Synthesis method and application of boric acid ester tricyclic hemicyanine

Abstract

The invention provides a novel borate tricyclic hemicyanine dye and a synthesis method thereof, and the dye has excellent fluorescence performance and is suitable for biological detection and medical imaging. Two synthesis routes are provided, 5-formylfuran-2-boric acid is used as a raw material, and the target dye is efficiently synthesized through different chemical reaction routes. According to the route I, hemicyanine and indole quaternary ammonium salt are condensed to form a hemicyanine intermediate, and the hemicyanine intermediate reacts with o-aminophenol or a derivative thereof; the route II is firstly condensed with aniline or a derivative thereof to form an imine intermediate, and then a final product is synthesized through a substitution reaction. The synthesis steps are simple, conditions are mild, and large-scale production is facilitated. The synthesized dye has good water solubility and biocompatibility, is adjustable in fluorescence characteristic, and is suitable for various biomedical applications. The embodiment and attached drawings show the synthesis process, the fluorescence property and the application thereof in cell imaging in detail, and show the important value in scientific research and practical application.

Description

Technical Field

[0001] The invention relates to a synthesis technology of fluorescent dyes, in particular to a borate tricyclic semicyanine dye with excellent fluorescent properties and a synthesis method thereof. The dye has important applications in the field of biological detection, especially in the detection of nitroreductase in cells. Background Art

[0002] Fluorescence imaging is a non-invasive imaging technology with the advantages of being non-invasive, real-time, visual, and having high spatiotemporal resolution, which can achieve rapid diagnosis of diseases. The fluorescent mother nucleus is the "core skeleton" of a fluorescent probe. The characteristics of the fluorescent mother nucleus directly determine the optical properties of the probe and its application potential in disease diagnosis and treatment. Currently, the common fluorescent mother nuclei include: cyanine dyes, rhodamine, coumarin, DAD, and BODIPY. Although there are many fluorescent probes with this as the core, most of them still have problems such as difficult synthesis, poor stability, short fluorescence wavelength, low fluorescence brightness, few chemical modification sites, and difficult fluorescence regulation. Therefore, it is of great significance to understand the relationship between the structure and performance of the fluorescent mother nucleus and develop new multifunctional fluorescent mother nuclei in medical diagnosis and treatment. Summary of the invention

[0003] The purpose of the present invention is to provide a novel boronate tricyclic hemicyanine dye, which is easy to synthesize, has excellent optical properties and easy structural controllability, and is suitable for the detection of nitroreductase in cells. The present invention also provides a method for synthesizing the dye, including two synthetic routes, and shows through specific examples that some of the dyes, such as dyes with a nitro group on R1, can also be used in the detection of nitroreductase.

[0004] The structural formula of the borate tricyclic semicyanine is as follows:

[0005] in

[0006]

[0007] The structural formula corresponding to the dotted box is

[0008] etc. (where the carbon corresponding to the circle is one carbon of the double bond).

[0009] R in the structural formula 1 are H, alkyl or substituted alkyl groups of 1 to 20 carbon atoms (such as aromatic ring substitution or aromatic ring substitution with substituents, etc.), sulfonic acid group, phosphoric acid group, carboxyl group and carboxylic acid derivative group, aromatic ring and aromatic ring with substituents, the substituents on the above aromatic rings are nitro, carboxyl, amine, etc., which may be monosubstituted or polysubstituted; R in the structural formula2 , R 3 R is H at different positions on the benzene ring, alkyl or halogen-substituted alkyl (the number of carbon atoms in the alkyl group is 1-20, etc.), olefin, alkynyl, aromatic group, hydroxyl, amine, halogen, nitro, benzyloxy, alkoxy, benzene ring or various water-soluble groups (e.g., SO3M); 4 It is H, alkyl (alkyl has 1-20 carbon atoms), olefin, alkynyl, aromatic, hydroxyl, halogen, nitro, benzyloxy, alkoxy, benzene ring or various water-soluble groups (e.g. SO3M). The alkyl mentioned above is selected from alkyl with 1-20 carbon atoms.

