High-yield vildagliptin preparation process based on solid-phase synthesis

Abstract

The invention relates to the technical field of vildagliptin production, in particular to a high-yield vildagliptin preparation process based on solid-phase synthesis, by introducing an alkyl chain for alkylation reaction and a click chemistry method, the synthesis path is greatly simplified, the complex operation required by multi-step liquid-phase synthesis is reduced, and the overall synthesis efficiency is improved. Click chemistry is used as an efficient and high-selectivity reaction type, functional groups can be rapidly introduced under mild conditions, and the occurrence probability of side reactions is remarkably reduced, so that the yield of a target compound is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of vildagliptin production, and in particular to a high-yield preparation process of vildagliptin based on solid phase synthesis. Background Art

[0002] Currently, vildagliptin is an important dipeptidyl peptidase-4 (DPP-4) inhibitor used to treat type 2 diabetes. The traditional synthesis method of vildagliptin usually adopts liquid phase synthesis, which has problems such as cumbersome reaction steps, difficult separation and purification, and low yield. In order to improve the synthesis efficiency and yield of vildagliptin, researchers began to explore new synthesis strategies.

[0003] Solid phase synthesis is a method of connecting a reaction substrate to an insoluble solid support for reaction. This method has the advantages of simple operation, mild reaction conditions, and easy separation of products. However, the application of solid phase synthesis to the preparation of vildagliptin still faces some challenges. First, the selection of a suitable solid phase support is crucial to the reaction efficiency, but there is currently a lack of specialized optimization for the synthesis of vildagliptin. Secondly, the reaction route for constructing the molecular skeleton of vildagliptin on a solid phase support needs to be further optimized to improve the reaction efficiency and yield. In addition, how to effectively cut the target product from the solid phase support and ensure the purity of the product is also a key issue that needs to be solved.

[0004] Existing solid phase synthesis methods for vildagliptin usually adopt conventional peptide synthesis strategies, that is, gradually constructing amino acid sequences on solid phase supports. Although this method is feasible, it is not efficient and is prone to produce by-products. In addition, traditional methods often require harsh reaction conditions when introducing side chains and performing cyclization reactions, which may lead to product degradation or the occurrence of side reactions.

[0005] In this regard, the present invention specifically proposes a high-yield preparation process of vildagliptin based on solid phase synthesis to solve the above technical problems. Summary of the invention

[0006] The present invention provides a high-yield preparation process of vildagliptin based on solid phase synthesis. By introducing an alkyl chain for alkylation reaction and click chemistry, the synthesis path is greatly simplified, the complex operations required for multi-step liquid phase synthesis are reduced, and the overall synthesis efficiency is improved. Reduce the generation of by-products: Click chemistry, as a highly efficient and selective reaction type, can quickly complete the introduction of functional groups under mild conditions, significantly reducing the probability of side reactions, thereby increasing the yield of the target compound.

[0007] The technical solution adopted by the present invention to solve the above technical problems is: a high-yield preparation process of vildagliptin based on solid phase synthesis, comprising the following steps:

[0008] Step a. Selecting a functionalized polymer resin having a specific functional group as a solid phase carrier;

[0009] Step b. covalently linking the D-phenylalanine derivative to the solid phase carrier through a peptide bond formation reaction to form a supported intermediate;

[0010] Step c. introducing an alkyl chain into the supported intermediate for alkylation reaction to obtain a supported intermediate with a new alkyl side chain;

[0011] Step d. using a click chemistry method to react the supported intermediate with a new alkyl side chain to obtain a supported intermediate modified by click chemistry;

[0012] Step e. modifying specific positions of the loaded intermediate modified by click chemistry to complete the construction of the entire molecular framework;

[0013] Step f. After the molecular framework is constructed, the target compound is released from the solid phase carrier by a cleavage reaction at 30°C-40°C, and the target compound is purified by chromatographic separation technology.

[0014] Furthermore, the functional group in step a is any one of amino, carboxyl, hydroxyl or thiol.

[0015] Furthermore, the specific enzyme in step e is any one of formaldehyde dehydrogenase, aldehyde-keto reductase or amine reductase.

[0016] Furthermore, the supported intermediate with a neoalkyl side chain has a terminal alkynyl functional group.

