A quinazolinone-based chiral cof nanoparticle-coated silica gel stationary phase and a preparation method and application thereof

Abstract

The application discloses a quinazolinone-based chiral COF nanoparticle-coated silica gel stationary phase and a preparation method and application thereof, and belongs to the technical field of covalent organic framework materials. The technical problems to be solved are that the traditional chiral COF stationary phase is prone to agglomeration, has low column efficiency, high column pressure, limited separation performance and poor stability, and the like, and the application provides a new chiral chromatographic stationary phase with clear structure, reliable performance and significant technical progress. The technical solution points are as follows: the quinazolinone-based chiral COF nanoparticle-coated silica gel stationary phase is prepared from raw materials including a quinazolinone diamine chiral precursor with a structural formula of formula (I), 4,4',4''-(1,3,5-triazine-2,4,6-triazyl)triphenyl formaldehyde and silica gel; formula (I).

Description

Technical Field

[0001] This invention relates to the field of covalent organic framework materials technology, specifically to a silica gel stationary phase coated with quinazolinone-based chiral COF nanoparticles, its preparation method, and its application. Background Technology

[0002] Covalent organic frameworks (COFs), as a novel type of crystalline porous polymer, are mainly composed of lightweight elements such as C, H, O, N, and B. Rigid organic structural units are linked together by covalent bonds, resulting in two-dimensional or three-dimensional porous crystalline framework materials with regular, ordered channels. They possess advantages such as high specific surface area, high stability, ordered pore structure, diverse synthesis methods, and ease of functionalization. Compared with traditional porous materials such as activated carbon and zeolites, COFs have a significant advantage in structural precision.

[0003] Introducing chirality into COF materials endows them with enantioselectivity, making them an ideal platform for chiral separation applications in recent years. In high-performance liquid chromatography (HPLC) chiral separation, COFs are commonly used as coated chiral selectors (J. Am. Chem. Soc., 2018, 140: 892.), bonded chiral selectors (J. Chromatogr. A, 2017, 5: 1348.), and as matrices / carriers for chiral stationary phases (Angew. Chem. 2018, 57: 16754.). These novel HPLC chiral stationary phases have shown good separation performance for natural chiral molecules, chiral pesticides, and chiral drugs. However, these separation performances are still generally inferior to those of commercially available HPLC columns coated with cellulose or amylose derivatives.

[0004] Chiral COFs are typically separated as heterogeneous and insoluble microcrystalline powders. Mixing them with a silica matrix and filling them into stainless steel columns often leads to low column efficiency, high column pressure, and poor separation capabilities. To address this issue, Wang Zixing et al. recently successfully prepared a chiral stationary phase using uniform spherical COFs as a matrix and coated with cellulose derivatives. They applied this to HPLC chiral separation, achieving effective separation of chiral compounds such as metalaxyl, triadimefon, and trans-stilbene oxide (J. Chromatogr. A, 2025, 1756:466087). The inventors believe another strategy to solve the above problems is to prepare chiral COFs into highly dispersed nanoparticle sols and uniformly coat them with macroporous silica. However, to date, there have been no reports on the use of such chiral COF nanoparticles coated with silica for HPLC chiral separation.

[0005] Therefore, developing a chiral COF nanoparticle stationary phase uniformly coated with silica gel has significant research and application value.

[0006] Relevant patent documents retrieved: This document, published in China (CN120923707A) on November 11, 2025, discloses a method for constructing novel chiral chromatographic stationary phases by one-pot in-situ encapsulation of alkali-resistant chiral biological molecules using covalent organic frameworks (COFs) under alkaline catalysis under green and mild conditions. The method is applied to chiral separation studies. The various bonding types of COFs involved in this document are composed of a series of organic monomers linked by covalent bonds, exhibiting excellent stability and good crystallinity. To address the problems of poor stability, low loading rate of chiral resolving agents, easy loss of chiral resolving agents, and limited applicability of traditional chiral chromatographic column stationary phase support materials, this paper creatively designs and develops a new type of covalent organic framework material as a novel support material with broad applicability. Through an aqueous-phase alkaline-catalyzed in-situ encapsulation method, alkali-resistant chiral resolving agents (such as proteins, polysaccharides, and cyclodextrins) are efficiently loaded, thus preparing various high-efficiency and durable chiral stationary phases as novel high-performance chromatographic column packing materials for chiral separation in chromatographic methods (such as high-performance liquid chromatography and capillary chromatography). Various chiral stationary phases prepared using this technology exhibit excellent separation efficiency, high stability, and durability, and have been successfully applied to the efficient separation of various chiral substances, such as chiral amino acids and chiral drugs, with a resolution >1.0. This technology significantly improves the applicability and service life of chiral chromatographic columns.

[0007] This document, published in China (CN107362785A) on November 21, 2017, discloses a chiral covalent organic framework-bonded silica stationary phase with glandular linkages and its applications. The stationary phase is prepared by the following method: Under an inert atmosphere, a chiral hydrazide precursor, trimesin, and amination silica gel are mixed uniformly in an organic solvent, then reacted under acetic acid catalysis. The mixture is then filtered, washed, and dried to obtain the chiral covalent organic framework-bonded silica stationary phase. The structure of the chiral hydrazide precursor is as follows: The mass ratio of the amination silica gel to the chiral hydrazide precursor is 2-12:1, and the molar ratio of the chiral hydrazide precursor to trimesonol is 1:0.5-2. The chiral covalent organic framework-bonded silica gel stationary phase provided in this literature has uniform particle size; when applied to high-performance liquid chromatography, it exhibits high column efficiency and moderate column pressure, and demonstrates good separation performance for cis-trans isomers and positional isomers. Furthermore, the chiral covalent organic framework-bonded silica gel stationary phase in this literature has a well-defined structure, a simple preparation method, and good batch reproducibility.

[0008] The prior art represented by the aforementioned documents has at least the following unresolved technical problems or defects: The preparation relies on aqueous alkaline catalysis, which is not suitable for chiral COF frameworks that require high structural stability, thus limiting its application scenarios. Relevant evidence is: Publication No. CN120923707A, which discloses a green and mild aqueous alkaline catalysis system, but does not disclose the technique for preparing quinazolinone-based chiral COF nanoparticles under acidic conditions.

