56 results about "Ester hydrochloride" patented technology

The invention belongs to the field of detection and analysis, and relates to a method for separating and detecting enantiomers in (S)-2-amino-3-[2-(tert-butoxy)-2-oxoacetamido] tert-butyl propionate hydrochloride. According to the method, HPLC is adopted for separation and detection, a polysaccharide derivative chiral chromatographic column is selected as a chromatographic column, a mobile phase A is a weak base aqueous solution, and a mobile phase B is acetonitrile and / or methanol. The method is strong in specificity, high in separation degree, high in accuracy, stable, reliable and high in sensitivity, and a simple, accurate, rapid and reliable detection method is provided for control of impurities in a starting material of (S)-2-amino-3-[2-(tert-butoxy)-2-oxoacetamido] tert-butyl propionate hydrochloride.

The invention provides a method for synthesizing N-methylated polypeptide, which comprises the following steps: dissolving a carboxylic acid compound, N-methyl amino-acid ester hydrochloride or N-methyl amino-acid ester, an alkaline substance and pivaloic anhydride in an organic solvent, reacting at 15-80 DEG C for 3-10 hours, and post-treating the obtained reaction liquid to obtain an N-methyl dipeptide compound, the method comprises the following steps: removing a protecting group in an N-methyl dipeptide compound to obtain a free-state N-methyl dipeptide compound, and condensing the free-state N-methyl dipeptide compound and amino acid or N-methyl amino-acid ester protected by amino to obtain the N-methylated polypeptide, the mixed anhydride intermediate is formed in situ, and the reaction is completed in one step; according to the method, trimethylacetic anhydride is used as a condensing agent, the structure is simple, the reaction is safe, cheap and non-toxic, a large amount of nitrogen-containing byproducts are not generated in the reaction, and purification is convenient; the method is high in stereoselectivity, and racemization is avoided; according to the method, environment-friendly solvents such as ethyl acetate can be used, the reaction condition is mild, and the reaction time is short.

The present invention relates to polymorphs of the hydrochloride salt of 5-{2-[({8-[(2,6-dimethylbenzyl)amino]-2,3-dimethylimidazo[1,2-a]pyridine-6-yl}carbonyl)-amino]ethoxy}-5-oxopentanoic acid (linaprazan glurate), more specifically Form 1 and Form 2 of the HCl salt of linaprazan glurate. The invention also relates to a process for the preparation of such polymorphs, to pharmaceutical compositions comprising such polymorphs, and to the use of these polymorphs in the treatment or prevention of gastrointestinal inflammatory diseases or gastric acid related diseases, in particular erosive gastroesophageal reflux disease (eGERD).

The invention discloses an antifouling elastic sofa fabric and a preparation method thereof, and relates to the technical field of fabrics. Diphenylmethane diisocyanate, polypropylene oxide glycol and modified silicon dioxide are subjected to surface reaction to prepare a nano waterproof finishing agent, and the modified silicon dioxide is prepared by modifying sodium hydroxide, so that the antistatic effect of the fabric can be improved; dL-3-fluorophenylalanine methyl ester hydrochloride is grafted to cotton fibers, fluorine-containing groups of the DL-3-fluorophenylalanine methyl ester hydrochloride are greatly enriched on the surface of the fabric, the low surface energy of the fabric is reduced, stains are prevented from being attached to the surface of the fabric, the antifouling effect is achieved, meanwhile, DL-3-fluorophenylalanine methyl ester hydrochloride can be bonded with the nano waterproof finishing agent, a net-shaped cross-linked structure is formed, and the anti-fouling effect is achieved. The nano waterproof finishing agent is adsorbed into fibers of the fabric, so that the waterproof and antifouling effects of the fabric are further improved. The fabric prepared by the invention has waterproof and antifouling effects.

The invention provides a method for detecting chloroethane in hexyl aminolevulinate hydrochloride and application, the method comprises the following steps: preparing a reference solution and a test solution, the reference solution is a standard chloroethane solution, and the test solution is a hexyl aminolevulinate hydrochloride solution containing chloroethane; respectively injecting the reference solution and the test solution into a GC-MS (Gas Chromatography-Mass Spectrometer) by adopting a headspace sampling mode, and recording chromatograms; calculating the content of chloroethane in the test sample according to a peak area by an external standard method; the used gas chromatographic column is DB-FFAP, and the adopted gas chromatographic determination conditions are as follows: the flow of the chromatographic column is 1-10ml / min; the initial temperature of the column temperature is 25-50 DEG C, the initial temperature is maintained for 1-10 minutes, and the initial temperature is increased to 150-250 DEG C at the rate of 10-50 DEG C / min and maintained for 1-10 minutes; the temperature of a sample inlet is 150-30 DEG C; the sample size is 0.5 to 5 ml; the mass spectrum conditions are as follows: the operation time is 5-20 minutes; and the mass-to-charge ratio of chloroethane is 64 and 66. The method can be used for accurately and quickly detecting the content of chloroethane in hexyl aminolevulinate hydrochloride.

