264 results about "Reductive amination" patented technology

The invention relates to the technical field of biology, in particular to a leucine dehydrogenase mutant and application thereof. According to the leucine dehydrogenase mutant and the application thereof provided by the embodiment of the invention, wild leucine dehydrogenase is subjected to mutation screening to obtain the leucine dehydrogenase mutant with an amino acid sequence as shown in SEQ ID NO: 1 or SEQ ID NO: 2, the catalytic efficiency of asymmetric reductive amination of a prochiral alpha-keto acid compound is improved, and the thermal stability of the leucine dehydrogenase mutant is improved; the synthesis efficiency of the L-amino acid is favorably improved.

The imine reductase mutant provided by the invention can catalyze asymmetric reductive amination of ethyl 3-formylhexanoate and (S)-2-aminobutanamide to synthesize brivaracetam, two chiral centers of brivaracetam are constructed in one step, and the problems of poor environmental protection property, low atom utilization rate, long route and the like in the existing industrial synthesis route are solved. Wide application prospects are realized.

The application discloses a method for selectively preparing furan amine or tetrahydrofuran amine from furan aldehyde substances, which comprises the following steps: in an aqueous solution with the volume percentage concentration of ammonia water being greater than 70%, furan aldehyde substances are subjected to a reductive amination reaction in the presence of H2 and under the action of a catalyst to prepare furan amine; and in an aqueous solution with the volume percentage concentration of ammonia water being less than 20%, furan aldehyde substances are subjected to a reductive amination reaction in the presence of H2 and under the action of a catalyst to prepare tetrahydrofuran amine. The method can realize the selectivity of products by changing the addition amount of ammonia water in the aqueous solution, and is simple, easy to control, and suitable for industrial production and market promotion and application.

The invention provides a preparation method and intermediates of alasset hydrochloride, which comprises the following steps: reacting an initial raw material as shown in a formula 1, which is protected by bare phenolic hydroxyl groups or different protecting groups, with bis (pinacolato) diboron to obtain an intermediate as shown in a formula 2, carrying out coupling reaction on the intermediate and a compound as shown in a formula 3 to obtain a corresponding hydroxyl-protected intermediate as shown in a formula 4, and separating and purifying the intermediate to obtain the alasset hydrochloride. The preparation method comprises the following steps: carrying out catalyst pressurized hydrogenation, carrying out asymmetric chiral hydrogenation to obtain an intermediate as shown in a formula 5, carrying out substitution or reductive amination to obtain an intermediate as shown in a formula 6, carrying out nucleophilic substitution on the intermediate as shown in a formula 7 to obtain an intermediate as shown in a formula 8, and carrying out deprotection to obtain a target product as shown in a formula I. According to the invention, a chiral resolution link in the existing preparation technology is avoided, and a chiral group is introduced through asymmetric hydrogenation, so that the yield is greatly improved, the production cost is greatly reduced, the tedious and tedious synthesis steps in the original process are shortened, and the post-treatment is simpler and more controllable.

The invention discloses a method for preparing furfuryl amine by reductive amination of biomass-based furfural, which comprises the following steps: adding furfural, a catalyst, ammonia water and a solvent into a closed reaction kettle in proportion, replacing air in the reaction kettle with high-purity hydrogen, and reacting in an oil bath pan for a period of time to obtain a target product furfuryl amine, the nano-catalyst provided by the invention is a nitrogen-doped porous hollow carbon sphere loaded nano bimetallic catalyst, takes noble metal and non-noble metal as a metal active center together, and has adjustability of macroscopic size and microstructure at the same time; the method has the advantages of simple reaction system, mild conditions, no pollution to the environment, high efficiency, energy conservation, low cost, few byproducts, high yield, high selectivity and the like, the furfural is efficiently converted into furfuryl amine at low temperature and low pressure within a short time, the used heterogeneous catalyst is stable and easy to recover, a new thought and direction are provided for enterprise production and scientific research, and the method is suitable for industrial production. The method has great significance on development and utilization of biomass-based furfural.

