Isoamyl cinnamate-based benzene ring acid group substitution type screening method and application thereof

Abstract

The invention relates to the technical field of component design, in particular to a benzene ring acid group substitution type screening method based on isoamyl cinnamate and application of the benzene ring acid group substitution type screening method based on isoamyl cinnamate. The screening method comprises the steps that a virtual substituent library is established, acid group substituents are introduced to an isoamyl cinnamate benzene ring, and a plurality of substitution combinations are generated; predicting a minimum value pKai of an acid dissociation constant and a polar atom ratio PAR for each structure, and screening less than or equal to 50 candidate structures according to the minimum value pKai and the polar atom ratio PAR; measuring the fluorescence polarization anisotropy r of each candidate structure, and screening the first 50% of samples according to the sequence of r values from small to large; sequentially measuring the quantum dot fluorescence intensity retention rate Fret and the coating UVB retention rate RAUVB of the screened samples; and outputting the acid group substitution type corresponding to the maximum value according to the product sequence of the two. The self anti-ultraviolet attenuation capability and the photosensitive component protection effect are reflected, and the optimal structure is ensured to have self stability and synergistic protection performance in a real compound system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of component design, in particular to a screening method for benzene ring acid group substitution type based on isoamyl cinnamate and application thereof. BACKGROUND

[0002] Currently, isoamyl cinnamate derivatives have become the mainstream research object of high-efficiency anti-ultraviolet additives due to their significant ultraviolet absorption characteristics. In the molecular design of light-stable additives, acid group functional modification is considered as a key path to improve water solubility and emulsification efficiency, and therefore, benzene ring acid group substitution based on isoamyl cinnamate has become the main way to improve its performance.

[0003] However, the existing screening system is limited to static evaluation, and it is difficult to directly characterize the gain mechanism of the acid group polarity network to the interface anchoring by evaluating single-point parameters. For example, the QSAR model based on quantum chemical calculation can quickly predict the liposolubility (LogP) and molar absorption coefficient of molecules. This method can complete the theoretical evaluation of thousands of structures within a few hours, greatly reducing the initial research and development cost. However, it can only predict the properties of the molecule itself, such as UV absorption intensity, and completely ignores its protection efficiency for other photosensitive components (such as vitamin C) in the formula. Pseudo-high-score molecules fail to protect photosensitive materials in the complex system. Experimental testing can reflect the performance of the complex system, but it cannot distinguish the independent contribution of the stability of the molecule itself and the protection ability of the material. Moreover, only experimental testing requires the synthesis of physical compounds, resulting in excessive consumption of research and development resources on low-potential molecules. The essence of this contradiction is that anti-ultraviolet additives need to simultaneously bear the functions of self-light stability and external protection efficiency in real application scenarios, but the existing technology lacks a simultaneous quantitative mechanism for the synergistic mechanism of the two performances. This leads to repeated failures in selecting structures, which has become a technical bottleneck that the industry has not broken through for a long time.

[0004] The information disclosed in this BACKGROUND section is only intended to enhance the understanding of the general background of the application and should not be taken as an acknowledgement or any form of suggestion that this information constitutes prior art. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a screening method for benzene ring acid group substitution type based on isoamyl cinnamate, to obtain a structure with excellent performance, and to solve the problem of low development efficiency of anti-ultraviolet additives caused by the inability of the prior art to balance the self-light stability and the protection efficiency of photosensitive materials.

[0006] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is:

[0007] A screening method for benzene ring acid group substitution type based on isoamyl cinnamate, comprising the following steps:

[0008] A1 provides a CdSe / ZnS core-shell quantum dot probe with surface modification of polyethylene glycol-acrylic acid copolymer;

[0009] A2 establishes a virtual substituent library, introduces acid group substituents on the benzene ring of the cinnamyl acetate nucleus to generate multiple substitution combinations; for each structure, the minimum acid dissociation constant pKai is predicted, and the polar atom ratio PAR is calculated, the absolute value of the product of the two is calculated and screened in descending order ≤50 candidate structures;

[0010] The 50 candidate structures reserved all meet the ionizable performance requirements and have weak / medium binding force, which can be adapted to the fluorescence polarization detection of A3 step and avoid shielding the surface of the quantum dots in A4.