[0010] The method for synthesizing a borate tricyclic semicyanine dye of the present invention uses 5-formaldehyde furan-2-boric acid as a starting material, first condenses with an indole quaternary ammonium salt to prepare a semicyanine, then reacts with o-aminophenol (and its derivatives), and finally synthesizes a borate tricyclic semicyanine product. Alternatively, 5-formaldehyde furan-2-boric acid is used as a starting material, first condenses with an aniline (and its derivatives) to prepare an imine compound, then reacts with o-aminophenol (and its derivatives), and finally adds a base and an indole quaternary ammonium salt for substitution reaction, and finally synthesizes a borate tricyclic semicyanine product. Specifically, it includes the following:

[0011] Route I:

[0012] Synthesis route:

[0013]

[0014] Step 1, 5-formaldehyde furan-2-boric acid A and a heterocyclic compound B (0.2 to 1 times the amount of the feed) are dissolved in a solvent (either a polar solvent or a non-polar solvent), 0.01 to 5 times of a base is used as a catalyst, and the above multiples are based on 5-formaldehyde furan-2-boric acid A, and react at 60 to 140° C. for 1 to 12 hours to obtain a crude product C, and the solvent is removed to obtain a compound C;

[0015] Step 2, compound C and o-aminophenol or its derivative D (0.5 to 3 times the amount of the feed) are mixed in a solvent (either a polar solvent or a non-polar solvent), the above multiples being based on compound C, reacting at 0 to 70° C. for 5 to 60 minutes, removing the solvent, and obtaining a pure compound E, i.e., a borate tricyclic semicyanine dye, through column chromatography.

[0016] In step 1, the solvent required for the reaction is ethanol, methanol, acetonitrile, dichloromethane, acetone, etc., and the base required is piperidine, pyridine, triethylamine, etc.;

[0017] The heterocyclic ring B is selected from: Or other aromatic substituted heterocyclic structure compounds having active methyl or active methylene groups; aromatic substituted heterocyclic structures having active methylene groups are selected from the following (wherein the carbon within the dotted circle is used to form a double bond):

[0018]

[0019] The o-aminophenol (or its derivative) D is selected from: Or a compound in which the hydroxyl group and the amino group are ortho positions; other compound structures in which the hydroxyl group and the amino group are ortho positions are selected from the following:

[0020]

[0021] In step 2, Y in the structural formula - Anions, mainly halogen ions, PF6 - 、ClO4 - , TsO - wait;

[0022] R in the structural formula 1 are H, alkyl or substituted alkyl groups of 1 to 20 carbon atoms (such as aromatic ring substitution or aromatic ring substitution with substituents, etc.), sulfonic acid group, phosphoric acid group, carboxyl group and carboxylic acid derivative group, aromatic ring and aromatic ring with substituents, the substituents on the above aromatic rings are nitro, carboxyl, amine, etc., which may be monosubstituted or polysubstituted; R in the structural formula 2 , R 3 It is H at different positions on the benzene ring, alkyl or halogen-substituted alkyl (the number of carbon atoms in the alkyl group is 1-20, etc.), olefin, alkynyl, aromatic group, hydroxyl, amine, halogen, nitro, benzyloxy, alkoxy, benzene ring or various water-soluble groups (e.g. SO3M). It can be monosubstituted or polysubstituted; R 4 It is H, alkyl (alkyl has 1-20 carbon atoms), olefin, alkynyl, aromatic, hydroxyl, halogen, nitro, benzyloxy, alkoxy, benzene ring or various water-soluble groups (e.g. SO3M). The alkyl mentioned above is selected from alkyl with 1-20 carbon atoms.

[0023] Route 2:

[0024] Synthesis route:

[0025]

[0026] Step 1, 5-formaldehyde furan-2-boric acid A and aniline F (0.2 to 1 times of the feed amount) are dissolved in a solvent, the above multiple is based on 5-formaldehyde furan-2-boric acid A, react at 0 to 70° C. for 1 to 12 hours to obtain an intermediate product G, continue to add o-aminophenol or its derivative D (0.5 to 3 times of the feed amount) in a solvent, the above multiple is based on compound A, react at 0 to 70° C. for 1 to 12 hours, and evaporate the solvent under reduced pressure to obtain a crude product H.

[0027] Step 2, the crude product H and the heterocyclic compound B (0.5 to 3 times the amount of the feed) are mixed in an alkaline solution, the above multiples are based on the compound H, react at 40 to 120°C for 1 to 12 hours, remove the solvent, and obtain a pure compound E, i.e., a borate tricyclic semicyanine dye, through column chromatography.

[0028] In step 1, the solvent required for the reaction is ethanol, methanol, acetonitrile, dichloromethane, acetone, etc.

