Method for synthesizing beta-C-glycosyl amino acid through one-pot method and application of beta-C-glycosyl amino acid in pharmacy
The method of synthesizing β-C-glycosyl amino acids by one pot method, using Pd(acac)2 catalyst and DPPB ligand to synthesize β-C-glycosyl amino acids at room temperature, solving the problem of difficulty in efficiently constructing β-C-glycosyl amino acids in the prior art, and achieving efficient and low-cost synthesis and good stereoselectivity.
Patent Information
- Application Number
- CN202510264209.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-06
- Publication Date
- 2025-07-04
AI Technical Summary
The prior art is difficult to efficiently construct β-C-glycosyl amino acids, especially for stereoselective synthesis under mild conditions, and the multi-step reaction is cumbersome and the cost is high.
The method of synthesizing β-C-glycosyl amino acids was used by one pot method, using Pd(acac)2 as the catalyst and DPPB as the organic phosphine ligand, 3,4-O-carbonate enesugar donor, nitro ester and solvent were added to the N2 atmosphere, and the reaction was carried out at room temperature, reducing by zinc powder and hydrochloric acid, and purified by subsequent column chromatography.
The efficient synthesis of β-C-glycosyl amino acids under mild conditions is achieved, which improves production efficiency and reduces costs, and the synthetic products have good stability and stereoselectivity.
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Abstract
Description
Technical Field
[0001] The present invention provides a method for synthesizing β- C -glycyl amino acids by one-pot reaction using nitroesters as acceptors and its application in pharmaceuticals, belonging to the technical field of organic synthesis. Background Art
[0002] Carbohydrate compounds not only serve as an energy source for human life activities, but also play very important roles in numerous physiological and pathological activities. For example: O -glycoside compound ginsenoside CK has pharmacological effects of inhibiting tumor cell growth and inducing cancer cell apoptosis. N -glycoside compound brivudine has antiviral activity. Compared with O - or N -glycosides, C -glycosides exhibit stronger in vitro and in vivo stability. C -glycosides have become powerful alternatives to natural O / N -glycosylation products, such as the development of a series of SGLT2 inhibitors for type II diabetes (such as dapagliflozin, canagliflozin, and empagliflozin). In addition to aryl C-glycosides, alkyl C-glycosides also widely exist in drugs. For example, the C-glycoside analogs of KRN7000 and blood group H antigen are metabolically stable in vivo and simultaneously exhibit the required biological activities. In addition C -glycyl amino acids or their derivatives are also components of natural products and have significant antifungal activities such as lincomycin and avilamycin. However, compared with the well-studied O / N -glycosylation of amino acids or peptides, the stereoselective C -glycosylation of amino acids or peptides is much more difficult and lacks sufficient methods. Therefore, it is particularly important to construct C-C glycosidic bonds to synthesize glycyl amino acids / glycopeptides, which are molecules of important biological significance.
[0003] With the in-depth research of scientists, more and more effective C -glycyl amino acid / glycopeptide synthesis strategies have been developed. Such as synthesis through transition metal catalysis, radical reactions, C-H activation and other pathways. For example, in 2020, the Niu research group reported a relatively stable radical precursor and synthesized glycyl amino acids and glycopeptides with excellent α selectivity. The above methods mainly obtain α-configured C -glycyl amino acids or α, β mixed glycosylation products. There are still few systems for the stereoselective synthesis of β-configured glycyl amino acids. Most reactions need to be operated under anhydrous and anaerobic conditions, and require multiple steps and harsh conditions such as low temperature and high temperature. Therefore, CThe stereoselective construction of glycosyl amino acids remains a challenging task. SUMMARY OF THE INVENTION
[0004] In view of the above technical problems, the present invention provides a simple and efficient synthetic method for constructing β-C-glycosyl amino acid compounds, comprising the following steps: Under a nitrogen atmosphere, 3,4- O -cyclic carbonate enose donor, palladium catalyst, and organic phosphine ligand are added to a reaction flask for mixing. Then, nitroester and solvent are added, and the mixture is stirred at room temperature. The reaction progress is monitored by TLC. When the nitroester raw material completely disappears, the solvent is removed under vacuum, and zinc powder, THF, and hydrochloric acid are added. The reaction is carried out at room temperature, and the reaction is monitored by TLC. When the glycosylation reaction product is completely consumed, the reaction is terminated. The organic phase is extracted and collected, and the solvent is removed by distillation under reduced pressure to obtain a crude product. Then, column chromatography is carried out using a petroleum ether / ethyl acetate solution as the mobile phase to obtain 4-hydroxy-2,3-unsaturated C-glyco amino acid. The reaction formula is as follows:
[0005] The catalyst includes any one of PdCl2, Pd(OAc)2, and Pd(acac)2.
