CN110615764A - N- (2-benzamide) -1H-pyrazole-4-formamide compound and preparation method and application thereof - Google Patents

Abstract

The invention discloses an N-(2-benzamide) -1H -pyrazole-4-carboxamide compound, a preparation method and application thereof. N-(2-benzamide)-1 H -pyrazole-4-carboxamide compounds, namely N-(2-benzamide)-3-(difluoromethyl)-1-methyl-1 H Pyrazole-4-carboxamide compounds, its structural formula is shown in formula (I): In formula (I): R is phenyl or substituted phenyl, the number of substituents on the benzene ring of the substituted phenyl is one or more, and each substituent is independently selected from halogen, C1-C3 alkyl or C1-C3alkoxy. The N-(2-benzamide)-3-(difluoromethyl)-1-methyl-1 H -pyrazole-4-carboxamide compounds disclosed in the present invention are novel compounds with bactericidal activity, which are in 50ppm concentration of rice sheath blight has a good inhibition rate, which provides a basis for the research and development of new pesticides.

Description

A kind of N-(2-benzamide)-1H-pyrazole-4-carboxamide compound and preparation thereof methods and applications

technical field

The present invention relates to an N-(2-benzamide)-1H-pyrazole-4-carboxamide compound and a preparation method and application thereof.

Background technique

Nowadays, pyrazole amide compounds usually have excellent and extensive biological activities such as low toxicity and high efficiency due to their highly active structural groups such as pyrazole and amide. As an important member of nitrogen-containing heterocycles, pyrazole rings are Its structure is very unique, and it has high biological activity against a variety of microorganisms, pathogenic factors and diseases, so it is not only used in the field of sterilization, insecticidal and acaricidal, but also widely used in the field of weeding, and even in medicine It also has applications in the field of anticancer. In recent years, some foreign multinational pesticide giants are also very interested in the development of bisamide insecticides. The ones that have been listed include chlorantraniliprole and cyantraniliprole developed by DuPont, and fluorine fluoride jointly developed by Bayer and Japan Pesticide Co., Ltd. benzilamide. There are Tetraniliprol of Bayer, bromiliprole developed by BASF and Mitsui Chemicals, etc. under development. Such compounds have the advantages of low residues to plants, little phytotoxicity, and low acute toxicity to mammals.

The design and synthesis of new pyrazole bisacyl fungicides is of great significance for us to develop new pesticides with high efficiency, low toxicity and low residues.

SUMMARY OF THE INVENTION

In view of the above-mentioned technical problems existing in the prior art, the object of the present invention is to provide a kind of N-(2-benzamide)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-methyl Amide compound and its preparation method and application. The present invention is based on the structure of SDH inhibitors such as fluconazole, takes the pyrazole amide structure as the parent, introduces extension and substituted benzamide, etc., and introduces a difluoromethyl group at the 3-position of the pyrazole ring to investigate the compound The influence of biological activity, designed and synthesized a series of compounds such as pyrazole bisacyl.

Described a kind of N-(2-benzamide)-1H-pyrazole-4-carboxamide compound, namely N-(2-benzamide)-3-(difluoromethyl)-1-formaldehyde Base-1H-pyrazole-4-carboxamide compound, characterized in that its structural formula is shown in formula (I):

In formula (I): R is phenyl or substituted phenyl, the number of substituents on the benzene ring of the substituted phenyl is one or more, and each substituent is independently selected from halogen, C1-C3 alkyl or C1-C3 alkoxy.

Described a kind of N-(2-benzamide)-1H-pyrazole-4-carboxamide compound, it is characterized in that in formula (I), R is one of the following: 2-methylphenyl, 2, 6-dichlorophenyl, 2,3-dichlorophenyl, 4-methoxyphenyl, 2,4-dichlorophenyl, phenyl.

