Synthetic method of xanthene dye

Abstract

The invention discloses a xanthene dye synthesis method, which comprises: (1) in the presence of an alkali and a catalyst, carrying out an esterification reaction on a hydroxyl group on sulfonyl fluorescein by using an esterification reagent to obtain an intermediate A; and (2) in the presence of alkali and a nickel catalyst, carrying out C-N bond coupling reaction on the intermediate A and an amine compound to obtain the target xanthene dye 2. According to the synthesis method of the xanthene dye, the situation that in a traditional synthesis method, sulfonyl fluorescein needs to be chlorinated through a strong-acidity and strong-corrosivity chlorination reagent such as phosphorus oxychloride or phosphorus pentachloride or thionyl chloride is avoided, generation of a large amount of strong-acidity gas is reduced, corrosion to production equipment is reduced, and the production cost is reduced. And the nickel-catalyzed C-N coupling reaction conditions are mild, the reaction temperature is greatly reduced, the energy consumption is reduced, and the synthesis method is more suitable for large-scale industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of color filters, and particularly relates to a synthesis method of xanthene dyes. Background Art

[0002] A color liquid crystal display device allows white light from a backlight to pass through the above-mentioned color filter to be colored, and displays a color image on the screen. Therefore, high transparency is required as a basic performance of the color filter. For traditional pigment-based color pastes, due to the poor solubility of pigment molecules, they often exist in the photoresist in the form of clusters with relatively large sizes, which will cause scattering of the backlight source, resulting in a decrease in the contrast of the color filter and making it difficult to meet the requirements of new color liquid crystal display devices with higher performance.

[0003] Compared with pigments, dye molecules have high solubility and often dissolve in the photoresist solvent in molecular form. Therefore, there is no scattering phenomenon and the transmittance is high. Based on this, companies in Japan, South Korea and other countries have gradually developed new color photoresist color pastes containing dyes, such as LG in South Korea, Mitsubishi in Japan, etc.

[0004] Xanthene dyes are a class of dyes with dibenzopyran or xanthene structures, mainly including fluorescein (Fluorescein) and rhodamine (Rhodamine). Among them, fluorescein (Fluorescein) was first synthesized by von Baeyer in 1871, while rhodamine B was first successfully synthesized by Noelting and Dziewonski in 1905.

[0005] Xanthene dyes often have strong fluorescence, cover a relatively wide spectral range from yellow to blue-red, and have excellent photophysical properties, such as high molar extinction coefficient, high fluorescence quantum yield, high stability, convenient synthesis and easy modification. Therefore, they can be applied in color photoresist color pastes to improve related properties. For example, the blue photoresist developed by Sumitomo Corporation in Japan contains xanthene dyes.

[0006] Currently, the preparation of such rhodamine-based xanthene dye compounds often adopts the following synthesis method, and the route is as follows: ; The first step reaction of this synthesis route is the chlorination reaction of sulfonyl fluorescein 1. Different reported chlorinating reagents and specific reaction conditions are different; subsequently, under different reaction conditions, the amination reaction is carried out on chlorosulfonyl fluorescein 3 to obtain the target xanthene dye 2.

[0007] Although there are many reports on the preparation method of the target xanthene dye 2, the current manufacturing methods have the following problems respectively: (1) Sulfonyl fluorescein 3 is a key intermediate for preparing the final aminated product. Previous manufacturing methods often used chlorinating reagents such as thionyl chloride, phosphorus oxychloride, and phosphorus pentachloride to chlorinate sulfonyl fluorescein 1. The chlorinating reagents used in this step are all strongly acidic and corrosive, and have high requirements for equipment. (2) The yield of the above chlorination reaction is relatively low (about 30%), and the by-products of the chlorination reaction contain hydrochloric acid gas. The post-treatment process is complex, unfriendly to the environment, and the production cost is relatively high. (3) For the amination reaction of sulfonyl fluorescein 3, relatively harsh conditions are required, such as a high temperature of about 150 °C, and a large excess of amine (10-fold equivalent) is required, which greatly increases the production cost and the difficulty of post-treatment.

