A red light / near-infrared light-induced color-changing molecule, its preparation method and application

Abstract

The present invention discloses a red light / near-infrared light-induced color-changing molecule, a preparation method thereof and an application. Specifically, the present invention discloses a compound shown in Formula I or a stereoisomer thereof. The open and closed ring bodies of the red light / near-infrared light-induced color-changing molecule based on perylene diimide bay region substitution of the present invention have an effectively red-shifted absorption wavelength, can work in multiple cycles, exhibit good anti-fatigue performance, and the closed ring body structure obtained by light irradiation is relatively stable, realizing an efficient open and closed ring process under red light and near-infrared light irradiation, providing new ideas for the design of novel photochromic systems.

Description

Technical Field

[0001] The present invention relates to the field of organic photochromism, and specifically, to a preparation and color-changing method of a novel red light / near-infrared light-responsive photochromic molecule based on perylene diimide bay area substitution. Background Art

[0002] Photochromic molecules can reversibly transform between two isomers with different structural properties under light irradiation. In recent years, photochromic molecules have attracted much attention in the interdisciplinary research fields of chemistry-biology-medicine such as super-resolution imaging, photodynamic therapy, and photopharmacology. Traditional photochromic molecules need to be excited by ultraviolet light to undergo a photochromic reaction. Ultraviolet light excitation has disadvantages such as high energy consumption, high damage, high biological toxicity, and poor tissue penetration. Long-term use of ultraviolet light excitation will cause damage to the performance of photochromic molecules (accumulation of by-products, decreased fatigue resistance) and the corresponding material matrix, resulting in a shortened service life of advanced optical materials based on photochromic molecules. In addition, ultraviolet light is carcinogenic and easily induces gene mutations, leading to apoptosis of cells, which greatly limits the potential applications of diarylethene molecules in emerging interdisciplinary fields such as chemical biology. Although visible light (400 nm - 600 nm) with low energy consumption and low damage meets the application research of in vitro imaging and superficial tissues such as skin, esophagus, and colon, due to strong optical scattering and self-absorption of hemoglobin in the body, the tissue penetration is limited (<0.4 cm), and it cannot meet the light control applications related to deep tissues and living bodies. Red light and near-infrared light (600 nm - 1100 nm) are not easily scattered in tissues and have advantages such as low biological toxicity and strong tissue penetration (~2 cm), and are ideal light sources for high spatiotemporal resolution precise light regulation in deep tissues and living bodies.

[0003] Previously, photochromic molecules based on perylene diimide bay area substitution have been reported (Zhang F, Zhang Z, Deng L, et al. (2023). Green-Light Responsive Perylene Bisimides for Atom-Economic Thiol Generation and Click-Ligation. Organic letters, 25(5), 872–876). However, their excitation wavelength is still limited to 400 nm - 600 nm and the photochromic fatigue resistance is poor. Therefore, designing and synthesizing bidirectional red light / near-infrared light-driven photochromic molecules is of great significance for broadening their practical applications in the interdisciplinary research fields of chemistry-biology-medicine. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the problems of short excitation wavelength and weak tissue penetration of traditional photochromic molecules. For this purpose, the present invention provides a series of bidirectional red light / near-infrared photochromic molecules based on bay-substituted perylene diimides. The absorption wavelengths of the open and closed rings of the photochromic molecules of the present invention are effectively red-shifted, and they can work in multiple cycles, showing good fatigue resistance. Moreover, the closed-ring structure obtained by light irradiation is relatively stable, realizing an efficient open / closed-ring process under red light and near-infrared light irradiation, providing new ideas for the design of new photochromic systems.

[0005] The present invention solves the above technical problems through the following technical solutions.

[0006] The present invention provides a compound of formula I or its stereoisomer:

[0007]

[0008] Wherein,

[0009] R 1 is hydrogen, C1-C6 alkoxy, halogen, cyano, C1-C6 alkyl or C6-C 10 aryl;

[0010] R 2 is hydrogen, C1-C6 alkoxy, halogen, cyano, C1-C6 alkyl or C6-C 10 aryl;

[0011] R 3 is C1-C6 alkoxy, halogen, cyano, C1-C6 alkyl or C6-C 10 aryl;

[0012] R 4-1 is C1-C6 alkoxy, cyano, halogen or C1-C6 alkyl;

[0013] X 1 is S, O, Se, Te, NH or SO2;

[0014] X 2 is CR 4-2 or N;

[0015] X 3 is CR 4-3 or N;

[0016] R 4-2 is C1-C6 alkoxy, halogen, cyano, C1-C6 alkyl, C6-C 10 aryl or C6-C 4-2-1 aryl substituted by one, two or three R 10 aryl;

[0017] R4-3 is H, C1-C6 alkoxy, halogen, cyano, C1-C6 alkyl, C6-C 10 aryl or C6-C 4-3-1 aryl substituted by 1, 2 or 3 R 10 groups;

[0018] Alternatively, R 4-2 and the atom to which it is attached together form a benzene ring, a benzene ring substituted by 1, 2 or 3 R 4-3 groups, a 6-membered heteroaryl "wherein the heteroatoms are selected from 1, 2 or 3 of N, O and S and the number of heteroatoms is 1, 2 or 3" or a 6-membered heteroaryl "wherein the heteroatoms are selected from 1, 2 or 3 of N, O and S and the number of heteroatoms is 1, 2 or 3" substituted by 1, 2 or 3 R a groups; b substituted by 1, 2 or 3 R

[0019] R a and R b are independently halogen, cyano, C1-C6 alkoxy or C 1- C6 alkyl;

[0020] R 4-2-1 and R 4-3-1 are independently halogen, cyano, C1-C6 alkoxy or C 1- C6 alkyl;

[0021] R 5 is optionally substituted by 1, 2 or 3 R 5-1 groups: C1-C 20 alkyl, C3-C6 cycloalkyl or C6-C 10 aryl;

[0022] R 5-1 is C1-C6 alkyl.

[0023] In certain preferred embodiments of the present invention, for the compounds of formula (I) as described above, or certain groups in their stereoisomers, are defined as follows, and the groups not mentioned are the same as those described in any embodiment of the present invention (abbreviated as "in a certain embodiment").

[0024] In a certain embodiment, R 1 is hydrogen or C1-C6 alkoxy.

[0025] In a certain embodiment, R 2 is hydrogen or C1-C6 alkoxy.

[0026] In a certain embodiment, R 3 is C1-C6 alkoxy.

[0027] In a certain embodiment, R4-1 is a C1-C6 alkyl group.

[0028] In one embodiment, X 1 is S, O or SO2.

[0029] In one embodiment, X 2 is CR 4-2 .

[0030] In one embodiment, R 4-2 is a C1-C6 alkyl group, a C6-C 10 aryl group or a C6-C 4-2-1 aryl group substituted by one, two or three Rs 10 , R 4-3 is H, or, R 4-2 and R 4-3 together with the atom to which it is attached form a benzene ring.

[0031] In one embodiment, R 4-2-1 and R 4-3-1 are independently a cyano group or a C1-C6 alkoxy group.

[0032] In one embodiment, R 5 is a C1-C 20 alkyl group, more preferably -CR 5-2 R 5-3 , R 5-2 and R 5-3 are independently C1-C9 alkyl groups.