[0006] The organic ligand includes any one of Xantphos, DPPB, and DPPE.
[0007] The solvent includes any one of acetonitrile, DCM, toluene, THF, and DMSO.
[0008] The 3,4- O -cyclic carbonate enose donor includes: 3,4- O -cyclic carbonate galactoenose donor carrying different 6-position protecting groups of ethers, benzyl protection - Bn; silyl ethers, TBDPS protection of hydroxyl groups, or TBS protection of hydroxyl groups, 3,4- O -cyclic carbonate fucosenose, arabinosenose, any one of them.
[0009] In the sugar receptor nitroester, the structural formula of R 1 is alkyl, benzene ring, and substituted benzene ring. The alkyl includes methyl, ethyl, and isopropyl. The substituents of the substituted benzene ring include 4-chloro substituent, 4-bromo substituent, and 4-trifluoromethyl substituent. The structural formula of R 2 is any one of methyl, ethyl, isopropyl, n-butyl, cyclohexyl, benzyl, and phenyl. The molar ratio of the 3,4- O -cyclic carbonate enose, catalyst, organic ligand, and sugar receptor is 1.5:0.01 - 0.05:0.1 - 0.5:1.0 - 3.0.
[0010] In a preferred embodiment, the molar ratio of the 3,4-cyclocarbonate glycan, catalyst, organic ligand and sugar acceptor is 1.5:0.05:0.1:1.0.
[0011] The conditions of the present invention are mild, the reaction can occur at room temperature, and the reaction has high stereoselectivity. In addition, the successful one-pot reaction shortens the reaction processing steps, which can greatly improve production efficiency and save production costs. Finally, the synthesized C -Glycosyl amino acids have good stability and are of great value in drug synthesis. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 This is the H NMR spectrum of compound 3a.
[0013] Figure 2 This is the C NMR spectrum of compound 3a. DETAILED DESCRIPTION
[0014] Experimental reagents Palladium acetylacetonate (Beijing Bailingwei Technology Co., Ltd.), petroleum ether (boiling range 60-90 °C, Tianjin Hengxing Chemical Reagent Manufacturing Co., Ltd.), ethyl acetate (analytical grade, Tianjin Komiou Chemical Reagent Co., Ltd.), anhydrous sodium sulfate (analytical grade, Sinopharm Chemical Reagent Co., Ltd.), deuterated chloroform (deuterium atomic content 99.8%, TMS content 0.03% V / V, 10*0.5 mL / box, Switzerland ARMAR Company); nuclear magnetic resonance tube (5mm 100 / pk 2 ST500-8, American Norell Company).
