Preparation methods and applications of a class of bis(trichloromethyl)S-triazine compounds

Abstract

This invention belongs to the field of organic chemistry, specifically relating to a method for preparing and applying a class of bis(trichloromethyl)S-triazine compounds. The method provides that benzonitrile compounds are used as starting materials, undergoing a cyclotrimerization reaction with trichloroacetonitrile, followed by a Knevengel reaction with benzaldehyde compounds to obtain bis(trichloromethyl)S-triazine compounds. The preparation method of this invention is simple, with easily controllable temperature and few impurities throughout the process; it significantly reduces costs and greatly improves purity and yield, achieving purities >99% and yields >70%; the products have good solubility; more importantly, almost all compounds exhibit more active inhibitory effects on HepG2 human liver cancer cells than the control cisplatin; making these compounds not only suitable as photochemical agents in the chemical industry but also beneficial for screening tumor therapeutic drugs.

Description

Technical Field

[0001] This invention belongs to the field of organic chemistry technology, and specifically relates to a method for preparing a class of bis(trichloromethyl)S-triazine compounds, as well as the use of such compounds in inhibiting tumor cells. Background Technology

[0002] S-triazine derivatives, due to the substitution of three hydrocarbon groups in their benzene ring with nitrogen atoms and the presence of three easily modifiable sites at positions 2, 4, and 6, exhibit excellent biological activity and pharmacological properties, making them significant for research and promising for applications in photochemistry, pesticides, and medicine. In optics, they hold important potential for applications in the preparation of luminescent and photochromic materials, as well as in optical displays and information archiving and storage. The triazine ring also possesses a unique electronic structure and chemical stability, enabling it to undergo specific reaction mechanisms to produce acids under photoexcitation, thus having wide applications in electronic information transmission. For example, patent CN109803957 describes triazine fused-ring derivatives and their applications in organic electronic devices. In pesticides, due to their unique structure, they were among the earliest and most commonly used main skeletons in insecticides. In medicine, the triazine ring in S-triazine compounds can interact with the hydrogen bonds of protein receptors through a π-π conjugated system.

[0003] Therefore, it plays a positive role in influencing the electrostatic interactions of intracellular biomacromolecules (such as proteins and nucleic acids), regulating the electronic mobility of intramolecular conjugated systems, and making compounds more likely to bind to specific targets. For example, patent CN114507221 describes a triazine compound and its use in the preparation of antiviral drugs.

[0004] The preparation of S-triazine compounds includes acid-catalyzed reactions, microwave cross-coupling reactions, metal catalysis, cyanuric chloride-related reactions, and cyclization reactions. However, these existing synthetic methods suffer from various problems, such as cumbersome steps, harsh reaction conditions, low yields, or the use of expensive catalysts.

[0005] Therefore, the current bottleneck problem that urgently needs to be solved is how to prepare high-yield and high-purity S-triazine compounds with low cost and simple process. Solving this problem is also beneficial to the green chemistry and sustainable development of the synthesis of such compounds. The content of this invention solves this bottleneck problem in a new way. Summary of the Invention

[0006] This invention proposes a method for preparing a class of bis(trichloromethyl)S-triazine compounds. Starting with benzonitrile compounds, the method involves a cyclotrimerization reaction with trichloroacetonitrile, followed by a Knauvengel reaction with benzaldehyde compounds to obtain the bis(trichloromethyl)S-triazine compounds. The process of this invention is simple, and the prepared bis(trichloromethyl)S-triazine compounds have high purity and high yield, meeting the current industrial demand for high-purity bis(trichloromethyl)S-triazine compounds.

[0007] Taking into account the factors mentioned in the background art above, this application prepared compounds and conducted inhibitory experiments on tumor cells, especially human liver cancer cells HepG2. It was found that the compounds exhibited excellent inhibitory effects on these cells, and in most cases, they surpassed the control cisplatin.

