A rigid-flexible combined symmetrical chiral aromatic polyamide modified silica gel stationary phase, a preparation method and application thereof

Abstract

A rigid-flexible combined symmetrical chiral aromatic polyamide modified silica gel stationary phase takes silica gel as a matrix, and a bonded phase is bonded on the surface. A method for preparing the stationary phase comprises the following steps: dispersing silica gel in HCl to obtain activated silica gel; mixing the activated silica gel, anhydrous toluene, and 3-aminopropyl triethoxysilane to obtain aminosilica gel; mixing 1,3,5-benzene tricarbonyl chloride, L-phenylalanine methyl ester hydrochloride, triethylamine, and anhydrous dichloromethane, and extracting an organic phase to obtain an esterification product; dissolving the esterification product and lithium hydroxide monohydrate in tetrahydrofuran and water to obtain a chiral tricarboxylic acid compound; and mixing the chiral tricarboxylic acid compound, N,N-dimethylformamide, a crosslinking agent, N-methylmorpholine-N-oxide, 3,3-dihydroxybenzidine, and the aminosilica gel, and filtering to obtain the symmetrical chiral aromatic polyamide modified silica gel stationary phase. The stationary phase is used for separating chiral aromatic alcohol medical intermediates, chiral drugs, polar and basic compounds. The stationary phase prepared by the method has wide application and good separation performance.

Description

Technical fields:

[0001] This invention relates to the field of chromatographic stationary phase preparation technology, specifically to the preparation of a rigid-flexible symmetrical chiral aromatic polyamide modified silica stationary phase. Background technology:

[0002] High-performance liquid chromatography (HPLC) is an important separation and analysis method with wide applications in drug development, environmental monitoring, and food safety. The stationary phase, as the core component of HPLC, is crucial in separation technology research. However, traditional single-mode stationary phases, such as reversed-phase chromatography, hydrophilic interaction chromatography, and chiral chromatography, while achieving certain separation effects, still have limitations, such as limited applicability. Therefore, researching and developing more efficient, flexible, selective, and widely applicable multi-mode stationary phases is currently a research hotspot.

[0003] Currently, widely used multi-mode high-performance liquid chromatography (HPLC) can achieve multiple retention mechanisms on a single column, offering significant advantages over traditional single-mode chromatography, such as higher separation efficiency, better selectivity, and wider applicability. However, if the modified functional material is too rigid, the corresponding column will exhibit drawbacks such as limited selectivity and low separation efficiency; conversely, if the modified functional material is too flexible, functional groups on the stationary phase surface will become entangled and covered internally, failing to achieve good separation results and reducing column stability. Therefore, there is an urgent need to design a functional material that combines a rigid-flexible structure with chiral recognition sites and specific functional groups, solving the problems of limited column selectivity, low separation efficiency, and low stability, while also serving as a multifunctional material for chiral separation capabilities and mixed separation modes. Summary of the Invention:

[0004] To address the aforementioned problems, this invention provides a rigid-flexible symmetrical chiral aromatic polyamide-modified silica stationary phase, its preparation method, and its applications. This rigid-flexible symmetrical chiral aromatic polyamide-modified silica stationary phase is a novel multifunctional separation material that can be used not only for the separation of chiral aromatic alcohol pharmaceutical intermediates and chiral drugs, but also for hydrophilic chromatography and ion exchange chromatography modes to achieve the separation of various polar and basic compounds.

[0005] A rigid-flexible symmetrical chiral aromatic polyamide-modified silica stationary phase uses silica as a matrix, and the bonded phase is bonded to the surface of the silica matrix through amide bonds. The structural formula of the rigid-flexible symmetrical chiral aromatic polyamide-modified silica stationary phase is as follows:

[0006]

[0007] The bonded phase includes multiple hydrophilic amide groups, hydroxyl groups, amino groups, benzene rings, and biphenyls with non-planar specific structures.