[0015] Experimental Instruments ZXZ-4 Rotary Vane Vacuum Pump (Taishi Vacuum Equipment Co., Ltd., Linhai City), DZF-6020 Vacuum Drying Oven (Shanghai Xinmiao Medical Instrument Manufacturing Co., Ltd.), SHB-IIIA Recirculating Water Multi-Purpose Vacuum Pump (Shanghai Yukang Scientific and Educational Instrument Equipment Co., Ltd.), CL-4 Flat Magnetic Stirrer (Zhengzhou Great Wall Science and Industry Co., Ltd.), EYELA SB-1100 Rotary Evaporator (Shanghai Ailang Instrument Co., Ltd.), FA2104B Analytical Balance (Shanghai Yueping Scientific Instrument Co., Ltd.), XRC-1 Micro Melting Point Determinator (Scientific Instrument Factory of Sichuan University), DF-101S Thermostatic Heating Magnetic Stirrer with Heat Collection (Yuhua Instrument Factory, Yingyu, Gongyi City), GZX-9240MBE Digital Display Forced Air Drying Oven (Medical Equipment Factory of Shanghai Boxun Industry Co., Ltd.), ZF-6 Three-Purpose Ultraviolet Analyzer (Shanghai Jiapeng Technology Co., Ltd.), Ultrashied 400 MHz Plus Nuclear Magnetic Resonance Spectrometer (Bruker, Switzerland), API 4000 LC-MS / MS Mass Spectrometer (Bruker Daltonics, Germany) Example 1 Add 6- O -TBDPS-3,4- O -galactal carbonate (0.15 mmol), palladium acetylacetonate (Pd(acac)2, 1.5 mg, 0.005 mmol), 1,4-bis(diphenylphosphino)butane (DPPB, 4.2 mg, 0.01 mmol) into a 5 mL Schlenk tube, evacuate with an oil pump for 20 min, then add the sugar acceptor (isopropyl 2-nitro-3-methylbutyrate) (0.1 mmol) with a microsyringe under N2 protection, and immediately add 2 mL of redistilled DCM. The whole experiment is carried out under anhydrous and anaerobic conditions. Stir at room temperature and monitor the reaction progress by TLC. After the raw material of the enose is completely disappeared, remove the solvent under vacuum, add zinc powder, THF and hydrochloric acid (1 M), and react at room temperature. Monitor the reaction by TLC. When the glycosylation reaction product is completely consumed, terminate the reaction, extract and collect the organic phase, remove the solvent by vacuum distillation to obtain the crude product, and then perform column chromatography using petroleum ether / ethyl acetate solution as the mobile phase to obtain 6-O-TBDPS-4-hydroxy-2,3-unsaturated C-glyco amino acid (yield: 64%).
[0016] For the above process, taking the reaction of 3,4- O -galactal carbonate and isopropyl 2-nitro-3-methylbutyrate as an example, the catalyst, ligand and solvent were adjusted and optimized, and the condition screening is shown in Table 1:
[0017] Note: All experiments were carried out with 0.15 mmol of carbonate galactoenose, 0.1 mmol of isopropyl 2-nitro-3-methylbutyrate, 5 mol% of P catalyst, 10 mol% of phosphine ligand, and 0.15 mmol of base in 2 mL of solvent under stirring at room temperature under anhydrous and anaerobic conditions; the isolated yield; the stereoselectivity was measured by 1H NMR.
[0018] The reaction condition screening experiments showed that when 3,4- O -carbonate galactoenose (1a) was used as the glycosyl donor and isopropyl 2-nitro-3-methylbutyrate was used as the acceptor for condition screening (Table 1). First, Pd2(dba)3 was selected as the catalyst, DPPB as the ligand, and DCM as the solvent to verify my hypothesis. Fortunately, the reaction proceeded smoothly and the nitro group was reduced by zinc powder and hydrochloric acid to synthesize glycosyl amino acid (3c) in one pot with a 21% yield and an isomer ratio of 7.8:1 (Entry 1). Then, some other palladium catalysts were screened, including PdCl2, Pd(OAc)2, Pd(acac)2, and Pd(acac)2 was selected as the best catalyst (Entries 2-4). To further optimize the study, a series of phosphine ligands such as dppp, dppf, DPEPhos, and XantPhos were explored. Unfortunately, the yield and selectivity did not improve further (Entries 5-8). Subsequently, several solvents were screened (Entries 9-12), indicating that DCM is the best solvent for this reaction (Entry 11).
[0019] Summarizing the experimental results, the optimal reaction conditions for galactose aliphatic C-glycoside were obtained as follows: the reaction effect was the best when Pd(acac)2 was used as the catalyst, DPPB as the ligand, and DCM as the solvent.
