Preparation method of N-(2-cyanophenyl)-1, 1, 1-trifluoromethanesulfonamide

Abstract

The invention provides a method for preparing N-(2-cyanophenyl)-1, 1, 1-trifluoromethanesulfonamide as shown in a formula (I), which comprises the step of reacting 2-aminobenzonitrile with a compound as shown in a formula (II) in a solvent under the action of alkali. According to the method, the reaction is complete and clean, aftertreatment is easy, the prepared N-(2-cyanophenyl)-1, 1, 1-trifluoromethanesulfonamide is high in yield and purity, and only sodium chloride serves as a byproduct. # imgabs0 #

Description

Technical Field

[0001] The invention belongs to the field of pesticides, and specifically relates to a method for preparing N-(2-cyanophenyl)-1,1,1-trifluoromethanesulfonamide. Background Art

[0002] N-(2-cyanophenyl)-1,1,1-trifluoromethanesulfonamide, CAS No: 53718-42-6 (Formula I), is a key intermediate of the new herbicide Dimesulfazet produced by Nissan Chemical, and its structural formula is shown in Formula I below:

[0003]

[0004] Dimesulfazet is a trifluoromethylsulfonamide herbicide developed by Nissan Chemical Co. Ltd., CAS registration number 1215111-77-5, development code NC-653, molecular formula C 13 H 15 F 3 N 2 O 3 S, the structural formula is as follows:

[0005]

[0006] In patent application WO2015060402A1 (International Publication Date: 2015-04-30), Nissan Chemical Co. Ltd. reported that the synthesis route of the compound of formula I is as follows:

[0007]

[0008] In addition, in patent application JP2020023443A (publication date: 2020-02-13), Nissan Chemical Co. Ltd. also reported the synthesis route of the compound of formula I as follows:

[0009]

[0010] In the above two patent applications, the synthesis of the compound of formula I uses an expensive reagent trifluoromethanesulfonic anhydride (CAS No: 358-23-6). In addition, when trifluoromethanesulfonic anhydride is used as a reaction reagent, trifluoromethanesulfonic acid or its salt is generated as a by-product, which poses a severe challenge to the treatment of three wastes. Summary of the invention

[0011] The object of the present invention is to provide a method for preparing N-(2-cyanophenyl)-1,1,1-trifluoromethanesulfonamide represented by formula (I), which comprises the steps of reacting 2-aminobenzonitrile with a compound of formula (II) in a solvent under the action of a base:

[0012]

[0013] In formula (II), R is selected from F, Cl and Br.

[0014] In some embodiments, in Formula (II), R is selected from Cl and Br.

[0015] In some embodiments, R is Cl.

[0016] In some embodiments, the base is selected from one or more of 4-dimethylaminopyridine, triethylamine, and diisopropylethylamine.

[0017] In some embodiments, the base is 4-dimethylaminopyridine;

[0018] In some embodiments, the molar ratio of the base to 2-aminobenzonitrile is (1.0-3.0):1, preferably (1.5-2.5):1.

[0019] In some embodiments, the solvent is selected from one or more of toluene, dichloromethane and methyl tert-butyl ether, preferably dichloromethane.

[0020] In some embodiments, the amount of solvent used is 50-150 mL of solvent per equivalent of 2-aminobenzonitrile.

[0021] In some embodiments, the molar ratio of the compound of formula (II) to 2-aminobenzonitrile is (1.0-2.0):1.

[0022] In some embodiments, the reaction temperature is 0-40°C, preferably 30-40°C.

[0023] In some embodiments, the reaction time is 2-24 hours, preferably 2-3 hours.

[0024] In some embodiments, the reaction is carried out under an inert atmosphere.

[0025] In some embodiments, the method further comprises the step of: purifying the prepared N-(2-cyanophenyl)-1,1,1-trifluoromethanesulfonamide by crystallization.

[0026] In some embodiments, one or more solvents selected from n-hexane, n-heptane and petroleum ether are used for crystallization purification, and preferably one or both of petroleum ether and n-heptane are used for crystallization purification.