[0017] Furthermore, in step d, the click chemistry method is used to react the supported intermediate with a new alkyl side chain, including:

[0018] Step d1: Select a functional molecule containing an azide group as a click chemistry partner;

[0019] Step d2: water is selected as an organic solvent, copper sulfate pentahydrate is added to the water as a catalyst, and sodium ascorbate is added to stabilize copper ions to form a reaction solvent;

[0020] Step d3: The functional molecule having an azide group is dissolved in a reaction solvent and then mixed thoroughly with the supported intermediate having a new alkyl side chain;

[0021] Step d4: Once all ingredients are prepared and mixed evenly, the reaction begins. During the reaction, the progress of the reaction is monitored by thin layer chromatography or liquid chromatography to ensure complete conversion. After the reaction is completed, mass spectrometry is used to verify the formation of the target product.

[0022] Furthermore, the specific positions of the loaded intermediate modified by click chemistry in step e include the substituents on the pyrrolidone ring, the substituents on the benzene ring and the functional groups at the ends of the side chains.

[0023] Further, the cleavage reaction in step f comprises the following steps:

[0024] Step f1: a mixture of TFA and dichloromethane was used as the cleavage solvent;

[0025] Step f2: transferring the supported intermediate on the solid support into a container;

[0026] Step f3: according to the amount of solid support and the expected yield of the target compound, add lysis solvent to the container, ensure that the solid support is fully in contact with the lysis solvent, and use a magnetic stirrer or a rotary shaker to promote uniform mixing;

[0027] Step f4: Once the cleavage is confirmed to be complete, the reaction is stopped immediately, and the solid phase carrier is removed by filtration, leaving the cleavage solution containing the target compound.

[0028] The advantages of the present invention are:

[0029] The present invention successfully solves the problems of complicated reaction steps, difficult separation and purification, low yield, etc. in the traditional vildagliptin synthesis method by optimizing the solid phase synthesis process, and improves the shortcomings of the existing solid phase synthesis method. The specific technical effects achieved are as follows:

[0030] 1. Improve synthesis efficiency and yield: The present invention greatly simplifies the synthesis path by introducing alkyl chains for alkylation reaction and click chemistry, reduces the complex operations required for multi-step liquid phase synthesis, and improves the overall synthesis efficiency. Reduce the generation of by-products: Click chemistry, as a highly efficient and selective reaction type, can quickly complete the introduction of functional groups under mild conditions, significantly reducing the probability of side reactions, thereby increasing the yield of the target compound.

[0031] 2. Optimize the selection and application of solid phase carriers

[0032] The present invention ensures the smooth progress of the subsequent covalent linking reaction by selecting a functionalized polymer resin with specific functional groups as a solid phase carrier, laying the foundation for efficient molecular construction. The terminal alkynyl functional group is introduced into the supported intermediate, so that the click chemistry reaction can be carried out efficiently, further enhancing the flexibility and controllability of the synthetic route. DETAILED DESCRIPTION

[0033] The technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Embodiment 1:

[0035] The present invention proposes a high-yield preparation process of vildagliptin based on solid phase synthesis, comprising the following steps: selecting a functionalized polymer resin with a specific functional group as a solid phase carrier; covalently connecting a D-phenylalanine derivative to the solid phase carrier through a peptide bond formation reaction to form a loaded intermediate; introducing an alkyl chain into the loaded intermediate for an alkylation reaction to obtain a loaded intermediate with a new alkyl side chain; using a click chemistry method to react the loaded intermediate with a new alkyl side chain to obtain a loaded intermediate modified by click chemistry; modifying a specific position of the loaded intermediate modified by click chemistry to complete the construction of the entire molecular framework; after the molecular framework is constructed, the target compound is released from the solid phase carrier through a cleavage reaction under 30°C-40°C, and the target compound is purified by a chromatographic separation technique. In the detailed explanation of the technical features, the selection of the functionalized polymer resin is the key, wherein the functional group can be an amino group, a carboxyl group, a hydroxyl group or a thiol group, which can effectively form a stable peptide bond with the D-phenylalanine derivative. In the alkylation reaction, the introduced alkyl chain can be straight or branched, and the specific length and structure can be adjusted according to the needs of the target compound. In the click chemistry method, the functional molecule used contains an azide group, which can undergo an efficient click reaction with a supported intermediate with a terminal alkynyl functional group to form a stable triazole ring structure. In the cleavage reaction, the TFA and dichloromethane mixture used can effectively release the target compound from the solid phase support while maintaining the structural integrity of the compound.

[0036] The technical solution of the present invention realizes the efficient preparation of vildagliptin by a solid phase synthesis method, combined with click chemistry and alkylation reaction. Compared with the prior art, this solution has the advantages of simple operation, mild reaction conditions, high product purity and high yield. Specifically, the use of a solid phase carrier makes the reaction process easy to control and separate, the application of the click chemistry method improves the efficiency and selectivity of the reaction, and the mild cleavage conditions ensure the structural stability and activity of the target compound.