[0020] Example 2 The present invention uses 6- O -TBDPS-3,4-O-carbonate galactoenose as the raw material and methyl 2-nitro-3-methylbutyrate as the sugar acceptor to prepare 6-O-TBDPS-4-hydroxy-2,3-unsaturated C-glycosyl valine. The technical route is as follows:
[0021] Take 6- O -TBDPS-3,4- O-Galactal carbonate (0.15 mmol), palladium(II) acetylacetonate (Pd(acac)2, 1.6 mg, 0.005 mmol), 1,4-bis(diphenylphosphino)butane (DPPB, 4.2 mg, 0.01 mmol) were added into a 5 mL Schlenk tube. The tube was evacuated with an oil pump for 20 min, and then the sugar acceptor (methyl 2-nitro-3-methylbutyrate) (0.1 mmol) was added via a microsyringe under N2 protection. Immediately, 2 mL of freshly distilled DCM was added. The whole experiment was carried out under anhydrous and anaerobic conditions. Stir at room temperature and monitor the reaction progress by TLC. After the galactal raw material completely disappeared, the solvent was removed under vacuum. Zinc powder, THF and hydrochloric acid (1 M) were added and the reaction was carried out at room temperature. Monitor the reaction by TLC. When the glycosylation reaction product was completely consumed, the reaction was terminated. The organic phase was extracted and collected, and the solvent was removed by distillation under reduced pressure to obtain the crude product. Then, column chromatography was performed using a petroleum ether / ethyl acetate solution as the mobile phase to obtain 6- O -TBDPS-4-hydroxy-2,3-unsaturated C-glyco amino acid (yield: 54%) The 6- prepared in Example 2 above O -TBDPS-4-hydroxy-2,3-unsaturated C -Glycosyl valine methyl ester 1H NMR and 13C NMR data 1 1H NMR (400 MHz, CDCl3) δ 7.74 – 7.66 (m, 4H), 7.45 – 7.35 (m, 6H), 6.22 (ddd, J J = 10.3, 6.0, 2.3 Hz, 1H), 5.73 (dd, J J = 10.3, 2.0 Hz, 1H), 4.49 (d, J J = 2.0 Hz, 1H), 3.96 – 3.91 (m, 1H), 3.87 (dd, J J = 10.5, 5.9 Hz, 1H), 3.81 (dd, J J = 10.5, 6.2 Hz, 1H), 3.73 – 3.65 (m, 4H), 2.18 (hept, J J = 6.8 Hz, 1H), 1.95 (s, 3H), 1.05 (s, 9H), 0.96 (d, J J = 6.8 Hz, 3H), 0.94 (d, J J = 6.8 Hz, 3H). 13 13C{ 11H NMR (100 MHz, CDCl3) δ 174.5, 135.60, 135.58, 133.53, 133.45, 129.9, 129.7, 129.6, 129.3, 127.7, 127.6, 78.0, 77.5, 67.5, 63.8, 62.1, 51.9, 33.4, 26.8, 19.2, 17.9, 16.9. HRMS (ESI) m / z : calcd for C 28 H 40 NO5Si + (M + H) + 498.2670, found, 498.2678; = -23.801 ( c = 1.0, CHCl3). The following products were also prepared under the reaction conditions:
[0022] Activity evaluation The in vitro inhibitory activity of the enzyme α-glucosidase used in the experiment was detected for the inhibitory activity of multiple compounds against α-glucosidase, and acarbose was used as the positive drug. The reaction solution was prepared by dissolving the samples and the positive drug in DMSO, and the compound concentrations were 90, 30, and 10 μM, respectively.
[0023] The in vitro inhibitory activity of α-glucosidase was detected for the inhibitory activity of multiple compounds against α-glucosidase. The experiment was divided into an enzyme activity group (α-glucosidase solution and buffer solution), an enzyme blank group (buffer solution and sample), a positive group (α-glucosidase solution and positive drug solution), a positive blank group (buffer solution and positive drug solution), a sample group (α-glucosidase solution and sample), and a sample blank group (buffer solution and sample). For the above groups, corresponding studies were carried out.
