Myl-1 compound for labeling myelin in central nervous system, and preparation method therefor and use thereof

Abstract

The present invention belongs to the technical field of organic compound synthesis, and specifically relates to an MyL-1 compound for labeling a myelin in a central nervous system and a preparation method therefor. The MyL-1 compound has a structure as shown in formula (1). The key of the present invention is that an O-B-O-type BODIPY derivative molecule is used as a raw material, and a flexible ester group is introduced at the molecule terminal, so that the MyL-1 compound obtained therefrom can successfully label a myelin substance in a brain model with high specificity, and has excellent photostability and a good spatial resolution. The myelin ultra-microstructure can be constructed under a stimulated emission depletion nano microscope, and the myelin structure in a brain tissue can be directly visualized, thereby opening up a new method for direct and non-invasive research and understanding of the complex process of myelin formation.

Description

A MyL-1 compound for myelin labeling in the central nervous system, and its preparation method and application Technical Field

[0001] The invention belongs to the technical field of organic compound synthesis, and particularly relates to a MyL-1 compound for marking myelin sheaths in the central nervous system, and a preparation method and application thereof. Background Art

[0002] The integrity of the mammalian nervous system is essential for proper information transmission between and within neurons. This process is critically dependent on myelination, the formation of a lipid-rich substance (sphingomyelin) to insulate neuronal axons. The evolution of cognitive and motor skills is closely linked to the successful formation and development of myelin from infancy to maturity. Loss of myelin, also known as demyelination, can directly lead to a rapid decrease in the speed of neuronal electrical impulses, a hallmark of neurodegenerative diseases and inherited demyelinating disorders. Understanding the ultrastructure of myelin, particularly its dynamics during development, is of great significance to neuroscience and clinical diagnosis.

[0003] Currently, the most commonly used technique for observing myelin structure is electron microscopy, which can achieve nanometer-scale resolution. However, electron microscopy suffers from the difficulty of quantitatively measuring large-scale and three-dimensional images, and information delays increase the workload. Recent advances in super-resolution nanomicroscopy, such as stimulated emission depletion (SED), structured illumination microscopy, and stochastic optical reconstruction microscopy, have made it possible to observe myelin ultrastructure in vivo. Commercial probes for myelin structure are extremely rare, and none of these are suitable for highly sensitive super-resolution nanomicroscopy. Existing studies typically use indirect methods involving staining for myelin basic protein to observe myelin structure, which is unable to visualize myelin's three-dimensional structure. In summary, an ideal myelin-labeling probe should combine high specificity for parenchymal tissue sphingomyelin with high resilience to intense laser irradiation, thereby enabling reconstruction of myelin's three-dimensional ultrastructure under super-resolution nanomicroscopy. Summary of the Invention

[0004] The first aspect of the present invention is to address the above technical problems and propose a MyL-1 compound for labeling myelin in the central nervous system. The MyL-1 compound can successfully label myelin substances in brain models with high specificity and has excellent photostability, and can directly display the myelin ultrastructure under stimulated emission depletion nanoscopy.

[0005] The second aspect of the present invention is to provide a method for preparing the MyL-1 compound for use in myelin sheath labeling in the central nervous system.

[0006] The third aspect of the present invention is to provide a MyL-1 compound prepared by the above method for use in myelin labeling in the central nervous system.

[0007] The fourth aspect of the present invention is to provide the use of the MyL-1 compound in biological monitoring.

[0008] Specifically, the MyL-1 compound for myelin labeling in the central nervous system provided by the present invention has a structure shown in formula (1);

[0009] In formula (1), R1 and R2 are each independently a C0-C4 alkylene group.

[0010] The preparation method of the MyL-1 compound comprises condensing 4-[bis[2-(acetyloxy)ethyl]amino]benzaldehyde having a structure represented by formula (2) and an OBO-type BODIPY derivative having a structure represented by formula (3) in the presence of a catalyst to obtain the MyL-1 compound;

[0011] In formula (3), R3 and R4 are each independently a C1-C5 alkyl group.