[0011] A3 prepares each candidate structure into a 0.1 mg / mL aqueous solution and adds 0.1 μM quantum dot probes, measures the fluorescence polarization anisotropy r and screens the top 50% samples in descending order; in actual implementation, the product of the absolute values of pKai and PAR can be verified in descending order in batches, wherein if the total number of samples ≤10, at least the top 5 are screened. The reason for this test is that the quantum dots with unshielded surface can effectively disperse ultraviolet energy (Fret≥92%), and strong adsorbed molecules will form a "dead layer", which will instead cause the SPF value to decay. The CdSe / ZnS quantum dots modified by PEG-acrylic acid copolymer are used for cinnamic acid ester derivative screening in the present application, and the fluorescence signal amplification and polarization response characteristics are used to realize rapid binding capacity evaluation.

[0012] A4 performs the following parallel detection on the samples screened in A3: wherein group A detection is to measure the fluorescence intensity retention rate F ret of the quantum dots in the quantum dot solution prepared in A3 under UV-B irradiation, to characterize the molecular photoprotective ability; group B detection is to re-prepare a pure sample aqueous solution without quantum dots, add 0.5wt% to a standard O / W sunscreen base, and after coating, measure the UVB retention rate RA UVB of the coating under simulated sunlight irradiation.

[0013] A5 sorts according to S = RA UVB × F ret , and outputs the acid group substitution type corresponding to the maximum S value.

[0014] As preferred, in step A1, the polyethylene glycol-acrylic acid copolymer modification can improve the water solubility and biocompatibility of the quantum dots, and 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 surface carboxyl density is ensured, which is beneficial to the interaction with the acid group substituent, the diameter of the CdSe core of the quantum dot probe is 4.5±0.5 nm, and the thickness of the ZnS shell layer is 1.0±0.2 nm, so as to provide a stable fluorescence signal and meet the requirements of fluorescence polarization detection.

[0015] As preferred, step A2 eliminates systematic bias by calculating regular reconstruction, specifically including:

[0016] Load the structure of isoamyl cinnamate in a chemical informatics software such as ChemAxon or RDKit, and define the benzene ring 2, 3, 4, 5, and 6 positions as substitution sites;

[0017] Based on the isoamyl cinnamate nucleus, introduce acid group substituents at the substitution sites to generate all possible single / double substitution combinations; specifically, single substitution is to independently introduce acid group substituents at each site, and double substitution is a non-adjacent combination, this step excludes adjacent steric hindrance conflict combinations and triple substitution combinations to avoid steric hindrance interference with subsequent detection;

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

[0019] Calculate the polar atom ratio PAR, where the polar atom ratio PAR = the number of polar atoms / the total number of atoms, and the polar atoms include oxygen, nitrogen, sulfur, and phosphorus, where the number of polar atoms PAC = aN O +bN N +cN S +dN P , N O , N N , N S , N P are the number of oxygen, nitrogen, sulfur, and phosphorus atoms in the molecule. a, b, c, and d are correction coefficients, which are calibrated based on atomic polarizability, and preferably a=1, b=1.2, c=2, and d=3. The correction coefficients strengthen the contribution weight of sulfur / phosphorus atoms to the polarity of the molecule, highlight the high coordination ability of sulfonic acid groups / phosphonic acid groups, and suppress the false high score of weak acid molecules containing multiple oxygen atoms (such as boric acid), thereby improving the discrimination sensitivity of strong acid structures. The purpose of the acid and polarity preliminary screening in the present application is that the synergy of strong acid and high polarity can improve the water solubility and realize the potential of high surface activity.

[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 preferred,

[0029] The standard O / W sunscreen base comprises glycerin 5.0%, polyglyceryl-3 methylglucoside 3.0%, xanthan gum 0.5%, and the balance water, calculated as a percentage by mass;

[0030] The coating film thickness is 2.0±0.2 mg / cm 2 ; irradiation is performed using a xenon lamp weatherometer.

[0031] The detection points are located by laser micro-etching marking. Specifically, before coating, multiple detection points of the quartz piece are marked by laser micro-etching, the integral values of 290-320 nm of the multiple points are measured before exposure and the average value is obtained as UVB 辐照前 , and the multiple points are re-measured in situ after exposure and the average value is obtained as UVB 辐照后 .