[0008] The technical solution of this invention is: The overall reaction formula for the preparation of a class of bis(trichloromethyl)S-triazine compounds is as follows:

[0009] Specifically, the preparation method of bis(trichloromethyl)S-triazine compounds provided by this invention mainly includes the following steps: S1. Add benzonitrile compound raw material, aluminum trihalide and trichloroacetonitrile to a three-necked flask, stir and pass hydrogen chloride gas at -10 to 0℃, react for 1 to 8 hours, after the reaction solution solidifies, raise the temperature and stir for 1 to 6 hours. Preferably, the aluminum trihalide is aluminum tribromide; Then, add water (3 times the volume of the reaction solution) and 100 mL of petroleum ether to the reaction solution to wash away excess acid and raw materials. After drying, recrystallize with methanol to produce a precipitate, filter, and obtain powder products 1-5. S2. Add acetonitrile, aluminum trihalide and trichloroacetonitrile to a three-necked flask, stir and pass hydrogen chloride gas at -10 to 0℃, react for 1 to 8 hours, after the reaction solution solidifies, raise the temperature and stir for 1 to 6 hours. Preferably, the aluminum trihalide is aluminum tribromide; Next, add water (3 times the volume of the reaction solution) and 100 mL of petroleum ether to the reaction solution to wash away excess acid and raw materials. After drying, recrystallize with methanol to produce a precipitate, filter, and obtain white powder intermediate I. S3. Take intermediate I obtained in S2, piperidine, substituted benzaldehyde, acetic anhydride (which serves as an auxiliary agent or catalyst) and toluene into a single-necked flask, heat to 40-100℃ under nitrogen protection and stir for 2-10 hours, remove the solvent by vacuum distillation, and obtain solid products, namely compounds 6-9, by column chromatography of the residue.

[0010] The substitution reaction in S1 is carried out at a low temperature of 0-10℃. This is because excessively high temperatures will increase impurities. Therefore, it is necessary to control the reaction temperature at 0-10℃ to avoid the increased cost caused by heating while still achieving good reaction results.

[0011] Preferably, in S1, the molar ratio of benzonitrile compound, aluminum tribromide, and trichloroacetonitrile is 1:0.1-0.5:6.0-10.0.

[0012] Preferably, in S3, the molar ratio of intermediate I: piperidine: acetic anhydride: benzaldehyde is 1:0.5-0.7:0.5-0.7:1.1-1.3; and the vacuum degree during filtration is 0.05 MPa.

[0013] Preferably, in S3, the mass ratio of intermediate I to toluene is 1:20.

[0014] This invention uses benzonitrile compounds as starting materials, which undergo a cyclotrimerization reaction with trichloroacetonitrile and aluminum tribromide to synthesize intermediate I. Then, a Knauvengel reaction is carried out catalyzed by piperidine and acetic acid to finally generate the target product, bis(trichloromethyl)S-triazine compound.

[0015] The positive and progressive effects of this invention compared to the prior art are as follows: (1) The bis(trichloromethyl)S-triazine compounds prepared by the method of the present invention have high yields, with the yield of each reaction step exceeding 70% and the total yield also exceeding 70%, which is 15 percentage points higher than the total yield of the preparation of bis(trichloromethyl)S-triazine compounds by the prior art; the purity of the final product can reach 99.7%; which meets the current demand for high purity of bis(trichloromethyl)S-triazine compounds; (2) The present invention uses substituted benzonitrile as the starting material to prepare high-purity bis(trichloromethyl)S-triazine compounds. Acetic anhydride is used as a dehydrating agent and catalyst in step S3 to ensure reaction efficiency. (3) The preparation method provided by the present invention has easy temperature control throughout the reaction process, is simple and easy to implement, has few intermediate impurities, saves preparation costs and improves product purity, and is suitable for industrial application. (4) The compounds obtained in this invention have a good inhibitory activity on the growth inhibition rate of human liver cancer cells HepG2, and almost all of them are stronger than the inhibitory effect of the control cisplatin.

[0016] (5) The compounds obtained in this invention have good solubility and obvious absorption at around 193nm. They can not only be used as a reserve of high-end photoacid products, but also as an auxiliary means of photodynamic cancer treatment. Attached Figure Description

[0017] Figure 1 The results show the effects of S-triazine compounds 1-9 on the growth inhibition rate of HepG2 human liver cancer cells. Detailed Implementation

[0018] To enable those skilled in the art to better understand the present invention, the present invention will now be further described in conjunction with specific embodiments.

