CN108409763B - 3, 5-dibenzoimidazolyl-8-p-cyanophenyl fluoroboron fluorescent derivative and preparation method and application thereof - Google Patents

Abstract

The invention provides a 3, 5-dibenzoimidazolyl-8-p-cyanophenyl fluoroboron fluorescent derivative, belonging to the technical field of fluoroboron fluorescent derivatives. The fluoboron fluorescent derivative has a structure shown in the following formula I:

Description

A kind of 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoroboron fluorescent derivatives and its Preparation method and application

technical field

The invention belongs to the technical field of fluoroboron fluorescent derivatives, in particular to a 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoroboron fluorescent derivative and a preparation method and application thereof.

Background technique

The endoplasmic reticulum is a very important multifunctional organelle in eukaryotic cells. The synthesis, folding, modification of intracellular proteins, and the synthesis of lipids and sterols are carried out in the endoplasmic reticulum. While completing these basic physiological functions, the endoplasmic reticulum has become a hub platform for coordinating signal transduction by virtue of its huge membrane structure, maintaining the stability of the intracellular environment. When genetic or environmental damage causes endoplasmic reticulum stress, excessive or prolonged endoplasmic reticulum stress can cause cell apoptosis, thereby triggering a series of diseases [see: J.E.Vance, Traffic, 2015, 16, 1. ], the specificity of tracking the morphology and distribution of the endoplasmic reticulum in cells is conducive to in-depth understanding and research of many related physiological activities [see: Z.Yang, Y.He, J.H.Lee, W.-S.Chae, W.X.Ren , J.H. Lee, C. Kang and J.S. Kim, Chem. Commun., 2014, 50, 11672.].

In recent years, there have been some reports on targeting reagents for labeling the endoplasmic reticulum, but the mechanism of specific targeting and localization of markers is not very clear. We need more research to design reliable endoplasmic reticulum-labeled targeting reagents. Currently, it is commonly used to combine targeting groups with fluorophores to construct novel endoplasmic reticulum targeting reagents [see: W. Xu, Z . Zeng, J.-H. Jiang, Y.-T. Chang and L. Yuan, Angew. Chem., Int. Ed. 2016, 55, 13658].

Among many fluorescent dyes, fluoroboron complexed dipyrrolemethane fluorescent dyes, also known as fluoroboron fluorescent dyes, have high molar extinction coefficient, high fluorescence quantum yield, stable spectral properties, high photothermal and chemical stability, Due to the advantages of small molecular weight and low cytotoxicity, it has been widely used as fluorescent probes for biomolecules, ions, and fluorescent reagents for organelle imaging [see: (a) S.Arai, S.-C.Lee, D.Zhai , M.Suzuki and Chang,YTSci.Rep.2014,4,6701;(b)X.Kong,F.Su,L.Zhang,J.Yaron,F.Lee,Z.Shi,Y.Tian and Meldrum, DR Angew. Chem., Int. Ed. 2015, 54, 12053; (c) L. Yang, Y.-J.Ji, J.-F.Yin, Y.Wu, H.Fan, Y.Zhang and G. -C. Kuang, Soft Matter, 2016, 12, 8581.]. There are many labeling molecules based on fluoroboron fluorescent scaffolds that have been widely used in the market as standard labeling reagents for organelles, such as LysoTracker ^TM Red, LysoTracker ^TM Green, ER-Tracker ^TM Red and ER-Tracker ^TM Green [see: I. Johnson, MTZ Spence, The Molecular Probes Handbook, A Guide to Fluorescent Probes and Labeling Technologies, 11th Ed.; Molecular Probes: Eugene, OR, 2010.]. However, these common commercially available ER targeting reagents are complex in structure, inconvenient to synthesize and expensive.

Therefore, to provide a fluorescent molecule for endoplasmic reticulum labeling, which is simple in structure, simple in synthesis, and low in production cost, has become an urgent problem to be solved by those skilled in the art.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a fluoroboron-fluorescent derivative small molecule that can be used for endoplasmic reticulum labeling, and the fluoroboron-fluorescent derivative of the present invention can be used for endoplasmic reticulum fluorescent labeling, which can effectively solve the internal problems in the prior art. Mass reticulum targeting reagents are complex in structure, inconvenient to synthesize and expensive.

The present invention also provides a preparation method and application of the fluoroboron fluorescent derivatives.

