Photochromic compound, preparation method therefor and use thereof
By synthesizing photochromic compounds and utilizing the electron-withdrawing structure of benzo[a]heterocyclic compounds, the problem of insufficient infrared absorption by glass was solved, achieving color-changing effects under illumination and charge transfer in the near-infrared region, thus improving visual comfort.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Filing Date
- 2025-06-19
- Publication Date
- 2026-07-16
AI Technical Summary
Existing glass materials have limited absorption capacity for infrared radiation, especially near-infrared radiation, and cannot effectively adjust transparency to improve comfort.
A photochromic compound was developed by synthesizing the compound through Miyaura borylation reaction, Suzuki coupling reaction, Grignard reagent reaction, cyclization reaction, cross-coupling reaction and demethylation reaction, introducing an electron-withdrawing structure of benzo[a] heterocyclic ring to achieve the color-changing effect.
It achieves a color-changing effect under illumination and becomes colorless and transparent in the dark, effectively reducing heat exchange and realizing a charge transfer effect in the near-infrared region, thus improving visual comfort.
Smart Images
Figure CN2025101941_16072026_PF_FP_ABST
Abstract
Description
A photochromic compound, its preparation method and application Technical Field
[0001] This invention relates to the field of photochromic materials technology, and in particular to a photochromic compound, its preparation method, and its application. Background Technology
[0002] With the increasing standards for building energy efficiency and the growing demand for comfort in living and working environments, infrared absorption functionality is gradually expanding into various fields such as architectural glass, automotive glass, and protective glass for electronic devices. Glass itself is a transparent material, and traditional glass has limited absorption capacity for infrared radiation, especially near-infrared radiation. During the glass manufacturing process, specific absorbing materials are typically added to enhance the glass's infrared absorption capacity. These absorbing materials are uniformly dispersed within the glass matrix, allowing the glass to effectively absorb infrared radiation within a specific wavelength range, thereby achieving heat insulation or reducing infrared penetration. Commonly used absorbing materials include metal oxides (such as iron oxides and cobalt oxides) and rare earth element compounds.
[0003] Photochromic materials can automatically adjust the transparency of glass according to changes in ambient light. Under strong light or strong ultraviolet radiation, the photochromic material undergoes a structural change, darkening the glass and reducing the transmittance of visible light and infrared rays. When the light weakens, the photochromic material returns to its initial structure, making the glass transparent again. This adaptive adjustment function based on light intensity effectively reduces glare in indoor lighting and improves visual comfort.
[0004] Therefore, developing photochromic materials with a wide absorption range and applying them to glass or interlayers to improve people's comfort has broad application prospects. Summary of the Invention
[0005] The purpose of this invention is to provide a photochromic compound, its preparation method, and its application, addressing the shortcomings of existing technologies.
[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:
[0007] This invention provides a photochromic compound, the structural formula of which is:
[0008] Among them, R1, R2, R7, and R8 are independently hydrogen, halogen, hydroxyl, alkyl, alkoxy, amino, aryl, or heteroaryl.
[0009] R3 and R4 are independently hydrogen, halogen, hydroxyl, alkyl, heterocyclic alkyl, alkoxy, aryl, or heteroaryl;
[0010] R is hydrogen, alkyl, cycloalkyl, or aryl;
[0011] X is N-R9, O, or S;
[0012] R9 is hydrogen, alkyl, aryl, or heteroaryl.
[0013] Preferably, the photochromic compound is any one of the following structural formulas:
[0014] The present invention also provides a method for preparing the aforementioned photochromic compound, comprising the following steps:
[0015] (1) Compound A, [1,1'-bis(diphenylphosphino)ferrocene]palladium dichloride, pinacol diborate, potassium acetate, toluene and water were subjected to the Miyaura borylation reaction to obtain the intermediate product;
[0016] (2) The intermediate product, compound B, tetra(triphenylphosphine)palladium, potassium carbonate solution and tetrahydrofuran were subjected to a Suzuki coupling reaction to obtain compound C;
[0017] (3) Compound C, Grignard reagent and tetrahydrofuran are mixed and reacted to obtain compound D;
[0018] (4) Compound D, p-toluenesulfonic acid pyridinium salt and chloroform were subjected to a cyclization reaction to obtain compound E;
[0019] (5) Compound E, compound F, tris(dibenzylacetone)palladium, cesium carbonate, toluene and water were cross-coupled to obtain compound G;
[0020] (6) Compound G, boron tribromide and chloroform were subjected to a demethylation reaction to give compound H;
[0021] (7) Mix compound H, compound J, p-toluenesulfonic acid pyridine salt and dichloromethane and react to obtain the photochromic compound.
[0022] Preferably, the structural formula of compound A in step (1) is as follows: Among them, R3 and R4 are independently hydrogen, halogen, hydroxyl, alkyl, heterocyclic alkyl, alkoxy, aryl or heteroaryl;
[0023] In step (1), the molar ratio of compound A, [1,1'-bis(diphenylphosphino)ferrocene]palladium dichloride and pinacol diborate is 48-52:1:58-63, and the molar mass ratio of compound A, potassium acetate, toluene and water is 48-52 mmol:1-2 g:120-180 g:10-15 g; the temperature of the Miyaura borylation reaction is 70-90 °C, and the time of the Miyaura borylation reaction is 20-28 h.
[0024] Preferably, the structural formula of compound B in step (2) is as follows: Wherein, X is N-R9, O or S, and R9 is hydrogen, alkyl, aryl or heteroaryl;
[0025] The molar ratio of compound B in step (2), tetra(triphenylphosphine)palladium, and compound A in step (1) is 75-80:2:48-52; the mass molar ratio of potassium carbonate solution, tetrahydrofuran, and compound A in step (1) is 48-52 g:200-300 g:48-52 mmol; the concentration of potassium carbonate solution is 1.5-2.5 mol / L; the temperature of the Suzuki coupling reaction is 50-70 °C; and the time of the Suzuki coupling reaction is 12-24 h.
[0026] Preferably, the Grignard reagent in step (3) has the structural formula R-Mg-Br, where R is hydrogen, alkyl, cycloalkyl or aryl;
[0027] In step (3), the molar volume ratio of compound C, Grignard reagent, and tetrahydrofuran is 32–38 mmol: 72–78 mmol: 250 mL; the reaction temperature is 20–30 °C, and the reaction time is 14–24 h.