[0012] In a preferred embodiment, the usage ratio of the 4-[bis[2-(acetoxy)ethyl]amino]benzaldehyde, the OBO-type BODIPY derivative and the catalyst is (2-2.5) mol:1 mol:(40-80) mL.

[0013] In a preferred embodiment, the temperature of the condensation reaction is 60-80°C.

[0014] In a preferred embodiment, the condensation reaction time is 10-12 hours.

[0015] In a preferred embodiment, the OBO-type BODIPY derivative is obtained by reacting an alkyl diketone compound having a structure represented by formula (4) with boron trifluoride etherate;

[0016] In formula (4), R3 and R4 are each independently a C1-C5 alkyl group.

[0017] In a preferred embodiment, the molar ratio of the alkyl diketone compound to boron trifluoride etherate is 1:(1.1-1.5).

[0018] In a preferred embodiment, the reaction temperature is 50-70°C.

[0019] In a preferred embodiment, the reaction time is 5 to 7 hours.

[0020] In a preferred embodiment, the reaction conditions of the condensation reaction further include being carried out in the presence of a dehydrating agent.

[0021] In a preferred embodiment, the amount of the dehydrating agent added is 1-5 mL.

[0022] In a preferred embodiment, the dehydrating agent is selected from at least one of tributyl borate, triethyl borate and trimethyl borate.

[0023] In a preferred embodiment, the catalyst is selected from at least one of n-butylamine, di-n-butylamine and triethylamine.

[0024] The key to this invention lies in using an OBO-type BODIPY derivative as a raw material and introducing a flexible ester group at the end of the molecule. The resulting MyL-1 compound can successfully label myelin in brain models with high specificity and exhibits excellent photostability, enabling the reconstruction of myelin ultrastructure under stimulated emission depletion nanoscopy. Furthermore, the MyL-1 compound exhibits excellent spatial resolution, enabling three-dimensional imaging under super-resolution microscopy. In summary, the MyL-1 compound can directly visualize myelin structure in brain tissue, opening up a new avenue for direct and non-invasive study and understanding of the complex process of myelination, and paving the way for further advancements in the field of nanoscale neuroimaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG1 is a spectrum of the MyL-1 compound prepared in Example 1.

[0026] FIG2 is a fluorescence response diagram of the MyL-1 compound prepared in Example 1.

[0027] FIG3 is a graph showing the titration results of the MyL-1 compound prepared in Example 1.

[0028] FIG4 is a diagram of a molecular docking experiment of the MyL-1 compound prepared in Example 1.

[0029] FIG5 is a graph showing the Pearson coefficient of the MyL-1 compound prepared in Example 1.

[0030] FIG6 is a fluorescence co-localization image of the MyL-1 compound prepared in Example 1 and a commercial probe.

[0031] FIG7 is a fiber image of the MyL-1 compound prepared in Example 1 under a confocal microscope.

[0032] FIG8 is a three-dimensional image of the myelin sheath structure of the MyL-1 compound prepared in Example 1 under a 3D stimulated emission depletion microscope. DETAILED DESCRIPTION

[0033] The MyL-1 compound provided by the present invention for myelin labeling in the central nervous system has a structure shown in formula (1);

[0034] In formula (1), R1 and R2 are each independently a C0-C4 alkylene group, which may be exemplified by a single bond, a methylene group, an ethylene group, a n-propylene group, an isopropylene group, a n-butylene group, an isobutylene group, or a tert-butylene group.

[0035] In the present invention, the preparation method of the MyL-1 compound comprises condensing 4-[bis[2-(acetyloxy)ethyl]amino]benzaldehyde having a structure represented by formula (2) and an OBO-type BODIPY derivative having a structure represented by formula (3) in the presence of a catalyst to obtain the MyL-1 compound;

[0036] In formula (3), R3 and R4 are each independently a C1-C5 alkyl group, which can be exemplified by methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl or isopentyl.