[0037] Further, the present invention also proposes that in step a, the functional group of the functionalized polymer resin is any one of amino, carboxyl, hydroxyl or sulfhydryl functional groups. The selection of these functional groups provides necessary active sites for subsequent chemical reactions, so that the D-phenylalanine derivative can be effectively covalently linked to the solid phase carrier through a peptide bond formation reaction. Specifically, the amino functional group can form an amide bond with the carboxyl group in the D-phenylalanine derivative, the carboxyl functional group can form an amide bond with the amino group in the D-phenylalanine derivative, the hydroxyl functional group can be connected to the carboxyl group in the D-phenylalanine derivative through an esterification reaction, and the sulfhydryl functional group can be connected to the carboxyl group in the D-phenylalanine derivative through a thioesterification reaction. These different functional groups provide a variety of possible connection methods, so that the process has high flexibility and adaptability. As a preferred embodiment, the functional group of the functionalized polymer resin is an amino group. The amino functional group has a high reactivity and can quickly form an amide bond with the carboxyl group in the D-phenylalanine derivative, thereby improving the efficiency and yield of the reaction. In addition, the amino functional group also exhibits good stability in subsequent alkylation reactions and click chemistry reactions, ensuring the smooth progress of the entire process. Thus, the technical solution of the present invention ensures that the D-phenylalanine derivative can be effectively connected to the solid phase carrier by selecting a specific functional group, and provides a stable basis for subsequent chemical reactions. Compared with the prior art, this solution not only improves the efficiency and yield of the reaction, but also enhances the flexibility and adaptability of the process, solving the problem of single functional group selection and low reaction efficiency in the prior art.

[0038] Further, the present invention also proposes that in step e, the specific enzyme is any one of formaldehyde dehydrogenase, aldehyde-keto reductase or amine reductase. The selection of these enzymes is based on their ability to effectively catalyze the modification reaction of a specific position, thereby completing the construction of the entire molecular framework. Specifically, formaldehyde dehydrogenase can catalyze the oxidation reaction of formaldehyde and convert it into formic acid, and this process is used to introduce or modify specific functional groups in the construction of the molecular framework. Aldosterone reductase can catalyze the reduction reaction of aldehydes or ketones and convert them into corresponding alcohols. This step is used to adjust the stereochemical properties of the molecule or increase the stability of the molecule in the construction of the molecular framework. Amine reductase can catalyze the reduction reaction of amines and convert them into corresponding amines. This process is used to introduce or modify specific amine groups in the construction of the molecular framework.

[0039] As a preferred embodiment, formaldehyde dehydrogenase can be used to introduce specific substituents on the pyrrolidone ring, thereby enhancing the biological activity of the molecule. Aldehyde-keto reductase can be used to introduce specific substituents on the benzene ring, thereby adjusting the solubility or stability of the molecule. Amine reductase can be used to introduce specific functional groups at the end of the side chain, thereby enhancing the targeting of the molecule. Thus, the technical scheme of the present invention can effectively complete the construction of the molecular framework by selecting specific enzymes to carry out catalytic reaction, solving the problem of low efficiency and poor selectivity of molecular framework construction in the prior art. Compared with the prior art, the technical scheme of the present invention has higher reaction efficiency and better selectivity, and can significantly improve the yield and purity of vildagliptin.

[0040] Further, the present invention also proposes that the supported intermediate with a new alkyl side chain has a terminal alkynyl functional group. The presence of the terminal alkynyl functional group enables the intermediate to react efficiently and selectively with other functional molecules containing an azide group through a click chemistry reaction. Specifically, the terminal alkynyl functional group can react with the azide group through a copper-catalyzed azide-alkyne cycloaddition reaction (CuAAC) to form a stable triazole ring structure. This reaction has high selectivity, high yield and mild reaction conditions, and is suitable for complex molecular construction in solid phase synthesis. As a preferred embodiment, the terminal alkynyl functional group can be achieved by introducing an alkynylating agent in an alkylation reaction. For example, using an alkynyl bromide or an alkynyl iodide as an alkylating agent, an alkynyl functional group can be introduced at the end of the alkyl chain of the supported intermediate. In addition, the alkynyl functional group can also be introduced by other chemical modification methods, such as reacting the hydroxyl or amino group on the alkynylating agent with the intermediate.