The object of the present invention is achieved through the following technical solutions:

A 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoroboron fluorescent derivative, having the structure shown in the following formula I:

Wherein: R ₁ , R ₂ , R ₃ are one or both of hydrogen, deuterium, alkyl, alkoxy, carbonyl, ester, halogen, substituted aryl or substituted heteroaryl. Further, the carbon chain of the alkyl group, alkoxy group, ester group or carbonyl group is a straight chain, branched chain or cyclic chain having 0 to 40 carbon atoms.

Further, the substituent groups in the substituted aryl group and the substituted heteroaryl group are one or more of alkyl groups, alkoxy groups or carbonyl groups. Further, the carbon chain of the alkyl group, alkoxy group or carbonyl group is a straight chain, branched chain or cyclic chain with 0-40 carbon atoms.

As a specific embodiment of a 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoroboron fluorescent derivative according to the present invention, it has the structure shown in the following formula II:

A preparation method of 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoroboron fluorescent derivatives, comprising:

1) Mix 8-p-cyanophenyl fluoroboron with benzimidazole derivatives, oxidant and solvent, and then react under anhydrous and oxygen-free conditions. The reaction formula is as follows:

2) After the reaction is completed, cool to room temperature, remove the solvent, add dichloromethane to dissolve the reaction system, filter through celite, wash with dichloromethane, combine the filtrates, remove the solvent under reduced pressure, and use a silica gel column for the residue. The compound of formula I can be obtained by chromatographic separation and purification and vacuum drying.

Further, in the above-mentioned step 1), the anhydrous and oxygen-free conditions can be protected by an inert gas, and further preferably, the reaction can be performed under a nitrogen atmosphere.

The synthetic route used in the preparation method of the present invention is a C-H/N-H direct oxidative coupling reaction, and compared with the traditional fluoroboron fluorescensing preparation technology, the relatively lengthy organic synthesis steps are shortened, and the pre-activation of the substrate is avoided. The tedious process improves the compatibility of the reaction and increases the overall yield of the synthesis reaction.

As a specific example of the preparation method of a 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoroboron fluorescent derivative according to the present invention, the oxidant is copper acetate monohydrate, acetic acid Copper, copper chloride, copper bromide, ketone trifluoroacetate, copper(Ⅱ) trifluoromethanesulfonate, copper acetylacetonate, silver carbonate, silver oxide, silver acetate, silver nitrate, silver hexafluoroantimonate, oxygen, acetic acid One or more of iodobenzene, benzoquinone, dichlorobenzoquinone, sodium peroxodisulfate, ammonium peroxodisulfate, potassium peroxodisulfate, and di-tert-butyl peroxide.

As a specific embodiment of the preparation method of a 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoroboron fluorescent derivative described in the present invention, the solvent is methanol, ethanol, tetrahydrofuran, Dichloromethane, chloroform, diethyl ether, dimethyl sulfoxide, benzene, o-dichlorobenzene, chlorobenzene, toluene, xylene, mesitylene, cyclohexane, petroleum ether, tert-amyl alcohol, 1,4- One or more of dioxane, 1,2-dichloroethane, N,N-dimethylformamide, and N,N-dimethylacetamide.

As a specific embodiment of the preparation method of a 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoroboron fluorescent derivative according to the present invention, the 8-p-cyanophenyl fluoride The reaction concentration of boron fluorescence is 0.0001～10mol/L. More preferably, it is 0.1-8 mol/L, 0.5-5 mol/L, 1-3 mol/L.

As a specific embodiment of the preparation method of a 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoroboron fluorescent derivative according to the present invention, the 8-p-cyanophenyl fluoride Boron fluoride, benzimidazole derivatives, the molar ratio of oxidant is 1:(0.01～50):(0.01～100). More preferably, it is 1:(0.1-40):(10-80), 1:(5-30):(20-60).

As a specific embodiment of the preparation method of a 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoroboron fluorescent derivative according to the present invention, the reaction temperature of the step 1) is- 40-160°C, more preferably 20-100°C, 40-80°C; time is 0.1-720h, more preferably 10-30h.

The present invention also provides the application of the 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoroboron fluorescent derivative, which is used in the specific fluorescence imaging and fluorescent labeling of endoplasmic reticulum. application.