[0008] Preferably, the rigid-flexible symmetrical chiral aromatic polyamide modified silica stationary phase contains 0.2g of the bonding phase per gram of silica.

[0009] Preferably, the silica gel is spherical silica gel with a particle size of 5-7 μm and a specific surface area of ​​300 m². 2 g -1 .

[0010] A method for preparing a rigid-flexible symmetrical chiral aromatic polyamide-modified silica stationary phase includes the following steps:

[0011] Step 1: Preparation of amino silica gel: Disperse 4-7g of silica gel in 40-80ml of 3M HCl, reflux at 100-140℃ for 7h, wash with ultrapure water until neutral, and dry to obtain activated silica gel; disperse the 4-7g of activated silica gel in 40-80ml of anhydrous toluene, add 5-7ml of 3-aminopropyltriethoxysilane, reflux and stir for 24h under N2 atmosphere, filter with a sand core funnel, wash three times each with toluene, ethanol and acetone, and dry in a vacuum drying oven at 50℃ for 12h to obtain amino silica gel;

[0012] Step 2: Synthesis of chiral tricarboxylic acid compounds: Under an ice-water bath and nitrogen atmosphere, 20-50 ml of anhydrous dichloromethane solution containing 1-1.5 g of 1,3,5-benzenetricarboxyl chloride was added dropwise to 40-80 ml of anhydrous dichloromethane solution containing 2.5-3 g of L-phenylalanine methyl ester hydrochloride and 3-3.5 ml of triethylamine. The mixture was stirred at 50-80 °C for 12 h to obtain a first mixture. The first mixture was concentrated under reduced pressure, and the concentrated residue was diluted with water. The diluted residue was extracted, washed, and dried after extraction. The dried organic phase was concentrated under reduced pressure to obtain the esterification product. 1.5-3 g of the esterification product and 0.5-7 g of lithium hydroxide monohydrate were dissolved in 15-30 ml of tetrahydrofuran and 5-15 ml of water. The mixture was stirred at 70-90 °C for 12 h. The concentrated residue was diluted with water. The diluted residue was then treated with 2M... After acidification with HCl, the chiral tricarboxylic acid compound was obtained by filtration, washing, and drying.

[0013] Step 3: Synthesis of a symmetrical chiral aromatic polyamide-modified silica stationary phase: 0.45-0.55 g of the chiral tricarboxylic acid compound was dispersed in 40-60 ml of N,N-dimethylformamide, and 0.5-1.5 g of crosslinking agent was added. The mixture was reacted at room temperature for 20 h. Then, 5-15 ml of N-methylmorpholine-N-oxide was added, and the mixture was stirred. 1-2 g of 3,3-dihydroxybenzidine and 4-7 g of amino silica gel prepared in Step 1 were added, and the mixture was stirred at room temperature for 24 h. The stationary phase was obtained by filtration through a sand core funnel. After washing and drying the stationary phase at 50 °C for 12 h, a symmetrical chiral aromatic polyamide-modified silica stationary phase was obtained. Step 3 is a one-pot synthesis. The carboxyl groups in the chiral tricarboxylic acid compound were activated with a crosslinking agent at a mass ratio of 1:1 to form a stable intermediate. At the same time, the intermediate was coupled with 3,3-dihydroxybenzidine and amino silica gel to obtain the symmetrical chiral aromatic polyamide-modified silica stationary phase. The steps are simple and feasible.

[0014] Preferably, the crosslinking agent is 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide in a mass ratio of 1:1.

[0015] Preferably, in step 2, after the first mixture is concentrated under reduced pressure, the residue is diluted with water, the diluted residue is extracted with ethyl acetate, the organic phase is washed sequentially with 2M hydrochloric acid and saturated sodium bicarbonate solution, and the organic phase is dried with anhydrous sodium sulfate; in step 3, the stationary phase is washed sequentially with cyclohexane, water, and ethanol.

[0016] A rigid-flexible symmetrical chiral aromatic polyamide-modified silica gel immobilizer is used for the separation of chiral aromatic alcohol pharmaceutical intermediates, chiral drugs, and polar and basic compounds.