[0008] From the above analysis, it can be seen that the current methods for preparing the target xanthene dye all have corresponding problems, so they need to be improved urgently. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to overcome the technical defects of the background technology and provide a synthesis method of xanthene dye. The present invention provides a more efficient and lower-cost method for preparing the target xanthene dye. The synthesis method of xanthene dye of the present invention avoids the need to first chlorinate sulfonyl fluorescein with strongly acidic and corrosive chlorinating reagents such as phosphorus oxychloride, phosphorus pentachloride or thionyl chloride in the traditional synthesis method, which not only reduces the generation of a large amount of strongly acidic gases, but also reduces the corrosion of production equipment. Moreover, the nickel-catalyzed C-N coupling reaction has mild conditions, greatly reduces the reaction temperature, reduces energy consumption, and makes this synthesis method more suitable for large-scale industrial production.

[0010] The technical solutions adopted by the present invention to solve the above technical problems are as follows: A synthesis method of xanthene dye, comprising the following steps: (1) In the presence of a base and a catalyst, an esterification reagent is used to carry out an esterification reaction on the hydroxyl group of sulfonyl fluorescein to obtain intermediate A; (2) In the presence of a base and a nickel catalyst, intermediate A and an amine compound are subjected to a C-N bond coupling reaction to obtain the target xanthene dye 2, and then the xanthene dye is applied in a color photoresist; Intermediate A is an aminosulfonate intermediate, a carbamate intermediate or a carboxylate intermediate; The chemical structural formulas of intermediate A and target xanthene dye 2 are as follows: ; The above synthesis route is as follows: ; The symbols in the formula represent the following meanings: R1 : Sulfamate, carbamate or tert-butyl carbonyl; R 2 : Independently represent a hydrogen atom, an alkyl substituent (such as a linear, branched or cyclic alkyl substituent with 1 to 20 carbon atoms), an aryl substituent (such as a group of a benzene ring, a naphthalene ring, a pyridine ring, an indene ring, an azulene ring, a heptalene ring, etc.); R 3 : Independently represent a hydrogen atom, an alkyl substituent (such as a linear, branched or cyclic alkyl substituent with 1 to 20 carbon atoms), an aryl substituent (such as a group of a benzene ring, a naphthalene ring, a pyridine ring, an indene ring, an azulene ring, a heptalene ring, etc.); R 4 : Independently represent a hydrogen atom, an alkyl substituent (such as a linear, branched or cyclic alkyl substituent with 1 to 20 carbon atoms), an aryl substituent (such as a group of a benzene ring, a naphthalene ring, a pyridine ring, an indene ring, an azulene ring, a heptalene ring, etc.); R 5 : Independently represent a hydrogen atom, an alkyl substituent (such as a linear, branched or cyclic alkyl substituent with 1 to 20 carbon atoms), an aryl substituent (such as a group of a benzene ring, a naphthalene ring, a pyridine ring, an indene ring, an azulene ring, a heptalene ring, etc.).

[0011] Preferably, in step (1), the base is an inorganic base or an organic base, more preferably any one or more of potassium carbonate, sodium carbonate, sodium hydroxide, potassium hydroxide, pyridine, triethylamine, 1,8-diazabicyclo[5.4.0]undec-7-ene, N,N-diisopropylethylamine, and even more preferably any one or more of pyridine, triethylamine, 1,8-diazabicyclo[5.4.0]undec-7-ene, N,N-diisopropylethylamine.

[0012] Preferably, in step (1), the amount of the base used is 1.0 to 2.5 times the equivalent amount, more preferably 1.1 to 1.5 times the equivalent amount.

[0013] Preferably, in step (1), the catalyst is any one or more of N,N-diisopropylethylamine, 4-dimethylaminopyridine DMAP, and triethylamine, and more preferably any one or two of 4-dimethylaminopyridine DMAP and triethylamine.

[0014] Preferably, in step (1), the amount of the catalyst used is 0.01 to 0.2 times the equivalent amount, more preferably 0.05 to 0.15 times the equivalent amount.

[0015] Preferably, in step (1), the esterification reagent is any one of pivalic anhydride, pivaloyl chloride, sulfamoyl chloride, dimethylaminosulfonyl chloride, N,N-diethylchloroformamide, and more preferably any one of pivalic anhydride, pivaloyl chloride, and sulfamoyl chloride.

[0016] Preferably, in step (1), the amount of the esterifying reagent is 1.0 to 2.5 equivalents, more preferably 1.05 to 1.2 equivalents.

[0017] Preferably, in step (1), the solvent used in the esterification reaction is any one or more of toluene, tetrahydrofuran, benzene, dichloromethane DCM, dichloroethane, chloroform, 1,4-dioxane, xylene, and more preferably any one or more of tetrahydrofuran, dichloromethane DCM, dichloroethane, chloroform, 1,4-dioxane.

