Electron donor-double receptor type fluorescent compound as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of organic synthesis, and relates to an electron donor-double receptor type fluorescent compound as well as a preparation method and application thereof, the electron donor-double receptor type fluorescent compound has the following structural formula: # imgabs0 #, R1 is at least one of the following functional groups: # imgabs1 # R2 is H,-CH3,-COOCH2CH3,-COOCH3 or-NO2; x1 is a halogen ion; the preparation method comprises the following steps: # imgabs2: mixing a compound as shown in a formula 2, a compound as shown in a formula 3 and organic alkali, and carrying out a Knoevenagel reaction to obtain the electron donor-double receptor type fluorescent compound. Compared with the prior art, the photosensitizer structure disclosed by the invention can efficiently generate active oxygen and shows an efficient photodynamic killing effect on methicillin-resistant staphylococcus aureus and escherichia coli. Due to the characteristics, the donor-double acceptor pyridinium salt derivative has important application value in the development of novel antibacterial materials.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic synthesis, and relates to an electron donor-dual acceptor (ADA) type fluorescent compound, a preparation method and application thereof, and in particular to an electron donor-dual acceptor type fluorescent compound, a preparation method and application thereof in the preparation of an antibacterial agent. Background Art

[0002] Bacteria, as the largest biological group on earth, play an active role in the food industry (such as fermentation), biotechnology (such as biofuel production), medicine (such as the development of antibiotics and vaccines), and other fields. They have had a profound impact on human society and have also posed a major threat to human health. In recent years, the development of new antibiotics has lagged far behind the development of drug resistance, and traditional antibiotic development channels have almost dried up. Therefore, the development of new strategies and treatments that can effectively combat drug-resistant bacterial infections has become a global research focus.

[0003] Photodynamic therapy (PDT) is a non-invasive and innovative treatment method that has attracted more and more attention from scientific researchers and medical workers. Among the key factors of photodynamic therapy, photosensitizers (PSs) are the most important component. Photodynamic therapy (PDT) uses excitation light of a specific wavelength to activate photosensitizers (PSs) to produce reactive oxygen species (ROS), thereby killing microorganisms or inducing cell apoptosis. Due to its non-contact, convenient, low-risk and broad-spectrum antimicrobial properties, it is widely considered to be a promising method for treating various tumors and bacterial infections. However, due to the limited penetration depth of light into tissues, its effect in treating deep pathological tissues is limited.

[0004] Recent studies have demonstrated that near-infrared (NIR) light exhibits exceptional tissue penetration capabilities while minimizing collateral damage to normal cells, thereby providing significant benefits and driving the advancement of NIR light-excited photosensitizers. Therefore, NIR photosensitizers are an effective tool to enhance the therapeutic depth of photodynamic therapy. Summary of the invention

[0005] The purpose of the present invention is to provide an electron donor-dual acceptor fluorescent compound and its preparation method and application. The photosensitizer structure of the present invention can efficiently generate active oxygen and show efficient photodynamic killing effect on methicillin-resistant Staphylococcus aureus (Gram-positive bacteria) and Escherichia coli (Gram-negative bacteria). These characteristics make the donor-dual acceptor pyridinium salt derivatives have important application value in the development of new antibacterial materials.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] The first aspect of the present invention provides an electron donor-dual acceptor type fluorescent compound having the following structural formula:

[0008]

[0009] Among them, R 1 is at least one of the following functional groups:

[0010]

[0011] R 2 H, -CH 3 、-COOCH 2 CH 3 、-COOCH 3 or-NO 2 ;

[0012] X 1 It is a halogen ion.

[0013] The electron donor-dual acceptor fluorescent compound provided by the present invention uses pyridinium salt as the electron donor group, which provides many advantages for antibacterial applications in the design of fluorescent materials, including enhanced water solubility and bacterial adsorption capacity, excellent photophysical and chemical properties, bacterial responsiveness, photosensitizer activity, and the potential for optimizing performance through structural modification. These characteristics make pyridinium salt derivatives of great value in the development of new antibacterial materials and can regulate the optical properties of target compounds in solution. The compounds of the present invention belong to the ADA type structure, which promotes red-shifted absorption and emission wavelengths by enhancing intramolecular charge transfer (ICT), reduces the singlet-triplet energy gap, and promotes intersystem crossing, thereby activating photodynamic properties.

[0014] Furthermore, R 1 for

[0015] Furthermore, R 2 For-No 2 .

[0016] Furthermore, X 1 is bromide ion and / or iodide ion.

[0017] Furthermore, the compound has the following structural formula:

[0018]

[0019] A second aspect of the present invention provides a method for preparing an electron donor-dual acceptor type fluorescent compound, comprising the following steps:

[0020]

[0021] The compound shown in Formula 2 is mixed with the compound shown in Formula 3 and an organic base, and subjected to a Novegrin reaction to obtain the electron donor-dual acceptor type fluorescent compound.

[0022] Furthermore, the preparation method of the compound as shown in Formula 2 comprises:

[0023]

[0024] A phenol compound as shown in Formula 1 and hexamethylenetetramine (HMTA) are mixed and subjected to a Williamson synthesis reaction.

[0025] Furthermore, in the Williamson synthesis reaction, the reaction conditions include at least one of the following conditions:

[0026] A) the molar ratio of the phenol compound to hexamethylenetetramine is 1:(2.0-2.5);

[0027] B) The reaction temperature is 100-120°C and the reaction time is 20-24h;

[0028] C) The reaction solvent is trifluoroacetic acid (TFA).

[0029] Furthermore, the preparation method of the compound as shown in Formula 3 comprises: reacting 4-methylpyridine with X 1 -R 1 The reaction was heated.