Described a kind of preparation method of N-(2-benzamide)-1H-pyrazole-4-carboxamide compound, it is characterized in that comprising the following steps:

1) Ethyl difluoroacetoacetate and triethyl orthoformate are warmed to reflux reaction in organic solvent A, after the reaction is finished, the solvent is concentrated and removed, and the concentrated residue is added to the mixed solution of methyl hydrazine aqueous solution and organic solvent B, in The reaction was stirred at a temperature of 45-60 °C, and the reaction progress was tracked by TLC; after the reaction was completed, the reaction solution was post-treated to obtain 1-methyl-3-difluoromethyl-1H-pyrazole-4 shown in formula (II). - ethyl formate;

2) 1-methyl-3-difluoromethyl-1H-pyrazole-4-carboxylic acid ethyl ester shown in the formula (II) obtained in step 1) was added to the NaOH aqueous solution with a mass concentration of 8 to 12%, and then Stir the reaction at a temperature of 55-70°C until the reaction liquid system is transparent, and after naturally cooling to room temperature, add acid to adjust the pH of the reaction liquid to 1.5-3.0, precipitate solids, filter with suction, and dry the filter residue to obtain the formula (III). 1-methyl-3-difluoromethyl-1H-pyrazole-4-carboxylic acid;

3) Step 2) The obtained 1-methyl-3-difluoromethyl-1H-pyrazole-4-carboxylic acid represented by the formula (III) is heated to reflux reaction in thionyl chloride, and after the reaction is finished, it is concentrated to remove excess thionyl chloride, the concentrated residue was reacted with N-Boc-ethylenediamine and triethylamine in organic solvent C at room temperature, and the reaction progress was followed by TLC. After the reaction was completed, the solvent was distilled and concentrated to remove the solvent. Column chromatography to obtain (2-(3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamido)ethyl)carbamic acid tert-butyl shown in formula (IV) ester;

4) tertiary (2-(3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamido)ethyl)carbamic acid shown in formula (IV) obtained in step 3) Butyl ester and trifluoromethyl acetic acid are warmed to reflux reaction in organic solvent D, TLC tracks the reaction progress, after the reaction is finished, the solvent is distilled and concentrated to remove the solvent, and the distillation concentrate is separated by column chromatography to obtain N as shown in formula (V). -(2-Aminoethyl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide;

5) N-(2-aminoethyl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide represented by formula (V) obtained in step 4), organic After the solvent E and triethylamine are stirred and mixed uniformly, substituted benzoyl chloride is added dropwise, and the reaction is stirred at room temperature. TLC tracks the reaction progress. After the reaction is completed, the solvent is evaporated and concentrated to remove the solvent. The concentrated residue is separated and purified by column chromatography. To obtain N-(2-benzamide)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide compounds represented by formula (I);

Wherein, the number of substituents on the benzene ring of the substituted benzoyl chloride is one or more, and each substituent is independently selected from H, halogen, C1-C3 alkyl or C1-C3 alkoxy.

The method for preparing a N-(2-benzamide)-1H-pyrazole-4-carboxamide compound is characterized in that the organic solvent A in step 1) is acetic anhydride, and the organic solvent B is ethanol ; The organic solvent C in step 3), the organic solvent D in step 4) and the organic solvent E in step 5) are all methylene chloride.

Described a kind of preparation method of N-(2-benzamide)-1H-pyrazole-4-carboxamide compound, it is characterized in that in step 1), described ethyl difluoroacetoacetate, orthoformic acid triacetate The molar ratio of ethyl ester and methyl hydrazine is 1:1.1-1.5:1.1-1.5.

The method for preparing a N-(2-benzamide)-1H-pyrazole-4-carboxamide compound is characterized in that in step 3), the 1-methyl- The molar ratio of 3-difluoromethyl-1H-pyrazole-4-carboxylic acid to N-Boc-ethylenediamine is 1:1.1 to 1.5; in step 4), (2-( The molar ratio of 3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamido)ethyl)carbamate and trifluoromethylacetic acid is 1:1.05-1.2.

Described a kind of preparation method of N-(2-benzamide)-1H-pyrazole-4-carboxamide compound, it is characterized in that in step 5), N-(2- The molar ratio of aminoethyl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide to substituted benzoyl chloride is 1:1.05-1.2.

Described a kind of preparation method of N-(2-benzamide)-1H-pyrazole-4-carboxamide compound, it is characterized in that in step 1) in the mol ratio of organic solvent A and ethyl difluoroacetoacetate is 2 to 4:1, and the volumetric dosage of organic solvent B is 0.3 to 0.8 ml/mmol based on the amount of ethyl difluoroacetoacetate; the volumetric dosage of organic solvent C in step 3) is shown in formula (III) The amount of the substance of the 1-methyl-3-difluoromethyl-1H-pyrazole-4-carboxylic acid is calculated as 0.5～1.0ml/mmol; In step 4), the volume dosage of the organic reagent D is represented by formula (IV) The amount of (2-(3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamido)ethyl)carbamic acid tert-butyl ester shown is 5 to 8 ml/mmol ; The volume consumption of organic reagent E in step 5) is N-(2-aminoethyl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4- The amount of the formamide substance was 5 to 8 ml/mmol.