[0018] Preferably, in step (1), the temperature of the esterification reaction does not exceed 30 °C, more preferably 0 to 25 °C.

[0019] Preferably, in step (1), the intermediate A is post-treated, and the post-treatment includes any one or more of extraction, flash chromatography, and crystallization.

[0020] Preferably, in step (2), the base is an inorganic base or an organic base, more preferably any one or more of potassium tert-butoxide, sodium tert-butoxide, lithium tert-butoxide, n-butyllithium, potassium carbonate, sodium carbonate, sodium hydroxide, potassium hydroxide, pyridine, triethylamine, 1,8-diazabicyclo[5.4.0]undec-7-ene, N,N-diisopropylethylamine, and more preferably any one or more of potassium tert-butoxide, sodium tert-butoxide, lithium tert-butoxide.

[0021] Preferably, in step (2), the amount of the base is 1.0 to 2.0 equivalents, more preferably 1.05 to 1.3 equivalents.

[0022] Preferably, in step (2), the nickel catalyst is any one or more of bis-(1,5-cyclooctadiene)nickel, nickel acetylacetonate, nickel chloride dimethoxyethane, nickel chloride, nickel bromide, and more preferably any one or more of bis-(1,5-cyclooctadiene)nickel, nickel acetylacetonate, nickel chloride dimethoxyethane.

[0023] Preferably, in step (2), the amount of the nickel catalyst is 0.01 to 0.2 equivalents, more preferably 0.02 to 0.1 equivalents.

[0024] Preferably, in step (2), the ligand of the nickel catalyst is any one or more of 1,2-bis(diphenylphosphino)ethane, 1,1'-bis(diphenylphosphino)ferrocene, 1,3-bis(2,4,6-trimethylphenyl)imidazolium chloride, 1,3-bis(2,6-diisopropylphenyl)imidazolium chloride, bipyridine, phenanthroline, and more preferably 1,3-bis(2,4,6-trimethylphenyl)imidazolium chloride or 1,3-bis(2,6-diisopropylphenyl)imidazolium chloride.

[0025] Preferably, in step (2), the amount of the ligand of the nickel catalyst is 0.02 to 0.4 times equivalent, more preferably 0.04 to 0.2 times equivalent.

[0026] Preferably, in step (2), the amine compound is at least one of the following structures: primary amine or secondary amine, and its general structural formula is NR 6 R 7 R 8 , where R 6 、R 7 are independently selected from hydrogen, C1-C6 alkyl, C3-C8 cycloalkyl, aryl or heteroaryl, and R 8 is hydrogen or C1-C6 alkyl; aromatic amine, and its general structural formula is Ar-NHR 9 , where Ar is phenyl, naphthyl or heteroaryl containing 1 to 3 heteroatoms (selected from N, O, S), and Ar is optionally substituted by C1-C4 alkyl, halogen, nitro or cyano, and R 9 is selected from hydrogen, C1-C6 alkyl, C3-C8 cycloalkyl, aryl or heteroaryl, and the amine compound is more preferably diethylamine or N-ethylaniline.

[0027] Preferably, in step (2), the amount of the amine compound is 2.0 to 5.0 times equivalent, more preferably 2.0 to 3.0 times equivalent.

[0028] Preferably, in step (2), the solvent used in the C-N bond coupling reaction is any one or more of toluene, tetrahydrofuran, benzene, dichloromethane DCM, dichloroethane, chloroform, 1,4-dioxane, xylene, and more preferably any one or more of toluene, tetrahydrofuran, 1,4-dioxane, xylene.

[0029] Preferably, in step (2), the temperature of the C-N bond coupling reaction is room temperature to 150 °C, more preferably 60 to 120 °C.

[0030] Preferably, in step (2), the xanthene dye 2 is post-treated, and the post-treatment includes column chromatography.

[0031] The present invention relates to a novel synthetic method for preparing xanthene dyes. First, the hydroxyl group on sulfonyl fluorescein is esterified to obtain intermediate A, and the intermediate A is an aminosulfonate intermediate, a carbamate intermediate or a carboxylate intermediate; then, under the condition of nickel catalysis, intermediate A and an amine compound carry out a C-N bond coupling reaction to construct the target xanthene dye.

