXASULFONE FIELD

[0001] This disclosure relates to a process for the preparation of pyroxasulfone. BACKGROUND

[0002] The basic information below refers to the present disclosure, but is not necessarily the state of the art.

[0003] Piroxasulfone (CAS No. 447399-55-5) is a selective pre-emergence herbicide for grasses and broadleaf weeds belonging to the oxazole / pyrazole class of herbicides. Piroxasulfone is chemically known as compound 3-[[5-(difluoromethoxy)-1-methyl-3(trifluoromethyl)pyrazol-4-yl]methylsulfonyl]-5,5-dimethyl-4H-isoxazole of Formula (I) and shown as: Formula 1

[0004] Piroxasulfone is used to control weeds such as foxtail, sedge, mistletoe, ragweed, amaranth, and similar weeds. Piroxasulfone inhibits the enzyme very long-chain fatty acid elongase (VLCFAE) in unwanted weeds that grow alongside crops such as corn, wheat, soybeans, and similar plants. It provides high efficacy against broadleaf weeds, even at low application rates.

[0005] Conventional methods for the preparation of pyroxasulfone have disadvantages, such as impurities and low product yield. These conventional processes, therefore, require purification. Petition 870250110032, dated 01 / 12 / 2025, page 5 / 49 An additional 2 / 44 of the crude product is used to remove impurities. Impurities in the product can affect the efficacy, safety, and stability of the final product and substantially increase the cost. Furthermore, the yield and purity of pyroxasulfone obtained by known processes are low.

[0006] Therefore, there is a need to provide a process for the preparation of Piroxasulfone that mitigates the aforementioned disadvantages or, at least, provides an alternative solution. OBJECTIVES

[0007] Some of the objectives of this disclosure, which at least one modality presented in this document satisfies, are the following:

[0008] It is an objective of this disclosure to mitigate one or more background problems or, at least, to provide a useful alternative.

[0009] Another objective of this disclosure is to provide a process for the preparation of Piroxasulfone.

[0010] Another objective of this disclosure is to provide a process for the preparation of Piroxasulfone with comparatively better purity and yield.

[0011] Another objective of this disclosure is to provide a simple and economical process for the preparation of Piroxasulfone.

[0012] Another objective of this disclosure is to provide an environmentally friendly and commercially scalable process for the preparation of Piroxasulfone.

[0013] Other objectives and advantages of this disclosure will become clearer from the description below, which is not intended to limit the scope of this disclosure. BRIEF DESCRIPTION

[0014] This disclosure relates to a process for the preparation of piroxasulfone. The process comprises reacting ethyl-4,4,4-trifluoroacetoacetate (ETFAA) with a hydrazine salt in a first medium. Petition 870250110032, dated 01 / 12 / 2025, page 6 / 49 3 / 44 fluid, using a first base at a first predetermined temperature for a first predetermined period of time, to obtain 5-hydroxy-1-methyl-3-trifluoromethyl-1H-pyrazole. The 5-hydroxy-1-methyl-3-trifluoromethyl-1H-pyrazole is difluoromethylated using a difluoromethylating agent and a second base in a second fluid medium, at a second predetermined temperature, for a second predetermined period of time, to obtain 5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole. The 5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole is chloromethylated using a chloromethylating agent in the presence of a first catalyst at a third predetermined temperature for a third predetermined period of time to obtain 4-(chloromethyl)-5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole.Separately, glyoxylic acid is reacted with hydroxylamine and a halogenating agent at a fourth predetermined temperature for a fourth predetermined time period to obtain 1,1'-dibromoformaldoxime. The 1,1'-dibromoformaldoxime, a third base, and isobutylene in a third fluid medium are reacted at a fifth predetermined temperature for a fifth predetermined time period to obtain 3-bromo-5,5-dimethyl-4,5-dihydroisoxazole. The 3-bromo-5,5-dimethyl-4,5-dihydroisoxazole thus obtained is reacted with thiourea in a fourth fluid medium in the presence of a second catalyst at a sixth predetermined temperature for a sixth predetermined time period to obtain 5,5-dimethyl-4,5-dihydroisoxazole-3-ylisothiourea hydrobromide.4-(chloromethyl)-5-(difluoromethoxy)-1-methyl-3(trifluoromethyl)-1H-pyrazole is reacted with 5,5-dimethyl-4,5-dihydroisoxazol-3-ylisothiourea hydrobromide using a fourth base and in a fifth fluid medium at a seventh predetermined temperature for a seventh predetermined time period to obtain the compound 3-(((5-(difluoromethoxy)-1-methyl-3(trifluoromethyl)-1H-pyrazol-4-yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole. 3-(((5(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazol-4-yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole is oxidized using an oxidizing agent in the presence of a third catalyst in a sixth fluid medium at an eighth temperature. Petition 870250110032, dated 01 / 12 / 2025, page 7 / 49 4 / 44 predetermined by an eighth predetermined time period to obtain piroxasulfone.

[0015] In one embodiment of the present disclosure, the hydrazine salt is at least one selected from the group consisting of methyl hydrazine sulfate and methyl hydrazine hydrochloride.

[0016] In one embodiment of the present disclosure, the first fluid medium is at least one selected from the group consisting of methanol, ethanol, propanol and n-butanol.

[0017] In one embodiment of the present disclosure, the first predetermined temperature is in the range of 30 °C to 90 °C.

[0018] In one embodiment of this disclosure, the first predetermined time period is in the range of 4 to 8 hours.

[0019] In one embodiment of the present disclosure, the first base is at least one selected from the group consisting of triethylamine and diethylamine.

[0020] In one embodiment of the present disclosure, the molar ratio of the hydrazine salt to ethyl-4,4,4-trifluoroacetoacetate (ETFAA) is in the range of 1:1 to 1.5:1.

[0021] In one embodiment of the present disclosure, the second fluid medium is at least one selected from the group consisting of acetonitrile, methanol, ethanol, isopropyl alcohol, tetrahydrofuran (THF), dioxane, monoglyceride and diglyme.

[0022] In one embodiment of this disclosure, the difluoromethylating agent is chlorodifluoromethane.

[0023] In one embodiment of the present disclosure, the second predetermined temperature is in the range of 20 °C to 45 °C.

[0024] In one embodiment of this disclosure, the second predetermined time period is in the range of 2 to 10 hours.

[0025] In one embodiment of this disclosure, the molar ratio of the difluoromethylating agent to 5-hydroxy-1-methyl-3-trifluoromethyl-1H is shown in Section 870250110032, dated 01 / 12 / 2025, page 8 / 49. 5 / 44 pyrazole is in the range of 1:1 to 2.5:1.

[0026] In one embodiment of the present disclosure, the chloromethylating agent is a mixture of a chlorinating agent and an aldehyde.

[0027] In one embodiment of the present disclosure, the chlorinating agent is HCl.

[0028] In one embodiment of the present disclosure, the aldehyde is at least one selected from the group consisting of paraformaldehyde and formalin.

[0029] In one embodiment of the present disclosure, the first catalyst is at least one selected from the group consisting of methanesulfonic acid, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, benzenesulfonic acid and p-toluenesulfonic acid.

[0030] In one embodiment of the present disclosure, the third predetermined temperature is in the range of 75 °C to 100 °C.

[0031] In one embodiment of this disclosure, the third predetermined time period is in the range of 10 to 20 hours.

[0032] In one embodiment of the present disclosure, the molar ratio of the chloromethylating agent to 5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)1H-pyrazole is in the range of 6:1 to 7:1.

[0033] In one embodiment of the present disclosure, the halogenating agent is bromine.

[0034] In one embodiment of the present disclosure, the fourth predetermined temperature is in the range of -5 °C to 5 °C.

[0035] In one embodiment of this disclosure, the fourth predetermined time period is in the range of 4 to 6 hours.

[0036] In one embodiment of the present disclosure, the fifth predetermined temperature is in the range of 20 °C to 40 °C.

[0037] In one embodiment of this disclosure, the fifth predetermined time period is in the range of 1 to 2 hours.

[0038] In one version of the present disclosure, the third Petition 870250110032, dated 01 / 12 / 2025, p. 9 / 49 6 / 44 base is at least one selected from the group consisting of sodium bicarbonate, potassium bicarbonate, potassium carbonate, and sodium carbonate.

[0039] In one embodiment of the present disclosure, the third fluid medium is at least one selected from the group consisting of water, methylene dichloride and ethylene dichloride.

[0040] In one embodiment of the present disclosure, the fourth fluid medium is at least one selected from the group consisting of methanol, ethanol, isopropyl alcohol and n-butanol.

[0041] In one embodiment of the present disclosure, the second catalyst is at least one selected from the group consisting of hydrogen bromide and hydrogen chloride.

[0042] In one embodiment of the present disclosure, the sixth predetermined temperature is in the range of 20 °C to 40 °C.

[0043] In one embodiment of this disclosure, the sixth predetermined time period is in the range of 13:00 to 17:00.

[0044] In one embodiment of the present disclosure, the fourth base is at least one selected from the group consisting of sodium hydroxide, potassium carbonate, and pyridine.

[0045] In one embodiment of the present disclosure, the fifth fluid medium is at least one selected from the group consisting of water and methanol.

[0046] In one embodiment of the present disclosure, the seventh predetermined temperature is in the range of 10 °C to 40 °C.

[0047] In one embodiment of the present disclosure, the seventh predetermined time period is in the range of 3 to 35 hours.

[0048] In one embodiment of the present disclosure, the molar ratio of 5,5-dimethyl-4,5-dihydroisoxazol-3-ylisothiourea hydrobromide to 4(chloromethyl)-5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole is in the range of 1:1 to 1.5:1. Petition 870250110032, dated 01 / 12 / 2025, p. 10 / 49 7 / 44

[0049] In one embodiment of the present disclosure, the third catalyst is at least one selected from the group consisting of phosphotungstic acid, sodium tungstate, methyl tri-n-octyl ammonium hydrogen sulfate, phenylphosphonic acid, sodium phosphotungstate, phosphomolybdic acid and silicotungstic acid.

[0050] In one embodiment of the present disclosure, the sixth fluid medium is at least one selected from the group consisting of dichloroacetic acid, monochloroacetic acid, acetic acid, pivalic acid, formic acid, aliphatic alcohol and a chloroacetic acid mother liquor.

[0051] In one embodiment of the present disclosure, the oxidizing agent is hydrogen peroxide.

