64 results about "Nitro reduction" patented technology

A method for synthesizing mirogabalin besilate. The method comprises the following steps: subjecting a chiral ketene and cyanoacetate to a condensation reaction under the action of ammonium acetate to obtain an unsaturated cyano ester, then subjecting the unsaturated cyano ester and nitromethane to a condensation reaction to obtain a nitro ester, subjecting the nitro ester to high-temperature de-esterification to obtain a chiral nitronitrile, then subjecting same to nitroreduction to obtain a chiral aminonitrile, subsequently hydrolyzing the chiral aminonitrile to obtain a mirogabalin free alkali, and finally salifying the mirogabalin free alkali and benzenesulfonic acid to obtain mirogabalin besilate. In the present invention, a chiral cyclobutane quaternary carbon center is stereoscopically and specifically constructed to obtain a chiral nitro ester having a single stereoscopic configuration, thereby preventing chiral isomer waste generated by chiral isomer resolution, such that chiral column separation or chiral resolution is not required, the production cost is significantly reduced, and the residue of heavy-metal titanium in a product and environmental pollution caused by solid waste heavy-metal titanium are also prevented.

The invention discloses a method for catalyzing and photo-initiating nitro reduction through ferric trichloride, and belongs to the field of pharmaceutical compound synthesis. According to the method, transition metal salt is mainly used as a catalyst for reaction, inorganic acid and organic acid are used as additives, nitryl is reduced into amino under the condition of air or nitrogen, the catalytic efficiency is high, the yield of reduction products is high, the production cost is greatly reduced, and the method is suitable for synthesis and amplification of later compounds and has good application prospects. The method has the advantages of no expensive metal catalyst or reducing agent, simple preparation process, high efficiency, environmental protection, safety and cost saving.

The invention discloses a catalytic system for preparing amine compounds through nitro reduction and application of the catalytic system. The catalytic system comprises an alkaline aqueous solution, a reducing agent and a catalyst, the alkaline aqueous solution is an alkali metal hydroxide aqueous solution; the reducing agent is alkali metal hydroboron and / or alkaline earth metal hydroboron; the catalyst is copper salt lewis acid and / or other lewis acid; the other Lewis acid is selected from one or a combination of more of cobalt salt, ferric salt, zinc salt, manganese salt and palladium salt. When the catalytic system is used for reducing the aromatic nitro-compound, the using amount of a reducing agent is small, meanwhile, the using amount of an organic solvent is reduced, the reaction yield is high, the reaction is milder, and amplified production of the process is facilitated.

The invention relates to the technical field of preparation of cupanicilib, and discloses a novel preparation method of cupanicilib, which comprises the following steps: by taking vanillic acid as an initial raw material, carrying out methyl esterification, nitration, alkylation reaction with N-3-chloropropylmorpholine hydrochloride, ester group hydrolysis, condensation with urea, nitro reduction, intramolecular condensation and condensation with chloroethylamine hydrochloride to obtain cupanicilib. According to the synthetic scheme, the synthetic route is short, the raw materials are easy to obtain, the yield is high, no dangerous reaction process exists in the reaction process, a highly toxic reagent is not used, and the synthetic scheme is green and efficient.

The invention discloses a synthesis method of 5-(1H-pyrrole-1-yl)-2-mercaptobenzimidazole, which comprises the following steps: carrying out cyclization condensation reaction on o-phenylenediamine and thiourea in an acidic environment provided by hydrochloric acid to obtain 2-mercaptobenzimidazole; the preparation method comprises the following steps: carrying out nitration reaction on 2-mercaptobenzimidazole, sulfuric acid and nitric acid to obtain 2-mercapto-5-nitrobenzimidazole; the preparation method comprises the following steps: carrying out nitro reduction reaction on 2-sulfydryl-5-nitrobenzimidazole and hydrogen under the catalysis of nickel to obtain 5-amino-2-sulfydryl benzimidazole; the preparation method comprises the following steps: carrying out an N-alkylation reaction on 5-amino-2-mercapto benzimidazole and tetrahydro-2, 5-dimethoxyfuran under the catalysis of copper chloride to generate 5-(1H-pyrrole-1-yl)-2-mercapto benzimidazole, and carrying out a reaction on the 5-amino-2-mercapto benzimidazole and tetrahydro-2, 5-dimethoxyfuran to generate the 5-(1H-pyrrole-1-yl)-2-mercapto benzimidazole. The method disclosed by the invention has the outstanding advantages of mild and easily-controlled conditions, simple and convenient post-treatment, high yield, economy, environmental protection, suitability for large-scale production and the like, conforms to the green chemical development concept, and has important application value.