[0032] As preferred, in step A5, the present application is sorted and the maximum value of S is outputted according to S=RA UVB ×F ret , which is used to quantify the dual function of the sunscreen agent, and the position of the sulfonic acid group of the raw material is determined by the screening method. The final output of the acid group substitution type is the double sulfonic acid group substitution configuration of the benzene ring 2 and 4 positions. This configuration naturally wins in the S value sorting by virtue of the ultra-high surface binding strength of the benzene ring meta double sulfonic acid, the light oxidation resistance of the sulfonic acid group, and the shielding protection effect on quantum dots, verifying the effectiveness of the screening system.

[0033] This configuration simultaneously realizes its own high light stability and strong protection of light-sensitive components. The strong electron-withdrawing effect of the benzene ring 2,4-position double sulfonic acid group forms a D-π-A structure with the conjugated bond of cinnamic acid olefin, significantly reduces the π-π* transition energy level, and accurately red shifts the maximum absorption wavelength to the core waveband of UV-B; the symmetrical substitution of double sulfonic acid maintains the conjugation planarity, avoids steric hindrance, enhances water solubility through sulfonic acid group ionization, and cooperates with n-π transition to form a wide spectrum of 280-320 nm absorption, greatly improving the ultraviolet coverage efficiency. The meta double sulfonic acid substitution stabilizes the conjugated system through intramolecular hydrogen bond network, endows excellent light decomposition resistance, and still maintains high-efficiency ultraviolet shielding function under long-term sunlight exposure, persistently blocks the damage of UVB to the skin. The non-planar adsorption characteristics make it only produce weak bonding when protecting light-sensitive components, perfectly balance its own light stability and light-sensitive material protection efficiency, and fundamentally solve the problem of optical material failure caused by strong shielding effect of traditional sunscreen agents.

[0034] The strong hydrophilicity of the double sulfonic group makes it have high solubility in an aqueous system, avoids the problem that a large amount of surfactant needs to be used for solubilization of a traditional oil-soluble sunscreen agent, the ionization characteristic enables it to be well compatible with various sunscreen bases (O / W, W / O, silicone oil-based, etc.), the formulation adaptability is wide, the synergistic effect of the intramolecular hydrogen bond network and the conjugated system enables it to remain stable in a high-temperature and high-humidity environment, the sweat resistance performance is outstanding, and the sunscreen active ingredient can be used as a high-efficiency sunscreen active ingredient and can be further applied to the field of functional products such as anti-photoaging cosmetics.

[0035] A second object of the present application is to provide the 2,4-disulfonic cinnamic acid isoamyl ester obtained by the above screening method, which is used in anti-ultraviolet agents and sunscreens, and synchronously quantifies the photostability of the molecule itself and the exogenous protection efficiency.

[0036] In order to achieve the above object, the technical scheme adopted by the present application is:

[0037] A method for synthesizing 2,4-disulfonic cinnamic acid isoamyl ester, which is prepared by reacting 4-formyl-1,3-benzenedisulfonic acid, malonic acid diethyl ester and isoamyl alcohol under the catalysis of a catalyst P;

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

[0039] The present application uses 4-formyl-1,3-benzenedisulfonic acid as a key raw material, uses the strong electron-withdrawing effect and steric hindering effect of the double sulfonic group at the 1,3-position to ensure that the reaction occurs on the 4-position aldehyde group, so that the regioselectivity of the product 2,4-disulfonic configuration is as high as more than 99%, and the problem of impurities such as 2,5-isomer produced by the traditional sulfonation method is fundamentally avoided. Secondly, the pyrrole derivative catalyst is innovatively introduced, the steric hindering of the pyrrole ring further inhibits the side reaction, the yield of the condensation reaction is improved, the fluorescence polarization r value of the obtained product and the comprehensive performance score S all meet the requirements, and the product has excellent ultraviolet absorption capacity and quantum dot protection function. The method is high in atom economy, green and environmentally friendly, and provides a key raw material guarantee for the development of new sunscreen materials.

[0040] The reaction equation is as follows:

[0041]

[0042] The synthesis method of the present application prepares the 2,4-disulfonic cinnamic acid isoamyl ester meeting the above performance, avoids the over-standard 2,5-by-product in the atmospheric sulfonation method, and ensures that the purity of the target product is greater than 98%.