Described a kind of preparation method of N-(2-benzamide)-1H-pyrazole-4-carboxamide compound, it is characterized in that step 3), step 4) and step 5) in column chromatography separation The eluent is a mixture of ethyl acetate and petroleum ether with a volume ratio of 1:0.5-2.

The application of the N-(2-benzamide)-1H-pyrazole-4-carboxamide compound in the preparation of fungicides.

The synthetic process route of N-(2-benzamide)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide compounds of the present invention is as follows:

Compared with the prior art, the beneficial effects of the present invention are mainly reflected in: the present invention provides a N-(2-benzamide)-3-(difluoromethyl)-1-methyl-1H-pyrazole -4-Carboxamide compound and its preparation method and its application in the preparation of fungicides, the preparation method is simple, the operation is convenient, the obtained compound has the best inhibitory activity against Rhizoctonia solani at a concentration of 50 ppm, and the inhibition rate reaches 54.3 %, the compound of the present invention is a new compound with bactericidal activity, which provides a basis for the research and development of new pesticides.

Detailed ways

The present invention will be further described below with reference to specific embodiments, but the protection scope of the present invention is not limited thereto.

Example 1 Preparation of 3-(difluoromethyl)-1-methyl-N-(2-(2-methylbenzamido)ethyl)-1H-pyrazole-4-carboxamide

1) Synthesis of 1-methyl-3-trifluoromethyl-1H-pyrazole-4-carboxylic acid ethyl ester (II):

After refluxing ethyl difluoroacetoacetate (50.0 mmol) and triethyl orthoformate (60 mmol) in acetic anhydride (150.0 mmol) for 8 hours (detecting the complete conversion of the reactants), the reaction solution was concentrated under reduced pressure to remove excess Triethyl orthoformate and acetic anhydride solvent, the concentrated residue was added to a mixed solution of 8.3 g of 40% methyl hydrazine aqueous solution and 25 mL of ethanol under ice bath conditions, and then the temperature was raised to 50 ° C for reaction, TLC tracking Reaction process, after the reaction is finished, distillation is concentrated to remove the solvent, and 20 mL of ethyl acetate and 20 mL of saturated brine are added to the distillation concentrate for extraction and layering, and the organic layer is washed twice with saturated brine (saturated brine used for each washing). volume 20mL), then dried over anhydrous magnesium sulfate, rotary evaporation to remove residual solvent, to obtain 1-methyl-3-difluoromethyl-1H-pyrazole-4-carboxylic acid ethyl ester represented by formula (II) ;

2) Synthesis of 1-methyl-3-difluoromethyl-1H-pyrazole-4-carboxylic acid (III):

In a 100mL reaction flask, add 1-methyl-3-difluoromethyl-1H-pyrazole-4-carboxylic acid ethyl ester (38mmol) represented by formula (II), and then add 10% mass concentration of 30 mL of NaOH aqueous solution was heated to 60 °C and stirred until the reaction solution was transparent, then cooled to room temperature naturally, acid was added to the reaction solution to adjust the pH to about 2.0, a solid was precipitated, suction filtered, and the filter residue was washed with water and dried to obtain formula (III) 1-Methyl-3-difluoromethyl-1H-pyrazole-4-carboxylic acid shown.

3) Synthesis of (2-(3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamido)ethyl) tert-butyl carbamate (IV):

1-Methyl-3-difluoromethyl-1H-pyrazole-4-carboxylic acid (30 mmol) represented by formula (III) was mixed with 10 mL of thionyl chloride and heated to reflux for reaction, and the reaction solution changed from turbidity to After it became clear and transparent, the reaction was continued for 30 min, the reaction stopped, and after cooling to room temperature, the excess thionyl chloride was removed by concentration, and the concentrated residue was diluted and mixed with 10 mL of dichloromethane to prepare solution A for later use.