[0019] The preparation methods of compounds 1-5 include the following steps: Example 1 Synthesis of 2-(4-fluorophenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine (denoted as: Compound 1) Add 5g of p-fluorobenzonitrile, 1.62g of aluminum tribromide and 35.7g of trichloroacetonitrile to a three-necked flask, stir at -10℃, and saturate the solution with anhydrous HCl gas. Then stop the HCl gas and stir at the same temperature for 5 hours. After the reaction was complete, the oil bath was heated to room temperature to melt the solid. 200 mL of pure water and 100 mL of petroleum ether were added, the acid was washed off, and the mixture was dried. The residue was recrystallized from methanol, and after drying, 32.5 g of a white solid was obtained, with a yield of 80.9% and a purity of 99.4%. 1 H NMR (500 MHz, CDCl3) δ 8.82-8.60 (m, 2H), 7.36-7.14 (m, 2H).

[0020] Comparative Example 1 The preparation of compound 1 was carried out in the same manner as in Example 1, except that aluminum tribromide was replaced with an equimolar amount of aluminum trichloride. The final product was 24.2 g of white solid, with a yield of 60.2%.

[0021] Example 2 Synthesis of 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine (Compound 2) In a three-necked flask, the raw materials were changed to 5g of p-methoxybenzonitrile, 1.0g of aluminum tribromide and 32.5g of trichloroacetonitrile. The mixture was stirred at -5℃ and anhydrous HCl gas was introduced to saturate the solution. After that, the HCl gas was stopped and the mixture was kept at the same temperature and stirred for 6 hours.

[0022] The remaining procedures were the same as in Example 1, yielding 13.5 g of a white solid, with a yield of 85.3% and a purity of 99.5%. 1 H NMR (500MHz, CDCl3) δ 8.84-8.49 (m, 2H), 7.13-6.92 (m, 2H), 3.94 (s, 3H).

[0023] Example 3 Synthesis of 2-(4-hydroxyphenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine (Compound 3) In a three-necked flask, the raw materials were changed to 3.5 g of p-hydroxybenzonitrile, 0.8 g of aluminum tribromide, and 25.5 g of trichloroacetonitrile. The mixture was stirred at 0 °C, and anhydrous HCl gas was introduced to saturate the solution. After the HCl gas was stopped, the mixture was kept at the same temperature and stirred for 4 hours.

[0024] The remaining procedures were the same as in Example 1, yielding 9.4 g of a white solid, with a yield of 79.2% and a purity of 99.3%. 1 H NMR (500MHz, CDCl3) δ 8.98-8.24 (m, 2H), 7.42-7.06 (m, 2H).

[0025] Example 4 Synthesis of 2-(2-bromophenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine (Compound 4) In a three-necked flask, the raw materials were changed to 4.0 g of o-bromobenzonitrile, 0.8 g of aluminum tribromide and 22.9 g of trichloroacetonitrile. The mixture was stirred at -4 °C and anhydrous HCl gas was introduced to saturate the solution. After the HCl gas was stopped, the mixture was kept at the same temperature and stirred for 6 hours.

[0026] The remaining procedures were the same as in Example 1, yielding 8.8 g of a white solid, with a yield of 85.1% and a purity of 99.7%. 1 H NMR (500MHz, DMSO) δ 8.11 (dd, J = 7.7, 1.8 Hz, 1H), 7.92 (dd, J = 7.9, 1.1 Hz, 1H), 7.71-7.61 (m, 2H).