[0037] In the preparation process of the MyL-1 compound, the condensation reaction temperature is preferably 60-80° C., such as 60° C., 62° C., 65° C., 68° C., 70° C., 72° C., 75° C., 78° C., 80° C., or any value therebetween. The condensation reaction time is preferably 10-12 h, such as 10 h, 10.2 h, 10.5 h, 10.8 h, 11 h, 11.2 h, 11.5 h, 11.8 h, 12 h, or any value therebetween.

[0038] In the preparation process of the MyL-1 compound, the condensation reaction can be carried out as follows: 4-[bis[2-(acetoxy)ethyl]amino]benzaldehyde having the structure represented by formula (2) is dissolved in an organic solvent. The OBO-type BODIPY derivative having the structure represented by formula (3) is added during stirring for 10-20 minutes. A catalyst is then added and the mixture is reacted at 60-80°C for 10-12 hours. After the mixture is cooled to room temperature, it is filtered to obtain a powder. The powder is then washed with an organic solvent at a temperature of 30-40°C, filtered while hot, and dried under vacuum to obtain the MyL-1 compound. Furthermore, the OBO-type BODIPY derivative can be added all at once or in two or three additions. The specific type of the organic solvent is not limited, as long as it can dissolve the raw materials. It can be selected from at least one of toluene, chlorobenzene, benzene, acetone, and triethanolamine.

[0039] In the present invention, the molar ratio of 4-[bis[2-(acetoxy)ethyl]amino]benzaldehyde, the OBO-type BODIPY derivative, and the catalyst is preferably (2-2.5) mol:1 mol:(40-80) mL. The molar ratio of 4-[bis[2-(acetoxy)ethyl]amino]benzaldehyde to the OBO-type BODIPY derivative is preferably (2-2.5):1, such as 2:1, 2.15:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, or any value therebetween. The molar ratio of the OBO-type BODIPY derivative to the catalyst is preferably 1 mol:(40-80) mL, such as 1 mol:40 mL, 1 mol:50 mL, 1 mol:60 mL, 1 mol:70 mL, 1 mol:80 mL, or any value therebetween.

[0040] In the present invention, the OBO-type BODIPY derivative can be prepared by reacting an alkyl diketone compound having a structure shown in formula (4) with boron trifluoride etherate;

[0041] In formula (4), R3 and R4 are each independently a C1-C5 alkyl group, specifically, at least one of a methyl group, an ethyl group, a propyl group, a butyl group, and a pentyl group. Preferably, the alkyl dione may be at least one of acetylacetone, 3,5-heptanedione, nonane-4,6-dione, undecane-5,7-dione, and tridecane-6,8-dione.

[0042] In the preparation process of the above-mentioned OBO-type BODIPY derivative, the molar ratio of the alkyl diketone compound to boron trifluoride ethyl ether is preferably 1:(1.1-1.5), such as 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, or any value therebetween. The reaction temperature is preferably 50-70°C, such as 50°C, 55°C, 60°C, 65°C, 70°C, or any value therebetween. The reaction time is preferably 5-7 hours, such as 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, or any value therebetween.

[0043] In a specific embodiment, the preparation steps of the OBO-type BODIPY derivative can be: reacting an alkyl diketone compound with boron trifluoride ether at 50-70° C. for 5-7 hours, cooling to room temperature, and standing overnight to precipitate block crystals. After filtering, rinse with anhydrous ether (2 mL×2), and then filter by suction to obtain light yellow flaky crystals, which are the OBO-type BODIPY derivative.

[0044] In the present invention, the condensation reaction can also be carried out in the presence of a dehydrating agent, wherein the amount of the dehydrating agent added is preferably 1-5 mL, such as 1 mL, 2 mL, 3 mL, 4 mL, 5 mL or any value therebetween. The dehydrating agent is preferably at least one selected from tributyl borate, triethyl borate and trimethyl borate.

[0045] The present invention will be described in detail below through specific examples.

