A screening method based on cinnamyl phenylpropanoid and its application

Abstract

The present application relates to the technical field of component design, and particularly relates to a screening method of a benzenic acid group substitution type based on isoamyl cinnamate and application thereof, the screening method comprising the following steps: establishing a virtual substituent library, introducing acid group substituents on a benzene ring of isoamyl cinnamate to generate a plurality of substitution combinations; predicting an acid dissociation constant minimum value pKai and a proportion of polar atoms PAR for each structure, and screening <= 50 candidate structures according to the pKai and the PAR; measuring a fluorescence polarization anisotropy r of each candidate structure, and screening the first 50% samples in the order of r values from small to large; measuring quantum dot fluorescence intensity retention rates F of the screened samples in sequence ret and coating UVB retention rates RA UVB ; and outputting an acid group substitution type corresponding to a maximum value in the order of products of the two. The acid group substitution type has the ability of resisting ultraviolet attenuation and the protection effect of a photosensitive component, and ensures that the preferred structure has self stability and synergistic protection in a real complex system.

Description

Technical Field

[0001] This invention relates to the field of component design technology, and in particular to a method for screening the phenyl cyclic acid substitution type based on isoamyl cinnamate and its application. Background Technology

[0002] Currently, isoamyl cinnamate derivatives have become the mainstream research focus for high-efficiency UV-resistant additives due to their significant UV absorption properties. Furthermore, in the molecular design of photostable additives, acid group functionalization is considered a key pathway to improve water solubility and emulsifying efficiency. Therefore, phenyl ring acid substitution based on isoamyl cinnamate has become the main method for improving its performance.

[0003] However, existing screening systems are limited by static evaluation. Evaluating single-point parameters makes it difficult to intuitively characterize the gain mechanism of acid-base polarity networks anchoring at interfaces. For example, QSAR models based on quantum chemical calculations can quickly predict parameters such as lipophilicity (LogP) and molar absorptivity of molecules. This method can complete the theoretical evaluation of thousands of structures within hours, significantly reducing initial R&D costs. However, it can only predict the molecule's own properties, such as UV absorption intensity, completely ignoring its protective efficacy against other photosensitive components in the formulation (such as vitamin C). Pseudo-high-scoring molecules fail in compound systems because they cannot protect photosensitive materials. While experimental testing can reflect the performance of the compound system, it cannot distinguish the independent contributions of its own stability and material protection ability. Furthermore, relying solely on experimental testing requires the complete synthesis of physical compounds, leading to excessive R&D resources being consumed on low-potential molecules. The essence of this contradiction lies in the fact that UV-resistant additives in real-world applications need to simultaneously perform the dual functions of photostability and exogenous protective efficacy, but current technologies lack a synergistic mechanism for simultaneously quantifying these two properties. This results in repeated failures in selecting optimal structures, becoming a long-standing technical bottleneck in the industry.

[0004] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the present invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] The technical problem to be solved by this invention is to provide a screening method for the substitution type of phenyl cyclic acid groups based on isoamyl cinnamate, so as to obtain a structure with excellent performance and solve the problem of low development efficiency of anti-ultraviolet additives caused by the inability of existing technologies to take into account both their own photostability and their protective efficacy for photosensitive materials.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for screening the substitution type of phenyl cyclic acid groups based on isoamyl cinnamate includes the following steps:

[0008] A1 provides CdSe / ZnS core-shell quantum dot probes with surface-modified polyethylene glycol-acrylic acid copolymers;

[0009] A2 establishes a virtual substituent library by introducing acid substituents onto the benzene ring based on the isoamyl cinnamate core to generate multiple substitution combinations; predicts the minimum acid dissociation constant pKai for each structure, and calculates the polar atom ratio PAR; calculates the product of the absolute values ​​of the two and screens ≤50 candidate structures in descending order.

[0010] All 50 candidate structures retained meet the ionization performance requirements and have weak / moderate binding forces, making them suitable for fluorescence polarization detection in step A3 and avoiding the shading of the quantum dot surface in step A4.

[0011] A3 prepared each candidate structure into a 0.1 mg / mL aqueous solution and added a 0.1 μM quantum dot probe. The fluorescence polarization anisotropy (r) was measured, and the top 50% of samples were screened in ascending order. In practice, verification can be performed in batches according to the descending product of the absolute values ​​of pKai and PAR. If the total number of samples is ≤10, at least the top 5 should be screened. The reason for this test is that unmasked quantum dots can effectively disperse ultraviolet energy (Fret≥92%), while strongly adsorbed molecules will form a "dead layer," which will actually reduce the SPF value. This invention uses PEG-acrylic acid copolymer-modified CdSe / ZnS quantum dots for screening cinnamic acid ester derivatives, utilizing their fluorescence signal amplification and polarization response characteristics to achieve rapid binding capacity assessment.

[0012] A4 samples screened after A3 underwent the following parallel testing: In Group A, the quantum dot solution prepared in A3 was irradiated with UV-B to determine the quantum dot fluorescence intensity retention rate F. ret The photoprotective ability of molecules was characterized; Group B involved preparing a new pure sample aqueous solution without quantum dots, adding it at 0.5 wt% to a standard O / W sunscreen matrix, applying it, and then subjecting it to simulated sunlight irradiation to determine the UVB retention rate (RA) of the coating. UVB ;

[0013] A5 is based on S=RA UVB ×F ret Sort the samples and output the acid substitution type corresponding to the maximum value of S.