[0027] In some embodiments, the present invention provides a method for preparing N-(2-cyanophenyl)-1,1,1-trifluoromethanesulfonamide represented by formula (I),

[0028]

[0029] The method comprises the following steps in sequence:

[0030] (1) Under the protection of inert gas, 2-aminobenzonitrile, dichloromethane and 4-lutidine are added to a reaction vessel, stirred evenly, and then heated to 5-35° C., and then trifluoromethanesulfonyl chloride is added. During the process of adding trifluoromethanesulfonyl chloride, the system temperature is controlled not to be higher than 40° C.;

[0031] (2) After adding trifluoromethanesulfonyl chloride, maintain the temperature in the range of 0-40° C. and stir until the reaction is complete;

[0032] (3) lowering the system temperature to 20-25°C, adding hydrochloric acid, and adjusting the system pH to 2-3; after the system is separated into layers, taking the organic layer;

[0033] (4) concentrating the organic layer;

[0034] (5) adding one or more solvents selected from n-hexane, n-heptane and petroleum ether to the organic layer for crystallization, and then filtering to obtain the compound of formula I.

[0035] In some embodiments, the molar ratio of 4-lutidine to 2-aminobenzonitrile is (1.0-3.0):1, preferably (1.5-2.5):1; the molar ratio of trifluoromethanesulfonyl chloride to 2-aminobenzonitrile is (1.0-2.0):1. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is the NMR spectrum of N-(2-cyanophenyl)-1,1,1-trifluoromethanesulfonamide obtained in Example 1. DETAILED DESCRIPTION

[0037] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0038] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0039] Herein, “comprising”, “including”, “containing” and similar terms encompass the meanings of “consisting essentially of” and “consisting of”. For example, when “A comprises B and C” is disclosed herein, “A consists essentially of B and C” and “A consists of B and C” should be deemed to be disclosed herein.

[0040] In this article, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are only for brevity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0041] In this document, unless otherwise specified, percentage refers to mass percentage and ratio refers to mass ratio.

[0042] Herein, when describing embodiments or examples, it should be understood that they are not used to limit the present invention to these embodiments or examples. On the contrary, all substitutes, improvements and equivalents of the methods and materials described in the present invention can be included in the scope limited by the claims.

[0043] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0044] The present invention provides a method for preparing N-(2-cyanophenyl)-1,1,1-trifluoromethanesulfonamide, which comprises the steps of reacting 2-aminobenzonitrile with a compound of formula (II) in a solvent under the action of a base, thereby preparing N-(2-cyanophenyl)-1,1,1-trifluoromethanesulfonamide:

[0045]

[0046] In formula II, R is selected from F, Cl and Br.

[0047] In some embodiments, in the compound of formula (II), R is selected from Cl and Br; preferably, R is Cl. In some embodiments, the compound of formula (II) is trifluoromethanesulfonyl chloride.

[0048] The molar ratio of the compound of formula (II) to 2-aminobenzonitrile can be (1.0-2.0):1, such as 1.0:1, 1.2:1, 1.4:1, 1.6:1, 1.8:1 or within the range of any two of the above molar ratios. The preferred ratio is (1.0-1.5):1 or (1.0-1.2):1.

[0049] A base is added to neutralize the acid generated during the reaction of 2-aminobenzonitrile and the compound of formula (II). The base can be selected from one or more of 4-dimethylaminopyridine, triethylamine and diisopropylethylamine (CAS: 7087-68-5). In some embodiments, the base is 4-dimethylaminopyridine. During the reaction, part of the base is converted into the corresponding salt, and the excess base is converted into the salt during the acidification process after the reaction is completed, and finally enters the water layer to be separated from the product compound of formula (I).