[0030] Furthermore, in the heating reaction, the reaction conditions include at least one of the following conditions:

[0031] A) the 4-methylpyridine and X 1 -R 1 Medium R 1 The molar ratio of the groups is 1:(1-1.5);

[0032] B) The reaction temperature is 80-95°C and the reaction time is 12-24h;

[0033] C) The reaction solvent is acetonitrile (ACN).

[0034] Furthermore, the molar ratio of the compound shown in Formula 2 to the compound shown in Formula 3 is 1:(1.8-2.0); the molar ratio of the compound shown in Formula 2 to the organic base is 1:(2.0-2.5).

[0035] Furthermore, in the Novoweng reaction, the reaction temperature is 80-90°C and the reaction time is 1-3h.

[0036] In some specific embodiments,

[0037]

[0038] The preparation method of the electron donor-dual acceptor type fluorescent compound comprises the following steps:

[0039] S1: Add an organic solvent TFA to a phenol compound and HMTA as shown in Formula 1, and heat to react overnight under a protective atmosphere. After the reaction is completed, add a dilute hydrochloric acid solution and continue to heat to react under a protective atmosphere to obtain a compound as shown in Formula 2 through a Williamson synthesis reaction;

[0040] S2: 4-methylpyridine and X 1 -R 1 , and an organic solvent ACN, and reflux for 24 hours under a protective atmosphere to obtain a compound as shown in Formula 3;

[0041] S3: Mix the compound shown in Formula 2, the compound shown in Formula 3, and the organic base piperidine, and heat them to obtain an electron donor-dual acceptor fluorescent compound through a Brainweaver reaction.

[0042] The third aspect of the present invention provides an application of an electron donor-dual acceptor fluorescent compound, including using the electron donor-dual acceptor fluorescent compound to prepare an antibacterial agent.

[0043] Furthermore, the electron donor-dual acceptor fluorescent compound is used as a photosensitizer for photodynamic therapy, and has a significant photodynamic killing effect on methicillin-resistant Staphylococcus aureus and Escherichia coli.

[0044] The present invention proposes a new type of electron donor-dual acceptor fluorescent molecular compound, and particularly emphasizes its characteristics based on the donor-acceptor structure and its application potential in fluorescence detection technology. This fluorescent molecule has excellent performance, can realize internal charge transfer, form a long π-electron system, and emit fluorescence in the near-infrared region, which is suitable for in vivo imaging. The new photosensitizer (PSs) has a propeller configuration, which effectively replaces the toxic inorganic nanophotosensitive materials, and the helical configuration suppresses the fluorescence quenching phenomenon. By enhancing intramolecular charge transfer (ICT), the red shift of the absorption and emission wavelengths can be promoted, and the energy gap between the singlet and triplet states can be reduced, thereby improving the photodynamic performance. It is particularly noteworthy that this type of compound contains pyridinium salts, which provides it with many advantages in antibacterial applications, such as improved water solubility and bacterial adsorption capacity, excellent photophysical and chemical properties, bacterial responsiveness and photosensitizer activity. In addition, the potential for optimizing performance through structural modification is also obvious.

[0045] Compared with the prior art, the present invention has the following characteristics:

[0046] 1) The present invention uses a simple and efficient method to synthesize ADA-type symmetrical structure compounds by using pyridinium salts and 2-hydroxyisophthalaldehyde and its derivatives through the Novovenge reaction. Such compounds promote red-shifted absorption and emission wavelengths by enhancing intramolecular charge transfer (ICT). These characteristics make pyridinium salt derivatives of great value in the development of new antibacterial materials;

[0047] 2) The present invention finds through active oxygen testing that as the electron-withdrawing ability of the donor group increases, its ability to generate singlet states increases, and its antibacterial effect is the best;

[0048] 3) The present invention provides a class of pyridinium salt cations as electron donor groups, enhanced water solubility and bacterial adsorption capacity, excellent photophysical and chemical properties, bacterial responsiveness, photosensitizer activity, and the potential for optimizing performance through structural modification;

[0049] 4) The compounds provided by the present invention can selectively respond to Gram-negative bacteria and have a certain antibacterial effect on Gram-positive bacteria. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 (A) and Figure 1 (B) is the UV-visible absorption spectra of the fluorescent compounds D01-D12 and D13-D33 prepared in Example 2;

[0051] Figure 2 to Figure 5 These are the changes in absorbance at 412nm of the mixed solution of fluorescent compounds D01, D03, D13, D28 and singlet oxygen scavenger DPBF as a function of illumination time;

[0052] Figure 6 The absorption spectrum of the singlet oxygen scavenger DPBF solution changes with the illumination time;

[0053] Figure 7 The UV-visible absorption spectra of fluorescent compounds D28, DPBF and compound RB show changes in absorbance at 412 nm with illumination time. DETAILED DESCRIPTION

[0054] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0055] The following are more detailed implementation cases, which further illustrate the technical solutions of the present invention and the technical effects that can be obtained.

[0056] In the following examples, unless otherwise specified, raw materials, reagents or processing techniques are all conventional commercial products or conventional processing techniques in the art.

[0057] Example 1: Synthesis of starting compounds

[0058]

[0059] A starting compound A, the preparation method of which comprises:

[0060] 4-Methylpyridine (20 mmol, 1.8626 g) and (3-bromopropyl)trimethylammonium bromide (16 mmol, 1.044 g) were added to the reaction flask, and 10 mL of anhydrous acetonitrile (ACN) was added. 2 Under protection, the reaction temperature was raised to 80°C and refluxed for 24 hours. After the reaction was completed, the mixture was cooled to room temperature and the reaction solution was added dropwise into 20 mL of ethyl acetate solution. The mixture was allowed to stand for half an hour and a large amount of white solid precipitated. The solid was filtered, washed with ethyl acetate several times, and dried to obtain compound A (white solid, 5.45 g, yield: 76.96%).