As a specific embodiment of the application of a 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoroboron fluorescent derivative according to the present invention, the following steps are included:

Step 1: Cultivate cells in culture medium;

Step 2: Remove the culture medium from the cultured cells, add a buffer of 3,5-dibenzimidazolyl-8-p-cyanophenylfluoroboron-fluorine derivatives, and culture;

Step 3: After the incubation in Step 2, the culture glass-bottom dish was imaged by a fluorescence confocal microscope.

As a specific example of the application of a 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoroboron fluorescent derivative of the present invention, the cells are HepG2 cells.

As a specific example of the application of a 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoroboron fluorescent derivative according to the present invention, the culture medium is a medium containing 10% fetal bovine serum. DMEM(H) medium.

As a specific example of the application of a 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoroboron fluorescent derivative of the present invention, the 3,5-dibenzimidazolyl- The buffer concentration of 8-p-cyanophenyl fluoroboron fluoro derivatives is 2.5 μM phosphate buffer.

As a specific example of the application of a 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoroboron fluorescent derivative according to the present invention, the culture condition in step 1 is to culture at 37°C for 24 Hour.

As a specific embodiment of the application of a 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoroboron fluorescent derivative according to the present invention, the following steps are included:

HepG2 cells were cultured at 37°C for 24 hours in DMEM(H) medium containing 10% fetal bovine serum with 5% CO ₂ ; the medium was removed and 2.5 μM compound 3,5-dibenzimidazole was added basal-8-p-cyanophenyl fluoroboron phosphate buffer, incubate for 30 minutes; after the incubation, take out the culture glass-bottom dish, wash it with phosphate buffer Imaged by fluorescence confocal microscopy.

Compared with the prior art, the present invention has the following beneficial effects:

Compared with the existing commercially available endoplasmic reticulum fluorescent labeling reagents, the synthetic route of the 3,5-dibenzimidazolyl-8-p-cyanophenylfluoroboron fluorescent derivatives of the present invention is more concise, efficient and environmentally friendly , the product is cheap and easy to obtain in large quantities. Specifically:

1. The synthetic route used in the present invention is a direct oxidative coupling reaction of C-H/N-H, which shortens the lengthy organic synthesis steps and avoids the pre-activation of the substrate compared with the traditional preparation technology of fluoroboron fluorescensing. The tedious process improves the compatibility of the reaction and increases the overall yield of the synthesis reaction.

2. Compared with the commercially available endoplasmic reticulum labeling reagents ER-Tracker Red and ER-Tracker Green, the compound of the present invention is simple in synthesis and low in price. The price of ER-Tracker Red and ER-Tracker Green is as high as 4863 yuan/100μg (Thermo Fisher Scientific Company), and our products are relatively much cheaper. Among the synthetic raw materials, even the most expensive AgOAc is used as an oxidant. It is only 289 yuan/25g (Annagy Company), and other synthetic raw materials are cheap and easily available compounds in the market. The price of the fluoroboron-fluorescent derivatives in this application is about 3000-5000 yuan/1g. At the same time, under the reaction conditions of the present invention, the yield can reach more than 60%. Therefore, the cost of using the fluoroboron fluorescent derivatives of the present invention as fluorescent labeling of endoplasmic reticulum will be much lower than that of commercially available labeling reagents.

Description of drawings

Figure 1 is the general structural formula of 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoroboron fluorescent derivatives.

Fig. 2 is the H spectrum of 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoride boron fluoride.

Figure 3 is the C spectrum of 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoride boron fluoride.

Figure 4 shows the UV-Vis absorption spectrum and the fluorescence emission spectrum of 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoroboron fluorescence.

Figure 5 is a cell imaging image of 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoroboron fluorescently labelled endoplasmic reticulum.

Figure 6 shows the results of the CCK8 cytotoxicity assay of 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoroboron in HepG2 cells.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

In the examples of the present invention, HepG2 cell line was purchased from ATCC (American Type Culture Collection) company, 10% fetal bovine serum was purchased from Hyclone company, and DMEM(H) (Dulbecco's modifiedessential medium) medium was purchased from Gibco, USA. The endoplasmic reticulum dye ER-Tracker ^™ Green was purchased from Thermo Fisher Scientific.

