Preparation method of pyroxasulfone

Abstract

The present invention relates to a process for preparing pyroxasulfone of formula (I) or a salt thereof from a compound of formula (II) by reacting the compound of formula (II) with a suitable oxidizing agent in the presence of a metal catalyst, a mineral acid and optionally a phase transfer catalyst. Formula (I) and formula (II).

Description

Technical Field

[0001] This invention relates to a novel method for preparing sulfonylpyrazine of formula (I) or its salts from compounds of formula (II).

[0002]

[0003] Equation (I) Equation (II) Background Technology

[0004] Sulfonazole is an isoxazoline herbicide that works by inhibiting very long chain fatty acid elongation enzymes (VLCFAEs). Its chemical name is [5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)1H-pyrazol-4-yl]methyl-4,5-dihydro-5,5-dimethylisoxazole-3-yl sulfone, and its CAS number is 447399-55-5. It is represented by compounds of formula (I):

[0005]

[0006] Formula (I)

[0007] Sulfonazole is a selective pre-emergence herbicide for weeds and broadleaf weeds. It is used to control barnyard grass, neem, Phyllanthus urinaria, Phalaenopsis orchid, barnyard grass, Celosia argentea, purslane, wrinkled amaranth, and long-flora amaranth in crops such as corn, wheat, and soybean.

[0008] Sulfonazole was first disclosed in US7238689. Patents US6841519 and IN220938 disclose intermediates and methods for preparing sulfonazole. The methods disclosed in the above patents can be described as follows:

[0009]

[0010] Using the above method, compound (II) can be converted into compound (I) by using an oxidant such as m-chloroperbenzoic acid (mCPBA). However, the use of this oxidant on a commercial scale presents problems such as waste management and low yield.

[0011] Another common oxidant is hydrogen peroxide. For example, refer to WO2022138781, which discloses the conversion of compound (II) to compound (I) in the presence of a base using hydrogen peroxide or a persulfate compound as an oxidant. However, the use of hydrogen peroxide in the presence of a base can lead to problems related to byproducts due to the non-selective oxidation of sulfur. This process lacks chemoselectivity.

[0012] Referring to WO2022191292, this application discloses a method for preparing a compound of formula (2), the method comprising reacting a compound of formula (1) with an oxidant in the presence of a gold catalyst and a carboxylic acid, wherein the reaction is carried out at a temperature above 35°C;

[0013]

[0014] The drawback of the above reaction scheme is the need for acid additives, such as carboxylic acids. In large-scale production processes, the use of carboxylic acids presents challenges for waste management. Wastewater treatment is required to neutralize residual carboxylic acids.

[0015] In addition to the high price of these organic acids, they also present problems related to contamination by harmful microorganisms during storage.

[0016] Reference was also made to WO2021002484, which discloses the conversion of compound (II) to compound (I) in the presence of hydrogen peroxide and a metal catalyst. The main drawback of this synthesis is the excessively long reaction time and the incomplete conversion of compound (II) to sulfonylpyrazol. Consequently, a considerable amount of impurities are obtained along with the difficult-to-separate sulfonylpyrazol.

[0017] Several drawbacks exist in known methods in this field, such as waste management, wastewater treatment, impurity profiles of concern in toxicology, and production costs. Wastewater treatment requires high energy consumption, and wastewater treatment plants also generate air pollutants. These problems make the entire process unsustainable and could potentially cause significant environmental harm.

[0018] Therefore, there is an urgent need in the art to develop a novel and improved method to overcome the shortcomings of existing technologies. This invention aims to address all the aforementioned problems related to waste management, synthesis costs, low reaction rates, non-selective oxidation, incomplete reactant conversion, low yields, and low purity. Therefore, this invention aims to provide a commercially viable, safer, more environmentally friendly, and sustainable method. Summary of the Invention

[0019] The main objective of this invention is to provide a method for preparing sulfonylpyrazol of formula (I) from a compound of formula (II) by using a suitable oxidizing agent in the presence of one or more suitable reactive chemicals.

[0020] Another major objective of this invention is to provide a method for obtaining sulfopyrazole of formula (I) in high yield.

[0021] Another major objective of this invention is to provide a simple, sustainable, cost-effective, environmentally friendly and commercially viable method for preparing sulfonylpyrazole of formula (I).

[0022] According to one aspect of the present invention, a method for preparing sulfonylpyrazol of formula (I) from a compound of formula (II) is provided, wherein the method comprises oxidizing the compound of formula (II) in the presence of one or more suitable reactive chemicals at a temperature range of 20 to 80°C.