[0061] The H NMR spectrum is 1 H NMR(500MHz,Deuterium Oxide)δ8.62(d,J=6.8Hz,2H),7.85(d,J=6.3Hz,2H),4.58(t,J=7.6Hz,2H),3.59–3.22(m,2H),3.09(s,9H),2.59(s,3H),2.55–2.26(m,2H).

[0062] In this example, the following compounds were synthesized by replacing (3-bromopropyl)trimethylammonium bromide with the corresponding compound in the reaction equation in an equimolar amount using the same method (unless otherwise specified, the remaining preparation steps and conditions of the following compounds are the same as those of compound A):

[0063] Synthesis of starting compound B

[0064]

[0065] The H NMR spectrum is 1H NMR(500MHz,DMSO-d6)δ9.06(d,J=6.7Hz,2H),8.03(d,J=6.9Hz,2H),4.63(t,J=7.3Hz,2H),3.35(dd,J=8.1,4 .1Hz,2H),3.09(s,9H),2.62(s,3H),2.02–1.92(m,2H),1.75(dq,J=12.1,6.4,4.9Hz,2H),1.33–1.22(m,2H).

[0066] Synthesis of starting compound C

[0067]

[0068] The H NMR spectrum is 1 H NMR(500MHz,DMSO-d6)δ9.06(d,J=6.8Hz,2H),8.02(d,J=6.2Hz,2H),4.60(t,J=7.4Hz,2H),3.38–3.32(m,2H), 3.09(s,9H),2.62(s,3H),1.93(t,J=7.4Hz,2H),1.69(td,J=9.4,8.0,4.3Hz,2H),1.32(dd,J=6.9,3.5Hz,4H).

[0069] Synthesis of starting compound D

[0070]

[0071] The H NMR spectrum is 1 H NMR(500MHz,DMSO-d6)δ8.92(d,J=6.8Hz,2H),7.98(d,J=7.0Hz,2H),4.61(t ,J=7.1Hz,2H),3.44(td,J=5.9,4.8Hz,2H),2.61(s,3H),2.10–1.98(m,2H).

[0072] Synthesis of starting compound F

[0073]

[0074] 4-Methylpyridine (5.0mmol, 0.49ml) and 1,3-dibromopropane (20mmol, 2.04mL) were added to the reaction flask, and then 10mL of anhydrous acetonitrile was added, and the reaction mixture was refluxed for 4h. After the reaction was completed, the reaction solution was cooled to room temperature, and the solvent was removed by vacuum evaporation. Ethyl acetate was added to the remaining liquid to precipitate, and then the precipitate was filtered, washed with ethyl acetate several times, and dried to obtain product E (white solid, yield 92.46%).

[0075] Compound E (2.05 mmol, 604.79 mg), NaN 3 (5.13mmol, 333.18mg) was added to the reaction bottle, and then 10mL of acetonitrile was added and refluxed for 16h. After the reaction was completed, the reaction solution was cooled to room temperature, the solution was dried by spin drying, DCM was added for washing, filtered and dried again, and the solvent was evaporated to obtain compound F (0.945g, yield: 89.66%).

[0076] The H NMR spectrum of the starting compound F is 1 H NMR (500MHz, DMSO-d6) δ9.04(d,J=6.7Hz,2H),8.03(d,J=7.0Hz,2H),4.67(t,J=7.2Hz,2H),3.48(t,J=6.6Hz,2H),2.62(s,3H),2.23–2.14(m,2H).

[0077] Synthesis of starting compound 11

[0078]

[0079] The hydrogen nuclear magnetic resonance spectrum of the starting compound 11 is 1H NMR (500 MHz, DMSO-d6) δ = 8.97 (2H, d, J = 6.8 Hz), 8.04 (2H, d, J = 6.8), 4.7 (2H, t, J = 6.8 Hz), 3.06 (1H, t, J = 2.4 Hz), 2.95 (2H, dt, J = 6.8, 2.4 Hz), 2.62 (3H, s).

[0080] Synthesis of starting compound 13

[0081]

[0082] The compound 3-methylthiopropanol (5.8 mmol, 615.90 mg) was dissolved in anhydrous ether. Under nitrogen protection, the mixed solution was cooled to 0°C and PBr was slowly added. 3 (2.3 mmol, 622.59 mg) for 30 min, the mixture was warmed to room temperature and stirred overnight, the reaction mixture was cooled to 0 °C, 10 mL of water was slowly added, the organic phase was separated, and saturated NaHCO 3 The product was washed with brine, dried over anhydrous sodium sulfate, and then the organic phase was spin-dried. The obtained product was directly reacted with 4-methylpyridine in the next step.

[0083] The H NMR spectrum of the starting compound 13 is 1H NMR(500MHz,DMSO-d6)δ9.01(d,J=6.8Hz,2H),8.01(d,J=6.2Hz,2H),4.64(t,J= 7.3Hz,2H),2.62(s,3H),2.57–2.42(m,2H),2.20(p,J=7.3Hz,2H),2.06(s,3H).

[0084] Synthesis of starting compound K

[0085]

[0086] The H NMR spectrum is 1 H NMR(500MHz,Chloroform-d)δ9.34(d,J=6.8Hz,2H),7.80(d,J=8.1Hz,2H),7.76 (d,J=6.3Hz,2H),7.60(d,J=8.1Hz,2H),6.24(s,2H),2.59(s,3H),1.32(s,12H).

[0087] Example 2: Synthesis of fluorescent compounds

[0088]

[0089] The synthesis of fluorescent compound D01 includes the following steps:

[0090] S1: Phenol (28.68mmol, 2.6991g), hexamethylenetetramine (HMTA, 57.37mmol, 8.04g) were added to a reaction bottle, 30mL of trifluoroacetic acid (TFA) was added, the temperature was raised to 120°C, the reaction was continued for 20h, after the reaction was completed, the oil bath temperature was lowered to 100°C, 50mL (3M) HCl solution was quickly added, reflux was continued for 1h, and then slowly cooled to room temperature. A large amount of yellow precipitate appeared, the precipitate was filtered, washed with distilled water several times, and dried to obtain intermediate compound a (light yellow solid powder, 2.5803g, yield: 59.93%).