[0033] In one embodiment, among R 1 , R 2 , R 3 , R 4-2-1 and R 4-3-1 , the C1-C6 alkoxy groups are independently methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy or tert-butoxy, more preferably methoxy.

[0034] In one embodiment, among R 1 , R 2 , R 3 , R 4-1 , R 4-2 , R 4-3 , R a , R b , R 4-2-1 and R 4-3-1 , the halogens are independently fluorine, chlorine, bromine or iodine.

[0035] In one embodiment, R 1 , R 2 , R3 , R 4-3 , R a , R b , R 4-2-1 and R 4-3-1 Among them, the C1-C6 alkyl group is independently methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl.

[0036] In one embodiment, R 1 , R 2 , R 3 , R 4-3 and R 5 Among them, the C6-C 10 aryl group is independently phenyl or naphthyl.

[0037] In one embodiment, R 4-1 and R 4-2 Among them, the C1-C6 alkyl group is independently methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl, preferably methyl.

[0038] In one embodiment, R 4-2 Among them, the C6-C 10 aryl group is independently phenyl or naphthyl, preferably phenyl.

[0039] In one embodiment, R 4-2 , R 4-3 , R a and R b Among them, the C1-C6 alkoxy group is independently methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy or tert-butoxy.

[0040] In one embodiment, R 5 Among them, the C3-C6 cycloalkyl group is cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl.

[0041] In one embodiment, R 5 Among them, the C1-C 20 alkane is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, undecane, dodecane, tridecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, nonadecane or eicosane, preferably undecane or tridecane, more preferably

[0042] In one embodiment, R 5-1Among them, the C1-C6 alkyl group is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl, preferably isopropyl.

[0043] In one embodiment, R 5-2 and R 5-3 Among them, the C1-C9 alkyl group is independently a C4-C6 alkyl group, preferably n-pentyl or n-hexyl.

[0044] In one embodiment, R 1 is hydrogen or methoxy.

[0045] In one embodiment, R 2 is hydrogen or methoxy.

[0046] In one embodiment, R 3 is methoxy.

[0047] In one embodiment, R 4-1 is methyl.

[0048] In one embodiment, R 4-2 is methyl, preferably methyl, R 4-3 is H, methyl, preferably H; alternatively, R 4-2 and R 4-3 together with the atoms to which they are attached form a benzene ring.

[0049] In one embodiment, R 4-2-1 and R 4-2-1 are fluorine, cyano or methoxy, preferably cyano or methoxy.

[0050] In one embodiment, R 5 is preferably

[0051] In one embodiment, preferably

[0052] In one embodiment, the compound represented by Formula I is any of the following compounds:

[0053]

[0054]

[0055] The present invention also provides a method for preparing the compound represented by Formula I as described above, which is any of the following methods:

[0056] Method 1: Compound I-1 reacts with to obtain the compound shown in Formula I through a coupling reaction,

[0057]

[0058] In Method 1, R 1 、R 2 、R 3 、R 5 、X 1 、X 3 and R 4-1 are defined as described in any aspect of the present invention. The conditions and operations of the above reaction can be those common to such reactions in the art;

[0059] Method 2: Compound I-4 reacts with to obtain the compound shown in Formula I through a coupling reaction,

[0060]

[0061] In Method 2, X 2 is CR 4-2 ,R 1 、R 2 、R 3 、X 1 、X 3 、R 4-1 、R 4-2 and R 5 are defined as described in any aspect of the present invention. The conditions and operations of the above reaction can be those common to such reactions in the art;

[0062] Preferably, in Method 2, it further includes the following steps: Step 1, Compound I-1 reacts with to obtain Compound I-2 through a coupling reaction; Step 2, Compound I-2 is deprotected to obtain Compound I-3; Step 3, Compound I-3 reacts with NBS through a bromination reaction to obtain Compound I-4.

[0063]

[0064] Method 3: Compound I-5 is oxidized to obtain the compound shown in Formula I;

[0065]

[0066] In Method 3, X 1 is SO2, R 1 、R 2 、R 3 、X 2 、X 3 、R4-1 , R 4-2 and R 5 are defined as described in any embodiment of the present invention, and the conditions and operations of the above reaction can be those common to such reactions in the art.

[0067] The present invention also provides a compound represented by Formula I-2, I-3, I-4 or I-5:

[0068]

[0069] wherein, R 1 , R 2 , R 3 , X 1 , X 2 , X 3 , R 4-1 , R 4-2 and R 5 are defined as described above.

[0070] The present invention also provides a compound represented by any of the following:

[0071]

[0072]

[0073] The present invention also provides a photochromic material comprising a compound represented by Formula I as described in any of the preceding items or a stereoisomer thereof.

[0074] The present invention also provides an application of a compound represented by Formula I as described above or a stereoisomer thereof in a color-changing material, a biological probe, and a light-controlled drug.

[0075] Unless otherwise specified, the terms used in the present invention have the following meanings:

[0076] Those skilled in the art can understand that, according to the convention used in the art, the used in the structural formula of the group described in the present invention means that the corresponding group is connected to other fragments and groups in the compound through this site.

[0077] When any variable (such as R 4-2-1 ) appears multiple times in the definition of a compound, the definition of each occurrence of this variable is independent of the definition of the remaining occurrences, and their meanings are independent of each other and do not affect each other. Therefore, if a group is substituted by 1, 2 or 3 R 4-2-1 groups, that is to say, this group may be substituted by up to 3 R 4-2-1 , the definition of R 4-2-1 at this position is independent of the definition of R 4-2-1The definitions are independent of each other. Additionally, combinations of substituents and / or variables are permitted only if the combination results in a stable compound.

[0078] The term "A-membered", where A is an integer, generally describes a ring in which the number of ring-forming atoms is A. For example, thienyl is an example of a 5-membered heteroaryl, and pyrimidinyl is an example of a 6-membered heteroaryl.

[0079] The term "A-B-membered", where A and B are integers, describes a ring in which the number of ring-forming atoms ranges from A to B.

[0080] The term "halogen" refers to fluorine, chlorine, bromine, or iodine.

[0081] The term "alkyl" refers to a straight-chain or branched-chain saturated hydrocarbon group having a specified number of carbon atoms. In some embodiments, the alkyl is a C1-C6 alkyl, such as a C1-C5 alkyl, a C1-C4 alkyl, a C1-C3 alkyl, a C1-C2 alkyl, etc. Examples of alkyls include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, isobutyl, sec-butyl, n-pentyl, n-hexyl, and similar alkyls.

[0082] The term "alkoxy" refers to the group -O-R X , where R X is an alkyl as defined above.

[0083] The term "cycloalkyl" refers to a saturated, monocyclic, bridged, or spirocyclic ring group having a specified number of ring carbon atoms (such as C3-C6) and consisting only of carbon atoms in the ring. Monocyclic cycloalkyls include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc.

[0084] On the basis of not violating the common knowledge in the art, the above preferred conditions can be arbitrarily combined to obtain various preferred examples of the present invention.

[0085] The reagents and raw materials used in the present invention are all commercially available.