[0023] According to one aspect of the invention, a method for preparing sulfonylpyrazol of formula (I) from a compound of formula (II) is provided, wherein the method comprises reacting the compound of formula (II) with an oxidant in the presence of a catalyst, an inorganic acid and optionally another phase transfer catalyst.

[0024] According to another embodiment of the present invention, the oxidant is selected from perboric acid, perborate, peracetic acid, hypochlorite (such as sodium hypochlorite, potassium hypochlorite), permanganate, manganese dioxide, etc.

[0025] According to yet another embodiment of the invention, the oxidant is not hydrogen peroxide.

[0026] According to another embodiment of the present invention, the catalyst is selected from metal catalysts.

[0027] According to yet another embodiment of the present invention, the acid is selected from inorganic acids. Detailed Implementation

[0028] Some representative embodiments of the present invention will be discussed below. The invention is not limited to the specific details and representative methods in its broader sense. This description is illustrative, combining the provided embodiments and methods with specific examples. The invention is particularly noted in all its aspects; please refer to this specification and its equivalents.

[0029] All technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this subject matter pertains. It should be noted that, as used in the specification, the singular forms “a,” “an,” and “described” include plural references unless the context clearly specifies otherwise. It should also be noted that, unless the content clearly states otherwise, the term “or” is generally used in its own sense, including “and / or”.

[0030] The terms "about" or "approximately" as used in this invention include the numerical values ​​and refer to an acceptable range of deviation from a particular value, determined by a person skilled in the art taking into account the measurement in question and the errors associated with the measurement of the particular quantity (i.e., limitations of the measurement system). For example, "about" may refer to a range of one or more standard deviations, or a range of ±10 or ±5 of the nominal value. Unless otherwise stated in this invention, the expression of numerical ranges is used only as a shorthand, and each individual numerical value is incorporated into the specification as if it were stated separately in this invention. The endpoints of all ranges are included within the range and can be combined independently. It should be understood that, when a parameter range is given, all integers within the range and their tenths are also included. For example, "0.1-80%" includes 0.1%, 0.2%, 0.3%, etc., up to a maximum of 80%.

[0031] The terms “comprising,” “including,” “having,” “containing,” “involving,” etc., used in this invention should be understood as open-ended, meaning they include but are not limited to.

[0032] The terms "preferred" and "ideal" refer to embodiments of the invention that may provide certain benefits in certain circumstances. In one embodiment, the aspects and embodiments described in the invention should also be interpreted as replacing the term "comprising" with "consisting of," "substantially composed of," or "essentially composed of."

[0033] Unless otherwise stated, the term "room temperature" generally refers to a temperature between 20 and 35°C.

[0034] The term "purity" refers to the purity determined by HPLC (high-performance liquid chromatography).

[0035] The term "sulfonylpyrazole" as used in this invention includes sulfonylpyrazole free base or salt thereof, and is used interchangeably throughout the disclosure.

[0036] Unless otherwise stated, the term "perboronic acid or its salt" as used in this invention is referred to as "PBS" and includes all possible forms, such as crystalline, hydrated, amorphous, anhydrous, etc.

[0037] The scope of this invention should not be limited to the specific embodiments described herein, which are for illustrative purposes only.

[0038] According to one aspect of the present invention, a method for preparing sulfonylpyrazol of formula (I) from a compound of formula (II) is provided, wherein the method comprises oxidizing the compound of formula (II) in the presence of one or more suitable reactive chemicals at a temperature range of 20 to 80°C.

[0039] According to one aspect of the invention, a method is provided for preparing sulfonylpyrazol of formula (I) from a compound of formula (II), wherein the method comprises reacting the compound of formula (II) with an oxidant in the presence of a catalyst, an inorganic acid, and optionally another phase transfer catalyst. According to one aspect of the invention, the optional phase transfer catalyst is preferably a quaternary ammonium salt.

[0040] Therefore, based on the present invention, sulfonylpyrazine of formula (I) can be easily and efficiently prepared from compound (II) by the following reaction scheme:

[0041] Reaction scheme I:

[0042]

[0043] According to the method of reaction scheme I, the oxidant is selected from perboric acid, perborate, peracetic acid, hypochlorite (such as sodium hypochlorite, potassium hypochlorite), permanganate, manganese dioxide, etc.

[0044] According to one embodiment of the present invention, the oxidant is preferably perboric acid or a salt of perboric acid, including its crystalline, amorphous, and anhydrous forms.