[0014] Preferably, in step A1, the modification with polyethylene glycol-acrylic acid copolymer can improve the water solubility and biocompatibility of quantum dots. In the polyethylene glycol-acrylic acid copolymer modification of the quantum dot probe, the molar ratio of polyethylene glycol to acrylic acid is 1:95-105. This ensures the surface carboxyl group density, which is beneficial for interaction with acid substituents. The CdSe core diameter of the quantum dot probe is 4.5±0.5nm, and the ZnS shell thickness is 1.0±0.2nm, so as to provide a stable fluorescence signal and meet the requirements of fluorescence polarization detection.

[0015] Preferably, step A2 eliminates systematic bias by reconstructing calculation rules, specifically including:

[0016] The isoamyl cinnamate structure was loaded into cheminformatics software such as ChemAxon or RDKit, and the 2, 3, 4, 5, and 6 positions of the benzene ring were defined as substitution sites.

[0017] Based on the isoamyl cinnamate core, acid substituents are introduced at the substitution sites to generate all possible mono / di substitution combinations. Specifically, mono substitution is the independent introduction of acid substituents at each site, and di substitution is a non-ortho combination. This step excludes sterically hindered combinations and trisubstitution combinations to avoid steric hindrance interference with subsequent detection.

[0018] Predict the acid dissociation constant of all acid substituents in each structure and take the minimum value as pKai; eliminate structures with |pKai|>4; this step screens structures with |pKa|≤4 to ensure that the substituents can ionize at physiological pH and enhance the interaction with quantum dots.

[0019] Calculate the polar atom ratio PAR, where PAR = number of polar atoms / total number of atoms. Polar atoms include oxygen, nitrogen, sulfur, and phosphorus. The polar atom ratio PAC = aN O +bN N +cN S +dN P N O N N N S N P , representing the number of oxygen, nitrogen, sulfur, and phosphorus atoms in the molecule, respectively. a, b, c, and d are correction coefficients, calibrated based on atomic polarizability, with a preferred value of a = 1, b = 1.2, c = 2, and d = 3. This strengthens the contribution weight of sulfur / phosphorus atoms to molecular polarity, highlighting the high coordination ability of sulfonic acid / phosphonic acid groups; and suppresses the artificially high scores of weak acid molecules containing multiple oxygen atoms (such as boric acid), improving the sensitivity to distinguish strong acid structures. The purpose of the initial screening of acidity and polarity in this invention is that the synergy between strong acid and high polarity can improve water solubility and realize high surface activity potential.

[0020] Preferably, the acid substituents include at least sulfonic acid, carboxyl, phosphoric acid, phosphonic acid, sulfonamide, oxalyl, and their ionized forms. This enriches the sample library, allowing the screening system to overcome the limitations of traditional carboxylic acid / sulfonic acid systems and uncover non-classical structures with high photostability and high protective efficacy.

[0021] Preferably, step A3 uses a 96-well plate for high-throughput screening, which can complete the evaluation of the quantum dot protection efficacy of 50 candidate molecules within 72 hours, with a data dispersion RSD < 6%. The 96-well plate is made of black polypropylene with an optical transmittance of > 90% at the bottom of the well. The liquid volume per well is 100 ± 2 μL, and each plate contains 4 wells of blank control + 4 wells of standard control.

[0022] Preferably, in step A3, during fluorescence polarization measurement, the excitation wavelength is 365±5nm to cover the π-π* transition absorption peak of cinnamic ester and avoid interference from extraneous peaks; the emission wavelength is 610±5nm to match the maximum emission band of the quantum dot and eliminate signal attenuation caused by Stokes shift. The formula for calculating the fluorescence polarization anisotropy value r is as follows:

[0023]

[0024] Where I1 is the intensity of vertically polarized light and I2 is the intensity of parallelly polarized light.

[0025] Preferably, in step A4...

[0026] Group A's UV-B irradiation was conducted at a dominant wavelength of 311±2 nm and an irradiation intensity of 0.50±0.05 mW / cm². 2 The cumulative exposure time was 120±5 min to accurately simulate the peak of the solar spectrum and avoid false negatives caused by overexposure. The fluorescence intensity of the quantum dots was measured before and after irradiation, and the fluorescence intensity retention rate F of the quantum dots was measured. ret =(F 辐照后 / F 辐照前 )×100%;

[0027] Group B testing involved adding a newly prepared pure sample aqueous solution to a standard O / W sunscreen matrix, homogenizing it, and then coating it onto a quartz plate for cumulative 30.0 ± 0.5 kJ / m² testing. 2 Irradiation, 30.0±0.5kJ / m 2 The cumulative irradiation dose is equivalent to the average daily UV exposure of the human body, making the RAUBB data directly relevant to actual use scenarios. The integrated absorbance from 290 to 320 nm was measured sequentially using a micro-UV spectrometer before and after irradiation to calculate the UVB retention rate (RA). UVB Among them, RA UVB =(UVB) 辐照后 / UVB 辐照前 )×100%.

[0028] As a preferred option,

[0029] Based on weight percentage, the standard O / W sunscreen base includes 5.0% glycerin, 3.0% polyglycerol-3-methyl glucoside, 0.5% xanthan gum, and the balance water;

[0030] The coating thickness was 2.0 ± 0.2 mg / cm. 2 Irradiation was performed using a xenon lamp aging apparatus.

[0031] The detection points are located using laser micro-engraving. Specifically, multiple detection points are laser micro-engraved on a quartz sheet before coating, and the integrated values ​​of 290–320 nm at multiple points are measured before exposure to sunlight, and the average value is taken to obtain the UVB value. 辐照前 UVB levels were obtained by retesting in situ after exposure to sunlight and taking the average value. 辐照后 .