The invention discloses a method for preparing cyclohexylamine based on reductive amination of cyclohexanone, and belongs to the technical field of fine chemical engineering. The preparation method comprises the following steps: adding a reactant cyclohexanone into a reaction kettle containing a certain amount of solvent, ammonia water and hydrogen atmosphere, and carrying out reductive amination reaction in the presence of a catalyst to obtain cyclohexylamine. The catalyst is CoyAl-LDHs loaded with metal active components, the CoyAl-LDHs are layered cobalt-aluminum bimetal hydroxides, and cobalt ions and precious metal ions in laminates are subjected to spontaneous oxidation-reduction reaction, so that the precious metal ions can be efficiently reduced into active metal nanoparticles. The layered cobalt-aluminum double-metal hydroxide not only has abundant surface acid-base sites, but also has high dispersity of loaded metal nanoparticles. The catalyst preparation and reductive amination reaction conditions are mild, the yield is high, the reaction system is simple and easy to separate, and the method is suitable for industrial production of cyclohexylamine.

The invention provides an alpha, beta unsubstituted 1, 4-ketoaldehyde compound and a metal-free photocatalytic aqueous solution acetaldehyde alpha-position selective single alkylation reaction preparation method and application thereof, a photosensitizer and alpha bromine / chloro aryl ethyl ketone are mixed in an organic solvent, then TEEDA, nBu4NI and an acetaldehyde aqueous solution are sequentially added, white light irradiation stirring reaction, separation and purification are performed, and the alpha, beta unsubstituted 1, 4-ketoaldehyde compound is obtained. Compared with the prior art, the method has the advantages that by improving the light source, the reaction can be amplified to the gram scale level, the yield of the corresponding alpha and beta unsubstituted 1, 4-ketoaldehyde product is not obviously reduced, and a basis is provided for the industrialization process of the reaction. The reaction disclosed by the invention has the characteristics of wide substrate range, high functional group tolerance, simplicity in operation, mild reaction conditions and the like. Moreover, the product disclosed by the invention can be subjected to reductive amination with cyclic secondary amine to obtain a series of gamma-aminoketones with biological activity, which shows that the reaction has potential synthesis application value in the field of pharmaceuticals.

The invention belongs to the technical field of biochemical engineering, and particularly relates to a marine metagenome sourced meso-diaminopimelate dehydrogenase mutant and application thereof in D-tryptophan synthesis. According to the invention, a fast evolution method based on Rosetta guidance is adopted to modify meso-diaminopimelate dehydrogenase from a marine metagenome, and a mutant with high catalytic activity on 3-indolepyruvic acid is obtained through screening. The meso-diaminopimelate dehydrogenase mutant disclosed by the invention can be applied to direct catalysis of reductive amination of 3-indolepyruvic acid to generate chiral D-tryptophan, and can also be coupled with L-amino acid deaminase and coenzyme regeneration enzyme to realize configuration inversion from L-tryptophan to D-tryptophan, the substrate concentration reaches 0.1 M, and the product conversion rate is gt; the ee value is gt; therefore, the method has a relatively high practical application value.

