Method for preparing 2-substituted aryl acetonitrile compound and use thereof

Abstract

The present invention provides a method for preparing a 2-substituted aryl acetonitrile compound and use thereof. The method prepares the 2-substituted aryl acetonitrile compound by means of a direct reaction under the action of a base with a substituted benzene and a 2-cyanocarboxylate as the starting materials. The reaction formula is as follows. Compared with the prior art, the method provided by the present invention features a high yield and the absence of transition metal catalysts, strong bases, or harsh reaction conditions.

Description

(trifluoromethyl)phenylethanone is a key intermediate in preparation of fungicide mefentrifluconazole (CN 105152899). Therefore, it is of great significance to provide a simple and efficient method to prepare 2-substituted arylacetonitrile compounds. The first synthetic method for 2-substituted arylacetonitrile compounds is performed through alkylation reaction of arylacetonitriles. The synthesis of the starting material arylacetonitriles in this method usually uses highly toxic cyanide, such as potassium cyanide. In addition, such method is easy to stop at the desired monoalkylated product, and the reaction may continuously occur to obtain a dialkylated product. For example, WO 2016037578 reported that the main product is 2,2-dimethyl-(2’-trifluoromethyl)     phenylacetonitrile in the reaction of 2- (trifluoromethyl)phenylacetonitrile with iodomethane in the presence of sodium hydride, shown as Reaction Scheme 1: Reaction Scheme 1 CN105753685 disclosed a second method for the preparation of the 2-substituted 1 arylacetonitrile compounds. This method uses ethyl 2-cyano-2-phenylacetate as starting material. Methyl 2-cyano-2-phenylacetate 2-cyano-2-phenylacetate undergoes first methylation reaction using dimethyl sulfate, and then decarboxylation in the presence of sodium methoxide to provide product, shown as Reaction Scheme 2: (this method has a complicated process) Reaction Scheme 2. Wang et al. reported a third method for the preparation of 2-substituted arylacetonitrile compounds (Adv. Synth. Catal. 2016, 358, 940-946).This method uses 2-cyanocarboxylate as starting material. 2-Cyanocarboxylate reacts with diphenyl iodonium salt first, followed by decarboxylation in the presence of base to provide the 2-substituted arylacetonitrile compound, shown as Reaction Scheme 3. This method requires expensive diphenyl iodonium salt. Its atomic efficiency is poor, and its cost is high. It is not amenable for large scale production: CN                 CN Reaction Scheme 3. Ma et al. reported a fourth method for the preparation of 2-substituted arylacetonitrile compounds (Angew. Chern. Int. Ed. 2021, 60, 7082-7086). This method uses 2-cyanocarboxylate as starting material. 2-Cyanocarboxylate and aryl bromide undergo coupling reaction in the presence of cuprous catalyst and ligand, and subsequent decarboxylation to afford the 2-substituted arylacetonitrile compound, shown as Reaction Scheme 4. Such method avoids the shortcoming of using expensive diaryliodonium salts, however it requires transition metal catalysts, specific ligands, and strong bases such as sodium tert-butoxide, in addition to extending the reaction time up to 24 hours. a Br Ar-" CN CuBr Ligand R COOEt Sodium terf-butoxide Isopropyl alcohol R Reaction Scheme 4 During the course of developing efficient method for the preparation of 2- substituted