[0017] Preferably, the rigid-flexible symmetrical chiral aromatic polyamide modified silica gel stationary phase exhibits chiral separation capability and a HILIC / IEC mixed mode during the separation process. Specifically, it demonstrates excellent enantioselectivity in separating chiral aromatic alcohol pharmaceutical intermediates and chiral drugs (D,L-phenylethanol, D,L-phenylpropanol, 1-phenyl-1,2-ethylenediol, 4-chloro-α-methylbenzyl alcohol, ofloxacin, and D,L-mandelic acid, etc.); in hydrophilic interaction chromatography mode, it can selectively separate sulfonamide compounds (sulfadimethylpyrimidine, sulfamethazine, sulfacetyl, sulfabenzoyl) and nucleosides and nucleobases (thiourea, thymine, adenosine, adenine, inosine, cytosine, guanosine); and in ion exchange chromatography mode, it can separate aniline compounds (aniline, o-methylaniline, N-methylaniline, p-chloroaniline, p-phenylenediamine, etc.), all with good separation effects, realizing the application of chiral separation capability and mixed separation mode.

[0018] The advantages of this invention are as follows:

[0019] 1. The reaction conditions are mild, and the steps are simple and feasible. The reaction conditions of the stationary phases prepared in this invention are mostly carried out at low temperatures or room temperature, resulting in mild reaction conditions. Furthermore, the synthesis of symmetrical chiral aromatic polyamide materials and the modification of the silica stationary phase are carried out simultaneously using a one-pot synthesis strategy, making the steps simple and feasible.

[0020] 2. Novel and unique structure with rich and diverse functional groups. The stationary phase structure prepared in this invention has both rigidity and flexibility. The rigid aromatic moiety (benzene ring and non-planar specific structure of biphenyl) can provide a stable steric support environment to enhance intermolecular interactions and help improve the spatial selectivity of the stationary phase. The flexible moiety (chiral sites, amide chains, and methylene groups) can increase the spatial adaptability and diversity of the stationary phase, allowing the chiral recognition sites to bind more effectively to chiral molecules of different shapes and sizes, providing better separation effect and selectivity. Furthermore, the stationary phase structure also contains specific functional groups (such as hydroxyl and amino groups), which also help improve the enantioselectivity, polar selectivity, and separation diversity of the stationary phase.

[0021] 3. Flexible and wide application, with superior separation performance. The stationary phase prepared in this invention can not only separate chiral compounds in normal phase chromatography (NPLC); separate polar compounds in hydrophilic interaction chromatography (HILIC); and even separate basic compounds in ion exchange chromatography (IEC), all exhibiting excellent separation effects. Specifically, it can be used as a chiral chromatogram to achieve high enantioselectivity separation of chiral aromatic alcohol pharmaceutical intermediates and chiral drugs (D,L-phenylethanol, D,L-phenylpropanol, 1-phenyl-1,2-ethylenediol, 4-chloro-α-methylbenzyl alcohol, ofloxacin, and D,L-mandelic acid, etc.); in hydrophilic interaction chromatographic mode, it can selectively separate sulfonamide compounds (sulfadimidine, sulfamethazine, sulfacetyl, sulfabenzoyl) and nucleosides and nucleobases (thiourea, thymine, adenosine, adenine, inosine, cytosine, guanosine); in ion exchange chromatographic mode, it can separate aniline compounds (aniline, o-methylaniline, N-methylaniline, p-chloroaniline, p-phenylenediamine, etc.), realizing the application of chiral separation capabilities and mixed separation modes. Attached image description:

[0022] Appendix Figure 1 Infrared characterization of a rigid-flexible symmetrical chiral aromatic polyamide-modified silica stationary phase.

[0023] Appendix Figure 2 Thermogravimetric characterization of a rigid-flexible symmetrical chiral aromatic polyamide-modified silica stationary phase.