[0027] Example 5 Synthesis of target compound 4, 2-(2-chlorophenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine (compound 5) In a three-necked flask, the raw materials were changed to 3.5 g of o-chlorobenzonitrile, 1.3 g of aluminum tribromide and 22.3 g of trichloroacetonitrile. The mixture was stirred at 0 °C and anhydrous HCl gas was introduced to saturate the solution. After that, the HCl gas was stopped and the mixture was kept at the same temperature and stirred for 5.5 h. The remaining procedures were the same as in Example 1, yielding 8.9 g of a white solid, with a yield of 82.1% and a purity of 99.7%. 1 H NMR (400MHz, DMSO) δ 8.19-8.13 (m, 1H), 7.75-7.71 (m, 2H), 7.65 (ddd, J = 7.8, 5.7, 3.0 Hz, 1H).

[0028] Comparative Example 2 The preparation of compound 5 was carried out in the same manner except that aluminum tribromide was replaced with an equimolar amount of aluminum trichloride, yielding 7.86 g of white solid with a yield of 72.5%.

[0029] Example 6 Synthetic intermediate I: In a three-necked flask, add 5 g of acetonitrile, 1.62 g of aluminum tribromide and 20.25 g of trichloroacetonitrile, stir at -10°C, and saturate the solution with anhydrous HCl gas. Then stop HCl gas flow and keep the mixture at this temperature for 6 hours.

[0030] The subsequent steps were the same as in Example 1, yielding 33.5 g of a white solid, with a yield of 84.1% and a purity of 99.4%. 1 H NMR (500 MHz, DMSO) δ 2.89 (s, 3H).

[0031] Example 7 Synthesis of compound 2-(3,4-dimethoxystyryl)-4,6-bis(trichloromethyl)-1,3,5-triazine (compound 6).

[0032] In a round-bottom flask, 4 g of intermediate I synthesized in Example 6, 2.4 g of 3,4-dimethoxybenzaldehyde, and 30 mL of toluene were added. While stirring, 0.68 g of acetic anhydride and 0.5 g of piperidine were added to the reactants. After the addition was complete, the reaction was carried out at 50°C for approximately 8 hours. After the reaction was complete, the solvent was removed by vacuum distillation to obtain a crude brown oily product. This crude product was then subjected to column chromatography to obtain the final product, which, after drying, yielded 4.2 g of a white solid, with a yield of 72.6% and a purity of 99.7%. 1 H NMR (500 MHz, CDCl3) δ8.44 (d, J = 15.7 Hz, 1H), 7.32 (dd, J = 8.3, 1.9 Hz, 1H), 7.23 (dd, J =25.7, 8.8 Hz, 2H), 6.94 (d, J = 8.3 Hz, 1H), 3.97 (d, J = 6.3 Hz, 6H).

[0033] Comparative Example 3 In the synthesis of compound 6, the overall operation was the same as in Example 7, except that acetic anhydride was not added to the reaction system. The rest was the same, and 1.23 g of white solid was finally obtained, with a yield of 21.3% and an increase in impurities.

[0034] Comparative Example 4 In the synthesis of compound 6, the overall operation was the same as in Example 7, except that acetic anhydride was replaced with an equimolar amount of acetic acid (0.4 g) added to the reaction system. The rest was the same, and finally 3.6 g of white solid was obtained, with a yield of 63.2%.

[0035] Example 8 The synthesis of compounds 7-9 was performed in the same manner as in Example 7, except that the heating temperatures for compounds 7-9 were 50°C, 55°C, and 70°C, respectively. The results are as follows: 2-(3-chloro-1-styryl)-4,6-bis(trichloromethyl)-1,3,5-triazine (compound 7). White solid, 4.1 g, yield 75.6%, purity 99.6%. 1 H NMR (500 MHz, CDCl3) δ 8.41 (d, J = 15.9 Hz, 1H),7.72 (t, J = 1.8 Hz, 1H), 7.60 (dd, J = 5.0, 3.7 Hz, 1H), 7.48-7.37 (m, 2H),7.34 (d, J = 15.8 Hz, 1H).

[0036] 2-(2-Bromo-1-Styryl)-4,6-bis(trichloromethyl)-1,3,5-triazine (Compound 8), white solid, 4.2 g, yield 70.2%, purity 99.4%. 1 H NMR (500 MHz, CDCl3) δ 8.88 (d, J = 15.8 Hz, 1H), 7.78 (dd, J = 7.8, 1.5 Hz, 1H), 7.63 (dd, J = 8.0, 1.0 Hz, 1H), 7.35 (t, J =7.5 Hz, 1H), 7.28-7.24 (m, 1H), 7.23 (dd, J = 9.0, 6.8 Hz, 1H).