To provide a stable crystalline form of linaprazan glurate.SOLUTION: Provided are polymorphs of the hydrochloride salt of 5-{2-[({8-[(2,6-dimethylbenzyl)amino]-2,3-dimethylimidazo[1,2-a]pyridine-6-yl}carbonyl)amino]ethoxy}-5-oxopentanoic acid (linaprazan glurate).SELECTED DRAWING: None

The invention provides a synthesis method of a medical intermediate (3R, 5R)-3-Boc-amino-5-fluoropiperidine, which comprises the following steps: step S1, trans-4-hydroxy-D-proline methyl ester hydrochloride is used as a raw material, under the action of triethylamine, a reaction is carried out for 2-4 hours, and the reaction product is subjected to post-treatment to obtain the (3R, 5R)-3-Boc-amino-5-fluoropiperidine. Dichloromethane is used as a solvent to react with triphenylchloromethane to obtain (4S)-4-hydroxy-1-(triphenylmethyl)-D-proline methyl ester; s2, the (4S)-4-hydroxy-1-(triphenyl methyl)-D-proline methyl ester is subjected to oxidation, and 4-oxy-1-(triphenyl methyl)-D-proline methyl ester is obtained; s3, enabling the compound 4-oxo-1-(triphenyl methyl)-D-proline methyl ester to react with hydroxylamine hydrochloride, so as to obtain a compound hydroxylamino-1-(triphenyl methyl)-D-proline methyl ester; step S9, the compound (3R, 5R)-3-Boc amino-1-triphenyl-5-fluoropiperidine is subjected to Trt removal under the action of hydrochloric acid, and a compound (3R, 5R)-3-Boc amino-5-fluoropiperidine is obtained; according to the method disclosed by the invention, the (3R, 5R)-3-Boc amino-5-fluoropiperidine can be efficiently and economically synthesized by optimizing a reaction route.

The invention discloses a preparation method of (2R, 3S)-2-Boc amino-3-hydroxy-3-(pyridine-4-yl) alanine, and belongs to the technical field of medical intermediates. The preparation method comprises the following steps: by taking glycine ester hydrochloride as a raw material, carrying out benzophenone dimethyl ketal reaction to generate a glycine ester imine intermediate; then, the 2-amino-3-hydroxyl-3-(pyridine-4-yl) alanine and pyridine-4-formaldehyde are subjected to acidolysis, and 2-amino-3-hydroxyl-3-(pyridine-4-yl) alanine is generated; then, the 2-Boc amino-3-hydroxyl-3-(pyridine-4-yl) alanine is subjected to a reaction with Boc2O, and a 2-Boc amino-3-hydroxyl-3-(pyridine-4-yl) alanine racemate is generated; and finally, salifying and resolving by adopting a cyclohexanedibenzylamine resolving agent, and then dissociating to obtain a target product. The raw materials are available in the market, direct condensation reaction is performed between pyridine-4-formaldehyde and amino acid imine, effective resolution can be performed by adopting 0.5 eq of a resolution reagent, and the whole route is simple and convenient to operate and suitable for large-scale production.

The invention discloses a 3-ester-1, 3-quinazoline-2, 4-diketone compound and a preparation method and application thereof.The 3-ester-1, 3-quinazoline-2, 4-diketone compound is prepared by the steps that amino-acid ester hydrochloride and isatoic anhydride serve as raw materials and react in acetonitrile under the action of potassium carbonate to generate an amide ester compound; and then reacting the amide ester compound with triphosgene under the action of triethylamine to obtain the 3-ester-1, 3-quinazoline-2, 4-diketone compound. Raw materials for synthesis of the compound are cheap and easy to obtain, the synthesis method is simple, meanwhile, the compound has good bacteriostatic activity on crop germs, especially has a remarkable activity inhibition effect on germs such as gibberellic disease bacteria, phytophthora germs, pyricularia grisea, sclerotinia sclerotiorum, botrytis cinerea and rhizoctonia solani, and the yield of crops is well guaranteed.