[0024] Appendix Figure 3 The chromatogram is for the separation of aniline compounds using Example 1.

[0025] Appendix Figure 4 The chromatograms for the separation of nucleosides and nucleobases are shown in Example 2.

[0026] Appendix Figure 5 The chromatogram for the separation of sulfonamide compounds is shown in Example 3.

[0027] Appendix Figure 6 The chromatogram for the separation of D,L-phenylethanol is shown in Example 4.

[0028] Appendix Figure 7 The chromatogram for the separation of D,L-phenylpropanol is shown in Example 4.

[0029] Appendix Figure 8 The chromatogram for the separation of 1-phenyl-1,2-ethylene glycol is shown in Example 4.

[0030] Appendix Figure 9 The chromatogram for the separation of 4-chloro-α-methylbenzyl alcohol is shown in Example 4.

[0031] Appendix Figure 10 The chromatogram for the separation of ofloxacin is shown in Example 4.

[0032] Appendix Figure 11 The chromatogram for the separation of D,L-mandelic acid is shown in Example 4. Detailed implementation method:

[0033] To make the technical solution of the present invention easier to understand, the preparation method and application of a rigid-flexible symmetrical chiral aromatic polyamide modified silica stationary phase disclosed in the present invention will now be clearly and completely described in conjunction with the embodiments.

[0034] Example 1:

[0035] Step 1: Preparation of amino silica gel: 4g of silica gel was dispersed in 40ml of 3M HCl and refluxed at 100℃ for 7h. After washing with ultrapure water until neutral, the silica gel was dried to obtain activated silica gel. The 4g of activated silica gel was dispersed in 40ml of anhydrous toluene and 5ml of 3-aminopropyltriethoxysilane was added. The mixture was refluxed and stirred for 24h under N2 atmosphere. After filtration with a sand core funnel, the silica gel was washed three times each with toluene, ethanol, and acetone. After drying in a vacuum drying oven at 50℃ for 12h, amino silica gel was obtained.

[0036] Step 2: Synthesis of chiral tricarboxylic acid compound: Under an ice-water bath and nitrogen atmosphere, 20 ml of anhydrous dichloromethane solution containing 1 g of 1,3,5-phenyltricarboxyl chloride was added dropwise to 40 ml of anhydrous dichloromethane solution containing 2.5 g of L-phenylalanine methyl ester hydrochloride and 3 ml of triethylamine. The mixture was stirred at 50 °C for 12 h to obtain a first mixture. The first mixture was concentrated under reduced pressure, and the residue after concentration was diluted with water. The diluted residue was extracted with ethyl acetate. After extraction, the organic phase was washed successively with 2 M hydrochloric acid and saturated sodium bicarbonate solution, and dried with anhydrous sodium sulfate. The dried organic phase was concentrated under reduced pressure to obtain the esterification product. 1.5 g of the esterification product and 0.5 g of lithium hydroxide monohydrate were dissolved in 15 ml of tetrahydrofuran and 5 ml of water. The mixture was stirred at 70 °C for 12 h. The residue after concentration was diluted with water. The diluted residue was acidified with 2 M HCl, filtered, washed, and dried to obtain the chiral tricarboxylic acid compound.

[0037] Step 3: Synthesis of symmetrical chiral aromatic polyamide modified silica gel stationary phase: 0.45 g of the chiral tricarboxylic acid compound was dispersed in 40 ml of N,N-dimethylformamide, and 0.5 g of crosslinking agent was added. The crosslinking agent was 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide in a mass ratio of 1:1. The reaction was carried out at room temperature for 20 h, and 5 ml of N-methylmorpholine-N-oxide was added. The mixture was stirred, and 1 g of 3,3-dihydroxybenzidine and 4 g of amino silica gel prepared in step 1 were added. The mixture was stirred at room temperature for 24 h, and the stationary phase was obtained by filtration through a sand core funnel. The stationary phase was washed successively with cyclohexane, water, and ethanol, and dried at 50 °C for 12 h to obtain the symmetrical chiral aromatic polyamide modified silica gel stationary phase.