Example 1

Synthesis of 3,5-Dibenzimidazolyl-8-p-cyanophenylfluoroboron

8-p-Cyanophenyl fluoroboron (14.6 mg, 0.05 mmol), benzimidazole (23.6 mg, 0.20 mmol), AgOAc (33.4 mg, 4.0 equiv), dimethyl sulfoxide (1.0 mL) were added to the reaction The tube was heated to 80 ° C after stirring evenly under nitrogen conditions, and the reaction was carried out for 12 hours; the specific reaction formula was as follows:

After the reaction was completed, the reaction tube was cooled to room temperature, the solvent was removed, and 10 mL of dichloromethane was added to dissolve the reaction system, then filtered through celite and washed with 10 to 20 mL of dichloromethane, the filtrates were combined, and the solvent was removed under reduced pressure, The residue was separated and purified by silica gel column chromatography (dichloromethane/petroleum ether/ethyl acetate=2:2:1, v/v/v), and the target product 3,5-dibenzimidazole was obtained after vacuum drying. yl-8-p-cyanophenyl fluoroboron fluoride 15.7 mg, yield 60%.

The H spectrum and C spectrum of the dibenzimidazolyl-8-p-cyanophenyl fluoride boron NMR spectrum of the product of this example are shown in Figure 2 and Figure 3, respectively, and the structural data is characterized as follows:

¹ H NMR (400MHz, CDCl3) δ=6.81 (d, J=4.4Hz, 2H), 7.02 (d, J=4.8Hz, 2H), 7.32-7.39 (m, 4H), 7.46-7.48 (m, 2H) ), 7.78(d, J＝8.4Hz, 2H), 7.87(dd, J＝6.0Hz, 2.4Hz, 2H), 7.93(d, J＝8.4Hz, 2H), 8.62(s, 2H). ¹³ C NMR (100MHz, CDCl3)δ=111.2, 114.97, 115.03, 117.9, 121.3, 124.2, 124.7, 131.3, 131.9, 132.55, 132.64, 133.7, 137.3, 142.2, 143.3, 143.9, 147.6. HRMS (ESI ⁺ ): Calculated _C30H19BF2N7 [M ₊ H] ⁺ : _526.1758 , found _526.1761 .

Example 2

The ultraviolet-visible-near-infrared absorption spectrum and fluorescence emission spectrum of the compound 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoroboron prepared in Example 1

Dissolve the compound 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoroboron in dichloromethane to make 1×10 ^{- 5} mol/L, take 2.5mL and put it in a cuvette, UV-Vis-NIR absorption and fluorescence emission spectra were measured.

Figure 4 shows the UV-Vis absorption spectrum and fluorescence emission spectrum of the compound 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoroboron, in which the black solid line represents the UV-Vis absorption spectrum, and the black dotted line represents the fluorescence emission spectrum . It can be seen from Figure 4 that the maximum absorption peak of the absorption spectrum of the compound 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoroboron is located at 561 nm; the maximum absorption peak of the fluorescence emission spectrum is located at 592 nm, and Stokes The St.s shift is 31 nm.

Example 3

Fluorescence confocal confocal imaging of the compound 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoroboron prepared in Example 1 and the commercially available endoplasmic reticulum stain ER-Tracker ^TM Green in HepG2 cells

First, DMEM(H) medium containing 10% fetal bovine serum was bubbled with 5% CO ₂ , and HepG2 cells were cultured at 37° C. for 24 hours. The medium was removed and 2.5 μM of the compound 3,5-dibenzimidazolyl-8-p-cyanophenylfluoroboron was added in phosphate buffer followed by 1 μM of the commercially available endoplasmic reticulum stain ER-Tracker ^™ Green Co-incubate at 37°C for 30 minutes. After the culture is completed, the culture glass bottom dish is taken out, washed with phosphate buffer for 2-3 times, and then the culture glass bottom dish is imaged by a fluorescence confocal microscope.

FIG. 5 is a fluorescence imaging image of compound 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoroboron (excitation wavelength: 553 nm, emission wavelength collection range: 550-650 nm). It can be seen intuitively that the compound 3,5-dibenzimidazole is compared with the fluorescence image of the commercially available endoplasmic reticulum stain ER-Tracker ^TM Green (excitation wavelength: 488nm, emission wavelength collection range: 450-550nm). The distribution of fluoro-8-p-cyanophenyl fluoroboron in cells is basically the same as that of the commercial endoplasmic reticulum stain ER-Tracker ^TM Green, and the corresponding Pearson's coefficient reaches 0.89, indicating that the compound 3,5-dibenzimidazolyl -8-P-Cyanophenyl Fluoroboron Fluorescence has excellent endoplasmic reticulum tracing effect and can specifically label the endoplasmic reticulum in cells.

