Preparation method and application of dehydroabietic acid-based D-A type polarity response fluorescent compound

Abstract

The invention relates to the technical field of dehydroabietic acid-based compounds, and particularly discloses a preparation method and application of a dehydroabietic acid-based D-A type polarity response fluorescent compound, the compound is dehydroabietic acid thiadiazole-carbazole, dehydroabietic acid thiadiazole-triphenylamine, dehydroabietic acid thiadiazole-dimethylaniline and dehydroabietic acid thiadiazole-phenoxazine; the dehydroabietic acid-based D-A fluorescent compound is obtained by introducing groups with different electron donating capacities to a natural source receptor dehydroabietic acid thiadiazole, and the dehydroabietic acid-based D-A fluorescent compound is developed for the first time; the dehydroabietic acid-based D-A type fluorescent compound shows good fluorescence performance, fluorescence wavelength red shift is increased along with electron donating ability, and meanwhile, the dehydroabietic acid-based D-A type fluorescent compound also has good polarity response performance; wherein the specific targeting lipid droplet is realized by virtue of good biocompatibility and a steroid-like skeleton structure of the dehydroabietic acid thiadiazole-dimethylaniline, and the specific targeting lipid droplet can be used as a fluorescent probe to have application potential in the field of biological imaging and has very good practicability.

Description

Technical Field

[0001] The invention relates to the technical field of dehydroabietic acid-based compounds, and in particular to a preparation method of a dehydroabietic acid-based DA-type polarity-responsive fluorescent compound and a biological imaging application thereof. Background Art

[0002] Natural products have attracted people's attention due to their unique pharmacological properties, renewable degradation, excellent biocompatibility and other advantages. Among them, the simple structure of the natural small molecule dehydroabietic acid can construct a steroidal analogue with a four-ring structure, thereby constructing a bio-based aggregation-induced emission (BioAIE) material. Rosin comes from natural rosin and is a renewable resource containing a benzene ring, an alicyclic ring and an oxygen atom structure. It has good biocompatibility and its derivatives have broad biological application prospects. [Xu-Min Cai, Yuting Lin, Ying Li, et al. Nature Communications, 2021, 12 (1), 1773.]. Thanks to the diversity and easy modification of electron donors, regulation based on electron donors has become the dominant design strategy for constructing DA-type fluorescent molecules. However, the types of electron acceptors are relatively limited, mainly concentrated in naphthalene imide, imidazole, benzothiadiazole, etc. Common acceptor structures all come from fossil fuels, and there are very few studies on natural acceptors. [Aiyan Ji, Hongyue Lou, Chunrong Qu, et al. Nature Communications, 2022, 13(1), 3815.] Therefore, it is of great significance to develop new natural A-constructed polar-responsive natural DA-type BioAIE materials.

[0003] Fluorescent probes have been widely used in biomedical fields, such as physiological imaging, environmental monitoring, clinical diagnosis, etc. It is well known that local environmental parameters (such as polarity, viscosity, pH) in biological systems play a key role in regulating transport, diffusion, and intermolecular interactions. Abnormal changes in these parameters are closely related to certain physiological disorders or diseases. [Xiaojun Qin, Xingye Yang, Lupei Du, et al. RSC Medical Chemistry, 2021, 12, 1826-1838.]. At present, small molecule fluorescent probes have the advantages of real-time detection, high sensitivity and high specificity, and have been widely developed in monitoring dynamic cell polarity. Fluorescent probes currently used for lipid droplet imaging face major limitations, such as small Stokes shift and low quantum yield. [Rikitha S Fernandes, Ambati Himaja, Balaram Ghosh, et al. ACS Applied Bio Materials, 2024, 7, 12, 8248-8260]. Therefore, it is very desirable to develop high-performance probes for detecting lipid droplet polarity. Summary of the invention

[0004] In view of the above-mentioned problems, the present invention aims to provide a dehydroabietic acid-based DA-type polar-responsive fluorescent compound, a preparation method and biological imaging application thereof.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows: a dehydroabietic acid-based DA-type polar response fluorescent compound, the structural formula of which is as follows:

[0006]

[0007] Wherein, R is selected from N-phenylcarbazole or triphenylamine, N,N-dimethylaniline or phenoxazine.