The above-prepared solution A was added dropwise to a mixture of 15 mL of dichloromethane, N-Boc-ethylenediamine (40.0 mmol) and 4 mL of triethylamine, and the reaction was stirred at room temperature, and the TLC tracked the reaction process; the reaction ended After concentrating to remove the solvent, the concentrated residue is separated and purified by column chromatography (eluent is petroleum ether and ethyl acetate in a volume ratio of 1:1) to obtain (2-(3-(difluoromethyl) as shown in formula (IV). yl)-1-methyl-1H-pyrazole-4-carboxamido)ethyl)carbamic acid tert-butyl ester;

4) Synthesis of N-(2-aminoethyl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide (V):

(2-(3-(difluoromethyl)-1-methyl-1H-pyrazol-4-carboxamido)ethyl) tert-butyl carbamate (1.5mmol) represented by formula (IV) 10 mL of dichloromethane was added, and after stirring evenly, trifluoromethyl acetic acid (1.6 mmol) was added, the temperature was raised and refluxed for 2 h, and the reaction progress was followed by TLC; after the reaction was completed, the solvent was concentrated and removed, and the concentrated residue was separated and purified by column chromatography (eluting The agent is petroleum ether and ethyl acetate in a volume ratio of 1:1) to obtain N-(2-aminoethyl)-3-(difluoromethyl)-1-methyl-1H-pyrazole represented by formula (V) -4-Carboxamide.

5) Synthesis of 3-(difluoromethyl)-1-methyl-N-(2-(2-methylbenzamido)ethyl)-1H-pyrazole-4-carboxamide (G1):

N-(2-aminoethyl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide (1.5 mmol) represented by formula (V) was added with 10 mL of dichloromethane Methane and 1 mL of triethylamine were stirred evenly, then 2-methylbenzoyl chloride (1.6 mmol) was added dropwise, the reaction was stirred at room temperature, and the reaction progress was followed by TLC; after the reaction was completed, the solvent was concentrated and removed, and the concentrated residue was separated and purified by column chromatography (The eluent is petroleum ether and ethyl acetate in a volume ratio of 1:1) to obtain 3-(difluoromethyl)-1-methyl-N-(2-(2-methyl) represented by formula (G1) Benzoamido)ethyl)-1H-pyrazole-4-carboxamide.

3-(Difluoromethyl)-1-methyl-N-(2-(2-methylbenzamido)ethyl)-1H-pyrazole-4-carboxamide: white solid, yield: 68.3 %, melting point: 113-116°C; ¹ HNMR (CDCl ₃ , 500MHz), δ: 7.85 (s, 1H, py), 7.37-7.29 (m, 1H, ph), 7.28 (s, 1H, ph), 7.23 -7.17(m, 2H, ph), 7.05(t, J=54.0Hz, 1H, CHF ₂ ), 6.65(s, 1H, NH), 3.85(s, 3H, CH ₃ ), 3.66-3.75(m, 4H, _CH2 ), 2.40 (s, 3H, _CH3 ).

Example 2 N-(2-(2,6-dichlorobenzamide)ethyl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide

2-methylbenzoyl chloride in step 5) of Example 1 is replaced with 2,6-dichlorobenzoyl chloride of an equivalent molar amount, and other operations are the same as in Example 1, to obtain the target compound shown in the formula (G2). N-(2-(2,6-Dichlorobenzamide)ethyl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide;

N-(2-(2,6-Dichlorobenzamide)ethyl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide: white solid, yield: 63.5%, melting point: 109-113°C; ¹ H NMR (CDCl ₃ , 500MHz), δ: 7.86 (s, 1H, py), 7.35-7.31 (m, 2H, ph), 7.29 (s, 1H, ph) , 7.12-6.89 (m, 2H, ph, CHF ₂ ), 6.52 (s, 1H, NH), 3.94 (s, 3H, CH ₃ ), 3.75-3.68 (m, 4H, CH ₂ ).

Example 3 Preparation of N-(2-(2,3-dichlorobenzamide)ethyl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide

2-methylbenzoyl chloride in step 5) of Example 1 was replaced with 2,3-dichlorobenzoyl chloride in an equivalent molar amount, and other operations were the same as in Example 1 to obtain N- (2-(2,3-Dichlorobenzamide)ethyl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide;

N-(2-(2,3-Dichlorobenzamide)ethyl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide: white solid, yield: 53.1%, melting point: 105-107°C; ¹ H NMR (CDCl ₃ , 500MHz), δ: 7.88 (s, 1H, py), 7.53-7.58 (m, 1H, ph), 7.39-7.45 (m, 1H, ph), 7.25 (t, J=8.0Hz, 1H, ph), 7.08-6.85 (m, 2H, ph, CHF ₂ ), 6.82 (s, 1H, NH), 3.93 (s, 3H, CH ₃ ), 3.69-3.75 (m, 4H, CH ₂ ).