[0086] The positive and progressive effects of the present invention are as follows: A series of perylene diimide bay area-substituted bidirectional red light / near-infrared photochromic molecules provided by the present invention can effectively redshift the absorption wavelengths of the open and closed rings of the photochromic molecules. The photochromic molecules of the present invention can work in multiple cycles, showing good anti-fatigue properties, and the closed-ring structure obtained by light irradiation is stable, realizing an efficient open / closed-ring process under red light and near-infrared light irradiation, providing new ideas for the design of novel photochromic systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0087] Figure 1 is the change of the absorption spectrum of Compound 4;

[0088] Figure 2 is the anti-fatigue spectrum of Compound 4;

[0089] Figure 3 is the change in the absorption spectrum of Compound 8;

[0090] Figure 4 is the anti-fatigue spectrum of Compound 8;

[0091] Figure 5 is the change in the absorption spectrum of Compound 14;

[0092] Figure 6 is the anti-fatigue spectrum of Compound 14;

[0093] Figure 7 is the change in the absorption spectrum of Compound 15;

[0094] Figure 8 is the anti-fatigue spectrum of Compound 15;

[0095] Figure 9 is the change in the absorption spectrum of Compound 17;

[0096] Figure 10 is the anti-fatigue spectrum of Compound 17;

[0097] Figure 11 is the change in the absorption spectrum of Compound 19;

[0098] Figure 12 is the anti-fatigue spectrum of Compound 19;

[0099] Figure 13 is the change in the absorption spectrum of Compound 20;

[0100] Figure 14 is the anti-fatigue spectrum of Compound 20;

[0101] Figure 15 is the change in the absorption spectrum of Compound 21;

[0102] Figure 16 is the anti-fatigue spectrum of Compound 21. Detailed implementation mode

[0103] The present invention will be further described below by way of examples, but the present invention is not limited to the scope of the described examples. For the experimental methods without specific conditions in the following examples, they are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0104] Example 1: Related synthesis route of the photochromic compound 4

[0105]

[0106] Synthesis of Compound 2

[0107] In a 100 mL two-necked flask, 500 mg (0.59 mmol) of Compound 1 (Henan Bauhinia Chemical Technology Co., Ltd., product number: ZJ1309387-23-2), 1.3 mL of a 5.4 M methanol solution of sodium methoxide, and 6 mL of dichloromethane solution were added, and the mixture was stirred overnight at room temperature. After the reaction was completed, it was washed with 2 M hydrochloric acid (50 mL×3), extracted with dichloromethane (100 mL×3), dried over anhydrous MgSO4, filtered by suction, and the organic solvent was removed by rotary evaporation to obtain a purple-red crude product. The crude product was separated and purified by silica gel column chromatography (petroleum ether:dichloromethane = 1:1) to obtain a dark purple solid Compound 2 (377 mg, 84%).

[0108] 1 H NMR (400 MHz, CDCl3, ppm): δ 9.45 (d, J = 8.2 Hz, 2H), 8.63 - 8.31 (m, 4H), 5.21 (dq, J = 14.3, 7.4, 6.4 Hz, 2H), 4.29 (s, 6H), 2.27 - 2.26 (m, 4H), 1.88 - 1.82 (m, 4H), 1.29 - 1.25 (m, 24H), 0.84 - 0.82 (m, 12H).

[0109] Synthesis of Compound 3

[0110] In a 150 mL sealed bottle, 104 mg (0.137 mmol) of Compound 2, 0.07 mL (1.37 mmol) of liquid bromine, and 6 mL of dichloromethane solution were added, and the mixture was stirred at room temperature for 24 h. After the reaction was completed, the reaction solution was washed successively with saturated Na2S2O3 (50 mL×3), extracted with dichloromethane (100 mL×3), dried over anhydrous MgSO4, filtered by suction, and the organic solvent was removed by rotary evaporation to obtain a purple-red solid crude product. The crude product was separated and purified by silica gel column chromatography (petroleum ether:dichloromethane = 1:2) to obtain a purple-red solid Compound 3 (30 mg, 26%).

[0111] 1 H NMR (400 MHz, CDCl3, ppm): δ 9.26 (dd, J = 23.0, 8.2 Hz, 1H), 8.88 - 8.27 (m, 4H), 5.28 - 5.14 (m, 2H), 4.36 - 4.22 (m, 6H), 2.26 - 2.20 (m, 4H), 1.84 - 1.82 (m, 4H), 1.28 - 1.25 (m, 24H), 0.84 - 0.81 (m, 12H).

[0112] Synthesis of Compound 4

[0113] In a 100 mL Schlenk flask, compound 3 (43 mg, 0.051 mmol), 2,5-dimethylthiopheneboronic acid (20 mg, 0.13 mmol), potassium carbonate (142 mg), tetrahydrofuran (10 mL), water (2 mL), and the catalyst Pd(PPh3)4 (5.6 mg) were successively added. The mixture was frozen and evacuated to remove oxygen three times under dark conditions at -40 °C, and then heated to reflux overnight (80 °C). After the reaction was completed, the mixture was cooled to room temperature, washed successively with saturated brine (50 mL × 3), extracted with dichloromethane (100 mL × 3), dried over anhydrous MgSO4, filtered by suction, and the organic solvent was removed by rotary evaporation to obtain the crude product. The crude product was purified by silica gel column chromatography (petroleum ether:dichloromethane = 1:2) to obtain the photochromic compound 4 (40.3 mg, 91%).

[0114] 1 H NMR (600 MHz, C2D2Cl4, 120 °C, ppm): δ 9.33 (d, J = 8.2 Hz, 1H), 8.68 - 8.47 (m, 3H), 8.20 (s, 1H), 6.65 (s, 1H), 5.24 - 5.20 (m, 2H), 4.34 (s, 3H), 3.71 (s, 3H), 2.49 (s, 3H), 2.30 - 2.28 (m, 4H), 1.99 (d, J = 9.7 Hz, 3H), 1.95 - 1.89 (m, 4H), 1.52 - 1.33 (m, 24H), 0.93 - 0.83 (m, 12H).

[0115] Example 2: Related synthetic route of photochromic compound 8

[0116]

[0117] Synthesis of compound 5

[0118] In a 100 mL Schlenk flask, compound 3 (222 mg, 0.27 mmol), methylsilane boronic acid (103 mg, 0.35 mmol), aqueous potassium carbonate solution (93 mg, 2 mL), tetrahydrofuran (10 mL), water (2 mL), and the catalyst Pd(PPh3)4 (50 mg) were added respectively. The mixture was frozen and evacuated to remove oxygen three times under dark conditions at -40 °C, and then refluxed at 80 °C overnight. After the reaction was completed, the mixture was cooled to room temperature, washed successively with saturated brine (50 mL × 3), extracted with dichloromethane (100 mL × 3), dried over anhydrous MgSO4, filtered by suction, and the organic solvent was removed by rotary evaporation to obtain a purple-red crude product. The crude product was purified by silica gel column chromatography (petroleum ether:dichloromethane = 1:1) to obtain the intermediate compound 5 (196.97 mg, 78.7%).