[0038] Example 2:

[0039] Step 1: Preparation of aminosilicone: 7g of silica gel was dispersed in 80ml of 3M HCl and refluxed at 140℃ for 7h. After washing with ultrapure water until neutral, the silica gel was dried to obtain activated silica gel. The 7g of activated silica gel was dispersed in 80ml of anhydrous toluene, and 7ml of 3-aminopropyltriethoxysilane was added. The mixture was refluxed and stirred for 24h under N2 atmosphere. After filtration with a sand core funnel, the silica gel was washed three times each with toluene, ethanol, and acetone. After drying in a vacuum drying oven at 50℃ for 12h, aminosilicone was obtained.

[0040] Step 2: Synthesis of chiral tricarboxylic acid compound: Under an ice-water bath and nitrogen atmosphere, 50 ml of anhydrous dichloromethane solution containing 1.5 g of 1,3,5-phenyltricarboxyl chloride was added dropwise to 80 ml of anhydrous dichloromethane solution containing 3 g of L-phenylalanine methyl ester hydrochloride and 3.5 ml of triethylamine. The mixture was stirred at 80 °C for 12 h to obtain a first mixture. The first mixture was concentrated under reduced pressure, and the residue after concentration was diluted with water. The diluted residue was extracted with ethyl acetate. After extraction, the organic phase was washed successively with 2 M hydrochloric acid and saturated sodium bicarbonate solution, and dried with anhydrous sodium sulfate. The dried organic phase was concentrated under reduced pressure to obtain the esterification product. 3 g of the esterification product and 7 g of lithium hydroxide monohydrate were dissolved in 30 ml of tetrahydrofuran and 15 ml of water. The mixture was stirred at 90 °C for 12 h. After concentration under reduced pressure, the residue was diluted with water. The diluted residue was acidified with 2 M HCl, filtered, washed, and dried to obtain the chiral tricarboxylic acid compound.

[0041] Step 3: Synthesis of symmetrical chiral aromatic polyamide modified silica stationary phase: 0.55 g of the chiral tricarboxylic acid compound was dispersed in 60 ml of N,N-dimethylformamide, and 1.5 g of crosslinking agent was added. The crosslinking agent was 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide in a mass ratio of 1:1. The reaction was carried out at room temperature for 20 h, and 15 ml of N-methylmorpholine-N-oxide was added. The mixture was stirred, and 2 g of 3,3-dihydroxybenzidine and 7 g of amino silica gel prepared in step 1 were added. The mixture was stirred at room temperature for 24 h, and the stationary phase was obtained by filtration through a sand core funnel. The stationary phase was washed successively with cyclohexane, water, and ethanol, and dried at 50 °C for 12 h to obtain the symmetrical chiral aromatic polyamide modified silica stationary phase.

[0042] Example 3:

[0043] Step 1: Preparation of aminosilicone: 5g of silica gel was dispersed in 60ml of 3M HCl and refluxed at 120℃ for 7h. After washing with ultrapure water until neutral, the silica gel was dried to obtain activated silica gel. The 5g of activated silica gel was dispersed in 60ml of anhydrous toluene and 6.5ml of 3-aminopropyltriethoxysilane was added. The mixture was refluxed and stirred for 24h under N2 atmosphere. After filtration with a sand core funnel, the silica gel was washed three times each with toluene, ethanol, and acetone. After drying in a vacuum drying oven at 50℃ for 12h, aminosilicone was obtained.