[0028] The molar ratio of p-toluenesulfonic acid pyridine salt in step (4) to compound C in step (3) is 12-16:32-38, and the molar volume ratio of p-toluenesulfonic acid pyridine salt to chloroform is 12-16 mmol:100 mL; the cyclization reaction temperature is 20-30 °C, and the cyclization reaction time is 1-3 h.
[0029] Preferably, the structural formula of compound F in step (5) is as follows: Among them, R7 and R8 are independently hydrogen, halogen, hydroxyl, alkyl, alkoxy, amino, aryl or heteroaryl;
[0030] In step (5), the molar ratio of compound E, compound F, tris(dibenzylacetone)palladium, cesium carbonate, toluene, and water is 15–20 mmol: 25–30 mmol: 0.5–1.5 mmol: 34–38 mmol: 250 g: 20–30 g; the temperature of the cross-coupling reaction is 90–110 °C, and the time of the cross-coupling reaction is 16–24 h.
[0031] Preferably, the molar volume ratio of compound G, boron tribromide and chloroform in step (6) is 10-15 mmol: 15-20 mmol: 10-25 mL; the temperature of the demethylation reaction is 20-30 °C and the time of the demethylation reaction is 16-24 h.
[0032] Preferably, the structural formula of compound J in step (7) is as follows: Among them, R1 and R2 are independently hydrogen, halogen, hydroxyl, alkyl, alkoxy, amino, aryl or heteroaryl;
[0033] In step (7), the molar volume ratio of compound H, compound J, p-toluenesulfonic acid pyridinium salt and dichloromethane is 2-5 mmol: 3-6 mmol: 1-4 mmol: 100 mL; the reaction temperature is 35-45 °C and the reaction time is 4-10 h.
[0034] The present invention also provides the application of the aforementioned photochromic compound in photochromic articles.
[0035] The beneficial effects of this invention include the following:
[0036] 1) The photochromic compound of the present invention can achieve a color-changing effect under light conditions, and can be colorless and transparent when returned to indoors or in the dark.
[0037] 2) By introducing an electron-withdrawing structure of a benzo[a]heterocyclic ring into the parent structure and extending the conjugated structure, the present invention can enable a charge transfer effect to occur inside the photochromic compound even in the near-infrared region, thereby achieving a color-changing effect, while effectively reducing heat exchange. Detailed Implementation
[0038] This invention provides a photochromic compound, the structural formula of which is:
[0039] Among them, R1, R2, R7, and R8 are independently hydrogen, halogen, hydroxyl, alkyl, alkoxy, amino, aryl, or heteroaryl.
[0040] R3 and R4 are independently hydrogen, halogen, hydroxyl, alkyl, heterocyclic alkyl, alkoxy, aryl, or heteroaryl;
[0041] R is hydrogen, alkyl, cycloalkyl, or aryl;
[0042] X is N-R9, O, or S;
[0043] R9 is hydrogen, alkyl, aryl, or heteroaryl.
[0044] In this invention, the photochromic compound is preferably any one of the following structural formulas:
[0045] The present invention also provides a method for preparing the aforementioned photochromic compound, comprising the following steps:
[0046] (1) Compound A, [1,1'-bis(diphenylphosphino)ferrocene]palladium dichloride, pinacol diborate, potassium acetate, toluene and water were subjected to the Miyaura borylation reaction to obtain the intermediate product;
[0047] (2) The intermediate product, compound B, tetra(triphenylphosphine)palladium, potassium carbonate solution and tetrahydrofuran were subjected to a Suzuki coupling reaction to obtain compound C;
[0048] (3) Compound C, Grignard reagent and tetrahydrofuran are mixed and reacted to obtain compound D;
[0049] (4) Compound D, p-toluenesulfonic acid pyridinium salt and chloroform were subjected to a cyclization reaction to obtain compound E;
[0050] (5) Compound E, compound F, tris(dibenzylacetone)palladium, cesium carbonate, toluene and water were cross-coupled to obtain compound G;
[0051] (6) Compound G, boron tribromide and chloroform were subjected to a demethylation reaction to give compound H;
[0052] (7) Mix compound H, compound J, p-toluenesulfonic acid pyridine salt and dichloromethane and react to obtain the photochromic compound.
[0053] In this invention, the preferred synthetic route for the photochromic compound is as follows:
[0054] In this invention, the structural formula of compound A in step (1) is as follows: Among them, R3 and R4 are preferably hydrogen, halogen, hydroxyl, alkyl, heterocyclic alkyl, alkoxy, aryl or heteroaryl;
[0055] The molar ratio of compound A, [1,1'-bis(diphenylphosphino)ferrocene]palladium dichloride, and pinacol diboron ester in step (1) is preferably 48-52:1:58-63, more preferably 49-51:1:59-62, and even more preferably 50.8:1:61; the molar ratio of compound A, potassium acetate, toluene, and water is preferably 48-52 mmol:1-2 g:120-180 g:10-15 g, and more preferably 49 mmol:1-2 g:120-180 g:10-15 g. ~51mmol:1.25~1.75g:135~165g:11~14g, more preferably 50.8mmol:1.5g:150g:12~13.5g; the temperature of the Miyaura borylation reaction is preferably 70~90℃, more preferably 75~85℃, more preferably 80℃; the time of the Miyaura borylation reaction is preferably 20~28h, more preferably 22~26h, more preferably 24h.
[0056] In this invention, the Miyaura borylation reaction in step (1) is preferably carried out in nitrogen gas, and stirring is preferably performed during the Miyaura borylation reaction; the stirring speed is preferably 150-250 rpm, and more preferably 200 rpm.
[0057] In this invention, after the Miyaura borylation reaction in step (1) is completed, it is preferable to cool to room temperature first and then perform rotary evaporation concentration; the vacuum degree of the rotary evaporation concentration is preferably -0.05 to -0.01 MPa, more preferably -0.03 to -0.02 MPa; the temperature of the rotary evaporation concentration is preferably 45 to 55°C, more preferably 50°C; the time of the rotary evaporation concentration is preferably 20 to 40 min, more preferably 30 min.
[0058] In this invention, the structural formula of the intermediate product in step (1) is: Among them, R3 and R4 are preferably hydrogen, halogen, hydroxyl, alkyl, heterocyclic alkyl, alkoxy, aryl or heteroaryl.