[0032] Preferably, in step A5, the present invention is performed according to S=RA. UVB ×F ret The maximum S-value was ranked and output to quantify the dual function of sunscreen agents. The position of the sulfonic acid group in the raw material was determined by a screening method, which ultimately output a disulfonic acid substitution configuration at the 2- and 4-positions of the benzene ring. This configuration naturally prevailed in the S-value ranking due to the ultra-high surface binding strength of the meta-disulfonic acid on the benzene ring, the photo-oxidation resistance of the sulfonic acid group, and the shielding protection effect on quantum dots, thus verifying the effectiveness of the screening system.

[0033] This configuration achieves both high photostability and strong protection for photosensitive components. The strong electron-withdrawing effect of the disulfonic acid group at the 2,4-position of the benzene ring forms a D-π-A structure with the conjugated bond of cinnamic acid olefin, significantly reducing the π-π* transition energy level and precisely red-shifting the maximum absorption wavelength to the core UV-B band. The symmetrical substitution of disulfonic acid maintains the conjugated planarity, avoiding steric hindrance while enhancing water solubility through sulfonic acid group ionization and synergistically forming a broad-spectrum absorption of 280–320 nm, greatly improving UV coverage efficiency. The meta-disulfonic acid substitution stabilizes the conjugated system through an intramolecular hydrogen bond network, endowing it with excellent resistance to photodegradation. It maintains highly efficient UV shielding function even under long-term sunlight exposure, providing long-lasting protection against UVB damage to the skin. The non-planar adsorption characteristics allow it to generate only weak binding when protecting photosensitive components, perfectly balancing its own photostability and the protective efficacy of the photosensitive material, fundamentally solving the problem of optical material failure caused by the strong shielding effect of traditional sunscreens.

[0034] The strong hydrophilicity of the disulfonic acid group makes it highly soluble in aqueous systems, avoiding the problem of traditional oil-soluble sunscreens requiring a large amount of surfactant for solubilization. Its ionization properties enable it to be well-compatible with various sunscreen bases (O / W, W / O, silicone oil-based, etc.), making it widely adaptable to formulations. The synergistic effect of the intramolecular hydrogen bond network and conjugated system ensures its stability in high temperature and high humidity environments, and it has outstanding resistance to sweat rinsing. In actual use, it is not easily washed away by sweat, and can be used as a highly effective sunscreen active ingredient. Furthermore, it can be extended to the field of functional products such as anti-photoaging cosmetics.

[0035] The second objective of this invention is to provide isoamyl 2,4-disulfonic acid cinnamate obtained by the above screening method, for use in anti-ultraviolet agents and sunscreens, simultaneously quantifying the molecular photostability and exogenous protective efficacy.

[0036] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0037] A method for synthesizing isoamyl cinnamate 2,4-disulfonic acid, using 4-formyl-1,3-benzenedisulfonic acid, diethyl malonate and isoamyl alcohol reacted under the catalysis of catalyst P;

[0038] Catalyst P is R1 is an alkyl group, and R2 is an aromatic group.

[0039] This invention utilizes 4-formyl-1,3-benzenedisulfonic acid as a key raw material, leveraging the strong electron-withdrawing effect and steric hindrance of its 1,3-position disulfonic acid group to ensure the reaction specifically occurs at the 4-position aldehyde group. This results in a regioselectivity of over 99% for the 2,4-disulfonic acid configuration of the product, fundamentally avoiding the impurity problems such as the 2,5-isomer produced by traditional sulfonation methods. Secondly, the innovative introduction of a pyrrole derivative catalyst further suppresses side reactions and improves the condensation reaction yield due to the steric hindrance of the pyrrole ring. The obtained product meets the requirements for fluorescence polarization r-value and comprehensive performance score S, exhibiting both excellent UV absorption capacity and quantum dot protection function. This method is highly atom-economical and environmentally friendly, providing a key raw material guarantee for the development of novel sunscreen materials.

[0040] The reaction equation is as follows:

[0041]

[0042] The present invention provides a synthetic method for obtaining isoamyl 2,4-disulfonic acid cinnamate that meets the above-mentioned properties, avoiding excessive 2,5-byproducts during atmospheric pressure sulfonation and ensuring that the purity of the target product is >98%.

[0043] As a preferred embodiment, the synthesis method includes the following steps:

[0044] (a) Diethyl malonate and dry isoamyl alcohol are mixed and added to a reaction vessel. A solution of potassium hydroxide in isoamyl alcohol is slowly added dropwise at -5°C. The mixture is stirred at room temperature for 4 to 8 hours to generate potassium isoamyl malonate.

[0045] (b) Add glacial acetic acid in equimolar amounts to potassium hydroxide to neutralize excess KOH and prevent the condensation of aldehyde groups from running out of control under a strong alkaline environment. Stir the reaction at ≤30℃ for 1 to 3 hours.

[0046] (c) Add 4-formyl-1,3-benzenedisulfonic acid and catalyst P, and heat under reflux for 5 to 7 hours;

[0047] (d) Unreacted isoamyl alcohol was recovered by vacuum distillation at -0.095 MPa, and then 2 to 5 times the volume of pure water was added and cooled to 0-10℃ to crystallize and obtain the target compound, isoamyl 2,4-disulfonic acid cinnamic acid.