[0032] Compared with the prior art, the beneficial effects of the present invention are: (1) The present invention avoids the strongly acidic and highly corrosive chlorinating reagents required by the traditional method, such as phosphorus oxychloride, phosphorus pentachloride, etc., reduces the corrosion of production equipment, has simple post-treatment, high safety, greatly reduces production costs, and improves the feasibility of large-scale production; (2) The nickel-catalyzed C-N coupling method adopted in the present invention reduces the reaction temperature, reduces the usage amount of amines, has less catalyst usage, simple post-treatment, and reduces production costs; (3) The present invention can be widely applied to the preparation of various types of amine-substituted xanthene dyes, and has excellent substrate applicability. Description of the Drawings

[0033] Figure 1 H-NMR spectrum of compound 2A prepared in Example 3 of the present invention; 1 H-NMR spectrum; Figure 2 C-NMR spectrum of compound 2A prepared in Example 3 of the present invention; 13 C-NMR spectrum; Figure 3 H-NMR spectrum of compound 2B prepared in Example 4 of the present invention; 1 H-NMR spectrum; Figure 4 C-NMR spectrum of compound 2B prepared in Example 4 of the present invention; 13 C-NMR spectrum. Detailed Embodiments

[0034] To better understand the content of the present invention, the following further illustrates with specific examples and drawings. It should be understood that these examples are only used to further illustrate the present invention, rather than to limit the scope of the present invention. In addition, it should be understood that after reading the content described in the present invention, those skilled in the art make some non-essential changes or adjustments to the present invention, which still fall within the protection scope of the present invention.

[0035] The present invention uses LC-MS to determine the structure of the compound and obtains the compound purity by the integration area in LC-MS.

[0036] Example 1 (Synthesis of Intermediate A1-1) Method 1: Take a clean 500 mL three-necked flask and place a stir bar of appropriate size; add sulfonyl fluorescein (37.05 g, 100.9 mmol, 1.0 eq.), DMAP (12 mg), and then add pyridine (200 mL) for dissolution. Place the above system in an ice-water bath and stir for 15 minutes; after the temperature of the above system stabilizes at 0 °C, dropwise add pivaloyl chloride (25.55 g, 211.9 mmol, 2.1 eq.). After the addition of pivaloyl chloride is complete, transfer the above reaction system to room temperature and react overnight; the next day, add deionized water to quench the reaction, and then add 100 mL of dichloromethane (DCM) for extraction multiple times; add anhydrous sodium sulfate to dry the organic phase, filter by suction, and remove the solvent by rotary evaporation under reduced pressure to obtain 61.53 g of crude product intermediate A1-1 with a yield of 88%. Without purification, directly proceed to the next step of the reaction.

[0037] Method 2: Take a clean 500 mL three-necked flask and place a stir bar of appropriate size; suspend sulfonyl fluorescein (18.47 g, 50.1 mmol, 1.0 eq.) in anhydrous toluene (250 mL), then add pivaloyl chloride (12.4 g, 102.8 mmol, 2.1 eq.), triethylamine (15.3 mL, 110.2 mmol, 2.2 eq.), and DMAP (5 mg); at room temperature, stir the reaction mixture under a nitrogen atmosphere for 24 hours; filter out the solid and wash it with toluene; remove the solvent under reduced pressure, and purify the residue by flash chromatography (petroleum ether:ethyl acetate = 5:1) or crystallization twice to obtain 21.78 g of purified product intermediate A1-1 with a yield of 81%, and proceed to the next step of the reaction.

[0038] Method 3: Take a clean 500 mL three-necked flask and place a stir bar of appropriate size; suspend sulfonyl fluorescein (18.47 g, 50.1 mmol, 1.0 eq.) in anhydrous toluene (250 mL), then add pivalic anhydride (16.7 g, 102.8 mmol, 2.1 eq.), triethylamine (15.3 mL, 110.2 mmol, 2.2 eq.), and DMAP (5 mg); at room temperature, stir the reaction mixture under a nitrogen atmosphere for 24 hours; filter out the solid and wash it with toluene; remove the solvent under reduced pressure, and purify the residue by flash chromatography (petroleum ether:ethyl acetate = 5:1) or crystallization twice to obtain 20.4 g of purified product intermediate A1-1 with a yield of 76%, and proceed to the next step of the reaction.