arylacetonitrile compounds, the inventors surprisingly discovered that 2-cyanocarboxylate and halogenated benzene or phenyl arylsulfonate compound undergo one step reaction in the presence of base to provide directly the target 2-substituted arylacetonitrile compounds in high yield, thus eliminating the use of CuBr ligand as catalyst in the aforementioned technical protocol. SUMMARY This application provides a method for preparing a 2-substituted arylacetonitrile compound of formula (1), comprising: reacting a substituted aromatic compound of formula (2), a 2-cyanocarboxylate compound of formula (3) in the presence of a base to obtain the 2-substituted arylacetonitrile compound (1), as shown in the following reaction scheme 5: Reaction Scheme 5 wherein R1 is a carbon-based group. In some embodiments, R1 is selected from the group consisting of Ci-Cio alkyl, C6-C12 aryl, and a heteroaryl group containing one or two atoms selected from nitrogen, oxygen and sulfur; wherein the alkyl, the aryl and the heteroaryl group are unsubstituted or substituted by halogen. Preferably, R1 is C1-C4 alkyl, wherein the C1-C4 alkyl is unsubstituted or substituted by halogen. R2, R3, R4, R5, and R6 are independently selected from the group consisting of 3 hydrogen, Ci-Cio alkyl, C6-C12 aryl, a heteroaryl group containing one or two atoms selected from nitrogen, oxygen and sulfur, halogen, nitro, a cyano group, a C1-C6 alkylacyl group, a C1-C6 alkoxy group, a C6-C12 aryloxy group and -COOR8, wherein the alkyl, the aryl and the heteroaryl group are unsubstituted or substituted with halogen; or, any two adjacent groups of R2, R3, R4, R5, and R6 together form a C1-C10 cyclic substituent; the C1-C10 cyclic substituent is free of heteroatoms or containing one or two atoms selected from nitrogen, oxygen and sulfur; and the cyclic substituent is unsubstituted or substituted with halogen; at least one of R2, R4 and R6 is selected from the group consisting of a haloalkyl group, nitro, a cyano group, halogen, a C1-C6 alkyl-acyl group and -COOR8. In some embodiments, R2 and R4 are independently selected from the group consisting of a C1-C4 haloalkyl group, nitro, a cyano group, a C2-C4 alkyl-acyl group and -COOR8; R3, R5, and R6 are independently selected from the group consisting of hydrogen and C1-C4 alkyl; R8 is C1-C4 alkyl or a C1-C2 haloalkyl group; and R7 is selected from the group consisting of hydrogen, C1-C10 alkyl, C6-C12 aryl, and a heteroaryl group containing one or two atoms selected from nitrogen, oxygen and sulfur; and the alkyl, the aryl and the heteroaryl group is unsubstituted or substituted by halogen. R8 is a carbon-based group, preferably selected from the group consisting of Ci-C10 alkyl, C6-C12 aryl, and a heteroaryl group containing one or two atoms selected from nitrogen, oxygen and sulfur, wherein the alkyl, the aryl, and the heteroaryl group are unsubstituted or substituted by halogen. Preferably, R8 is C1-C4 alkyl or a C1-C2 haloalkyl group. X1 is halogen or -OSO2R9; wherein R9 is selected from the group consisting of Ci-C10 alkyl, C6-C12 aryl, and a heteroaryl group containing one or two atoms selected from nitrogen, oxygen and sulfur, wherein the alkyl, the aryl and the heteroaryl group is unsubstituted or substituted by halogen; and the base is selected from the group consisting of an alkali metal carbonate, an alkali 4 metal bicarbonate, an alkali metal phosphate, an alkali metal hydroxide, an alkali metal alcoholate, an alkali metal hydride, an