[0048] In step (a), diethyl malonate and isoamyl alcohol are mixed in a molar ratio of 1:(4-8), and the mass ratio of potassium hydroxide in the isoamyl alcohol solution is 10-30 wt%.

[0049] In step (c), the molar ratio of 4-formyl-1,3-benzenedisulfonic acid to diethyl malonate is 1:(1.1–1.5), and the amount of catalyst P added is 5–8% of the mass of 4-formyl-1,3-benzenedisulfonic acid. The reflux temperature is 130 ± 2 °C.

[0050] The reaction employs a one-pot synthesis method, which reduces the difficulty of synthesizing strong acid-substituted cinnamic esters. In addition, the catalyst P used has excellent catalytic effect, which greatly improves the selectivity and conversion rate of the reaction compared with other catalysts.

[0051] The beneficial effects of this invention are as follows:

[0052] This invention employs virtual screening to calculate the minimum acid dissociation constant pKai and the polar atom ratio PAR, and then calculates the product of their absolute values, screening ≤50 candidate structures in descending order of value, thus avoiding the resource waste caused by traditional blind synthesis. Next, it uses quantum dot probes to quantify the binding affinity between sunscreen agents and photosensitive materials in real time via fluorescence polarization, overcoming the core defect of traditional virtual screening's inability to predict molecular protective efficacy. Finally, it synchronously outputs RA through dual-path photostable detection. UVB and F ret It demonstrates its own ability to resist ultraviolet decay and the protective effect of photosensitive components. The two work together to achieve the mathematical coupling of dual functions, ensuring that the optimized structure has both its own stability and synergistic protection in the real compound system.

[0053] This invention uses the above screening method to obtain disulfonic acid group substitution configurations at the 2- and 4-positions of the benzene ring. Group A was tested using quantum dot probes to verify its photoprotective ability; after irradiation, the quantum dot fluorescence retention rate (Fret) was ≥95%, demonstrating its highly efficient UV filtering capability. Group B was tested to assess its long-term stability in the sunscreen matrix. The disulfonic acid group substitution enhances molecular polarity, resulting in a directional distribution at the oil-water interface in O / W sunscreen matrices. The hydrophilic sulfonic acid group anchors the aqueous phase, while the hydrophobic isoamyl ester chain inserts into the oil phase, forming a molecular-level UV shielding film, exhibiting breakthrough advantages in UV absorption characteristics and sun protection effect. Attached Figure Description

[0054] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0055] Figure 1 This is a flowchart of the screening method of the present invention. Detailed Implementation

[0056] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0057] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0058] Example 1

[0059] like Figure 1 As shown, this embodiment provides a method for screening the substitution type of phenyl cyclic acid groups based on isoamyl cinnamate, including the following steps:

[0060] A1 provides CdSe / ZnS core-shell quantum dot probes with surface-modified polyethylene glycol-acrylic acid copolymers;

[0061] Among them, modification with polyethylene glycol-acrylic acid copolymer can improve the water solubility and biocompatibility of quantum dots. In the polyethylene glycol-acrylic acid copolymer modification of quantum dot probes, the molar ratio of polyethylene glycol to acrylic acid is 1:95-105. This ensures the surface carboxyl group density, which is conducive to the interaction with acid substituents. The CdSe core diameter of the quantum dot probe is 4.5±0.5nm, and the ZnS shell thickness is 1.0±0.2nm, so as to provide a stable fluorescence signal and meet the requirements of fluorescence polarization detection.

[0062] Specifically, 1 mmol of polyethylene glycol monomethyl ether (Mn = 2000) and 100 mmol of acrylic acid were added to a reaction vessel, nitrogen was purged to remove oxygen, and 0.1 mmol of AIBN was added. The reaction was carried out at 70°C for 24 hours to obtain a copolymer with a PEG:acrylic acid molar ratio of 1:100. The copolymer was dissolved in chloroform at a concentration of 10 mg / mL, and then added to a CdSe / ZnS quantum dot solution at a quantum dot surface area:copolymer carboxyl group number ratio of 1:500 (molar ratio). The mixture was shaken in a water bath at 40°C for 12 hours. Free polymer was removed by ultracentrifugation, and the precipitate was resuspended in ultrapure water and stored at 4°C in the dark.

[0063] A2 establishes a virtual substituent library by introducing acid substituents onto the benzene ring based on the isoamyl cinnamate core to generate multiple substitution combinations; predicts the minimum acid dissociation constant pKai for each structure, and calculates the polar atom ratio PAR; calculates the product of the absolute values ​​of the two and screens ≤50 candidate structures in descending order.

[0064] Specifically, step A2 eliminates systematic biases through rule reconstruction, including:

[0065] The isoamyl cinnamate structure was loaded into cheminformatics software such as ChemAxon or RDKit, and the 2, 3, 4, 5, and 6 positions of the benzene ring were defined as substitution sites. Sulfonic acid groups, carboxyl groups, phosphoric acid groups, phosphonic acid groups, sulfonamide groups, oxalyl groups and their ionized forms were introduced at the substitution sites to generate all possible mono / di-substituted combinations.

[0066] Specifically, in this embodiment, isoamyl cinnamate (CC(C)CCOC(=O)C=CC1=CC=CC=C1) is loaded into ChemAxon JChem to lock the substitution sites on the benzene ring. The input acid group is subjected to mono- or di-substitution, where mono-substitution involves replacing one H atom, and di-substitution involves replacing two non-ortho-H atoms. This step excludes sterically hindered combinations and tri-substitution combinations to avoid steric hindrance interference with subsequent detection. pKai prediction is performed using ChemAxon pKa Plugin (v22.15) with parameters set to a temperature of 25.0℃, an ionic strength of 0.15M, and an ambient pH of 7.4. Tautomer analysis is enabled, and the minimum dissociation constant of all acid groups is taken as pKai. Significant deviations can occur due to electronic effects and steric hindrance between di-acid groups. Parameter corrections are performed for di-substituted acid groups during the process, as shown in Table 1 below.