The application belongs to the technical field of chemical industry, and discloses a synthesis method and application of (2R,4S)-4-hydroxypyrrolidine-2-carboxylic acid methyl ester hydrochloride, wherein trichloroisocyanuric acid is used as an oxidant, and silica gel loaded 2,2,6,6-tetramethylpiperidine oxide is added as a novel supported catalyst; the supported catalyst is removed and recovered through filtration to obtain an oxidation product IM1; then, sodium triacetoxyborohydride is used as a reducing agent to reduce a trans chiral ketone carbonyl to obtain a trans amino acid product IM2 which cannot be obtained through a fermentation method; finally, the target product (2R,4S)-4-hydroxypyrrolidine-2-carboxylic acid methyl ester hydrochloride is synthesized through a one-step synthesis method under a heating reaction condition in a methanol system. The product prepared through the method has high purity, low raw material cost, simple operation, and is suitable for industrial production and can meet the needs of the future medical and other fields.

The application discloses a tissue adhesive and a preparation method and application thereof, and belongs to the field of medical materials.The tissue adhesive comprises a copolymer composed of at least one of acrylic acid and methacrylic acid and a hydrochloride salt, the hydrochloride salt is at least one of 2-aminoethyl methacrylic acid ester hydrochloride and 2-aminoethyl acrylic acid ester hydrochloride, and the tissue adhesive can further comprise a crosslinked polymer formed by crosslinking at least one of polyacrylic acid and polymethacrylic acid with a polymer, and the polymer is formed by polymerization of the hydrochloride salt and a zwitterionic betaine.The copolymer can quickly absorb moisture on a wet tissue surface to form a gel and adhere to the tissue surface, so that a soft tissue wound, especially a low-pH microenvironment soft tissue wound, is closed; and the crosslinked polymer can be firmly combined on the surface of the copolymer and quickly form an anti-adhesion gel, which effectively prevents the surrounding tissue from being adhered after an operation as a physical barrier.

The invention provides a synthesis method of celacarburine and a key intermediate thereof, which comprises the following steps: taking methyl 4-aminobutyrate hydrochloride as an initial raw material, and sequentially carrying out o-nitrobenzenesulfonyl protection, alkylation, amide condensation, hydrolysis and deprotection, intramolecular cyclization, removal of o-nitrobenzenesulfonyl protecting group and optional acylation reaction to obtain a target product. A synthetic route is designed through an innovative strategy, the technical bottlenecks that raw materials and reagents are difficult to obtain, steps are tedious, conditions are harsh, the yield is low and the like which commonly exist in an existing macrocyclic synthesis method are overcome, and the target product is simply and safely prepared in a high-yield mode under the mild condition. The method has the advantages of cheap and easily available raw materials and reagents, simple operation, mild conditions and no need of special equipment, has significant industrial application potential, and provides a stable and reliable material basis for subsequent pharmacological research and new drug development of celacarflurine.

The application provides a synthesis method of celacarfurine and key intermediates thereof, comprising the following steps: taking 4-amino butyric acid methyl ester hydrochloride as a starting material, sequentially performing ortho-nitrobenzenesulfonyl protection, alkylation, amide condensation, hydrolysis and deprotection, intramolecular cyclization, deprotection of ortho-nitrobenzenesulfonyl, and optional acylation to obtain a target product. The synthesis route is designed by an innovative strategy, and overcomes technical bottlenecks such as difficulty in obtaining raw materials and reagents, long steps, harsh conditions and low yield which exist in the existing macrocycle synthesis method, and the target product is prepared under mild conditions with high yield, simplicity and safety. The method is simple in operation, mild in conditions, and does not need special equipment, has significant industrial application potential, and provides a stable and reliable material basis for subsequent pharmacological research and new drug development of celacarfurine.

The invention belongs to the field of chemical synthesis, and particularly relates to a synthetic method of azetidine-2-yl (methyl) benzyl carbamate hydrochloride. According to the invention, 1-benzyl azetidine-3-alcohol is used as a basic raw material, and a series of reactions such as substitution reaction and the like are carried out to obtain the high-yield and high-purity azetidine-2-yl (methyl) benzyl carbamate hydrochloride, and the method is suitable for industrial production.