[0052] In one embodiment of the present disclosure, the eighth predetermined temperature is in the range of 40 °C to 80 °C.

[0053] In one embodiment of the present disclosure, the eighth predetermined time period is in the range of 2 to 20 hours.

[0054] In one embodiment of the present disclosure, the molar ratio of the oxidizing agent to 3-(((5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)1H-pyrazol-4-yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole is in the range of 2:1 to 5:1. DETAILED DESCRIPTION

[0055] This disclosure relates to a process for the preparation of pyroxasulfone.

[0056] The embodiments of this disclosure will now be described in this document. The embodiments are provided in such a way as to fully and completely convey the scope of this disclosure to those skilled in the art. Numerous details are presented, relating to specific components and methods, to provide a complete understanding of the embodiments of this disclosure. It will be evident to those skilled in the art that the details provided in the embodiments should not be interpreted as limiting the scope of this disclosure. In some embodiments, Petition 870250110032, dated 01 / 12 / 2025, page 11 / 49 8 / 44 well-known processes, apparatus structures and techniques are not described in detail.

[0057] The terminology used in this disclosure is solely for the purpose of explaining a specific embodiment and should not be considered as limiting the scope of this disclosure. As used in this disclosure, the forms a, an, and the may also include the plural, unless the context clearly suggests otherwise. The terms comprise, including, and having are open transition phrases and therefore specify the presence of the indicated features, integers, steps, operations, elements, modules, units, and / or components, but do not prohibit the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. The specific order of the steps disclosed in the method and process of this disclosure should not be interpreted as necessarily requiring their execution as described or illustrated.It should also be understood that additional or alternative steps may be employed.

[0058] As used in this document, the term and / or includes any and all combinations of one or more of the listed associated elements.

[0059] The terms first, second, third, etc., should not be interpreted as limiting the scope of this disclosure, since the aforementioned terms may only be used to distinguish one element, component, region, layer, or section from another component, region, layer, or section. Terms such as first, second, third, etc., when used in this document, do not imply a specific sequence or order unless clearly suggested by this disclosure.

[0060] Conventional methods for the preparation of pyroxasulfone have disadvantages, such as impurities and low product yield. These conventional processes, therefore, require purification. Petition 870250110032, dated 01 / 12 / 2025, page 12 / 49 9 / 44 additional of the crude product to remove impurities. Impurities in the product can affect the efficacy, safety, and stability of the final product. Furthermore, the yield and purity of pyroxasulfone obtained by known processes are low.

[0061] This disclosure provides an improved process for the preparation of piroxasulfone.

[0062] The process of this disclosure is simple, environmentally friendly, economical and results in higher yield and greater purity of pyroxasulfone.

[0063] In one aspect of the present disclosure, a process for the preparation of piroxasulfone is provided.

[0064] In one embodiment, a process for preparing piroxasulfone comprises the following steps: a. react ethyl-4,4,4-trifluoroacetoacetate (ETFAA) with a hydrazine salt in a first fluid medium using a first base at a first predetermined temperature for a first predetermined period of time to obtain 5-hydroxy-1-methyl-3-trifluoromethyl-1H-pyrazole; b. difluoromethylate 5-hydroxy-1-methyl-3-trifluoromethyl-1H-pyrazole using a difluoromethylating agent and a second base in a second fluid medium at a second predetermined temperature for a second predetermined period of time to obtain 5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole; w. chloromethylate 5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)- 1H-pyrazole using a chloromethylating agent in the presence of a first catalyst at a third predetermined temperature for a third predetermined period of time to obtain 4-(chloromethyl)-5-(difluoromethoxy)-1-methyl-3(trifluoromethyl)-1H-pyrazole; d. react glyoxylic acid separately with hydroxylamine and a halogenating agent at a fourth predetermined temperature for a fourth predetermined period of time to obtain 1,1'-dibromoformaldoxime; e. react with 1,1'-dibromoformaldoxime, a third base and Petition 870250110032, dated 01 / 12 / 2025, page 13 / 49 10 / 44 isobutylene in a third fluid medium at a fifth predetermined temperature for a fifth predetermined period of time to obtain 3-bromo-5,5-dimethyl-4,5-dihydroisoxazole; f. react 3-bromo-5,5-dimethyl-4,5-dihydroisoxazole with thiourea in a fourth fluid medium in the presence of a second catalyst at a sixth predetermined temperature for a sixth predetermined period of time to obtain 5,5-dimethyl-4,5-dihydroisoxazole-3-iliisothiourea hydrobromide; g. react 4-(chloromethyl)-5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole with 5,5-dimethyl-4,5-dihydroisoxazole-3-ylisothiourea hydrobromide using a fourth base in a fifth fluid medium at a seventh predetermined temperature for a seventh predetermined period of time to obtain 3-(((5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazol-4-yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole; and h. oxidize 3-(((5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)- 1H-pyrazol-4-yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole using an oxidizing agent in the presence of a third catalyst in a sixth fluid medium at an eighth predetermined temperature for an eighth predetermined period of time to obtain pyroxasulfone.

[0065] The process is described in detail.

[0066] First, a predetermined amount of a fluid medium is mixed with a hydrazine salt at a temperature in the range of 20 °C to 50 °C to obtain a first mixture. A predetermined amount of ethyl-4,4,4-trifluoroacetoacetate (ETFAA) is slowly added to the first mixture over a period of time in the range of 60 to 120 minutes to obtain a second mixture. To the second mixture, a predetermined amount of a first base is added over a period of time in the range of 3 to 120 minutes at a temperature in the range of 20 °C to 50 °C to obtain a reaction mass. The reaction mass is equilibrated at a first predetermined temperature for a first predetermined period of time. Petition 870250110032, dated 01 / 12 / 2025, page 14 / 49 11 / 44 to obtain 5-hydroxy-1-methyl-3-trifluoromethyl-1H-pyrazole.

[0067] In one embodiment of the present disclosure, the first fluid medium is at least one selected from the group consisting of methanol, ethanol, propanol, and n-butanol. In an exemplary embodiment of the present disclosure, the first fluid medium is methanol.

[0068] In an exemplary embodiment of the present disclosure, the hydrazine salt is at least one selected from the group consisting of methyl hydrazine sulfate and methyl hydrazine hydrochloride. In an exemplary embodiment of the present disclosure, the hydrazine salt is methyl hydrazine sulfate.

[0069] In an exemplary embodiment of this disclosure, the first predetermined temperature is in the range of 30°C to 90°C. In an exemplary embodiment of this disclosure, the first predetermined temperature is 70°C.

[0070] In one embodiment of this disclosure, the first predetermined time period is in the range of 4 to 8 hours. In an exemplary embodiment of this disclosure, the first predetermined time period is 6 hours.

[0071] In one embodiment of the present disclosure, the first base is at least one selected from the group consisting of triethylamine and diethylamine. In an exemplary embodiment of the present disclosure, the first base is triethylamine.

[0072] In one embodiment of this disclosure, the molar ratio of the hydrazine salt to ethyl-4,4,4-trifluoroacetoacetate (ETFAA) is in the range of 1:1 to 1.5:1. In an exemplary embodiment of this disclosure, the molar ratio of the hydrazine salt to ethyl-4,4,4-trifluoroacetoacetate (ETFAA) is 1.1:1.

[0073] In one embodiment of the present disclosure, the purity of 5-hydroxy-1-methyl-3-trifluoromethyl-1H-pyrazole is >99%.

[0074] In one version of this disclosure, the Petition 870250110032, dated 01 / 12 / 2025, page 15 / 49 12 / 44 yield of 5-hydroxy-1-methyl-3-trifluoromethyl-1H-pyrazole is > 80%.

[0075] In one embodiment of the present disclosure, the selectivity of 5-hydroxy-1-methyl-3-trifluoromethyl-1H-pyrazole is > 99.8%.

[0076] A schematic representation for the preparation of 5-hydroxy-1-methyl-3-trifluoromethyl-1H-pyrazole is shown in Scheme A: ch3 Ethyl-4,4,4-trifluoroacetoacetate 5-hydroxy-1-methyl-3-trifluoromethyl 1-1 H-pyrazole Scheme A

[0077] This disclosure provides a simple and economical process for the preparation of 5-hydroxy-1-methyl-3-trifluoromethyl-1H-pyrazole with comparatively higher yield, selectivity and purity.

[0078] In one embodiment of the present disclosure, the first base and the first fluid medium used in the present disclosure can be easily recovered and recycled, and is therefore the process economically and environmentally sound.

[0079] In addition, a predetermined amount of 5-hydroxy-1-methyl-3-trifluoromethyl-1H-pyrazole is mixed with a second base, under stirring, at a temperature in the range of 20 °C to 45 °C, for a period of time in the range of 15 to 60 minutes, to obtain a first mixture. To the first mixture, a predetermined amount of a second fluid medium is added to obtain a second mixture. The second mixture is difluoromethylated using a difluoromethylating agent at a second predetermined temperature, for a second predetermined period of time, to obtain 5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole. 13 / 44 pyrazole.

[0080] In one embodiment of the present disclosure, the second base is at least one selected from the group consisting of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate. In one exemplary embodiment, the second base is sodium hydroxide. In another exemplary embodiment, the second base is potassium hydroxide. In yet another exemplary embodiment, the second base is sodium carbonate. In yet another exemplary embodiment, the second base is potassium carbonate.

[0081] In one embodiment of the present disclosure, the second fluid medium is at least one selected from the group consisting of acetonitrile, methanol, ethanol, isopropyl alcohol, tetrahydrofuran (THF), dioxane, monoglyceride, and diglylene. In an exemplary embodiment, the fluid medium is acetonitrile.

[0082] In one embodiment of this disclosure, the difluoromethylating agent is chlorodifluoromethane.

[0083] In one embodiment of this disclosure, the second predetermined temperature is in the range of 20 °C to 45 °C. In an exemplary embodiment, the second predetermined temperature is 30 °C.

[0084] In one embodiment of this disclosure, the second predetermined time period is in the range of 2 to 10 hours. In an exemplary embodiment, the second predetermined time period is 5 hours.

[0085] In one embodiment of this disclosure, the molar ratio of the difluoromethylating agent to 5-hydroxy-1-methyl-3-trifluoromethyl-1H-pyrazole is in the range of 1:1 to 2.5:1. In an exemplary embodiment of this disclosure, the molar ratio of the difluoromethylating agent to 5-hydroxy-1-methyl-3-trifluoromethyl-1H-pyrazole is 2:1.