The invention relates to application of a non-noble metal catalyst Cu-ZnO / TiO2 in catalytic synthesis of N, N '-dicyclohexyl p-phenylenediamine in a heterogeneous system, and belongs to the technical field of catalyst preparation and application. According to the catalyst, zinc nitrate hexahydrate serves as a zinc source, copper nitrate trihydrate serves as a copper source, P25 type titanium dioxide serves as a carrier, metal is loaded on titanium dioxide through a fractional precipitation method, the titanium dioxide is put into a tubular furnace for hydrogen reduction, a catalyst Cu-ZnO / TiO2 is obtained, then the catalyst Cu-ZnO / TiO2 is dispersed in a solvent, and the novel rubber anti-aging agent N, N-dimethylformamide is synthesized by catalyzing a photo-thermal reduction amination reaction of p-phenylenediamine and cyclohexanone. The catalyst is N, N '-dicyclohexyl p-phenylenediamine. Wherein the Cu-ZnO / TiO2 catalyst with the content of copper being 7% and the content of zinc oxide being 4% has excellent catalytic performance, the conversion rate of p-phenylenediamine reaches 100% and the selectivity of N, N '-dicyclohexyl p-phenylenediamine reaches 99.9% when the hydrogen pressure is 6 MPa, the temperature is 200 DEG C and the reaction is performed for 10 h. The preparation method is simple, low in cost and high in catalytic selectivity, and has a wide industrialization prospect.

The invention relates to the field of organic chemistry, and particularly discloses a synthetic method of berberine hydrochloride. The synthesis method of berberine hydrochloride comprises the following steps: S1, carrying out reductive amination reaction on bromohomopiperony lamine and o-veratraldehyde to synthesize an intermediate II; s2, carrying out Suzuki coupling reaction on the intermediate II and an organic boron compound under the catalysis of a palladium metal organic matter to synthesize an intermediate III; s3, the intermediate III and organic chloride are subjected to an amino chlorination reaction, and an intermediate IV is synthesized; s4, carrying out intramolecular atom transfer radical addition and intramolecular Friedel-Crafts alkylation cascade reaction on the intermediate IV in a mixed solvent under the catalysis of a copper catalyst to synthesize an intermediate V; and S5, carrying out oxidative aromatization reaction on the intermediate V and iodine under the catalysis of alkali to synthesize berberine hydrochloride. The synthesis process is simpler, reaction conditions are easier to control, the yield is high, and the method is suitable for industrial production.

The invention belongs to the technical field of catalysts, and particularly relates to a catalyst, a preparation method thereof and application of the catalyst in synthesis of primary amine compounds. The preparation method of the catalyst comprises the following steps: dissolving Ni (NO3) 2 and terephthalic acid in a solvent, uniformly mixing, carrying out a hydrothermal reaction at a certain temperature to obtain Ni-MOF, washing, drying, and reducing in an H2 / Ar atmosphere to obtain the catalyst Ov-NiO / Ni-C-T (X) (wherein T represents the reduction temperature, the unit is DEG C, and X represents the reduction time, the unit is h). The preparation method of the catalyst is simple, the catalyst can be recycled for 7 times without obvious loss of catalytic activity and selectivity, and the catalyst has high catalytic activity for synthesis of primary amine through reductive amination of aldehyde compounds and ketone compounds.

The invention belongs to the technical field of asymmetric catalysis, and discloses a chiral phosphine nitrogen-nitrogen tridentate ligand based on a ferrocene skeleton as well as a preparation method and application of the chiral phosphine nitrogen-nitrogen tridentate ligand. The structural formula of the ligand is shown as (I) or an enantiomer (II) of the ligand. The preparation method comprises the steps of acylation reaction, oxazoline ring construction, aldehyde group introduction, reductive amination and the like, and application in asymmetric hydrogenation reaction, such as asymmetric hydrogenation of aryl ketone. The ligand has a plurality of chiral factors, simultaneously has a potential hydrogen bond donor, forms secondary interaction with a substrate in an asymmetric catalytic reaction, can further stabilize a reaction transition state, is an efficient novel chiral P, N, N-ligand, has the advantages of high reaction activity, good stereoselectivity, wide substrate range and the like, and has a wide application prospect. # imgabs0 #