[0029] o-Aminophenol or its derivative D is consistent with method I; further in step 2, the solvent required for the reaction is ethanol, methanol, acetonitrile, dichloromethane, acetone, etc., and the base required is piperidine, pyridine, triethylamine, etc.; heterocycle B is consistent with method I.

[0030] The raw materials involved in the method of the present invention are easy to prepare, the synthesis route is short, the reaction conditions are mild, and the method is suitable for large-scale production. The semi-cyanine dye prepared by the present invention has good water solubility, stability and biocompatibility.

[0031] The borate tricyclic semi-cyanine dye and its synthesis method involved in the present invention have fluorescence and can be further used for but not limited to infrared fluorescence imaging, photoacoustic imaging, photodynamic therapy, sonodynamic therapy, photothermal therapy, and further application in nitroreductase detection.

[0032] Beneficial effects:

[0033] Compared with the prior art, the borate tricyclic hemicyanine dye provided by the present invention has the following advantages:

[0034] (1) The synthesis process is simple, the reaction conditions are mild, and it is easy to produce on a large scale.

[0035] (2) The dye has excellent water solubility, stability and biocompatibility.

[0036] (3) Excellent fluorescence performance and adjustable fluorescence wavelength, suitable for a variety of biological detection technologies. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is the ultraviolet a and fluorescence b spectra of the probe TBEH-NO2 after reacting with NTR;

[0038] Figure 2 These are confocal microscopy photos of HeLa cells under the effect of the probe TBEH-NO2, where a and c are bright field photos of b and d (b is cells co-incubated with the probe; d is cells co-incubated with the probe and NTR);

[0039] Figure 3 The final product compound E of Example 1 1 H NMR spectrum;

[0040] Figure 4 The final product compound E of Example 1 13 C NMR spectrum;

[0041] Figure 5 is the HRMS spectrum of the final product compound E of Example 1;

[0042] Figure 6 The final product compound E of Example 2 1 H NMR spectrum;

[0043] Figure 7 The final product compound E of Example 2 13 C NMR spectrum;

[0044] Figure 8 is the HRMS spectrum of the final product compound E of Example 2;

[0045] Fig. 9 The final product compound E of Example 3 1 H NMR spectrum;

[0046] Fig.10 The final product compound E of Example 3 13 C NMR spectrum;

[0047] Fig.11 is the HRMS spectrum of the final product compound E of Example 3;

[0048] Fig.12 The final product compound E of Example 4 1 H NMR spectrum;

[0049] Fig.13 The final product compound E of Example 4 13 C NMR spectrum;

[0050] Fig.14 is the HRMS spectrum of the final product compound E of Example 4;

[0051] Fig.15 The final product compound E of Example 5 1 H NMR spectrum;

[0052] Fig.16 The final product compound E of Example 5 13 C NMR spectrum;

[0053] Fig.17 is the HRMS spectrum of the final product compound E of Example 5;

[0054] Fig.18 The final product compound E of Example 6 1 H NMR spectrum;

[0055] Fig.19 The final product compound E of Example 6 13 C NMR spectrum;

[0056] Fig. 20 is the HRMS spectrum of the final product compound E of Example 6;

[0057] Fig.21 This is the UV-visible absorption spectrum of the final product E of Example 1-6 in MeOH;

[0058] Fig. 22 This is the fluorescence emission spectrum of the final product E of Example 1-6 in MeOH. DETAILED DESCRIPTION

[0059] The following specific embodiments will help to understand the present invention, but will not limit the contents of the present invention.

[0060] Example 1

[0061] This embodiment is a route 1 for synthesizing borate tricyclic semicyanine dyes. The synthesis method is:

[0062]

[0063] 5-Formaldehydefuran-2-boronic acid A (1.33 g) and heterocycle B (5 g) were mixed in methanol (20 mL), piperidine (20 μL) was added, and the mixture was refluxed for 6 hours. The mixture was washed with dichloromethane three times and dried to obtain semicyanine C.