[0050] The molar ratio of the base to the 2-aminobenzonitrile can be (1.0-3.0):1, such as 1.4:1, 1.6:1, 2.0:1, 2.2:1, 2.5:1, 2.8:1 or within the range of any two of the above molar ratios. In some embodiments, the molar ratio of the base to the 2-aminobenzonitrile is (1.5-2.5):1, (1.8-2.2):1 or (2-2.5):1.

[0051] The solvent may be a commonly used solvent in the art, as long as it has no adverse effect on the reaction of 2-aminobenzonitrile with the compound of formula (II). The solvent may be selected from one or more of toluene, dichloromethane and methyl tert-butyl ether. In some embodiments, the solvent is dichloromethane. In some embodiments, the solvent is methyl tert-butyl ether. In some embodiments, the solvent is a mixed solvent of dichloromethane and toluene; preferably, in the mixed solvent, the volume ratio of dichloromethane to toluene is (1-3): (3-1), for example, 1: 1. In some embodiments, the solvent is a mixed solvent of dichloromethane and methyl tert-butyl ether; preferably, in the mixed solvent, the volume ratio of dichloromethane to methyl tert-butyl ether is (1-3): (3-1), for example, 1: 1.

[0052] The amount of the solvent can be a conventional amount that meets the reaction requirements. An exemplary amount is 100-200 mL of solvent per equivalent of 2-aminobenzonitrile.

[0053] The reaction temperature may be 0-40°C, for example 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 32°C, 35°C, 38°C, 40°C or within the range of any two of the above temperatures. The preferred reaction temperature is 30-40°C or 35-40°C.

[0054] There is no particular restriction on the reaction time, as long as the reaction is completed. Usually, depending on the type of reactants, the amount of reactants and the situation of the solvent, the reaction time can be 2-24 hours, for example, 3 hours, 4 hours, 5 hours, 8 hours, 10 hours, 15 hours, 20 hours or within the range of any two of the above times. Preferably, it is 2-3 hours.

[0055] The reaction is usually carried out under the protection of an inert gas such as nitrogen.

[0056] In some embodiments, 2-aminobenzonitrile, a base and a solvent are first added to a reaction container, stirred evenly and then heated to 30±3°C, and then the compound of formula (II) is added, and the system temperature is controlled not to be higher than 40°C. After the addition is completed, the temperature is maintained at 35-40°C and stirred until the reaction is completed, thereby preparing N-(2-cyanophenyl)-1,1,1-trifluoromethanesulfonamide.

[0057] In some embodiments, after the reaction of 2-aminobenzonitrile with the compound of formula (II) is completed, the reaction solution is acidified to convert all the added base into the corresponding salt. There is no particular restriction on the type, concentration and dosage of the acid, as long as the pH value of the reaction system can be controlled to 2-3. For example, hydrochloric acid can be used. The concentration of hydrochloric acid can be 1.5-2.5N, such as 2N. After the acidification is completed, the pH of the reaction solution is 2-3. After acidification, the aqueous phase and the organic phase in the reaction solution are separated, and the product N-(2-cyanophenyl)-1,1,1-trifluoromethanesulfonamide is in the organic phase and the salt is in the aqueous phase. The organic phase containing the product N-(2-cyanophenyl)-1,1,1-trifluoromethanesulfonamide is concentrated to obtain a concentrated solution.

[0058] It should be understood that before the acidification treatment, if the temperature of the reaction system is high, the temperature of the reaction system can be first lowered to room temperature, such as about 20±5° C., and then the acidification treatment can be performed.

[0059] In some embodiments, the method of the present invention further comprises the step of: crystallizing and purifying the obtained N-(2-cyanophenyl)-1,1,1-trifluoromethanesulfonamide. Crystallization and purification can be performed using one or more solvents selected from n-hexane, n-heptane and petroleum ether, preferably using petroleum ether and / or n-heptane. In some embodiments, crystallization and purification are performed using n-heptane. In some embodiments, crystallization and purification are performed using a mixed solvent of n-heptane and petroleum ether; preferably, in the mixed solvent, the volume ratio of n-heptane to petroleum ether is (1-3):(3-1), for example, 1:1.