alkali metal Ci-Cb alkyl carboxylate, an alkali metal formate, an alkaline earth metal carbonate, an alkaline earth metal bicarbonate, an alkaline earth metal phosphate, an alkaline earth metal hydroxide, an alkaline earth metal alcoholate, an alkaline earth metal hydride, an alkaline earth metal Ci-Cb alkyl carboxylate, an alkaline earth metal formate, an alkali metal alkylide, an alkali metal amide, an organic amine compound, and a combination thereof. In some embodiments, the base is selected from the group consisting of an alkali metal carbonate, an alkali metal bicarbonate, an alkali metal phosphate, an alkali metal hydroxide, an alkali metal Ci-Cb alkyl carboxylate, an alkali metal formate, a tertiary amine compound, and a combination thereof; and the tertiary amine compound comprises a substituted or unsubstituted pyridine compound. In some embodiments, the base is selected from the group consisting of potassium carbonate, potassium hydroxide, sodium carbonate, sodium hydroxide, an alkyl tertiary amine compound (comprising a cyclic tertiary alkylamine compound) and a combination thereof; wherein alkyl is a C1-C12 alkyl, preferably a C1-C6 alkyl. In some embodiments, a molar ratio of the compound (3) to the compound (2) is (0.7-3.5): 1. In some embodiments, the molar ratio of the compound (3) to the compound (2) is (1.4-2.2):1, preferably (1.6-1.8):1. In some embodiments, the molar ratio of the compound (3) to the compound (2) is 3.5:1, 3.0:1, 2.5:1, 2.4:1, 2.3:1, 2.2:1, 2.1:1, 2.0:1, 1.9:1, 1.8:1, 1.7:1, 1.6:1, 1.5:1, 1.4:1, 1.3:1, 1.2:1, 1.1:1, 1.0:1, 0.9:1, 0.8:1, or 0.7:1. In some embodiments, a molar ratio of the compound (3) to the base is 1 :(0.3-2.0), preferably 1:(0.7-2.0), and more preferably 1:(0.9-1.1). In some embodiments, the molar ratio of the compound (3) to the base is 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1.0, 1:1.1, or 1:2.0. The reaction can be performed in the presence of a solvent. The solvent is selected from the group consisting of nitrile, ester, alkyl halide, ether, aromatic hydrocarbon, tertiary amine, amide, sulphone, sulfoxide, water, alcohol, ketone, and a combination thereof. In some embodiments, the solvent is selected from the group consisting of amide, sulphone, sulfoxide, water, and a combination thereof. Preferably, the solvent is selected from the group consisting of A; AAlimcthylformamidc, N-methylpyrrolidone, N,N-dimethylacetamide, dimethyl sulfoxide, water, and a combination thereof. The reaction can be performed without the presence of a solvent. The reaction is performed at -20-150°C, preferably 20-100°C, and more preferably 50-80°C. It should be noted that unless otherwise stated, terms “comprise”, “include” and any variations thereof, are intended to cover non-exclusive inclusion, for example, other elements that are not explicitly listed or inherent may also be included in addition to the series of elements listed. Unless otherwise specified, the term “or” is non-exclusive. For example, “A or B” includes “A is true (or exists) and B is false (or does not exist)”, “A is false (or does not exist) and B is true (or exists)”, and “both A and B are true (or exist)”. The carbon group is a positive monovalent group including a carbon atom. The carbon group is connected to other parts of the chemical structure through a carbon atom. The carbon group can be saturated, unsaturated (including aryl), chain, cyclic (including polycyclic), and can includes heteroatoms. Although the