The invention belongs to the field of pesticide intermediates and product preparation, and particularly relates to a method for preparing trifluorobenzene pyrimidine. The method disclosed by the invention comprises the following steps: (1) in a first organic solvent, carrying out Schiff base condensation reaction on 2-aminopyridine and pyrimidine-5-formaldehyde under the action of a first moisture scavenger to generate N-2-pyridine-5-pyrimidine methylenimine; (2) in a second organic solvent, carrying out reductive amination reaction on the N-2-pyridine-5-pyrimidine methylenimine and hydrogen under the action of a catalyst to generate N-2-pyridine-5-pyrimidine methylamine; and (3) in a third organic solvent, carrying out cyclization reaction on the N-2-pyridine-5-pyrimidine methylamine and 2-(3-trifluoromethylphenyl) malonyl chloride in the presence of an acid-binding agent, so as to prepare the trifluorobenzene pyrimidine. According to the method disclosed by the invention, the post-treatment operation times and the reaction reagent consumption are greatly reduced, and efficient and green production is realized.

The invention discloses a glucan modified bionic nanoparticle as well as a preparation method and application thereof. Preparing nanoparticles based on PLGA as an inner core; the tumor cell membrane is extracted from B16F10 melanoma cells and is used as an outer capsid; glucan is coupled with a hydrophobic long chain through reductive amination and is modified on the surface of a biomimetic nanoparticle cell membrane through a hydrophobic effect. The dextran nano delivery system is successfully constructed, cell membrane specific antigens and dextran are efficiently and jointly delivered to lymph nodes, tumor cell membranes provide epitopes for immune activation of nanoparticles, and beta-dextran provides molecular support for nanoparticle targeting immune cells. In-vivo and in-vitro activity experiments prove that the glycolipid modified bionic nanoparticles can effectively activate innate immunity through macrophages and NK cells, can promote dendritic cell antigen presentation, and initiate potent adaptive immune response. The bionic nanoparticles have huge development potential of novel tumor vaccines, and a new thought is provided for immunotherapy of cancers.

The invention discloses preparation and application of a reductive amination catalyst. The preparation method of the catalyst comprises the following steps: step 1, preparing an SrTiO3 carrier; step 2, loading a nickel source into the prepared SrTiO3 carrier to form a nickel-loaded SrTiO3 catalyst precursor; and step 3, roasting the SrTiO3 catalyst precursor to obtain the SrTiO3 loaded nickel catalyst. Large-scale production of the non-noble metal catalyst is realized by adopting a co-precipitation method and an impregnation method which are simple in process and environment-friendly under the condition of room temperature, the obtained material can be used for reductive amination reaction of acetophenone under the condition of taking water as a solvent and shows excellent catalytic performance, and after 50 times of application, the acetophenone conversion rate is gt; the selectivity of alpha-phenylethylamine is gt; the selectivity of the alpha-phenethyl alcohol is 1t; and 2%.

The present invention relates to the technical field of the synthesis of omadacycline, and particularly to a preparation method of omadacycline. The method comprises the following steps: the aminomethyl tetracycline intermediate M2 shown in formula I is subjected to reductive amination to obtain the crude product M3 of omadacycline, and the conditions for the reductive amination are as follows: in the presence of a transition metal catalyst, an organic base and pivalaldehyde, a hydrosilane reducing agent is used as the hydrogen source, the reaction pressure is 98 kPa to 105 kPa, the reaction temperature is 15 to 35 °C, and the reaction time is 0.5 to 48 hours. The present invention provides a safer and more environmentally friendly method for industrial production of its important intermediate, significantly shortening the reaction time, reducing the impurity content in the reaction solution, and greatly reducing the pressure of subsequent purification operations.

The invention provides a preparation method of a supported catalyst, the supported catalyst and application. The preparation method comprises the following steps: precipitating a noble metal Ru precursor and a non-noble metal (Fe, Mn, Cr, Mo and W) precursor on a carrier by adopting a coprecipitation method, and reducing a non-noble metal oxide from a high-valence part to a low-valence part by controlling the ratio and the reduction temperature of the noble metal Ru and the non-noble metal to form high-valence and low-valence coexisting non-noble metal nanoparticles, and the noble metal Ru is in a monatomic dispersed state. Therefore, the preparation method of the supported catalyst provided by the invention has the advantages of simple steps, low cost and no need of complex operation, and is convenient for realizing industrial production. Tests show that when the supported catalyst is applied to hydrogenation reaction of unsaturated aldehyde ketone, hydrogenation reaction of acid and ester, reductive amination reaction of aldehyde and ketone and reductive amination reaction of octanol and hexanediol, the activity and selectivity can be remarkably improved.