[0041] Thus, the technical solution of the present invention enables the supported intermediate to be further modified and functionalized by click chemistry reaction by introducing a terminal alkynyl functional group. This design not only improves the efficiency and selectivity of the reaction, but also provides more possibilities for subsequent molecular construction. Compared with the prior art, this solution has higher flexibility and controllability in solid phase synthesis, and can effectively solve the problem of selective modification in complex molecular synthesis.

[0042] Furthermore, the present invention also proposes specific steps for reacting a supported intermediate with a new alkyl side chain using a click chemistry method. Specifically, a functional molecule containing an azide group is first selected as a click chemistry partner. Next, water is selected as an organic solvent, copper sulfate pentahydrate is added to the water as a catalyst, and sodium ascorbate is added to stabilize the copper ions to form a reaction solvent. Then, the functional molecule containing an azide group is dissolved in the reaction solvent and fully mixed with the supported intermediate with a new alkyl side chain. Once all the ingredients are prepared and mixed evenly, the reaction begins. During the reaction, the progress of the reaction is monitored by thin layer chromatography or liquid chromatography to ensure that the reaction is completely converted. After the reaction is completed, mass spectrometry is used to verify the generation of the target product. Specifically, the application of the click chemistry method in the present invention achieves efficient modification of the supported intermediate by selecting specific functional molecules and reaction conditions. Among them, the functional molecule of the azide group reacts with the supported intermediate with a new alkyl side chain under copper catalysis to form a stable covalent bond. Furthermore, the progress of the reaction is monitored by thin layer chromatography or liquid chromatography to ensure complete conversion of the reaction, thereby improving the efficiency of the reaction and the purity of the product.

[0043] Thus, the technical solution of the present invention solves the problems of low reaction efficiency and low product purity in the prior art by optimizing the steps and conditions of the click chemistry reaction. Specifically, by selecting water as a solvent and adding copper sulfate pentahydrate and sodium ascorbate, not only the stability of the reaction is improved, but also the reaction cost is reduced. In addition, the progress of the reaction is monitored by thin layer chromatography or liquid chromatography to ensure the complete conversion of the reaction, thereby improving the purity and yield of the product. Compared with the prior art, the technical solution of the present invention has higher reaction efficiency and better product quality.

[0044] Furthermore, the present invention also proposes that the specific positions of the loaded intermediate modified by click chemistry include the substituents on the pyrrolidone ring, the substituents on the benzene ring and the functional groups at the end of the side chain. The modification of these specific positions is to complete the construction of the entire molecular framework and ensure the structural integrity and functionality of the target compound.

[0045] Specifically, the substituents on the pyrrolidone ring can adjust the electronic properties and spatial configuration of the molecule by introducing different chemical groups, thereby affecting its biological activity. The substituents on the benzene ring can adjust the lipophilicity and solubility of the molecule by introducing different functional groups, thereby affecting its pharmacokinetic properties. The functional groups at the end of the side chain can be further functionalized by introducing specific chemical groups to achieve the molecule, such as introducing fluorescent markers or targeting groups. As a preferred embodiment, the substituents on the pyrrolidone ring can be groups such as halogen, alkyl, alkoxy or amino. The substituents on the benzene ring can be groups such as halogen, nitro, cyano or carboxyl. The functional groups at the end of the side chain can be groups such as alkynyl, azido or carboxyl. The selection of these groups can be adjusted according to the specific needs of the target compound to achieve optimal chemical and biological properties. Thus, the technical solution of the present invention can effectively construct a vildagliptin molecule with a specific structure and function by accurately controlling the modification of a specific position of the load-type intermediate. Compared with existing technologies, this approach has higher flexibility and controllability, and can precisely modify and functionalize molecules according to actual needs, thereby significantly improving the yield and purity of the target compound.

[0046] Further, the present invention also proposes that the cleavage reaction comprises the following steps: a mixture of TFA and dichloromethane is used as a cleavage solvent; the loaded intermediate on the solid phase carrier is transferred to a container; according to the amount of the solid phase carrier and the expected yield of the target compound, a cleavage solvent is added to the container to ensure that the solid support is fully in contact with the cleavage solvent, and a magnetic stirrer or a rotary shaker is used to promote uniform mixing; once the cleavage is confirmed to be complete, the reaction is stopped immediately, the solid phase carrier is removed by filtration, and the cleavage solution containing the target compound is left. Specifically, the choice of cleavage solvent is the key, and a mixture of TFA (trifluoroacetic acid) and dichloromethane can effectively release the target compound from the solid phase carrier. TFA has a strong acidity and can destroy the chemical bond between the solid phase carrier and the target compound, while dichloromethane is used as a solvent to help dissolve and disperse the reactants. During the cleavage process, the loaded intermediate on the solid phase carrier is transferred to a container, and the amount of the cleavage solvent added needs to be accurately controlled according to the amount of the solid phase carrier and the expected yield of the target compound to ensure the efficient conduct of the cleavage reaction. The use of a magnetic stirrer or a rotary shaker helps the cleavage solvent to fully contact the solid phase carrier, thereby promoting the uniformity of the reaction. After the cleavage is completed, the solid phase carrier is removed by filtration, leaving the cleavage solution containing the target compound, which is convenient for the subsequent purification step.