carbon group is not limited in size, usually, it includes 1-16 carbon atoms and 0-3 heteroatoms. Key carbon group is C1-C6 alkyl, C1-C4 haloalkyl, or phenyl substituted with 1-3 substituents selected from C1-C3 alkyl, halogen and nitryl. The alkyl may be linear or branched. The halogen includes fluorine, chlorine, bromine and iodine. In addition, regarding haloalkyl, alkyl therein may be partially or completely substituted by halogen atoms which may be the same or different. For example, haloalky is F3C, CICH2, CF3CH2 or CF3CCI2. In some embodiments, the method is performed in the presence of the base and solvent. The 2-cyanocarboxylate compound (3) and the substituted aromatic compound (2) undergo substitution and decarboxylation to obtain the compound (1). In a second aspect, this application provides a use of the method in the preparation of a triazole fungicide, where the triazole fungicide is selected from the group consisting of mefentrifluconazole, Ipfentrifluconazole, epoxiconazole, flutriafol, cyproconazole, 6 bromuconazole, difenoconazole, propiconazole, etaconazole and hexaconazole. Compared to the prior art, this application has the following beneficial effects. The method has readily-available raw materials. The substitution and decarboxylation are carried out in a simplified “one-step” manner. In addition, it does not require transition metal catalysts and ligands. The substituted aromatic compound (2) can be prepared according to the existing method, such as Basic Organic Chemistry (fourth edition), Sections 16.4, 18.8 and 18.9 Xing Qiyi et al. The 2-cyanocarboxylate compound (3) can be prepared according to the existing method, such as Organic & Biomolecular Chemistry (2017), 15(11), 23762384. DETAILED DESCRIPTION OF EMBODIMENTS This application will be described in detail below with reference to the embodiments to make objects, technical features and advantages of this application clearer, but these embodiments are not intended to limit the scope of this application. Example 1 Preparation of 2-(4-nitro-2-(trifluoromethyl)phenyl)propionitrile To a 100 mL reaction flask were sequentially added 5.1 g of ethyl 2-cyanopropionate, 5.5 g of potassium carbonate, 20 mL of A; AMimcthyl formamide and 5 g of 2-trifluoromethyl-4-nitrochlorobenzene. The reaction mixture was heated in a 65°C oil bath, reacted at 65°C for 6 h, cooled and added into 100 mL of methylbenzene. The resultant reaction solution was washed, concentrated and purified to obtain 4.7 g of 2-(4-nitro-2-(trifluoromethyl)phenyl)propionitrile (87% yield). 'H NMR (CDC13, 500 MHz, TMS): 5 8.58 (d, J= 2 Hz, 1H), 8.51 (dd, Ji = 8.5 Hz, J2 = 2 Hz, 1H), 8.00 (d,J=8.5Hz, 1H), 4.38 (q, J= 7 Hz, 1H), 1.72 (d,J=7Hz, 3H). 13C NMR (CDCI3, 125 MHz): 5 147.3, 142.9, 131.0, 129.1 (q, J= 33 Hz), 127.6, 122.6 (q, J=273 Hz), 122.1 (q, J= 5 Hz), 119.9, 28.1,21.9. Example 2 Preparation of 2-(4-nitro-2-(trifluoromethyl)phenyl)propionitrile To a 100 mL reaction flask were sequentially added 51 g of ethyl 2- cyanopropionate, 4.5 g of triethylenediamine, 55 g of potassium carbonate, 200 mL of dimethyl sulfoxide and 50 g of 2-trifluoromethyl-4-nitrochlorobenzene. The reaction mixture was heated in an 80°C oil bath, reacted at 80°C for 5 h, desolventized under reduced pressure, and added into 200 mL of methylbenzene. The resultant reaction solution was washed, concentrated and purified to obtain 46 g of 2-(4-nitro-2-(trifluoromethyl)phenyl)propionitrile (85% yield). Example 3 Preparation of 