[0044] Step 2: Synthesis of chiral tricarboxylic acid compound: Under an ice-water bath and nitrogen atmosphere, 40 ml of anhydrous dichloromethane solution containing 1.33 g of 1,3,5-benzenetricarboxyl chloride was added dropwise to 60 ml of anhydrous dichloromethane solution containing 2.69 g of L-phenylalanine methyl ester hydrochloride and 3.2 ml of triethylamine. The mixture was stirred at 60 °C for 12 h to obtain a first mixture. The first mixture was concentrated under reduced pressure, and the residue after concentration was diluted with water. The diluted residue was extracted with ethyl acetate. After extraction, the organic phase was washed successively with 2 M hydrochloric acid and saturated sodium bicarbonate solution, and dried with anhydrous sodium sulfate. The dried organic phase was concentrated under reduced pressure to obtain the esterification product. 2 g of the esterification product and 0.61 g of lithium hydroxide monohydrate were dissolved in 20 ml of tetrahydrofuran and 10 ml of water. The mixture was stirred at 80 °C for 12 h. After concentration under reduced pressure, the residue was diluted with water. The diluted residue was acidified with 2 M HCl, filtered, washed, and dried to obtain the chiral tricarboxylic acid compound.

[0045] Step 3: Synthesis of a symmetrical chiral aromatic polyamide-modified silica stationary phase: 0.5 g of the chiral tricarboxylic acid compound was dispersed in 50 ml of N,N-dimethylformamide, and 1 g of crosslinking agent was added. The crosslinking agent was 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide in a mass ratio of 1:1. The reaction was carried out at room temperature for 20 h, and then 10 ml of N-methylmorpholine-N-oxide was added. The mixture was stirred, and then 1.5 g of 3,3-dihydroxybenzidine and 5 g of amino silica gel prepared in step 1 were added. The mixture was stirred at room temperature for 24 h, and the stationary phase was obtained by filtration through a sand core funnel. The stationary phase was washed successively with cyclohexane, water, and ethanol, and then dried at 50 °C for 12 h to obtain a symmetrical chiral aromatic polyamide-modified silica stationary phase with the following structure:

[0046]

[0047] The prepared symmetrical chiral aromatic polyamide-modified silica gel stationary phase material was characterized as follows:

[0048] 1. The chemical structures of the synthesized amino silica gel (NH2-SiO2), symmetrical chiral aromatic polyamide materials (THPs), and symmetrical chiral aromatic polyamide-modified silica gel stationary phase (TPHs@SiO2) were characterized by Fourier transform infrared spectroscopy (FT-IR). (See attached image.) Figure 1 As shown, the FT-IR spectrum of TPHs@SiO2 exhibits characteristic absorption peaks of NH2-SiO2 and THPs. At 798 cm⁻¹... -1 and 1094cm -1 The relatively broad characteristic absorption peak at 3355 cm⁻¹ is due to the stretching vibrations of Si-OH and Si-O-Si in NH₂-SiO₂. -1 and 3281cm -1The characteristic absorption peak at 1664 cm⁻¹ can be attributed to the -OH vibration present in the material. -1 (Amide I band) and 1580cm -1 The two absorption peaks at the (amide II band) are caused by the stretching vibrations of C=O and CN, at 1511 and 1434 cm⁻¹, respectively. -1 The absorption peak is caused by the vibration of the carbon skeleton of the aromatic ring. Fingerprint region 754 cm⁻¹ -1 and 691cm -1 The characteristic absorption peaks also indicate that the material contains a benzene ring structure. This confirms that a symmetrical chiral aromatic polyamide-modified silica stationary phase was successfully prepared simultaneously with the synthesis of TPHs materials.

[0049] 2. The thermal stability of the NH2-SiO2 and TPHs@SiO2 stationary phases was tested by thermogravimetric analysis (TGA) under a nitrogen atmosphere within a temperature range from room temperature to 800℃. (See attached diagram.) Figure 2 As shown, the weight loss of NH2-SiO2 and TPHs@SiO2 from room temperature to 100℃ can be attributed to the evaporation of water adsorbed on the silica gel surface. For NH2-SiO2, the weight loss from 100 to 800℃ is due to the decomposition of 3-aminopropyltriethoxysilane bonded to the silica gel surface. For the TPHs@SiO2 stationary phase, the weight remains almost unchanged from 100 to 150℃, exhibiting good thermal stability. When the temperature reaches above 150℃, the weight loss of TPHs@SiO2 corresponds to the decomposition of the TPHs material bonded to the silica gel surface, and it exhibits a relatively stable state at 700℃. The total weight loss of the TPHs@SiO2 stationary phase is 20.56%, which fully demonstrates the successful preparation of the TPHs@SiO2 stationary phase.