[0043] As preferred, the synthesis method comprises the following steps:

[0044] (a) Put malonic acid diethyl ester and dry isoamyl alcohol into a reaction kettle, slowly drop potassium hydroxide isoamyl alcohol solution at -5 DEG C, stir at room temperature for 4-8 hours to generate isoamyl alcohol potassium malonate;

[0045] (b) Add glacial acetic acid with potassium hydroxide in equimolar amount to neutralize excess KOH, avoid aldehyde group condensation out of control in strong alkali environment, control temperature ≤ 30 DEG C, stir for 1-3 hours;

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

[0047] (d) Recover unreacted isoamyl alcohol by vacuum rectification under -0.095 MPa, add 2-5 times volume of pure water to cool to 0-10 DEG C to obtain target compound 2, 4-di sulfonic acid isoamyl cinnamate.

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

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

[0050] The reaction is synthesized by one-pot method, which reduces the difficulty of synthesis of strong acid substituted cinnamate ester. 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 the present application are:

[0052] The present application avoids the waste of resources caused by traditional blind synthesis by calculating the minimum acid dissociation constant pKai and the proportion of polar atoms PAR, and calculating the product of the absolute values of the two, and screening ≤50 candidate structures in descending order. Then, through quantum dot probe fluorescence polarization, the binding affinity of sunscreen and photosensitive material is quantified in real time, solving the core defect that traditional virtual screening cannot predict the protection efficiency of molecules; then, through double light stability detection, RA UVB and F ret are output synchronously, which reflects the anti-ultraviolet attenuation ability and photosensitive component protection effect, and the mathematical coupling of the dual functions realizes the dual functions, ensuring that the preferred structure has both stability and synergistic protection in the real complex system.

[0053] The present application is screened by the above-mentioned screening method, and the acid group substitution type is a double sulfonic acid group substitution configuration of the 2nd and 4th positions of a benzene ring, wherein the A group detection is verified by a quantum dot probe to verify the light protection ability, and the quantum dot fluorescence retention rate Fret is greater than or equal to 95% after irradiation, proving the high-efficiency ultraviolet filtering ability. The B group detection tests the long-term stability in a sunscreen base, and the double sulfonic acid group substitution improves the molecular polarity, is oriented to the oil-water interface in the O / W sunscreen base, the hydrophilic sulfonic acid group is anchored in the water phase, the hydrophobic isoamyl ester chain is inserted into the oil phase, a molecular-level ultraviolet shielding film is formed, and breakthrough advantages are exhibited in ultraviolet absorption characteristics and sunscreen effect. BRIEF DESCRIPTION OF DRAWINGS

[0054] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0055] Figure 1 The step flow chart of the screening method of the present application. DETAILED DESCRIPTION

[0056] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, 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 application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0058] Embodiment 1

[0059] As Figure 1 shown, the present embodiment provides a screening method of benzene ring acid group substitution type based on isoamyl cinnamate, comprising the following steps:

[0060] A1 provides a CdSe / ZnS core-shell quantum dot probe of surface modified polyethylene glycol-acrylic acid copolymer;

[0061] The polyethylene glycol-acrylic acid copolymer modification can improve the water solubility and biocompatibility of the 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; the surface carboxyl density is ensured, which is beneficial to the interaction with the acid group substituent, the diameter of the CdSe core of the quantum dot probe is 4.5±0.5 nm, and the thickness of the ZnS shell layer is 1.0±0.2 nm, 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 are added to a reaction kettle, oxygen is removed by nitrogen, 0.1 mmol of AIBN is added, and the reaction is carried out at 70°C for 24 hours to obtain a copolymer with a PEG:acrylic acid molar ratio of 1:100. The copolymer is dissolved in chloroform at 10 mg / mL, and the CdSe / ZnS quantum dot solution is added according to the molar ratio of quantum dot surface area to copolymer carboxyl group of 1:500. The mixture is oscillated in a 40°C water bath for 12 hours. Free polymer is removed by ultracentrifugation, and the precipitate is resuspended in ultrapure water to obtain the product, which is stored at 4°C in the dark.