[0086] In one embodiment of the present disclosure, the purity of 5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole is >95%. Petition 870250110032, dated 01 / 12 / 2025, page 17 / 49 14 / 44

[0087] In one embodiment of the present disclosure, the yield of 5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole is >75%.

[0088] In an exemplary embodiment, a schematic representation for the preparation of 5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)1H-pyrazole is provided below as Scheme B. 5-hydroxy-1-methyl-3trifluoromethyl-1H-pyrazole 5-(difluoromethoxy)-1-methyl-3(trifluoromethyl)-1H-pyrazole Scheme B

[0089] In addition, a predetermined amount of 5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole is reacted with a chloromethylating agent in the presence of a first catalyst at a third predetermined temperature for a third predetermined period of time to obtain 4-(chloromethyl)-5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole.

[0090] In one embodiment of the present disclosure, the chloromethylating agent is a mixture of a chlorinating agent and an aldehyde.

[0091] In one embodiment of this disclosure, the chlorinating agent is HCl.

[0092] In one embodiment of the present disclosure, the aldehyde is at least one selected from the group consisting of paraformaldehyde and formalin. In an exemplary embodiment, the aldehyde is paraformaldehyde.

[0093] In one embodiment of the present disclosure, the first catalyst is at least one selected from the group consisting of methanesulfonic acid, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, benzenesulfonic acid, and p-toluenesulfonic acid. In a Petition 870250110032, dated 01 / 12 / 2025, page 18 / 49 In one exemplary embodiment, the first catalyst is methanesulfonic acid. In another exemplary embodiment, the first catalyst is monochloroacetic acid.

[0094] In one embodiment of the present disclosure, the third predetermined temperature is in the range of 75 °C to 100 °C. In an exemplary embodiment, the third predetermined temperature is 85 °C.

[0095] In one embodiment of this disclosure, the third predetermined time period is in the range of 10 to 20 hours. In an exemplary embodiment, the third predetermined time period is 15 hours.

[0096] In one embodiment of this disclosure, the molar ratio of the chloromethylating agent to 5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole is in the range of 6:1 to 7:1. In an exemplary embodiment of this disclosure, the molar ratio of the chloromethylating agent to 5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole is 6.4:1.

[0097] In one embodiment of the present disclosure, the purity of 4-(chloromethyl)-5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole is >90%.

[0098] In one embodiment of the present disclosure, the yield of 4-(chloromethyl)-5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1Hpyrazole is >80%.

[0099] In an exemplary embodiment, a schematic representation for the preparation of 4-(chloromethyl)-5-(difluoromethoxy)-1-methyl-3(trifluoromethyl)-1H-pyrazole is provided below as Scheme C. Petition 870250110032, dated 01 / 12 / 2025, page 19 / 49 16 / 44 CH) 5-(difluoromethoxy)1-methyl-3(trifluoromethyl)-IHpyrazole f3c First catalyst OCHFj + HCI + CH2O---------” ch2ci II OCHFj+HjO CH) 4-(chloromethyl)-5(difluoromethoxy)-1methyl-3(trifluoromethyl)-1Hpyrazole Scheme C

[0100] Separately, glyoxylic acid is reacted with hydroxylamine and a halogenating agent at a fourth predetermined temperature for a fourth predetermined time period to obtain 1,1'-dibromoformaldoxime.

[0101] The process is described in detail.

[0102] A predetermined amount of glyoxylic acid solution reacts with hydroxylamine sulfate at a temperature in the range of 20°C to 40°C for a period of time in the range of 2 to 4 hours to obtain hydroxyiminoacetic acid. Hydroxyiminoacetic acid reacts with a base to obtain a hydroxyiminoacetic acid salt.

[0103] Maintaining the hydroxyiminoacetic acid salt at a predetermined fourth temperature, a predetermined amount of a halogenating agent is added slowly, and the pH is maintained in the range of 3 to 4 by adding a dilute solution of sodium bicarbonate for a predetermined fourth time period to obtain 1,1'-dibromoformaldoxime.

[0104] In one embodiment of the present disclosure, the halogenating agent is bromine.

[0105] In one embodiment of this disclosure, the fourth predetermined temperature is in the range of -5 °C to 5 °C. In an exemplary embodiment of this disclosure, the fourth predetermined temperature is 0 °C. Petition 870250110032, dated 01 / 12 / 2025, p. 20 / 49 17 / 44

[0106] In one embodiment of this disclosure, the fourth predetermined time period is in the range of 4 to 6 hours. In an exemplary embodiment of this disclosure, the fourth predetermined time period is 5 hours.

[0107] In an exemplary embodiment, a schematic representation for the preparation of 1,1'-dibromoformaldoxime is provided below as Scheme D. Hydroxy-1,1'-dibromoformaldoxime iminoacetic acid Scheme D

[0108] Furthermore, predetermined quantities of a third base and a third fluid medium are mixed to obtain a first mixture. Maintaining the temperature in the range of 0 °C to 5 °C, isobutylene gas is slowly passed through for 1 to 2 hours to obtain a second mixture. Maintaining the temperature in the range of 0 °C to 5 °C, a solution of 1,1'-dibromoformaldoxime (95% pure) prepared in methylene dichloride is slowly added to the second mixture to obtain a third mixture. To the third mixture, isobutylene gas is again purged at a temperature in the range of 0 °C to 5 °C to obtain a fourth mixture, followed by heating at a fifth predetermined temperature for a fifth predetermined period of time to obtain 3-bromo-5,5-dimethyl-4,5-dihydroisoxazole.

[0109] In one aspect of this disclosure, the fifth Petition 870250110032, dated 01 / 12 / 2025, page 21 / 49 18 / 44 The predetermined temperature is in the range of 20 °C to 40 °C. In an exemplary embodiment of this disclosure, the fifth predetermined temperature is 30 °C.

[0110] In one embodiment of this disclosure, the fifth predetermined time period is in the range of 1 to 2 hours. In an exemplary embodiment of this disclosure, the fifth predetermined time period is 1.5 hours.

[0111] In one embodiment of the present disclosure, the third base is at least one selected from the group consisting of sodium bicarbonate, potassium bicarbonate, potassium carbonate, and sodium carbonate. In an exemplary embodiment of the present disclosure, the third base is sodium bicarbonate.

[0112] In one embodiment of the present disclosure, the third fluid medium is at least one selected from the group consisting of water, methylene dichloride, and ethylene dichloride. In an exemplary embodiment of the present disclosure, the third fluid medium is water.

[0113] In an exemplary embodiment, a schematic representation for the preparation of 3-bromo-5,5-dimethyl-4,5-dihydroisoxazole is provided below as Scheme E. Isobutylene 3-bromo-5,5-dimethyl-4,5-dihydroisoxazole Scheme E

[0114] Furthermore, predetermined quantities of thiourea and a fourth fluid medium are mixed to obtain a first mixture. Maintaining the temperature in the range of 20 °C to 40 °C, 3-bromo-5,5-dimethyl-4,5-dihydroisoxazole is added to the first mixture to obtain a second mixture. Petition 870250110032, dated 01 / 12 / 2025, page 22 / 49 19 / 44 A predetermined amount of a second catalyst is added to the second mixture and heated to a sixth predetermined temperature for a sixth predetermined period of time to obtain 5,5-dimethyl-4,5-dihydroisoxazol-3-ylisothiourea hydrobromide.

[0115] In one embodiment of the present disclosure, the fourth fluid medium is at least one selected from the group consisting of methanol, ethanol, isopropyl alcohol, and n-butanol. In an exemplary embodiment of the present disclosure, the fourth fluid medium is methanol.

[0116] In one embodiment of the present disclosure, the second catalyst is at least one selected from the group consisting of hydrogen bromide and hydrogen chloride. In an exemplary embodiment of the present disclosure, the second catalyst is hydrogen bromide.

[0117] In one embodiment of this disclosure, the sixth predetermined temperature is in the range of 20 °C to 40 °C. In an exemplary embodiment of this disclosure, the sixth predetermined temperature is 30 °C.

[0118] In one embodiment of this disclosure, the sixth predetermined time period is in the range of 13:00 to 17:00. In an exemplary embodiment of this disclosure, the sixth predetermined time period is 15:00.

[0119] In an exemplary embodiment, a schematic representation for the preparation of 5,5-dimethyl-4,5-dihydroisoxazol-3-ylisothiourea hydrobromide is provided below as Scheme F. Second catalyst HN / Medium fluid room HBr. H. 3-bromo-5,5-dimethyl-thiourea 5,5-dimethyl-4,5-di4,5-dihydroisoxazole hydrobromide hydroisoxazole-3-ilyisothiourea Petition 870250110032, dated 01 / 12 / 2025, page 23 / 49 20 / 44 Scheme F

[0120] Furthermore, a predetermined amount of 4(chloromethyl)-5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole is reacted with 5,5-dimethyl-4,5-dihydroisoxazole-3-ylisothiourea hydrobromide using a fourth base in a fifth fluid medium at a seventh predetermined temperature for a seventh predetermined period of time to obtain 3(((5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazol-4-yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole.

[0121] In one embodiment of the present disclosure, the fourth base is at least one selected from the group consisting of sodium hydroxide, potassium carbonate, and pyridine. In one exemplary embodiment, the base is a mixture of sodium hydroxide and potassium carbonate with a predetermined weight ratio. In another embodiment, the base is a mixture of sodium hydroxide and pyridine with a predetermined weight ratio.

[0122] In one embodiment of the present disclosure, the fifth fluid medium is at least one selected from the group consisting of water and methanol. In one exemplary embodiment of the present disclosure, the fifth fluid medium is water. In another exemplary embodiment of the present disclosure, the fifth fluid medium is methanol.

[0123] In one embodiment of this disclosure, the seventh predetermined temperature is in the range of 10 °C to 40 °C. In an exemplary embodiment of this disclosure, the seventh predetermined temperature is 25 °C.

[0124] In one embodiment of this disclosure, the seventh predetermined time period is in the range of 3 to 35 hours. In an exemplary embodiment of this disclosure, the seventh predetermined time period is 30 hours. In another exemplary embodiment of this disclosure, the seventh predetermined time period is 7 hours. In yet another exemplary embodiment of this disclosure, the seventh Petition 870250110032, dated 01 / 12 / 2025, page 24 / 49 The 21 / 44 predetermined time period is 20 hours. In yet another example of this disclosure, the seventh predetermined time period is 4 hours.