[0119] 1 1H NMR (600 MHz, C2D2Cl4, 120 °C, ppm): δ 9.30 (d, J = 8.2 Hz, 1H), 8.59 - 8.42 (m, 3H), 8.08 (d, J = 14.6 Hz, 1H), 6.90 (s, 1H), 5.24 - 5.20 (m, 2H), 4.30 (s, 3H), 3.55 (s, 3H), 2.30 - 2.28 (m, 4H), 1.99 (s, 3H), 1.95 - 1.89 (m, 4H), 1.52 - 1.33 (m, 24H), 0.93 - 0.83 (m, 12H), 0.28 (s, 9H).

[0120] Synthesis of Compound 6

[0121] In a 50 mL two-necked flask, the intermediate 5 (40 mg, 0.043 mmol) and Bu4NF (11.9 mg, 0.0456 mmol) were successively added and dissolved in 10 mL of tetrahydrofuran solution. The mixture was stirred at room temperature overnight. After the reaction, the mixture was successively washed with saturated brine (50 mL × 3), extracted with dichloromethane (100 mL × 3), dried over anhydrous MgSO4, filtered by suction, and the organic solvent was removed by rotary evaporation to obtain a purple-red crude product. The crude product was separated and purified by silica gel column chromatography (petroleum ether:dichloromethane = 1:1) to obtain the intermediate 6 (23.4 mg, 63.7%).

[0122] 1 1H NMR (600 MHz, C2D2Cl4, 120 °C, ppm): δ 9.31 (d, J = 8.3 Hz, 1H), 8.60 - 8.45 (m, 3H), 8.09 (d, J = 14.8 Hz, 1H), 7.42 (s, 1H), 6.92 (s, 1H), 5.24 - 5.21 (m, 2H), 4.31 (s, 3H), 3.54 (s, 3H), 2.32 - 2.28 (m, 4H), 1.99 (s, 3H), 1.95 - 1.89 (m, 4H), 1.52 - 1.33 (m, 24H), 0.93 - 0.83 (m, 12H).

[0123] Synthesis of Compound 7

[0124] In a 50 mL two-necked flask, compound 6 (23.4 mg, 0.027 mmol), AcOH (3 mL), and NBS (5.3 mg, 0.030 mmol) were added respectively, dissolved in 5 mL of chloroform, and stirred at room temperature overnight. After the reaction was completed, the mixture was washed successively with NaOH solution (50 mL × 3), saturated brine (50 mL × 3), extracted with dichloromethane (100 mL × 3), dried over anhydrous MgSO4, filtered by suction, and the organic solvent was removed by rotary evaporation to obtain a dark red crude product. The crude product was separated and purified by silica gel column chromatography (petroleum ether:dichloromethane = 2:1) to obtain compound 7 (15.0 mg, 59.5%).

[0125] 1 1H NMR (600 MHz, C2D2Cl4, 120 °C, ppm): δ 9.28 (d, J = 8.0 Hz, 1H), 8.57 - 8.45 (m, 3H), 8.06 (d, J = 14.4 Hz, 1H), 6.88 (s, 1H), 5.23 - 5.18 (m, 2H), 4.28 (s, 3H), 3.53 (s, 3H), 2.27 - 2.24 (m, 4H), 1.96 (s, 3H), 1.95 - 1.89 (m, 4H), 1.52 - 1.33 (m, 24H), 0.91 - 0.83 (m, 12H).

[0126] Synthesis of compound 8

[0127] In a 100 mL Schlenk flask, compound 7 (17.5 mg, 0.0187 mmol), 4-cyanophenylboronic acid (2.63 mg, 0.0225 mmol), aqueous potassium carbonate solution (93 mg, 1 mL), tetrahydrofuran (10 mL), water (2 mL), and catalyst Pd(PPh3)4 (80 mg) were added successively. The mixture was degassed by freeze-pump-thaw (-40 °C) three times under light protection, and then refluxed at 80 °C overnight. After the reaction was completed, the mixture was cooled to room temperature, washed successively with saturated brine (50 mL × 3), extracted with dichloromethane (100 mL × 3), dried over anhydrous MgSO4, filtered by suction, and the organic solvent was removed by rotary evaporation to obtain a crude product. The crude product was separated and purified by silica gel column chromatography (petroleum ether:dichloromethane = 1:2) to obtain the target compound 8 (5 mg, 28%).

[0128] 11H NMR (600 MHz, C2D2Cl4, 120 °C, ppm): δ 9.36 (d, J = 8.0 Hz, 1H), 8.65 - 8.64 (d, J = 8.5 Hz, 1H), 8.60 (s, 1H), 8.55 (s, 1H), 8.18 (s, 1H), 7.68 - 7.64 (m, 4H), 7.32 (m, 1H), 5.26 - 5.21 (m, 2H), 4.36 (s, 3H), 3.69 (s, 3H), 2.33 - 2.28 (m, 4H), 2.20 - 1.97 (m, 7H), 1.39 - 1.36 (m, 24H), 0.97 - 0.93 (m, 12H).

[0129] Example 3: Related synthetic route of photochromic compound 14

[0130]

[0131] Synthesis of compound 10

[0132] In a 100 mL two-necked flask, sodium methoxide solution (1.77 mL, 7.71 mmol, 25% methanol solution by weight), compound 9 (Henan Bauhinia Chemical Technology Co., Ltd., product number: ZJ1309387 - 42 - 5) (1.0 g, 1.29 mmol) were successively added and dissolved in 10 mL of CH2Cl2 solution. After stirring at room temperature for 14 h, the resulting reaction mixture was washed with 2 M hydrochloric acid (50 mL × 3) and saturated brine (50 mL × 3) respectively, and after extraction with CH2Cl2 (100 mL × 3), the organic phases were combined, dried over anhydrous MgSO4, and the solvent was removed by rotary evaporation under reduced pressure to obtain a crude product. The crude product was separated and purified by silica gel column chromatography and eluted with PE / CH2Cl2 = 1 / 1 to obtain a purple-red solid 10 (0.87 g, 92.5%).

[0133] 1 1H NMR (400 MHz, CDCl3) δ 9.57 (d, J = 8.5 Hz, 1H), 8.75 - 8.50 (m, 6H), 5.21 (d, J = 5.7 Hz, 2H), 4.37 (s, 3H), 2.26 (d, J = 9.0 Hz, 4H), 1.93 - 1.80 (m, 4H), 1.34 - 1.22 (m, 24H), 0.83 (tt, J = 4.9, 2.3 Hz, 12H).

[0134] Synthesis of compound 11

[0135] In a 50 mL sealed bottle, compound 10 (0.56 g, 0.77 mmol), liquid bromine (5.5 g, 34.57 mmol), and CH2Cl2 (10 mL) were added, and the mixture was stirred at room temperature for 48 h. After the reaction was completed, nitrogen was bubbled through to remove the excess liquid bromine. The mixture was washed with Na2S2O3 solution (50 mL × 3), saturated brine (50 mL × 3), dried over anhydrous Mg2SO4, and the solvent was removed by rotary evaporation under reduced pressure to obtain the crude product. The crude product was separated and purified by silica gel column chromatography, eluted with PE / CH2Cl2 = 3 / 1, and a purple-red solid 11 (0.52 g, 76.2%) was obtained.