[0063] A2 establishes a virtual substituent library, introduces acid group substituents on the benzene ring of the cinnamyl acetate nucleus to generate multiple substitution combinations, predicts the minimum acid dissociation constant pKai for each structure, 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 bias by calculation rules, specifically including:

[0065] The cinnamyl acetate structure is loaded in a chemical informatics software such as ChemAxon or RDKit, and the benzene ring 2, 3, 4, 5, and 6 positions are defined as substitution sites; acid group substituents such as sulfonic acid group, carboxyl group, phosphoric acid group, phosphonic acid group, sulfonamide group, oxalyl group and ionized forms thereof are introduced on the substitution sites to generate all possible single / double substitution combinations;

[0066] Specifically in the present embodiment, isovaleric acid (CC(C)CCOC(=O)C=C1=C1=C1=C1) is loaded in ChemAxon JChem, and the benzene ring substitution site is locked. The acid group is input to perform single substitution or double substitution, wherein the single substitution is to replace one H, and the double substitution is to replace two non-adjacent Hs. This step excludes adjacent steric hindrance conflict combinations and triple substitution combinations to avoid steric hindrance interference with subsequent detection; pKai prediction is performed by ChemAxon pKa Plugin (v22.15), and the parameter is set to a temperature of 25.0 °C, an ionic strength of 0.15 M, an environmental pH of 7.4, interconversion isomer analysis is enabled, and the minimum value of all acid group dissociation constants is taken as pKai. Among them, the electronic effect and steric hindrance between the double acid groups will cause significant deviation. The acid group of the double substitution is parameter-modified in the process, as shown in Table 1 below:

[0067] Table 1

[0068] Acid group type Correction value Sulfo group -0.30 Carboxylic group +0.20 Phospho group +0.10 Phosphonic group -0.45 Sulfonamide group +1.20 Oxalyl group +0.35

[0069] The correction value is obtained based on experience, and part of the data verification is shown in Table 2 below:

[0070] Table 2

[0071] Molecular structure Predicted pKai (uncorrected) Corrected pKai Experimental value 2-sulfo-4-carboxylic group -1.85 -1.65 -1.62 4-phospho-2-sulfonamide group -0.92 -1.37 -1.40 3-oxalyl-5-sulfo group -2.30 -1.95 -1.98

[0072] This step screens structures with |pKa|≤4 to ensure that the substituent can be ionized at physiological pH and enhance the interaction with quantum dots.

[0073] The polar atom ratio PAR is calculated, wherein the polar atom ratio PAR = the number of polar atoms / the total number of atoms, and the polar atoms include oxygen, nitrogen, sulfur, and phosphorus, wherein the number of polar atoms PAC = aN O +bN N +cN S +dN P , N O , N N , N S , N P are the numbers of oxygen, nitrogen, sulfur, and phosphorus atoms in the molecule, respectively. a, b, c, and d are correction coefficients, which are calibrated based on atomic polarizability, for example, preferably a = 1, b = 1.2, c = 2, and d = 3. The correction coefficients strengthen the contribution weight of sulfur / phosphorus atoms to the polarity of the molecule, highlight the high coordination ability of the sulfonic acid group / phosphonic acid group, and suppress the false high score of weak acid molecules containing multiple oxygen atoms (such as boric acid), thereby improving the discrimination sensitivity to strong acid structures. The purpose of the acid and polarity preliminary screening in the present application is that the synergy of strong acid and high polarity can improve water solubility and realize high surface activity potential.

[0074] Then the product of the absolute values of both is calculated and the ≤50 candidate structures are sorted in descending order. The 50 candidate structures that are retained all meet the ionizable performance requirement and have weak / moderate binding, which can adapt to the fluorescence polarization detection of A3 and avoid shielding the surface of the quantum dots in A4. In this step, the TOP 10 representative structures include: bis-sulfonic acid groups, sulfonic acid-phosphonic acid groups, sulfonic acid-oxalyl groups, sulfonic acid-carboxylic acid groups, sulfonic acid-carboxylic acid groups, sulfonamide-sulfonic acid groups, phosphonic acid-oxalyl groups, sulfonic acid-phosphoric acid groups, carboxylic acid-oxalyl groups, bis-phosphonic acid groups, sulfonic acid (single substitution).

[0075] A3, each candidate structure is sequentially prepared into a 0.1 mg / mL ultrapure water solution and 0.1 μM quantum dot probes are added, the fluorescence polarization anisotropy r is measured, and the top 50% samples are sorted in descending order. In actual implementation, the product of the absolute values of pKai and PAR can be used for batch verification in descending order, and if the total number of samples ≤10, at least the top 5 are sorted.