[0091] S2: 4-methylpyridine (20 mmol, 1.8626 g) and (3-bromopropyl)trimethylammonium bromide (16 mmol, 1.044 g) were added to the reaction flask, and 10 mL of anhydrous acetonitrile was added. 2 Under protection, the reaction temperature was raised to 80°C and refluxed for 24 hours. After the reaction was completed, the mixture was cooled to room temperature and the reaction solution was added dropwise into 20 mL of ethyl acetate solution. The mixture was allowed to stand for half an hour and a large amount of white solid precipitated. The solid was filtered, washed with ethyl acetate several times, and dried to obtain the starting compound A (white solid, 5.45 g, yield: 76.96%).

[0092] S3: Add compound a (0.45 mmol, 67.56 mg) and starting compound A (0.9 mmol, 318.72 mg) to a reaction flask, add 3 mL of anhydrous ethanol, N 2 Piperidine (0.9 mmol, 90 μL) was added under protection, the reaction temperature was raised to 80°C for 1 h, and after the reaction was completed, the reaction solution was cooled to room temperature, and then the reaction solution was added dropwise to ethyl acetate and allowed to stand for 1 h. The precipitate was then filtered, washed with ethyl acetate several times, and the ethyl acetate was removed by an oil pump (dark purple solid, 172.80 mg, yield: 46.69%).

[0093] The H NMR spectrum is 1 H NMR(500MHz,DMSO-d6)δ8.75(d,J=6.6Hz,4H),8.11(d,J=15.7Hz,2H),8.04(d,J=6.5Hz,4H),7.8 7(d,J=15.7Hz,2H),7.46(d,J=7.6Hz,2H),4.50(t,J=7.4Hz,4H),3.44(m,4H),2.47–2.37(m,4H).

[0094] The carbon NMR spectrum is 13 C NMR (126MHz, DMSO-d6) δ156.05,155.45,144.04,142.66,126.91,126.15,122.86,119.92,119.72,62.34,56.39,44.15,24.69.

[0095] High-resolution mass spectrum: HRMS (ESI) m / z [M+H] + calcd for C40H32BF2N5S4 +, theoretical value: 759.1716; measured value: 759.1665.

[0096] In this example, the following compounds were synthesized by replacing the starting compound A with an equal molar amount of the corresponding starting compound in Table 1 and replacing the corresponding intermediate compound a with an equal molar amount of the corresponding intermediate compound in Table 1 (unless otherwise specified, the remaining preparation steps and conditions of the following compounds are the same as those of the preparation of the fluorescent compound D01): Synthesis of Fluorescent Compound D02

[0097]

[0098] The H NMR spectrum is 1H NMR (500MHz, DMSO-d6) δ8.77(d,J=6.4Hz,4H),8.10(d,J=15.7Hz,2H),8.05(d,J=6.5Hz,4H),7.82(d,J=15.7Hz ,2H),7.36(s,2H),4.51(t,J=7.3Hz,4H),3.45(q,J=7.0Hz,4H),3.12(s,18H),2.49–2.38(m,4H),2.20(s,3H).

[0099] Synthesis of fluorescent compound D03

[0100]

[0101] The H NMR spectrum is 1 H NMR(500MHz,DMSO-d6)δ8.81(d,J=6.8Hz,4H),8.11(d,J=6.8Hz,2H),8.05(d,J= 15.6Hz,4H),7.97(s,2H),3.77(s,4H),3.50–3.41(m,3H),2.44(p,J=7.7Hz,4H).

[0102] The carbon NMR spectrum is 13 C NMR (126MHz, DMSO-d6) δ178.16,166.86,156.33,143.82,143.36,137.06,125.74,122.61,119.27,109.62,62.30,56.23,52.94,51.53,24.65.

[0103] High resolution mass spectrometry: HRMS (ESI) m / z [M / 4] 4+ Calcd for C34H48N4O34+, theoretical value: 140.0926; measured value: 140.0926.

[0104] Synthesis of fluorescent compound D04

[0105]

[0106] The H NMR spectrum is 1H NMR(500MHz,DMSO-d6)δ8.07(d,J=6.7Hz,4H),8.06–8.00(m,4H),7.98(d,J=14.0Hz,4H),4.49(t,J=7.3H z,2H),3.38–3.30(m,4H),3.09(s,18H),1.95(p,J=7.4Hz,4H),1.81–1.72(m,4H),1.30(p,J=7.1Hz,4H).

[0107] The carbon NMR spectrum is 13 C NMR (126MHz, DMSO-d6) δ177.99,166.89,156.00,143.72,143.03,136.76,125. 70,122.61,119.22,109.61,65.33,58.87,49.25,44.16,30.35,22.62,22.00.

[0108] High-resolution mass spectrum: HRMS (ESI) m / z [M / 4] 4+calcd for C38H56N4O34+, theoretical value: 154.1082; measured value: 154.1080.

[0109] Synthesis of fluorescent compound D05

[0110]

[0111] The H NMR spectrum is 1 H NMR (500MHz, DMSO-d6) δ8.77(d,J=6.6Hz,4H),8.08(d,J=5.3Hz,2H),8.06(d,J=3.3Hz,4H),8.04(s,2H),7.97(s,2H),4.45( t,J=7.4Hz,4H),3.77(s,3H),3.35–3.26(m,4H),3.07(s,18H),1.91(q,J=7.3Hz,4H),1.74–1.67(m,4H),1.36–1.31(m,8H).