[0039] The chemical structural formula of the intermediate A1-1 is as follows: 。

[0040] Example 2 (Synthesis of Intermediate A1-2) Take a clean 500 mL three-necked flask and place a stir bar of appropriate size; dissolve sulfonyl fluorescein (18.47 g, 50.1 mmol, 1.0 eq.) and DMAP (12 mg) in 200 mL of anhydrous pyridine, and stir the above system in an ice-water bath for 15 minutes; after the temperature of the above system stabilizes at 0 °C, slowly add chlorosulfonamide (11.88 g, 102.8 mmol, 2.1 eq.) dropwise. After the addition of chlorosulfonamide is complete, transfer the above reaction system to room temperature and react overnight; the next day, add deionized water to quench the reaction, and then add 100 mL of dichloromethane (DCM) for extraction multiple times; add anhydrous sodium sulfate to dry the organic phase, filter by suction, and remove the solvent by rotary evaporation to obtain 20.31 g of crude product Intermediate A1-2 with a yield of 77%. No purification is required, and it can be directly used for the next reaction.

[0041] The chemical structural formula of the Intermediate A1-2 is as follows: 。

[0042] Example 3 (Synthesis of Compound 2A) Add bis-(1,5-cyclooctadiene)nickel (350 mg, 1.25 mmol), 1,3-bis(2,6-diisopropylphenyl)imidazolium chloride (1.05 g, 2.5 mmol), sodium tert-butoxide (6.73 g, 70 mmol), A1-1 prepared by Method 2 of Example 1 (26.8 g, 50 mmol), N-ethylaniline (14.54 g, 120 mmol) and toluene (250 mL), and then place it in a nitrogen atmosphere; stir the reaction mixture at 70 °C for 3 hours; after cooling to room temperature, purify the crude mixture by flash column chromatography on silica gel (eluent: methanol / dichloromethane = 1:10) to obtain Compound 2A as a purple-red solid powder (26.44 g, 92%).

[0043] The chemical structural formula of the Compound 2A is as follows: 。

[0044] The 1 1H-NMR spectrum and 13 13C-NMR spectrum of Compound 2A are shown in Figure 1 and Figure 2 。

[0045] Example 4 (Synthesis of Compound 2B) The catalyst bis-(1,5-cyclooctadiene)nickel (350 mg, 1.25 mmol), 1,3-bis(2,6-diisopropylphenyl)imidazolium chloride (1.05 g, 2.5 mmol), sodium tert-butoxide (6.73 g, 70 mmol), A1-1 prepared by the method two of Example 1 (26.8 g, 50 mmol), diethylamine (8.78 g, 120 mmol) and toluene (250 mL) were then placed in a nitrogen atmosphere; the reaction mixture was stirred at 70 °C for 3 hours; after cooling to room temperature, the crude mixture was purified by flash column chromatography on silica gel (eluent: methanol / dichloromethane = 1:10) to obtain compound 2B as a purple-red solid powder (21.51 g, 90%).

[0046] The chemical structural formula of the said compound 2B is as follows: 。

[0047] The 1 1H-NMR spectrum and 13 13C-NMR spectrum of the said compound 2B are shown in Figure 3 and Figure 4 respectively.

[0048] Comparative Example 1 (Synthesis of Compound 2A) (1) Synthesis of Chlorinated Intermediate A2 A clean 250 mL single-necked flask was taken and a stir bar of appropriate size was placed; sulfonyl fluorescein (18.47 g, 50.1 mmol, 1.0 eq.) and phosphorus oxychloride (76.67 g, 0.5 mol, 1.0 eq.) were added respectively; the mixture was heated to 105 °C and stirred at 105 °C for 18 hours; after the reaction was completed, it was cooled to room temperature; then, the obtained reaction solution was added dropwise to a 2 L three-necked flask containing 1 L of water in an ice-water bath at a temperature below 20 °C; after the addition was completed, it was stirred at 20 °C for 1 hour; the obtained suspension was filtered, sprayed and washed once with 200 mL of water, and then sprayed and washed twice with 200 mL of acetonitrile; the washed crystals were dried in a blast dryer at 50 °C for 12 hours to obtain 6.7 g of chlorinated intermediate A2 with a yield of 33%, and the next reaction was carried out.

[0049] The chemical structural formula of the said chlorinated intermediate A2 is as follows: 。

[0050] (2) Synthesis of Compound 2A Take a clean 250 mL single-necked flask and place a stir bar of appropriate size. Under light-protected conditions, add compound A2 (4.06 g, 10 mmol, 1.0 eq.), N-ethylaniline (12.12 g, 100 mmol, 10 eq.) and N-methylpyrrolidone (50 mL) respectively. Subsequently, stir the reaction mixture at 125 °C overnight. After cooling to room temperature, purify the crude mixture by flash column chromatography on silica gel (eluent: methanol / dichloromethane = 1:20) to obtain compound 2A as a purple-red solid powder (1.7 g, 29.6%).