[0064] 1H NMR (600MHz, DMSO-d6) δ8.74(s,2H),8.48–8.40(m,2H),8.31(d,J=9.0Hz,1H),8.22(d,J=9.0Hz,1H),8.13(d,J=9.0Hz ,1H),7.81(t,J=7.5Hz,1H),7.73(t,J=7.5Hz,1H),7.50–7.42(m,2H),7.32(d,J=3.5Hz,1H),4.22(s,3H),1.99(s,6H). 13 C NMR(101MHz,DMSO-d6)δ182.01,154.44,139.95,138.39,137.14,133.60,131.39,130.51,128.91,12 7.64,127.15,125.01,123.70,123.49,113.71,110.27,53.92,35.15,25.62.Mp.179–182℃.HRMS(ESI + ):cacld.for C 21 H 21 BNO3 + [M] + 346.1609 found 346.1605.

[0065] Semicyanine C (100 mg) and o-aminophenol D (38.69 mg) were mixed in methanol (7.5 mL), refluxed for 30 minutes, and purified by silica gel column chromatography to obtain pure compound E with a yield of 84%.

[0066] 1 H NMR (400MHz, Chloroform-d) δ (ppm) 12.49 (s, 1H), 8.01 (d, J = 8.5Hz, 1H), 7.82 (d, J = 8.5Hz, 1H), 7.77 (d, J = 8.5Hz, 1H), 7.48 (t, J = 7.6Hz ,1H),7.29(t,J=7.6Hz,1H),7.17–7.02(m,3H),6.71–6.52(m,4H),6.22(d,J=12.4Hz,1H),5.86–5.68(m,1H),3.40(s,6H),1.94(s,6H). 13C NMR(101MHz,Chloroform-d)δ(ppm)156.29,154.26,150.69,147.07,134.98,134.89,134.76,133.53,133.26,132.21,131.79,1 30.32,129.58,127.71,126.69,124.26,123.42,117.34,115.37,99.10,98.89,53.83,53.11,34.86,31.77.Mp.>320℃.HRMS(ESI + ):cacld.for C 28 H 27 BN2O3[M-CH3O] + 419.1925found 419.1920.LRMS(ESI + ):cacld.for C 28 H 27 BN2O3[M-CH3O] + 419.2found 419.2.

[0067] Example 2

[0068] This embodiment is a route 1 for synthesizing borate tricyclic semicyanine dyes. The synthesis method is:

[0069]

[0070] Semicyanine C (100 mg) and o-aminophenol derivative D (44.12 mg) were mixed in methanol (7.5 mL), refluxed for 30 minutes, and purified by silica gel column chromatography to obtain pure compound E with a yield of 73%.

[0071] 1 H NMR (600MHz, DMSO-d6) δ (ppm) 11.80 (s, 1H), 8.03 (d, J = 8.4Hz, 1H), 7.88 (d, J = 8.4Hz, 1H) ,7.85(d,J=8.4Hz,1H),7.49((t,J=7.2Hz,1H),7.39(d,J=8.4Hz,1H),7.27((t,J=7.2Hz ,1H),6.98(d,J=8.4Hz,1H),6.64–6.53(m,2H),6.41–6.38(m,1H),6.38–6.32(m,1H),6. 16(d,J=8.4Hz,1H),5.93(d,J=12.6Hz,1H),3.37–3.34(m,5H),1.87(s,3H),1.86(s,3H). 13C NMR(101MHz,DMSO-d6)δ(ppm)161.45,149.60,145.45,142.96,142.47,140.64,130.19,129.95,129.05,128.86,127.92,127.33,123.3 6,121.85,119.63,114.24,113.05,110.44,104.97,94.28,79.76,79.43,79.10,55.30,48.06,46.12,29.98,26.98.Mp.>320℃.HRMS(ESI - ):cacld.for C 28 H 28 BN3O3[MH] - 464.2145 found 464.2154.

[0072] Example 3

[0073] This embodiment is a route 1 for synthesizing borate tricyclic semicyanine dyes. The synthesis method is:

[0074]

[0075] Semicyanine C (100 mg) and o-aminophenol derivative D (56.16 mg) were mixed in methanol (7.5 mL), refluxed for 30 minutes, and purified by silica gel column chromatography to obtain pure compound E with a yield of 73%.