Example 4 Preparation of 3-(difluoromethyl)-N-(2-(4-methoxybenzamido)ethyl)-1-methyl-1H-pyrazole-4-carboxamide

Replace the 2-methylbenzoyl chloride in step 5 of Example 1 with 4-methoxybenzoyl chloride of an equivalent molar amount, and other operations are the same as in Example 1 to obtain 3-( Difluoromethyl)-N-(2-(4-methoxybenzamido)ethyl)-1-methyl-1H-pyrazole-4-carboxamide;

3-(Difluoromethyl)-N-(2-(4-methoxybenzamido)ethyl)-1-methyl-1H-pyrazole-4-carboxamide: white solid, yield: 47.5%, melting point: 96-98°C; ¹ H NMR (CDCl ₃ , 500MHz), δ: 7.88(d, J=9.0Hz, 2H, py, ph), 7.84(s, 1H, ph), 7.08(s) , 1H, ph), 6.94 (t, J=54.0Hz, 1H, CHF ₂ ), 6.81 (d, J=9.0Hz, 1H, ph), 6.65 (s, 1H, NH), 3.78 (s, 3H, CH ₃ ), 3.75 (s, 3H, CH ₃ O), 3.69-3.74 (m, 4H, CH ₂ ).

Example 5 Preparation of N-(2-(2,4-dichlorobenzamide)ethyl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide

2-methylbenzoyl chloride in step 5) of Example 1 was replaced with 2,4-dichlorobenzoyl chloride in an equivalent molar amount, and other operations were the same as in Example 1 to obtain N- (2-(2,4-Dichlorobenzamide)ethyl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide;

N-(2-(2,4-Dichlorobenzamide)ethyl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide: white solid, yield 46.2 %, melting point: 93-97°C; ¹ H NMR (CDCl ₃ , 500MHz), δ: 7.86 (s, 1H, py), 7.63-7.59 (m, 1H, ph), 7.52 (d, J=8.0Hz, 1H, ph), 7.20 (t, J=8.0Hz, 1H, ph), 7.03-6.80 (m, 2H, ph, CHF ₂ ), 6.61 (s, 1H, NH), 3.82 (s, 3H, CH ₃ ), 3.73-3.78(m, 4H, CH ₂ ).

Example 6 Preparation of N-(2-benzoylaminoethyl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide

The 2-methylbenzoyl chloride in Example 1, step 5) was replaced with the same molar amount of benzoyl chloride, and other operations were the same as in Example 1 to obtain N-(2-benzoyl chloride as shown in formula (G6) aminoethyl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide;

N-(2-Benzamidoethyl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide: white solid, yield: 51.7%, melting point: 103- 106°C; ¹ H NMR (CDCl ₃ , 500MHz), δ: 7.94-8.04 (m, 2H, py, ph), 7.84 (s, 1H, ph), 7.47 (m, 1H, ph), 7.34 (t, J=8.0Hz, 2H, ph), 6.93 (t, J=54.0Hz, 1H, CHF ₂ ), 6.67 (s, 1H, NH), 3.77 (s, 3H, CH ₃ ), 3.71-3.76 (m, 4H, CH ₂ ).

Example 7 Bactericidal activity test

Test objects: Alternaria solani, Gibberellazeae, Phytophthora infestans, Phytophthoracapsici, Sclerotinia sclerotiorum, Botrytis cucumber (Botrytiscinerea), Riziocotinia solani, Cucumber Fusarium oxysporum, Cercospora arachidicola, and Botryosphaeria berengriana.

The compounds represented by formula (G1) to formula (G6) prepared in Examples 1 to 6 were respectively marked as compounds to be tested, and the bactericidal activity test was carried out in the following manner:

Experimental treatment: each compound to be tested was dissolved in DMSO into a 1% EC stock solution for later use. The inhibition zone method was used to evaluate the indoor bactericidal activity of the tested compounds against the test target at a dose of 50 ppm. A solvent clear water control (QCK) and a fluoxamid control (FP) with an effective content of 50 ppm were also set up.