[0009] The stationary phase is mainly composed of an integral encapsulated structure, which has the problems of slow mass transfer, high column pressure, and limited column efficiency improvement, making it difficult to achieve efficient separation of multiple chiral isomers. The relevant evidence is: Publication No. CN120923707A, which discloses an in-situ encapsulated stationary phase, but does not disclose the technical solutions for nanoparticle dispersion coating, reducing column pressure, and improving column efficiency.

[0010] Simply using in-situ encapsulation to load chiral resolving agents cannot achieve uniform and controllable coating of chiral COF nanoparticles on silica gel surfaces, and is prone to problems such as uneven coating, uncontrollable loading, and low utilization of chiral sites. Relevant evidence is: Publication No. CN120923707A, which only describes the in-situ encapsulation of biological chiral resolving agents in aqueous phase under alkaline catalysis, and does not disclose the technical solution for the controllable preparation of nanoscale chiral COF and uniform coating on silica gel. Summary of the Invention

[0011] The purpose of this invention is to provide: A silica gel stationary phase coated with quinazolinone-based chiral COF nanoparticles, and related technologies, to solve the technical problems of existing chiral COF materials, such as easy aggregation, uneven morphology, high column pressure, low column efficiency, poor chiral selectivity, poor preparation reproducibility, insufficient stability, and difficulty in separating some chiral compounds, or a combination thereof.

[0012] Terminology Explanation: Unless otherwise defined, all technical terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which this subject matter pertains. Unless otherwise stated, all patents, patent inventions, and disclosures cited throughout this document are incorporated herein by reference in their entirety. Where multiple definitions exist for terms herein, the definitions provided in this chapter shall prevail.

[0013] It should be understood that the above brief description and the following detailed description are exemplary and for illustrative purposes only, and do not limit the subject matter of the invention in any way. In this invention, the singular is used in conjunction with the plural unless otherwise specifically stated. It should also be noted that, unless otherwise stated, the use of “or” or “or” means “and / or”. Furthermore, the use of the term “comprising” and other forms such as “including,” “containing,” and “contains” are not limiting.

[0014] Definitions of standard chemical terms can be found in the references "Chiral Recognition Materials (2nd Edition)" (by Yuan Liming, Science Press, 2020) and "Chromatography Technology Series - Chromatographic Chiral Separation Technology and Application" (Chemical Industry Press, 2020).

[0015] Unless otherwise stated, conventional methods within the scope of the art, such as X-ray powder diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, etc., shall be used.

[0016] Unless specifically defined herein, the use of all commercially available products herein employs standard techniques. For example, it may be carried out using the manufacturer's instructions for use with the kit, or in accordance with methods known in the art or the description of this invention. The techniques and methods described herein can generally be implemented according to conventional methods well known in the art, based on the descriptions in the various summary and more specific documents cited and discussed in this specification.

[0017] The “range” disclosed in this document takes the form of a lower limit and an upper limit. It can be one or more lower limits and one or more upper limits, respectively. A given range is defined by selecting a lower limit and an upper limit. The selected lower and upper limits define the boundaries of the particular range. All ranges that can be defined in this way are inclusive and composable; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is also expected that ranges of 60-110 and 80-120 are also expected. Furthermore, if the minimum range values ​​are listed as 1 and 2, and if the maximum ranges are listed as 3, 4, and 5, then the following ranges are all expected: 1-2, 1-4, 1-5, 2-3, 2-4, and 2-5.

[0018] In this invention, unless otherwise specified, the numerical range "ab" represents a shortened representation of any combination of real numbers from a to b, where a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" have been listed in this document, and "0-5" is simply a shortened representation of these numerical combinations.

[0019] The term "quinazolinone" as used in this article refers to a class of nitrogen-containing heterocyclic compounds containing a quinazolinone core and a ketone (carbonyl) group on the ring. They typically have a rigid aromatic ring skeleton and specific coordination and recognition properties, and are often used as organic functional units to construct porous materials or chiral recognition sites.

[0020] The term “covalent organic frameworks (COFs)” as used in this article refers to a class of porous organic polymer materials that are formed by the directional connection of lightweight organic building blocks through covalent bonds, have a long-term ordered crystalline structure and permanent pores, and possess high specific surface area, structural designability and pore controllability.

[0021] The term “nanoparticle” as used in this article refers to solid particles that are at least in the range of 1-100 nm on a one-dimensional scale and often exhibit different surface, optical, dispersion or adsorption properties from macroscopic materials due to their size effect.

[0022] The term "coating" as used in this article refers to a process in which functional materials are uniformly attached to the surface of a carrier through physical adsorption, encapsulation, or film formation to form a continuous or semi-continuous coating layer.

[0023] The term "silica stationary phase" as used in this article refers to an inorganic carrier material with porous spherical silica as the matrix, used as the stationary phase in chromatographic separation, which has high mechanical strength, controllable pore size and good chemical stability.

[0024] The term "chiral separation" as used in this article refers to the process of separating a pair of enantiomers that are mirror images of each other and cannot be superimposed, using chiral recognition. This process is commonly used in techniques such as chromatography, extraction, and membrane separation.

[0025] The term "crystalline porous polymer" as used in this article refers to a high molecular weight polymer with distinct crystal diffraction characteristics and a regular pore or cavity structure inside, as opposed to amorphous porous polymers.

[0026] The term "porous crystalline framework materials" as used in this article refers to a class of porous materials that are formed by structural units connected by covalent or coordinate bonds, and have a periodic crystal structure and interconnected channels. These mainly include covalent organic frameworks (COFs) and metal-organic frameworks (MOFs).

[0027] The term "enantiomer selectivity" used in this paper refers to the ability of a chiral recognition system to preferentially bind, adsorb, or retain a particular enantiomer, which is a core indicator for achieving chiral separation.

[0028] The term "coated chiral selector" as used in this article refers to a chiral functional substance that is loaded onto the surface of a carrier through physical coating and is used to specifically recognize enantiomers.