An organosilicon compound with amino-functional groups is prepared. A catalyzed reductive amination process for combining an aldehyde-functional organosilicon compound with an amine source and hydrogen produces the amino-functional organosilicon compound.

The invention provides a reductive amination catalyst as well as a preparation method and application thereof, and belongs to the field of catalysis. The invention provides a reductive amination catalyst. The reductive amination catalyst comprises layered Al2O3 and an alloy loaded on the surface of the layered Al2O3, the alloy comprises a nickel element and a non-noble metal element; the non-noble metal elements comprise one or more of Cu, Mg, Ca, Co and Zn. The nickel element and the selected non-noble metal element are alloyed to adjust the charge structure of a metal site, so that excessive hydrogenation of HMF is inhibited during catalysis, it is ensured that only the aldehyde group of HMF is subjected to a reductive amination reaction, and therefore the selectivity of HMFA is improved.

The present invention provides a number of process improvements related to the conjugation of capsular polysaccharides from Streptococcus pneumoniae to carrier proteins. These methods are serotype specific and include acid hydrolysis, the addition of sodium chloride to the reductive amination reaction, and the addition of sucrose to solubilize the polysaccharide. The polysaccharide-protein conjugates prepared using the methods of the present invention can be included in a multivalent pneumococcal conjugate vaccine.

The invention relates to the technical field of water treatment, and discloses a scale inhibition and dispersion agent for treating industrial circulating water and a preparation method thereof.The scale inhibition and dispersion agent is prepared from 2-[(2-aminoethyl) amino] sodium ethanesulfonate, p-hydroxybenzaldehyde, methoxy polyethylene glycol acrylate and beta-cyclodextrin as raw materials. Sodium alkenyl sulfonate long-chain cyclodextrin is obtained through reductive amination, addition and esterification and initiates copolymerization with acrylic acid and itaconic acid to obtain the scale inhibition and dispersion agent of a comb-type structure, and a chelate is dissolved or suspended in a solution through carboxyl, sulfo group and ether group in the structure of the scale inhibition and dispersion agent, so that the effect of effectively dispersing ferric oxide is achieved; polyethylene glycol long chains and beta-cyclodextrin have large steric hindrance and can be stretched, the probability that CaCO3 and BaSO4 crystals collide with each other can be reduced, salt ions and other molecules causing corrosion in a solution are difficult to get close to the metal surface, and the corrosion inhibitor has a good corrosion inhibition effect, is free of phosphorus and environmentally friendly and can be widely applied to an industrial circulating water treatment system.

The invention discloses a chlorpromazine-d6 compound as well as hydrochloride, a preparation method and application thereof, and belongs to the technical field of organic synthesis and analysis detection, the chlorpromazine-d6 compound is 3-(2-chloro-10-phenothiazinyl)-N, N-bis (methyl-d3)-1-propylamine, and the preparation method comprises the following steps: taking 2-chlorophenothiazine as a raw material, adding a catalyst, and reacting at the temperature of 60-80 DEG C for 1-2 hours to obtain the chlorpromazine-d6 compound. Carrying out aza-Michael addition and reductive amination reaction to finally obtain chlorpromazine-d6; the obtained chlorpromazine-d6 is subjected to hydrochloric acid acidification, such that chlorpromazine-d6 hydrochloride is obtained; the invention provides a novel deuterated internal standard substance for analysis and detection. In addition, the invention provides a new process for preparing chlorpromazine-d6 and hydrochloride thereof with proprietary intellectual property rights, the preparation method is novel, and has the advantages of simple operation, mild reaction conditions, short process route, high efficiency, low cost, environmental protection and the like; the obtained chlorpromazine-d6 and the hydrochloride thereof have the advantages of high chemical purity, high deuteration rate, high deuterium atom stability and the like.