Test method: suck 50 microliters of the EC mother solution prepared above with a pipette, dissolve it in 2.95 mL of Tween water, and prepare a medicinal solution with an effective concentration of 500 ppm of the compound to be tested. Pipette 1mL of liquid medicine into a sterilized petri dish, then put 9mL of PDA medium, shake well, and cool. Use a hole punch to punch out the circular bacterial cake and pick it to the center of the petri dish with an inoculating needle, then place the petri dish in an incubator at 27°C for cultivation, and measure the colony diameter after 48 to 72 hours. The pure growth of the colony is the difference between the average diameter of the colony and the diameter of the bacterial cake, and the calculation method of the bacteriostatic rate (%) is calculated by referring to the following formula.

The pure growth of the control colony in the above calculation formula refers to the pure growth of the colony under the clear water control (QCK) test.

The bactericidal activity test results are shown in Table 1.

Table 1 Bactericidal activity (% control effect) of each compound at 50 ppm

It can be seen from Table 1 that the compounds of the G series are only active against wheat scab, cucumber botrytis, and rice sheath blight, especially the inhibition rate of rice sheath blight, and the inhibitory effects of compounds G3, G5, and G6 can be achieved. above 50. Compound G5 had the best inhibitory effect on wheat scab, reaching 53.6%. In addition to compound G3, the inhibition rate of rice sheath blight reached 54.3%. In addition to inhibiting rice sheath blight by 50%, compound G6 also inhibited cucumber botrytis cinerea by 43.9%.

The content described in this specification is only an enumeration of the realization forms of the inventive concept, and the protection scope of the present invention should not be regarded as being limited to the specific forms stated in the embodiments.

Claims (10)

1. An N- (2-benzamide) -1H-pyrazole-4-carboxamide compound, namely an N- (2-benzamide) -3- (difluoromethyl) -1-methyl-1H-pyrazole-4-carboxamide compound, is characterized in that the structural formula is shown as the formula (I):

in formula (I): r is phenyl or substituted phenyl, the number of the substituent groups on the benzene ring of the substituted phenyl is one or more, and each substituent group is independently selected from halogen, C1-C3 alkyl or C1-C3 alkoxy.

2. A N- (2-benzamide) -1H-pyrazole-4-carboxamide according to claim 1, characterized in that in formula (i) R is one of the following: 2-methylphenyl, 2, 6-dichlorophenyl, 2, 3-dichlorophenyl, 4-methoxyphenyl, 2, 4-dichlorophenyl and phenyl.

3. A process for the preparation of N- (2-benzamide) -1H-pyrazole-4-carboxamides according to claim 1 or 2, characterized by comprising the steps of:

1) heating ethyl difluoroacetoacetate and triethyl orthoformate in an organic solvent A to reflux reaction, concentrating to remove the solvent after the reaction is finished, adding the concentrated residue into a mixed solution of a methylhydrazine aqueous solution and an organic solvent B, stirring and reacting at the temperature of 45-60 ℃, and tracking the reaction process by TLC; after the reaction is finished, carrying out post-treatment on the reaction solution to obtain 1-methyl-3-difluoromethyl-1H-pyrazole-4-ethyl formate shown in a formula (II);

2) adding the 1-methyl-3-difluoromethyl-1H-pyrazole-4-ethyl formate shown in the formula (II) obtained in the step 1) into a NaOH aqueous solution with the mass concentration of 8-12%, stirring and reacting at the temperature of 55-70 ℃ until a reaction liquid system is transparent, naturally cooling to room temperature, adding acid to adjust the pH of the reaction liquid to 1.5-3.0, separating out a solid, performing suction filtration, and drying filter residues to obtain 1-methyl-3-difluoromethyl-1H-pyrazole-4-formic acid shown in the formula (III);

3) heating the 1-methyl-3-difluoromethyl-1H-pyrazole-4-formic acid shown in the formula (III) obtained in the step 2) in thionyl chloride to reflux reaction, concentrating to remove excessive thionyl chloride after the reaction is finished, stirring and reacting the concentrated residue with N-Boc-ethylenediamine and triethylamine in an organic solvent C at room temperature, tracking the reaction process by TLC, distilling and concentrating to remove the solvent after the reaction is finished, and separating the distilled and concentrated residue by column chromatography to obtain (2- (3- (difluoromethyl) -1-methyl-1H-pyrazole-4-carboxamido) ethyl) carbamic acid tert-butyl ester shown in the formula (IV);