[0059] In this invention, the structural formula of compound B in step (2) is as follows: Wherein, X is preferably N-R9, O or S, and R9 is hydrogen, alkyl, aryl or heteroaryl;
[0060] The molar ratio of compound B, tetra(triphenylphosphine)palladium, and compound A in step (1) is preferably 75-80:2:48-52, more preferably 76.2-79:2:49-51, and even more preferably 77-78:2:50.8; the molar ratio of potassium carbonate solution, tetrahydrofuran, and compound A in step (1) is preferably 48-52g:200-300g:48-52mmol, more preferably 49-51g:220-280g:49-52mmol. The concentration of the potassium carbonate solution is preferably 1.5–2.5 mol / L, more preferably 1.75–2.25 mol / L, and more preferably 2 mol / L; the temperature of the Suzuki coupling reaction is preferably 50–70 °C, more preferably 55–65 °C, and more preferably 60 °C; the time of the Suzuki coupling reaction is preferably 12–24 h, more preferably 16–20 h, and more preferably 18 h.
[0061] In this invention, the Suzuki coupling reaction in step (2) is preferably carried out in nitrogen gas, and stirring is preferably performed during the Suzuki coupling reaction; the stirring speed is preferably 150-250 rpm, and more preferably 200 rpm.
[0062] In this invention, after the Suzuki coupling reaction in step (2) is completed, a mixed solution is obtained. Preferably, the mixed solution is first poured into hydrochloric acid, and then diluted, washed, dried, concentrated by rotary evaporation, and subjected to silica gel column chromatography in sequence. The volume molar ratio of the hydrochloric acid to compound A in step (1) is preferably 180-220 mL: 48-52 mmol, more preferably 190-210 mL: 49-51 mmol, and more preferably 200 mL: 50.8 mmol. The concentration of the hydrochloric acid is preferably 1.5-2.5 mol / L, and more preferably 2 mol / L. The dilution is preferably performed using diethyl ether, and the volume molar ratio of diethyl ether to compound A is preferably 480-520 mL: 48-52 mmol, more preferably 490-520 mL: 48-52 mmol. The washing solution is preferably 510 mL: 49–51 mmol, more preferably 500 mL: 50.8 mmol; the washing is preferably performed on the diluted organic layer, and the washing reagents are preferably water and sodium chloride solution in sequence, wherein the mass concentration of the sodium chloride solution is preferably 10–27%, more preferably 26.5%; the drying is preferably performed using anhydrous sodium sulfate; the vacuum degree of the rotary evaporation concentration is preferably -0.05 to -0.01 MPa, more preferably -0.03 to -0.02 MPa, and the rotary evaporation concentration temperature is preferably 30–60 °C, more preferably 40 °C; the reagents used for silica gel column chromatography are preferably n-hexane and dichloromethane, and the volume ratio of n-hexane to dichloromethane is preferably 6–9:3, more preferably 7–8:3.
[0063] In this invention, the structural formula of compound C in step (2) is: Wherein, R3 and R4 are preferably hydrogen, halogen, hydroxyl, alkyl, heterocyclic alkyl, alkoxy, aryl or heteroaryl; X is preferably N-R9, O or S, and R9 is preferably hydrogen, alkyl, aryl or heteroaryl.
[0064] In this invention, the Grignard reagent described in step (3) has the structural formula R-Mg-Br, wherein R is preferably hydrogen, alkyl, cycloalkyl or aryl;
[0065] The preferred molar volume ratio of compound C, Grignard reagent, and tetrahydrofuran in step (3) is 32–38 mmol: 72–78 mmol: 250 mL, more preferably 33–37 mmol: 73–77 mmol: 250 mL, and even more preferably 34.9–36 mmol: 75 mmol: 250 mL; the preferred reaction temperature is 20–30 °C, more preferably 22–28 °C, and even more preferably 25 °C; the preferred reaction time is 14–24 h, more preferably 16–20 h, and even more preferably 19 h.
[0066] The molar ratio of p-toluenesulfonic acid pyridine salt in step (4) to compound C in step (3) is preferably 12-16:32-38, more preferably 13-15:33-37, and even more preferably 14:34.9-36; the molar volume ratio of p-toluenesulfonic acid pyridine salt to chloroform is preferably 12-16 mmol:100 mL, more preferably 13-15 mmol:100 mL, and even more preferably 14 mmol:100 mL; the temperature of the cyclization reaction is preferably 20-30°C, more preferably 22-28°C, and even more preferably 25°C; the time of the cyclization reaction is preferably 1-3 h, more preferably 1.5-2.5 h, and even more preferably 2 h.
[0067] In this invention, the reaction described in step (3) is preferably carried out in nitrogen gas, and stirring is preferably performed during the reaction; the stirring speed is preferably 150 to 250 rpm, and more preferably 200 rpm.
[0068] In this invention, step (3) preferably involves mixing compound C and tetrahydrofuran first, and then adding a solution of Grignard reagent dropwise; the dropwise addition time is preferably 20 to 40 minutes, more preferably 30 minutes; the solvent used for the Grignard reagent solution is preferably diethyl ether, and the concentration of Grignard reagent in the solution is preferably 0.8 to 1.2 mol / L, more preferably 1 mol / L.
[0069] In this invention, after the reaction in step (3) is completed, a mixed solution is obtained. Preferably, the mixed solution is first poured into hydrochloric acid, and then diluted, washed, dried, concentrated by rotary evaporation, and subjected to silica gel column chromatography in sequence. The volume molar ratio of hydrochloric acid to compound C is preferably 180-220 mL: 32-38 mmol, more preferably 190-210 mL: 33-37 mmol, and even more preferably 200 mL: 34.9-36 mmol. The concentration of hydrochloric acid is preferably 1.5-2.5 mol / L, and even more preferably 2 mol / L. The dilution is preferably performed using diethyl ether, and the volume molar ratio of diethyl ether to compound C is preferably 480-520 mL: 32-38 mmol, more preferably 490-510 mL: 33-37 mmol, and even more preferably 50 mol / L. 0 mL: 34.9–36 mmol; the washing is preferably performed on the diluted organic layer, and the washing reagents are preferably water and sodium chloride solution in sequence, with the mass concentration of the sodium chloride solution preferably being 10–27%, more preferably 26.5%; the drying is preferably performed using anhydrous sodium sulfate; the vacuum degree of the rotary evaporation concentration is preferably -0.05–-0.01 MPa, more preferably -0.03–-0.02 MPa, the rotary evaporation concentration temperature is preferably 30–60 °C, more preferably 40 °C, and the rotary evaporation concentration time is preferably 20–40 min, more preferably 30 min; the reagents used in the silica gel column chromatography are preferably n-hexane and dichloromethane, with the volume ratio of n-hexane to dichloromethane preferably being 5–7:4, more preferably 6:4.