[0136] 1 H NMR (400 MHz, CDCl3) δ 9.42 (dd, J = 28.2, 8.2 Hz, 1H), 8.95 - 8.35 (m, 4H), 5.26 - 5.11 (m, 2H), 4.29 (s, 3H), 2.23 (q, J = 10.8 Hz, 4H), 1.93 - 1.78 (m, 4H), 1.33 - 1.21 (m, 24H), 0.85 (d, J = 7.0 Hz, 12H).

[0137] Synthesis of compound 12

[0138] In a 100 mL two-necked flask, sodium methoxide solution (1.77 mL, 7.71 mmol, 25% methanol solution by weight), compound 11 (0.26 g, 0.30 mmol) were added in sequence and dissolved in 10 mL of CH2Cl2 solution. After stirring at room temperature for 14 h, the resulting reaction mixture was washed with 2 M hydrochloric acid (50 mL × 3), saturated brine (50 mL × 3), extracted with CH2Cl2 (100 mL × 3), the organic phases were combined, dried over anhydrous MgSO4, and the solvent was removed by rotary evaporation under reduced pressure to obtain the crude product. The crude product was separated and purified by silica gel column chromatography, eluted with PE / EA = 20 / 1, and a dark purple solid 12 (53.2 mg, 23%) was obtained.

[0139] 1 H NMR (400 MHz, CDCl3) δ 9.25 (d, J = 8.3 Hz, 1H), 8.59 - 8.33 (m, 4H), 5.22 (dq, J = 9.7, 4.8 Hz, 2H), 4.30 - 4.22 (m, 9H), 2.27 (dq, J = 12.4, 8.4, 7.6 Hz, 4H), 1.84 (s, 4H), 1.27 (s, 24H), 0.83 (td, J = 7.0, 2.8 Hz, 12H).

[0140] Synthesis of compound 13

[0141] In a 30 mL sealed bottle, compound 12 (36 mg, 0.046 mmol), liquid bromine (72.9 mg, 0.46 mmol), and CH2Cl2 (5 mL) were added respectively, and the mixture was stirred at room temperature for 6 h. After the reaction was completed, nitrogen was bubbled through to remove the excess liquid bromine. The mixture was washed with Na2S2O3 (50 mL × 3), saturated brine (100 mL × 3), dried over anhydrous MgSO4, and the solvent was removed by rotary evaporation under reduced pressure to obtain the crude product. The crude product was separated and purified by silica gel column chromatography, eluted with PE / EA = 30 / 1, and a dark purple solid 13 (15 mg, 75.8%) was obtained.

[0142] 1 H NMR (400 MHz, CDCl3) δ 8.53 (d, J = 19.6 Hz, 1H), 8.45 - 8.27 (m, 3H), 5.21 (dq, J = 9.8, 5.0 Hz, 2H), 4.29 - 4.22 (m, 9H), 2.33 - 2.22 (m, 4H), 1.89 - 1.77 (m, 4H), 1.36 - 1.23 (m, 24H), 0.85 (dt, J = 7.1, 3.6 Hz, 12H).

[0143] Synthesis of compound 14

[0144] In a 100 mL Schlenk tube, compound 13 (15 mg, 0.017 mmol), (2,5 - dimethyl - 3 - thienyl)-boronic acid (3.5 mg, 0.022 mmol), Pd(PPh3)4 (30 mg, 0.02 mmol), aqueous potassium carbonate solution (100 mg, 1 mL), ultra - dry THF (4 mL), and water (1 mL) were added. The mixture was degassed by freeze - pumping (-40 °C) three times under light - shielding conditions, and then refluxed at 80 °C overnight. After the reaction was completed, the mixture was cooled to room temperature, washed with saturated brine (50 mL × 3), extracted with dichloromethane (100 mL × 3), dried over anhydrous MgSO4, filtered, and the organic solvent was removed by rotary evaporation to obtain the crude product. The crude product was separated and purified by silica gel column chromatography (petroleum ether:dichloromethane = 2:1), and a dark purple solid 14 (6.3 mg, 41.5%) was obtained.

[0145] 11H NMR (400 MHz, CDCl3) δ 8.54 - 8.32 (m, 3H), 8.02 (d, J = 15.2 Hz, 1H), 7.04 (d, J = 32.1 Hz, 1H), 5.21 (s, 2H), 4.24 (d, J = 9.4 Hz, 6H), 3.59 (s, 3H), 2.54 (s, 3H), 2.24 (dd, J = 17.9, 10.4 Hz, 4H), 2.13 - 1.96 (m, 3H), 1.82 (s, 4H), 1.28 - 1.23 (m, 24H), 0.85 (d, J = 10.6 Hz, 12H).

[0146] Example 4: Related synthesis route of photochromic compound 15

[0147]

[0148] In a 100 mL Schlenk flask, successively add compound 3 (43 mg, 0.051 mmol), 2 - methyl - 5 - benzyloxyfuran boronic acid (31 mg, 0.13 mmol), potassium carbonate (142 mg), tetrahydrofuran (10 mL), water (1 mL), and catalyst Pd(PPh3)4 (5.6 mg). The mixture is freeze - evacuated to remove oxygen 3 times under dark and - 40 °C conditions, and then heated to reflux overnight (80 °C). After the reaction is completed, wait for the mixture to cool to room temperature, wash successively with saturated brine (50 mL × 3), extract with dichloromethane (100 mL × 3), dry over anhydrous MgSO4, filter by suction, and rotary evaporate to remove the organic solvent to obtain the crude product. The crude product is separated and purified by silica gel column chromatography (petroleum ether:dichloromethane = 1:2) to obtain photochromic compound 4 (41 mg, 85%).

[0149] 1 1H NMR (400 MHz, CDCl3) δ 9.35 - 9.33 (d, J = 8.0 Hz, 1H), 8.63 - 8.62 (m, 2H), 8.53 (s, 1H), 8.20 (s, 1H), 7.49 (m, 2H), 7.10 - 6.95 (m, 3H), 5.21 (s, 2H), 4.24 (d, J = 9.4 Hz, 6H), 3.59 (s, 3H), 2.24 (dd, J = 17.9, 10.4 Hz, 4H), 2.13 - 1.96 (m, 3H), 1.82 (s, 4H), 1.28 - 1.23 (m, 24H), 0.85 (d, J = 10.6 Hz, 12H).

[0150] Example 5: Synthesis route of photochromic compound 17

[0151]

[0152] Synthesis of Compound 16

[0153] In a 100 mL Schlenk flask, compound 3 (43 mg, 0.051 mmol), 2-methyl-5-phenylthiopheneboronic acid (29 mg, 0.13 mmol), potassium carbonate (142 mg), tetrahydrofuran (10 mL), water (2 mL), and the catalyst Pd(PPh3)4 (6.5 mg) were successively added. The mixture was freeze-pumped to remove oxygen three times under light protection and at -40 °C, and then heated to reflux overnight (80 °C). After the reaction was completed, the mixture was cooled to room temperature, washed successively with saturated brine (50 mL × 3), extracted with dichloromethane (100 mL × 3), dried over anhydrous MgSO4, filtered by suction, and the organic solvent was removed by rotary evaporation to obtain the crude product. The crude product was separated and purified by silica gel column chromatography (petroleum ether:dichloromethane = 1:2) to obtain intermediate 16 (12 mg, 83%).