[0047] As a preferred embodiment, the cleavage reaction can be carried out at 30°C-40°C, which can ensure the efficiency of the cleavage reaction and avoid degradation of the target compound at high temperature. In addition, the addition rate of the cleavage solvent can be gradually increased to avoid excessively violent reactions and loss of the target compound.

[0048] Thus, the technical solution of the present invention can effectively release the target compound from the solid phase carrier and ensure the high purity and high yield of the target compound by optimizing the steps and conditions of the cleavage reaction. Compared with the prior art, the technical solution of the present invention has significant advantages in the efficiency of the cleavage reaction and the purification effect of the target compound, and can better meet the needs of actual production.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some or all of the technical features therein can be replaced by equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-yield preparation process of vildagliptin based on solid phase synthesis, characterized in that: The following steps are involved: Step a. Selecting a functionalized polymer resin having a specific functional group as a solid phase carrier; Step b. covalently linking the D-phenylalanine derivative to the solid phase carrier through a peptide bond formation reaction to form a supported intermediate; Step c. introducing an alkyl chain into the supported intermediate for alkylation reaction to obtain a supported intermediate with a new alkyl side chain; Step d. using a click chemistry method to react the supported intermediate with a new alkyl side chain to obtain a supported intermediate modified by click chemistry; Step e. modifying specific positions of the loaded intermediate modified by click chemistry to complete the construction of the entire molecular framework; Step f. After the molecular framework is constructed, the target compound is released from the solid phase carrier by a cleavage reaction at 30°C-40°C, and the target compound is purified by chromatographic separation technology.

2. A high-yield preparation process of vildagliptin based on solid phase synthesis according to claim 1, characterized in that: The functional group in step a is any one of amino, carboxyl, hydroxyl or thiol.

3. A high-yield preparation process of vildagliptin based on solid phase synthesis according to claim 1, characterized in that: The specific enzyme in step e is any one of formaldehyde dehydrogenase, aldehyde-keto reductase or amine reductase.

4. A high-yield preparation process of vildagliptin based on solid phase synthesis according to claim 1, characterized in that: The supported intermediate with a neoalkyl side chain has a terminal alkynyl functionality.

5. A high-yield preparation process of vildagliptin based on solid phase synthesis according to claim 1, characterized in that: The step d in which the supported intermediate with a new alkyl side chain is reacted using a click chemistry method comprises: Step d1: Select a functional molecule containing an azide group as a click chemistry partner; Step d2: water is selected as an organic solvent, copper sulfate pentahydrate is added to the water as a catalyst, and sodium ascorbate is added to stabilize copper ions to form a reaction solvent; Step d3: The functional molecule having an azide group is dissolved in a reaction solvent and then mixed thoroughly with the supported intermediate having a new alkyl side chain; Step d4: Once all ingredients are prepared and mixed evenly, the reaction begins. During the reaction, the progress of the reaction is monitored by thin layer chromatography or liquid chromatography to ensure complete conversion. After the reaction is completed, mass spectrometry is used to verify the formation of the target product.

6. A high-yield preparation process of vildagliptin based on solid phase synthesis according to claim 1, characterized in that: The specific positions of the loaded intermediate modified by click chemistry in step e include the substituents on the pyrrolidone ring, the substituents on the benzene ring and the functional groups at the ends of the side chains.

7. A high-yield preparation process of vildagliptin based on solid phase synthesis according to claim 1, characterized in that: The cleavage reaction in step f comprises the following steps: Step f1: a mixture of TFA and dichloromethane was used as the cleavage solvent; Step f2: transferring the supported intermediate on the solid support into a container; Step f3: according to the amount of solid support and the expected yield of the target compound, add lysis solvent to the container, ensure that the solid support is fully in contact with the lysis solvent, and use a magnetic stirrer or a rotary shaker to promote uniform mixing; Step f4: Once the cleavage is confirmed to be complete, the reaction is stopped immediately, and the solid phase carrier is removed by filtration, leaving the cleavage solution containing the target compound.