[0008] The dehydroabietic acid-based DA-type polarity-responsive fluorescent compound of the present invention preferably has R as N,N-dimethylaniline; the preferred dehydroabietic acid thiadiazole-dimethylaniline has excellent polarity-sensitive properties and can be used for specific targeting of lipid droplets.

[0009] The present invention provides a method for preparing a dehydroabietic acid-based DA-type polar response fluorescent compound, comprising the following steps:

[0010] Step 1) coupling dehydroabietic acid thiadiazole with 4-(9H-carbazole-9-yl)phenylboronic acid to obtain compound I: dehydroabietic acid thiadiazole-carbazole;

[0011]

[0012] Step 2) coupling dehydroabietic acid thiadiazole with 4-(diphenylamino)phenylboronic acid to obtain compound II: dehydroabietic acid thiadiazole-triphenylamine;

[0013]

[0014] Step 3) coupling dehydroabietic acid thiadiazole with 4-(N,N-dimethylamino)phenylboronic acid pinacol ester to obtain compound III: dehydroabietic acid thiadiazole-dimethylaniline;

[0015]

[0016] Step 4) coupling dehydroabietic acid thiadiazole with phenoxazine to obtain compound IV: dehydroabietic acid thiadiazole-phenoxazine;

[0017]

[0018] The Suzuki coupling reactions in steps 1), 2) and 3) of the preparation method of the present invention are all carried out in an organic solvent under oxygen-free and alkaline conditions, and the catalyst is tetrakis(triphenylphosphine)palladium, which is prepared by heating.

[0019] In the Suzuki coupling reaction of steps 1), 2) and 3) of the preparation method of the present invention, the organic solvent is toluene, the alkaline environment is a potassium carbonate aqueous solution, the heating temperature is 115-120° C., and the reaction time is 6-8 hours.

[0020] In the Suzuki coupling reaction of steps 1), 2) and 3) of the preparation method of the present invention, the molar ratio of dehydroabietic acid thiadiazole to 4-(9H-carbazole-9-yl)phenylboronic acid or 4-(diphenylamino)phenylboronic acid or 4-(N,N-dimethylamino)phenylboronic acid pinacol ester is 1.2:1-1; and the molar ratio of 4-(9H-carbazole-9-yl)phenylboronic acid or 4-(diphenylamino)phenylboronic acid or 4-(N,N-dimethylamino)phenylboronic acid pinacol ester to the catalyst is 25:1.

[0021] The Buchwald-Hartwig coupling reaction in step 4) of the preparation method of the present invention is carried out in an organic solvent under oxygen-free and alkaline conditions, and the catalyst is tris(dibenzylacetone)dipalladium and tri-tert-butylphosphine tetrafluoroborate, which is prepared by heating.

[0022] In the Buchwald-Hartwig coupling reaction of step 4) of the preparation method of the present invention, the organic solvent is toluene, the alkaline environment is sodium tert-butoxide, and the heating temperature is 115-120°C.

[0023] In the Buchwald-Hartwig coupling reaction of step 4) of the preparation method of the present invention, the molar ratio of dehydroabietic acid thiadiazole to phenoxazine is 1.2:1-1; and the molar ratio of phenoxazine to the catalyst is 25:1.

[0024] The present invention provides an application of a dehydroabietic acid-based DA-type polar response fluorescent compound in biological imaging, wherein R in the compound is N,N-dimethylaniline. The application in biological imaging specifically refers to: Compound III can specifically target lipid droplets, and the Pearson correlation coefficient is 0.91.