[0154] 1 H NMR (400 MHz, CDCl3) δ 9.35 - 9.32 (d, J =, 1H), 8.64 - 8.62 (m, 2H), 8.54 (s, 1H), 8.18 (s, 1H), 7.49 (m, 2H), 7.10 - 6.93 (m, 3H), 5.20 (s, 2H), 4.21 (d, J = 9.4 Hz, 6H), 3.60 (s, 3H), 2.24 (dd, J = 17.9, 10.4 Hz, 4H), 2.13 - 1.94 (m, 3H), 1.82 (s, 4H), 1.28 - 1.23 (m, 24H), 0.85 (d, J = 10.6 Hz, 12H). Synthesis of Compound 17

[0155] In a 50 mL two-necked flask, compound 16 (43 mg, 0.046 mmol), 30% hydrogen peroxide (1 mL), and dichloromethane (10 mL) were successively added. The mixture was reacted overnight under light protection and at room temperature. After the reaction was completed, it was washed successively with saturated sodium bicarbonate solution (50 mL × 3), extracted with dichloromethane (100 mL × 3), dried over anhydrous MgSO4, filtered by suction, and the organic solvent was removed by rotary evaporation to obtain the crude product. The crude product was separated and purified by silica gel column chromatography (petroleum ether:ethyl acetate = 1:2) to obtain the photochromic compound 17 (22 mg, 52%).

[0156] 11H NMR (400 MHz, CDCl3) δ 9.43 - 9.41 (d, J = 8.2 Hz, 1H), 8.68 - 8.67 (d, J = 8.2 Hz, 1H), 8.61 (s, 2H), 8.38 (s, 1H), 7.78 (d, J = 7.0 Hz, 2H), 7.53 - 7.51 (m, 3H), 6.95 (s, 1H), 5.21 (s, 2H), 4.24 (s, 3H), 3.59 (s, 3H), 2.24 (dd, J = 17.9, 10.4 Hz, 4H), 2.13 - 1.96 (m, 3H), 1.82 (s, 4H), 1.28 - 1.23 (m, 24H), 0.85 (d, J = 10.6 Hz, 12H).

[0157] Comparative Example 1: Synthetic Route of Compound 19

[0158]

[0159] Synthesis of Compound 18

[0160] The sodium methoxide solution (0.161 mL, 0.702 mmol, 25% methanol solution by weight) was added to a solution of Compound 1 (100 mg, 0.117 mmol) in CH2Cl2 (10 mL). The mixture was stirred at room temperature for 14 h. The resulting reaction mixture was washed with 2 M hydrochloric acid and saturated brine (50 mL × 3) respectively. Then it was extracted with CH2Cl2 (100 mL × 3), the organic phases were combined, dried over anhydrous MgSO4, and the solvent was removed by rotary evaporation under reduced pressure to obtain a crude product. The crude product was separated and purified by silica gel column chromatography, eluted with PE / CH2Cl2 = 3 / 2 to obtain red solid 18 (59.8 mg, 63.4%).

[0161] 1 1H NMR (400 MHz, CDCl3) δ 9.57 (d, J = 8.2 Hz, 1H), 9.38 (d, J = 8.2 Hz, 1H), 8.91 (d, J = 12.3 Hz, 1H), 8.73 - 8.45 (m, 3H), 5.19 (q, J = 7.8 Hz, 2H), 4.33 (s, 3H), 2.25 (h, J = 7.9, 7.3 Hz, 4H), 1.85 (dq, J = 14.3, 5.2 Hz, 4H), 1.33 - 1.21 (m, 24H), 0.84 (d, J = 7.1 Hz, 12H).

[0162] Synthesis of Compound 19

[0163] In a 200 mL Schlenk tube, add compound 18 (0.10 g, 0.12 mmol), (2-methyl-5-(4-methoxyphenyl)-3-thienyl)boronic acid (39.99 mg, 0.16 mmol), Pd(PPh3)4 (0.05 g, 0.04 mmol), tetrahydrofuran (10 mL), K2CO3 (160 mg), and water (2 mL). After deoxygenation, heat the mixture under reflux in the dark for 12 h. Cool to room temperature, extract the reaction mixture with CH2Cl2 (100 mL × 3), wash with saturated brine (50 mL × 3), dry over anhydrous MgSO4, remove the solvent by rotary evaporation under reduced pressure to obtain the crude product. Purify the crude product by silica gel column chromatography, eluting with PE / CH2Cl2 = 2 / 1 to obtain a purple-red solid 19 (80.08 mg, 71.7%).

[0164] 1 H NMR (400 MHz, CDCl3) δ 9.35 - 9.33 (d, J =, 1H), 8.63 - 8.62 (m, 2H), 8.53 (s, 1H), 8.20 (s, 1H), 7.49 (m, 2H), 7.10 - 6.95 (m, 3H), 5.21 (s, 2H), 4.24 (s, 3H), 3.59 (s, 3H), 2.24 (dd, J = 17.9, 10.4 Hz, 4H), 2.13 - 1.96 (m, 3H), 1.82 (s, 4H), 1.28 - 1.23 (m, 24H), 0.85 (d, J = 10.6 Hz, 12H).

[0165] Example 6: Synthetic route of photochromic compound 20

[0166]

[0167] Synthesis of compound 20

[0168] In a 100 mL Schlenk flask, successively add compound 3 (43 mg, 0.051 mmol), 2-methyl-5-phenylthiazoleboronic acid (29 mg, 0.13 mmol), potassium carbonate (142 mg), tetrahydrofuran (10 mL), water (1 mL), and catalyst Pd(PPh3)4 (6.5 mg). Freeze-pump-thaw the mixture under dark conditions at -40 °C for 3 times, and then heat under reflux overnight (80 °C). After the reaction is completed, cool the mixture to room temperature, wash successively with saturated brine (50 mL × 3), extract with dichloromethane (100 mL × 3), dry over anhydrous MgSO4, filter by suction, and remove the organic solvent by rotary evaporation to obtain the crude product. Purify the crude product by silica gel column chromatography (petroleum ether:dichloromethane = 1:2) to obtain intermediate 20 (10 mg, 69%).

[0169] 11H NMR (400 MHz, CDCl3) δ 9.35 - 9.32 (d, J=, 1H), 8.64 - 8.62 (m, 2H), 8.54 (s, 1H), 8.18 (s, 1H), 7.49 (m, 2H), 7.10 - 6.93 (m, 2H), 5.20 (s, 2H), 4.21 (d, J=9.4 Hz, 6H), 3.60 (s, 3H), 2.24 (dd, J=17.9, 10.4 Hz, 4H), 2.13 - 1.94 (m, 3H), 1.82 (s, 4H), 1.28 - 1.23 (m, 24H), 0.85 (d, J=10.6 Hz, 12H).