The invention provides a non-noble metal alloy catalyst for double-terminal reductive amination reaction of 5-hydroxymethylfurfural and a preparation method thereof, the catalyst is expressed as M1M2M3 / M1M2M3AlOx, M1 represents a component with amination and hydrogenation potential and is one or more of Fe and Co, M2 represents a component with dehydrogenation potential and is one or more of Ni and Cu, M3 represents a metal additive component and is Zn, and M4 represents a component with hydrogenation potential and is one or more of Fe and Co. One or more of Ga; m1M2M3AlOx is used as a carrier, and is a composite metal oxide formed by carrying out topology on M1M2M3Al-LDHs (Layered Double Hydroxides); according to the catalyst, an LDHs material is used as a precursor, and a series of non-noble metal alloy catalysts composed of different elements are prepared based on element adjustability and topological transformation characteristics of LDHs. The catalyst is used for double-end reductive amination reaction of 5-hydroxymethylfurfural, has high catalytic activity and high target product selectivity, and is outstanding in catalytic performance, good in stability and easy to recover and reuse.

A process for producing amines by reductive amination, the process includes introducing a feed stream, the feed stream comprising an amino alcohol and a reducing agent, and hydrogen in a reaction zone of a reactor, and contacting the feed stream with a catalyst in the reaction zone. A hydrogen flow rate into the reaction zone is adjusted, and a product stream comprising ethyleneamines is extracted. The catalyst includes a carrier component selected from alumina, silica, and combinations thereof; and an active component having a first metal, a second metal, and a third metal. The first metal is selected from cobalt, nickel, and copper, the second metal is selected from rhenium, ruthenium, chromium, zinc, sodium, calcium, magnesium, strontium, lithium, potassium, barium, cesium, lanthanum, tungsten, iron, silver, titanium, manganese, aluminum, rhodium, platinum, palladium, iridium, and combinations thereof, and the third metal is niobium.

This application relates to a terphenylamine skeleton compound, its preparation method, and its application, belonging to the field of chemical synthesis technology. The preparation method of the terphenylamine skeleton compound of this application includes the following steps: dissolving 2,4,6-triphenylaniline with thiazole-4-carboxaldehyde or thiophene-3-carboxaldehyde in a solvent, conducting a reductive amination reaction under reducing agent conditions, quenching, extraction, washing, concentration to remove solvent, and purification to obtain the terphenylamine skeleton compound. This application provides a simple and mild synthetic method for the natural active products 5'-phenyl-N-(thiazol-4-ylmethyl)-[1,1':3',1''-terphenyl]-2'-amine and 5'-phenyl-N-(thiophene-3-ylmethyl)-[1,1':3',1''-terphenyl]-2'-amine, which can only be extracted from the secondary metabolites of the marine fungus Aspergillus sp. Furthermore, this method utilizes widely available raw materials, which is beneficial for large-scale industrial production of these natural active products.

The invention relates to a method for producing 2-aminopropane-1-ol from hydroxyacetone by reductive amination using ammonia water and a co-solvent. The method comprises the following steps: mixing hydroxyacetone and ammonia water at a temperature of not more than 20 DEG C to obtain an oxazoline intermediate product; and adding either a solvent alone or a solvent and a second ammonia water to the oxazoline product in the presence of a nickel catalyst and hydrogen, and hydrogenating at a temperature of not more than 90 DEG C and a pressure of not more than 12 barggage to obtain 2-aminopropan-1-ol.