[0070] In this invention, the structural formula of compound D in step (3) is: Wherein, R3 and R4 are preferably hydrogen, halogen, hydroxyl, alkyl, heterocyclic alkyl, alkoxy, aryl or heteroaryl; R is preferably hydrogen, alkyl, cycloalkyl or aryl; X is preferably N-R9, O or S, and R9 is preferably hydrogen, alkyl, aryl or heteroaryl.
[0071] In this invention, stirring is preferably performed during the cyclization reaction in step (4); the stirring speed is preferably 150-250 rpm, and more preferably 200 rpm.
[0072] In this invention, after the cyclization reaction in step (4) is completed, a mixed solution is obtained. Preferably, the mixed solution is poured into water and stirred to obtain an organic layer. The organic layer is then sequentially washed, dried, concentrated by rotary evaporation, and subjected to silica gel column chromatography. The volume molar ratio of water to compound C in step (3) is preferably 200–1000 mL: 32–38 mmol, more preferably 400–600 mL: 33–37 mmol, and even more preferably 500 mL: 34.9–36 mmol. The stirring speed is preferably 100–400 rpm, more preferably 200 rpm, and the stirring time is preferably 5–15 min, more preferably 10 min. The washing reagent is preferably a sodium chloride solution, with a mass concentration of 10-27%, more preferably 26.5%. The drying is preferably done using anhydrous sodium sulfate. The vacuum degree for the rotary evaporation concentration is preferably -0.05 to -0.01 MPa, more preferably -0.03 MPa; the temperature for the rotary evaporation concentration is preferably 35-45°C, more preferably 40°C; and the time for the rotary evaporation concentration is preferably 20-40 min, more preferably 30 min. The reagents used for the silica gel column chromatography are preferably n-hexane and dichloromethane, with a volume ratio of n-hexane to dichloromethane preferably 92-98:5, more preferably 95:5.
[0073] In this invention, the structural formula of compound E in step (4) is: Wherein, R3 and R4 are preferably hydrogen, halogen, hydroxyl, alkyl, heterocyclic alkyl, alkoxy, aryl or heteroaryl; R is preferably hydrogen, alkyl, cycloalkyl or aryl; X is preferably N-R9, O or S, and R9 is preferably hydrogen, alkyl, aryl or heteroaryl.
[0074] In this invention, the structural formula of compound F in step (5) is as follows: Among them, R7 and R8 are preferably hydrogen, halogen, hydroxyl, alkyl, alkoxy, amino, aryl or heteroaryl.
[0075] The preferred molar ratio of compound E, compound F, tris(dibenzylacetone)palladium, cesium carbonate, toluene, and water in step (5) is 15–20 mmol: 25–30 mmol: 0.5–1.5 mmol: 34–38 mmol: 250 g: 20–30 g, more preferably 16–18.2 mmol: 27.2–29 mmol: 0.7–1.2 mmol: 35–37 mmol: 250 g: 22–28 g, and even more preferably 17 mmol: 28 mmol: 0.9 mmol: 36.5 mmol: 250 g: 25 g; the preferred temperature for the cross-coupling reaction is 90–110 °C, more preferably 95–105 °C, and even more preferably 100 °C; the preferred time for the cross-coupling reaction is 16–24 h, more preferably 18–22 h, and even more preferably 20 h.
[0076] In this invention, the cross-coupling reaction in step (5) is preferably carried out in nitrogen gas, and stirring is preferably performed during the cross-coupling reaction; the stirring speed is preferably 200-300 rpm, and more preferably 250 rpm.
[0077] In this invention, after the cross-coupling reaction in step (5) is completed, a mixed solution is obtained. Preferably, the mixed solution is poured into water and then sequentially diluted, washed, dried, concentrated by rotary evaporation, and subjected to silica gel column chromatography. The volume molar ratio of water to compound E is preferably 200–1000 mL: 15–20 mmol, more preferably 400–600 mL: 16–18.2 mmol, and even more preferably 500 mL: 17 mmol. The dilution is preferably performed using dichloromethane, and the volume molar ratio of dichloromethane to compound E is preferably 30–200 mL: 15–20 mmol, more preferably 50–100 mL: 16–18.2 mmol, and even more preferably 80 mL: 17 mmol. The washing is preferably performed using dichloromethane. The diluted organic layer is washed, preferably with water and sodium chloride solution in that order, with the sodium chloride solution having a mass concentration of 10-27%, more preferably 26.5%. Drying is preferably done with anhydrous sodium sulfate. The vacuum degree for rotary evaporation concentration is preferably -0.05 to -0.01 MPa, more preferably -0.03 to -0.02 MPa; the temperature for rotary evaporation concentration is preferably 30-60°C, more preferably 40°C; and the time for rotary evaporation concentration is preferably 20-40 min, more preferably 30 min. The reagents used for silica gel column chromatography are preferably n-hexane and dichloromethane, with a volume ratio of n-hexane to dichloromethane preferably 92-98:5, more preferably 95:5.
[0078] In this invention, the structural formula of compound G in step (5) is:
[0079] Wherein, R3 and R4 are preferably hydrogen, halogen, hydroxyl, alkyl, heterocycloalkyl, alkoxy, aryl or heteroaryl; R7 and R8 are preferably hydrogen, halogen, hydroxyl, alkyl, alkoxy, amino, aryl or heteroaryl; R is preferably hydrogen, alkyl, cycloalkyl or aryl; X is preferably N-R9, O or S, and R9 is preferably hydrogen, alkyl, aryl or heteroaryl.
[0080] In this invention, the molar volume ratio of compound G, boron tribromide, and chloroform in step (6) is preferably 10-15 mmol: 15-20 mmol: 10-25 mL, more preferably 11-14 mmol: 16-19 mmol: 13-20 mL, and even more preferably 12-13 mmol: 18 mmol: 18 mL; the temperature of the demethylation reaction is preferably 20-30°C, more preferably 22-28°C, and even more preferably 25°C; the time of the demethylation reaction is preferably 16-24 h, more preferably 18-22 h, and even more preferably 20 h.
[0081] In this invention, stirring is preferably performed during the demethylation reaction in step (6); the stirring speed is preferably 150-250 rpm, and more preferably 200 rpm.