[0046] Preparation Example 1

[0047] 100 mmol of acetylacetone and 150 mmol of boron trifluoride etherate were weighed and added to a 50 mL round-bottom flask. The mixture was reacted at 60°C for 6 h, cooled to room temperature, and allowed to stand overnight. Blocky crystals precipitated, which were filtered and rinsed with anhydrous ether (2 mL x 2). The resulting pale yellow flaky crystals were then filtered and filtered to obtain an OBO-type BODIPY derivative, designated A-1. IR and NMR analysis revealed that the OBO-type BODIPY derivative A-1 had the structure shown in formula (3), with R3 and R4 both being methyl groups.

[0048] Preparation Example 2

[0049] 100 mmol of acetylacetone and 110 mmol of boron trifluoride etherate were weighed and added to a 50 mL round-bottom flask. The mixture was reacted at 50°C for 7 h, cooled to room temperature, and allowed to stand overnight. Blocky crystals precipitated, which were filtered and rinsed with anhydrous ether (2 mL x 2). Afterwards, the mixture was filtered to obtain pale yellow flaky crystals, which were the OBO-type BODIPY derivative designated A-2. IR and NMR spectra showed that the OBO-type BODIPY derivative A-2 had the structure shown in formula (3), with R3 and R4 both being methyl groups.

[0050] Preparation Example 3

[0051] 100 mmol of acetylacetone and 125 mmol of boron trifluoride etherate were weighed and added to a 50 mL round-bottom flask. The mixture was reacted at 70°C for 5 h, cooled to room temperature, and allowed to stand overnight. Block crystals precipitated, which were filtered and rinsed with anhydrous ether (2 mL × 2). Then, light yellow flaky crystals were obtained by suction filtration, thereby obtaining an OBO-type BODIPY derivative, designated A-3. IR and NMR detection results showed that the OBO-type BODIPY derivative A-3 had the structure shown in formula (3), and R3 and R4 were both methyl groups.

[0052] Example 1 Preparation of MyL-1 compound

[0053] 10 mmol of 4-[bis[2-(acetoxy)ethyl]amino]benzaldehyde was dissolved in toluene. Subsequently, 5 mmol of the OBO-type BODIPY derivative A-1 was added in two portions and stirred for 10 minutes. Subsequently, 2.5 mL of tributyl borate and 0.3 mL of n-butylamine were added and the mixture was reacted at 60°C for 11 hours. After the mixture was cooled to room temperature, it was filtered to obtain a powder. The powder was then washed with toluene at 30°C, filtered while hot, and vacuum dried to obtain the MyL-1 compound. Infrared and nuclear magnetic resonance (NMR) detection results showed that the MyL-1 compound had the structure shown in formula (1), with R1 and R2 both being C0 (single bond). The spectrum of the MyL-1 compound is shown in Figure 1. The excitation and emission wavelengths of the compound MyL-1 were measured. The narrow peak range demonstrated its feasibility for optical imaging applications. The near-infrared excitation wavelength confirmed its feasibility for use in stimulated emission depletion super-resolution microscopy.

[0054] Example 2 Preparation of MyL-1 compound

[0055] 10 mmol of 4-[bis[2-(acetoxy)ethyl]amino]benzaldehyde was dissolved in toluene, and then 5 mmol of the OBO-type BODIPY derivative A-1 was added in three portions, stirred for 10 minutes, and then 2.5 mL of tributyl borate and 0.3 mL of n-butylamine were added. The mixture was reacted at 65°C for 10 hours. After the mixture was cooled to room temperature, it was filtered to obtain a powder. The powder was then washed with toluene at 40°C, filtered while hot, and vacuum dried to obtain the MyL-1 compound. Infrared and nuclear magnetic resonance (NMR) detection results showed that the MyL-1 compound had the structure shown in formula (1), with R1 and R2 both being C0 (single bond).

[0056] Example 3 Preparation of MyL-1 compound

[0057] 10 mmol of 4-[bis[2-(acetoxy)ethyl]amino]benzaldehyde was dissolved in toluene. Subsequently, 5 mmol of the OBO-type BODIPY derivative A-1 was added in two portions and stirred for 10 minutes. Subsequently, 2 mL of tributyl borate and 0.3 mL of n-butylamine were added and the mixture was reacted at 60°C for 11 hours. After the mixture was cooled to room temperature, it was filtered to obtain a powder. The powder was then washed with toluene at 30°C, filtered while hot, and vacuum dried to obtain the MyL-1 compound. Infrared and nuclear magnetic resonance (NMR) detection results showed that the MyL-1 compound had the structure shown in formula (1), with R1 and R2 both being C0 (single bond).