The invention discloses a synthesis method of Olrabatinib, which comprises the following steps: by taking 2-methyl-5-nitro trifluorotoluene as a raw material, carrying out a Waller-Ziegler reaction, an alkylation / silanization reaction of amine, nitro reduction, a condensation reaction and a Caslow-Stevens coupling reaction, so as to obtain the Olrabatinib. By optimizing process conditions and a reaction system, the synthesis method disclosed by the invention has the remarkable advantages in the following aspects: the raw material cost is greatly reduced by adopting low solvent consumption; the product yield is improved by accurately controlling reaction parameters; a standardized post-treatment process is developed, and large-scale stable production is realized. According to the technical system, the technical bottlenecks of high energy consumption and high pollution in the traditional synthesis route are effectively solved, and an innovative solution is provided for green manufacturing of fine chemicals.

The application discloses a synthesis process of (-)-alpha-lycorane alkaloid and belongs to the technical field of organic synthesis chemistry. (2Z,4E)-7,7-diethoxy-3-hydroxyhepta-2,4-dienoic acid methyl ester and 3,4-methylenedioxy-beta-nitrostyrene are used as starting materials, and (-)-alpha-lycorane is obtained through catalytic asymmetric tandem Michael addition reaction, nitro reduction amination reaction, Boc amidation reaction, Bischler-Napieralski cyclization reaction, ketone enolization tandem esterification reaction, enol triflate reductive hydrogenolysis reaction and amide reduction reaction in sequence. (-)-Alpha-lycorane has a four-membered ring core skeleton of pyrrole-phenanthridine ring, has good in-vitro tumor inhibition activity and cell proliferation growth inhibition activity. The synthesis process can realize efficient, simple and full synthesis of (-)-alpha-lycorane.

The invention discloses a method for preparing nanoscale ammoniated aramid fibers through reduction after mixed acid nitration, and belongs to the technical field of chemistry and materials. The method comprises the following steps: by taking waste aramid fiber as a raw material, converting the aramid fiber into nitrified aramid fiber by utilizing nitroxyl positive ions in mixed acid; and reducing nitryl groups on the nitrated aramid fibers into amino groups by utilizing a relatively cheap tin tetrachloride catalyst under a mild condition, so as to successfully prepare the ammoniated aramid fibers. The method for preparing the nanoscale ammoniated aramid fiber through reduction after mixed acid nitration has the following advantages that operation is easy and convenient, cost is low, and industrial production is facilitated; (2) the reaction temperature is low, the experiment condition is mild, and the sustainability is realized; (3) the reaction is fast, and the period is short; and (4) the product is convenient to collect, and subsequent use is facilitated.

The application discloses a synthesis method of a trident connecting segment which can be used for improving hydrophilicity of an antibody drug conjugate, and relates to the field of organic synthesis. The {[5-amino-2-(3,3,4,4-tetramethyl-2-oxa-3-silapent-1-yl)phenyl]methyl}(methyl)amino)methane acid-2-methylpropan-2-yl ester can be used for connecting a hydrophobic dipeptide, a hydrophilic chain and a small molecule drug in an ADC drug, so as to prolong the action time of the ADC drug. The application takes cheap and easily obtained commercial raw material 2-bromo-5-nitrobenzaldehyde as a starting raw material, and successfully prepares the target product through seven steps of conventional transformation such as reduction amination, protection, coupling, ozonation and nitro reduction, with a total yield of about 60% and a scale of hundreds of grams. The starting raw material is cheap, the operation and treatment are simple, and the reaction condition is mild, so that the application is a brand-new process synthesis route, and has good economic benefits and market prospects.

The application provides a preparation method of bumetanide, taking p-chlorobenzoic acid as a starting material, performing chlorosulfonation, nitration, and ammonolysis to obtain a key intermediate of 3-(N-(tert-butyl) sulfamoyl)-4-chloro-5-nitrobenzoic acid, then performing phenoxylation, nitro reduction, n-butylation, and tert-butyl removal, and finally obtaining the bumetanide. Compared with the synthesis process of the prior art, the method has less side reactions, low cost, high yield, high safety, and is beneficial to industrial production.