[0082] In this invention, after the demethylation reaction in step (6) is completed, a mixed solution is obtained. Preferably, the mixed solution is poured into a saturated sodium bicarbonate solution and then subjected to dilution, extraction, washing, drying, rotary evaporation concentration, and silica gel column chromatography in sequence. The volume molar ratio of the saturated sodium bicarbonate solution to compound G is preferably 20-100 mL: 10-15 mmol, more preferably 40-60 mL: 11-14 mmol, and even more preferably 50 mL: 12 mmol. The dilution is preferably performed using dichloromethane, and the volume molar ratio of dichloromethane to compound G is preferably 20-100 mL: 10-15 mmol, more preferably 40-60 mL: 11-14 mmol, and even more preferably 50 mL: 12 mmol. During the dilution process, stirring is preferably performed, with a stirring speed preferably 100-400 rpm, more preferably 200 rpm, and a stirring time preferably 5-15 min, more preferably 10 min. The extraction is preferably performed by extracting the aqueous layer obtained after dilution, and the extraction solvent is preferably dichloromethane. The extraction is performed using chloromethane, preferably 2 to 4 times, more preferably 3 times. The volume molar ratio of the extractant to compound G in each extraction is preferably 20 to 100 mL: 10 to 15 mmol, more preferably 40 to 60 mL: 11 to 14 mmol, and even more preferably 50 mL: 12 mmol. The washing is preferably performed on the organic layer obtained after extraction, using water and sodium chloride solution as the washing reagents in sequence. The mass concentration of the sodium chloride solution is preferably 10 to 27%, more preferably 26.5%. The drying is preferably performed using anhydrous sodium sulfate. The vacuum degree of the rotary evaporation concentration is preferably -0.05 to -0.01 MPa, more preferably -0.03 MPa. The temperature of the rotary evaporation concentration is preferably 20 to 30°C, more preferably 25°C. The time of the rotary evaporation concentration is preferably 20 to 40 min, more preferably 30 min. The reagents used in the silica gel column chromatography are preferably n-hexane and dichloromethane, with a volume ratio of n-hexane to dichloromethane preferably 4 to 6:5, more preferably 5:5.
[0083] In this invention, the structural formula of compound H in step (6) is: Wherein, R3 and R4 are preferably hydrogen, halogen, hydroxyl, alkyl, heterocycloalkyl, alkoxy, aryl or heteroaryl; R7 and R8 are preferably hydrogen, halogen, hydroxyl, alkyl, alkoxy, amino, aryl or heteroaryl; R is preferably hydrogen, alkyl, cycloalkyl or aryl; X is preferably N-R9, O or S, and R9 is preferably hydrogen, alkyl, aryl or heteroaryl.
[0084] In this invention, the structural formula of compound J in step (7) is as follows: Wherein, R1 and R2 are preferably hydrogen, halogen, hydroxyl, alkyl, alkoxy, amino, aryl or heteroaryl;
[0085] The preferred molar volume ratio of compound H, compound J, pyridinium p-toluenesulfonate, and dichloromethane in step (7) is 2–5 mmol: 3–6 mmol: 1–4 mmol: 100 mL, more preferably 3–4 mmol: 4–5 mmol: 2–3 mmol: 100 mL, and even more preferably 3.8 mmol: 4.7 mmol: 2.8 mmol: 100 mL; the preferred reaction temperature is 35–45 °C, more preferably 38–42 °C, and even more preferably 40 °C; the preferred reaction time is 4–10 h, more preferably 6–8 h, and even more preferably 7 h.
[0086] In this invention, the reaction described in step (7) is preferably carried out in nitrogen gas, and stirring is preferably performed during the reaction; the stirring speed is preferably 100-200 rpm, and more preferably 150 rpm.
[0087] In this invention, after the reaction in step (7) is completed, a mixed solution is obtained. Preferably, the mixed solution is poured into ice water, and then extracted to obtain an organic phase. The organic phase is then subjected to rotary evaporation for concentration and silica gel column chromatography in sequence. The volume molar ratio of the ice water to compound H is preferably 50-250 mL: 2-5 mmol, more preferably 100-200 mL: 3-4 mmol, and even more preferably 150 mL: 3.8 mmol. The extractant used in the extraction is preferably toluene, and the number of extractions is preferably 2-4 times, more preferably 3 times. The volume molar ratio of the extractant to compound H used in a single extraction is preferably 150-250 mL: The concentration is 2-5 mmol, more preferably 170-220 mL: 3-4 mmol, and more preferably 200 mL: 3.8 mmol; the vacuum degree of the rotary evaporation concentration is preferably -0.05 to -0.01 MPa, more preferably -0.03 to -0.02 MPa, the temperature of the rotary evaporation concentration is preferably 30-60℃, more preferably 40℃, and the time of the rotary evaporation concentration is preferably 20-40 min, more preferably 30 min; the reagents used in the silica gel column chromatography are preferably petroleum ether and dichloromethane, and the volume ratio of petroleum ether to dichloromethane is preferably 0.5-2:1, more preferably 1:1.
[0088] The present invention also provides the application of the aforementioned photochromic compound in photochromic articles.
[0089] In this invention, the application of the photochromic compound in photochromic products preferably involves preparing the photochromic compound into a photochromic composition, and then preparing it into a photochromic product.
[0090] In this invention, the photochromic composition preferably comprises the photochromic compound and an organic polymer, wherein the organic polymer preferably comprises one or more of polystyrene, poly(meth)acrylate, polycarbonate, polyurethane, epoxy resin, polyethylene glycol, polyurethane, polysiloxane, polyether, polyamide, polyester, polyacrylonitrile, copolymers containing vinyl or / and vinyl alcohol, cellulose acetate, cellulose acetate butyrate, and polyvinyl butyral, as well as homopolymers and / or copolymers derived from the above compounds.
[0091] In this invention, the photochromic composition preferably further comprises one or more of the following: surfactant, photoinitiator, thermal initiator, polymerization inhibitor, solvent, light stabilizer, heat stabilizer, release agent, defoamer, rheology control agent, leveling agent, free radical scavenger, and adhesion promoter.
[0092] In this invention, the photochromic product preferably includes eyeglass lenses, optical lens products, glass products, or electronic consumer products; the optical lens product preferably includes a magnifying lens, a camera lens, or a dimming lens; the glass product preferably includes photochromic laminated glass, photochromic window glass, or photochromic automotive film; and the electronic consumer product preferably includes a display screen, a display back panel, security components, anti-counterfeiting components, decorative products, clothing, or ornaments.