[0029] The term “bonded chiral selector” as used in this article refers to a chiral functional unit that is covalently linked to the surface of a support via chemical bonding and is used to achieve enantioselective recognition.

[0030] The term "chiral stationary phase" as used in this article refers to a stationary phase material in a chromatographic system that has chiral recognition capabilities and can selectively retain different enantiomers.

[0031] The term "amylose derivatives" as used in this article refers to a class of chiral polymers obtained from amylose through chemical modification such as hydroxyl modification, esterification, and carbamate esterification. These polymers are widely used as highly efficient chiral separation materials.

[0032] The term "microcrystalline powder" used in this article refers to a powdery solid formed by the aggregation of a large number of tiny crystal particles. It has crystalline characteristics but the particle size is small, and it usually exhibits a certain degree of crystallinity and dispersibility.

[0033] The terms "metalaxyl, triadimefon, and trans-stilbene oxide" used in this article refer to: typical chiral pesticide compounds and chiral epoxy model compounds, respectively, commonly used to evaluate the enantiomeric resolution performance of chiral separation materials; among them, metalaxyl has CAS number 57837-19-1 and molecular formula C2. 15 H 21 NO4; Triazolone CAS No. 43121-43-3, Molecular Formula C 14 H 16 ClN3O2; trans-stilbene oxide, CAS No. 1439-07-2, molecular formula C 14 H 12 O.

[0034] The term "quinazolinone diamine" as used in this article refers to an organic monomer whose molecular structure contains both a quinazolinone heterocyclic skeleton and two amino groups (-NH2), which can be used as a rigid connecting unit for constructing porous materials such as covalent organic frameworks; a representative compound is 2,6-diamino-5-chloro-4(3H)quinazolinone, CAS number 143745-30-6, molecular formula C8H7ClN4O.

[0035] The term "4,4′,4′′-(1,3,5-triazine-2,4,6-trimethyl)tribenzaldehyde" as used in this article refers to: a C3 symmetrical rigid aromatic aldehyde monomer with a triazine core and three benzaldehyde functional groups, commonly used to construct highly crystalline two- or three-dimensional covalent organic framework materials via Schiff base reactions; CAS number 443922-06-3, molecular formula C 24 H 15 N3O3.

[0036] The term "amino-modified silica gel" as used in this article refers to silica gel materials whose surface has been modified by amino-silanization to introduce amino functional groups, which can be used for further covalent bonding or loading of functional components.

[0037] The term "two-dimensional honeycomb layered structure" used in this article refers to a layered crystal structure formed in a two-dimensional plane, with a honeycomb-like hexagonal periodic grid and layers stacked by π-π stacking or van der Waals forces. It is commonly found in two-dimensional COF materials.

[0038] The term "N,Nˊ-dicyclohexylcarbodiimide" as used in this article refers to: a commonly used dehydration condensation reagent, mainly used to catalyze amidation or esterification reactions between carboxylic acids and amino or hydroxyl groups, abbreviated as DCC; CAS number 538-75-0, molecular formula C2 13 H 22 N2.

[0039] The term "N-Boc-L-proline" as used in this article refers to L-proline with its amino group protected by a tert-butyloxycarbonyl (Boc) group. It is a common chiral building block and chiral modifying agent used to introduce chiral sites; CAS number 15761-39-4, molecular formula C 10 H 17 NO4.

[0040] The term "dimethyl 2-aminoterephthalate" as used in this article refers to an aromatic compound with both an amino group and two ester groups on its benzene ring. It is commonly used as an intermediate in organic synthesis and can participate in reactions such as condensation and cyclization to construct heterocyclic or polymer units; CAS number 5372-81-6, molecular formula C2. 10 H 11 NO4.

[0041] The term "filtration" as used in this article refers to the conventional operation of separating solid and liquid phases in a solid-liquid mixture through a porous medium, so that solid materials are retained and liquid media permeate, and the solid and liquid phases are separated and collected. This includes, but is not limited to, atmospheric pressure filtration, vacuum filtration, pressure filtration, centrifugal filtration, and other methods.

[0042] The term "washing" as used in this article refers to the routine operation of rinsing the filtered solid material with a suitable solvent to remove unreacted raw materials, by-products, soluble impurities and residual solvents adsorbed on its surface, thereby improving the purity of the product. This includes, but is not limited to, rinsing, soaking, and ultrasonic-assisted washing.

[0043] The term "drying" as used in this article refers to the conventional operation of removing residual solvents, moisture, and other volatile components from solid materials under normal or reduced pressure conditions by means of heating, vacuuming, etc., to obtain a dry and stable solid product, including but not limited to methods such as atmospheric pressure drying, vacuum drying, freeze drying, and hot air drying.

[0044] The term "dispersion" as used in this article refers to the conventional operation of applying physical forces to solid or molecular raw materials in a dispersion medium to make them uniformly distributed in the medium in the form of tiny particles or molecules, thereby improving the uniformity of the system. This includes, but is not limited to, methods such as stirring dispersion, high-speed shear dispersion, homogeneous dispersion, and thermal dissolution dispersion.

[0045] In a first aspect, the present invention provides: a chiral precursor of quinazolinone diamine, with the structural formula shown in formula (I): Equation (Ⅰ).

[0046] Secondly, the present invention provides a method for preparing the chiral precursor of the quinazolinone diamine, comprising the steps of: (1) N,Nˊ-dicyclohexylcarbodiimide, N-Boc-L-proline and 2-aminoterephthalate were dispersed in an organic solvent and reacted. After solid-liquid separation and purification, an acidic deprotecting agent was added to obtain an intermediate. (2) The intermediate obtained in step (1) is subjected to hydrazine hydrate reaction and purified to obtain the final product.

[0047] In some specific embodiments, the molar ratio of N,Nˊ-dicyclohexylcarbodiimide, N-Boc-L-proline, and 2-aminoterephthalate in step (1) ranges from 1 to 2:1 to 1.5:1, for example, 1:1:1, 1.1:1.05:1, 1.2:1.1:1, 1.3:1.15:1, 1.4:1.2:1, 1.5:1.25:1, 1.6:1.3:1, 1.7:1.35:1, 1.8:1.4:1, 1.9:1.45:1, 2:1.5:1, or any range derived therefrom; Preferably, the molar ratio of N,Nˊ-dicyclohexylcarbodiimide, N-Boc-L-proline, and 2-aminoterephthalate in step (1) is 1.2:1:1.