[0037] 2-(4-nitro-1-styryl)-4,6-bis(trichloromethyl)-1,3,5-triazine (compound 9), white solid, 3.4 g, yield 70.8%, purity 99.3%. 1 H NMR (500 MHz, CDCl3) δ 8.51 (d, J = 15.9 Hz, 1H), 8.33 (dd, J = 8.8 Hz, 2H), 7.89 (d, J = 8.8 Hz, 2H), 7.48 (d, J = 15.9 Hz, 1H).

[0038] Example 9 Solubility experiments of S-triazine compounds 1-9 in organic solvents (see Table 1) Table 1 Solubility of S-triazine compounds in organic solvents

[0039] Note: √√√ Easily soluble; √√ soluble; √ Slightly soluble; × insoluble The synthesized S-triazine compounds are more soluble in highly polar solvents such as ethanol, methanol, and acetonitrile. Their solubility in moderately polar dichloromethane varies depending on the attached groups. They exhibit poor solubility in the nonpolar solvent methyl tert-butyl ether. This indicates that highly polar solvents can attract the polar part of the triazine compound molecule through dipole-dipole interactions or hydrogen bonds, thereby enhancing the solubility of the triazine compounds in solvents.

[0040] Example 10 UV absorption experiments of S-triazine compounds 1-9 (see Table 2) Table 2. UV absorption data of the synthesized S-triazine compounds

[0041] The different substituents of the triazine ring affect the position of the ultraviolet absorption band of the compounds. In compounds 1-5, the main structure of the triazine ring and the substituent benzene ring are connected by single bonds, and they have strong absorption at 193 nm. In compounds 6-9, the main structure of the triazine ring and the substituent benzene ring are connected by double bonds. The carbon-carbon double bond of the alkene and the conjugated system of the triazine form a larger conjugated system, and they have relatively obvious absorption at 360 nm.

[0042] Example 11 Growth inhibition experiments of S-triazine compounds 1-9 on HepG2 human liver cancer cells (see...) Figure 1 This application used the MTT assay to evaluate the growth inhibitory effect of compound ST1-ST25 on human hepatocellular carcinoma cells HepG2. The specific procedure was as follows: First, cells in good growth condition were washed with PBS, digested with trypsin, and digested with fresh complete culture medium to terminate the digestion. The diluted cell suspension was then placed in an incubator using a pipette. After 24 h, the culture medium in the wells was aspirated, and 100 µL of each drug at the prepared final concentration was added to each well. Blank wells and control wells were set up. The blank group was only added with an equal amount of culture medium, and 0.1% DMSO was used as a solvent control. For each drug concentration, four replicates were performed to ensure accurate drug addition. 48 hours after drug addition, 10 μL of LMTT test solution was added to each well, protected from light, and then placed in an incubator for 4 hours. The supernatant was removed, and 150 μL of DMSO solution was added to each well. The well was shaken and the absorbance at 570 nm was measured using a microplate reader. The OD value was measured, and the inhibition rate % was calculated as 1 - (OD value of the drug group - OD value of the blank well) / (OD value of the control group - OD value of the blank well) × 100%. The IC50 values ​​of compounds (1~9) were calculated using GraphPad software.

[0043] from Figure 1 In the experiment on the growth inhibition of S-triazine compounds 1-9 on HepG2 human liver cancer cells, it was found that, except for compound 1, almost all compounds had a positive inhibitory effect compared with the control. In particular, compound 6 had an excellent inhibitory effect on the growth of HepG2 human liver cancer cells, which was unexpected before. The excellent ultraviolet absorbance and solubility of this compound contribute to the tumor inhibitory effect of the structure and provide a structural idea for the combination of photodynamic therapy and chemical methods for tumor treatment.