[0045] According to another embodiment of the present invention, perborate includes, but is not limited to, sodium perborate monohydrate trihydrate, sodium perborate or sodium perborate, sodium permetoborate, sodium peroxyborate, sodium perborate hexahydrate, sodium perborate monohydrate, sodium perborate tetrahydrate, etc.

[0046] According to yet another embodiment of the invention, the oxidant is a salt of perboric acid.

[0047] According to another preferred embodiment of the invention, the salt of perboric acid is sodium perborate or its hydrate.

[0048] Sodium perborate is well known to be used as a bleaching agent in the detergent industry. This crystallizing agent is economically available in hydrate form, represented by the general formula NaBO3•n H2O (n ranging from 1 to 4).

[0049] Sodium perborate can exist in anhydrous or hydrated forms. The hydrated form is freely soluble in water. The more common hydrate forms are sodium perborate monohydrate and sodium perborate tetrahydrate.

[0050] According to the method of reaction scheme I, the metal catalyst is selected from, but not limited to, tungsten catalysts, molybdenum catalysts, iron catalysts, manganese catalysts, vanadium catalysts, niobium catalysts, tantalum catalysts, titanium catalysts, zirconium catalysts, copper catalysts, thallium catalysts, etc., including their acid and salt forms.

[0051] According to another preferred embodiment of the present invention, the metal catalyst is a tungsten catalyst or a molybdenum catalyst.

[0052] According to another embodiment, preferred examples of tungsten catalysts include tungstic acid, tungstates such as sodium tungstate, including sodium tungstate dihydrate and sodium tungstate decahydrate, potassium tungstate, calcium tungstate, ammonium tungstate; metallic tungsten, tungsten oxide (such as tungsten oxide (VI), which is also called tungsten trioxide), tungsten carbide, tungsten chloride (such as tungsten chloride (VI), which is tungsten hexachloride), tungsten bromide (such as tungsten bromide (V)), tungsten sulfide (such as tungsten sulfide (IV), which is also called tungsten disulfide), phosphotungstic acid and its salts, such as phosphotungstic acid, sodium phosphotungstate, ammonium phosphotungstate, etc.; silicotungstic acid and its salts such as silicotungstic acid, sodium silicotungstate, etc.; and mixtures thereof. More preferably, sodium tungstate or sodium tungstate dihydrate.

[0053] According to yet another embodiment, preferred examples of molybdenum catalysts include molybdic acid, molybdates, molybdenum metal, molybdenum oxide, sodium molybdate, potassium molybdate, ammonium molybdate, molybdenum carbide, molybdenum chloride, molybdenum sulfide, molybdenum bromide, phosphomolybdic acid, sodium phosphomolybdate, ammonium phosphomolybdate, molybdic acid silicomolybdate, sodium molybdate silicomolybdate, and their salts and mixtures. More preferably, ammonium molybdate or molybdic acid.

[0054] According to the method of reaction scheme I, the inorganic acid is selected from hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, p-toluenesulfonic acid, etc.

[0055] According to another embodiment of the present invention, the inorganic acid is preferably sulfuric acid, hydrochloric acid, or p-toluenesulfonic acid.

[0056] In this method, inorganic acids are used instead of organic acids because they provide more stable and stronger acidic conditions, which are crucial for efficient oxidation reactions in the given method. Inorganic acids such as sulfuric acid, hydrochloric acid, and p-toluenesulfonic acid are generally more stable and do not introduce additional organic residues or byproducts that could complicate the purification of the final product. Furthermore, inorganic acids can effectively enhance the catalytic activity of the metal catalysts involved in the oxidation process, thereby improving the yield and purity of compound I (sulfonylpyrazol).

[0057] Other major disadvantages of using organic acids include high cost, susceptibility to contamination, and the need for wastewater treatment due to the environmental hazards of residual waste.

[0058] According to the method of Scheme I, the solvent is selected from tetrahydrofuran, chlorobenzene, dichlorobenzene, dichloromethane, methanol, ethanol, propanol, 2-propanol, butanol, sec-butanol, isobutanol, tert-butanol, sec-pentanol, acetonitrile, methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate and its isomers, N,N-dimethylformamide (DMF), etc.

[0059] According to another embodiment of the invention, the solvent is preferably acetonitrile or tetrahydrofuran.

[0060] According to reaction scheme I, the phase transfer catalysts that can be used are selected from quaternary ammonium salts such as tetrabutylammonium bromide, crown ethers, and phosphonium compounds.