[0051] The chemical structural formula of the said compound 2A is as follows: 。

[0052] The synthesis method of the xanthene dye of the present invention avoids the need to first chlorinate sulfonyl fluorescein using strong acidic and corrosive chlorinating reagents such as phosphorus oxychloride, phosphorus pentachloride or thionyl chloride in the traditional synthesis method. It not only reduces the generation of a large amount of strong acidic gases, but also reduces the corrosion of production equipment. Moreover, the nickel-catalyzed C-N coupling reaction has mild conditions, greatly reducing the reaction temperature and energy consumption, making this synthesis method more suitable for large-scale industrial production.

[0053] The above description is not a limitation of the present invention, nor is the present invention limited to the above examples. Changes, modifications, additions or substitutions made by those of ordinary skill in the art within the scope of the essence of the present invention shall also fall within the protection scope of the present invention.

Claims

1. A method for synthesizing xanthene dyes, characterized in that, It includes the following steps: (1) In the presence of a base and a catalyst, the hydroxyl group on sulfonyl fluorescein is esterified with an esterifying reagent to obtain intermediate A; (2) In the presence of a base and a nickel catalyst, intermediate A undergoes a C-N bond coupling reaction with an amine compound to obtain the target xanthene dye 2; Intermediate A is an aminosulfonate intermediate, a carbamate intermediate or a carboxylate intermediate; The chemical structural formulas of intermediate A and target xanthene dye 2 are as follows: ； The symbols in the formula represent the following meanings: R 1 : sulfamate, carbamate or tert-butyl carbonyl; R 2 : each independently represents a hydrogen atom, an alkyl substituent, or an aryl substituent; R 3 : independently represent a hydrogen atom, an alkyl substituent, or an aryl substituent, respectively; R 4 : each independently represents a hydrogen atom, an alkyl substituent, an aryl substituent; R 5 : independently represent a hydrogen atom, an alkyl substituent, and an aryl substituent, respectively.

2. The synthesis method of a xanthene dye according to claim 1, characterized in that In step (1), the base is an inorganic base or an organic base.

3. The synthesis method of a xanthene dye as described in claim 1, characterized in that, In step (1), the catalyst is any one or more of N,N-diisopropylethylamine, 4-dimethylaminopyridine, and triethylamine.

4. The synthesis method of a xanthene dye as claimed in claim 1, characterized in that, In step (1), the esterifying reagent is any one of pivalic anhydride, pivaloyl chloride, sulfamoyl chloride, dimethylaminosulfonyl chloride, and N,N-diethylchloroformamide.

5. The synthesis method of a xanthene dye according to claim 1, characterized in that, In step (1), the dosage of the base is 1.0 - 2.5 fold equivalents; the dosage of the catalyst is 0.01 - 0.2 fold equivalents; the dosage of the esterifying reagent is 1.0 - 2.5 fold equivalents.

6. The synthesis method of a xanthene dye according to claim 1, characterized in that, In step (1), the temperature of the esterification reaction does not exceed 30 °C.

7. The synthesis method of a xanthene dye according to claim 1, characterized in that, In step (2), the base is an inorganic base or an organic base.

8. The synthesis method of a xanthene dye according to claim 1, characterized in that, In step (2), the nickel catalyst is any one or more of bis-(1,5-cyclooctadiene)nickel, nickel acetylacetonate, nickel chloride dimethoxyethane, nickel chloride, and nickel bromide; the ligand of the nickel catalyst is any one or more of 1,2-bis(diphenylphosphino)ethane, 1,1'-bis(diphenylphosphino)ferrocene, 1,3-bis(2,4,6-trimethylphenyl)chloroimidazolium, 1,3-bis(2,6-diisopropylphenyl)chloroimidazolium, bipyridine, and phenanthroline.

9. The synthesis method of a xanthene dye according to claim 1, characterized in that, In step (2), the dosage of the base is 1.0 - 2.0 fold equivalents; the dosage of the nickel catalyst is 0.01 - 0.2 fold equivalents; the dosage of the ligand of the nickel catalyst is 0.02 - 0.4 fold equivalents; the dosage of the amine compound is 2.0 - 5.0 fold equivalents.

10. The synthesis method of a xanthene dye according to claim 1, characterized in that, In step (2), the temperature of the C-N bond coupling reaction is from room temperature to 150 °C.

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