[0076] 1 H NMR (400MHz, DMSO-d6) δ (ppm) 11.92 (s, 1H), 8.10 (d, J = 8.5Hz, 1H), 7.96–7.88 (m, 2H), 7.58–7.47 (m, 2H), 7.34 (t, J = 7.7Hz, 1H) ,7.21(d,J=8.5Hz,1H),7.18–7.01(m,3H),6.98–6.81(m,1H),6.27–5.93(m,2H),3.27–3.12(m,3H),3.01(s,2H),1.88(s,6H). 13CNMR(150MHz,DMSO-d6)δ(ppm)165.97,164.64,151.79,151.49,149.92,146.12,142.07,141.91,132.25,130.54,130.41,130.26,130.13,129 .45,128.59,127.61,123.50,122.10,119.48,115.74,115.50,111.54, 110.95,94.84,49.07,47.76,30.44,27.14,27.02.Mp.>320℃.HRMS(ESI - ):cacld.for C 29 H 26 BF3N2O3[MH] - 517.1921 found 517.1923.

[0077] Example 4

[0078] This embodiment is a method for synthesizing borate tricyclic semicyanine dyes by route 2:

[0079]

[0080] 5-Formaldehyde furan-2-boric acid A (522 mg) and aniline F (650 mg) were mixed in methanol (15 mL), stirred at room temperature for 1 hour, and o-aminophenol D (407 mg) was added, refluxed for 2 hours, and the organic solvent was evaporated under reduced pressure. The crude product (100 mg) and heterocycle B (138.6 mg) were mixed in pyridine (4 ml), heated and stirred at 70° C. for 30 minutes, and purified by silica gel column chromatography to obtain pure compound E with a yield of 47%.

[0081] 1 H NMR(600MHz,Chloroform-d)δ(ppm)12.93(s,1H),7.46(d,J=8.4Hz,1H),7.37–7.33(m,1H),7.12–7.06(m,2H),6.71(d,J=8.4Hz,1H),6.66 –6.54(m,2H),6.54–6.46(m,1H),6.41(d,J=12.0Hz,1H),6.20(d,J=12.0Hz,1H),5.82–5.61(m,1H),3.36(s,2H),3.26(s,3H),1.64(s,6H). 13C NMR(150MHz,Chloroform-d)δ(ppm)159.73,150.23,148.90,147.42,145.64,139.71,128.40,127.70,125.91,125.68,123 .88,122.48,122.27,120.34,119.98,119.33,118.61,114.25,106.33,95.60,46.01,29.84,27.98.Mp.198–202℃.HRMS(ESI - ):cacld.for C 25 H 24 BF3N2O3[MH] - 467.1759 found 467.1762.

[0082] Example 5

[0083] This embodiment is a method for synthesizing borate tricyclic semicyanine dyes by route 2:

[0084]

[0085] 5-Formaldehyde furan-2-boric acid A (522 mg) and aniline F (650 mg) were mixed in methanol (15 mL), stirred at room temperature for 1 hour, o-aminophenol D (407 mg) was added, refluxed for 2 hours, and the organic solvent was evaporated under reduced pressure. The crude product (100 mg) and heterocycle B (124.53 mg) were mixed in pyridine (4 ml), heated and stirred at 70° C. for 30 minutes, and purified by silica gel column chromatography to obtain pure compound E with a yield of 47%.

[0086] 1 H NMR(600MHz,Chloroform-d)δ(ppm)12.47(d,J=121.3Hz,1H),7.10(d,J=8.4Hz,1H ),7.06(t,J=7.8Hz,1H),6.84–6.80(m,1H),6.79–6.75(m,1H),6.65(d,J=8.4Hz,1 H),6.63–6.52(m,3H),6.49(d,J=12.6Hz,1H),6.14(d,J=12.6Hz,1H),5.78–5.57( m,1H),3.82(s,3H),3.35(s,2H),3.26(d,J=7.6Hz,3H),1.68(s,3H),1.60(s,3H). 13C NMR(150MHz,Chloroform-d)δ(ppm)161.74,155.20,150.24,148.27,144.72,141.01,138.54,128.97,126.75,126.23,120. 03,119.75,119.05,112.38,111.98,109.49,107.14,94.23,55.98,46.80,45.73,29.95,29.70,27.92.Mp.>320℃.HRMS(ESI - ):cacld.for C 25 H 27 BN2O4[MH] - 429.1989 found 429.1994.

[0087] Example 6

[0088] This embodiment is a near-infrared fluorescent probe TBEH-NO2 for nitroreductase detection, and the synthesis method is:

[0089]

[0090] Hemicyanine C (200 mg) and 2-aminophenol derivative D (154.55 mg) were mixed in methanol (5 mL), and the mixture was heated to reflux and stirred for 30 min. Pure compound TBEH-NO2 was obtained by silica gel column chromatography with a yield of 47%.