Example 4

CCK8 cytotoxicity test of the compound 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoroboron prepared in Example 1

HepG2 cells in logarithmic growth phase were seeded in a 96-well culture plate at 3000 cells per well, in DMEM(H) medium containing 10% fetal bovine serum permeated with 5% _CO at 37°C. Incubate overnight. After the cells were completely adhered, different concentrations of the compound 3,5-dibenzimidazolyl-8-p-cyanophenylfluoroboron were added, and three duplicate wells and blank control wells were set up for each concentration group. The cells were cultured for 24 hours after adding the samples, and the cell viability was detected by CCK8 assay.

Figure 6 shows the results of the CCK8 cytotoxicity assay of 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoroboron in HepG2 cells. As shown in Figure 6, the cell viability of the compound 3,5-dibenzimidazolyl-8-p-cyanophenylfluoroboron was very high (over 90%) in the concentration range of 0.25-4 μM. , the survival rate was significantly reduced at 8 μM (the survival rate was less than 60%), indicating that the compound 3,5-dibenzimidazolyl-8-p-cyanophenylfluoroboron was very toxic at our labeling working concentration. small and can be ignored.

Example 5

In the preparation method of Example 1, deuterium, alkyl, alkoxy, carbonyl, ester, halogen, substituted aryl or substituted heteroaryl are respectively used to replace the hydrogen in R ₁ , R ₂ and R ₃ . Other conditions remained unchanged, and a series of 3,5-dibenzimidazolyl-8-p-cyanophenylfluoroboron-fluorescent derivatives capable of specific fluorescence imaging and fluorescent labeling of the endoplasmic reticulum were successfully prepared. Among them, the product prepared in Example 1 had the best effect on endoplasmic reticulum fluorescence imaging and fluorescent labeling.

Example 6

In the preparation method of embodiment 1 or 5, adjust the relevant parameters to carry out a series of experiments:

In step 1), select -40°C, -20°C, 0°C, 20°C, 40°C, 60°C, 100°C, 120°C, 140°C, and 160°C to replace 80°C; the reaction time is controlled within 0.1-720h;

Controlling 8-p-cyanophenyl fluoroboron-fluorescent derivatives and benzimidazole derivatives respectively, the molar ratio of oxidant is 1:(0.01～50):(0.01～100);

With copper acetate monohydrate, copper acetate, copper chloride, copper bromide, ketone trifluoroacetate, copper (II) trifluoromethanesulfonate, copper acetylacetonate, silver carbonate, silver oxide, silver nitrate, silver hexafluoroantimonate , oxygen, iodobenzene acetate, benzoquinone, dichlorodicyanobenzoquinone, sodium peroxodisulfate, ammonium peroxodisulfate, potassium peroxodisulfate, di-tert-butyl peroxide instead of silver acetate;

With methanol, ethanol, tetrahydrofuran, dichloromethane, chloroform, ether, benzene, o-dichlorobenzene, chlorobenzene, toluene, xylene, mesitylene, cyclohexane, petroleum ether, tert-amyl alcohol, 1,4 -Dioxane, 1,2-dichloroethane, N,N-dimethylformamide, N,N-dimethylacetamide instead of dimethylsulfoxide.

Through the screening of experimental parameters, it is found that under the above conditions, 3,5-dibenzimidazolyl-8-p-cyanophenylfluoroboron fluorophores can be successfully prepared that can achieve specific fluorescence imaging and fluorescent labeling of the endoplasmic reticulum. derivative. Among them, the product prepared in Example 1 had the best effect on endoplasmic reticulum fluorescence imaging and fluorescent labeling.

The above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included in the protection of the present invention. within the range.

Claims (2)

1. a 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoroboron, its structural formula is as follows

2. the application of a kind of 3,5-dibenzimidazolyl-8-p-cyanophenyl fluoroboron fluorescence as claimed in claim 1, it is characterized in that, it is in cell endoplasmic reticulum-specific fluorescence development and fluorescence Applications in markers that do not involve the diagnosis and treatment of diseases.

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