[0112] The carbon NMR spectrum is 13 C NMR(126MHz,DMSO-d6)δ166.90,155.94,143.70,142.97,136.71,125.69,122.86, 122.59,119.21,109.57,65.57,59.16,52.64,44.19,30.64,25.41,22.65,22.31.

[0113] High-resolution mass spectrum: HRMS (ESI) m / z [M / 4] 4+calcd for C40H60N4O34+, theoretical value 161.1161; measured value: 161.1161.

[0114] Synthesis of fluorescent compound D06

[0115]

[0116] The H NMR spectrum is 1 H NMR(500MHz,DMSO-d6)δ8.79(d,J=6.6Hz,4H),8.05(t,J=8.9Hz,8H),7.96(s,2H),7 .74(d,J=7.7Hz,4H),7.51(d,J=7.6Hz,4H),5.69(s,4H),3.76(s,3H),1.29(s,24H).

[0117] The carbon NMR spectrum is 13 C NMR(126MHz,DMSO-d6)δ170.86,166.87,156.33,143.73,138.42,136.95,135.61,13 5.29,128.39,127.87,125.74,122.88,119.21,109.83,84.33,60.24,51.55,25.09.

[0118] Mass spectrum: HRMS (ESI) m / z [M] 2+ calcd for C48H54B2N2O72+, theoretical value 792.4106; measured value: 792.4135.

[0119] Synthesis of fluorescent compound D07

[0120]

[0121] The H NMR spectrum is 1 H NMR(500MHz,DMSO-d6)δ8.69(d,J=6.5Hz,4H),8.06(d,J=15.7Hz,2H),7.97(d,J=6.4Hz,4H),7 .77(d,J=15.7Hz,2H),7.32(s,2H),4.47(t,J=7.0Hz,4H),2.18(m,J=8.7Hz,8H),2.08(s,6H).

[0122] The carbon NMR spectrum is 13C NMR (126MHz, DMSO-d6) δ155.28,143.73,141.11,134.74,128.64,125.66,122.49,121.18,119.00,58.35,44.21,29.97,20.57,14.96.

[0123] High-resolution mass spectrum: HRMS (ESI) m / z [M] 2+ calcd for C29H36N2OS22+, theoretical value 492.2258; measured value: 492.2209.

[0124] Synthesis of fluorescent compound D08

[0125]

[0126] The H NMR spectrum is 1 H NMR (500MHz, DMSO-d6) δ8.64(d,J=6.5Hz,4H),8.05(d,J=15.6Hz,2H),7.95(d,J=6.5Hz,4H),7.85(d,J=15.7 Hz,2H),7.41(d,J=7.5Hz,2H),4.80(s,2H),4.47(t,J=7.1Hz,4H),3.48–3.43(m,4H),2.04(p,J=6.5Hz,4H).

[0127] The carbon NMR spectrum is 13 C NMR (126MHz, DMSO-d6) δ155.59, 143.72, 142.16, 142.05, 132.99, 126.17, 122.67, 122.21, 118.37, 57.61, 44.24.

[0128] High-resolution mass spectrum: HRMS (ESI) m / z [M] 2+ calcd for C26H30N2O32+, theoretical value 209.1122; measured value: 209.1119.

[0129] Synthesis of fluorescent compound D09

[0130]

[0131] The H NMR spectrum is 1H NMR (500MHz, DMSO-d6) δ8.69(d,J=6.8Hz,4H),8.05(d,J=5.1Hz,4H),8.03(d,J=2.5Hz,4H),7.96( s,2H),4.77(s,2H),4.49(t,J=7.0Hz,4H),3.77(s,3H),3.46(q,J=3.5Hz,4H),2.09–1.98(m,4H).

[0132] The carbon NMR spectrum is 13 C NMR (126MHz, DMSO-d6) δ177.94,166.91,155.82,143.87,142.78,136.55,125.68,122.50,119.21,109.60,57.60,51.51,44.18,33.64.

[0133] High-resolution mass spectrometry: HRMS (ESI) m / z [MH] 2+ calcd for C28H32N2O52+, theoretical value 476.2300; measured value: 475.2237.

[0134] Synthesis of fluorescent compound D10

[0135]

[0136] The H NMR spectrum is 1 H NMR (500MHz, DMSO-d6) δ8.63(d,J=6.5Hz,4H),8.01(d,J=15.6Hz,2H),7.90(d,J=6.5Hz,4H),7.84(d,J=1 5.6Hz,2H),7.22(s,2H),4.46(t,J=7.0Hz,4H),3.45(t,J=5.8Hz,4H),2.15(s,3H),2.02(p,J=6.4Hz,4H).

[0137] The carbon NMR spectrum is 13 C NMR (126MHz, DMSO-d6) δ155.60,144.38,143.59,142.32,135.69,125.87,121.92,118.83,117.61,57.49,44.15,33.72,22.86.

[0138] High-resolution mass spectrum: HRMS (ESI) m / z [M / 2] 2+ calcd for C27H32N2O32+, theoretical value 216.1201; measured value: 216.1205.

[0139] Synthesis of fluorescent compound D11

[0140]

[0141] The H NMR spectrum is 1 H NMR (500MHz, DMSO-d6) δ8.73(d,J=6.6Hz,4H),8.09(d,J=15.8Hz,2H),8.02(d,J=5.3Hz,4H),7.75(d,J=15.8 Hz,2H),7.37(s,2H),4.49(t,J=7.1Hz,4H),3.49(t,J=6.6Hz,4H),2.21(s,3H),2.18(dd,J=13.3,6.4Hz,4H).

[0142] The carbon NMR spectrum is 13 C NMR (126MHz, DMSO-d6) δ154.17,153.99,144.68,137.26,137.08,131.27,124.83,123.98,123.05,57.68,56.83,49.04,48.11,30.09,20.62.