The invention relates to a preparation method and application of an N-alkyl amide natural product Cubebamide and an analogue thereof, and belongs to the field of compound technologies and medicinal chemistry. According to the invention, commercially available 3, 4, 5-trimethoxybenzaldehyde 1 is used as a raw material, a compound 3 is obtained through a Horner-Wadsworth-Emmons (HWE) reaction, and then a compound 4 is obtained through hydrolysis. A compound 5a-5f is used as a raw material, a compound 6a-6f is synthesized through a Henry reaction, and a compound 8a-8f is obtained through double bond and nitro reduction. And carrying out condensation reaction on the two fragments 4 and 8a-8f to obtain the natural product Cubebamide and the analogue 9a-9f thereof. The compounds 9a, 9c and 9d disclosed by the invention have relatively good anti-inflammatory activity; the compounds 9b, 9e and 9f have remarkable anti-inflammatory activity. The synthesis method has the advantages of easily available raw materials, mild reaction conditions, environmental protection and simple operation.

The invention relates to the technical field of organic synthesis, in particular to a preparation method of hydrogen-containing silane mediated benzoxazole derivatives, which comprises the following steps: (2-nitrophenyl) benzoate and analogues thereof as nitro substrates are dissolved in acid liquor with a palladium catalyst, hydrogen-containing silane is slowly injected, reaction is carried out under normal pressure, after the reaction is finished, a reaction product is subjected to post-treatment, and the hydrogen-containing silane mediated benzoxazole derivatives are obtained. Separating and purifying to obtain a target product benzoxazole derivative. The novel synthesis method of benzoxazole and derivatives thereof is adopted, high-pressure hydrogen and inert gas protection required by a traditional hydrogenation method is abandoned, nitro reduction and cyclization are completed in one step, and a safe, economical and environment-compatible synthesis scheme is provided for large-scale production of benzo-azacyclo drug intermediates.

The invention provides an omariglitazone intermediate, a preparation method thereof and a method for preparing an omariglitazone key intermediate, and relates to the technical field of organic chemistry. The omarignelone intermediate provided by the invention has a structure as shown in a formula VIII; the omariglitazone intermediate is easy to obtain and can be conveniently prepared by taking benzaldehyde as a starting raw material, a chiral chromatographic column does not need to be used for preparation of the omariglitazone intermediate, a key chiral center of the omariglitazone intermediate is constructed by catalyzing a cheap chiral amine catalyst through an asymmetric Knoevenagel-Michael addition reaction, and the preparation method is simple and convenient. According to the omariglitazone intermediate, industrial production of the omariglitazone key intermediate (the structure as shown in the formula I) is easy to realize, and the production cost is reduced. The invention provides a method for preparing an omariglone key intermediate (a structure shown in a formula I), the omariglone key intermediate can be prepared from the omariglone intermediate through a nitro reduction reaction, a Jappp-Klingemann reaction and an indole synthesis reaction, and the method is suitable for industrial production. A formula VIII and a formula I are shown in the description.

The application discloses a preparation method of 2-acetylamino-4-[(2-hydroxyethyl)sulfonyl]benzoic acid. The 2-acetylamino-4-[(2-hydroxyethyl)sulfonyl]benzoic acid is prepared from 4-fluoro-2-nitrobenzoic acid methyl ester as a starting material through aromatic nucleophilic substitution reaction, nitro reduction reaction, ester hydrolysis reaction, amino acylation reaction, thioether oxidation reaction and the like. The method has the advantages of mild reaction condition, high yield, low cost, easy availability of raw materials, and the like. The synthesis process meets the requirements of green chemistry, the synthesis route is innovative, the reaction post-treatment is simple, and the product is easy to purify.