[0091] 11H NMR (400 MHz, Chloroform-d) δ (ppm) 8.21 (d, J = 8.8 Hz, 2H), 8.02 (d, J = 8.8 Hz, 1H), 7.89–7.81 (m, 2H), 7.52 (t, J = 7.2 Hz, 1H), 7.46 (d, J = 8.8 Hz, 2H), 7.36 (t, J = 7.2 Hz, 1H), 7.21 (d, J = 8.8 Hz, 1H), 7.18–7.12 (m, 1H), 7.10–7.03 (m, 1H), 6.92–6.82 (m, 2H), 6.79 (d, J = 8.8 Hz, 1H), 6.74–6.65 (m, 1H), 6.53–6.42 (m, 1H), 5.95 (t, J = 8.4 Hz, 1H), 5.45–5.34 (m, 1H), 5.24–5.08 (m, 1H), 3.52 (s, 3H), 3.35 (s, 2H), 2.62 (q, J = 7.2 Hz, 6H, triethylamine), 1.96–1.89 (m, 6H), 1.08 (t, J = 7.2 Hz, 9H, triethylamine). 13 13C NMR (101 MHz, Chloroform-d) δ (ppm) 167.93, 167.82, 151.63, 149.81, 147.57, 144.53, 142.51, 141.07, 132.85, 131.31, 130.80, 130.01, 127.26, 127.08, 126.89, 124.45, 123.62, 121.82, 120.93, 120.69, 118.95, 116.54, 109.70, 107.54, 106.96, 96.61, 96.51, 49.38, 48.01, 46.19 (triethylamine), 30.58, 29.72, 27.44, 27.35, 27.31, 27.29, 11.17 (triethylamine). Mp. 186–191 °C. HRMS (ESI - ): cacld. for C 35 H 32 BN3O5 [M-H] - 584.2357 found 584.2365. LRMS (ESI + ): cacld. for C 35 H 32 BN3O5 [M–CH3O] + 584.2 found 584.2.

[0092] Example 7

[0093] The nitroreductase fluorescent probe TBEH-NO2 prepared in Example 6 was dissolved in PBS, and its absorption spectrum was measured using a UV-visible spectrophotometer. Figure 1 As shown in a. The maximum ultraviolet absorption of the probe TBEH-NO2 itself is 681nm. When nitroreductase (NTR) is added to the probe solution, the absorption peak at 681nm decreases.

[0094] The fluorescence spectra of the compound in PBS and PBS with NTR added were tested using a fluorescence spectrometer. Figure 1 As shown in b, the probe TBEH-NO2 produces almost no fluorescence in the range of 670-850nm, but when the probe interacts with NTR, it produces strong fluorescence at 698nm.

[0095] The cell confocal imaging experiment of the probe TBEH-NO2 was carried out using a confocal microscope. Figure 2 As shown in the figure, living cells loaded with probes only did not produce fluorescence under normoxic conditions. However, when living cells loaded with probes were co-incubated with NTR under hypoxic conditions,

[0096] It shows obvious fluorescence enhancement. It can be seen that the probe has a better response imaging effect.

[0097] The UV-visible light absorption and fluorescence emission of Examples 1-6 show Fig.21 and Fig. 22 , is fluorescent, and has potential applications in fluorescence imaging, photoacoustic imaging, photodynamic therapy, sonodynamic therapy, photothermal therapy, and other fields.

Claims

1. A borate tricyclic hemicyanine dye, characterized in that: The structural formula is as follows: in The structural formula corresponding to the dotted box is The carbon corresponding to the dotted circle is one carbon of the double bond; R in the structural formula 1 are H, alkyl or substituted alkyl groups of 1 to 20 carbon atoms (such as aromatic ring substitution or aromatic ring substitution with substituents), sulfonic acid, phosphoric acid, carboxyl and carboxylic acid derivative groups, aromatic rings and aromatic rings with substituents. The substituents on the above aromatic rings are nitro, carboxyl, amine, etc., which may be monosubstituted or polysubstituted. R in the structural formula 2 , R 3 R is H at different positions on the benzene ring, alkyl or halogen-substituted alkyl (the number of carbon atoms in the alkyl group is 1-20, etc.), olefin, alkynyl, aromatic group, hydroxyl, amine, halogen, nitro, benzyloxy, alkoxy, benzene ring or various water-soluble groups (e.g., SO3M); 4 It is H, alkyl (the number of carbon atoms in the alkyl group is 1-20, etc.), olefin, alkynyl, aromatic group, hydroxyl, halogen, nitro, benzyloxy, alkoxy, benzene ring or various water-soluble groups (e.g. SO3M).