[0125] In one embodiment of the present disclosure, the molar ratio of 5,5-dimethyl-4,5-dihydroisoxazol-3-ylisothiourea hydrobromide to 4-(chloromethyl)-5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole is in the range of 1:1 to 1.5:1. In an exemplary embodiment of the present disclosure, the molar ratio of 5,5-dimethyl-4,5-dihydroisoxazol-3-ylisothiourea hydrobromide to 4-(chloromethyl)-5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole is 1.1:1.

[0126] In one embodiment of the present disclosure, 3-(((5(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazol-4-yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole has a purity >90%.

[0127] A schematic representation for the preparation of 3-(((5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazol-4yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole compounds is provided as an exemplary embodiment in Scheme G. In an exemplary embodiment. Scheme G

[0128] In a final step, a predetermined amount of 3-(((5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazol-4-yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole is mixed with a sixth fluid medium in the presence of a third catalyst at a temperature in the range of 10 °C to 40 °C to Petition 870250110032, dated 01 / 12 / 2025, page 25 / 49 22 / 44 To obtain a reaction mixture, the reaction mixture is heated to a temperature in the range of 40 °C to 80 °C to obtain a heated reaction mixture. A predetermined amount of an oxidizing agent is slowly added to the heated reaction mixture over a period of time in the range of 30 minutes to 300 minutes to obtain a reaction mass. The reaction mass is heated to a predetermined eighth temperature for a predetermined eighth period of time to obtain a mass of pyroxasulfone product.

[0129] In one embodiment of the present disclosure, the third catalyst is at least one selected from the group consisting of phosphotungstic acid, sodium tungstate, methyl tri-n-octyl ammonium hydrogen sulfate, phenylphosphonic acid, sodium phosphotungstate, phosphomolybdic acid, and silicotungstic acid. In one exemplary embodiment of the present disclosure, the third catalyst is phosphotungstic acid. In another exemplary embodiment of the present disclosure, the third catalyst is sodium tungstate. In yet another exemplary embodiment of the present disclosure, the third catalyst is phenylphosphonic acid.

[0130] In one embodiment of the present disclosure, the sixth fluid medium is at least one selected from the group consisting of dichloroacetic acid, monochloroacetic acid, acetic acid, pivalic acid, formic acid, aliphatic alcohol, and a chloroacetic acid mother liquor. In an exemplary embodiment of the present disclosure, the sixth fluid medium is the chloroacetic acid mother liquor.

[0131] In one embodiment of the present disclosure, aliphatic alcohol is at least one selected from the group consisting of methanol, ethanol, isopropanol, butanol and pentanol.

[0132] According to the modality of this disclosure, the mother liquor / residual chloroacetic acid liquor comprises: • 35% by mass to 85% by mass of dichloroacetic acid; Petition 870250110032, dated 01 / 12 / 2025, p. 26 / 49 23 / 44 • 35% to 60% monochloroacetic acid by mass; • 1% by mass to 10% by mass of acetic acid • and 1% by mass to 10% by mass of water; where the % by mass of each component is relative to the total mass of the mother liquor / residual chloroacetic acid liquor.

[0133] The use of mother liquor / residual chloroacetic acid liquor containing mixtures of acetic acid, monochloroacetic acid and dichloroacetic acid as a fluid medium makes the process of the present disclosure a sustainable process.

[0134] Furthermore, chloroacetic acid mother liquor is an effluent generated during the production of chloroacetic acid and is therefore available at low cost on the market. Chloroacetic acid mother liquor is an environmental waste and requires high processing costs for recycling / disposal. Thus, the use of chloroacetic acid mother liquor (an environmental waste / effluent) makes the process of the present disclosure economical and environmentally sound. In addition, the effluent load is also minimized, as the residual chloroacetic acid mother liquor is used instead of discharging it into the environment.

[0135] In one embodiment of the present disclosure, the oxidizing agent is hydrogen peroxide.

[0136] In one embodiment of this disclosure, the concentration of the oxidizing agent is in the range of 20% to 50%. In an exemplary embodiment of this disclosure, the concentration of the oxidizing agent is 30%. In another exemplary embodiment of this disclosure, the concentration of the oxidizing agent is 50%.

[0137] In one embodiment of the present disclosure, the predetermined eighth temperature is in the range of 40 °C to 80 °C. In an exemplary embodiment of the present disclosure, the eighth temperature Petition 870250110032, dated 01 / 12 / 2025, p. 27 / 49 The predetermined temperature for the 24 / 44 configuration is 50°C. In another exemplary embodiment of this disclosure, the eighth predetermined temperature is 67°C.

[0138] In one embodiment of this disclosure, the eighth predetermined time period is in the range of 2 to 20 hours. In an exemplary embodiment of this disclosure, the eighth predetermined time period is 5 hours. In another exemplary embodiment of this disclosure, the eighth predetermined time period is 7.5 hours. In yet another exemplary embodiment of this disclosure, the eighth predetermined time period is 8 hours. In yet another exemplary embodiment of this disclosure, the eighth predetermined time period is 13 hours. In an exemplary embodiment of this disclosure, the eighth predetermined time period is 15 hours.

[0139] In one embodiment of the present disclosure, the molar ratio of the oxidizing agent to 3-(((5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)1H-pyrazol-4-yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole is in the range of 2:1 to 5:1. In an exemplary embodiment of the present disclosure, the molar ratio of the oxidizing agent to 3-(((5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazol-4-yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole is 2.2:1. In another exemplary embodiment of this disclosure, the molar ratio of the oxidizing agent to 3-(((5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazol-4yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole is 2.4:1. In yet another exemplary embodiment of this disclosure, the molar ratio of the oxidizing agent to 3-(((5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazol-4yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole is 2.5:1.In another exemplary embodiment of this disclosure, the molar ratio of the oxidizing agent to 3-(((5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazol-4-yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole is 3.7:1.

[0140] The piroxasulfone product mass is cooled, followed by filtration and drying to obtain piroxasulfone.

[0141] In one version of the present disclosure, the mass of Petition 870250110032, dated 01 / 12 / 2025, page 28 / 49 25 / 44 The product is cooled to a temperature in the range of 10 °C to 40 °C to obtain a chilled product mass. The chilled product mass is filtered to obtain a cake. The cake is mixed with water, followed by the addition of an aqueous solution of an inorganic salt to decompose any excess oxidizing agent present in the product mass.

[0142] The inorganic salt is selected from the group consisting of sodium thiosulfate, sodium sulfite, and sodium metabisulfite. In an exemplary embodiment of the present disclosure, the inorganic salt is sodium thiosulfate.

[0143] According to the process of the present disclosure, the piroxasulfone thus obtained has a yield in the range of 80% to 95% and a purity in the range of 99% to 99.5%.

[0144] A schematic representation for the preparation of Piroxasulfone is shown in Scheme H: 3-(((5-(difluoromethoxy)-1-methyl-3(trifluoromethyl)-1H-pyrazol-4-yl)methyl)thio)- Pyroxasulfone 5,5-dimethyl-4,5-dihydroisoxazole Scheme H

[0145] The preceding description of the modalities was provided for illustrative purposes and is not intended to limit the scope of this disclosure. The Petition 870250110032, dated 01 / 12 / 2025, page 29 / 49 26 / 44 Individual components of a specific modality are generally not limited to that specific modality, but are interchangeable. Such variations should not be considered a deviation from this disclosure, and all such modifications are considered to be within the scope of this disclosure.

[0146] This disclosure is described in more detail in light of the following experiments, which are presented for illustrative purposes only and should not be interpreted as limiting the scope of the disclosure. The following experiments are scalable to industrial / commercial processes. EXPERIMENTAL DETAILS EXPERIMENT 1: PREPARATION OF 5-HYDROXY-1-METHYL-3-TRIFLUOROMETIL-1H-PYRAZOLE ACCORDING TO THE PRESENT DISCLOSURE (STEP A)

[0147] 250 ml of methanol were loaded into a reactor, followed by the addition of 158.5 g (1.1 mol) of methylhydrazine sulfate at 30 °C to obtain a first mixture. Maintaining the temperature at 30 °C, 192.0 g (1.0 mol) of ethyl-4,4,4-trifluoroacetoacetate (ETFAA) were slowly added to the first mixture, under stirring for 90 minutes, to obtain a second mixture. To the second mixture, 113.4 g (1.1 mol) of triethylamine (TEA) were slowly added, under stirring, for 60 minutes at 30 °C, to obtain a reaction mass. The reaction mass was equilibrated at 30 °C for 30 minutes and heated to 70 °C for 6 hours to obtain a 5-hydroxy-1-methyl-3-trifluoromethyl-1H-pyrazole product mixture with a conversion of >99%.

[0148] The product mixture was cooled to 50 °C, followed by the addition of 500 ml of water to obtain a paste. The methanol in the paste was removed by vacuum distillation below 60 °C to obtain a white paste. The white paste thus obtained was cooled to 10 °C and filtered to obtain a wet cake and a filtrate. The wet cake was washed with 500 ml of water and dried at 100 °C under vacuum to obtain 5-hydroxy-1-methyl-3-trifluoromethyl-1H-pyrazole. Petition 870250110032, dated 01 / 12 / 2025, page 30 / 49 27 / 44

[0149] The yield of 5-hydroxy-1-methyl-3-trifluoromethyl-1Hpyrazole was 84.6%, the purity was 99%, and the selectivity was 99.8%. Recovery of tea from tea sulfate in filtrate:

[0150] 220 ml of 10N NaOH were added to the filtrate to adjust the pH to 12 and convert the TEA sulfate in the filtrate to obtain a free base in a mixture. The mixture containing the free base was distilled from 80 °C to 95 °C to obtain wet TEA (wet TEA contains some amount of water). The wet TEA thus obtained was purified by fractionation to obtain TEA with purity >99.0% and moisture content <0.1%. The total TEA recovery was >85%. EXPERIMENT 2A: PREPARATION OF 5-(DIFLUOROMETHOXY)-1-METHYL-3-(TRIFLUOROMETHYL)-1H-PYRAZOLE ACCORDING TO THE PRESENT DESCRIPTION (STEP B)

[0151] 166.0 g (1.0 mol) of 5-hydroxy-1-methyl-3-trifluoromethyl-1H-pyrazole were loaded into a reactor comprising 320 g (2.0 mol) of aqueous sodium hydroxide solution (25%) under stirring at 30 °C for 30 minutes to obtain a first mixture. 1200 ml of acetonitrile were mixed into the first mixture to obtain a second mixture. Maintaining the temperature at 30 °C, 173 g (2.0 mol) of chlorodifluoromethane gas were passed into the second mixture in the reactor slowly for 3 hours, followed by stirring for 5 hours to obtain a biphasic mixture comprising an organic layer and an aqueous layer.