[0058] Example 4 Preparation of MyL-1 Compound

[0059] 12.5 mmol of 4-[bis[2-(acetoxy)ethyl]amino]benzaldehyde was dissolved in toluene, and then 5 mmol of the OBO-type BODIPY derivative A-2 was added in two portions, stirred for 10 minutes, and then 5 mL of tributyl borate and 0.4 mL of n-butylamine were added. The mixture was reacted at 60°C for 11 hours. After the mixture was cooled to room temperature, it was filtered to obtain a powder. The powder was then washed with toluene at 30°C, filtered while hot, and vacuum dried to obtain the MyL-1 compound. Infrared and nuclear magnetic resonance (NMR) detection results showed that the MyL-1 compound had the structure shown in formula (1), with R1 and R2 both being C0 (single bond).

[0060] Example 5 Preparation of MyL-1 compound

[0061] 11.5 mmol of 4-[bis[2-(acetoxy)ethyl]amino]benzaldehyde was dissolved in toluene. Subsequently, 5 mmol of the OBO-type BODIPY derivative A-3 was added in two portions and stirred for 10 minutes. Subsequently, 1 mL of tributyl borate and 0.2 mL of n-butylamine were added and the mixture was reacted at 60°C for 11 hours. After the mixture was cooled to room temperature, it was filtered to obtain a powder. The powder was then washed with toluene at 30°C, filtered while hot, and vacuum dried to obtain the MyL-1 compound. IR and NMR analysis showed that the MyL-1 compound had the structure shown in formula (1), with R1 and R2 both being C0 (single bond).

[0062] Comparative Example

[0063] Commercial probe FluoroMyelin Green™.

[0064] Test Example 1 Testing the photostability of MyL-1 compounds

[0065] Brain sections were stained with the MyL-1 compounds prepared in Examples 1-5 and the commercial probe FluoroMyelin Green™. The sections were then exposed to continuous confocal laser and depletion laser irradiation for more than 100 scans. The results are shown in Table 1. The fluorescence intensity of the MyL-1 compounds remained relatively stable after intensive exposure. The MyL-1 compound prepared in Example 1 exhibited the best photostability, retaining over 95% and 80% of the signal under confocal and STED depletion conditions, respectively. In contrast, the fluorescence intensity of the commercial probe FluoroMyelin Green™ decreased dramatically, particularly under STED laser irradiation. This demonstrates the strong photostability of the MyL-1 compound.

[0066] Table 1

[0067] Test Example 2 Testing the Sensitivity and Selectivity of MyL-1 Compound to Sphingomyelin

[0068] (1) Fluorescence response experiment: 5 μM of MyL-1 prepared in Examples 1-5 was dissolved in phosphate buffer, and bovine serum albumin, glutamic acid, γ-aminobutyric acid, choline chloride, and acetylcholine chloride at the same molar concentration were added dropwise, and the changes in fluorescence intensity before and after the addition were detected. The results showed that compared with bovine serum albumin, glutamic acid, γ-aminobutyric acid, choline chloride, and acetylcholine chloride, the MyL-1 compounds obtained in the above examples had a significant fluorescence emission enhancement effect on sphingomyelin (sphingomyelin is considered to be the main component of myelin sheath), indicating that the MyL-1 compound can specifically bind to myelin sheath. The results of the MyL-1 compound obtained in Example 1 are shown in Figure 2.