[0050] Furthermore, the successful preparation of the TPHs@SiO2 stationary phase can also be confirmed by the elemental analysis results shown in Table 1. Compared with silica gel, the contents of C, N, and H in aminosilicone are significantly increased, with C, N, and H increasing to 3.40%, 1.66%, and 1.50%, respectively. After modification with TPHs materials, the contents of C, N, and H increase to 11.3%, 2.38%, and 2.11%, respectively. This further indicates that the synthesized TPHs materials were successfully bonded to the surface of aminosilicone via amide condensation reaction.

[0051] Table 1. Elemental analysis of symmetrical chiral aromatic polyamide-modified silica gel stationary phases.

[0052]

[0053] Application Example 1:

[0054] Using the chromatographic column prepared in Example 3, five aniline compounds were separated in ion-exchange chromatography mode. (Appendix) Figure 3 The chromatographic separation results were as follows: 1. Aniline; 2. o-methylaniline; 3. N-methylaniline; 4. p-chloroaniline; 5. p-phenylenediamine. The chromatographic conditions were: acetonitrile: 40 mM ammonium acetate solution (10 / 90, v / v); flow rate: 1.0 ml / min; temperature: 30℃; detection wavelength: 254 nm.

[0055] Application Example 2:

[0056] Using the chromatographic column prepared in Example 3, seven nucleoside and nucleobase compounds were separated in hydrophilic interaction chromatography mode. Figure 4 The chromatographic separation results were as follows: 1. Thiourea; 2. Thymine; 3. Adenosine; 4. Adenine; 5. Inosine; 6. Cytosine; 7. Guanosine. The chromatographic conditions were: acetonitrile:water (80 / 20, v / v); flow rate: 1.0 ml / min; temperature: 30℃; detection wavelength: 260 nm.

[0057] Application Example 3:

[0058] Using the chromatographic column prepared in Example 3, four sulfonamide compounds were separated in hydrophilic interaction chromatographic mode. Figure 5 The chromatographic separation results were as follows: 1. sulfadimethylpyrimidine; 2. sulfamethazine; 3. sulfacetyl; 4. sulfabenzoyl. The chromatographic conditions were: acetonitrile:water (20 / 80, v / v); flow rate: 1.0 ml / min; temperature: 30℃; detection wavelength: 270 nm.

[0059] Application Example 4:

[0060] Using the chromatographic column prepared in Example 3, six chiral compounds were separated in normal phase chromatography mode. Figure 6 , 7 Images 8, 9, 10, and 11 represent the separation results of the chiral compounds: D,L-phenylethanol, D,L-phenylpropanol, 1-phenyl-1,2-ethylenediol, 4-chloro-α-methylbenzyl alcohol, ofloxacin, and D,L-mandelic acid, respectively. (The appendix is ​​not included in the original text.) Figure 6 , 8 Chromatographic conditions for 9 and 11 were: n-hexane: isopropanol (95 / 5, v / v), with... Figure 7 The chromatographic conditions were as follows: n-hexane: isopropanol (80 / 20, v / v), with... Figure 10 The chromatographic conditions were as follows: n-hexane:isopropanol (90 / 10, v / v); flow rate: 1.0 ml / min; temperature: 30℃; detection wavelength: 254 nm.

[0061] As can be seen from Application Examples 1 to 4, the stationary phase prepared by the method designed in this invention has a good separation effect on a variety of compounds.

[0062] It should be noted that for those skilled in the art, several improvements, substitutions, modifications and refinements can be made without departing from the principles and spirit of this invention, and these improvements, substitutions, modifications and refinements should also be considered within the scope of protection of this invention.