[0093] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.
[0094] 50.8 mmol of methyl 1-bromo-4-methoxy-2-naphthylcarboxylate, 1 mmol of [1,1'-bis(diphenylphosphino)ferrocene]palladium dichloride, 61 mmol of pinacol diborate, 150 g of toluene, 13.5 g of water, and 1.5 g of potassium acetate were mixed. After purging with nitrogen, the mixture was heated to 80 °C and stirred at 200 rpm for 24 h to obtain a mixed solution. The mixed solution was cooled to room temperature and concentrated by rotary evaporation at -0.01 MPa and 50 °C for 30 min to obtain an intermediate product. The intermediate product, 76.2 mmol of 4,7-dibromo-2,1,3-benzothiadiazole, 2 mmol of tetra(triphenylphosphino)palladium, 50 g of potassium carbonate aqueous solution (concentration of potassium carbonate aqueous solution was 2 mol / L), and 250 g of tetrahydrofuran were mixed. After purging with nitrogen, the mixture was heated to 60 °C and stirred at 200 rpm for 18 h to obtain a mixed solution. The mixed solution was poured into 200 mL of 2 mol / L hydrochloric acid and diluted with 500 mL of diethyl ether to obtain the organic layer. The organic layer was washed sequentially with water and 26.5% sodium chloride solution, then dried over anhydrous sodium sulfate, and subsequently concentrated by rotary evaporation at -0.01 MPa and 40 °C for 20 min. The concentrated product was subjected to silica gel column chromatography (silica gel particle size 200–300 mesh) using a 7:3 volume ratio of n-hexane and dichloromethane to give compound C: methyl 1-(7-(bromobenzothiadiazole)-4-methoxy-2-naphthyl acid). Compound C was a yellow crystal with a mass of 16.3 g, and a two-step yield of 75%. Mass spectrometry data: MS (ESI, m / z): [M+H] + calcd for(C 19 H 13 BrN2O3S),429.0; found,429.0.
[0095] 34.9 mmol of methyl 1-(7-(bromobenzothiadiazole)-4-methoxy-2-naphthanoate) and 250 mL of ultra-dry tetrahydrofuran were added to a three-necked flask. The flask was purged with nitrogen. 75 mL of a methyl magnesium bromide ether solution (1 mol / L concentration of methyl magnesium bromide) was added dropwise over 30 min. The mixture was stirred at 200 rpm at 25 °C for 19 h to obtain a mixed solution. This mixed solution was then poured into 200 mL of a 2m3 methyl ether solution. The organic layer was obtained by diluting the solution in 1 mol / L hydrochloric acid with 500 mL of diethyl ether and stirring at 200 rpm for 10 min. The organic layer was washed sequentially with water and 26.5% sodium chloride solution, dried over anhydrous sodium sulfate, and then concentrated by rotary evaporation at -0.01 MPa and 40 °C for 20 min. The concentrated product was subjected to silica gel column chromatography (silica gel particle size 200–300 mesh) with a 6:4 volume ratio of n-hexane and dichloromethane to obtain compound D. Compound D, 100 mL of chloroform, and 14 mmol of p-toluenesulfonic acid pyridine salt were mixed and stirred at 200 rpm for 2 h at 25 °C to obtain a mixed solution. The mixed solution was poured into 500 mL of water and stirred at 200 rpm for 10 min to obtain an organic layer. The organic layer was washed with 26.5% sodium chloride solution, dried over anhydrous sodium sulfate, and then concentrated by rotary evaporation at -0.01 MPa and 40 °C for 20 min. The product was concentrated by rotary evaporation at 40℃ for 30 min. The concentrated product was then subjected to silica gel column chromatography (silica gel particle size 200–300 mesh) using a 95:5 volume ratio of n-hexane and dichloromethane to obtain compound E: 4-bromo-8-methoxy-6,6-dimethyl-6H-indeno[5,6]thiadiazole. Compound E was a pale orange solid with a mass of 7.6 g, and the two-step yield was 53%. Mass spectrometry data: MS (ESI, m / z): [M+H]+calcd for (C 20 H 15 BrN2OS),411.0; found,411.0.
[0096] 18.2 mmol of 4-bromo-8-methoxy-6,6-dimethyl-6H-indeno[5,6]thiadiazole, 0.9 mmol of tris(dibenzylacetone)dipalladium, 36.5 mmol of cesium carbonate, 27.2 mmol of diphenylamine, 250 g of toluene, and 25 g of water were mixed. After purging with nitrogen, the mixture was heated to 100 °C and stirred at 250 rpm for 20 h to obtain a mixed solution. The mixed solution was cooled to room temperature and then poured into 500 mL of water. 80 mL of dichloromethane was added, and the mixture was stirred at 250 rpm for 10 min to obtain an organic layer. The organic layer was washed sequentially with water and a 26.5% sodium chloride solution, then dried with anhydrous sodium sulfate, and subsequently concentrated by rotary evaporation at -0.01 MPa and 40 °C for 20 min. The product, concentrated by rotary evaporation, was subjected to silica gel column chromatography (silica gel particle size 200-300 mesh) using hexane and dichloromethane in a volume ratio of 95:5 to obtain compound G: 8-methoxy-6,6-dimethyl-4-diphenylamino-6H-indeno[5,6]thiadiazole. Compound G was grayish-white, with a mass of 6.1 g and a yield of 67%. Mass spectrometry data: MS (ESI, m / z): [M+H]+calcd for (C 32 H 25 N3OS), 500.6; found, 500.4.