[0067] Table 1

[0068] acid type Correction value sulfonic acid group -0.30 carboxylic acid group +0.20 Phosphate +0.10 Phosphonic acid group -0.45 sulfonamide group +1.20 oxaloyl +0.35

[0069] This correction value is based on experience, and Table 2 below shows some data verification:

[0070] Table 2

[0071] Molecular structure Predictions for pKai (uncorrected) pKai (corrected) Experimental values 2-Sulfonic acid-4-carboxylic acid group -1.85 -1.65 -1.62 4-phosphono-2-sulfonamide -0.92 -1.37 -1.40 3-Oxaloyl-5-sulfonic acid group -2.30 -1.95 -1.98

[0072] This step screens for structures with |pKa|≤4 to ensure that the substituents are ionizable at physiological pH, thereby enhancing their interaction with quantum dots.

[0073] Calculate the polar atom ratio PAR, where PAR = number of polar atoms / total number of atoms. Polar atoms include oxygen, nitrogen, sulfur, and phosphorus. The polar atom ratio PAC = aN O +bN N +cN S +dN P N O N N N S N P These represent the number of oxygen, nitrogen, sulfur, and phosphorus atoms in the molecule, respectively. a, b, c, and d are correction coefficients, calibrated based on atomic polarizability; for example, a = 1, b = 1.2, c = 2, and d = 3 are preferred. This strengthens the contribution weight of sulfur / phosphorus atoms to molecular polarity, highlighting the high coordination ability of sulfonic acid / phosphonic acid groups; and suppresses the artificially high scores of weak acid molecules containing multiple oxygen atoms (such as boric acid), improving the sensitivity to distinguish strong acid structures. The purpose of the initial screening of acidity and polarity in this invention is that the synergy between strong acid and high polarity can improve water solubility and realize high surface activity potential.

[0074] Then, the product of the absolute values ​​of the two is calculated, and ≤50 candidate structures are screened in descending order. The 50 retained candidate structures all meet the ionization performance requirements, have weak / moderate binding forces, are suitable for fluorescence polarization detection in step A3, and avoid obscuring the quantum dot surface in step A4. In this step, the TOP 10 representative structures include: disulfonic acid group, sulfonic acid group-phosphonic acid group, sulfonic acid group-oxalyl group, sulfonic acid group-carboxylic acid group, sulfonic acid group-carboxylic acid group, sulfonamide group-sulfonic acid group, phosphonic acid group-oxalyl group, sulfonic acid group-phosphate group, carboxylic acid group-oxalyl group, diphosphonic acid group, and sulfonic acid group (monosubstituted).

[0075] A3 prepared each candidate structure into a 0.1 mg / mL ultrapure aqueous solution and added a 0.1 μM quantum dot probe. The fluorescence polarization anisotropy r was measured, and the top 50% of samples were screened in ascending order. In practice, verification can be performed in batches according to the descending product of the absolute values ​​of pKai and PAR. If the total sample size is ≤10, at least the top 5 should be screened. This invention uses PEG-acrylic acid copolymer-modified CdSe / ZnS quantum dots for screening cinnamic acid ester derivatives, utilizing their fluorescence signal amplification and polarization response characteristics to achieve rapid binding capacity assessment.

[0076] Specifically, a 96-well plate high-throughput screening was used. 80 μL of solution was added to a black 96-well plate, and 20 μL of 0.5 μM quantum dot probe (final concentration 0.1 μM) was added to each well. A PerkinElmer EnVision multi-mode plate reader was used to measure the intensity of vertically polarized light (I1) and parallelly polarized light (I2) at an excitation wavelength of 365 nm and an emission wavelength of 610 nm. The fluorescence polarization anisotropy value r was calculated. The formula for calculating the fluorescence polarization anisotropy value r is as follows:

[0077]

[0078] Where I1 represents the intensity of vertically polarized light and I2 represents the intensity of parallelly polarized light. The fluorescence polarization anisotropy value is used to quantify the orientational order of fluorescent molecules under polarized light excitation, reflecting the molecular rotational degrees of freedom or the binding state with the surrounding environment. In this invention, the strength of the molecule-nanoparticle interaction is determined by the change in the r value. Preferably, r ≤ 0.15, at which point the binding force between the molecule and the quantum dot is moderate and will not obscure its surface active sites. The reason for conducting this test in this invention is that unobscurified quantum dots can effectively disperse ultraviolet energy (F...). ret (≥92%), while strongly adsorbed molecules can form a "dead layer," which actually reduces the SPF value. Furthermore, weak binding improves the potential matching effect with the sunscreen matrix, preventing flocculation.

[0079] This invention can evaluate the quantum dot protection efficacy of 50 candidate molecules within 72 hours, with a data dispersion RSD < 6%. The 96-well plate is made of black polypropylene with a well bottom optical transmittance > 90%. Each well contains 100 ± 2 μL of solution, and each plate includes 4 wells of blank control (quantum dot solution only) + 4 wells of standard control (0.1 mM octocrylene). Specifically, during fluorescence polarization measurement, the excitation wavelength is 365 ± 5 nm to cover the cinnamate π-π* transition absorption peak and avoid interference from extraneous peaks; the emission wavelength is 610 ± 5 nm to match the maximum emission band of the quantum dots and eliminate signal attenuation caused by Stokes shift.