2-(4-nitro-2-(trifluoromethyl)phenyl)propionitrile To a 100 mL reaction flask were sequentially added 5.6 g of ethyl 2-cyanopropionate, 4.7 g of sodium carbonate, 5 g of l-chloro-2-(trifluoromethyl)-4-nitrobenzene and 10 mL of N-methylpyrrolidone. The reaction mixture was heated in a 50°C oil bath, reacted at 50°C for 5 h, cooled and added into 100 mL of methylbenzene. The resultant reaction solution was washed, concentrated and purified to obtain 5 g of 2-(4-nitro-2-(trifluoromethyl)phenyl)propionitrile (92% yield). Example 4 Preparation of 2-(4-nitro-2-(trifluoromethyl)phenyl)propionitrile To a 100 mL reaction flask were sequentially added 5.1 g of ethyl 2-cyanopropionate, 5.5 g of potassium carbonate, 0.2 g of copper(I) bromide (CuBr), 20 mL of ALV<limcthyl formamide and 5 g of l-chloro-2-(trifluoromethyl)-4-nitrobenzene. The reaction mixture was heated in a 65°C oil bath, reacted at 65°C for 6 h, cooled and added into 100 mL of methylbenzene. The resultant reaction solution was washed, concentrated and purified to obtain 3.1 g of 2-(4-nitro-2-(trifluoromethyl)phenyl)propionitrile (57% yield). Example 5 Preparation of 2-(5-methyl-2,4-dinitrophenyl)propionitrile To a 50 mL reaction flask were sequentially added 5 mL of dimethyl sulfoxide, 0.5 g of 5-chloro-2,4-dinitrotoluene, 0.53 g of ethyl 2-cyanopropionate, and 0.38 g of triethylenediamine. The reaction mixture was heated to 60°C, reacted at 60°C for 6 h, cooled and added into 50 mL of methylbenzene. The resultant reaction solution was washed, concentrated and purified to obtain 0.41 g of 2-(5-methyl-2,4-8 dinitrophenyl)propionitrile (76% yield). Example 6 Preparation of 2-(4-acetyl-2-nitrophenyl)propiononitrile To a 50 mL reaction flask were sequentially added 10 mL of N,N-dimethylformamide, 2 g of 4-chloro-3-nitroacetophenone, 2.3 g of ethyl 2-cyanopropionate and 2.5 g of potassium carbonate. The reaction mixture was heated to 60°C, reacted at 60°C for 5 h, cooled and added into 50 mL of methylbenzene. The resultant reaction solution was washed, concentrated and purified to obtain 1.7 g of 2-(4-acetyl-2-nitrophenyl)propiononitrile (78% yield). 'H NMR (CDC13, 500 MHz, TMS): 5 8.58 (d, J= 1.5 Hz, 1H), 8.27 (dd, Ji = 8.5 Hz, / 2 =1.5 Hz, 1H), 7.95 (d, / =8.5 Hz, 1H), 4.80 (q, / =7Hz, 1H), 2.69 (s, 3H), 1.75 (d, / = 7 Hz, 3H). 13C NMR (CDCI3, 125 MHz): 8 194.8, 147.6, 137.8, 136.4, 133.2, 130.3, 125.2, 120.0, 28.2, 26.6, 21.0. Example 7 Preparation of 2-(l-cyanoethyl)-5-nitrobenzonitrile To a 50 mL reaction flask were sequentially added 12 mL of N,N-dimethylformamide, 2 g of 2-chloro-5-nitrobenzonitrile, 2.5 g of ethyl 2-cyanopropionate and 2.7 g of potassium carbonate. The reaction mixture was heated to 60°C, reacted at 60°C for 5 h, cooled and added into 50 mL of methylbenzene. The resultant reaction solution was washed, concentrated and purified to obtain 1.66 g of 2-(1-cyanoethy 1)-5-nitrobenzonitrile (76% yield). ’H NMR (CDCI3, 500 MHz, TMS): 8 8.58 (d, / = 2.5 Hz, 1H), 8.54 (dd, Ji = 9.0 Hz, / 2 = 2.5 Hz, 1H), 7.98 (d, / = 9.0 Hz, 1H), 4.45 (q, / = 7.5 Hz, 1H), 1.78 (d, / = 7.5 Hz, 3H). 