[0076] Specifically, 96-well plate high-throughput screening is used, 80 μL of the solution is added to a black 96-well plate, 20 μL of 0.5 μM quantum dot probes (final concentration 0.1 μM) is added to each well, and the PerkinElmer EnVision multi-mode plate reader is used to measure the vertical polarization light intensity (I1) and the parallel polarization light intensity (I2) at an excitation wavelength of 365 nm and an emission wavelength of 610 nm to calculate the fluorescence polarization anisotropy value r. The calculation formula of the fluorescence polarization anisotropy value r is:

[0077]

[0078] Wherein, I1 is the vertical polarization light intensity, and I2 is the parallel polarization light intensity. The fluorescence polarization anisotropy value is used to quantify the orientation order of the fluorescent molecules under the excitation of polarized light, and reflects the molecular rotation freedom or the binding state with the surrounding environment. In the present application, the strength of the molecule-nanoparticle interaction is judged by the change in r value, and preferably, r ≤ 0.15, at which time the molecule has moderate binding with the quantum dots and does not shield the surface active sites thereof. The reason why the present application carries out this test is that the quantum dots with unshielded surfaces can effectively disperse ultraviolet energy (F ret ≥92%) and strong adsorbing molecules form a "dead layer", which instead causes the SPF value to decay. And weak binding improves the potential matching with sunscreen bases and avoids flocculation.

[0079] The present application can complete the quantum dot protection performance evaluation of 50 candidate molecules within 72 hours, and the data dispersion RSD is less than 6%. The material of the 96-well plate is black polypropylene, the optical transmittance of the well bottom is greater than 90%, the liquid volume of each well is 100±2 μL, and each plate contains 4 well blank controls (only quantum dot solution) + 4 well standard controls (0.1 mM octocrylene). Specifically, when measuring fluorescence polarization, the excitation wavelength is 365±5 nm, covering the π-π* transition absorption peak of cinnamate, avoiding interference peaks, the emission wavelength is 610±5 nm, matching the maximum emission wavelength of quantum dots, and eliminating signal attenuation caused by Stokes shift,

[0080] A4 performs the following parallel detection on the samples screened from A3: the A group detection is to take the quantum dot solution configured in A3 to perform UV-B irradiation, measure the fluorescence intensity retention rate Fret of the quantum dots, and characterize the molecular light protection ability; the B group detection is to reconfigure a pure sample aqueous solution without quantum dots, add 0.5wt% to the standard O / W sunscreen base, coat it, and then measure the UVB retention rate RA of the coating after simulated sunlight irradiation UVB ;

[0081] In step A4,

[0082] The A group detection is:

[0083] Take the quantum dot solution configured in A3, dilute it to 50nM with PBS buffer solution with pH 7.4. After vortexing at 800 rpm in the dark for 30 s, stand for 15 min to ensure uniform dispersion of the complex. Then load the 96-well plate, add 100 μL of quantum dot solution to each well, and set up duplicate wells (n=6). Set up non-complexed quantum dot solution and PBS buffer as control tests.

[0084] Before irradiation, measure the fluorescence intensity of the quantum dots with an EnVision plate reader; place the 96-well plate in a UV-B irradiation instrument for UV-B irradiation, the main wavelength of the UV-B irradiation is 311±2 nm, the irradiation intensity is 0.50±0.05 mW / cm 2 , and the cumulative time is 120±5 min, to accurately simulate the peak value of the sunlight spectrum and avoid false negatives caused by overexposure. Monitor the plate temperature with an infrared thermal imager during the process, and start the cooling fan when the temperature exceeds 28℃ to avoid thermal quenching; measure the fluorescence intensity of the quantum dots with an EnVision plate reader within 10 min after irradiation; finally, calculate the fluorescence intensity retention rate F ret of the quantum dots = (F 辐照后 / F 辐照前 )×100%;

[0085] The B group detection is:

[0086] The reconstituted pure sample aqueous solution was added to the standard O / W sunscreen base at 0.5wt% and homogenized, coated on laser micro-etched quartz slides, and the coating film thickness was 2.0±0.2mg / cm 2 Then, a xenon lamp weatherometer was used for cumulative irradiation of 30.0±0.5kJ / m 2 The cumulative irradiation dose of 30.0±0.5kJ / m 2 was equivalent to the average daily UV exposure of the human body, so that the RAUVB data was directly related to the actual use scenario. Before and after irradiation, the integral absorbance of 290-320nm was measured in turn by a micro-UV spectrometer, and the UVB retention rate RA UVB was calculated; wherein,