[0080] The A4 samples screened after A3 underwent the following parallel tests: In Group A, the quantum dot solution prepared in A3 was irradiated with UV-B to determine the quantum dot fluorescence intensity retention rate (Fret), characterizing the molecular photoprotective ability. In Group B, a pure sample aqueous solution without quantum dots was prepared and added at 0.5 wt% to a standard O / W sunscreen matrix. After coating, the sample was irradiated with simulated sunlight, and the UVB retention rate (RA) of the coating was determined. UVB ;

[0081] In step A4,

[0082] Group A's test results were:

[0083] Take the quantum dot solution prepared in A3 and dilute it to 50 nM with PBS buffer at pH 7.4. Vortex at 800 rpm in the dark for 30 s, then let it stand for 15 min to ensure uniform dispersion of the complex. Then load it into a 96-well plate, add 100 μL of quantum dot solution to each well, and set up replicates (n=6). Set up unreconstituted quantum dot solution and PBS buffer as controls.

[0084] Before irradiation, the fluorescence intensity of the quantum dots was measured using an EnVision plate reader; they were then subjected to UV-B irradiation in a 96-well UV-B irradiator with a dominant wavelength of 311±2 nm and an irradiation intensity of 0.50±0.05 mW / cm². 2 The cumulative exposure time was 120±5 min to accurately simulate the peak value of the solar spectrum and avoid false negatives caused by overexposure. During the process, the infrared thermal imager monitored the surface temperature of the plate, and the cooling fan was activated when the temperature exceeded 28°C to prevent thermal quenching. The fluorescence intensity of the quantum dots was measured using an EnVision plate reader within 10 min after irradiation. Finally, the fluorescence intensity retention rate F of the quantum dots was calculated. ret =(F 辐照后 / F 辐照前 )×100%;

[0085] Group B's test results were:

[0086] The newly prepared pure sample aqueous solution was added at 0.5 wt% to a standard O / W sunscreen matrix and emulsified using a homogenizer. The emulsion was then coated onto a laser-micro-marked quartz plate, with a coating thickness of 2.0 ± 0.2 mg / cm². 2 Then, a xenon lamp aging tester was used to accumulate 30.0±0.5kJ / m. 2 Irradiation, 30.0±0.5kJ / m 2 The cumulative irradiation dose is equivalent to the average daily UV exposure of the human body, making the RAUBB data directly relevant to actual use scenarios. The integrated absorbance from 290 to 320 nm was measured sequentially using a micro-UV spectrometer before and after irradiation to calculate the UVB retention rate (RA). UVB ;in,

[0087] The standard O / W sunscreen matrix, calculated by weight percentage, comprises 5.0% glycerin, 3.0% polyglycerol-3-methyl glucoside, 0.5% xanthan gum, and the balance water. The standard O / W matrix (containing emulsifier) ​​is heated in a water bath to 40±1℃ (to avoid high-temperature degradation). 0.5 wt% of the candidate solution is added, and the mixture is homogenized at 15,000 rpm for 3 min, with cooling in an ice bath during the process to avoid localized overheating. After standing for 10 min, centrifugation is performed to remove air bubbles, yielding the emulsified material.

[0088] During coating, weigh the initial weight of the quartz sheet, use an automatic coating machine to evenly coat the emulsified sample, and then immediately weigh the weight after coating and calculate the film thickness: unqualified samples are wiped with ethanol and recoated.

[0089] The detection points are located using laser micro-engraving. Specifically, multiple detection points are laser micro-engraved on a quartz sheet before coating, and the integrated values ​​of 290–320 nm at multiple points are measured before exposure to sunlight, and the average value is taken to obtain the UVB value. 辐照前 UVB levels were obtained by retesting in situ after exposure to sunlight and taking the average value. 辐照后 .

[0090] A5 is based on S=RA UVB ×Fret sorting, outputting the acid substitution type corresponding to the maximum value of S.

[0091] In step A5, the final acid substitution type output by the method is a disulfonic acid group substitution configuration at the 2- and 4-positions of the benzene ring. This configuration was measured to have r = 0.12, Fret = 91.2%, RAUVB = 94.2%, and S = 85.9%, significantly superior to other substitution modes. The sulfonic acid group positions of the raw material were determined by the screening method of claim 7. The 2,4-disulfonic acid configuration naturally prevailed in the S-value ranking due to the ultra-high surface bonding strength of the meta-disulfonic acid on the benzene ring, the photo-oxidation resistance of the sulfonic acid group, and the shielding protection effect on quantum dots, thus verifying the effectiveness of the screening system.

[0092] This invention first reduces the experimental workload by using virtual screening based on pKai and PAR, limiting the number of test samples to less than 50. Then, it rapidly eliminates 50% of strongly adsorbed samples through fluorescence polarization (r value) to avoid interference with subsequent photostability testing. Subsequently, it introduces the quantum dot fluorescence retention rate F... ret UVB retention rate (RA) of sunscreen matrix UVB The product index S is used to simultaneously evaluate the photostability of the molecule itself and its ability to protect photosensitive materials.