13C NMR (CDCI3, 125 MHz) 8 147.5, 147.0, 129.3, 128.5, 128.4, 118.8, 114.5, 112.9,30.3,20.8. Example 8 Preparation of 2-(4-nitro-2-(trifluoromethyl)phenyl)-3-methylbutanenitrile To a 100 mL reaction flask were sequentially added 6 g of ethyl 2-cyano-3-methylbutanoate, 5 g of l-chloro-2-(trifluoromethyl)-4-nitrobenzene, 5 g of potassium 9 carbonate and 20 mL of N, AMimcthylformamide. The reaction mixture was heated to 100°C, reacted at 100°C for 20 h, cooled and added into 100 mL of methylbenzene. The resultant reaction solution was washed, concentrated and purified to obtain 5 g of 2-(4-nitro-2-(trifluoromethyl)phenyl)-3-methylbutanenitrile (83% yield). Example 9 Preparation of ethyl 2-(l-cyanoethyl)-5-nitrobenzoate To a 50 mL reaction flask were sequentially added 12 mL of dimethylsulfoxide, 2 g of ethyl 2-chloro-5-nitrobenzoate, 2.0 g of ethyl 2-cyanopropionate and 2.2 g of potassium carbonate. The reaction mixture was heated to 60°C, reacted at 60°C for 10 h, cooled and added into 50 mL of methylbenzene. The resultant reaction solution was washed, concentrated and purified to obtain 2 g of 2-(l-cyanoethylamino)-5-nitrobenzoate (92% yield). 'H NMR (CDC13, 500 MHz, TMS): 5 8.84 (d, J= 2.5 Hz, 1H), 8.43 (dd, Ji = 9.0 Hz, J2 = 2.5 Hz, 1H), 7.94 (d, J= 9.0 Hz, 1H), 5.27 (q, J= 7.0 Hz, 1H), 4.46 (q, J= 7.0 Hz, 2H), 1.69 (d, J = 7.0 Hz, 3H), 1.47 (t, J= 7.0 Hz, 3H). 13C NMR (CDCI3,125 MHz): 8 164.4, 147.2, 145.7, 129.9, 129.3, 127.2, 126.3, 120.8, 62.4, 28.4, 21.3, 14.0. Example 10 Preparation of 4-(l-cyanoethyl)-3-nitrobenzotrifluoride To a 50 mL reaction flask were sequentially added 12 mL of N,N-dimethylformamide, 2 g of 4-chloro-3-nitrobenzotrifluoride, 2.0 g of ethyl 2-cyanopropionate and 2.2 g of potassium carbonate. The reaction mixture was heated to 60°C, reacted at 60°C for 10 h, cooled and added into 50 mL of methylbenzene. The resultant reaction solution was washed, concentrated and purified to obtain 1.5 g of 4-(l-cyanoethylamino)-3-nitrobenzotrifluoride (70% yield). ’H NMR (CDCI3, 500 MHz, TMS): 8 8.33 (s, 1H), 8.01 (s, 2H), 4.82 (q, J= 7.0 Hz, 1H), 1.76 (d,J=7.0 Hz, 3H). 13C NMR (CDCI3, 125 MHz): 8 198.4, 145.6, 140.9, 132.8 (q,J= 34 Hz), 130.9 (q,J=4Hz), 128.3, 122.3 (q,J=271Hz), 121.7 (q,J=4 Hz), 29.9. Example 11 Preparation of 2-(4-nitro-2-(trifluoromethyl)phenyl)-3- 10 phenylpropanenitrile To a 50 mL reaction flask were sequentially added 6 mL of N,N-dimethylformamide, 1 g of 2-chloro-5-phenylpropanenitrile, 1.6 g of ethyl 2-cyanophenylpropionate and 1.1 g of potassium carbonate. The reaction mixture was heated to 60°C, reacted at 60°C for 6 h, cooled and added into 50 mL of methylbenzene. The resultant reaction solution was washed, concentrated and purified to obtain 1.25 g of 2-(4-nitro-2-(trifluoromethyl)phenyl)-3-phenylpropanenitrile (88% yield). 'H NMR (CDC13, 500 MHz, TMS): 5 8.59 (d, J= 2.0 Hz, 1H), 8.43 (dd, Ji = 9.0 Hz, J2 = 2.0 Hz, 1H), 7.83 (d, J= 9.0 Hz, 1H), 7.37-7.28 (m, 5H), 4.52-4.49 (dd, Ji = 9.5 Hz, J2 = 4.5 Hz, 1H), 3.24 (dd, Ji = 14 Hz, J2 = 4.5 Hz, 1H), 3.11 (dd, Ji = 14 Hz, J2 = 9.5 Hz, 1H). Example 12 Preparation of l-(4-nitro-2-(trifluoromethyl)phenyl)ethan-l-one To a 50 mL reaction flask were sequentially added 1.1 g of potassium carbonate, 2.2 g of water, 1 g of 2-(4-nitro-2-(trifluoromethyl)phenyl)propionitrile, 0.1 g of copper(I) chloride and 10 mL of A; AMimethyl formamide, and the atmosphere in the reaction flask was replaced with oxygen atmosphere. The reaction mixture was heated in a 60°C oil bath, reacted at 60°C for 2 h, cooled and added into 50 mL of methylbenzene. The resultant reaction solution was washed, concentrated and purified to obtain 0.9 g of l-(4-nitro-2-(trifluoromethyl)phenyl)ethan-l-one (94% yield). ’H NMR (CDCI3, 500 MHz, TMS): 5 8.58 (d, J= 1.5 Hz, 1H), 8.48 (dd, Ji = 8.5 Hz, J2 = 1.5 Hz, 1H), 7.66 (d, J = 8.5 Hz, 1H), 2.63 (s, 3H). 