[0060] In some embodiments, in dichloromethane, trifluoromethanesulfonyl chloride and 2-aminobenzonitrile react under the action of 4-dimethylaminopyridine to obtain N-(2-cyanophenyl)-1,1,1-trifluoromethanesulfonamide. In some embodiments, the molar ratio of the amount of 4-dimethylaminopyridine to 2-aminobenzonitrile is (2.0-2.5):1. In some embodiments, the molar ratio of the amount of trifluoromethanesulfonyl chloride to 2-aminobenzonitrile is: (1.0-2.0):1. In some embodiments, the reaction is carried out at 30-40°C for 2-3 hours. In some embodiments, after the reaction is completed, the obtained N-(2-cyanophenyl)-1,1,1-trifluoromethanesulfonamide is crystallized and purified using n-heptane or a mixed solvent of petroleum ether and n-heptane for crystallization purification.

[0061] In some embodiments, the present invention provides a method for preparing N-(2-cyanophenyl)-1,1,1-trifluoromethanesulfonamide represented by formula (I),

[0062]

[0063] The method comprises the following steps in sequence:

[0064] (1) Under the protection of inert gas, 2-aminobenzonitrile, dichloromethane and 4-lutidine are added to a reaction vessel, stirred evenly, and then heated to 5-35° C., and then trifluoromethanesulfonyl chloride is added. During the process of adding trifluoromethanesulfonyl chloride, the system temperature is controlled not to be higher than 40° C.;

[0065] (2) After adding trifluoromethanesulfonyl chloride, maintain the temperature in the range of 0-40° C. and stir until the reaction is complete;

[0066] (3) lowering the system temperature to 20-25°C, adding hydrochloric acid, and adjusting the system pH to 2-3; after the system is separated into layers, taking the organic layer;

[0067] (4) concentrating the organic layer; and

[0068] (5) adding one or more solvents selected from n-hexane, n-heptane and petroleum ether to the organic layer for crystallization, and then filtering to obtain the compound of formula I.

[0069] In some embodiments, the molar ratio of 4-lutidine to 2-aminobenzonitrile is (1.0-3.0):1, preferably (1.5-2.5):1.

[0070] In some embodiments, the molar ratio of trifluoromethanesulfonyl chloride to 2-aminobenzonitrile is (1.0-2.0):1.

[0071] In some embodiments, in step (1), under the protection of inert gas, 2-aminobenzonitrile, dichloromethane and 4-lutidine are added to a reaction vessel, stirred evenly and then heated to 15-35°C, and then trifluoromethanesulfonyl chloride is added. Preferably, stirred evenly and then heated to 30-35°C, and then trifluoromethanesulfonyl chloride is added.

[0072] In some embodiments, in step (2), after adding trifluoromethanesulfonyl chloride, the temperature is maintained in the range of 30-40° C. and stirred until the reaction is complete. Preferably, the temperature is maintained in the range of 35-40° C. and stirred until the reaction is complete.

[0073] The yield of N-(2-cyanophenyl)-1,1,1-trifluoromethanesulfonamide prepared by the method of the present invention is 50% or more, 60% or more, 70% or more, 75% or more, 76% or more, 80% or more, 85% or more, 87% or more, 88% or more, 90% or more, 95% or more or 98% or more.

[0074] The purity of N-(2-cyanophenyl)-1,1,1-trifluoromethanesulfonamide prepared by the method of the invention is above 97%, above 98%, above 99% or above 99.4%.

[0075] The present invention also provides the use of 2-aminobenzonitrile in the method for preparing N-(2-cyanophenyl)-1,1,1-trifluoromethanesulfonamide shown in formula (I). In some embodiments, 2-aminobenzonitrile reacts with a compound of formula (II) to prepare N-(2-cyanophenyl)-1,1,1-trifluoromethanesulfonamide shown in formula (I). In some embodiments, the method for reacting 2-aminobenzonitrile with a compound of formula (II) and the compound of formula (II) are as described in any embodiment of the present invention.