[0048] In some specific embodiments, the organic solvent in step (1) is selected from at least one of tetrahydrofuran, dichloromethane, N,N-dimethylformamide, acetonitrile, and ethyl acetate; Preferably, the organic solvent in step (1) is tetrahydrofuran.

[0049] In some specific embodiments, the temperature of the reaction in step (1) is 0-40°C, for example 0°C, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, or any range derived therefrom; Preferably, the temperature of the reaction in step (1) is 20-25°C.

[0050] In some specific implementations, the reaction time in step (1) is 24-72h, for example 24h, 30h, 36h, 42h, 48h, 54h, 60h, 66h, 72h, or any range derived therefrom; Preferably, the reaction time in step (1) is 72 hours.

[0051] In some specific implementations, the solid-liquid separation method in step (1) includes extraction, washing, drying, concentration and filtration; The organic phase extracted is ethyl acetate; The solution used for filtration is at least one of petroleum ether and n-hexane; preferably, it is petroleum ether and n-hexane in a volume ratio of 1:1.

[0052] In some specific embodiments, the acidic deprotecting agent in step (1) includes at least one of trifluoroacetic acid, HCl / 1,4-dioxane solution, HCl / ethyl acetate solution, formic acid, methanesulfonic acid and p-toluenesulfonic acid; Preferably, the acidic deprotecting agent in step (1) is trifluoroacetic acid.

[0053] Preferably, the reaction time for adding the acidic deprotecting agent in step (1) is 0.5-4 h, for example 0.5 h, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, or any range derived therefrom; More preferably, the reaction time for adding the acidic deprotecting agent in step (1) is 2 hours.

[0054] In some specific embodiments, step (1) after adding the acidic deprotection agent further includes a step of adjusting the pH. Preferably, the pH adjustment range is 7-9, for example 7, 7.2, 7.4, 7.6, 7.8, 8, 8.2, 8.4, 8.6, 8.8, 9, or any range derived therefrom.

[0055] Preferably, the pH adjustment is achieved by adding an aqueous solution of an inorganic alkali or an organic alkali; More preferably, the inorganic alkali aqueous solution or organic alkali is at least one of sodium bicarbonate solution, sodium carbonate solution, potassium carbonate solution, sodium hydroxide solution, potassium hydroxide solution, and triethylamine; More preferably, the pH adjustment is achieved by adding a sodium bicarbonate solution.

[0056] In some specific implementations, the reaction environment of the hydrazine hydrate reaction in step (2) is an inert gas protected environment; Preferably, the reaction environment for the hydrazine hydrate reaction in step (2) is under argon protection.

[0057] In some specific embodiments, the solvent for the hydrazine hydrate reaction in step (2) is selected from at least one of methanol, ethanol, isopropanol, n-propanol, tetrahydrofuran, 1,4-dioxane, N,N-dimethylformamide, dimethyl sulfoxide, and acetonitrile. Preferably, the solvent for the hydrazine hydrate reaction in step (2) is methanol.

[0058] In some specific embodiments, the volume concentration of water in the hydrazine hydrate reaction in step (2) is generally in the range of 50%-100%, for example 50%, 60%, 70%, 80%, 85%, 90%, 95%, 98%, 100%, or any range derived therefrom. Preferably, the volume concentration of water in the hydrazine hydrate reaction in step (2) is 98%.

[0059] In some specific embodiments, the temperature of the hydrazine hydrate reaction in step (2) is 60℃-100℃, for example 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, 100℃, or any range derived therefrom; Preferably, the temperature of the hydrazine hydrate reaction in step (2) is 80°C.

[0060] In some specific embodiments, the duration of the hydrazine hydrate reaction in step (2) is 24-72 h, for example 24 h, 30 h, 36 h, 42 h, 48 h, 54 h, 60 h, 66 h, 72 h, or any range derived therefrom; Preferably, the reaction time of hydrazine hydrate in step (2) is 48 hours.

[0061] In some specific implementations, the purification process in step (2) includes filtration, washing, and drying.

[0062] The washing solvent is selected from at least one of water, methanol, ethanol, isopropanol, acetone, ethyl acetate, acetonitrile, and tetrahydrofuran; Preferably, the solvent used for washing is methanol.

[0063] Thirdly, the present invention provides the application of the chiral precursor of the quinazolinone diamine in the preparation of nanoparticles and / or silica gel stationary phases.

[0064] Preferably, the nanoparticles are: quinazolinone-based chiral covalent organic framework (COF) nanoparticles; Preferably, the silica stationary phase is a silica stationary phase coated with quinazolinone-based chiral COF nanoparticles.

[0065] Fourthly, the present invention provides: a silica gel stationary phase coated with quinazolinone-based chiral COF nanoparticles, the raw materials comprising: a chiral precursor of quinazolinone diamine having the structure shown in formula (I), 4,4′,4′′-(1,3,5-triazine-2,4,6-triyl)tribenzaldehyde, and silica gel.

[0066] Preferably, the silicone is ammoniated silicone; More preferably, the silicone is spherical ammoniated silicone; More preferably, the average pore size of the silicone is ≥100 nm.

[0067] In some specific embodiments, the molar ratio of the quinazolinone diamine chiral precursor to 4,4′,4′′-(1,3,5-triazine-2,4,6-triyl)tribenzaldehyde is 1:0.5-4, for example 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, or any range derived thereof; Preferably, the molar ratio of the chiral precursor of quinazolinone diamine to 4,4′,4′′-(1,3,5-triazine-2,4,6-triyl)tribenzaldehyde is 1:1-2.

[0068] Fifthly, the present invention provides a method for preparing the silica gel stationary phase, comprising the steps of: (1) The chiral precursor of the quinazolinone diamine was reacted with 4,4′,4′′-(1,3,5-triazine-2,4,6-triyl)tribenzaldehyde in an organic solvent to obtain chiral COF nanoparticles; (2) The chiral COF nanoparticles obtained in step (1) are dispersed in an organic solvent with silica gel and purified to obtain the final product.