[0143] High-resolution mass spectrum: HRMS (ESI) m / z [M] 2+ calcd for C27H30N8O2+, theoretical value 482.2532; measured value: 482.2482.

[0144] Synthesis of fluorescent compound D12

[0145]

[0146] The H NMR spectrum is 1 H NMR(500MHz,DMSO-d6)δ9.53(s,1H),8.77(d,J=6.6Hz,4H),8.07(d,J=6.7Hz,4H),8.04(d,J=2.4Hz ,4H),7.88(d,J=12.7Hz,2H),4.52(t,J=7.1Hz,4),3.49(dd,J=13.2,4.5Hz,4H),2.22–2.08(m,4H).

[0147] The carbon NMR spectrum is 13C NMR (126MHz, DMSO-d6) δ155.63,143.71,143.61,141.98,134.70,126.15,122.44,118.70,112.35,56.99,48.10,44.18,30.00,22.63.

[0148] High-resolution mass spectrum: HRMS (ESI) m / z [M] 2+ calcd for C26H28N8O2+, theoretical value 468.2375; measured value: 482.2482.

[0149] Synthesis of fluorescent compound D13

[0150]

[0151] The H NMR spectrum is 1 H NMR(500MHz,DMSO-d6)δ8.71(d,J=7.0Hz,4H),8.08(d,J=12.0Hz,2H),8.05(d,J=3.5Hz,4H), 8.04(d,2H),7.97(s,2H),4.48(t,J=7.1Hz,4H),3.48(t,J=6.5Hz,4H),2.17(p,J=6.8Hz,4H).

[0152] The carbon NMR spectrum is 13 C NMR(126MHz,DMSO-d6)δ170.88,166.90,156.17,155.99,143.83,142.81,1 36.48,125.69,122.66,119.32,60.25,57.12,51.56,48.08,29.96,21.23.

[0153] High-resolution mass spectrum: HRMS (ESI) m / z [M] 2+ calcd for C28H30N8O32+, theoretical value 526.2430; measured value: 526.2371.

[0154] Synthesis of fluorescent compound D14

[0155]

[0156] The H NMR spectrum is 1H NMR(500MHz,DMSO-d6)δ8.43(d,J=6.1Hz,4H),7.96–7.89(m,4H),7.84(d,J=6.4Hz,4H),7.37(d,J=16.0Hz,2H),5. 26(s,2H),4.45(t,4H),4.19(q,J=7.1Hz,2H),3.44(t,J=5.8Hz,4H),2.00(p,J=6.4Hz,4H),1.26(t,J=7.1Hz,3H).

[0157] The carbon NMR spectrum is 13 C NMR (126MHz, DMSO-d6) δ178.04,166.46,155.88,143.86,142.95,136.78,125.62,122.49,119.25,109.87,59.81,57.60,57.10,33.65,15.08.

[0158] High-resolution mass spectrum: HRMS (ESI) m / z [M] 2+ calcd for C29H28N2O52+, theoretical value 490.2457; measured value: 490.2435.

[0159] Synthesis of fluorescent compound D15

[0160]

[0161] The H NMR spectrum is 1 H NMR (500MHz, DMSO-d6) δ8.72(d,J=6.6Hz,4H),8.08(d,J=15.7Hz,2H),8.00(d,J=6.5Hz,4H),7.79(d,J= 15.7Hz,2H),7.33(s,2H),4.56(t,J=6.6Hz,4H),3.08(t,J=2.6Hz,2H),2.96–2.89(m,4H),2.19(s,3H).

[0162] The carbon NMR spectrum is 13 C NMR (126MHz, DMSO-d6) δ155.68,143.78,141.60,135.12,128.38,125.74,122.17,118.90,79.98,57.21,49.05,22.67,20.71.

[0163] High-resolution mass spectrometry: HRMS (ESI) m / z [M] 2+ calcd for C29H28N2O2+, theoretical value 420.2191; measured value: 420.2154.

[0164] Synthesis of fluorescent compound D19

[0165]

[0166] The H NMR spectrum is 1 H NMR (500MHz, DMSO-d6) δ8.79(d,J=6.9Hz,4H),8.16(s,2H),8.07(d,J=15.8Hz,2H),8.01(d,J=7.4Hz,4H),7.75 (dd,J=10.6,4.2Hz,4H),7.50(d,J=7.8Hz,4H),7.37(s,2H),5.69(d,J=13.4Hz,4H),2.20(s,3H),1.30(s,24H).

[0167] The carbon NMR spectrum is 13 C NMR(126MHz,DMSO-d6)δ155.83,143.52,138.54,137.05,135.61,135.30,12 8.36,127.85,125.88,122.48,120.19,118.22,84.33,60.23,25.10,21.24.

[0168] High-resolution mass spectrum: HRMS (ESI) m / z [M] 2+ calcd for C47H54B2N2O52+, theoretical value 748.4208; measured value: 748.4194.

[0169] Synthesis of fluorescent compound D24

[0170]

[0171] Compound D07 (0.5 mmol, 326.27 mg) was added to a reaction bottle, and then 5 ml of DMF was added. Then, iodomethane (4 mmol, 567.76 mg) was slowly added under a nitrogen atmosphere, and the reaction was allowed to proceed overnight at room temperature. After the reaction was completed, the reaction solution was slowly dripped into 15 ml of ethyl acetate solution, and the mixture was allowed to stand for 30 min. The precipitate was filtered, washed with ethyl acetate several times, and the compound was dried to obtain compound 24 (yellow solid, yield: 55.42%).

[0172] The H NMR spectrum is 1H NMR (500MHz, DMSO-d6) δ10.08(s,1H),9.03(d,J=6.4Hz,4H),8.30(d,J=6.4Hz,4H),8.26(d,J=16.1Hz,2H),7.75(s,2H) ,7.58(d,J=16.0Hz,2H),4.67(t,J=7.3Hz,4H),3.42(t,J=7.5Hz,4H),2.97(s,12H),2.47(t,J=7.4Hz,4H),2.36(s,3H).