The invention provides a method for synthesizing 4, 4 '-difluorobenzophenone from p-nitrobenzoyl chloride, and belongs to the field of organic synthesis. The method comprises the following steps: (1) reacting paranitrobenzoyl chloride with aromatic fluoride in the presence of a catalyst to obtain 4-nitro-4 '-fluorobenzophenone; (2) carrying out nitro reduction reaction on the 4-nitro-4 '-fluorobenzophenone obtained in the step (1) to obtain 4-amino-4'-fluorobenzophenone; and (3) carrying out diazotization reaction on the 4-amino-4 '-fluorobenzophenone obtained in the step (2), anhydrous hydrogen fluoride and sodium nitrite, and after the reaction is finished, heating and carrying out cracking reaction to obtain the product 4, 4'-difluorobenzophenone. In the synthesis process, the generation of isomers is avoided, the reaction selectivity is improved, the generation of 4-fluorobenzophenone impurities is reduced, the product purity is improved, and a guarantee is provided for the quality of downstream polyether-ether-ketone products.

The present invention relates to the technical field of camptothecin derivative preparation, particularly to a camptothecin derivative synthesis method, which uses 2-nitroacetophenone and isopropylamine as raw materials, and the camptothecin derivative is obtained through a Mannich reaction, a methylsulfonylation reaction, a nitro reduction reaction and a ring closing reaction. According to the synthetic method of the camptothecin derivative, the complex camptothecin derivative is split into two segments 1-(2-aminophenyl)-3-(N-isopropyl-N-methylsulfonylamino) propan-1-one and a compound V which are easy to prepare, and finally, a plurality of rings and chemical bonds are constructed simultaneously through one-step efficient ring closing reaction. The yield attenuation caused by progressive multiplication of the yield in the traditional linear synthesis is avoided, and the total yield is improved.

The invention relates to a preparation method and a preparation system of quinclorac, and belongs to the technical field of herbicide preparation, AuPd alloy nanoparticles are loaded on a lanthanum-doped CsPMo composite carrier, a'Lewis acid site + electron-rich metal active center 'synergistic system is constructed, lanthanum ions are embedded into Keggin structural gaps of CsPMo through ionic bonds or coordinate bonds, and the quinclorac is prepared. The specific surface area of the composite carrier is remarkably increased, the number of Lewis acid sites is increased, electron metal-composite carrier interaction between an AuPd alloy and the composite carrier induces electrons to be transferred from the carrier to the alloy, an electron-rich active center is formed, an oxygen activation energy barrier is reduced, oxygen ion active oxygen species are efficiently generated, and the catalytic activity of the AuPd alloy is improved. Meanwhile, hydrogen is accelerated to be dissociated into active hydrogen species, sufficient active species are provided for oxidation reaction and reduction reaction respectively, and efficient promotion of methyl oxidation, nitro reduction and subsequent ring closing reaction of 1-chloro-2-methyl-3-nitrobenzene is ensured.

The invention discloses a high-dispersion metal co-doped carbon catalyst and a preparation method and application thereof.The preparation method comprises the steps that S1, organic matter is adsorbed by layered double-metal hydroxide, and organic-carbon-containing micromolecule anchored layered double-metal hydroxide is obtained; and S2, carrying out heat treatment on the micromolecular anchoring layered double metal hydroxide containing the organic carbon at the temperature of 600-1400 DEG C. The catalyst is prepared by the method and can be used for catalyzing nitro reduction reaction of aromatic hydrocarbon. The high-dispersion metal co-doped carbon catalyst prepared by the invention has very high catalytic activity, stability and cycle performance, can realize magnetic separation, and is especially suitable for catalysis of reduction reaction of aromatic nitro compounds. The preparation method has the advantages of cheap and easily available raw materials and simple process, and is suitable for large-scale industrial production.

The present invention relates to the field of organic chemical synthesis, and particularly to a preparation method of ornidazole. The preparation method includes four steps: chiral thiourea-catalyzed Henry reaction, Suzuki coupling reaction, nitro reduction reaction, and tetrazole cyclization reaction, to obtain the target product with high yield and enantioselectivity. This method has good application prospects in the industrial production of ornidazole, is expected to reduce production costs and improve product quality, so as to meet the production requirements.

The invention discloses a method for preparing bio-based isosorbide-based semi-aromatic polyamide by taking isosorbide as a skeleton, and belongs to the technical field of polyamide synthesis. The method comprises the following steps: carrying out aromatic nucleophilic substitution reaction on isosorbide and halogenated nitrobenzene in an alkaline medium to obtain a dinitro compound; reducing nitro in the dinitro compound into amine by using a catalyst to obtain diamine; diamine and binary acid are used as monomers, and the bio-based isosorbide semi-aromatic polyamide is obtained through a solution polymerization method. The molecular main chain of the bio-based semi-aromatic polyamide contains both aromatic rings and aliphatic chains (isosorbide frameworks), so that the bio-based semi-aromatic polyamide has excellent thermal performance of aromatic polyamide and good forming processability of aliphatic polyamide. The solution polymerization method used in the invention has low reaction temperature, effectively inhibits volatilization and decomposition of monomers and side reactions, and improves the product yield.