[0152] The organic layer was separated and concentrated under reduced pressure to obtain 5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1Hpyrazole.

[0153] The yield of 5-(difluoromethoxy)-1-methyl-3(trifluoromethyl)-1H-pyrazole was 80% and the purity was 97%. EXPERIMENT 2B: PREPARATION OF 5-(DIFLUOROMETHOXY)-1-METHYL-3-(TRIFLUOROMETHYL)-1H-PYRAZOLE ACCORDING TO THE PRESENT Petition 870250110032, dated 01 / 12 / 2025, page 31 / 49 28 / 44 DISCLOSURE (STAGE B)

[0154] 166.0 g (1.0 mol) of 5-hydroxy-1-methyl-3-trifluoromethyl-1H-pyrazole were loaded into a reactor comprising 448 g (2.0 mol) of aqueous potassium hydroxide solution (25%) under stirring at 30 °C for 30 minutes to obtain a first mixture. 1200 ml of acetonitrile were mixed into the first mixture to obtain a second mixture. Maintaining the temperature at 30 °C, 173 g (2.0 mol) of chlorodifluoromethane gas were passed into the second mixture in the reactor slowly for 3 hours, followed by stirring for 5 hours to obtain a biphasic mixture comprising an organic layer and an aqueous layer.

[0155] The organic layer was separated and concentrated under reduced pressure to obtain 5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1Hpyrazole.

[0156] The yield of 5-(difluoromethoxy)-1-methyl-3(trifluoromethyl)-1H-pyrazole was 80% and the purity was 98%. EXPERIMENT 2C: PREPARATION OF 5-(DIFLUOROMETHOXY)-1-METHYL-3-(TRIFLUOROMETHYL)-1H-PYRAZOLE ACCORDING TO THE PRESENT DISCLOSURE (STEP B)

[0157] 166.0 g (1.0 mol) of 5-hydroxy-1-methyl-3-trifluoromethyl-1H-pyrazole were loaded into a reactor comprising 848 g (2.0 mol) of aqueous sodium carbonate solution (25%) under stirring at 30 °C for 30 minutes to obtain a first mixture. 1200 ml of acetonitrile were mixed into the first mixture to obtain a second mixture. Maintaining the temperature at 30 °C, 173 g (2.0 mol) of chlorodifluoromethane gas were passed into the second mixture in the reactor slowly for 3 hours, followed by stirring for 5 hours to obtain a biphasic mixture comprising an organic layer and an aqueous layer.

[0158] The organic layer was separated and concentrated under reduced pressure to obtain 5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1Hpyrazole. Petition 870250110032, dated 01 / 12 / 2025, page 32 / 49 29 / 44

[0159] The yield of 5-(difluoromethoxy)-1-methyl-3(trifluoromethyl)-IH-pyrazole was 75% and the purity was 95%. EXPERIMENT 2D: PREPARATION OF 5-(DIFLUOROMETHOXY)-1-METHYL-3-(TRIFLUOROMETHYL)-1H-PYRAZOLE ACCORDING TO THE PRESENT DISCLOSURE (STEP B)

[0160] 166.0 g (1.0 mol) of 5-hydroxy-1-methyl-3-trifluoromethyl-1Hpyrazole were loaded into a reactor comprising 1104 g (2.0 mol) of aqueous potassium carbonate solution (25%) under stirring at 30 °C for 30 minutes to obtain a first mixture. 1200 ml of acetonitrile were mixed into the first mixture to obtain a second mixture. Maintaining the temperature at 30 °C, 173 g (2.0 mol) of chlorodifluoromethane gas were passed into the second mixture in the reactor slowly for 3 hours, followed by stirring for 5 hours to obtain a biphasic mixture comprising an organic layer and an aqueous layer.

[0161] The organic layer was separated and concentrated under reduced pressure to obtain 5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1Hpyrazole.

[0162] The yield of 5-(difluoromethoxy)-1-methyl-3(trifluoromethyl)-1H-pyrazole was 75% and the purity was 95%. EXPERIMENT 3A: PREPARATION OF 4-(CHLOROMETHYL)-5-(DIFLUOROMETHOXY)-1-METHYL-3-(TRIFLUOROMETHYL)-1H-PYRAZOLE IN ACCORDANCE WITH THE PRESENT DESCRIPTION (STEP C)

[0163] 216 g (1.0 mol) of 5-difluoromethoxy-1-methyl-3(trifluoromethyl)-1H-pyrazole were loaded into a reactor, followed by the addition of 608.3 g of aqueous HCl (30%) (5.0 mol), 42 g (1.4 mol) of paraformaldehyde and 19.2 g (0.2 mol) of methanesulfonic acid to obtain a reaction mixture. The reaction mixture was heated to 85 °C and held at 85 °C for 15 hours to obtain the resulting mixture. The reaction was monitored by HPLC for the presence of the starting material (<1%).

[0164] The resulting mixture was cooled to 30 °C to obtain a Petition 870250110032, dated 01 / 12 / 2025, page 33 / 49 30 / 44 biphasic mixture composed of an organic layer and an aqueous layer. The organic layer was separated, washed with 200 ml of aqueous sodium chloride solution (10%) and dried over magnesium sulfate to obtain 4-(chloromethyl)-5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole.

[0165] The yield of 4-(chloromethyl)-5-(difluoromethoxy)-1-methyl3-(trifluoromethyl)-1H-pyrazole was 85% and the purity was 95%. EXPERIMENT 3B: PREPARATION OF 4-(CHLOROMETHYL)-5-(DIFLUOROMETHOXY)-1-METHYL-3-(TRIFLUOROMETHYL)-1H-PYRAZOLE IN ACCORDANCE WITH THE PRESENT DESCRIPTION (STEP C)

[0166] 216 g (1.0 mol) of 5-(difluoromethoxy)-1-methyl-3(trifluoromethyl)-1H-pyrazole were loaded into a reactor, followed by the addition of 608.3 g of aqueous HCl (30%) (5.0 mol), 42 g (1.4 mol) of paraformaldehyde and 50 ml of monochloroacetic acid mother liquor to obtain a reaction mixture. The reaction mixture was heated to 85 °C and held at 85 °C for 18 hours to obtain the resulting mixture. The reaction was monitored by HPLC for the presence of the starting material (<1%).

[0167] The resulting mixture was cooled to 30 °C to obtain a biphasic mixture consisting of an organic layer and an aqueous layer. The organic layer was separated, washed with 200 ml of aqueous sodium chloride solution (10%) and dried over magnesium sulfate to obtain 4-(chloromethyl)-5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole.

[0168] The yield of 4-(chloromethyl)-5-(difluoromethoxy)-1-methyl3-(trifluoromethyl)-1H-pyrazole was 82% and the purity was >92%. EXPERIMENT 4: PREPARATION OF 1,1'-DIBROMOFORMALDOXIME ACCORDING TO THE PRESENT DESCRIPTION (STEP D)

[0169] 148 g (1.0 mol) of 50.0% glyoxylic acid solution were loaded into a reactor, followed by the slow addition of 82 g of hydroxylamine sulfate (0.5 mol) in 175 g of water, dropwise, under stirring at 30 °C for 1 hour, to obtain a first mixture. The first mixture was equilibrated at Petition 870250110032, dated 01 / 12 / 2025, pp. 34 / 49 31 / 44 °C for 90 minutes to obtain hydroxyiminoacetic acid. To the hydroxyiminoacetic acid, 187.5 ml of 10 N NaOH were added at 20 °C to obtain a sodium salt of hydroxyiminoacetic acid (pH = 3.5). The sodium salt of hydroxyiminoacetic acid was cooled to 0 °C and equilibrated for 30 minutes.

[0170] Maintaining the sodium salt of hydroxyiminoacetic acid at 0°C, 320 g (2.0 mol) of bromine were added slowly, simultaneously maintaining the pH in the range of 3 to 4 by adding dilute sodium bicarbonate solution to obtain a reaction mass. The reaction mass was stirred for 5 hours at 0°C to obtain a resultant mass.

[0171] The excess bromine in the resulting mass was decomposed by the addition of sodium thiosulfate solution followed by the addition of 500 ml of methylene dichloride and 200 ml of water to obtain a biphasic mixture comprising an organic phase and an aqueous phase. The organic layer was separated and concentrated to obtain 1,1'-dibromoformaldoxime (white solid).

[0172] The yield of 1,1'-dibromoformaldoxime was 75% and the purity was 96%. EXPERIMENT 5: PREPARATION OF 3-BROMO-5,5-DIMETHYL-4,5-DIHYDROISOXAZOLE ACCORDING TO THE PRESENT DESCRIPTION (STEP E)

[0173] 400 ml of water and 100.8 g (1.2 mol) of NaHCO3 were charged into a reactor at 30 °C, followed by the addition of 1000 ml of methylene dichloride to obtain a first mixture. The first mixture was cooled to 0 °C and, maintaining the temperature in the range of 0 °C to 5 °C, 112.0 g (2.0 mol) of isobutylene gas were slowly passed through for 90 minutes to obtain a second mixture. Maintaining the temperature in the range of 0 °C to 5 °C, 213.7 g (1.0 mol) of 1,1'-dibromoformaldoxime (95% purity), prepared in 1250 ml of methylene dichloride solution, were slowly added to the second mixture to obtain a third mixture. The third mixture was equilibrated at 0 °C for 1 hour, followed by the purging of 56.0 g (1.0 mol) of gas. Petition 870250110032, dated 01 / 12 / 2025, pp. 35 / 49 32 / 44 isobutylene at 0 °C to obtain a fourth mixture. The fourth mixture was equilibrated at 0 °C for 1 hour and then the temperature was raised to 30 °C over 90 minutes to obtain a biphasic mixture composed of an organic layer and an aqueous layer. The organic layer was fully concentrated to obtain 3-bromo-5,5-dimethyl-4,5-dihydroisoxazole.