[0173] The carbon NMR spectrum is 13 C NMR (126MHz, DMSO-d6) δ153.92,153.69,144.99,136.24,130.69,129.97,124.69,124.32,124.04,59.24,58.14,25.01,20.63,14.99.

[0174] High-resolution mass spectrum: HRMS (ESI) m / z [M / 4] 4+ calcd for C31H42N2OS24+, theoretical value 130.5679; measured value: 130.5685.

[0175] Synthesis of fluorescent compound D25

[0176]

[0177] The H NMR spectrum is 1 H NMR (500MHz, DMSO-d6) δ8.74–8.67(m,4H),8.19(s,1H),7.93(d,J=6.6Hz,2H),7.90–7.82(m,4H),7.73(d,J=7.7H z,4H),7.49(d,J=7.8Hz,2H),7.44(d,J=7.8Hz,2H),7.36(d,J=7.6Hz,2H),5.64(d,J=14.2Hz,4H),1.29(s,24H).

[0178] The carbon NMR spectrum is 13 C NMR(126MHz,DMSO-d6)δ156.23,156.13,143.45,138.55,137.06,135.61,13 5.29,128.32,127.81,126.41,126.38,122.36,117.83,84.34,60.72,25.09.

[0179] High-resolution mass spectrum: HRMS (ESI) m / z [M] 2+ calcd for C46H52B2N2O52+, theoretical value 367.2026; measured value: 367.2023.

[0180] Synthesis of fluorescent compound D27

[0181]

[0182] H NMR 1 H NMR (500 MHz, DMSO-d 6 )δ10.26(s,1H),8.79(d,J=6.8Hz,4H),8.28(s,2H),8.10(d,J=6.9Hz,4H),8.04(d,J=9.4 Hz,4H),4.80(s,2H),4.53(t,J=7.0Hz,4H),3.46(q,J=4.9,4.2Hz,4H),2.10–2.01(m,4H).

[0183] The carbon NMR spectrum is 13 C NMR (126 MHz, DMSO-d 6 )δ155.22,144.27,141.11,130.40,129.90,125.29,123.08,121.38,57.62,57.45.

[0184] Synthesis of fluorescent compound D28

[0185]

[0186] H NMR 1 H NMR (500 MHz, DMSO-d 6 )δ10.26(s,1H),8.89(d,J=6.7Hz,4H),8.30(s,2H),8.21–8.15(m,4H),8.14–8.05(m,4H), 4.57(t,J=7.4Hz,4H),3.50–3.42(m,4H),3.13(s,18H),2.45(td,J=12.1,10.0,5.9Hz,4H).

[0187] The carbon NMR spectrum is 13 C NMR (126 MHz, DMSO-d 6 )δ178.54,155.69,144.23,141.56,130.47,130.16,125.33,123.25,121.41,62.28,56.53,52.96,24.66.

[0188] Synthesis of fluorescent compound D29

[0189]

[0190] The H NMR spectrum is 1 H NMR(500MHz,DMSO-d6)δ8.70(d,J=6.6Hz,4H),8.07–8.01(m,6H),8.00–7.95(m,4H ),4.47(t,J=7.2Hz,4H),2.50(d,J=8.3Hz,4H),2.17(t,J=7.2Hz,4H),2.07(s,6H).

[0191] The NMR carbon spectrum is 13 C NMR (126MHz, DMSO-d6) δ155.38,144.18,141.30,130.41,130.02,128.50,125.30,123.19,121.39,58.67,30.18,29.96,22.63.

[0192] Synthesis of fluorescent compound D30

[0193]

[0194] The H NMR spectrum is 1 H NMR(500MHz,DMSO-d6)δ8.70(d,J=6.6Hz,4H),8.03(q,J=7.5,6.4Hz,6H),8.01–7.93(m,4H), 4.47(t,J=7.2Hz,4H),3.77(s,3H),2.52(d,J=2.0Hz,4H),2.17(t,J=7.2Hz,4H),2.07(s,6H).

[0195] The NMR carbon spectrum is 13 C NMR (126MHz, DMSO-d6) δ178.02,166.89,155.98,143.77,136.71,128.46,125.69,122.60,119.24,109.60,58.39,51.51,29.96,22.75,14.94.

[0196] Synthesis of fluorescent compound D31

[0197]

[0198] The H NMR spectrum is 1H NMR(500MHz,DMSO-d6)δ10.26(s,1H),8.87(d,J=6.7Hz,4H),8.29(s,2H),8.17(s,4H),8.15–8.10(m ,2H),8.05(d,J=10.3Hz,2H),7.84(d,J=7.9Hz,4H),7.45(d,J=8.0Hz,4H),5.68(s,4H).1.30(s,24H)

[0199] Synthesis of fluorescent compound D32

[0200]

[0201] The H NMR spectrum is 1 H NMR (500MHz, DMSO-d6) δ10.26(s,1H),8.89(d,J=6.6Hz,4H),8.30(s,2H),8.15(d,J=6.7Hz,4H),8.08(d,J=13.5Hz,4H ),4.53(t,J=7.3Hz,4H),3.34(d,J=14.9Hz,18H),1.98(dd,J=14.0,6.4Hz,41H),1.85–1.61(m,4H),1.45–1.25(m,4H).

[0202] Synthesis of fluorescent compound D33

[0203]

[0204] The H NMR spectrum is 1 H NMR (500MHz, DMSO-d6) δ10.26(s,1H),8.89(t,J=7.5Hz,4H),8.29(s,2H),8.14(d,J=6.8Hz,4H),8.07(d,J=13.1 Hz,4H),4.56–4.48(m,4H),3.37–3.30(m,18H),3.08(s,4H),1.95–1.92(m,4H),1.69(s,4H),1.46–1.27(m,8H).