[0025] The advantages of the present invention are as follows: the compounds of the present invention are the first to develop polar responsive fluorescent compounds based on dehydroabietic acid DA type, and the introduction of groups with different electron donating abilities creates conditions for studying the structure-activity relationship of dehydroabietic acid DA type compounds; the series of dehydroabietic acid DA type compounds based on the new natural source electron acceptor all have good fluorescence properties and the fluorescence wavelength red shifts with the increase of electron donating ability, and also have good polar response properties; specific targeting of lipid droplets is achieved based on the good biocompatibility and steroid-like skeleton structure of dehydroabietic acid thiadiazole-dimethylaniline. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is the H NMR spectrum of compound (I);

[0027] Figure 2 is the H NMR spectrum of compound (II);

[0028] Figure 3 is the H NMR spectrum of compound (III);

[0029] Figure 4 is the H NMR spectrum of compound (IV);

[0030] Figure 5 (a) is the UV-visible absorption spectrum of compound (II); (b) is the fluorescence spectrum of different water contents;

[0031] Figure 6 (a) is the UV-visible absorption spectrum of compound (II); (b) is the fluorescence spectrum of different water contents;

[0032] Figure 7 (a) is the UV-visible absorption spectrum of compound (III); (b) is the fluorescence spectrum of different water contents;

[0033] Figure 8 (a) is the UV-visible absorption spectrum of compound (IV); (b) is the fluorescence spectrum of different water contents;

[0034] Fig. 9 is a normalized solid-state fluorescence spectrum of compound (I), compound (II), compound (III) and compound (IV);

[0035] Fig.10 (a) is the fluorescence spectra of compound (III) in solvents with different polarities; (b) is the fluorescence lifetime spectra in solvents with different polarities;

[0036] Fig.11 Confocal imaging of lipid droplets for compound (III);

[0037] Fig.12 It is a comparison chart of the polarity response performance of compound (III) and DAMB-SAN;

[0038] Fig.13 It is a comparison chart of quantum yields of compound (III) and DAMB-SAN;

[0039] Fig.14 This is a comparison chart of the polarity response performance of compound (III) and intermediate DABT-Br;

[0040] Fig.15 The figure is a comparison chart of the quantum yields of compound (III) and intermediate DABT-Br. DETAILED DESCRIPTION

[0041] The present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0042] Example 1: Synthesis of dehydroabietic acid thiadiazole-carbazole (I)

[0043] Under nitrogen, 0.5 mmol of dehydroabietic acid thiadiazole intermediate, 0.5 mmol of 4-(9H-carbazole-9-yl)phenylboronic acid and 0.02 mmol of tetrakis(triphenylphosphine)palladium catalyst were added in sequence, and then 2 mL of dry toluene and 1 mL of 2 mol / L potassium carbonate solution were slowly added, and the mixture was heated and stirred at 115°C for 6 h. After the reaction was completed, the mixture was cooled to room temperature, extracted with dichloromethane 3 times, and the organic phase was washed once with a saturated sodium chloride aqueous solution, dried and filtered, and the filtrate was distilled under reduced pressure to remove toluene to obtain an oily crude product. Compound (I) was obtained as a white solid by silica gel column chromatography (eluent: petroleum ether / ethyl acetate, volume ratio: 15:1), with a yield of 65%. Melting point: 303.3-304.5°C.

[0044] Compound I 1 H-NMR (CDCl3, δ / ppm, 600MHz) spectrum is as follows Figure 1: 8.18-8.14 (m, 4H), 7.81 (s, 1H), 7.74 (d, J = 6.9 Hz, 2H), 7.61-7.55 (m, 2H), 7.44 (m, 2H), 7.31 (m, 2H), 3.74-3.69 (m, 3H), 3.48-3.45 (m, 1H), 3.30-3.2 5 (m, 1H), 2.53 (d, J = 11.8Hz, 1H), 2.44 (d, J = 12.1Hz, 1H), 2.00 (m, 1H), 1.92- 1.84 (m, 3H), 1.74 (d, J=10.9Hz, 1H), 1.67 (m, 2H), 1.41 (s, 3H), 1.37 (s, 3H).