[0174] The yield of 3-bromo-5,5-dimethyl-4,5-dihydroisoxazole was 76% and the purity was 96%. EXPERIMENT 6: PREPARATION OF 5,5-DIMETHYL-4,5-DIHYDROISOXAZOLE-3-YLISOTHIOUREA HYDROBROMIDE ACCORDING TO THE PRESENT DESCRIPTION (STEP F)

[0175] 76.0 g (1.0 mol) of thiourea and 500 ml of methanol were charged into a reactor at 30 °C to obtain a first mixture. Maintaining the temperature at 30 °C, 187.4 g (1.0 mol) of 95% pure 3-bromo-5,5-dimethyl-4,5-dihydroisoxazole were added to the first mixture to obtain a second mixture. To the second mixture, 33.75 g (0.2 mol) of aqueous hydrobromide solution were added and heated at 30 °C for 15 hours to obtain 5,5-dimethyl-4,5-dihydroisoxazole-3-ylisothiourea hydrobromide.

[0176] The yield of 5,5-dimethyl-4,5-dihydroisoxazol-3-ylisothiourea hydrobromide was 92%. EXPERIMENT 7A: PREPARATION OF 3-(((5(DIFLUOROMETHOXY)-1-METHYL-3-(TRIFLUOROMETHYL)-1H-PYRAZOL-4YL)METHYL)THIO)-5,5-DIMETHYL-4,5-DIHYDROISOXAZOLE ACCORDING TO THIS DISCLOSURE (STEP G)

[0177] 12 g (0.3 mol) of NaOH flakes and 786.6 g (5.7 mol) of K2CO3 was added to 800 ml of water, followed by cooling to 20 °C to obtain an alkaline solution. Separately, 279.4 g (1.1 mol) of 5,5-dimethyl-4,5-dihydroisoxazole-3-ylisothiourea hydrobromide was dissolved in 760 ml of water to obtain a solution. The 5,5-dimethyl-4,5-dihydroisoxazole-3-ylisothiourea hydrobromide solution was added to the alkaline solution for Petition 870250110032, dated 01 / 12 / 2025, pp. 36 / 49 33 / 44 a period of 1 hr to obtain a first mixture. Then, 264.5 g (1.0 mol) of 4-(chloromethyl)-5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole were added to the first mixture over a period of 1 hr to obtain a second mixture. The temperature of the second mixture was then raised to 25 °C and maintained at 25 °C for 30 hrs to obtain a reaction mixture comprising an organic phase and an aqueous phase. The reaction was monitored by HPLC. After 30 hrs, HPLC analysis showed <5% of 4-(chloromethyl)-5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole. The organic phase was separated from the reaction mixture to obtain a separate organic phase and a separate aqueous phase. The organic phase was separately washed with a 10% aqueous sodium chloride solution, then separated and dried over magnesium sulfate to obtain a crude 3[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4yl)-methylthio)]-4,5-dihydro 5,5-dimethyl-isoxazole.

[0178] The crude product yield of 3-(((5-(difluoromethoxy)1-methyl-3-(trifluoromethyl)-1H-pyrazol-4-yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole was 80% with a purity of 96%. EXPERIMENT 7B: PREPARATION OF 3-(((5(DIFLUOROMETHOXY)-1-METHYL-3-(TRIFLUOROMETHYL)-1H-PYRAZOL-4YL)METHYL)THIO)-5,5-DIMETHYL-4,5-DIHYDROISOXAZOLE ACCORDING TO THIS DISCLOSURE (STEP G)

[0179] 12 g (0.3 mol) of NaOH flakes and 786.6 g (5.7 mol) of K2CO3 was added to 800 ml of methanol followed by cooling to 20°C to obtain an alkaline solution. Separately, 279.4 g (1.1 mol) of 5,5-dimethyl-4,5-dihydroisoxazol-3-ylisothiourea hydrobromide was dissolved in 760 ml of methanol to obtain a solution. The 5,5-dimethyl-4,5-dihydroisoxazol-3-ylisothiourea hydrobromide solution was added to the alkaline solution over a period of 1 hr to obtain a first mixture. Then, 264.5 g (1 mol) of 4-(chloromethyl)-5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole was added to the first mixture over a period of 1 hr to obtain Petition 870250110032, dated 01 / 12 / 2025, pp. 37 / 49 34 / 44 a second mixture. Then, the temperature of the second mixture was raised to 25 °C and maintained at 25 °C for 7 hrs to obtain a reaction mixture. The reaction was monitored by HPLC. After 7 hrs, HPLC analysis showed <0.5% of 4-(chloromethyl)-5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1Hpyrazole.

[0180] 1500 ml of methylene dichloride and 1500 ml of water were added to the reaction mixture to obtain a biphasic mixture comprising an organic phase and an aqueous phase. The organic phase and the aqueous phase were separated to obtain a separate organic phase and a separate aqueous phase. The separated aqueous layer was extracted with 200 ml of methylene dichloride and a layer of methylene dichloride was separated. Both separated methylene dichloride layers (organic phase) were dried over magnesium sulfate to obtain 3-(((5-(difluoromethoxy)-1-methyl-3(trifluoromethyl)-1H-pyrazol-4-yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole. Furthermore, the separated organic phase was concentrated to remove the solvent (methylene dichloride) under reduced pressure to obtain a crude 3-(((5(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazol-4-yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole.

[0181] The yield of crude 3-(((5-(difluoromethoxy)-1-methyl-3(trifluoromethyl)-1H-pyrazol-4-yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole was 89% with a purity of 99%. EXPERIMENT 7C: PREPARATION OF CRUDE 3-(((5(DIFLUORQMETQX!)-i-met!L-3-(TR!FLUOROMET!L)-ih-pirazol-42IL)METHYL)THIO)-5,5-DIMETHYL-4,5-DIHYDROISOXAZOLE ACCORDING TO This Disclosure (STEP G)

[0182] 152 g (3.8 mol) of NaOH flakes and 27.6 g (0.2 mol) of K2CO3 was added to 800 ml of water, followed by cooling to 20 °C to obtain an alkaline solution. Separately, 279.4 g (1.1 mol) of 5,5-dimethyl-4,5-dihydroisoxazol-3-ylisothiourea hydrobromide was dissolved in 760 ml of water to obtain a solution. The 5,5-dimethyl-4,5-dihydroisoxazol-3-ylisothiourea hydrobromide solution Petition 870250110032, dated 01 / 12 / 2025, pp. 38 / 49 35 / 44 dimethyl-4,5-dihydroisoxazol-3-ylisothiourea was added to the alkaline solution over a period of 1 hr to obtain a first mixture. Then, 264.5 g (1 mol) of 4-(chloromethyl)-5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole were added to the first mixture over a period of 1 hr to obtain a second mixture. The temperature of the second mixture was then raised to 25 °C and maintained at 25 °C for 20 hrs to obtain a reaction mixture comprising an organic phase and an aqueous phase. The reaction was monitored by HPLC. After 20 hrs, HPLC analysis showed <5% of 4-(chloromethyl)-5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole. The organic phase and the aqueous phase were separated from the reaction mixture to obtain a separate organic phase and a separate aqueous phase.The separated organic phase was washed with a 10% aqueous sodium chloride solution, then separated and dried over magnesium sulfate to obtain a crude 3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio)]-4,5-dihydro 5,5-dimethylisoxazole.

[0183] The yield of the crude product of 3-(((5-(difluoromethoxy)1-methyl-3-(trifluoromethyl)-1H-pyrazol-4-yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole was 73% and the purity was 93%. EXPERIMENT 7D: PREPARATION OF 3-(((5(DIFLUOROMETHOXY)-1-METHYL-3-(TRIFLUOROMETHYL)-1H-PYRAZOL-4YL)METHYL)THIO)-5,5-DIMETHYL-4,5-DIHYDROISOXAZOLE ACCORDING TO THE PRESENT DISCLOSURE (STEP G)

[0184] 152 g (3.8 mol) of NaOH flakes and 27.6 g (0.2 mol) of K2CO3 was added to 800 ml of methanol followed by cooling to 20°C to obtain an alkaline solution. Separately, 279.4 g (1.1 mol) of 5,5-dimethyl-4,5-dihydroisoxazol-3-ylisothiourea hydrobromide was dissolved in 760 ml of methanol to obtain a solution. The 5,5-dimethyl-4,5-dihydroisoxazol-3-ylisothiourea hydrobromide solution was added to the alkaline solution over a period of 1 hr to obtain a first mixture. Then, 264.5 g (1.0 mol) of 44-(chloromethyl)-5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H Petition 870250110032, dated 01 / 12 / 2025, pp. 39 / 49 36 / 44 pyrazoles were added to the first mixture over a period of 1 hr to obtain a second mixture. Then, the temperature of the second mixture was raised to 25 °C and maintained at 25 °C for 7 hrs to obtain a reaction mixture. The reaction was monitored by HPLC. After 7 hrs, HPLC analysis showed <0.5% of 4-(chloromethyl)-5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1Hpyrazole.

[0185] 1500 ml of methylene dichloride and 1500 ml of water were added to the reaction mixture to obtain a two-phase mixture comprising an organic phase and an aqueous phase. The organic phase and the aqueous phase were separated to obtain a separate organic phase and a separate aqueous phase. The organic phase was dried separately over magnesium sulfate and then separated to obtain an organic phase containing a crude 3-(((5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazol-4-yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole. The organic phase was concentrated to remove the solvent (methylene dichloride) under reduced pressure.

[0186] The yield of crude 3-(((5-(difluoromethoxy)-1-methyl-3(trifluoromethyl)-1H-pyrazol-4-yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole was 95% and the purity was 98%. EXPERIMENT 7E: PREPARATION OF 3-(((5(DIFLUOROMETHOXY)-1-METHYL-3-(TRIFLUOROMETHYL)-1H-PYRAZOL-4YL)METHYL)THIO)-5,5-DIMETHYL-4,5-DIHYDROISOXAZOLE ACCORDING TO THE PRESENT DISCLOSURE (STEP G)

[0187] 152 g (3.8 mol) of NaOH flakes and 15.8 g (0.2 mol) of pyridine were added to 800 ml of methanol, followed by cooling to 20 °C to obtain an alkaline solution. Separately, 279.4 g (1.1 mol) of 5,5-dimethyl-4,5-dihydroisoxazole-3-ylisothiourea hydrobromide were dissolved in 760 ml of methanol to obtain a solution. The 5,5-dimethyl-4,5-dihydroisoxazole-3-ylisothiourea hydrobromide solution was added to the alkaline solution over a period of 1 hr to obtain a first mixture. In addition, 264.5 g (1 Petition 870250110032, dated 01 / 12 / 2025, pages 40 / 49 37 / 44 mol) of 4-(chloromethyl)-5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole were added to the first mixture over a period of 1 hr to obtain a second mixture. Then, the temperature of the second mixture was raised to 25 °C and maintained at 25 °C for 4 hrs to obtain a reaction mixture. The reaction was monitored by HPLC. After 4 hrs, HPLC analysis showed <0.5% of 4-(chloromethyl)-5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole.