[0087] The standard O / W sunscreen base included glycerin 5.0%, polyglyceryl-3 methylglucose distearate 3.0%, xanthan gum 0.5%, and the balance water, calculated as a percentage by mass; the standard O / W base (containing emulsifiers) was heated in a water bath to 40±1℃ (to avoid high-temperature degradation). The candidate solution was added at 0.5wt%, and the homogenizer was emulsified at 15,000rpm for 3min, with ice bath cooling during the process to avoid local overheating. After standing for 10min, the bubbles were removed by centrifugation to obtain the emulsified material.

[0088] During coating, the initial weight of the quartz slide was weighed, the emulsified sample was uniformly coated using an automatic coating machine, and then the weight after coating was immediately weighed and the film thickness was calculated: unqualified samples were re-coated after being wiped with ethanol.

[0089] The detection points were located by laser micro-etching marking. Specifically, before coating, the quartz slide was laser micro-etched and marked at multiple detection points, the integral values of 290-320nm at the multiple points were measured before exposure and the average value was taken to obtain UVB 辐照前 , and after exposure, the multiple points were re-measured in situ and the average value was taken to obtain UVB 辐照后 .

[0090] A5 was sorted according to S=RA UVB ×Fret, and the acid group substitution type corresponding to the maximum S value was output.

[0091] In step A5, the acid group substitution type finally output by the method was a 2,4-disulfonic acid substitution configuration of the benzene ring. The configuration had r=0.12, Fret=91.2%, RAUVB=94.2%, S=85.9%, and was significantly better than other substitution modes. The position of the sulfonic acid group of the raw material was determined by the screening method of claim 7. The 2,4-disulfonic acid configuration naturally won in the S value sorting by virtue of the ultrahigh surface binding strength of the benzene ring meta-disulfonic acid, the light oxidation resistance of the sulfonic acid group, and the shielding protection effect on the quantum dots, verifying the effectiveness of the screening system.

[0092] The present application is first based on the virtual screening of pKai and PAR, reducing the experimental amount, controlling the to-be-tested sample to within 50 groups, then quickly eliminating 50% strong adsorption samples through fluorescence polarization (r value) to avoid interference with subsequent light stability test. Then the quantum dot fluorescence retention rate F ret The product of the multiplication of the sunscreen base UVB retention rate RA UVB and the multiplication index S of the UVB retention rate of the sunscreen base, the light stability of the molecule itself and the protection ability of the light-sensitive material are synchronously evaluated.

[0093] 2,4-diisopentyl cinnamate can theoretically achieve better anti-ultraviolet effect and water solubility, but the impurity rate of the double sulfonic acid synthesized by the traditional method is high, and the embodiment provides a method for synthesizing 2,4-diisopentyl cinnamate. 4-formyl-1,3-benzenedisulfonic acid, malonic acid diethyl ester and isoamyl alcohol are reacted under the catalysis of catalyst P to obtain; in the embodiment, the catalyst P is 2-carboxyl-4-phenylpyrrole, the carboxyl stabilizes the transition state through hydrogen bond, and the generation of 2,5-isomer is inhibited. The synthesis method of the present application can obtain 2,4-diisopentyl cinnamate meeting the above performance, avoid the 2,5-by-product exceeding the standard in the normal pressure sulfonation method, and ensure the purity of the target product > 98%.

[0094] The synthesis method comprises the following steps:

[0095] (a) malonic acid diethyl ester (18.4g, 0.115mol) and dry isoamyl alcohol (81g, 0.920mol) are mixed and added to a reaction kettle, a 30wt% KOH / isoamyl alcohol solution (containing KOH 6.44g, 0.115mol) is slowly added dropwise at-5℃, and stirring reaction is carried out at room temperature for 6h to generate isoamyl potassium malonate; the process is strictly water-free to avoid hydrolysis of potassium salt.