[0061] In one embodiment, the sulfonylpyrazol prepared using the method of the present invention is substantially free of impurities.

[0062] One embodiment of the present invention provides sulfopyrazole of formula (I) with a purity greater than 95%, preferably greater than 99%.

[0063] One embodiment of the present invention provides sulfopyrazole of formula (I) with a yield of up to 96% or higher.

[0064] In another embodiment, sulfopyrazol prepared using the method disclosed in this invention is used to prepare agricultural chemical compositions or formulations.

[0065] Another embodiment of the invention is illustrated by the following examples included in the table. These examples are merely illustrative and are not intended to limit the scope of the invention. Certain modifications and equivalents will be apparent to those skilled in the art and are intended to be included within the scope of the invention.

[0066] Conventional methods for preparing sulfonylpyrazine of formula (I) from compound (II)

[0067] Sulfonylpyrazol of formula (I) can be prepared by reacting a compound of formula (II) with a suitable oxidant in the presence of a metal catalyst, an inorganic acid, and optionally a phase transfer catalyst, using the following conventional steps:

[0068] a) Load the selected oxidant in a predetermined amount at 25-30°C;

[0069] b) Add the selected solvent in a predetermined amount;

[0070] c) Add the predetermined amount of the selected inorganic acid at 25-30°C for 1 hour;

[0071] d) Continuously stir the mixture;

[0072] e) Add 1-2 grams of metal catalyst at 25-30°C, and optionally add 0.5-1 gram of phase transfer catalyst (preferably tetrabutylammonium bromide).

[0073] f) At 60-65°C, a predetermined amount of compound (II) is added to a predetermined amount of solvent solution within 4-6 hours;

[0074] g) After complete addition of compound (II), raise the temperature to 70-72°C; maintain the temperature for 16-20 hours.

[0075] h) Add sodium sulfite solution to the reactants (after the reactants have cooled to about 55°C) until the starch iodide test paper changes from blue to colorless.

[0076] i) Water is then added to the residue, and the pH is maintained at 7-8 using a caustic alkali or sodium hydroxide solution.

[0077] j) The filtered compound was washed with 10% sodium bicarbonate to obtain the final product of formula (I) in up to 99% yield.

[0078] Example

[0079] The following describes the method for preparing sulfopyrazazole (Formula I) from a compound of Formula II using the present invention and using hydrogen peroxide (as an oxidant) known in the art (comparative example).

[0080] Reaction Scheme II:

[0081]

[0082] Example 1: At 25-30°C, 42.8 g of sodium perborate tetrahydrate was placed in a 250 mL four-necked RBF (round-bottom flask). 200 mL of acetonitrile was added. 50 g of 30% sulfuric acid was added over 1 hour at 25-30°C with continuous stirring. 1 g of sodium tungstate was added at 25-30°C, and optionally 0.5 g of TBAB (tetrabutylammonium bromide) was added. The mixture was heated to 60-65°C. 50 g of compound (II) was added to 200 g of acetonitrile solution over 6 hours, and stirred at 60-65°C for 4 hours. Water was added and stirred for 30 minutes. The filtered wet filter cake was washed with 10% sodium bicarbonate. The final product of formula (I) with a purity of 99.7% was separated (yield: 96%).

[0083] Example 2: At 25-30°C, 42.8 g of sodium perborate monohydrate was placed in 250 mL of a four-necked RBF container. 200 mL of acetonitrile was added. 50 g of 30% sulfuric acid was added over 1 hour at 25-30°C with continuous stirring. 1 g of sodium tungstate was added at 25-30°C, and optionally 0.5 g of TBAB was added. The mixture was heated to 60-65°C. 50 g of compound (II) was added to 200 g of acetonitrile solution over 6 hours, and stirred at 60-65°C for 4 hours. Water was added and stirred for 30 minutes. The filtered wet filter cake was washed with 10% sodium bicarbonate. The final product of formula (I) with a purity of 99.7% was separated (yield: 96%).

[0084] Example 3: At 25-30°C, 47.1 g of sodium perborate tetrahydrate was added to a 250 ml four-necked RBF container. 125 ml of acetonitrile was added. 20 g of 30% hydrochloric acid was added over 1 hour while continuously stirring at 25-30°C. 1 g of sodium tungstate was added at 25-30°C, and optionally 0.5 g of TBAB was added. The mixture was heated to 60-65°C. 50 g of compound (II) was added to 300 g of acetonitrile solution over 6 hours, and stirred at 60-65°C for 4 hours. Water was added and stirred for 30 minutes. The filtered wet filter cake was washed with 10% sodium bicarbonate. The final product of formula (I) with a purity of 99.5% was separated (yield: 85%).