[0069] In some specific embodiments, the organic solvent in step (1) includes at least one of trifluoroacetic acid, 1,4-dioxane, tetrahydrofuran, acetonitrile, N,N-dimethylformamide, dimethyl sulfoxide, ethyl acetate, and dichloromethane; Preferably, the organic solvent in step (1) is a mixed solution of trifluoroacetic acid and water; More preferably, the organic solvent in step (1) is a mixed solution of trifluoroacetic acid and water in a volume ratio of 1:0.1-1.5, such as 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, or any range derived thereof; More preferably, the organic solvent in step (1) is a mixed solution of trifluoroacetic acid and water with a volume ratio of 1:0.3-1.0; Most preferably, the organic solvent in step (1) is a mixed solution of trifluoroacetic acid and water with a volume ratio of 1:0.47.

[0070] In some specific embodiments, the temperature of the reaction in step (1) is 25-80°C, for example 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, or any range derived therefrom; Preferably, the reaction temperature in step (1) is 40°C.

[0071] In some specific implementations, the reaction time in step (1) is 2-7 days, for example 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, or any range derived therefrom; Preferably, the reaction time in step (1) is 3 days.

[0072] In some specific embodiments, the reaction described in step (1) further includes steps of filtration, washing, and drying; The solvent used for washing is selected from at least one of trifluoroacetic acid, water, dilute hydrochloric acid, dilute acetic acid, formic acid, methanol, ethanol, isopropanol, acetone, acetonitrile, and ethyl acetate. Preferably, the solvent used for washing is trifluoroacetic acid, water, and methanol.

[0073] The drying method is vacuum drying; The drying temperature is selected from 40℃ to 140℃, for example, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, 100℃, 105℃, 110℃, 115℃, 120℃, 125℃, 130℃, 135℃, 140℃, or any range derived therefrom; Preferably, the drying temperature is 80°C.

[0074] In some specific embodiments, the mass ratio of the chiral COF nanoparticles to the ammoniated silica gel in step (2) is 1:2-12, for example 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, or any range derived therefrom; Preferably, the mass ratio of the chiral COF nanoparticles to the ammoniated silica gel in step (2) is 1:9.5.

[0075] In some specific embodiments, the organic solvent in step (2) includes at least one of methanol, ethanol, isopropanol, n-propanol, acetonitrile, ethyl acetate, or tetrahydrofuran; Preferably, the organic solvent in step (2) is methanol.

[0076] In some specific implementations, the purification process in step (2) includes filtration and drying.

[0077] In a sixth aspect, the present invention provides the application of the silica gel stationary phase in high-performance liquid chromatography separation.

[0078] In some specific embodiments, the substances separated by high performance liquid chromatography are chiral isomers of 1-(3-methoxyphenyl)ethylamine, 1-(4-methoxyphenyl)ethylamine, or 2-hydroxy-1,2-di(thienyl)ethane-1-one.

[0079] In a seventh aspect, the present invention provides: a high-performance liquid chromatograph containing the silica gel stationary phase.

[0080] Examples 1-2 of this invention at least support the protection scope of "the application of the silica gel stationary phase in high performance liquid chromatography separation".

[0081] "The application of the silica gel stationary phase in high-performance liquid chromatography separation" is explained above and / or the corresponding technical features in Examples 1-2: "The substances separated by high-performance liquid chromatography are chiral isomers of 1-(3-methoxyphenyl)ethylamine, 1-(4-methoxyphenyl)ethylamine, or 2-hydroxy-1,2-di(thienyl)ethane-1-one". Figure 7 The corresponding high-performance liquid chromatograms are shown, where (a), (b), and (c) represent 1-(3-methoxyphenyl)ethylamine, 1-(4-methoxyphenyl)ethylamine, or 2-hydroxy-1,2-di(thienyl)ethane-1-one, respectively, summarized from these. Therefore, those skilled in the art can reasonably infer that "the application of the silica gel stationary phase in high-performance liquid chromatography separation," its subordinate concepts, its essentially equivalent technical means, and technical means that can replace it within the scope of conventional and common knowledge based on the existing technical level, should all fall within the protection scope of this invention.

[0082] The beneficial effects of this invention are as follows: The present invention has at least the following beneficial effects: (1) The quinazolinone-based chiral COF nanoparticles provided by the present invention are coated with silica gel stationary phase and have uniform particle size. When applied to high performance liquid chromatography, they have high column efficiency and moderate column pressure, and have good separation effect on chiral isomers.

[0083] (2) The quinazolinone-based chiral COF nanoparticles of the present invention are coated with silica gel stationary phase, with a well-defined structure, a simple preparation method, and good batch reproducibility.

[0084] (3) Compared with the prior art, the present invention provides a technical solution with a different technical concept, and its technical effect is equivalent to or slightly improved with the prior art. The differences between the technical concept of the present invention and the prior art include, but are not limited to, the selection and design of chiral building blocks, the type of COF material and the type of skeleton, the composite coating method of chiral COF and silica gel carrier, and the preparation path and assembly strategy of chromatographic stationary phase. Attached Figure Description

[0085] Figure 1This is a flowchart illustrating the preparation process of the silica gel stationary phase coated with quinazolinone-based chiral COF nanoparticles provided in Example 2 of the present invention. Figure 2 This is a flowchart illustrating the preparation process of the chiral precursor of quinazolinone diamine provided in Example 1 of the present invention; Figure 3 This is an X-ray powder diffraction pattern of a silica stationary phase coated with quinazolinone-based chiral COF nanoparticles provided in Example 2 of the present invention. In the figure, (a) is the chiral COF nanoparticles without aminated silica, (b) is the silica stationary phase coated with quinazolinone-based chiral COF nanoparticles, and (c) is the aminated silica. Figure 4 This is a Fourier transform infrared spectrum of a silica gel stationary phase coated with quinazolinone-based chiral COF nanoparticles provided in Example 2 of the present invention. In the figure, (a) is a chiral precursor of quinazolinone diamine, (b) is 4,4′,4′′-(1,3,5-triazine-2,4,6-triyl)tribenzaldehyde, (c) is chiral COF nanoparticles, and (d) is a silica gel stationary phase coated with quinazolinone-based chiral COF nanoparticles. Figure 5 This is a scanning electron microscope image of a silica gel stationary phase coated with quinazolinone-based chiral COF nanoparticles provided in Example 2 of the present invention. In the image, (a) is the chiral COF nanoparticles, (b) is the silica gel stationary phase coated with quinazolinone-based chiral COF nanoparticles, and (c) is the ammoniated silica gel.