[0076] The present invention also provides the use of the compound of formula (II) in the method for preparing N-(2-cyanophenyl)-1,1,1-trifluoromethanesulfonamide shown in formula (I). In some embodiments, the compound of formula (II) reacts with 2-aminobenzonitrile to prepare N-(2-cyanophenyl)-1,1,1-trifluoromethanesulfonamide shown in formula (I). In some embodiments, the method for reacting 2-aminobenzonitrile with the compound of formula (II) and the compound of formula (II) are as described in any embodiment of the present invention.

[0077] The present invention has the following beneficial effects:

[0078] In the method of the present invention, a low-priced compound of formula (II) (such as trifluoromethanesulfonyl chloride, CAS No.: 421-83-0) is used to replace expensive trifluoromethanesulfonic anhydride (CAS No.: 358-23-6). The method of the present invention has a complete and clean reaction and is easy to post-process. The prepared N-(2-cyanophenyl)-1,1,1-trifluoromethanesulfonamide has a high yield and high purity, and the byproduct is only sodium chloride.

[0079] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods in the following examples without specifying specific conditions are usually based on conventional conditions or the conditions recommended by the manufacturer. Unless otherwise stated, percentages and parts are calculated by weight.

[0080] Herein, the solvent may be a mixture of two solvents, and the numerical ratio of the two solvents constituting the mixed solvent is the specific volume of the two solvents.

[0081] Herein, the amounts of the base and the compound of formula (II) expressed in equivalents are calculated based on 2-aminobenzonitrile.

[0082] HPLC analysis conditions are as follows:

[0083] Column model: Waters XBridge TM C8 150mm x 4.6mm 3.5μm;

[0084] P / N:186003055;

[0085] Flow rate: 1.0 ml / min;

[0086] Washing conditions: gradient washing;

[0087] Running time: 25 minutes

[0088] Equilibration time: 5 minutes;

[0089] Detector: UV 254 nm;

[0090] Injection: 10 μl;

[0091] Column temperature: 35°C;

[0092] Autosampler temperature: room temperature;

[0093] Mobile phase ratio:

[0094] A: water / trifluoroacetic acid = 100:0.1 (volume ratio);

[0095] B: acetonitrile / trifluoroacetic acid = 100:0.1 (volume ratio);

[0096] Sample dissolving solvent: acetonitrile / water = 1:1;

[0097] The gradient is shown in Table 1 below:

[0098] Table 1

[0099]

[0100]

[0101] Equipment and reagents are as follows:

[0102] Scale: Mettler Toledo MT 5;

[0103] Acetonitrile: Merck LiChrosolv, HPLC grade;

[0104] Water: Merck LiChrosolv, HPLC grade;

[0105] Trifluoroacetic acid: Alfar, HPLC grade.

[0106] Example 1

[0107] A 500 ml four-necked flask was mechanically stirred, and a thermometer, condenser and constant pressure funnel were added. Under nitrogen protection, the starting material 2-aminobenzonitrile (CAS No: 1885-29-6) (15.0 g, 127.0 mmol, 1.0 equivalent), 4-dimethylaminopyridine (DMAP, 31.03 g, 254.0 mmol, 2.0 equivalent) and 150 ml of dichloromethane were added to the reaction flask, stirred and heated to 30°C. Trifluoromethanesulfonyl chloride (CAS No: 421-83-0) (21.4 g, 127.0 mmol, 1.0 equivalent) was added dropwise, and the addition process was accompanied by heat release, and the internal temperature was controlled below 40°C. After the addition was completed, the mixture was kept at 35-40°C and stirred for 2 hours, and the reaction was monitored by HPLC to be complete. The temperature was lowered to 20°C, and the pH was adjusted to 2-3 with 2N hydrochloric acid. After separation, 4-dimethylaminopyridine hydrochloride would enter the water layer (for recycling), and the product would be in the organic layer. The organic layer was dried with anhydrous sodium sulfate and concentrated to about 30 ml, and n-heptane was added for crystallization, filtered, and dried to obtain the final product with a yield of 90.0% and a HPLC purity of 99.0%.