13C NMR (CDCI3, 125 MHz): 8 199.8, 148.2, 145.7, 128.5 (q, J= 33 Hz), 128.4, 126.9, 122.3 (q, J= 273 Hz), 122.3 (q, J= 6 Hz), 30.5. Example 13 Preparation of l-(4-(4-chlorophenoxy)-2-(trifluoromethyl)phenyl)ethan-l-one To a 25 mL reaction flask were sequentially added 0.5 g of l-(4-nitro-2-(trifluoromethyl)phenyl)ethan-l-one, 0.3 g of 4-chlorophenol, 0.2 g of potassium carbonate and 2.5 mL of ALV-dimcthyl formamide. The reaction mixture was heated in 11 a 125°C oil bath, reacted at 125°C for 5 h, cooled and added into 50 mL of methylbenzene. The resultant reaction solution was washed, concentrated and purified to obtain 0.57 g of l-(4-(4-chlorophenoxy)-2-(trifluoromethyl)phenyl)ethan-l-one (85% yield). Example 14 Preparation of mefentrifluconazole To a 50 mL three-necked flask were sequentially added 0.7 g of water and 3.9 g of dimethyl sulfate. The reaction mixture was heated to 3 3 °C, drop wise added with 2.0 g of dimethyl sulfide, stirred for 15 min and added with 6.3 g of l-(4-nitro-2-(trifluoromethyl)phenyl)ethan-l-one prepared in Example 12 at 35°C. Then, the reaction mixture was added with 4.5 g of a 85 wt.% potassium hydroxide solution at 35-45°C under stirring, and stirred at 38°C for 2 h until raw materials were confirmed to be completely consumed. After that, the reaction mixture was added with 30 g of water at 60°C, and stirred for 20 min, and an organic phase was collected. The organic phase was dissolved in 30 g of dimethyl formamide (DMF), and subjected to distillation to remove dimethyl sulfide to obtain a DMF solution of 2-[4-(4-chlorophenoxy)-2-(trifluoromethyl) phenyl] -2-methyloxiran, which was further analyzed by high performance liquid chromatography (HPLC). The results demonstrated that 6.6 g of the product of interest (99% yield) was obtained. The DMF (30 g) solution of 2-[4-(4-chlorophenoxy)-2-(trifluoromethyl) phenyl]-2-methyloxiran (6.6 g) was heated to 60°C, sequentially added with 1.7 g of 99 wt.% 1,2,4-triazole and 0.3 g of sodium hydroxide powder under stirring, heated to 125°C and reacted at 125°C under stirring for 5 h until raw materials were confirmed to be completely consumed. The reaction mixture was evaporated under reduced pressure to remove most of the DMF, added with 30 g of methylbenzene and 20 g of water, and subjected to separation at 60°C to collect a methylbenzene phase. The methylbenzene phase was washed with 20 g of water, and subjected to separation to collect a methylbenzene solution. The methylbenzene solution was concentrated under reduced pressure to obtain a solution containing about 50 wt.% of the desired product. The solution was heated (about 80°C) for dissolution, slowly cooled to 0°C under stirring, 12 stirred at 0°C for 30 min, and filtered under vacuum to collect a filter cake. The filter cake was washed twice with 10 g of methylbenzene which was pre-cooled to 0°C, and dried to obtain 6.6 g of mefentrifluconazole (84% yield). Described above are merely illustrative of the disclosure, and are not intended to 5 limit the disclosure. Although the disclosure has been illustrated and described in detail above, it should be understood that those skilled in the art could still make modifications and replacements content to the embodiments content of the disclosure. Those modifications and replacements content made by those skilled in the art based on the content disclosed herein without departing from the scope of the disclosure shall fall 10 within the scope of the present disclosure defined by the appended claims.