[0086] Figure 6 The thermogravimetric analysis curve of the silica gel stationary phase coated with quinazolinone-based chiral COF nanoparticles provided in Example 2 of this invention is shown.

[0087] Figure 7 These are high-performance liquid chromatography (HPLC) chromatograms of 1-(3-methoxyphenyl)ethylamine, 1-(4-methoxyphenyl)ethylamine, and 2-hydroxy-1,2-di(thienyl)ethane-1-one on a silica gel stationary phase coated with quinazolinone-based chiral COF nanoparticles provided in Example 2. In the figure, (a) represents the HPLC chromatogram of 1-(3-methoxyphenyl)ethylamine; (b) represents the HPLC chromatogram of 1-(4-methoxyphenyl)ethylamine; and (c) represents the HPLC chromatogram of 2-hydroxy-1,2-di(thienyl)ethane-1-one.

[0088] Figure 8 This is a high-performance liquid chromatography (HPLC) separation diagram of 1-(3-methoxyphenyl)ethylamine on a commercial OD column and a commercial AD column.

[0089] Figure 9 The image shows the 1H NMR spectrum of the chiral precursor of quinazolinone diamine. Detailed Implementation

[0090] The following non-limiting embodiments are intended to enable those skilled in the art to gain a more comprehensive understanding of the present invention, but do not limit the invention in any way. The following content is merely an exemplary description of the scope of protection claimed by the present invention, and those skilled in the art can make various changes and modifications to the present invention based on the disclosed content, and such changes should also fall within the scope of protection claimed by the present invention.

[0091] The present invention will be further described below by way of specific embodiments. Unless otherwise specified, all instruments, devices, equipment, reagents, products, etc., used in the embodiments of the present invention are obtained through conventional commercial means.

[0092] The structure of the synthesized quinazolinone-based chiral COF nanoparticles coated with a silica gel stationary phase can be characterized by X-ray powder diffraction. Within the scope of this invention, chiral COF nanoparticles prepared from quinazolinone diamine chiral precursors and 4,4′,4′′-(1,3,5-triazine-2,4,6-triyl)tribenzaldehyde at different ratios, and the stationary phases prepared from them after coating with silica gel, all contain the characteristic diffraction peaks of chiral covalent organic framework materials. This demonstrates that within the scope of this invention, different ratios of quinazolinone diamine chiral precursors and 4,4′,4′′-(1,3,5-triazine-2,4,6-triyl)tribenzaldehyde can all yield chiral COF nanoparticles with the same structure, and indicates that two-dimensional honeycomb-type chiral covalent organic frameworks with well-defined structures have been successfully coated onto the surface of ammoniated silica gel.

[0093] The macroporous amination silica gel (average pore size of 100 nm) can be synthesized according to the reference (J. Chromatogr. A, 2008, 1213:162), or other commercially available amination silica gels with similar pore sizes can be used as raw materials.

[0094] Specific raw material information is shown in Table 1: Table 1. Raw Material Information

[0095] Preparation method of the chiral precursor of quinazolinone diamine described in Example 1 The preparation process of the chiral precursor of the quinazolinone diamine is as follows: Figure 2 .

[0096] Specifically, it includes the following steps: (1) Synthesis of Compound 1: N,Nˊ-dicyclohexylcarbodiimide (495 mg, 2.4 mmol), N-Boc-L-proline (430 mg, 2 mmol), and dimethyl 2-aminoterephthalate (504 mg, 2 mmol) were dispersed in tetrahydrofuran and stirred at room temperature for 72 hours. 100 mL of water was added to the reaction mixture, and the organic phase was extracted with ethyl acetate. After washing, drying, and concentration, petroleum ether:n-hexane (1:1, v / v) was added, and the precipitated grayish-white solid was separated by filtration. 10 mL of trifluoroacetic acid was added to dissolve and clarify the solid. After reacting for 2 hours, saturated NaHCO3 solution was added until the pH reached 7-9. The organic phase was extracted with dichloromethane and evaporated to dryness to give Compound 1 (light brown solid, 590 mg), yield 75%.

[0097] 1 H-NMR (400 MHz, DMSO- d 6) δ(ppm) = 11.86 (s, 2H), 9.29 (s, 2H), 4.38 (q, 4H), 3.77 (q, 2H), 3.01 – 3.00 (dt, 2H), 2.82 – 2.80 (dt, 2H), 2.09 – 2.03 (m,2H), 1.86 – 1.81 (m, 2H), 1.66 – 1.61 (m, 4H), 1.36 (t, 6H).

[0098] (2) Synthesis of chiral precursor of quinazolinone diamine: Compound 1 (0.590 g, 1.4 mmol) was placed in a pressure-resistant tube under argon protection, and 2.6 mL of methanol and 1.7 mL of 98% hydrazine hydrate were added. The mixture was stirred at 80 °C for 48 hours, filtered and washed with 1 mL of methanol, and dried to obtain a white solid powder (326 mg), with a yield of 60%.

[0099] The 1H NMR spectrum of the chiral precursor of the quinazolinone diamine is shown below. Figure 9 .

[0100] 1 H-NMR (400 MHz, DMSO- d 6)δ (ppm) = 8.23 ​​(s, 2H), 5.79 (s, 4H), 4.58 (q, 2H), 3.17 – 3.11 (m, 4H), 2.82 – 2.81 (dt, 2H), 2.26 – 2.20 (m, 2H), 1.95 – 1.90(m, 2H), 1.80 – 1.70 (m, 4H).