[0045] The above NMR characterization results show that dehydroabietic acid thiadiazole-carbazole was obtained, and its structure is as follows:

[0046]

[0047] Example 2: Synthesis of dehydroabietic acid thiadiazole-triphenylamine (II)

[0048] Under nitrogen, 0.5 mmol of compound (V), 0.5 mmol of 4-(diphenylamino)phenylboronic acid and 0.02 mmol of tetrakis(triphenylphosphine)palladium catalyst were added in sequence, and then 2 mL of dry toluene and 1 mL of 2 mol / L potassium carbonate solution were slowly added, and the mixture was heated and stirred at 115°C for 6 h. After the reaction was completed, the mixture was cooled to room temperature, extracted with dichloromethane 3 times, and the organic phase was washed once with a saturated sodium chloride aqueous solution, dried and filtered, and the filtrate was distilled under reduced pressure to remove toluene to obtain an oily crude product. Compound (II) was obtained as a yellow solid by silica gel column chromatography (eluent: petroleum ether / ethyl acetate, volume ratio: 15:1), with a yield of 70%. Melting point: 208.0-208.6°C.

[0049] Compound II 1 H-NMR (CDCl3, δ / ppm, 600MHz) spectrum is as follows Figure 1: 7.77 (d, J = 6.8 Hz, 2H), 7.63 (s, 1H), 7.26 (s, 4H), 7.17 (s, 6H), 7.03 (s, 2H), 3.69 (s, 3H), 3.39 (d, J = 16.9 Hz, 1H), 3.22-3.18 (m, J = 24.2 Hz, 1H), 2.44 ( d, J=12.0Hz, 1H), 2.37 (d, J=12.0Hz, 1H), 1.93 (s, 1H), 1.86-1.76 (m, J=62.8 Hz, 3H), 1.69 (d, J=8.6Hz, 1H), 1.61-1.57 (m, 2H), 1.33 (s, 3H), 1.32 (s, 3H).

[0050] The above NMR characterization results show that dehydroabietic acid thiadiazole-triphenylamine was obtained, and its structure is as follows:

[0051]

[0052] Example 3: Synthesis of dehydroabietic acid thiadiazole-dimethylaniline (III)

[0053] Under nitrogen, 0.5 mmol of compound (V), 0.5 mmol of 4-(N, N-dimethylamino)phenylboronic acid pinacol ester and 0.02 mmol of tetrakis(triphenylphosphine)palladium catalyst were added in sequence, and then 2 mL of dry toluene and 1 mL of 2 mol / L potassium carbonate solution were slowly added, and the mixture was heated and stirred at 115°C for 6 h. After the reaction was completed, the mixture was cooled to room temperature, extracted with dichloromethane 3 times, and the organic phase was washed once with a saturated sodium chloride aqueous solution, dried and filtered, and the filtrate was distilled under reduced pressure to remove toluene to obtain an oily crude product. Compound (III) was obtained as an orange solid by silica gel column chromatography (eluent: petroleum ether / ethyl acetate, volume ratio: 15:1), with a yield of 50%. Melting point: 149.3-150.2°C.

[0054] Compound III 1 H-NMR (CDCl3, δ / ppm, 600MHz) spectrum is as follows Figure 3Shown: 7.82 (d, J=8.6Hz, 2H), 7.61 (s, 1H), 6.88 (d, J=8.6Hz, 2H), 3.71 (s, 3H), 3 .41-3.37(m, 1H), 3.23-3.17(m, 1H), 3.03(s, 6H), 2.45(d, J=12.9Hz, 1H), 2. 39(d, J=12.2Hz, 1H), 1.98-1.91(m, 1H), 1.88-1.77(m, 3H), 1.69-1.63(d, J= 10.7Hz, 1H), 1.62 (d, J=11.9Hz, 1H), 1.60 (s, 1H), 1.35 (s, 3H), 1.34 (s, 3H).

[0055] The above NMR characterization results show that dehydroabietic acid thiadiazole-dimethylaniline was obtained, and its structure is as follows:

[0056]

[0057] Example 4: Synthesis of dehydroabietic acid thiadiazole-phenoxazine (IV)

[0058] Under nitrogen, 0.5 mmol of compound (V), 0.5 mmol of phenoxazine and 0.02 mmol of tris(dibenzylideneacetone)dipalladium(0) catalyst, 0.5 mmol of sodium tert-butoxide, 0.25 mmol of tri-tert-butylphosphine tetrafluoroborate were added in sequence, and then 2 mL of dry toluene solution was slowly added, and the mixture was heated and stirred at 115°C for 6 h. After the reaction was completed, the mixture was cooled to room temperature, extracted with dichloromethane 3 times, and the organic phase was washed once with a saturated sodium chloride aqueous solution, dried and filtered, and the filtrate was distilled under reduced pressure to remove toluene to obtain an oily crude product. Compound (IV) was obtained as a red solid by silica gel column chromatography (eluent: petroleum ether / ethyl acetate, volume ratio: 15:1), with a yield of 55%. Melting point: 213.8-214.4°C.