Claims

1. A method for preparing a compound of formula (1), comprising:reacting a compound (2) with a compound (3) in the presence of a base to obtain the compound (1), as shown in the following reaction scheme:wherein R1 is a carbon-based group;R2, R3, R4, R5, and R6 are independently selected from the group consisting of hydrogen, Ci-Cio alkyl, C6-C12 aryl, a heteroaryl group containing one or two atoms selected from nitrogen, oxygen and sulfur, halogen, nitro, a cyano group, a Ci-Ce alkylacyl group, a Ci-Ce alkoxy group, a C6-C12 aryloxy group and -COOR8, wherein the alkyl, the aryl and the heteroaryl group are unsubstituted or substituted with halogen; or, any two adjacent groups of R2, R3, R4, R5, and R6 together form a C1-C10 cyclic substituent; the C1-C10 cyclic substituent is free of heteroatoms or containing one or two atoms selected from nitrogen, oxygen and sulfur; and the cyclic substituent is unsubstituted or substituted with halogen;at least one of R2, R4 and R6 is selected from the group consisting of a C1-C4 haloalkyl group, nitro, a cyano group, halogen, a Ci-Ce alkyl-acyl group and -COOR8; wherein R8 is a carbon-based group;R7 is selected from the group consisting of hydrogen, C1-C10 alkyl, C6-C12 aryl, and a heteroaryl group containing one or two atoms selected from nitrogen, oxygen and sulfur; and the alkyl, the aryl and the heteroaryl group is unsubstituted or substituted by halogen;X1 is halogen or -OSO2R9; wherein R9 is selected from the group consisting of Ci-C10 alkyl, C6-C12 aryl, and a heteroaryl group containing one or two atoms selected from nitrogen, oxygen and sulfur, wherein the alkyl, the aryl and the heteroaryl group isunsubstituted or substituted by halogen; andthe base is selected from the group consisting of an alkali metal carbonate, an alkali metal bicarbonate, an alkali metal phosphate, an alkali metal Ci-Cb alkyl carboxylate, an alkali metal formate, an alkali metal hydroxide, an alkali metal alcoholate, an alkali metal hydride, an alkaline earth metal carbonate, an alkaline earth metal bicarbonate, an alkaline earth metal phosphate, an alkaline earth metal Ci-Cb alkyl carboxylate, an alkaline earth metal formate, an alkaline earth metal hydroxide, an alkaline earth metal alcoholate, an alkaline earth metal hydride, an alkali metal alkylide, an alkali metal amide, an organic amine compound, and a combination thereof.

2. The method according to claim 1, characterized in that the base is selected from the group consisting of an alkali metal carbonate, an alkali metal bicarbonate, an alkali metal phosphate, an alkali metal hydroxide, an alkali metal Ci-Cb alkyl carboxylate, an alkali metal formate, a tertiary amine compound, and a combination thereof.

3. The method according to claim 2, characterized in that the base is selected from the group consisting of potassium carbonate, potassium hydroxide, sodium carbonate, sodium hydroxide and a tertiary amine compound; wherein the tertiary amine compound is an alkyl tertiary amine compound.

4. The method according to any one of claims 1-3, characterized in that R1 is selected from the group consisting of Ci-Cio alkyl, C6-C12 aryl, and a heteroaryl group containing one or two atoms selected from nitrogen, oxygen and sulfur; wherein the alkyl, the aryl and the heteroaryl group are unsubstituted or substituted by halogen;R2 and R4 are independently selected from the group consisting of a C1-C4 haloalkyl group, nitro, a cyano group, a C2-C4 alkyl-acyl group and -COOR8; wherein R8 is C1-C4 alkyl or a C1-C2 haloalkyl group; andR3, R5, and R6 are independently selected from the group consisting of hydrogen and C1-C4 alkyl.

5. The method according to claim 4, characterized in that R1 is C1-C4 alkyl; R2 is trifluoromethyl; R3, R5, and R6 are independently hydrogen; and R4 is nitro; andX1 is fluorine, chlorine, bromine or iodine.

6. The method according to claim 5, characterized in that X1 is chlorine.

7. The method according to claim 1, characterized in that a molar ratio of the compound (3) to the compound (2) is (0.7-3.5): 1; anda molar ratio of the compound (3) to the base is 1:(0.3-2.0).

8. The method according to claim 7, characterized in that the molar ratio of the compound (3) to the compound (2) is (1.4-2.2): 1; andthe molar ratio of the compound (3) to the base is 1:(0.7-2.0).

9. The method according to claim 1, characterized in that a molar ratio of the compound (3) to the compound (2) is (1.6-1.8): 1; anda molar ratio of the compound (3) to the base is 1:(0.9-1.1).

10. A use of the method according to claim 1 in the preparation of a triazole fungicide, characterized in that the triazole fungicide is selected from the group consisting of mefentrifluconazole, Ipfentrifluconazole, epoxiconazole, flutriafol, cyproconazole, bromuconazole, difenoconazole, propiconazole, etaconazole and hexaconazole.