This invention provides a method for preparing (S)-2-amino-4-chlorobutyric acid alkyl ester and its salt, comprising the following steps: (1) reacting a compound of formula I with a base to generate a compound of formula II; (2) reacting a compound of formula II with a chlorinating agent to generate a dichloride; and (3) reacting the dichloride with an alcohol to generate a compound of formula III. The preparation method of this invention improves the physicochemical properties of the reaction by constructing a dimer intermediate from the intramolecular bifunctional group of the compound of formula I, then achieving hydroxyl chlorination with a chlorinating agent, and finally, under the action of an alcohol, achieving the one-pot preparation of (S)-2-amino-4-chlorobutyric acid alkyl ester hydrochloride. This method effectively reduces the amount of chlorinating agent and alcohol used, significantly improves the atom economy and effective conversion rate of the reaction, has mild reaction conditions, produces products without significant racemization, has controllable impurities, and simplifies post-processing and purification. The by-product waste salt can be recycled, making it suitable for large-scale industrial production.

The invention provides a method for detecting enantiomers of thiamphenicol glycine ester hydrochloride or thiamphenicol glycine ester hydrochloride in a preparation thereof. The method comprises the following steps: preparing a test solution: taking thiamphenicol glycine ester hydrochloride or a preparation thereof to prepare a test solution; chromatographic conditions: adopting chiral chromatography with cellulose tris-(4-chloro-3-methylphenylcarbamate) as a stationary phase and n-hexane:methanol:anhydrous ethanol:trifluoroacetic acid:ethanolamine as a mobile phase; and a determination method: taking the test solution and injecting it into a liquid chromatograph for determination.

The application discloses a trifluoromethyl benzyl ether substituted amino acid derivative, a preparation method and application thereof, and belongs to the technical field of organic compound synthesis and medicine. The synthesis method of the trifluoromethyl benzyl ether substituted amino acid derivative is obtained through two-step reaction, that is, first, a photo extension reaction is carried out between a benzyl alcohol compound and hydroxynaphthaldehyde (or hydroxybenzaldehyde), then a Schiff base is formed after an amino acid ester hydrochloride, and then the Schiff base is reduced by sodium cyanoborohydride, and then simple hydrolysis is carried out to obtain the trifluoromethyl benzyl ether substituted amino acid derivative. The preparation method has the characteristics of simple steps, mild reaction conditions and fast reaction, and meets the requirements of green chemistry. The compound prepared according to the method can selectively adjust S1P1 receptors without exciting S1P3 receptors, and is expected to be developed into a new preparation for treating idiopathic pulmonary fibrosis.

The invention provides a high performance liquid chromatography detection method of L-homoserine lactone hydrochloride, which comprises the following steps: diluting a test sample containing L-homoserine lactone hydrochloride with a diluent to obtain an L-homoserine lactone hydrochloride solution, filtering the L-homoserine lactone hydrochloride solution, and detecting the filtered L-homoserine lactone hydrochloride solution in a high performance liquid chromatograph, a CAD detector is adopted as a detector; the chromatographic column is formed by chemically bonding hydrophilic groups on organic mixed silica gel particles; the mobile phase comprises a mobile phase A and a mobile phase B, wherein the mobile phase A is acetonitrile or methanol; and the mobile phase B is an ammonium formate or ammonium acetate aqueous solution. Under the chromatographic conditions, after a base line is stable, samples are sequentially injected according to the sequence of standard sample solutions and test sample solutions with multiple gradient concentrations, standard sample solution map data and test sample map data with multiple gradient concentrations are obtained, then a standard curve of the concentration and the peak area is made, and the content of the L-homoserine test sample is calculated by combining the weighing amount of the L-homoserine test sample.

The invention discloses a synthesis method of (4S, 5R)-3-[2-[[fluorenylmethoxycarbonyl] amino] acetyl]-2, 2, 5-trimethyl-4-oxazolidine carboxylic acid, which comprises the following steps: S1, carrying out amino protection reaction on L-threonine methyl ester hydrochloride to form a compound I; s2, reacting the compound I with Lewis acid and a cyclization reactant to generate a compound II; s3, performing ammonolysis on the compound II to obtain a compound III; s4, carrying out hydrolysis reaction on the compound III and an alkali reagent to obtain a compound IV; and S5, reacting the compound IV with an fmoc protection reagent to obtain a final product (4S, 5R)-3-[2-[[fluorenylmethoxycarbonyl] amino] acetyl]-2, 2, 5-trimethyl-4-oxazolidine carboxylic acid. The method is high in yield and purity and low in cost.