[0097] 12 mmol of 8-methoxy-6,6-dimethyl-4-diphenylamino-6H-indeno[5,6]thiadiazole and 18 mL of chloroform were mixed, and 18 mL of a boron tribromide dichloromethane solution (the concentration of boron tribromide in the dichloromethane solution was 1 mol / L) was added dropwise at a rate of 0.6 mL / min. After the addition was complete, the mixture was stirred at 200 rpm for 20 h at 25 °C to obtain a mixed solution. The mixed solution was poured into 50 mL of saturated sodium bicarbonate solution, and 50 mL of dichloromethane was added. The mixture was stirred at 200 rpm for 10 min to obtain an aqueous layer. The aqueous layer was extracted three times with 50 mL of dichloromethane each time to obtain an organic layer. The organic layer was washed sequentially with water and a 26.5% sodium chloride solution, then dried with anhydrous sodium sulfate, and subsequently concentrated by rotary evaporation at -0.01 MPa and 25 °C for 30 min. The concentrated product was then subjected to silica gel column chromatography (silica gel particle size 200-300 mesh) using a 5:5 volume ratio of n-hexane and dichloromethane to obtain compound H: 8-hydroxy-6,6-dimethyl-4-diphenylamino-6H-indeno[5,6]thiadiazole. Compound H was gray, with a mass of 5 g and a yield of 86%. Mass spectrometry data: MS (ESI, m / z): [M+H]+calcd for (C 31 H 23 N3OS), 486.2; found, 486.1.
[0098] 4.7 mmol of 1-(4-diphenylaminophenyl)-1-phenylprop-2-ynyl alcohol, 3.8 mmol of 8-hydroxy-6,6-dimethyl-4-diphenylamino-6H-indeno[5,6]thiadiazole, and 100 mL of dichloromethane were mixed, followed by the addition of 2.8 mmol of p-toluenesulfonic acid pyridinium salt. The mixture was purged with nitrogen, heated to 40 °C, and stirred at 150 rpm for 6 h to obtain a mixed solution. The mixed solution was poured into 200 mL of ice water and extracted three times with 200 mL of toluene each time to obtain the organic phase. The organic phase was concentrated by rotary evaporation at -0.01 MPa and 40 °C for 20 min. The concentrated product was then subjected to silica gel column chromatography (silica gel particle size 200-300 mesh) using petroleum ether and dichloromethane in a 1:1 volume ratio to obtain the photochromic compound: 3-(4-diphenylaminophenyl)-3-phenyl-13,13-dimethyl-11-diphenylamino-dihydroindenzo[8,9]thiadiazole. The mass of the photochromic compound was 960 mg, the yield was 29%, and the purity was 99.5%. Mass spectrometry data: MS (ESI, m / z): [M+H] + calcd for(C 58 H 42 N4OS), 844.1; found, 844.1. Proton NMR data: 1 H NMR(400MHz, CDCl3)δ8.71(d,1H),8.49(d,1H),8.17(d,1H),7.63(d,1H),7.59–7.49(m,5H),7.43–7.38(m,4H),7 .34-7.30(m,2H),7.29–7.24(m,5H),7.24–7.18(m,6H),7.14–7.06(m,8H),6.89(d,1H),6.28(d,1H),2.10(s,6H).
[0099] Example 2
[0100] In Example 1, methyl 1-bromo-4-methoxy-2-naphthoic acid was replaced with methyl 1-bromo-4,6,7-trimethoxy-2-naphthoic acid, diphenylamine was replaced with 4,4-dimethoxydiphenylamine, and 1-(4-diphenylaminophenyl)-1-phenylprop-2-kynyl alcohol was replaced with 1-(4-di(4-methoxyphenyl)aminophenyl)-1-phenylprop-2-kynyl alcohol, and the rest were the same as in Example 1.
[0101] Mass spectrometry data of the photochromic compound prepared in this embodiment: MS (ESI, m / z): [M+H] + calcd for(C 64 H 54N4O7S),1023.4; found,1023.4.
[0102] The structural formula of the photochromic compound prepared in this embodiment is:
[0103] Example 3
[0104] In Example 2, 4,4-dimethoxydiphenylamine was replaced with 4,4-bis(N,N-dimethylamino)diphenylamine, and everything else was the same as in Example 2.
[0105] Mass spectrometry data of the photochromic compound prepared in this embodiment: MS (ESI, m / z): [M+H] + calcd for(C 66 H 60 N6O5S),1050.3; found,1050.3.
[0106] The structural formula of the photochromic compound prepared in this embodiment is:
[0107] Example 4
[0108] The methyl magnesium bromide in Example 1 was replaced with phenyl magnesium bromide, and everything else was the same as in Example 1.
[0109] Mass spectrometry data of the photochromic compound prepared in this embodiment: MS (ESI, m / z): [M+H] + calcd for(C 68 H 46 N4OS), 967.3; found, 967.3.
[0110] The structural formula of the photochromic compound prepared in this embodiment is:
[0111] Example 5
[0112] In Example 1, 4,7-dibromo-2,1,3-benzothiadiazole was replaced with 4,7-dibromo-2,1,3-benzoxadiazole, and methyl 1-bromo-4-methoxy-2-naphthoic acid was replaced with methyl 1-bromo-4,6,7-trimethoxy-2-naphthoic acid, with the rest being the same as in Example 1.
[0113] Mass spectrometry data of the photochromic compound prepared in this embodiment: MS (ESI, m / z): [M+H]+calcd for(C 62 H 50 N4O6), 947.4; found, 947.4.
[0114] The structural formula of the photochromic compound prepared in this embodiment is:
[0115] Example 6
[0116] In Example 1, 4,7-dibromo-2,1,3-benzothiadiazole was replaced with 4,7-dibromo-2-(n-butyl)-2H-benzo[D][1,2,3]triazole, diphenylamine was replaced with 4,4-diethylaminodiphenylamine, and 1-(4-diphenylaminophenyl)-1-phenylprop-2-kynyl alcohol was replaced with 1-(4-di(4-diethylaminophenyl)aminophenyl)-1-phenylprop-2-kynyl alcohol, and the rest were the same as in Example 1.
[0117] Mass spectrometry data of the photochromic compound prepared in this embodiment: MS (ESI, m / z): [M+H] + calcd for(C 88 H 91 N9O),1290.7; found,1290.7.
[0118] The structural formula of the photochromic compound prepared in this embodiment is:
[0119] Comparative Example 1
[0120] The structural formula of the photochromic compound is:
[0121] Application Example 1
[0122] By weight, 25 parts of polyvinyl butyral resin, 6 parts of dibutyl phthalate, 65 parts of ethyl acetate, 2 parts of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, 1 part of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 0.5 parts of dibutylhydroxytoluene, and 0.5 parts of the photochromic compound prepared in Example 1 were mixed and mechanically stirred at 1000 rpm for 2 hours, followed by standing for 1 hour to obtain a mixture. The mixture was placed in an extruder and extruded at 140°C, then hot-pressed at 140°C and 1.0 MPa to form a film with a thickness of 3.6 μm. After natural cooling to room temperature, a photochromic sandwich film was obtained.