[0085] Example 4: At 25-30°C, 45 g of sodium perborate tetrahydrate was placed in a 250 ml four-necked RBF container. 125 ml of acetonitrile was added. Diluted p-toluenesulfonic acid (24 g) was added over 1 hour at 25-30°C with continuous stirring. 1 g of sodium tungstate was added at 25-30°C, and optionally 0.5 g of TBAB was added. The mixture was heated to 60-65°C. 50 g of compound (II) was added to 300 g of acetonitrile solution over 6 hours, and stirred at 60-65°C for 4 hours. Water was added and stirred for 30 minutes. The filtered wet filter cake was washed with 10% sodium bicarbonate. The final product of formula (I) with a purity of 99.3% was separated (yield: 80%).

[0086] Example 5: At 25-30°C, 47.1 g of sodium perborate tetrahydrate was added to a 250 ml four-necked RBF solution. 200 ml of acetonitrile was added. 40% H₂SO₄ (42.5 g) was added over 1 hour with continuous stirring at 25-30°C. 1 g of 85% molybdic acid was added as a catalyst at 25-30°C, and optionally 0.5 g of TBAB was added. The mixture was heated to 60-65°C. 50 g of compound (II) was added to 300 g of acetonitrile solution over 6 hours, and the mixture was stirred at 60-65°C for 4 hours. Water was added and stirred for 30 minutes. The filtered wet filter cake was washed with 10% sodium bicarbonate. The final product of formula (I) with a purity of 99.6% was separated (yield: 90%).

[0087] Example 6: At 25-30°C, 47.1 g of sodium perborate tetrahydrate was added to 250 ml of four-necked RBF solution. 150 g of tetrahydrofuran was added. 40% H2SO4 (42.5 g) was added over 1 hour at 25-30°C with continuous stirring. 1 g of sodium tungstate was added as a catalyst at 25-30°C, and optionally 0.5 g of TBAB was added. The mixture was heated to 60-65°C. 50 g of compound (II) was added to 150 ml of tetrahydrofuran solution over 6 hours, and the mixture was stirred at 60-65°C for 4 hours. Water was added and stirred for 30 minutes. The filtered wet cake was washed with 10% sodium bicarbonate. The final product of formula (I) with a purity of 99.6% was separated (yield: 91%).

[0088] Comparative Example 1: At 25-30°C, 39.4 g of hydrogen peroxide was added to 250 mL of a four-necked RBF solution. 200 mL of acetonitrile was added. 50 g of 30% sulfuric acid was added over 1 hour at 25-30°C with continuous stirring. 1 g of sodium tungstate was added as a catalyst at 25-30°C, and optionally 0.5 g of TBAB was added. The mixture was heated to 60-65°C. 50 g of compound (II) was added to 200 mL of acetonitrile solution over 6 hours, and the mixture was stirred at 60-65°C for 4 hours. Water was added and stirred for 30 minutes. The filtered wet filter cake was washed with 10% sodium bicarbonate. The final product of formula (I) with a purity of 97.8% was obtained (yield: 78%).

[0089] Comparative Example 2: At 25-30°C, 39.4 g of hydrogen peroxide was added to 250 mL of a four-necked RBF container. 150 mL of tetrahydrofuran was added. Diluted p-toluenesulfonic acid (20 g) was added over 1 hour at 25-30°C with continuous stirring. 1 g of sodium tungstate was added as a catalyst at 25-30°C, and optionally 0.5 g of TBAB was added. The mixture was heated to 60-65°C. 50 g of compound (II) was added to the 150 g tetrahydrofuran solution over 6 hours, and the mixture was stirred at 60-65°C for 4 hours. Water was added and stirred for 30 minutes. The filtered wet filter cake was washed with 10% sodium bicarbonate. The final product of formula (I) with a purity of 97.2% was separated (yield: 75%).

[0090] It was observed that using perborate as the oxidant led to a significant increase in the yield of sulfonylpyrazine. Furthermore, when combined with inorganic acids, it generates a powerful oxidizing medium for complete oxidation. Further addition of suitable metal catalysts, such as sodium tungstate or molybdate, can enhance selective sulfur oxidation.