The invention belongs to the technical field of biological medicines, and particularly relates to a preparation method of a high-purity litexitinib tosylate intermediate. The intermediate is N-((3R, 6S)-6-methylpiperidine-3-yl)-7H-pyrrole [2, 3-d] pyrimidine 4-amine, and the preparation method comprises the following steps: reacting (2S, 5R)-5-amino-2-methylpiperidine-1-benzyl formate hydrochloride with 4-chloro-7-Ts-pyrrole [2, 3-D] pyrimidine in the presence of an acid-binding agent under a reflux condition, extracting and concentrating to obtain a primary substitution product, and purifying to obtain the intermediate. And removing benzyl ester (Cbz) protecting groups by using hydrochloric acid, concentrating after extraction, removing Ts by using sodium hydroxide, and carrying out solid-liquid separation, water washing and drying to obtain the target intermediate. The synthesis method provided by the invention has the advantages of less side reaction, high yield, less organic solvent dosage and less three wastes. And the obtained litexitinib tosylate intermediate is high in purity, good in character, small in batch-to-batch difference and stable in quality.

The invention relates to a compound MDMB-BUTINACA-D3 as well as preparation and application thereof, and the structural formula of the compound MDMB-BUTINACA-D3 is as follows: 2-(1H-indazole-3-formamido)-3, 3, 4-triazole-3-carboxylic acid is obtained through condensation reaction of indazole-3-carboxylic acid and tert-leucine methyl ester hydrochloride; the preparation method comprises the following steps: adding 2-(1H-indazole-3-formamido)-3, 3-dimethyl butyric acid methyl ester into 2-(1H-indazole-3-formamido)-3, 3-dimethyl butyric acid methyl ester, adding 3-phenoxybromopropane into a Grignard reagent, carrying out a substitution reaction to obtain butoxybenzene-D4, further adding a brominating agent boron tribromide, carrying out a bromination reaction to obtain bromobutane-D3, and finally carrying out a substitution reaction on 2-(1H-indazole-3-formamido)-3, 3-dimethyl butyric acid methyl ester and bromobutane-D3 again to obtain MDMB-BUTINACA-D3. According to the method, the matrix effect can be well avoided, meanwhile, mass spectrum cross signal overlapping caused by natural isotopes can be avoided, and the mass spectrum quantitative analysis precision can be remarkably improved when the method is used as an internal standard substance for MS quantitative determination.

The present invention discloses a cationic surfactant and its preparation and application. The structure of the cationic surfactant is: #imgabs0# A method for preparing the cationic surfactant comprises: (1) reacting dehydroabietic acid with thionyl chloride under the catalysis of 4-dimethylaminopyridine to obtain dehydroabietic acid chloride; (2) reacting dehydroabietic acid chloride with aminoundecanoic acid methyl ester hydrochloride to obtain compound 1; (3) reacting compound 1 with 3-dimethylaminopropylamine to obtain compound 2; and (4) reacting compound 2 with ethyl bromide to obtain the cationic surfactant. The cationic surfactant provided by the present invention can have high viscoelasticity at a relatively low concentration and has low application cost.

The utility model provides a nitrogen supplementing device for diazaspiro-nonane-tert-butyl formate hydrochloride production, which comprises a base, the upper end of the base is fixedly connected with a supporting block, the middle part of the upper end of the supporting block is an arc-shaped concave surface, a gas cylinder is placed in the arc-shaped concave surface, the lower end of the base is provided with a fixed table, and the fixed table is provided with a gas cylinder. The fixing table comprises a fixing plate, a fixing hole is formed in the fixing plate in a penetrating mode, a guide rod is vertically and fixedly connected to the center of the interior of the base, a locking block of a cylindrical step structure is arranged on the guide rod in a sliding mode, the lower portion of the locking block is matched with the fixing hole, and a spring is arranged on the upper portion of the locking block. And the spring upwards abuts against the inner wall of the base, and the side wall of the upper portion of the locking block is fixedly connected with a shifting rod. According to the gas cylinder supporting device, the gas cylinder supporting stability can be improved, and meanwhile the placement occupied area is reduced.