[0188] 1500 ml of methylene dichloride and 1500 ml of water were added to the reaction mixture to obtain a two-phase mixture comprising an organic phase and an aqueous phase. The organic phase and the aqueous phase were separated to obtain a separate organic phase (methylene dichloride) and a separate aqueous phase. The aqueous phase was extracted with 200 ml of methylene dichloride and the methylene dichloride layer was separated. Both methylene dichloride layers were combined and washed with 1N HCl solution, the organic phase was washed with water and dried over magnesium sulfate to obtain a moisture-free 3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylthio)]-4,5-dihydro-5,5-dimethyl-isoxazole. The organic phase was concentrated to remove methylene dichloride under reduced pressure to obtain a crude 3-(((5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazol-4-yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole.

[0189] The yield of crude 3-(((5-(difluoromethoxy)-1-methyl-3(trifluoromethyl)-1H-pyrazol-4-yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole was 89% and the purity was 99%. EXPERIMENT 8A: PREPARATION OF PYROXASULFONE FROM 3-(((5-(DIFLUOROMETHOXY)-1-METHYL-3-(TRIFLUOROMETHYL)-1-HYRAZOL-4-YL)METHYL)THIO)-5,5-DIMETHYL-4,5-DIHYDROISOXAZOLE USING PHOSPHOTUNGSTIC ACID AS CATALYST AND METHANOL AS FLUID MEDIUM (STEP H)

[0190] A reactor was charged with 2.5 liters of methanol followed by the addition of 359 g (1 mol) of 3-(((5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)1H-pyrazol-4-yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole and 10 g of acid Petition 870250110032, dated 01 / 12 / 2025, pages 41 / 49 38 / 44 phosphotungstic acid was heated to 20 °C to obtain a reaction mixture. The reaction mixture was heated to 50 °C to obtain a heated reaction mixture. A 30% aqueous solution of hydrogen peroxide (249.3 g, 2.2 mol) was added dropwise to the heated reaction mixture over 1 hour to obtain a reaction mass. The reaction mass was heated to 50 °C under stirring and continued stirring at 50 °C for 15 hours to obtain a product mass. The pH of the product mass was adjusted to 8 using 5% NaOH solution at 50 °C. After completion of the reaction, an aqueous solution of sodium thiosulfate was added to the product mass to decompose the excess hydrogen peroxide, followed by the slow addition of 400 ml of water to obtain the resulting product mass. The resulting product mass was heated to 70 °C under stirring for 30 minutes, followed by cooling to 10 °C and filtering to obtain a cake.The cake was washed with methanol and then with water to obtain a solid product. The solid product was vacuum-dried at 80 °C to obtain pyroxasulfone.

[0191] The pyroxasulfone yield was 90% and the purity was 99%. EXPERIMENT 8B: PREPARATION OF PYROXASULFONE FROM 3-[[5-(DIFLUOROMETHOXY)-1-METHYL-3(TRIFLUOROMETHYL)PYRAZOL-4-YL]METHYLSULFANYL]-5,5-DIMETHYL-4HISOXAZOLE USING SODIUM TUNGSTATE AS A CATALYST AND METHANOL AS A FLUID MEDIUM (STEP H)

[0192] A reactor was charged with 2.5 liters of methanol followed by the addition of 359 g (1 mol) of 3-(((5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)1H-pyrazol-4-yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole and 10 g of sodium tungstate at 20 °C to obtain a reaction mixture. The reaction mixture was heated to 50 °C to obtain a heated reaction mixture. A 30% aqueous solution of hydrogen peroxide (272 g, 2.4 mol) was added dropwise to the heated reaction mixture over 1 hour to obtain a reaction mass. The reaction mass was heated to 50 °C under stirring and continued to Petition 870250110032, dated 01 / 12 / 2025, pages 42 / 49 39 / 44 stirring at 50 °C for 13 hours to obtain a mass of the product. The pH of the mass of the product was adjusted to 8 using a 5% NaOH solution at 50 °C. After the reaction was complete, an aqueous solution of sodium thiosulfate was added to the mass of the product to decompose the excess hydrogen peroxide, followed by the slow addition of 400 ml of water to obtain a mass of the resulting product. The resulting mass of the product was heated to 70 °C under stirring for 30 minutes, followed by cooling to 10 °C and filtering to obtain a cake. The cake was washed with methanol and then with water to obtain a solid product. The solid product was dried under vacuum at 80 °C to obtain pyroxasulfone.

[0193] The pyroxasulfone yield was 90.5% and the purity was 99.1%. EXPERIMENT 8C: PREPARATION OF PYROXASULFONE FROM 3-[[5-(DIFLUOROMETHOXY)-1-METHYL-3(TRIFLUOROMETHYL)PYRAZOL-4-YL]METHYLSULFANYL]-5,5-DIMETHYL-4HISOXAZOLE USING SODIUM TUNGSTATE AS A CATALYST AND DICHLOROACETIC ACID AS A FLUID MEDIUM (STEP H)

[0194] A reactor was charged with 1.9 kg of dichloroacetic acid followed by the addition of 359 g (1 mol) of 3-(((5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazol-4-yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole and 14.5 g of sodium tungstate at 20°C to obtain a reaction mixture. The reaction mixture was heated to 50°C to obtain a heated reaction mixture. A 50% aqueous solution of hydrogen peroxide (251.6, 3.7 mol) was added dropwise to the heated reaction mixture over 1 hour to obtain a reaction mass. The reaction mass was heated to 50°C under stirring and stirring continued at 50°C for 5 hours to obtain a product mass. The product mass was heated to 70 °C under stirring for 30 minutes, followed by cooling to 10 °C and filtering to obtain a cake. The cake was washed with water and then with hexane to obtain a solid product. The solid product was dried under vacuum at 80 °C to obtain pyroxasulfone. Petition 870250110032, dated 01 / 12 / 2025, pages 43 / 49 40 / 44

[0195] The pyroxasulfone yield was 85% and the purity was 99.5%. EXPERIMENT 8D: PREPARATION OF PYROXASULFONE FROM 3Σ[I5-(DIFLUOROMETOXD-1·-METHYL-3=(TRIFLUOROMETIL)PYRAZOL-4-YL]METHYLSULFANYL]-5,5-DIMETHYL-4HISOXAZOLE USING SODIUM TUNGSTATE AS A CATALYST IN A MIXTURE OF ACETIC ACID AND DICHLOROACETIC ACID (IN A 95:5 RATIO) AS THE FLUID MEDIUM (STEP H)

[0196] A reactor was charged with a 95:5 ratio of 1.783 kg of acetic acid and 0.094 kg of dichloroacetic acid, followed by the addition of 359 g (1.0 mol) of 3-(((5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazol-4-yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole and 14.5 g of sodium tungstate at 20°C to obtain a reaction mixture. The reaction mixture was heated to 50°C to obtain a heated reaction mixture. A 50% aqueous solution of hydrogen peroxide (170 g, 2.5 mol) was added dropwise to the heated reaction mixture over 1 hour to obtain a reaction mass. The reaction mass was heated to 50 °C under stirring and continued stirring at 50 °C for 8 hours to obtain a mass of the product. The product mass was cooled to 10 °C and filtered to obtain a cake. The cake was mixed with water followed by the addition of an aqueous solution of sodium thiosulfate to decompose the excess hydrogen peroxide.The cake was washed with water to obtain a solid product. The solid product was dried under vacuum at 80 °C to obtain pyroxasulfone.

[0197] The pyroxasulfone yield was 86% and the purity was 99.5%. EXPERIMENT 8E: PREPARATION OF PYROXASULFONE FROM 3-[[5-(DIFLUOROMETHOXY)-1-METHYL-3(TRIFLUOROMETHYL)PYRAZOL-4-YL]METHYLSULFANYL]-5,5-DIMETHYL-4HISOXAZOLE USING SODIUM TUNGSTATE AS A CATALYST IN A CHLOROACETIC ACID MOTHER LIQUOR CONTAINING A MIXTURE Petition 870250110032, dated 01 / 12 / 2025, pp. 44 / 49 41 / 44 ACETIC ACID, MONOCHLOROACETIC ACID AND DICHLOROACETIC ACID AS FLUID MEDIUM (STEP H)

[0198] A reactor was charged with 1.0 kg of chloroacetic acid mother liquor (containing 2% acetic acid, 42.6% monochloroacetic acid, 48.74% dichloroacetic acid, and 6.7% water) followed by the addition of 359 g (1 mol) of 3-(((5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazol-4yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole and 14.5 g of sodium tungstate at 20°C to obtain a reaction mixture. The reaction mixture was heated to 50°C to obtain a heated reaction mixture. A 50% aqueous solution of hydrogen peroxide (251.6 g, 3.7 mol) was added dropwise to the heated reaction mixture over 1 hour to obtain a reaction mass. The reaction mass was heated to 50 °C under stirring and stirring continued at 50 °C for 7.5 hours to obtain a mass of the product.620 g (34.44 m) of water were added to the product mass to make 57% chloroacetic acid mother liquor, and an aqueous solution of sodium thiosulfate was added to the product mass to decompose the excess hydrogen peroxide. The resulting product mass was cooled to 10 °C and filtered to obtain a cake. The cake was washed with water to obtain a solid product. The solid product was dried under vacuum at 80 °C to obtain pyroxasulfone.

[0199] The pyroxasulfone yield was 81% and the purity was 99%. TECHNICAL ADVANCEMENT

[0200] The present disclosure described above has several technical advantages, including, but not limited to, the implementation of a process for the preparation of pyroxasulfone that • proceeds under mild reaction conditions; • It's simple, economical, and environmentally friendly; • provides piroxasulfone with comparatively better purity and yield; Petition 870250110032, dated 01 / 12 / 2025, pages 45 / 49 42 / 44 • where the step for the preparation of 5-hydroxy-1-methyl-3-trifluoromethyl-1H-pyrazole is a green process, in which both the base and the fluid medium used in the reactions can be recovered and recycled; • wherein the step for the preparation of 5-hydroxy-1-methyl-3-trifluoromethyl-1H-pyrazole provides 5-hydroxy-1-methyl-3-trifluoromethyl-1H-pyrazole with comparatively high purity, high yield and high selectivity; and • wherein the step for the preparation of 5-hydroxy-1-methyl-3-trifluoromethyl-1H-pyrazole provides the desired isomer content of >99% in the final product.