[0059] Compound IV 1 H-NMR (CDCl3, δ / ppm, 600MHz) spectrum is as follows Figure 3 Shown: 7.69 (s, 1H), 6.75 (d, J = 7.9Hz, 2H), 6.68-6.65 (m, 2H), 6.55-6.52 (m, 2H), 5.79 (d, J = 8.0Hz, 2H), 3.73 (s, 3H), 3.49-3.45 ( m, 1H), 3.31-3.24 (m, 1H), 2.42 (d, J=12.5Hz, 1H), 2.32-2.26 (m, 1H), 2.02-1.94 (m, 1H), 1.84-1.66 (m, 5H), 1.43-1.34 (m, 7H).

[0060] The above NMR characterization results show that dehydroabietic acid thiadiazole-phenoxazine is obtained, and its structure is as follows:

[0061]

[0062] Example 5: Determination of the aggregation-induced emission (AIE) optical properties of the dehydroabietic acid-based DA fluorescent compound I.

[0063] In THF / H2O medium with different ratios, the concentration of dehydroabietic acid DA type fluorescent compound I was fixed at 10 μmol / L, and the fluorescence spectrum was analyzed by UV-visible spectrophotometer and fluorescence spectrometer (excitation wavelength was 373 nm). The fluorescence spectrum of the obtained compound 1 is shown in Figure 5 .

[0064] from Figure 5 (a) It can be seen that compound I has an obvious CT peak, and its maximum absorption wavelength is at 373 nm.

[0065] from Figure 5 (b) It can be seen that due to the twisted intramolecular charge transfer performance of compound I, when the medium is at a low water content (0%-60%), the emission wavelength gradually red-shifts and the fluorescence intensity weakens, and when the medium is at a high water content (70%-99%), the emission wavelength blue-shifts and the fluorescence intensity enhances, indicating that compound I has TICT-AIE characteristics.

[0066] Example 6: Determination of the aggregation-induced emission (AIE) optical properties of the dehydroabietic acid-based DA fluorescent compound II.

[0067] In THF / H2O medium with different ratios, the concentration of dehydroabietic acid DA type fluorescent compound I was fixed at 10 μmol / L, and the fluorescence spectrum was analyzed by UV-visible spectrophotometer and fluorescence spectrometer (excitation wavelength was 411 nm). The fluorescence spectrum of the obtained compound 1 is shown in Figure 6 .

[0068] from Figure 6 (a) It can be seen that compound II has an obvious CT peak, and its maximum absorption wavelength is at 411 nm.

[0069] from Figure 6 (b) It can be seen that the compound II has a twisted intramolecular charge transfer property. When the medium is at a low water content (0%-60%), the emission wavelength gradually red-shifts and the fluorescence intensity weakens. When the medium is at a high water content (70%-99%), the emission wavelength blue-shifts and the fluorescence intensity increases, indicating that compound II has TICT-AIE characteristics.

[0070] Example 7: Determination of the optical properties of the aggregation-induced emission (AIE) performance of the dehydroabietic acid-based DA-type fluorescent compound III.

[0071] In THF / H2O medium with different ratios, the concentration of dehydroabietic acid DA type fluorescent compound III was fixed at 10 μmol / L, and the fluorescence spectrum was analyzed by UV-visible spectrophotometer and fluorescence spectrometer (excitation wavelength was 424 nm). The fluorescence spectrum of the obtained compound III is shown in Figure 5 .

[0072] from Figure 7 (a) It can be seen that compound III has an obvious CT peak, and its maximum absorption wavelength is at 424 nm.