[0096] (b) glacial acetic acid (6.9g, 0.115mol) is added, and stirring is carried out at 25℃ for 2h;

[0097] (c) 4-formyl-1,3-benzenedisulfonic acid (28.6g, 0.10mol) and catalyst P (2-carboxyl-4-phenylpyrrole, 1.43g, 5wt%) are added, heated to 130℃ and refluxed for 6h;

[0098] (d) the unreacted isoamyl alcohol is recovered by reduced pressure rectification at-0.095MPa, 200ml of pure water is added, cooled to 5℃ for crystallization, filtered and dried to obtain the target compound 2,4-diisopentyl cinnamate.

[0099] Example 2

[0100] Compared with Example 1, the amount of 4-formyl-1,3-benzenedisulfonic acid is 25.0 g, the amount of diethyl malonate is 17.6 g, the amount of dry isoamyl alcohol is 77.4 g, and the other conditions are the same as those in Example 1, which are not repeated here.

[0101] Example 3

[0102] Compared with Example 1, the amount of 4-formyl-1,3-benzenedisulfonic acid is reduced to 31.8 g, the amount of diethyl malonate is 17.6 g, the amount of dry isoamyl alcohol is 77.4 g, and the other conditions are the same as those in Example 1, which are not repeated here.

[0103] Example 4

[0104] Compared with Example 1, the amount of 4-formyl-1,3-benzenedisulfonic acid is reduced to 28.6 g, the amount of diethyl malonate is 17.6 g, the amount of dry isoamyl alcohol is 77.4 g, and the other conditions are the same as those in Example 1, which are not repeated here.

[0105] Example 5

[0106] Compared with Example 1, the amount of 4-formyl-1,3-benzenedisulfonic acid is reduced to 28.6 g, the amount of diethyl malonate is 18.4 g, the amount of dry isoamyl alcohol is 70 g, and the other conditions are the same as those in Example 1, which are not repeated here.

[0107] Further, the performance test data of Examples 1 to 5 are shown in Table 3 as follows:

[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] On this basis, the raw material variables and performance test data of Comparative Examples 1 to 5 are shown in Table 4 as follows:

[0111] Table 4

[0112]

[0113] As can be seen from the above experiments, in Comparative Example 1, more than 30% of 2,5-isomers are generated due to the absence of catalyst P, which destroys the conjugate plane and the binding force of quantum dots, resulting in an increase in r value; in Comparative Example 2, the use of a single sulfonic acid raw material weakens the electron-withdrawing effect and water solubility, resulting in a narrowing of the UVB absorption bandwidth; in Comparative Example 3, β-hydroxyl intermediates accumulate at 100°C, and decarboxylation is not complete, producing carboxylic acid impurities, which causes fluorescence quenching and reduces Fret; in Comparative Example 4, sulfonation with fuming sulfuric acid causes excessive substitution and carbonization at the 5-position of the benzene ring, resulting in increased photosensitivity and matrix precipitation; and in Comparative Example 5, high-temperature crystallization introduces impurities, reducing the dispersibility of quantum dots. All of the above comparative examples have S < 85.5, verifying the irreplaceability of the present application in the ultraviolet absorber-quantum dot synergistic system.

[0114] The high selectivity of the 2,4-substituted product in the above-mentioned method is derived from the inherent structural characteristics of the raw 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 strong electrophilic site. The malonic ester anion selectively attacks the 4-position, forming the 2,4-disulfonic acid product. The intervention of the catalyst further enhances this selectivity by accelerating the reaction and inhibiting the formation of by-products. The hydrogen bonding of the pyrrole ring can anchor the aldehyde oxygen, ensuring that the reaction occurs at the 4-position, ultimately obtaining high-purity 2,4-disulfonic acid cinnamyl isopentyl ester.

[0115] The structure of cinnamyl isopentyl ester can absorb ultraviolet light, and the sulfonic acid group can provide water solubility. This reaction uses a one-pot synthesis, reducing the difficulty of synthesizing strong acid-substituted cinnamic esters. In addition, the catalyst P used has excellent catalytic effect, greatly improving the selectivity and conversion rate of the reaction. Those skilled in the art should understand that the present application is not limited by the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application 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. A3 prepared each candidate structure into a 0.1 mg / mL aqueous solution and added 0.1 μM quantum dot probes. 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, and polar atoms include oxygen, nitrogen, sulfur, and phosphorus.

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, The catalyst P was prepared by reacting 4-formyl-1,3-benzenedisulfonic acid, diethyl malonate, and isoamyl alcohol in the presence of catalyst P. R1 is an alkyl group, and R2 is an aromatic group.

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