[0069] (2) Titration experiment: 5 μM MyL-1 prepared in Examples 1-5 was dissolved in phosphate buffer, and sphingomyelin (0 μg / ml-0.8 μg / ml) with gradually increasing molar concentrations was added dropwise to detect changes in the fluorescence intensity of the system. The results showed that when the concentration of sphingomyelin increased from 0 to 0.8 μg / mL, the fluorescence enhancement (compared to the MyL-1 solution without sphingomyelin) detected by the MyL-1 compounds obtained in the above examples could reach 14-18 times. The titration experiment further confirmed the specificity and selectivity of the MyL-1 compound for sphingomyelin. The titration experiment results of the MyL-1 compound obtained in Example 1 are shown in Figure 3.

[0070] (3) Molecular docking binding energy experiment: Sphingomyelin lipids are unsaturated and have unequal sn-1 and sn-2 chains, i.e., 16:1 and 18:0 fatty acids as hydrophobic tails. Using the CHARMM force field, the bilayer model was saved in a rectangular box containing 64 lipids (32 per lobe), resulting in a binary system with a hydration number of 95 water molecules / lipid. MD simulations were performed using a standard dynamic cascade protocol, where the system used a 1000-step energy minimization using the steepest descent algorithm, followed by a five-step equilibrium run in the NP (pressure) T set consisting of a constant number of atoms, pressure, and temperature. The production run of the NPT system took at least 10 ns at 300 k and 1 bar. The results of the modeled system provide insights into the phase and structure of lipids in the bilayer. The results obtained confirmed the specificity and selectivity of the MyL-1 compounds obtained in the above examples for sphingomyelin. Among them, the molecular docking binding energy experiment results of the MyL-1 compound obtained in Example 1 are shown in Figure 4.

[0071] Test Example 3: Testing the targeting of the MyL-1 compound to the myelin sheath.

[0072] Brain slices were incubated with the MyL-1 compounds prepared in Examples 1-5 for 30 minutes, followed by immunofluorescence labeling to highlight the neuronal cytoskeleton (tubulin), neuronal synapses (microtubule-associated protein 2), neuronal nuclei (neuronal nuclear-associated protein), astrocytes (glial fibrillary acidic protein), and brain capillary endothelium (labeled with lectin). The results showed that the MyL-1 compounds obtained in the above examples had the highest Pearson correlation coefficients with myelin (calculated by fluorescence colocalization correlation coefficients after confocal dual-channel imaging and channel separation using Image J software). The Pearson correlation coefficients between the MyL-1 compounds and the neuronal cytoskeleton, neuronal synapses, neuronal nuclei, astrocytes (and brain capillary endothelium) were all less than 0, indicating that there was little overlap between the MyL-1 compounds and the other substances listed above, except for myelin, demonstrating that the MyL-1 compounds can specifically label only neuronal myelin components without interference from other substances. The results for the MyL-1 compound obtained in Example 1 are shown in Figure 5.

[0073] Fluorescence colocalization experiments (simultaneously labeling the same tissue section with two probes and calculating the correlation between the overlapping regions, i.e., the Pearson correlation coefficient) showed that the MyL-1 compounds obtained in the above examples all exhibited strong colocalization with the commercial sphingomyelin probe FluoroMyelin Green™, further demonstrating the targeting of the MyL-1 compounds to the myelin sheath. The results for the MyL-1 compound obtained in Example 1 are shown in Figure 6 .

[0074] These results indicate that the MyL-1 compound targets axonal myelin sheaths in the brain parenchyma. Furthermore, although the FluoroMyelin Green™ probe is commercially available, its chemical structure is unknown, and its use in super-resolution nanoscopy is uncertain. As an optical probe, the MyL-1 compound can effectively and accurately label myelin sheaths using red light emission (emission wavelength = 700 nm). This opens the possibility of using the MyL-1 compound to construct myelin ultrastructure using stimulated emission depletion lasers (depletion wavelengths = 660 / 775 nm).