[0073] from Figure 7 (b) It can be seen that the compound III has a twisted intramolecular charge transfer property. When the medium is at a low water content (0%-70%), the emission wavelength gradually red-shifts and the fluorescence intensity weakens. When the medium is at a high water content (80%-99%), the emission wavelength blue-shifts and the fluorescence intensity increases, indicating that compound II has TICT-AIE characteristics.

[0074] Example 8: Determination of the optical properties of the aggregation-induced emission (AIE) performance of the dehydroabietic acid-based DA-type fluorescent compound IV.

[0075] In THF / H2O medium with different ratios, the concentration of dehydroabietic acid DA type fluorescent compound IV was fixed at 10 μmol / L, and the fluorescence spectrum was analyzed by UV-visible spectrophotometer and fluorescence spectrometer (excitation wavelength was 314 nm). The fluorescence spectrum of compound IV is shown in Figure 5 .

[0076] from Figure 8 (a) It can be seen that the maximum absorption wavelength of compound IV is at 314 nm.

[0077] from Figure 8 (b) It can be seen that as the water content of the medium increases, the fluorescence intensity increases, indicating that compound Iv has AIE properties.

[0078] Example 9: Determination of optical properties of dehydroabietic acid-based DA-type fluorescent compounds in the solid state.

[0079] The fluorescence spectrum of the obtained dehydroabietic acid-based DA type fluorescent compound is analyzed by fluorescence spectrometer. Fig. 9 .

[0080] from Fig. 9It can be seen that as the electron donating ability of compound I, compound II, compound III and compound IV increases, the emission wavelength of the solid shows a trend of red shift.

[0081] Example 10: Determination of polar response performance of dehydroabietic acid-based DA-type fluorescent compound III.

[0082] In different polar solvents (cyclohexane, ethyl acetate, acetone and dimethyl sulfoxide), the concentration was fixed at 10 μmol / L, and the fluorescence spectra of the obtained compound III were analyzed by fluorescence spectrometer. Fig.10 .

[0083] from Fig.10 (a) It can be seen that as the polarity of the solvent increases, the emission wavelength of the compound III red-shifts from 516 nm (cyclohexane) to 668 nm (dimethyl sulfoxide), a red-shift of 152 nm, and has a sensitive polarity response.

[0084] from Fig.10 (b) It can be seen that as the polarity of the solvent increases, the fluorescence lifetime of compound III decreases from 10.8 ns (cyclohexane) to 1.9 ns (dimethyl sulfoxide), which has a certain regular trend and can be potentially used as a fluorescent probe to monitor polarity changes in biological microenvironments.

[0085] Example 11: Application of dehydroabietic acid-based DA-type fluorescent compound III in lipid droplet imaging.

[0086] HeLa cells were cultured in DMEM or RPMI1640 medium supplemented with 10% fetal bovine serum, 100ug mL -1 Streptomycin and 100U mL -1 Penicillin. Cells were cultured in a humidified incubator at 37°C in an atmosphere of 5% CO2 and 95% air (normoxia, 5% CO2).

[0087] HeLa cells were inoculated in Corning culture dishes for 24 h and then incubated with compound (III) (20 uM). Deep Red FM (LTDR, 200nM) or The cells were stained with Green FM (MTG, 200 nM) for 15 minutes. The cells were washed twice with PBS and immediately imaged with a confocal microscope to obtain fluorescence images. Compound (III): λ ex =405nm,λ em =590±20nm; LIPDR:λ ex =640nm,λ em=680±20nm; LTDR:λ ex =633nm; λ em =720±20nm;MTG:λ ex =488nm,λ em =510±20nm. Fig.10 It can be seen that compound (III) can highly overlap with LIPDR and can specifically target lipid droplets, with a Pearson correlation coefficient of 0.91. The ability of compound III to target lysosomes and mitochondria is relatively weak (LTDR: 0.74, MTG: 0.58).

[0088] Comparative Example 1:

[0089] Compared with the DAMB-SAN molecule (as shown in Formula VI) in the literature [Xu-Min Cai, Yuting Lin, Ying Li, et al. Nature Communications, 2021, 12(1), 1773.], the difference is that compound (III) has good polarity response performance, while DAMB-SAN has no polarity response performance. Fig.12 shown.