[0123] Take two pieces of transparent white glass, each 10cm x 10cm, place the photochromic interlayer film between the two pieces of transparent white glass, and pre-press them under a roller press (pre-pressing temperature is 70℃, pressure is 0.1MPa) to initially remove air bubbles; then press them at 130℃ and 0.8MPa for 90 minutes to form the shape, and then let them cool naturally to room temperature to obtain laminated double-layer glass.
[0124] Application Comparative Example 1
[0125] Replace the photochromic compound in Application Example 1 with the photochromic compound in Comparative Example 1, and keep everything else the same as in Application Example 1.
[0126] Irradiation tests were conducted on laminated double-glazed glass according to GB / T 5137.3-2020; near-infrared (wavelength range of 780–2500 nm) absorption tests were conducted on laminated double-glazed glass according to ISO 9050:2017. The test results are shown in Table 1.
[0127] Table 1. Irradiation and near-infrared absorption test results of laminated double-glazed glass.
[0128] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A photochromic compound, characterized in that, The structural formula of the photochromic compound is: Among them, R1, R2, R7, and R8 are independently hydrogen, halogen, hydroxyl, alkyl, alkoxy, amino, aryl, or heteroaryl. R3 and R4 are independently hydrogen, halogen, hydroxyl, alkyl, heterocyclic alkyl, alkoxy, aryl, or heteroaryl; R is hydrogen, alkyl, cycloalkyl, or aryl; X is N-R9, O, or S; R9 is hydrogen, alkyl, aryl, or heteroaryl.
2. The photochromic compound according to claim 1, characterized in that, The photochromic compound is any one of the following structural formulas:
3. The method for preparing the photochromic compound according to claim 1 or 2, characterized in that, It includes the following steps: (1) Compound A, [1,1'-bis(diphenylphosphino)ferrocene]palladium dichloride, pinacol diborate, potassium acetate, toluene and water were subjected to the Miyaura borylation reaction to obtain the intermediate product; (2) The intermediate product, compound B, tetra(triphenylphosphine)palladium, potassium carbonate solution and tetrahydrofuran were subjected to a Suzuki coupling reaction to obtain compound C; (3) Compound C, Grignard reagent and tetrahydrofuran are mixed and reacted to obtain compound D; (4) Compound D, p-toluenesulfonic acid pyridinium salt and chloroform were subjected to a cyclization reaction to obtain compound E; (5) Compound E, compound F, tris(dibenzylacetone)palladium, cesium carbonate, toluene and water were cross-coupled to obtain compound G; (6) Compound G, boron tribromide and chloroform were subjected to a demethylation reaction to give compound H; (7) Mix compound H, compound J, p-toluenesulfonic acid pyridine salt and dichloromethane and react to obtain the photochromic compound.
4. The preparation method according to claim 3, characterized in that, The structural formula of compound A in step (1) is as follows: Among them, R3 and R4 are independently hydrogen, halogen, hydroxyl, alkyl, heterocyclic alkyl, alkoxy, aryl or heteroaryl; In step (1), the molar ratio of compound A, [1,1'-bis(diphenylphosphino)ferrocene]palladium dichloride and pinacol diborate is 48-52:1:58-63, and the molar mass ratio of compound A, potassium acetate, toluene and water is 48-52 mmol:1-2 g:120-180 g:10-15 g; the temperature of the Miyaura borylation reaction is 70-90 °C, and the time of the Miyaura borylation reaction is 20-28 h.
5. The preparation method according to claim 3 or 4, characterized in that, The structural formula of compound B in step (2) is as follows: Wherein, X is N-R9, O or S, and R9 is hydrogen, alkyl, aryl or heteroaryl; The molar ratio of compound B in step (2), tetra(triphenylphosphine)palladium, and compound A in step (1) is 75-80:2:48-52; the mass molar ratio of potassium carbonate solution, tetrahydrofuran, and compound A in step (1) is 48-52 g:200-300 g:48-52 mmol; the concentration of potassium carbonate solution is 1.5-2.5 mol / L; the temperature of the Suzuki coupling reaction is 50-70 °C; and the time of the Suzuki coupling reaction is 12-24 h.
6. The preparation method according to claim 5, characterized in that, The Grignard reagent described in step (3) has the structural formula R-Mg-Br, where R is hydrogen, alkyl, cycloalkyl or aryl; In step (3), the molar volume ratio of compound C, Grignard reagent, and tetrahydrofuran is 32–38 mmol: 72–78 mmol: 250 mL; the reaction temperature is 20–30 °C, and the reaction time is 14–24 h. The molar ratio of p-toluenesulfonic acid pyridine salt in step (4) to compound C in step (3) is 12-16:32-38, and the molar volume ratio of p-toluenesulfonic acid pyridine salt to chloroform is 12-16 mmol:100 mL; the cyclization reaction temperature is 20-30 °C, and the cyclization reaction time is 1-3 h.
7. The preparation method according to claim 6, characterized in that, The structural formula of compound F in step (5) is as follows: Among them, R7 and R8 are independently hydrogen, halogen, hydroxyl, alkyl, alkoxy, amino, aryl or heteroaryl; In step (5), the molar ratio of compound E, compound F, tris(dibenzylacetone)palladium, cesium carbonate, toluene, and water is 15–20 mmol: 25–30 mmol: 0.5–1.5 mmol: 34–38 mmol: 250 g: 20–30 g; the temperature of the cross-coupling reaction is 90–110 °C, and the time of the cross-coupling reaction is 16–24 h.
8. The preparation method according to claim 6 or 7, characterized in that, In step (6), the molar volume ratio of compound G, boron tribromide, and chloroform is 10–15 mmol: 15–20 mmol: 10–25 mL; the temperature of the demethylation reaction is 20–30 °C, and the time of the demethylation reaction is 16–24 h.
9. The preparation method according to claim 8, characterized in that, The structural formula of compound J in step (7) is as follows: Among them, R1 and R2 are independently hydrogen, halogen, hydroxyl, alkyl, alkoxy, amino, aryl or heteroaryl; In step (7), the molar volume ratio of compound H, compound J, p-toluenesulfonic acid pyridinium salt and dichloromethane is 2-5 mmol: 3-6 mmol: 1-4 mmol: 100 mL; the reaction temperature is 35-45 °C and the reaction time is 4-10 h.
10. The use of the photochromic compound according to claim 1 or 2 in photochromic articles.