2. The method for preparing the borate tricyclic hemicyanine dye according to claim 1, characterized in that: The method uses 5-formaldehyde furan-2-boric acid as a starting material, first condenses with an indole quaternary ammonium salt to prepare a semicyanine, and then reacts with o-aminophenol and its derivatives to finally synthesize a borate tricyclic semicyanine product; the method comprises the following steps: Step 1, 5-formaldehyde furan-2-boric acid A and 0.2 to 1 times the amount of a heterocyclic compound B are dissolved in a solvent, 0.01 to 5 times the amount of a base is used as a catalyst, and the above multiples are based on 5-formaldehyde furan-2-boric acid A, reacting at 60 to 140° C. for 1 to 12 hours to obtain a crude product C, and removing the solvent to obtain a compound C; Step 2, compound C is mixed with 0.5 to 3 times the amount of o-aminophenol or its derivative D in a solvent, the above multiples are based on compound C, reacted at 0 to 70° C. for 5 to 60 minutes, the solvent is removed, and pure compound E, i.e., borate tricyclic semicyanine dye, is obtained by column chromatography; The heterocyclic B compound is selected from: Or other aromatic substituted heterocyclic structure compounds having active methyl or active methylene groups; aromatic substituted heterocyclic structures having active methylene groups are selected from the following, wherein the carbon within the dotted circle is used to form a double bond: O-aminophenol or its derivatives D are selected from: Or other compounds in which the hydroxyl group and the amino group are ortho positions; the structures of other compounds in which the hydroxyl group and the amino group are ortho positions are selected from the following:

3. The method according to claim 2, characterized in that In step 1, the solvent required for the reaction is ethanol, methanol, acetonitrile, dichloromethane, acetone, etc., and the base required is piperidine, pyridine, triethylamine, etc.

4. The method according to claim 2, characterized in that In step 2, Y in the structural formula - is an anion selected from halogen ions, PF6 - 、ClO4 - , TsO - wait.

5. The method for preparing the borate tricyclic hemicyanine dye according to claim 1, characterized in that: 5-formaldehyde furan-2-boric acid is used as a starting material, firstly condensed with an aniline or its derivative to prepare an imine compound, then reacted with o-aminophenol or its derivative, and finally added with a base and an indole quaternary ammonium salt for substitution reaction, and finally synthesized a borate tricyclic semicyanine product; specifically including the following: Step 1, 5-formaldehyde furan-2-boric acid A and 0.2 to 1 times the amount of aniline or its derivative F are dissolved in a solvent, the above multiples are based on 5-formaldehyde furan-2-boric acid A, react at 0 to 70° C. for 1 to 12 hours to obtain an intermediate product G, continue to add 0.5 to 3 times the amount of o-aminophenol or its derivative D in a solvent, the above multiples are based on compound A, react at 0 to 70° C. for 1 to 12 hours, and evaporate the solvent under reduced pressure to obtain a crude product H; Step 2, the crude product H and 0.5 to 3 times the amount of the heterocyclic compound B are mixed in an alkaline solution, the above multiples are based on the compound H, react at 40 to 120° C. for 1 to 12 hours, remove the solvent, and obtain a pure compound E, i.e., a borate tricyclic semicyanine dye, through column chromatography.

6. The method according to claim 5, characterized in that In step 1, the solvent required for the reaction is selected from ethanol, methanol, acetonitrile, dichloromethane, acetone, etc. The o-aminophenol or its derivative D is consistent with that in claim 2.

7. The method according to claim 5, characterized in that In step 2, the solvent required for the reaction is selected from ethanol, methanol, acetonitrile, dichloromethane, acetone, etc., and the base required is selected from piperidine, pyridine, triethylamine, etc.; heterocycle B is consistent with claim 2.

8. The use of the borate tricyclic hemicyanine dye according to claim 1, characterized in that: Application as fluorescent material.

9. Use of the borate tricyclic hemicyanine dye according to claim 1, wherein the dye having a nitro group on R1 is also used in nitroreductase detection.

Images