[0091] Conversely, as shown in Comparative Examples 1 and 2, the use of hydrogen peroxide resulted in lower yields and relatively higher impurity levels. Hydrogen peroxide decomposes and leads to inconsistent oxidation and the formation of undesirable byproducts, resulting in a high impurity content in the final product. The results obtained in terms of yield and purity after using hydrogen peroxide and PBS in the presence of inorganic acids and metal catalysts are compared in the table below:

[0092] Table 1:

[0093]

[0094] Compared to hydrogen peroxide, the main advantage of using perborate in crystalline hydrate form as an oxidant is its higher oxidation potential and reactivity. Furthermore, PBS exhibits significantly lower toxicity and a longer shelf life compared to high-concentration hydrogen peroxide solutions, which can also pose a significant explosion hazard.

[0095] The inventors of this invention have discovered that, compared to hydrogen peroxide, sodium perborate crystals act as excellent oxidants even at low pH values. Sodium perborate hydrate is used to provide perborate anions in the reaction system for complete oxidation.

[0096] The differences in yield and purity of Formula I are shown in Table 1. Therefore, the preferred oxidant used in the oxidation of Formula II to obtain Formula I is perboric acid and its salt (PBS). Furthermore, sulfuric acid is preferred as an inorganic acid for obtaining higher yield and purity.

[0097] Table 2:

[0098]

[0099] Sodium perborate or its hydrate is a mild, inexpensive, and air-stable oxidant. Due to its high affinity for water, it is usually present in its hydrated form. The method of the present invention can selectively and efficiently oxidize sulfur in formula (II). In almost all cases, the method of the present invention improves the yield and purity of the product. The use of PBS in the presence of an inorganic acid (such as sulfuric acid, hydrochloric acid, or p-toluenesulfonic acid) and a suitable metal catalyst (such as sodium tungstate or molybdate) provides efficient oxidation in the oxidation of formula II to obtain sulfonylpyrazol of formula I, resulting in higher yields and purity.

[0100] Furthermore, the method described in this invention does not present any issues related to the neutralization of organic acid residues in the resulting effluent. Higher yields make the entire process more cost-effective and reduce waste management problems.

[0101] Therefore, the inventors of this invention have successfully developed a new and improved method for synthesizing sulfonylpyrazine of formula (I) from formula (II). Compared with methods known in the art, the method of this invention provides higher yields and lower impurity distribution. The method of this invention is simple, sustainable, efficient, improved, cost-effective, and commercially viable.

[0102] The preferred form of the invention has been described herein. Many alterations, modifications, and / or alternative applications of the invention will immediately become apparent to those skilled in the art. Therefore, it should be understood that, as stated above, the invention is not limited to the actual aspects of the preferred embodiments described herein, and any such modifications and variations must be considered within the spirit and scope of the invention.

Claims

1. A novel and improved method for preparing sulfonylpyrazol of formula (I) or its salts from compounds of formula (II), characterized in that, include: (I) (II) Compound (II) reacts with an oxidant in the temperature range of 20 to 80 °C in the presence of a metal catalyst, an inorganic acid, and an optional phase transfer catalyst.

2. The method according to claim 1, characterized in that, in, The oxidant is selected from perboric acid, perborates, peracetic acid, hypochlorites and their salts (such as sodium hypochlorite and potassium hypochlorite), permanganates and manganese dioxide.

3. The method according to claim 1, characterized in that, in, The metal catalyst is selected from tungsten catalysts, molybdenum catalysts, iron catalysts, manganese catalysts, vanadium catalysts, niobium catalysts, tantalum catalysts, titanium catalysts, zirconium catalysts, copper catalysts, and thallium catalysts, including their acid and salt forms.

4. The method according to claim 1, characterized in that, The inorganic acid is selected from hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, and p-toluenesulfonic acid.

5. The method according to claim 1, characterized in that, in, The solvent is selected from tetrahydrofuran, chlorobenzene, dichlorobenzene, dichloromethane, methanol, ethanol, propanol, 2-propanol, butanol, sec-butanol, isobutanol, tert-butanol, sec-pentanol, acetonitrile, methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate and its isomers, and N,N-dimethylformamide (DMF).

6. The method as described in claim 1, characterized in that, The optional phase transfer catalyst is selected from quaternary ammonium salts, crown ethers, and phosphonium compounds.

7. The sulfonylpyrazol of formula (I) prepared from a compound of formula (II) using the method described in the preceding claims is used to prepare an agrochemical composition or formulation.

Images