[0101] Example 2: Preparation of a silica gel stationary phase coated with quinazolinone-based chiral COF nanoparticles The quinazolinone-based chiral COF nanoparticle-coated silica gel stationary phase provided by this invention is composed of... Figure 1 The preparation was achieved using the process shown.

[0102] Specifically, the steps include the following: 8.0 mg of the chiral precursor of quinazolinone diamine prepared in Example 1 and 8.0 mg of 4,4′,4′′-(1,3,5-triazine-2,4,6-triyl)tribenzaldehyde were weighed into a pressure-resistant tube, followed by the addition of 1 mL of trifluoroacetic acid. After thorough mixing, 0.5 mL of water was added, and the mixture was placed in an oven preheated to 40°C for 3 days. After the reaction was completed, the solid was filtered off and washed successively with trifluoroacetic acid, water, and methanol. Finally, it was vacuum dried at 80°C to obtain 10.7 mg of chiral COF nanoparticles as a pale yellow solid powder, with a yield of 67%. 10.0 mg of chiral COF nanoparticles and 95.0 mg of ammoniated silica gel were weighed into a round-bottom flask, and 20 mL of methanol was added. The mixture was mechanically stirred for 0.5 h and then evaporated to dryness. This operation was repeated 3 times to obtain 95.1 mg of silica gel stationary phase coated with quinazolinone-based chiral COF nanoparticles, with a yield of 91%.

[0103] Detection example The performance test results of the silica gel stationary phase coated with quinazolinone-based chiral COF nanoparticles prepared in Example 2 are as follows: (1) X-ray powder diffraction determination Figure 3 The X-ray powder diffraction pattern of the silica gel stationary phase coated with quinazolinone-based chiral COF nanoparticles provided in this embodiment is shown below. Figure 3 (a) in the image represents chiral COF nanoparticles without ammoniated silica coating. Figure 3 (b) in the image represents a silica gel stationary phase coated with quinazolinone-based chiral COF nanoparticles. Figure 3 (c) in the diagram represents ammoniated silica gel. Comparing the X-ray powder diffraction patterns of the three, it can be seen that the present invention successfully synthesized a chiral COF and successfully coated it onto ammoniated silica gel.

[0104] (2) Fourier transform infrared measurement Figure 4 Fourier transform infrared (FTIR) spectra of the silica gel stationary phase coated with quinazolinone-based chiral COF nanoparticles provided in this embodiment. Figure 4 (a) is a chiral precursor of quinazolinone diamine. Figure 4 (b) in the text is 4,4′,4′′-(1,3,5-triazine-2,4,6-triyl)tribenzaldehyde. Figure 4 (c) in the figure represents chiral COF nanoparticles. Figure 4In the image (d), the silica gel stationary phase is coated with quinazolinone-based chiral COF nanoparticles. Comparison revealed that the infrared spectrum of the silica gel stationary phase coated with chiral COF nanoparticles contains the characteristic peaks of chiral COF nanoparticles, but lacks the characteristic peaks corresponding to the chiral precursor of quinazolinone diamine and 4,4′,4′′-(1,3,5-triazine-2,4,6-triyl)tribenzaldehyde.

[0105] (3) Scanning electron microscopy determination Figure 5 A scanning electron microscope (SEM) image of the silica gel stationary phase coated with quinazolinone-based chiral COF nanoparticles provided in this embodiment, wherein... Figure 5 (a) in the image represents chiral COF nanoparticles. Figure 5 (b) in the image represents a silica gel stationary phase coated with quinazolinone-based chiral COF nanoparticles. Figure 5 (c) in the diagram represents ammoniated silica gel. By comparing the scanning electron microscope images of the three, it can be confirmed that the present invention successfully coated chiral COF onto ammoniated silica gel to prepare a chiral COF nanoparticle-coated silica gel stationary phase.

[0106] (4) Thermogravimetric analysis Figure 6 The thermogravimetric analysis curves of the silica gel stationary phase coated with quinazolinone-based chiral COF nanoparticles provided in this embodiment under nitrogen atmosphere show good thermal stability.

[0107] (5) High performance liquid chromatography separation The silica gel stationary phase coated with quinazolinone-based chiral COF nanoparticles provided in this embodiment was filled into a 150×4.6 mm ID stainless steel column by homogenization and applied to the high-performance liquid chromatography separation of chiral isomers. Figure 7 These are the corresponding high-performance liquid chromatograms, where (a), (b), and (c) represent 1-(3-methoxyphenyl)ethylamine, 1-(4-methoxyphenyl)ethylamine, or 2-hydroxy-1,2-di(thienyl)ethane-1-one, respectively. As shown in the figure, the silica gel stationary phase coated with quinazolinone-based chiral COF nanoparticles provided in this embodiment can effectively separate the chiral isomers. Analysis shows that column pressure is the pressure of the mobile phase passing through it, and column efficiency is reflected by the "plate number," according to... Figure 7 According to the records, the column pressure of the silica gel stationary phase coated with quinazolinone-based chiral COF nanoparticles provided in the embodiments of this application can reach 2.0 MPa, and the number of trays is 1500-2500.

[0108] Figure 8 When using commercial OD and AD columns (150×4.6 mm ID) for high-performance liquid chromatography separation of the chiral isomers of 1-(3-methoxyphenyl)ethylamine, effective separation cannot be achieved.

[0109] Verification of technical effectiveness and / or analysis of technical problem solving This invention, through structural design, preparation process optimization, and chromatographic performance verification, systematically demonstrates that the prepared quinazolinone-based chiral COF nanoparticle-coated silica stationary phase successfully solves several key technical problems existing in current chiral COF chromatographic stationary phases.

[0110] 1. Successful load verification of structural clarity and chiral COF X-ray powder diffraction (XRD) results showed that the obtained quinazolinone-based chiral COF nanoparticles possessed a typical two-dimensional honeycomb-like layered crystalline structure, with clear and stable characteristic diffraction peaks. The silica gel stationary phase coated with the quinazolinone-based chiral COF nanoparticles simultaneously retained the characteristic diffraction signals of both the ammoniated silica gel and the chiral COF, proving that the chiral COF crystal structure was not destroyed during the coating process and was successfully loaded onto the silica gel surface. Fourier transform infrared spectroscopy further confirmed the presence of characteristic absorption peaks of the COF framework in the stationary phase, indicating a stable interfacial interaction between the quinazolinone-based chiral COF and the ammoniated silica gel, with a well-defined structural composition and reliable bonding / loading mechanism.