[0044] In summary, the preparation method of a class of bis(trichloromethyl)S-triazine compounds provided by this invention optimizes the reaction steps, making the entire preparation process easier to control in terms of temperature, simplifying the method, reducing impurities, lowering costs, and improving purity. It is not only suitable for use as a photoacid in the chemical industry, but also beneficial for the screening of tumor treatment drugs.

Claims

1. A class of bis(trichloromethyl)S-triazine compounds, characterized in that, The general formula of the compound is: ,or , R is selected from one of the following: an oxygen-containing group, halogen, hydroxyl group, and hydrogen, wherein the oxygen-containing group does not include hydroxyl groups.

2. The bis(trichloromethyl)S-triazine compound as described in claim 1, characterized in that, The oxygen-containing group is selected from one of methoxy, dimethoxy, and nitroso.

3. A class of bis(trichloromethyl)S-triazine compounds as described in any one of claims 1-2, characterized in that, The molecular structural formula of the compound is any one of the following 1 to 9: 。 4. The method for preparing a class of bis(trichloromethyl)S-triazine compounds as described in claim 3, characterized in that, The synthetic steps for structures 1-5 in the molecular formula of the compound are as follows: S1-1: Add benzonitrile compounds, aluminum trihalide and trichloroacetonitrile to a three-necked flask, and continuously pass hydrogen chloride gas while stirring at -10 to 0°C for 1 to 8 hours. After the reaction solution solidifies, raise the temperature to room temperature and stir for 1 to 6 hours. S1-2: Add 3 times the volume of water and 100 mL of petroleum ether to the reaction solution obtained in S1-1, wash off excess acid and benzonitrile compounds, dry, recrystallize with methanol to produce a precipitate, filter, and obtain the product with structural formulas 1 to 5 as described in claim 3. The synthetic steps for structures 6-9 in the molecular structure of the compound are as follows: S2-1: Add acetonitrile, aluminum trihalide and trichloroacetonitrile to a three-necked flask, stir at -10 to 0°C and continuously pass hydrogen chloride gas through, react for 1 to 8 hours, and after the reaction solution solidifies, raise the temperature to room temperature and stir for 1 to 6 hours. S2-2: Add 3 times the volume of water and 100 mL of petroleum ether to the reaction solution in S2-1, wash off excess acid and acetonitrile raw materials, dry, recrystallize with methanol to produce a precipitate, filter, and obtain white powder intermediate I. S2-3: Piperidine, substituted benzaldehyde compounds, acetic anhydride or acetic acid, toluene, and intermediate I obtained in S2-2 are added to a single-necked flask. The mixture is heated to 40-100°C under nitrogen protection and stirred for 2-10 hours. The solvent is removed by vacuum distillation, and the residue is subjected to column chromatography to obtain the product with molecular structural formula 6-9 as described in claim 3.

5. The method for preparing a class of bis(trichloromethyl)S-triazine compounds as described in claim 4, characterized in that, In S1-1, the molar ratios of benzonitrile compounds, aluminum trihalide, and trichloroacetonitrile are 1:0.1 to 0.5:6.0 to 10.0, respectively.

6. The method for preparing a class of bis(trichloromethyl)S-triazine compounds as described in claim 4, characterized in that, In S2-1, the mass ratios of acetonitrile, aluminum trihalide, and trichloroacetonitrile are 4~6:1.5~2:20~21, respectively.

7. The method for preparing a class of bis(trichloromethyl)S-triazine compounds as described in claim 6, characterized in that, In S2-1, the mass ratios of acetonitrile, aluminum trihalide, and trichloroacetonitrile are 5:1.62:20.25, respectively.

8. The method for preparing a class of bis(trichloromethyl)S-triazine compounds as described in claim 4, characterized in that, In S2-3, the molar ratio between intermediate I, piperidine, acetic anhydride or acetic acid, and benzaldehyde compounds is 1:0.5-0.7:0.5-0.7:1.1-1.3; the mass ratio of intermediate I to toluene is 1:20; and the vacuum degree during filtration is 0.05 MPa.

9. The use of a class of bis(trichloromethyl)S-triazine compounds as described in claim 1 in the preparation of a drug for inhibiting HepG2 liver cancer cells.

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