The invention relates to the technical field of pesticide preparation, and particularly discloses a novel preparation method of a key intermediate 1-(2, 4, 6-trichlorophenyl)-propyl-2-ketone of a bactericide pydiflumetofen. The method comprises the following steps: by taking 3, 5-dichloro-4-fluoronitrobenzene as a starting raw material, sequentially carrying out four-step unit reactions: reacting with ethyl acetoacetate under an alkaline condition to prepare 2-(2, 6-dichloro-4-nitrophenyl)-3-oxobutyric acid ethyl ester, and reacting with ethyl acetoacetate under an alkaline condition to prepare 2-(2, 6-dichloro-4-nitrophenyl)-3-oxobutyric acid ethyl ester; carrying out degreasing under an acidic condition, so as to obtain 1-(2, 6-dichloro-4-nitrophenyl)-propyl-2-ketone; reducing the nitro group to obtain 1-(4-amino-2, 6-dichlorophenyl)-propyl-2-ketone; and performing Sandmeyer reaction to obtain a target product. The preparation method is novel in synthetic route, few in side reaction and high in total yield, the content of a target product is larger than 99%, the preparation method is suitable for industrial production, and a key support is provided for industrialization of pydiflumetofen.

Polyimide containing dibenzofuran (thiophene) and triphenylamine structure and preparation method and application thereof, and application thereof, the present application relates to polyimide containing dibenzofuran (thiophene) and triphenylamine structure and preparation method and application thereof. In order to solve the problem of low solubility of aromatic polyimide in organic solvent, poor optical contrast, slow response time and poor capacitor performance, 2,8-dibromodibenzofuran (thiophene) is used as raw material, and 4-methoxy-4'-nitrodiphenylamine is reacted to obtain a new precursor containing dibenzofuran (thiophene) and triphenylamine structure. The nitro group is reduced to obtain a diamine monomer, which is polymerized with dianhydride to form a new high-performance polyimide. At the same time, the polymer has excellent electrochromic performance, including excellent cycle stability, fast switching time, high optical contrast and low voltage start. It also has excellent capacitor performance, including excellent specific capacity and cycle stability. The present application is expected to be applied in the field of electrochromic supercapacitor.

The present application relates to a preparation method of bumetanide, and belongs to the technical field of pharmaceutical chemistry. The present application takes 4-chlorobromobenzene as a starting material, and is subjected to sulfonylation, nitration, ammonolysis, substitution, cyanation, nitro reduction, alkylation, and finally acidification to obtain bumetanide. In the synthetic route of the present application, the carboxyl group does not need to be protected, but a cyano group which does not need functional group protection is introduced, and finally the cyano group is directly hydrolyzed into a carboxyl group to obtain bumetanide. The present application has few side reactions, the intermediates can be precipitated in water, greatly reducing the solvent cost, being easier to purify, the quality of the intermediates and bumetanide being easy to control, reducing the production risk, and being more beneficial to industrial mass production.

This invention provides a method for synthesizing milobalin benzylsulfonic acid, comprising the following steps: a chiral enone undergoes a condensation reaction with cyanoacetate in the presence of ammonium acetate to obtain an unsaturated cyano ester; next, the unsaturated cyano ester undergoes a condensation reaction with nitromethane to obtain a nitro ester; the nitro ester is then deesterified at high temperature to obtain a chiral nitro nitrile, which is then reduced to a chiral amino nitrile; subsequently, the chiral amino nitrile is hydrolyzed to obtain the free base of milobalin; finally, the free base of milobalin is salted with benzylsulfonic acid to obtain milobalin benzylsulfonic acid. This invention stereospecifically constructs a chiral cyclobutane quaternary carbon center to obtain a chiral nitro ester with a single stereoconfiguration, avoiding the chiral isomer waste generated by chiral isomer resolution, eliminating the need for chiral column separation or chiral resolution, significantly reducing production costs, and simultaneously avoiding the environmental pollution caused by residual heavy metal titanium in the product and solid waste heavy metal titanium.