[0090] Comparative Example 2:

[0091] Compared with the DAMB-SAN molecule in the literature [Xu-Min Cai, Yuting Lin, Ying Li, et al. Nature Communications, 2021, 12(1), 1773.], the difference is that compound (III) has a stronger quantum yield of 54.5%, while the quantum yield of DAMB-SAN is 4.9%, such as Fig.13 shown.

[0092] Comparative Example 3:

[0093] Compared with the intermediate DABT-Br, the difference is that compound (III) has a good polarity response performance, while DABT-Br has a weak polarity response performance. Fig.14 shown.

[0094] Comparative Example 4:

[0095] Compared with the intermediate DABT-Br, the difference is that compound (III) has a stronger quantum yield of 54.5%, while the quantum yield of DABT-Br is 0%. Fig.15 shown.

[0096]

[0097] It should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any combination or equivalent transformation made on the basis of the above embodiments shall fall within the protection scope of the present invention.

Claims

1. A dehydroabietic acid-based DA-type polar response fluorescent compound, characterized in that: Its structural formula is as follows: Wherein, R is selected from N-phenylcarbazole triphenylamine, N,N-dimethylaniline or phenoxazine.

2. The fluorescent compound according to claim 1, characterized in that The R is N,N-dimethylaniline.

3. A method for preparing the fluorescent compound according to claim 1, characterized in that: The following steps are involved: Step 1) coupling dehydroabietic acid thiadiazole with 4-(9H-carbazole-9-yl)phenylboronic acid to obtain compound I: dehydroabietic acid thiadiazole-carbazole; Step 2) coupling dehydroabietic acid thiadiazole with 4-(diphenylamino)phenylboronic acid to obtain compound II: dehydroabietic acid thiadiazole-triphenylamine; Step 3) coupling dehydroabietic acid thiadiazole with 4-(N,N-dimethylamino)phenylboronic acid pinacol ester to obtain compound III: dehydroabietic acid thiadiazole-dimethylaniline; Step 4) coupling dehydroabietic acid thiadiazole with phenoxazine to obtain compound IV: dehydroabietic acid thiadiazole-phenoxazine; 4. The preparation method according to claim 3, characterized in that: The steps 1), 2) and 3) are Suzuki coupling reactions, all of which are carried out in an organic solvent under oxygen-free and alkaline conditions, and the catalyst is tetrakis(triphenylphosphine)palladium, which is prepared by heating.

5. The preparation method according to claim 4, characterized in that: The organic solvent is toluene, the alkaline environment is potassium carbonate aqueous solution, the heating temperature is 115-120° C., and the reaction time is 6-8 hours.

6. The preparation method according to claim 4, characterized in that: The molar ratio of the dehydroabietic acid thiadiazole to 4-(9H-carbazole-9-yl)phenylboronic acid or 4-(diphenylamino)phenylboronic acid or 4-(N,N-dimethylamino)phenylboronic acid pinacol ester is 1.2:1-1; The molar ratio of 4-(9H-carbazole-9-yl)phenylboronic acid or 4-(diphenylamino)phenylboronic acid or 4-(N,N-dimethylamino)phenylboronic acid pinacol ester to the catalyst is 25:

1.

7. The preparation method according to claim 3, characterized in that: The step 4) is a Buchwald-Hartwig coupling reaction, which is carried out in an organic solvent under oxygen-free and alkaline conditions, and the catalyst is tris(dibenzylacetone)dipalladium and tri-tert-butylphosphine tetrafluoroborate, which is prepared by heating.

8. The preparation method according to claim 7, characterized in that: The organic solvent is toluene, the alkaline environment is sodium tert-butoxide, and the heating temperature is 115-120°C.

9. The preparation method according to claim 7, characterized in that: The molar ratio of dehydroabietic acid thiadiazole to phenoxazine is 1.2:1-1; The molar ratio of phenoxazine to catalyst is 25:

1.

10. Use of the fluorescent compound according to claim 2 in biological imaging.

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