[0093] Theoretically, isoamyl 2,4-disulfonic acid cinnamate can achieve better UV protection and water solubility. However, traditional methods result in high impurity rates of disulfonic acid. This embodiment provides a method for synthesizing isoamyl 2,4-disulfonic acid cinnamate, using 4-formyl-1,3-benzenedisulfonic acid, diethyl malonate, and isoamyl alcohol in the presence of catalyst P. Specifically, in this embodiment, catalyst P is 2-carboxy-4-phenylpyrrole, where the carboxyl group stabilizes the transition state through hydrogen bonding, inhibiting the formation of the 2,5-isomer. This method yields isoamyl 2,4-disulfonic acid cinnamate that meets the aforementioned properties, avoiding excessive 2,5-byproducts during atmospheric pressure sulfonation and ensuring a target product purity >98%.

[0094] The synthesis method includes the following steps:

[0095] (a) Diethyl malonate (18.4 g, 0.115 mol) and dry isoamyl alcohol (81 g, 0.920 mol) were mixed and added to a reaction vessel. A 30 wt% KOH / isoamyl alcohol solution (containing 6.44 g, 0.115 mol KOH) was slowly added dropwise at -5 °C. The mixture was stirred at room temperature for 6 hours to generate potassium isoamyl malonate. The process was strictly anhydrous to avoid potassium salt hydrolysis.

[0096] (b) Add glacial acetic acid (6.9 g, 0.115 mol) and stir at 25°C for 2 hours.

[0097] (c) Add 4-formyl-1,3-benzenedisulfonic acid (28.6 g, 0.10 mol) and catalyst P (2-carboxy-4-phenylpyrrole, 1.43 g, 5 wt%), and heat to 130 °C and reflux for 6 h;

[0098] (d) Unreacted isoamyl alcohol was recovered by vacuum distillation at -0.095 MPa, 200 ml of pure water was added, and the mixture was cooled to 5 °C to crystallize. The crystals were then filtered and dried to obtain the target compound, isoamyl 2,4-disulfonic acid cinnamic acid.

[0099] Example 2

[0100] Compared with Example 1, the amount of 4-formyl-1,3-benzenedisulfonic acid used in this example is 25.0g, the amount of diethyl malonate used is 17.6g, and the amount of dried isoamyl alcohol is 77.4g. The rest is the same as in Example 1, and will not be repeated here.

[0101] Example 3

[0102] Compared with Example 1, the amount of 4-formyl-1,3-benzenedisulfonic acid in this example is reduced to 31.8g, the amount of diethyl malonate is 17.6g, and the amount of dried isoamyl alcohol is 77.4g. The rest is the same as in Example 1, and will not be repeated here.

[0103] Example 4

[0104] Compared with Example 1, the amount of 4-formyl-1,3-benzenedisulfonic acid in this example is reduced to 28.6g, the amount of diethyl malonate is 17.6g, and the amount of dried isoamyl alcohol is 77.4g. The rest is the same as in Example 1, and will not be repeated here.

[0105] Example 5

[0106] Compared with Example 1, the amount of 4-formyl-1,3-benzenedisulfonic acid in this example is reduced to 28.6g, the amount of diethyl malonate is 18.4g, and the amount of dried isoamyl alcohol is 70g. The rest is the same as in Example 1, and will not be repeated here.

[0107] Furthermore, Table 3 below shows the performance test data for Examples 1 to 5:

[0108] Table 3

[0109] Example Yield / % r value RAUVB / % Fret / % S value / % 1 86.5 0.12 94.2 91.2 85.9 2 82.3 0.14 92.7 90.1 83.5 3 87.1 0.11 95.0 92.4 87.8 4 84.7 0.13 93.5 90.8 84.9 5 85.2 0.12 94.0 91.0 85.5

[0110] Based on this, Table 4 below shows the raw material variables and performance test data for Comparative Examples 1 to 5:

[0111] Table 4

[0112]

[0113] As shown in the above experiments, Comparative Example 1, due to the lack of catalyst P, resulted in the formation of more than 30% of 2,5-isomers, which disrupted the conjugated planarity and quantum dot binding force, leading to an increase in the r value. Comparative Example 2, using monosulfonic acid as a raw material, weakened the electron-withdrawing effect and water solubility, resulting in a narrowing of the UVB absorption bandwidth. In Comparative Example 3, the accumulation of β-hydroxy intermediates during the reaction at 100℃ and incomplete decarboxylation produced carboxylic acid impurities, triggering fluorescence quenching and reducing Fret. Comparative Example 4, using fuming sulfuric acid sulfonation, caused excessive substitution and carbonization at the 5-position of the benzene ring, resulting in increased photosensitivity and matrix precipitation. In Comparative Example 5, high-temperature crystallization introduced impurities, reducing the dispersibility of quantum dots. All comparative examples showed S < 85.5, verifying the irreplaceable nature of this invention in the UV absorber-quantum dot synergistic system.

[0114] In the method described above, the high selectivity of the 2,4-substituted product stems from the inherent structural characteristics of the starting material 4-formyl-1,3-benzenedisulfonic acid. The two sulfonic acid groups at the 1,3-position significantly reduce the electron density of the benzene ring, making the formyl group (-CHO) at the 4-position the only strongly affinity site. The malonate anion selectively attacks the 4-position to form the 2,4-disulfonic acid product. The intervention of a catalyst further enhances this selectivity by accelerating the reaction and suppressing byproducts. The hydrogen bonding of the pyrrole ring anchors the aldehyde oxygen, ensuring the reaction occurs at the 4-position, ultimately yielding high-purity isoamyl cinnamate 2,4-disulfonic acid.