The present invention discloses a method for preparing D-p-hydroxyphenylglycine methyl ester hydrochloride, and belongs to the field of pharmaceutical chemicals. The method comprises the following steps: adding D-p-hydroxyphenylglycine to methanol, mixing uniformly, adding an acylating agent, reacting, and obtaining D-p-hydroxyphenylglycine methyl ester hydrochloride through post-processing after the reaction. The method of the present invention has low production cost, high yield, short reaction time, simple post-processing operation, environmental friendliness, high product purity, easy transportation and storage, and is suitable for industrial production.

The application provides a medical light guide gel with high light guide performance and a preparation method thereof. The medical light guide gel with high light guide performance comprises pure water, glycerol and carbomer, and further comprises aminolevulinic acid propyl ester hydrochloride. The aminolevulinic acid propyl ester hydrochloride is recrystallized, mixed with other components, stirred for 10-15 min, and then the product is prepared by standing. The technical scheme has the technical characteristics of high light penetration, and improves the treatment efficiency and the phototherapy effect.

The invention provides comeflufen hydrochloride as well as a crystal form, a preparation method and application thereof. The comeflufen hydrochloride disclosed by the invention is 3-(3-ethyl-1-methyl-1H-hexahydroazepine-3-yl) and 2-(2-fluoro-4-biphenyl)-phenyl propionate hydrochloride, has good solubility and stability, is quick in drug effect, and can avoid the first-pass effect of the liver, improve the bioavailability and achieve the effects of reducing toxicity and enhancing efficiency; the preparation method of the comeflufen hydrochloride is simple, and the product yield is high.

The application provides a refining method of a sacubitril valsartan sodium intermediate, and relates to the field of drug intermediate synthesis. The sacubitril valsartan sodium intermediate compound is (2R, 4S)-4-amino-5-(diphenyl-4-yl)-2-methylvalerate ethyl ester hydrochloride. The application also relates to a control method of specific impurities in the refining process of the compound, which comprises the following steps: mixing the sacubitril valsartan sodium intermediate crude product with ethyl acetate or isopropyl acetate, then heating to a reflux state, keeping the reflux state for 1-2 hours, and then performing slow cooling, pressure filtration, vacuum drying and other process procedures to obtain the sacubitril valsartan sodium intermediate (2R, 4S)-4-amino-5-(diphenyl-4-yl)-2-methylvalerate ethyl ester hydrochloride. The sacubitril valsartan sodium intermediate obtained by the refining method has high purity, no solvent residue, mild reaction conditions and is easy to be industrialized.

The invention belongs to the technical field of chemical engineering, and discloses a synthesis method and application of (2R, 4S)-4-hydroxypyrrolidine-2-carboxylic acid methyl ester hydrochloride, according to the method, trichloroisocyanuric acid is used as an oxidizing agent, silica gel supported 2, 2, 6, 6-tetramethylpiperidine oxide is added as a novel supported catalyst, the supported catalyst is removed and recycled through filtration, and the (2R, 4S)-4-hydroxypyrrolidine-2-carboxylic acid methyl ester hydrochloride is obtained. An oxidation product IM1 is obtained; carrying out trans-chiral reduction on ketone carbonyl by using sodium triacetoxyborohydride as a reducing agent to obtain a trans-amino acid product IM2 which cannot be obtained by a fermentation method; finally, the target product-(2R, 4S)-4-hydroxypyrrolidine-2-carboxylic acid methyl ester hydrochloride is synthesized in one step through thionyl chloride under the heating reaction condition in a methanol system. The product prepared by the method is relatively high in purity, low in raw material cost, simple to operate and suitable for industrial production, and can meet the requirements in the fields of medicines and the like in the future.

The invention relates to the technical field of polypeptide drugs, and particularly discloses a synthetic method of pseudo-proline dipeptide. The method comprises the following steps: by taking amino-protected Fmoc-Xaa-OH and serine methyl ester hydrochloride or threonine methyl ester hydrochloride as raw materials, firstly carrying out amino acid condensation, then carrying out acid catalysis with 2, 2-dimethoxypropane to obtain a cyclized intermediate, and finally hydrolyzing in the presence of an organic tin alkali reagent to generate the target compound pseudo-proline dipeptide. The method has the advantages of mild conditions, high selectivity, high conversion rate, few by-products, almost complete avoidance of racemization, perfect reservation of the acid-sensitive oxazolidine ring, no influence on other common protecting groups such as Fmoc, Boc and Trt, high selectivity, no influence on other more stable esters such as tert-butyl ester and benzyl ester, and good substrate adaptability.