Claims

1. The application of a rigid-flexible symmetrical chiral aromatic polyamide-modified silica stationary phase, characterized in that, The rigid-flexible symmetrical chiral aromatic polyamide-modified silica gel stationary phase is used for the separation of chiral drugs, nucleosides, nucleobases, and aniline compounds. The stationary phase uses silica gel as a matrix, and the bonded phase is bonded to the silica gel matrix surface via amide bonds. The structural formula of the rigid-flexible symmetrical chiral aromatic polyamide-modified silica gel stationary phase is as follows: The bonded phase includes multiple hydrophilic amide groups, hydroxyl groups, amino groups, benzene rings, and biphenyl groups.

2. The application of the rigid-flexible combined symmetrical chiral aromatic polyamide modified silica gel stationary phase as described in claim 1, characterized in that, The rigid-flexible symmetrical chiral aromatic polyamide-modified silica stationary phase contains 0.2g of bonded phase per gram of silica. g .

3. The application of the rigid-flexible combined symmetrical chiral aromatic polyamide modified silica stationary phase as described in claim 2, characterized in that, The silica gel is spherical with a particle size of 5-7 mm. μm Specific surface area is 300 m 2 · g -1 .

4. The application of the rigid-flexible combined symmetrical chiral aromatic polyamide modified silica gel stationary phase as described in claim 1, characterized in that, The method for preparing the stationary phase specifically includes the following steps: Step 1: Preparation of amino silica gel: Silica gel is dispersed in 3M HCl, refluxed, washed with water until neutral, and dried to obtain activated silica gel; The activated silica gel is dispersed in anhydrous toluene, 3-aminopropyltriethoxysilane is added, and under N2 atmosphere, it is refluxed and stirred, filtered, washed successively with toluene, ethanol and acetone, and dried to obtain amino silica gel; Step 2: Synthesis of chiral tricarboxylic acid compounds: Under an ice-water bath and nitrogen atmosphere, an anhydrous dichloromethane solution containing 1,3,5-phenyltricarboxyl chloride was added dropwise to an anhydrous dichloromethane solution containing L-phenylalanine methyl ester hydrochloride and triethylamine. The mixture was stirred to obtain a first mixture. The first mixture was concentrated under reduced pressure, and the concentrated residue was diluted with water. The diluted residue was extracted, and the organic phase was washed and dried after extraction. The dried organic phase was concentrated under reduced pressure to obtain an esterification product. The esterification product and lithium hydroxide monohydrate were dissolved in tetrahydrofuran and water, stirred, and the concentrated residue was diluted with water. The diluted residue was acidified with 2M HCl, filtered, washed, and dried to obtain chiral tricarboxylic acid compounds. Step 3: Synthesis of a symmetrical chiral aromatic polyamide-modified silica gel stationary phase: The chiral tricarboxylic acid compound was dispersed in N,N-dimethylformamide, a crosslinking agent was added, and the reaction was carried out at room temperature for 20 minutes. h Add N-methylmorpholine-N-oxide, stir, add 3,3-dihydroxybenzidine and the amino silica gel prepared in step 1, stir, filter to obtain the stationary phase, wash and dry the stationary phase to obtain a symmetrical chiral aromatic polyamide modified silica gel stationary phase.

5. The application of the rigid-flexible combined symmetrical chiral aromatic polyamide modified silica gel stationary phase as described in claim 4, characterized in that, The crosslinking agent is 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide in a mass ratio of 1:

1.

6. The application of the rigid-flexible combined symmetrical chiral aromatic polyamide modified silica stationary phase as described in claim 4, characterized in that, In step 2, after the first mixture is concentrated under reduced pressure, the residue is diluted with water, the diluted residue is extracted with ethyl acetate, the organic phase is washed sequentially with 2M hydrochloric acid and saturated sodium bicarbonate solution, and the organic phase is dried with anhydrous sodium sulfate; in step 3, the stationary phase is washed sequentially with cyclohexane, water and ethanol.

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