4) heating the tert-butyl (2- (3- (difluoromethyl) -1-methyl-1H-pyrazole-4-formamido) ethyl) carbamate obtained in the step 3) and trifluoromethyl acetic acid in an organic solvent D to reflux reaction, tracking the reaction process by TLC, distilling and concentrating to remove the solvent after the reaction is finished, and separating the distilled concentrate by column chromatography to obtain the N- (2-aminoethyl) -3- (difluoromethyl) -1-methyl-1H-pyrazole-4-formamide shown in the formula (V);

5) uniformly stirring and mixing the N- (2-aminoethyl) -3- (difluoromethyl) -1-methyl-1H-pyrazole-4-formamide shown in the formula (V) obtained in the step 4), an organic solvent E and triethylamine, then dropwise adding substituted benzoyl chloride, stirring and reacting at room temperature, tracking the reaction process by TLC, performing rotary evaporation and concentration after the reaction is finished to remove the solvent, and performing column chromatography separation and purification on the rotary evaporation and concentration residue to obtain the N- (2-benzamide) -3- (difluoromethyl) -1-methyl-1H-pyrazole-4-formamide shown in the formula (I);

wherein the number of the substituent groups on the benzene ring of the substituted benzoyl chloride is one or more, and each substituent group is independently selected from H, halogen, C1-C3 alkyl or C1-C3 alkoxy.

4. The process for preparing N- (2-benzamide) -1H-pyrazole-4-carboxamide compound according to claim 3, wherein the organic solvent A in step 1) is acetic anhydride and the organic solvent B is ethanol; the organic solvent C in the step 3), the organic solvent D in the step 4) and the organic solvent E in the step 5) are all dichloromethane.

5. The method for preparing N- (2-benzamide) -1H-pyrazole-4-carboxamide compound according to claim 3, wherein in step 1), the molar ratio of ethyl difluoroacetoacetate, triethyl orthoformate and methylhydrazine is 1: 1.1-1.5.

6. The method for preparing an N- (2-benzamide) -1H-pyrazole-4-carboxamide compound according to claim 3, wherein in step 3), the charging molar ratio of 1-methyl-3-difluoromethyl-1H-pyrazole-4-carboxylic acid represented by formula (III) to N-Boc-ethylenediamine is 1: 1.1-1.5; in the step 4), the feeding molar ratio of the tert-butyl (2- (3- (difluoromethyl) -1-methyl-1H-pyrazole-4-formamido) ethyl) carbamate shown in the formula (IV) to the trifluoromethyl acetic acid is 1: 1.05-1.2.

7. The method for preparing an N- (2-benzamide) -1H-pyrazole-4-carboxamide according to claim 3, wherein in step 5), the molar ratio of N- (2-aminoethyl) -3- (difluoromethyl) -1-methyl-1H-pyrazole-4-carboxamide represented by formula (v) to the substituted benzoyl chloride is 1:1.05 to 1.2.

8. The process for preparing N- (2-benzamide) -1H-pyrazole-4-carboxamide compound according to claim 3, wherein the molar ratio of organic solvent A to ethyl difluoroacetoacetate in step 1) is 2-4: 1, the volume of organic solvent B is 0.3-0.8 ml/mmol based on the amount of ethyl difluoroacetoacetate; the volume dosage of the organic reagent C in the step 3) is 0.5-1.0 ml/mmol based on the amount of the 1-methyl-3-difluoromethyl-1H-pyrazole-4-carboxylic acid shown in the formula (III); the volume usage amount of the organic reagent D in the step 4) is 5-8 ml/mmol based on the substance amount of (2- (3- (difluoromethyl) -1-methyl-1H-pyrazole-4-formamido) ethyl) carbamic acid tert-butyl ester shown in a formula (IV); the volume usage amount of the organic reagent E in the step 5) is 5-8 ml/mmol based on the amount of the N- (2-aminoethyl) -3- (difluoromethyl) -1-methyl-1H-pyrazole-4-carboxamide shown in the formula (V).

9. The method for preparing N- (2-benzamide) -1H-pyrazole-4-carboxamide compound according to claim 3, wherein the eluents for column chromatography in step 3), step 4) and step 5) are mixed solution of ethyl acetate and petroleum ether in a volume ratio of 1: 0.5-2.

10. Use of an N- (2-benzamide) -1H-pyrazole-4-carboxamide compound as claimed in claim 1 or 2 for the preparation of fungicides.