[0108] 1 H-NMR (CDCl 3 ,ppm)δ7.20~7.24(m,1H),7.44~7.46(m,1H),7.55~7.57(m,1H),7.69~7.71(m,1H),10.1(br,1H).

[0109] Embodiment 2-5

[0110] The method of Example 1 was repeated, the only difference being that a different reaction solvent was used. The preparation method and yield are shown in Table 2.

[0111] Table 2

[0112]

[0113] Embodiment 6-9

[0114] The method of Example 1 was repeated, with the only difference being the molar ratio of 4-dimethylaminopyridine to 2-aminobenzonitrile. The preparation method and yield are shown in Table 3.

[0115] Table 3

[0116]

[0117]

[0118] Examples 10-12

[0119] The method of Example 1 was repeated, except that different bases and reaction solvents were used. The preparation method and yield are shown in Table 4.

[0120] Table 4

[0121]

[0122] Examples 13-15

[0123] The method of Example 1 was repeated, with the only difference being the molar ratio of trifluoromethanesulfonyl chloride to 2-aminobenzonitrile. The preparation method and yield are shown in Table 5.

[0124] Table 5

[0125]

[0126]

[0127] Examples 16-19

[0128] The method of Example 1 was repeated, except for the reaction temperature and reaction time. The preparation method and yield are shown in Table 6.

[0129] Table 6

[0130]

[0131] In the temperature control column, 1) is the temperature of the reaction system before the trifluoroacetyl chloride is added dropwise; 2) is the temperature of the reaction system during the process of adding trifluoroacetyl chloride; 3) is the temperature of the reaction system after the trifluoromethanesulfonyl chloride is added to the reaction system.

[0132] Embodiment 20

[0133] A 500 ml four-necked flask was mechanically stirred, and a thermometer, condenser and constant pressure funnel were added. Under nitrogen protection, the starting material 2-aminobenzonitrile (CAS No: 1885-29-6) (15.0 g, 127.0 mmol, 1.0 equivalent), 4-dimethylaminopyridine (DMAP, 31.03 g, 254.0 mmol, 2.0 equivalent) and 150 ml of dichloromethane were added to the reaction flask, stirred and heated to 30°C. Trifluoromethanesulfonyl bromide (CAS No: 15458-53-4) (27.04 g, 127.0 mmol, 1.0 equivalent) was added dropwise, and the addition process was accompanied by heat release, and the internal temperature was controlled below 40°C. After the addition was completed, the mixture was kept at 35-40°C and stirred for 2 hours, and the reaction was monitored by HPLC to be complete. The temperature was lowered to 20°C, and the pH was adjusted to 2-3 with 2N hydrochloric acid. After separation, 4-dimethylaminopyridine hydrochloride would enter the water layer (for recycling), and the product would be in the organic layer. The organic layer was dried with anhydrous sodium sulfate and concentrated to about 30 ml, and n-heptane was added for crystallization, filtered, and dried to obtain the final product with a yield of 82.1% and a HPLC purity of 98.7%.

[0134] Embodiment 21

[0135] A 500 ml four-necked flask was mechanically stirred, and a thermometer, condenser and constant pressure funnel were added. Under nitrogen protection, the starting material 2-aminobenzonitrile (CAS No: 1885-29-6) (15.0 g, 127.0 mmol, 1.0 equivalent), 4-dimethylaminopyridine (DMAP, 31.03 g, 254.0 mmol, 2.0 equivalent) and 150 ml of dichloromethane were added to the reaction flask, stirred and heated to 30°C. Trifluoromethanesulfonyl fluoride (CAS No: 335-05-7) (19.31 g, 127.0 mmol, 1.0 equivalent) was added dropwise, and the addition process was accompanied by heat release, and the internal temperature was controlled below 40°C. After the addition was completed, the mixture was kept at 35-40°C and stirred for 2 hours, and the reaction was monitored by HPLC to be complete. The temperature was lowered to 20°C, and the pH was adjusted to 2-3 with 2N hydrochloric acid. After separation, 4-dimethylaminopyridine hydrochloride would enter the water layer (for recycling), and the product would be in the organic layer. The organic layer was dried with anhydrous sodium sulfate and concentrated to about 30 ml, and n-heptane was added for crystallization, filtered, and dried to obtain the final product with a yield of 70.3% and a HPLC purity of 99.2%.