[0170] Example 7: Synthetic Route of Photochromic Compound 21

[0171]

[0172] Synthesis of Compound 21

[0173] In a 100 mL Schlenk flask, compound 3 (43 mg, 0.051 mmol), 2-methylbenzo[b]thiophene-5-boronic acid (25 mg, 0.13 mmol), potassium carbonate (142 mg), tetrahydrofuran (10 mL), water (2 mL), and catalyst Pd(PPh3)4 (6.5 mg) were added successively. The mixture was frozen and evacuated to remove oxygen 3 times under dark conditions at -40 °C, and then heated to reflux overnight (80 °C). After the reaction was completed, the mixture was cooled to room temperature, washed successively with saturated brine (50 mL × 3), extracted with dichloromethane (100 mL × 3), dried over anhydrous MgSO4, filtered by suction, and the organic solvent was removed by rotary evaporation to obtain the crude product. The crude product was purified by silica gel column chromatography (petroleum ether:dichloromethane = 1:2) to obtain intermediate 21 (23 mg, 49%).

[0174] 1 1H NMR (400 MHz, CDCl3) δ 8.42 - 8.40 (d, J=8.6 Hz, 1H), 8.25 (s, 1H), 8.12 - 8.10 (m, 1H), 8.01 - 7.99 (d, J=8.6 Hz, 1H), 7.76 - 7.74 (m, 1H), 7.50 - 7.74 (m, 1H), 7.45 - 7.42 (s, 1H), 7.24 (s, 1H), 7.21 (s, 1H), 5.19 (m, 2H), 4.24 (s, 3H), 3.59 (s, 3H), 2.24 (dd, J=17.9, 10.4 Hz, 4H), 2.13 - 1.96 (m, 3H), 1.82 (s, 4H), 1.28 - 1.23 (m, 24H), 0.85 (d, J=10.6 Hz, 12H).

[0175] Example 8: Photochromic Performance of Compound 4

[0176] Take 8.7 mg of the prepared Compound 4 and dissolve it in 500 mL of toluene solution. The concentration of the resulting solution is 10 μM. Take 3.5 mL of the above solution and place it in a quartz cuvette for ultraviolet absorption test (UV-2600, SHIMADZU). Use an LED with a wavelength of 610 nm to irradiate the solution. The absorption peak at 586 nm gradually decreases, and at the same time, new absorption peaks appear at 650 - 900 nm, with the maximum absorption wavelength at 709 nm. The color of the compound solution gradually changes from the initial purplish red to gray, indicating that the photochemical cyclization reaction has occurred. After 10 minutes of illumination, the absorption spectrum no longer changes and reaches the photostationary state. Use an LED with a wavelength of 730 nm to irradiate the solution, and the absorption spectrum gradually returns to the initial state, and the solution color also changes from gray to the initial state. By alternately using 610 nm / 730 nm LED illumination, the compound can work in multiple cycles. After 20 cycles, it shows obvious anti-fatigue properties ( Figure 1-2 ).

[0177] Example 9: Photochromic Performance of Compound 8

[0178] Prepare the solution and test the photochromic performance according to the method of Example 8. Compared with Compound 4, after irradiation with red light at 610 nm, the absorption peak at the maximum absorption wavelength of 584 nm of Compound 8 gradually decreases, and at the same time, new absorption peaks appear at 650 - 1000 nm, with the maximum absorption wavelength at 745 nm. The color of the compound solution gradually changes from the initial purplish red to gray, indicating that the photochemical cyclization reaction has occurred. After 8 minutes of illumination, the absorption spectrum no longer changes and reaches the photostationary state. Use an LED with a wavelength of 730 nm to irradiate the solution, and the absorption spectrum gradually returns to the initial state, and the solution color also changes from gray to the initial state. By alternately using 610 nm / 730 nm LED illumination, the compound can work in multiple cycles. After 20 cycles, it shows obvious anti-fatigue properties ( Figure 3-4 ).

[0179] Example 10: Photochromic Performance of Compound 14

[0180] Prepare the solution and test the photochromic performance according to the method of Example 8. Compared with Compound 4 (open-ring form λ max = 586 nm), the maximum absorption wavelength of Compound 14 is red-shifted by 19 nm and is located at 605 nm, which is the longest record of the absorption wavelength of the open-ring form in the present invention. After irradiating with 610 nm red light for 7 minutes, the photostationary state is reached, and the maximum absorption wavelength of the closed-ring form is at 763 nm. By alternately using 610 nm / 730 nm LED illumination, the compound also shows good anti-fatigue properties ( Figure 5-6 ).

[0181] Example 11: Photochromic Property of Compound 15

[0182] The solution preparation and photochromic property test were carried out according to the method of Example 8. Compared with Compound 4, the maximum absorption wavelength of Compound 15 was at 588 nm. After irradiation with red light at 610 nm, the solution changed from the initial blue to green. After 11 min of illumination, the solution reached a photostable state, and the maximum absorption wavelength of the obtained closed-ring form was at 777 nm, achieving the longest red shift in the absorption of the closed-ring form in the present invention. By alternately using 610 nm / 730 nm LED illumination, the compound also showed good fatigue resistance( Figure 7-8 ).

[0183] Example 12: Photochromic Property of Compound 17

[0184] The solution preparation and photochromic property test were carried out according to the method of Example 8. The maximum absorption wavelength of Compound 17 was at 588 nm. After irradiation with red light at 610 nm, the solution changed from purple to dark green, and reached a photostable state after 5 min. The maximum absorption wavelength of the obtained closed-ring form was at 621 nm. By alternately using 610 nm / 730 nm LED illumination, the compound also showed good fatigue resistance( Figure 9-10 ).

[0185] The closed-ring form of Compound 17 (shown as Formula 17-c below) had extremely strong stability, and its NMR could be separated by using traditional column chromatography. The specific method was as follows:

[0186]

[0187] 30 mg of the compound was dissolved in 10 mL of dichloromethane solvent, and the solution was irradiated with 610 nm LED for 1 h (power was 30 W, illumination distance was 10 cm). After the reaction, the organic solvent was removed by rotary evaporation to obtain a crude product. The crude product was separated and purified by silica gel column chromatography (petroleum ether:dichloromethane = 1:5) to obtain Compound 17-c (23 mg, 77%).

[0188] 11H NMR (400 MHz, CDCl3) δ 9.67 - 9.66 (d, J = 9.2 Hz, 1H), 8.62 - 8.60 (d, J = 9.2 Hz, 1H), 8.36 (s, 1H), 8.30 - 8.27 (d, J = 19.1 Hz, 2H), 7.95 (s, 1H), 7.62 (s, 2H), 7.15 (s, 1H), 6.98 - 6.96 (m, 2H), 5.19 (m, 2H), 3.36 (s, 3H), 2.66 (s, 3H), 2.57 - 2.42 (m, 4H), 1.89 - 1.86 (m, 4H), 1.50 (s, 3H), 1.28 - 1.23 (m, 24H), 0.85 (d, J = 10.6 Hz, 12H).

[0189] Example 13: Photochromic Property of Compound 20

[0190] The solution was prepared and the photochromic property was tested according to the method of Example 8. Compared with Compound 4, the maximum absorption wavelength of Compound 20 was at 587 nm. After irradiation with red light at 610 nm, the solution changed from purple to brown and reached the photostationary state after 5.5 min. The maximum absorption wavelength of the obtained closed-ring form was at 753 nm. When irradiated with light at 730 nm, the solution gradually returned to the initial state. When alternately irradiated with 610 nm / 730 nm LED light, the compound also showed good fatigue resistance ( Figure 13-14 ).