[0111] 2. Verification of the compatibility between morphological uniformity and column pressure and column efficiency. Scanning electron microscopy (SEM) results show that the chiral COF prepared in this invention is uniformly distributed in the form of nanoparticles on the surface of ammoniated silica gel, without obvious agglomeration, accumulation, or pore blockage. The particle size is uniform and the coating is continuous. This morphological feature directly solves the common industry problems of high column pressure, large mass transfer resistance, and low column efficiency when traditional chiral COF microcrystalline powder is used to fill chromatographic columns. The prepared silica gel stationary phase has a smooth surface, high mechanical strength, and good flowability, which can meet the usage requirements of conventional flow rate and pressure ranges in high-performance liquid chromatography, and has the structural basis for practical chromatographic applications.

[0112] 3. Verification of thermal stability and chromatographic reliability Thermogravimetric analysis (TGA) results showed that the quinazolinone-based chiral COF nanoparticle-coated silica stationary phase maintained stable quality over a wide temperature range, exhibiting excellent thermal stability. During chromatographic separation, this stationary phase can withstand conventional mobile phase composition, flow rate, and temperature conditions, and is less prone to backbone collapse, loss of chiral sites, or coating peeling. Its service life and durability are significantly improved, overcoming the technical shortcomings of some existing chiral COF stationary phases, such as poor stability, easy swelling, and large batch-to-batch variations.

[0113] 4. Verification of chiral separation performance and technical advantages Coating quinazolinone-based chiral COF nanoparticles with a silica gel stationary phase for high-performance liquid chromatography (HPLC) enables the efficient separation of various chiral isomers, including 1-(3-methoxyphenyl)ethylamine, 1-(4-methoxyphenyl)ethylamine, and 2-hydroxy-1,2-di(thienyl)ethane-1-one. Under the same testing conditions, commercially available OD and AD columns failed to achieve satisfactory separation of these compounds, while the stationary phase of this invention exhibited stronger chiral recognition capability and higher selectivity.

[0114] The fundamental reason is that the rigid framework of the quinazolinone heterocycle and the chiral proline unit together construct multiple chiral recognition sites, which can achieve enantioselective recognition and separation through multiple forces such as hydrogen bonding, π-π stacking, spatial matching and dipole interaction, thus solving the problem of single chiral sites and limited recognition efficiency of existing chiral COF stationary phases.

[0115] 5. Verification of the controllability and practicality of the preparation process This invention employs a stepwise synthesis, mild reaction, and uniform nanoparticle coating strategy, ensuring mild and reproducible conditions throughout the entire process from chiral precursor synthesis and COF nanoparticle preparation to silica gel loading. Compared to complex routes such as in-situ growth and covalent bonding, this method is simple to operate, allows for controllable loading, and facilitates easy product separation and purification. It effectively avoids problems such as uneven COF growth on silica gel surfaces, damage to chiral structures, and difficulties in post-processing. The prepared stationary phase exhibits high batch-to-batch stability, making it more suitable for industrial-scale preparation and practical application.

[0116] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A silica gel stationary phase coated with quinazolinone-based chiral COF nanoparticles, characterized in that, The raw materials include: a chiral precursor of quinazolinone diamine having the structure shown in formula (I), 4,4′,4′′-(1,3,5-triazine-2,4,6-triyl)tribenzaldehyde, and silica gel; Equation (Ⅰ).

2. The silica gel stationary phase according to claim 1, characterized in that, The silicone is ammoniated silicone; The molar ratio of the chiral precursor of quinazolinone diamine to 4,4′,4′′-(1,3,5-triazine-2,4,6-triyl)tribenzaldehyde is 1:0.5-4.

3. The silica gel stationary phase according to claim 1, characterized in that, The method for preparing the chiral precursor of the quinazolinone diamine includes the following steps: (1) N,Nˊ-dicyclohexylcarbodiimide, N-Boc-L-proline and 2-aminoterephthalate were dispersed in an organic solvent and reacted. After solid-liquid separation and purification, an acidic deprotecting agent was added to obtain an intermediate. (2) The intermediate obtained in step (1) is subjected to hydrazine hydrate reaction and purified to obtain the final product.

4. The method for preparing the silica gel stationary phase according to any one of claims 1-3, characterized in that, Including the following steps: (1) The chiral precursor of the quinazolinone diamine was reacted with 4,4′,4′′-(1,3,5-triazine-2,4,6-triyl)tribenzaldehyde in an organic solvent to obtain chiral COF nanoparticles; (2) The chiral COF nanoparticles obtained in step (1) are dispersed in an organic solvent and purified to obtain the final product.

5. The preparation method according to claim 4, characterized in that, The organic solvent in step (1) includes at least one of trifluoroacetic acid, 1,4-dioxane, tetrahydrofuran, acetonitrile, N,N-dimethylformamide, dimethyl sulfoxide, ethyl acetate, and dichloromethane.

6. The preparation method according to claim 5, characterized in that, The organic solvent in step (1) is a mixed solution of trifluoroacetic acid and water with a volume ratio of 1:0.1-1.

5.

7. The preparation method according to claim 4, characterized in that, The reaction temperature in step (1) is 25-80℃; the reaction time in step (1) is 2-7 days; The reaction described in step (1) also includes steps of filtration, washing, and drying.

8. The preparation method according to claim 4, characterized in that, The mass ratio of the chiral COF nanoparticles to the ammoniated silica gel in step (2) is 1:2-12; The organic solvent in step (2) includes at least one of methanol, ethanol, isopropanol, n-propanol, acetonitrile, ethyl acetate, or tetrahydrofuran; The purification process in step (2) includes filtration and drying.

9. The application of the silica gel stationary phase according to any one of claims 1-3 in high performance liquid chromatography separation.

10. A high-performance liquid chromatograph containing the silica gel stationary phase according to any one of claims 1-3.

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