[0136] Examples 22-24

[0137] The method of Example 1 was repeated, with the only difference being that a different crystallization solvent was used. The preparation method and yield are shown in Table 7.

[0138] Table 7

[0139]

[0140]

Claims

1. A method for preparing N-(2-cyanophenyl)-1,1,1-trifluoromethanesulfonamide represented by formula (I), characterized in that: The method comprises the steps of reacting 2-aminobenzonitrile with a compound of formula (II) in a solvent under the action of a base: In formula (II), R is selected from F, Cl and Br.

2. The method according to claim 1, characterized in that In formula (II), R is selected from Cl and Br; preferably, R is Cl.

3. The method according to claim 1, characterized in that: The base is selected from one or more of 4-dimethylaminopyridine, triethylamine and diisopropylethylamine; preferably, the base is 4-dimethylaminopyridine; and / or The molar ratio of the base to 2-aminobenzonitrile is (1.0-3.0):1, preferably (1.5-2.5):

1.

4. The method according to claim 1, characterized in that: The solvent is selected from one or more of toluene, dichloromethane and methyl tert-butyl ether, preferably dichloromethane; and / or The amount of the solvent used is 50-150 mL of solvent per equivalent of 2-aminobenzonitrile.

5. The method according to claim 1, characterized in that The molar ratio of the compound of formula (II) to 2-aminobenzonitrile is (1.0-2.0):

1.

6. The method according to claim 1, characterized in that: The reaction temperature is 0-40°C, preferably 30-40°C; and / or The reaction time is 2-24 hours, preferably 2-3 hours; and / or The reaction was carried out under inert atmosphere.

7. The method according to claim 1, characterized in that The method further comprises the step of: crystallizing and purifying the prepared N-(2-cyanophenyl)-1,1,1-trifluoromethanesulfonamide.

8. The method according to claim 7, characterized in that One or more solvents selected from n-hexane, n-heptane and petroleum ether are used for crystallization purification, and one or two of petroleum ether and n-heptane are preferably used for crystallization purification.

9. A method for preparing N-(2-cyanophenyl)-1,1,1-trifluoromethanesulfonamide represented by formula (I), It is characterized in that The method comprises the following steps in sequence: (1) Under the protection of inert gas, 2-aminobenzonitrile, dichloromethane and 4-lutidine are added to a reaction vessel, stirred evenly, and then heated to 5-35° C., and then trifluoromethanesulfonyl chloride is added. During the process of adding trifluoromethanesulfonyl chloride, the system temperature is controlled not to be higher than 40° C.; (2) After adding trifluoromethanesulfonyl chloride, maintain the temperature in the range of 0-40° C. and stir until the reaction is complete; (3) lowering the system temperature to 20-25°C, adding hydrochloric acid, and adjusting the system pH to 2-3; after the system is separated into layers, taking the organic layer; (4) concentrating the organic layer; and (5) adding one or more solvents selected from n-hexane, n-heptane and petroleum ether to the organic layer for crystallization, and then filtering to obtain the compound of formula I.

10. The method according to claim 9, characterized in that: The molar ratio of 4-lutidine to 2-aminobenzonitrile is (1.0-3.0):1, preferably (1.5-2.5):1; The molar ratio of trifluoromethanesulfonyl chloride to 2-aminobenzonitrile is (1.0-2.0):1.

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