[0115] The structure of isoamyl cinnamate can absorb ultraviolet light, and the sulfonic acid group provides water solubility. This reaction employs a one-pot synthesis, reducing the difficulty of synthesizing cinnamate esters with strong acids. Furthermore, the catalyst P used possesses excellent catalytic performance, significantly improving the selectivity and conversion rate compared to other catalysts. Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for screening the substitution type of phenyl cyclic acid groups based on isoamyl cinnamate, characterized in that, Includes the following steps: A1 provides CdSe / ZnS core-shell quantum dot probes with surface-modified polyethylene glycol-acrylic acid copolymers; A2 establishes a virtual substituent library by introducing acid substituents onto the benzene ring based on the isoamyl cinnamate core, generating multiple substitution combinations; predicts the minimum acid dissociation constant pKai for each structure, and calculates the polar atom ratio PAR, calculates the product of the absolute values ​​of the two and screens ≤50 candidate structures in descending order. Polar atoms include oxygen, nitrogen, sulfur, and phosphorus; A3 prepared physical compounds according to the candidate structures, and each physical compound was prepared into a 0.1 mg / mL aqueous solution and a 0.1 μM quantum dot probe was added. The fluorescence polarization anisotropy r was measured and the top 50% of the samples were screened in order of increasing r value. A4 samples screened after A3 underwent the following parallel testing: In Group A, the quantum dot solution prepared in A3 was irradiated with UV-B to determine the quantum dot fluorescence intensity retention rate F. ret Group B involved preparing a new, pure sample aqueous solution without quantum dots, adding it at 0.5 wt% to a standard O / W sunscreen matrix, applying it, and then subjecting it to simulated sunlight irradiation to determine the UVB retention rate (RA) of the coating. UVB ; A5 is based on S=RA UVB ×F ret Sort the samples and output the acid substitution type corresponding to the maximum value of S.

2. The method for screening the substitution type of phenyl cyclic acid groups based on isoamyl cinnamate according to claim 1, characterized in that, In step A1, in the polyethylene glycol-acrylic acid copolymer modification of the quantum dot probe, the molar ratio of polyethylene glycol to acrylic acid is 1:95~105; the CdSe core diameter of the quantum dot probe is 4.5±0.5nm, and the ZnS shell thickness is 1.0±0.2nm.

3. The method for screening the substitution type of phenyl cyclic acid groups based on isoamyl cinnamate according to claim 1, characterized in that, Step A2 includes: The structure of isoamyl cinnamate was loaded into cheminformatics software, and the 2, 3, 4, 5, and 6 positions of the benzene ring were identified as substitution sites. Based on the isoamyl cinnamate core, acid substituents are introduced at the substitution sites to generate all possible single / double substitution combinations; Predict the acid dissociation constants of all acid substituents in each structure, and denote the minimum value as pKai; eliminate structures where |pKai|>4; Calculate the polar atom ratio PAR, where PAR = number of polar atoms / total number of atoms.

4. The method for screening the substitution type of phenyl cyclic acid groups based on isoamyl cinnamate according to claim 3, characterized in that, In step A2, the acid substituents include at least sulfonic acid group, carboxyl group, phosphoric acid group, phosphonic acid group, sulfonamide group, oxalyl group and their ionized forms.

5. The method for screening the substitution type of phenyl cyclic acid groups based on isoamyl cinnamate according to claim 1, characterized in that, In step A3, during fluorescence polarization measurement, the excitation wavelength is 365±5nm and the emission wavelength is 610±5nm. The formula for calculating the fluorescence polarization anisotropy value r is as follows: ； Where I1 is the intensity of vertically polarized light and I2 is the intensity of parallelly polarized light.

6. The method for screening the substitution type of phenyl cyclic acid groups based on isoamyl cinnamate according to claim 1, characterized in that, In step A4, The dominant wavelength of UV-B irradiation in Group A was 311±2 nm, and the irradiation intensity was 0.50±0.05 mW / cm². 2 The cumulative irradiation time was 120±5 min. The fluorescence intensity of the quantum dots was measured before and after irradiation, and the fluorescence intensity retention rate F of the quantum dots was determined. ret =(F 辐照后 / F 辐照前 ) × 100%.

7. The method for screening the substitution type of phenyl cyclic acid groups based on isoamyl cinnamate according to claim 1, characterized in that, In step A4, The B group test involved adding a newly prepared pure sample aqueous solution to a standard O / W sunscreen matrix, homogenizing it, and then coating it onto a quartz plate for cumulative 30.0 ± 0.5 kJ / m² testing. 2 Irradiation was performed, and the integrated absorbance at 290–320 nm was measured sequentially before and after irradiation. The UVB retention rate RA was then calculated. UVB Among them, RA UVB = (UVB 辐照后 / UVB 辐照前 ) × 100%.

8. The method for screening the substitution type of phenyl cyclic acid groups based on isoamyl cinnamate according to claim 1, characterized in that, In step A5, the final acid substitution type output by the method is a disulfonic acid substitution configuration at the 2- and 4-positions of the benzene ring.

9. An isoamyl 2,4-disulfonic acid cinnamate obtained by the screening method of claim 8, characterized in that, Used in UV protectants and sunscreens.

10. A method for synthesizing isoamyl 2,4-disulfonic acid cinnamic acid ester as described in claim 9, characterized in that, It was prepared by reacting 4-formyl-1,3-benzenedisulfonic acid, diethyl malonate and isoamyl alcohol in the presence of catalyst P. Catalyst P is R1 is an alkyl group, and R2 is an aromatic group.

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