[0201] The embodiments described in this document and their various advantageous features and details are explained with reference to non-limiting embodiments in the description below. Descriptions of well-known components and processing techniques are omitted so as not to unnecessarily obscure the embodiments described in this document. The examples used in this document are intended only to facilitate understanding of the ways in which the embodiments described in this document can be practiced and to further enable those skilled in the art to practice the embodiments described in this document. Consequently, the examples should not be interpreted as limiting the scope of the embodiments described in this document.

[0202] The preceding description of the specific modalities reveals so completely the general nature of the modalities described in this document that others may, applying current knowledge, easily modify and / or adapt such specific modalities for various applications without departing from the generic concept and, therefore, such adaptations and modifications must and should be understood within the meaning and range of equivalents of the modalities described in this document. It should be understood that the phraseology or terminology employed in this Petition 870250110032, dated 01 / 12 / 2025, pages 46 / 49 43 / 44 This document is for descriptive purposes only and not for limitation. Therefore, although the modalities described in this document have been described in terms of preferred modalities, those skilled in the art will recognize that the modalities described in this document may be practiced with modifications within the spirit and scope of the modalities described in this document.

[0203] The use of the expression "at least" or "at least one" suggests the use of one or more elements, ingredients, or quantities, as used in the embodiment of the invention, to achieve one or more of the desired objectives or results. Although certain embodiments of the inventions have been described, these embodiments are presented only by way of example and are not intended to limit the scope of the inventions. Variations or modifications to the formulation of this invention, within the scope of the invention, may occur to those skilled in the art when reviewing the disclosure presented herein. Such variations or modifications are perfectly within the spirit of this invention.

[0204] Any discussion of documents, acts, materials, devices, articles or the like that has been included in this descriptive report is for the sole purpose of providing context for disclosure. It should not be construed as an admission that any or all of these matters form part of the state of the art or were common knowledge in the relevant field for disclosure, as they existed anywhere prior to the priority date of this application.

[0205] The numerical values ​​provided for various physical parameters, dimensions and quantities are only approximate values ​​and it is anticipated that values ​​greater than the numerical value assigned to the physical parameters, dimensions and quantities are within the scope of the invention, unless there is a statement to the contrary in the descriptive report.

[0206] Although considerable emphasis has been placed in this document on the specific characteristics of the preferred modality, it should be noted Petition 870250110032, dated 01 / 12 / 2025, pp. 47 / 49 44 / 44 understand that many additional features can be added and that many changes can be made to the preferred mode of disclosure without departing from the principles of disclosure. These and other changes to the preferred mode of disclosure will be evident to those skilled in the art from the disclosure presented in this document, and it should be clearly understood that the descriptive question above should be interpreted merely as illustrative of the disclosure and not as a limitation. Petition 870250110032, dated 01 / 12 / 2025, pp. 48 / 49

Claims

1 / 5 CLAIMS 1. Process for the preparation of piroxasulfone, said process characterized by comprising the following steps: a. reacting ethyl-4,4,4-trifluoroacetoacetate (ETFAA) with a hydrazine salt in a first fluid medium using a first base at a first predetermined temperature for a first predetermined period of time to obtain 5-hydroxy-1-methyl-3-trifluoromethyl-1H-pyrazole; b. difluoromethylating said 5-hydroxy-1-methyl-3-trifluoromethyl-1H-pyrazole using a difluoromethylating agent and a second base in a second fluid medium at a second predetermined temperature for a second predetermined period of time to obtain 5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole; c.a. react said 5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole using a chloromethylating agent in the presence of a first catalyst at a third predetermined temperature for a third predetermined period of time to obtain 4-(chloromethyl)-5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole; b. react glyoxylic acid separately with hydroxylamine and a halogenating agent separately at a fourth predetermined temperature for a fourth predetermined period of time to obtain 1,1'-dibromoformaldoxime; c. react said 1,1'-dibromoformaldoxime, a third base and isobutylene in a third fluid medium at a fifth predetermined temperature for a fifth predetermined period of time to obtain 3-bromo-5,5-dimethyl-4,5-dihydroisoxazole; d.react said 3-bromo-5,5-dimethyl-4,5-dihydroisoxazole with thiourea in a fourth fluid medium in the presence of a second catalyst at a sixth predetermined temperature for a sixth predetermined period of time to obtain 5,5-dimethyl-4,5-dihydroisoxazole-3-iliisothiourea hydrobromide; Petition 870250090171, dated 03 / 10 / 2025, page 55 / 60 2 / 5 g. react said 4-(chloromethyl)-5-(difluoromethoxy)-1-methyl-3(trifluoromethyl)-1H-pyrazole with said 5,5-dimethyl-4,5-dihydroisoxazole-3-ylisothiourea hydrobromide using a fourth base in a fifth fluid medium at a seventh predetermined temperature for a seventh predetermined period of time to obtain 3-(((5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole-4-yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole; and h.to oxidize said 3-(((5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)1H-pyrazol-4-yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole using an oxidizing agent in the presence of a third catalyst in a sixth fluid medium at an eighth predetermined temperature for an eighth predetermined period of time to obtain pyroxasulfone.

2. Process according to claim 1, characterized in that said hydrazine salt is at least one selected from the group consisting of methyl hydrazine sulfate and methyl hydrazine hydrochloride.

3. Process according to claim 1, characterized in that i. said first fluid medium is at least one selected from the group consisting of methanol, ethanol, propanol and n-butanol; ii. said first base is at least one selected from the group consisting of triethylamine and diethylamine; iii. said first predetermined time period is in the range of 4 to 8 hours; iv. said first predetermined temperature is in the range of 30 °C to 90 °C; and v. the molar ratio of said hydrazine salt to said ethyl 4,4,4-trifluoroacetoacetate (ETFAA) is in the range of 1:1 to 1.5:

1.

4. Process according to claim 1, characterized in that said difluoromethylating agent is chlorodifluoromethane.

5. Process according to claim 1, characterized in that i. said second fluid medium is at least one selected from the group consisting of acetonitrile, methanol, ethanol, isopropyl alcohol, tetrahydrofuran (THF), dioxane, monoglyceride, and diglylene; ii. said second base is at least one selected from the group consisting of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate; iii. said second predetermined temperature is in the range of 20 °C to 45 °C; iv. said second predetermined time period is in the range of 2 hours to 10 hours; and v. the molar ratio of said difluoromethylating agent to said 5-hydroxy-1-methyl-3-trifluoromethyl-1H-pyrazole is in the range of 1:1 to 2.5:

1.

6. Process according to claim 1, characterized in that said chloromethylating agent is a mixture of a chlorinating agent and an aldehyde.

7. Process according to claim 6, characterized in that said chlorinating agent is HCl.

8. Process according to claim 6, characterized in that said aldehyde is at least one selected from the group consisting of paraformaldehyde and formalin.

9. Process according to claim 1, characterized in that i. said first catalyst is at least one selected from the group consisting of methanesulfonic acid, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, benzenesulfonic acid and p-toluenesulfonic acid; ii. said third predetermined temperature is in the range of 75 °C to 100 °C; iii. said third predetermined time period is in the range of 10 to 20 hours; and iv. the molar ratio of said chloromethylating agent to 5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole is in the range of 6:1 to 7:

1. Petition 870250090171, dated 03 / 10 / 2025, p. 57 / 60 4 / 5 10. Process according to claim 1, characterized in that said halogenating agent is bromine.

11. Process, according to claim 1, characterized i. by said fourth predetermined temperature being in the range of -5 °C to 5 °C; and ii. said fourth predetermined time period being in the range of 4 to 6 hours.

12. Process according to claim 1, characterized in that i. said fifth predetermined temperature is in the range of 20 °C to 40 °C; ii. said fifth predetermined time period is in the range of 1 hour to 2 hours; iii. said third base is at least one selected from the group consisting of sodium bicarbonate, potassium bicarbonate, potassium carbonate and sodium carbonate; and iv. said third fluid medium is at least one selected from the group consisting of water, methylene dichloride and ethylene dichloride.

13. Process according to claim 1, characterized in that said second catalyst is at least one selected from the group consisting of hydrogen bromide and hydrogen chloride.

14. Process according to claim 1, characterized in that i. said fourth fluid medium is at least one selected from the group consisting of methanol, ethanol, isopropyl alcohol and n-butanol; ii. said sixth predetermined temperature is in the range of 20°C to 40°C; and iii. said sixth predetermined time period is in the range of 13 to 17 hours.

15. Process, according to claim 1, characterized in that i. said fourth base is at least one selected from the group consisting of sodium hydroxide, potassium carbonate and pyridine; ii. said fifth fluid medium is at least one selected from the group consisting of water and methanol; iii. said seventh predetermined temperature is in the range of 10 °C to 40 °C; iv. said seventh predetermined time period is in the range of 3 to 35 hours; and v. the molar ratio of said 5,5-dimethyl-4,5-dihydroisoxazol-3-ylisothiourea hydrobromide to said 4-(chloromethyl)-5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazole being in the range of 1:1 to 1.5:

1.

16. Process according to claim 1, characterized in that said sixth fluid medium is at least one selected from the group consisting of dichloroacetic acid, monochloroacetic acid, acetic acid, pivalic acid, formic acid, aliphatic alcohol and a chloroacetic acid mother liquor.

17. Process according to claim 1, characterized in that said third catalyst is at least one selected from the group consisting of phosphotungstic acid, sodium tungstate, methyl tri-n-octyl ammonium hydrogen sulfate, phenylphosphonic acid, sodium phosphotungstate, phosphomolybdic acid and silicotungstic acid.

18. Process according to claim 1, characterized in that the oxidizing agent is hydrogen peroxide.

19. Process according to claim 1, characterized in that i. said predetermined eighth temperature is in the range of 40 °C to 80 °C; ii. said predetermined eighth time period is in the range of 2 hours to 20 hours; and iii. the molar ratio of said oxidizing agent to said 3-(((5(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazol-4-yl)methyl)thio)-5,5-dimethyl-4,5-dihydroisoxazole is in the range of 2:1 to 5:

1. Petition 870250090171, dated 03 / 10 / 2025, p. 59 / 60