[0075] Test Example 4 Visualization Application of MyL-1 Compound

[0076] 5 μM of the MyL-1 compounds prepared in Examples 1-5 were dissolved in phosphate buffer and added dropwise to the surface of a slice at room temperature for 30 minutes. The slices were frozen sections of mouse brain (20 μm thick) and stained with the commercially available probe FluoroMyelin Green™ at the same scale. The specific staining steps were performed according to the manufacturer's instructions. Preliminary imaging of the neuron-rich region of the corpus callosum under a conventional confocal microscope demonstrated that strong fiber patterns in both parallel and perpendicular directions were clearly observed using the MyL-1 compounds prepared in Examples 1-5, whereas this clarity was not achieved using the FluoroMyelin Green™ probe at the same scale. The fiber pattern of the MyL-1 compound prepared in Example 1 under confocal microscopy is shown in Figure 7 . Corresponding depth-encoded 3D stimulated emission depletion (SED) micrographs were then captured (thickness = 15 μm, 89 mouse brain sections from three independent experiments). The results demonstrated that individual myelin tubular structures could be successfully visualized in 3D using the MyL-1 compounds obtained in Examples 1 to 5, whereas 3D visualization of myelin tubular structures could not be achieved using the FluoroMyelin Green™ probe at the same scale. A three-dimensional image of myelin structure under a 3D stimulated emission depletion (SED) microscope using the MyL-1 compound obtained in Example 1 is shown in FIG8 .

[0077] The above results indicate that the MyL-1 compound has good spatial resolution and can achieve three-dimensional imaging of myelin structure under super-resolution microscopy.

[0078] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention.

Claims

1. A MyL-1 compound for myelin labeling in the central nervous system, characterized in that, The MyL-1 compound has the structure shown in formula (1); In formula (1), R1 and R2 are each independently an alkylene group having 0 to 4 carbon atoms.

2. A method for preparing the MyL-1 compound for myelin labeling in the central nervous system, characterized in that, The preparation method includes subjecting 4-[bis[2-(acetyloxy)ethyl]amino]benzaldehyde having the structure shown in formula (2) and an O-B-O type BODIPY derivative having the structure shown in formula (3) to a condensation reaction in the presence of a catalyst to obtain the MyL-1 compound; In formula (3), R3 and R4 are each independently an alkyl group having 1 to 5 carbon atoms.

3. The preparation method of the MyL-1 compound according to claim 2, characterized in that, The dosage ratio of the 4-[bis[2-(acetoxy)ethyl]amino]benzaldehyde, the O-B-O type BODIPY derivative and the catalyst is (2 - 2.5) mol: 1 mol: (40 - 80) mL.

4. The preparation method of the MyL-1 compound according to claim 2, characterized in that, The temperature of the condensation reaction is 60 - 80 °C.

5. The preparation method of the MyL-1 compound according to claim 2, characterized in that, The time of the condensation reaction is 10 - 12 h.

6. The preparation method of the MyL-1 compound according to claim 2, characterized in that, The O-B-O type BODIPY derivative is obtained by reacting an alkyldiketone compound having the structure shown in formula (4) with boron trifluoride diethyl etherate; For formula (4), R3 and R4 are each independently an alkyl group having 1 to 5 carbon atoms.

7. The method for preparing the MyL-1 compound according to claim 6, wherein The molar ratio of the alkyl diketone compound to boron trifluoride diethyl ether is 1: (1.1 - 1.5).

8. The preparation method of the MyL-1 compound according to claim 6, characterized in that, The reaction temperature is 50 - 70 °C.

9. The method for preparing the MyL-1 compound according to claim 6, wherein, The reaction time is 5 - 7 h.

10. The preparation method of the MyL-1 compound according to claim 2, characterized in that, The condensation reaction is carried out in the presence of a dehydrating agent.

11. The preparation method of the MyL-1 compound according to claim 2, characterized in that, The addition amount of the dehydrating agent is 1 - 5 mL.

12. The method for preparing the MyL-1 compound according to claim 2, wherein The dehydrating agent is selected from at least one of tributyl borate, triethyl borate and trimethyl borate.

13. The preparation method of the MyL-1 compound according to claim 2, characterized in that, The catalyst is selected from at least one of n-butylamine, di-n-butylamine and triethylamine.

14. The MyL-1 compound for myelin labeling in the central nervous system prepared by the method according to claim 2.

15. Use of the MyL-1 compound according to claim 1 in bioimaging.

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