[0024] First: Accurately weigh 1 - 2 mg of the sample and the positive drug (acarbose), dissolve them separately in dimethyl sulfoxide (DMSO), and then dilute the sample solution to the corresponding concentration with PBS buffer solution (0.1 mol / mL, pH = 6.8); Second: Accurately measure 15 μL of the sample and 45 μL of the α-glucosidase solution (0.3 μL / mL) with a standard pipette and add them to a 96-well plate. Shake and mix for 4 minutes to ensure complete mixing. Then preheat at 37 °C, add 20 μL of the substrate (PNPG) solution, shake and mix evenly, and react at 37 °C for half an hour; Third: Add 100 μL of the Na2CO3 solution to terminate the reaction. Finally, obtain the inhibitory activity of the sample from the measured absorbance OD at 405 nm.
[0025] Table 1 shows the determination results of the compounds.
[0026] Table 1: Determination Results of Compounds 。
Claims
1. Method for synthesizing β- C -glycylamino acid by one-pot method, characterized in that, It includes the following steps: Add a 3,4-O-carbonate glycofuranose donor, a palladium catalyst, and an organic phosphine ligand into a reaction flask for mixing in an N2 atmosphere. Then add a sugar acceptor - nitroester and a solvent, and stir at room temperature. Monitor the reaction progress by TLC. When the nitroester raw material completely disappears, remove the solvent under vacuum, add zinc powder, THF, and hydrochloric acid, and carry out the reaction at room temperature. Monitor the reaction by TLC. When the glycosylation reaction product is completely consumed, terminate the reaction to obtain 4-hydroxy-2,3-unsaturated C -glycoamino acid. The reaction formula is as follows: 。 2. The synthesis method of the β- C -glycoamino acid compounds according to claim 1, characterized in that The palladium catalyst described above includes any one of PdCl2, Pd(OAc)2, Pd(dba)2, and Pd(acac)2.
3. According to claim 1, the β- C -sugar amino acid compound synthesis method is characterized in that The organic phosphine ligand described above includes any one of xantphos, DPPB, and DPPE.
4. According to claim 1, the β- C -sugar amino acid compound synthesis method, characterized in that, The solvent described above includes any one of acetonitrile, DCM, Toluene, THF, and DMSO.
5. According to claim 1, the β- C -sugar amino acid compound synthesis method is characterized in that The 3,4-cyclic carbonate enose donor described above includes any one of: ethers of 3,4-cyclic carbonate galactoenose donors carrying different 6-position protecting groups, benzyl protection - Bn; silyl ethers, TBDPS-protected hydroxyl groups, or TBS-protected hydroxyl groups, 3,4-cyclic carbonate fucosenose, and arabinosenose.
6. The β- C - A method for synthesizing a sugar amino acid compound, characterized in that: In the sugar receptor nitroester, R 1 has a structural formula of alkyl, benzene ring and substituted benzene ring. The alkyl includes methyl, ethyl, isopropyl. The substituents of the substituted benzene ring include o-methyl, 4-chloro substituent, 4-bromo substituent, 4-trifluoromethyl substituent; R 2 has a structural formula of any one of methyl, ethyl, isopropyl, n-butyl, cyclohexyl, benzyl, phenyl.
7. The β- C - A method for synthesizing a sugar amino acid compound, characterized in that: 3,4- O -cyclic carbonate glycals, catalyst, molar ratio of organic ligand, sugar receptor is 1.5:0.01 - 0.05:0.1 - 0.5:1.0 - 3.
0.
8. The synthesis method of the β- C -glycoamino acid compounds according to claim 7, characterized in that 3,4- O -Cyclic carbonate glycals, catalyst, organic ligand, and sugar receptor are in a molar ratio of 1.5:0.05:0.1:1.
0.
9. The β- C -glycoamino acid compound synthesized by the synthesis method according to any one of claims 1-8, characterized in that The compound described above includes any one of the following structural formulas: 。 10. An α-glucosidase inhibitor, characterized in that, Includes the β-C-glycino acid compound described in claim 9.