The invention discloses a marine galactooligosaccharide lipid as well as a preparation method and application thereof, and belongs to the field of marine biological resource utilization and drug development. According to the invention, a marine red algae polysaccharide degradation technology and high efficiency of reductive amination aliphatic chain modification are combined together for the first time, and modification of saturated aliphatic chains with different lengths of marine galactooligosaccharides with different polymerization degrees is realized. Cellular level pharmacodynamic evaluation proves that the marine galactooligosaccharide lipid can significantly inhibit release of nitric oxide in microglial cells and expression of inflammatory factors such as interleukin-6 and tumor necrosis factor alpha, and has neuroinflammation inhibition activity; meanwhile, proliferation of tumor cells U87MG and GL261 can be remarkably inhibited, and the compound has certain anti-tumor potential and can be used for preparing drugs for preventing and / or treating neuroinflammation and anti-tumor related diseases. Therefore, the marine galactooligosaccharide lipid prepared by the invention has relatively high clinical application value and development prospect.

The invention discloses a method for synthesizing a pyrrolidone compound by reductive amination of biomass-based levulinic acid and derivatives thereof, which comprises the following steps: taking a stainless steel high-temperature reaction kettle as a reaction container, respectively adding 0.5-20 mmol of biomass-based levulinic acid or derivatives thereof, 10-200 mg of catalyst and 0.1-1 mL of ammonia water into 5-10 mL of solvent, and sealing the reaction container, the mass concentration of the ammonia water is 28%; the method comprises the following steps: introducing hydrogen into a stainless steel high-temperature reaction kettle, pressurizing to 0.1-5 MPa, reacting at 40-120 DEG C for 0.1-8 hours, putting the reaction kettle into water, cooling to room temperature, deflating, additionally adding 0.5-5 mmol of toluene as an internal standard, and carrying out solid-liquid separation by using a needle type organic filter to obtain the target product 5-methyl-N-methyl-2-pyrrolidone. The method has the advantages of simple reaction system, mild conditions, no pollution to the environment, high efficiency, energy saving, low cost, few byproducts, high yield and high selectivity, and can realize green closed loop from raw materials to products.

The invention discloses an efficient synthesis method of ephedrine hydrochloride, and belongs to the technical field of pharmaceutical chemistry synthesizing.A self-synthesized chiral zinc oxide nanoflower composite catalyst is added in the synthesis process of the ephedrine hydrochloride, and the composite catalyst has a chiral function, is large in pore and surface area, easy to recover and not prone to blockage, and can be used for preparing a chiral zinc oxide nanoflower catalyst. Compared with a traditional Lewis acid type catalyst, the catalyst has the advantages that keto groups in ephedrine hydrochloride synthesis can be precisely reduced, and hexadecyl trimethyl ammonium bromide is intercalated on the surface, so that the catalyst is not easy to agglomerate in a catalytic system, and the yield of a product is further improved; according to the composite catalyst, through hexadecyl trimethyl ammonium bromide, the surface hydrophilicity and hydrophobicity of the composite catalyst are regulated and controlled, the composite catalyst is dispersed more uniformly and makes contact with a compound II more sufficiently, the speed and selectivity of a reductive amination reaction are improved, and the hexadecyl trimethyl ammonium bromide can intercalate mica lamellas, so that the mica lamellas are peeled off, the interlayer spacing is increased, and therefore the composite catalyst is more stable in performance. And the reaction sites are increased, so that the catalytic active center is loaded more stably.

The invention provides an environment-friendly method for preparing a raw material medicine trimetazidine. 2, 3, 4-trimethoxybenzaldehyde and piperazine are used as raw materials, water is used as a solvent, and the trimetazidine is prepared in one step through reductive amination catalyzed by an iridium, manganese or rhenium catalyst. The synthesis method provided by the invention is mild in reaction condition, simple in step, simple to operate, green and environment-friendly, high in synthesis efficiency and convenient to separate and purify, has an industrial application prospect, and plays a positive role in the fields of organic synthesis, medicine production, fine chemical engineering and the like.