[0191] Example 14: Photochromic Property of Compound 21

[0192] The solution was prepared and the photochromic property was tested according to the method of Example 8. Compared with Compound 4, the maximum absorption wavelength of Compound 21 was at 587 nm. After irradiation with red light at 610 nm, the solution changed from dark purple to green and reached the photostationary state after 7 min. The maximum absorption wavelength of the obtained closed-ring form was at 621 nm. When irradiated with light at 695 nm, the solution gradually returned to the initial state. When alternately irradiated with 610 nm / 695 nm LED light, the compound also showed good fatigue resistance ( Figure 15-16 )

[0193] Comparative Example 2: Photochromic Property of Compound 19

[0194] The solution was prepared and the photochromic property was tested according to the method of Example 8. Compared with Compound 4, the maximum absorption wavelength of Compound 19 was at 562 nm. After irradiation with green light at 560 nm, a new absorption peak appeared at 671 nm in the absorption spectrum, indicating that the ring-closure reaction occurred. However, as the irradiation continued, the absorption peak at 671 nm gradually decreased, and no obvious isosbestic point was presented in the spectrum, showing poor photochromic fatigue resistanceFigure 11-12 )。

[0195] The preferred embodiments of the present invention have been specifically described above. However, the present invention is not limited to the described embodiments. Those skilled in the art can make various equivalent variations or substitutions without departing from the spirit of the present invention, and these equivalent variations or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A compound represented by Formula I: Wherein, R 1 is hydrogen, a C1-C6 alkoxy group or a C1-C6 alkyl group; R 2 is hydrogen, a C1-C6 alkoxy group or a C1-C6 alkyl group; R 3 is methoxy; R 4-1 is methyl; X 1 is S, O, NH or SO2; X 2 is CR 4-2 ; X 3 is CR 4-3 or N; R 4-2 is a C1-C6 alkoxy group, a C1-C6 alkyl group, a C6-C 10 aryl group or a C6-C 4-2-1 aryl group substituted by one, two or three R 10 groups; R 4-3 is H, C1-C6 alkoxy or C1-C6 alkyl; Alternatively, R 4-2 and R 4-3 together with the atoms connected thereto form a benzene ring or "a 6-membered heteroaryl group in which the heteroatom is selected from 1, 2, or 3 of N, O, and S, and the number of heteroatoms is 1, 2, or 3"; R 4-2-1 independently a halogen, cyano, C1-C6 alkoxy or C 1- C6 alkyl; R 5 is -CR 5-2 R 5-3 ,R 5-2 and R 5-3 are independently C1 - C9 alkyl groups.

2. The compound of formula I as claimed in claim 1, characterized in that, It satisfies one or more of the following conditions: (1)R 1 is hydrogen or a C1-C6 alkoxy group; (2)R 2 is hydrogen or a C1-C6 alkoxy group; (3)X 1 is S, O or SO2; (4)R 4-2 is a C1-C6 alkyl group, a C6-C 10 aryl group or a C6-C 4-2-1 aryl group substituted by one, two or three R 10 groups, R 4-3 is H, or, R 4-2 and R 4-3 together with the atoms to which it is attached form a benzene ring; and (5)R 4-2-1 Independently a cyano group or a C1-C6 alkoxy group.

3. The compound of formula I as described in claim 1, characterized in that, It satisfies one or more of the following conditions: (1)R 1 、R 2 and R 4-2-1 wherein the C1-C6 alkoxy group is independently methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy or tert-butoxy; (2)R 4-2-1 wherein the halogen is independently fluorine, chlorine, bromine or iodine; (3)R 1 、R 2 、R 4-3 and R 4-2-1 wherein the C1-C6 alkyl groups are independently methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl; (4)R 4-2 wherein the C1-C6 alkyl group is independently methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl; (5)R 4-2 wherein the C6-C 10 aryl is independently phenyl or naphthyl; and (6)R 4-2 and R 4-3 wherein the C1-C6 alkoxy group is independently methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy or tert-butoxy; and (7)R 5-2 and R 5-3 wherein the C1-C9 alkyl is independently a C4-C6 alkyl.

4. The compound of formula I as claimed in claim 3, wherein It satisfies one or more of the following conditions: (1)R 1 , R 2 and R 4-2-1 In the above, the C1-C6 alkoxy groups are independently methoxy groups; (2)R 4-2 wherein the C1-C6 alkyl group is independently methyl; (3)R 4-2 Among them, the C6-C 10 aryl groups are independently phenyl; and (4)R 5-2 and R 5-3 wherein the C1-C9 alkyl group is independently a n-pentyl group or a n-hexyl group.

5. The compound of formula I as claimed in claim 1, characterized in that, It satisfies one or more of the following conditions: (1)R 1 is hydrogen or methoxy; (2)R 2 is hydrogen or methoxy; (3)R 4-2 is methyl, R 4-3 is H or methyl; or, R 4-2 and R 4-3 together with the atoms to which it is attached form a benzene ring; (4)R 4-2-1 is fluorine, a cyano group or a methoxy group; and (5) R5 is 6. The compound of formula I as claimed in claim 5, wherein, It satisfies one or two of the following conditions: (1)R 4-2 is methyl, R 4-3 is H; (2)R 4-2-1 is cyano or methoxy; and (3) R5 is 7. The compound represented by Formula I according to claim 1, characterized in that, For 8. The compound of formula I as claimed in claim 1, characterized in that, The compound represented by Formula I is any one of the following compounds:

9. A preparation method of a compound represented by Formula I, which is any one of the following methods: Method 1: Compound I-1 reacts with to obtain the compound shown by Formula I through a coupling reaction. In Method 1, R 1 , R 2 , R 3 , R 5 , X 1 , X 3 and R 4-1 are defined as described in any one of claims 1 - 7; Method 2: Compound I-4 reacts with to obtain the compound shown in Formula I through a coupling reaction. In Method 2, X 2 is CR 4-2 , and the definitions of R 1 , R 2 , R 3 , X 1 , X 3 , R 4-1 , R 4-2 and R 5 are as described in any one of claims 1-7; Method three: Compound I-5 is subjected to an oxidation reaction to obtain the compound represented by Formula I; In Method 3, X 1 is SO2, and R 1 , R 2 , R 3 , X 2 , X 3 , R 4-1 , R 4-2 and R 5 are defined as described in any one of claims 1-7.

10. The preparation method of the compound shown in Formula I as described in Claim 9, characterized in that, In the second method, the following steps are further included: Step 1, compound I-1 reacts with to obtain compound I-2 through a coupling reaction; Step 2, the protecting group of compound I-2 is removed to obtain compound I-3; Step 3, compound I-3 reacts with NBS through a bromination reaction to obtain compound I-4; 11. A compound represented by Formula I-2, I-3, I-4 or I-5: Among them, R 1 、R 2 、R 3 、X 1 、X 2 、X 3 、R 4-1 、R 4-2 and R 5 are defined as described in claim 9.

12. A compound represented by any one of the following:

13. A photochromic material, which comprises the compound represented by Formula I according to any one of claims 1-8.

14. Use of the compound represented by Formula I according to any one of claims 1-8 in the preparation of a color-changing material, a biological probe or a light-controlled drug.

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