The invention relates to the technical field of medicine synthesis, and particularly discloses a synthesis process of an estrogen regulating medicine. A is used as a starting point of a reaction route, J is prepared through naphthalenone reduction and enol etherification, electron-rich biaryl construction, nitro reduction and benzyl deprotection, secondary amine construction, chiral resolution, acetylation and LAH strong reduction in sequence, all the reaction raw materials are low in price and easy to obtain, the process is stable and mild, the yield is high, and the method has high value for adjusting rapid and mild synthesis of estrogen drugs.

A self-sensitizing negative polyimide precursor and a method for preparing the same, and use thereof. 4,4′-dinitro-1,1′-biphenyl-2,2′-dicarboxylic acid is used as a starting material and undergoes an acylation reaction with thionyl chloride to afford compound 1. Compound 1 subsequently undergoes an esterification reaction with 2-hydroxyethyl methacrylate to afford compound 2. The nitro groups of compound 2 are then reduced to amino groups; after purification, an intermediate of the self-sensitizing negative polyimide precursor is obtained. The intermediate is polymerized with 3,3′,4,4′-benzophenone tetracarboxylic dianhydride to give a polyamic acid, namely the self-sensitizing negative polyimide precursor. Because the intermediate contains a benzophenone moiety, ultraviolet irradiation can generate free radicals, allowing the intermediate to act intrinsically as a photoinitiator. The dual photosensitive properties of the ketone carbonyl and double bond in the self-sensitizing negative polyimide precursor material provided by the present application can improve the exposure sensitivity of the resin.

The present invention discloses a method for photoinduced nitro reduction catalyzed by ferric chloride, belonging to the field of pharmaceutical compound synthesis. The method provided by the present invention primarily utilizes a transition metal salt as a catalyst for the primary reaction, with an inorganic acid or an organic acid as an additive, to achieve nitro reduction to amino groups under air or nitrogen conditions. The method has high catalytic efficiency and a high yield of the reduction product, significantly reducing production costs and being suitable for the synthesis and amplification of later-stage compounds. The method does not require expensive metal catalysts or reducing agents, has a simple preparation process, and is highly efficient, environmentally friendly, safe, and cost-effective.

The invention relates to the field of chemical synthesis, in particular to a synthesis method of 6-bromoindole-2-carboxylic acid. Comprising the following steps: preparing 4-bromo-2-aminotoluene; preparation of 6-bromoindole-2-carboxylic acid ethyl ester; and preparing the 6-bromoindole-2-carboxylic acid. According to the present invention, the reduction cyclization and hydrolysis process is improved, the diethyl malonate is adopted as the mild reducing agent, and the step-by-step temperature control technology is combined so as to significantly improve the yield and the purity; the invention discloses a three-step synthesis process of a bromo-indole carboxylic acid derivative. The method comprises the following steps: 1, in an improved mixed solvent system, carrying out a reduction reaction of reducing nitryl into amino; in the second step, a controllable reduction cyclization technology is adopted, and nitro amination is achieved; in the third step, the ester bond breaking efficiency is improved through the synergistic effect of alkaline hydrolysis and a solvent.

The invention discloses a preparation method of a dabigatran etexilate precursor, and belongs to the technical field of drug intermediate synthesis. The method comprises the following steps: S1, under the protection of nitrogen, reducing nitro of a compound IV into amino by taking tetrahydroxy diboron and 4, 4 '-dipyridyl as a concerted catalytic system, and purifying to obtain a compound III; s2, pretreating a compound III, a compound II and a condensing agent, performing low-temperature activation and microwave reaction in a DMF / DCM mixed solvent in the presence of HATU, HOAt and DIPEA, and performing post-treatment and recrystallization to obtain an amino amide intermediate; and S3, dissolving the amino amide intermediate in glacial acetic acid, carrying out reflux cyclization, and carrying out post-treatment and recrystallization to obtain a compound I. According to the invention, tetrahydroxy diboron and 4, 4 '-dipyridyl are adopted to synergistically catalyze nitro reduction, the conditions are mild, and the reaction is rapid; by means of synergistic catalysis of HATU and HOAt, water removal through a 4molecular sieve, batch addition of HATU, microwave assistance and the like, the reaction time is shortened, the yield is increased, side reactions are reduced, and the method is suitable for industrial production.