[0205] According to the above characterization data, the structural formula of the obtained water-soluble photosensitizer with antibacterial activity is shown in Formula IV, denoted as D28.

[0206]

[0207] Application examples:

[0208] This embodiment is used to characterize the performance of the above fluorescent compound, including:

[0209] (1) Visible light absorption performance:

[0210] Table 1

[0211]

[0212]

[0213]

[0214]

[0215] (2) Singlet oxygen generation ability test of fluorescent compounds: 30 μL of dimethyl sulfoxide (DMSO) stock solution of fluorescent compounds was added to 3 mL of ethanol solution, and 150 μL of singlet oxygen scavenger DPBF stock solution was added to the above solution, so that the final concentration of the photosensitizer (fluorescent compound) was 10 -5 mol / L, the concentration of singlet oxygen indicator is 5 times that of photosensitizer, the absorption spectrum of the mixed solution at 412nm is measured, and then the mixed solution is illuminated with 525-550nm LED light (light power is 400mw), and the absorption spectrum of the mixed solution at 412nm is measured as a function of illumination time. The group with only DPBF is used as the blank control group. The results are as follows Figures 2 to 5 and Figure 6 shown. Figure 6 is the change of DPBF with illumination time, Figure 2 The absorbance value of the mixed solution with photosensitizer added at 412nm changes with the illumination time. Figures 2 to 5 and Figure 6 It can be seen that with the extension of illumination time, the absorption value of the blank DPBF group has no obvious change, but in the presence of the photosensitizer of this example, the absorption value of the singlet oxygen scavenger DPBF decreases significantly, indicating that this type of photosensitizer has a strong ability to produce singlet oxygen.

[0216] (3) Test of the photodynamic killing ability of fluorescent compounds on MRSA:

[0217] The specific steps are as follows

[0218] Sample preparation: DMSO was used as solvent to prepare a 6.4 mg / mL fluorescent compound stock solution; an appropriate amount of the stock solution was diluted to 256 μg / mL with MHB medium as the sample solution; the antibacterial drug vancomycin was selected as the positive control compound. The sample solution was added to a 96-well plate and diluted in an equal gradient with MHB medium (128 μg / mL→1 μg / mL). MRSA (ATCC43300) bacterial solution was added and mixed by shaking for 3 minutes before culturing.

[0219] Dark group: sealed with tin foil and protected from light, placed in a 37℃ incubator for 17h; light group: sealed with tin foil and protected from light, placed in a 37℃ incubator for 30min, then irradiated with 500-510nm / 570-590nm light for 30min in the 96-well plate, and then placed in an incubator for 16h.

[0220] The test results were determined by visually inspecting the colony formation and OD600 in the 96-well plate.

[0221] Table 2

[0222]

[0223]

[0224] Table 2 shows the photodynamic killing of methicillin-resistant Staphylococcus aureus by photosensitizers. As can be seen from Table 2, the survival rate of methicillin-resistant Staphylococcus aureus in the phototoxic group decreased significantly, and the survival rate of methicillin-resistant Staphylococcus aureus in the dark toxic group decreased, but the survival rate was still very high, indicating that the photosensitizer has a significant photodynamic killing effect on methicillin-resistant Staphylococcus aureus, especially the fluorescent compound D28 has a very significant photodynamic killing effect.

[0225] (4) For the photodynamic killing ability test of E. coli, the specific steps are as follows:

[0226] DMSO was used as solvent to prepare 6.4 mg / mL compound stock solution; an appropriate amount of stock solution was diluted to 256 μg / mL with MHB medium as sample solution; the antibacterial drug ciprofloxacin was selected as the positive control compound. The compound sample solution was added to a 96-well plate and diluted with MHB medium in an equal gradient (128 μg / mL→1 μg / mL). E. coli (ATCC25922) bacterial solution was added and cultured after oscillation and mixing for 3 minutes. Dark group: sealed with tin foil and placed in a 37°C incubator for 17 hours; light group: sealed with tin foil and placed in a 37°C incubator for 30 minutes, then irradiated with 500-510nm / 570-590nm light for 30 minutes in the 96-well plate, and then placed in the incubator for 16 hours. The test results were determined by visually observing the colony formation of the 96-well plate and OD600.

[0227] Table 3

[0228]

[0229]

[0230] As can be seen from Table 3, the survival rate of E. coli in the phototoxic group decreased significantly, and although the survival rate of E. coli in the dark toxic group decreased, the survival rate was still very high, indicating that the photosensitizer had a significant photodynamic killing effect on E. coli, especially the fluorescent compound D28 had a very significant photodynamic killing effect.

[0231] from Figure 7 It can be seen from the middle line graph that the absorption intensity of DPBF at 412nm does not change substantially with the extension of illumination time. The singlet oxygen produced by the DPBF solution with the addition of compound D28 oxidizes DPBF very quickly with the extension of illumination time, and its ultraviolet absorption intensity at 412nm decreases significantly. By comparing with commercial RB, the ultraviolet absorption intensity at 412nm of the DPBF solution with the addition of commercial RB also decreases, but there is no significant decrease without the addition of compound D28, which proves that the ability of compound D28 to produce singlet oxygen is much stronger than that of commercial RB.

[0232] The water-soluble photosensitizer with broad-spectrum antibacterial activity provided by the present invention has a pyridinium salt or a pyridinium salt and a quaternary ammonium salt in its molecular structure, wherein the pyridinium salt or the quaternary ammonium salt makes the photosensitizer molecule positively charged, while the surface of the bacteria is negatively charged. Due to electrostatic interaction, the photosensitizer synthesized in the present invention can effectively combine with the bacteria, which lays a foundation for subsequent efficient killing; at the same time, the photosensitizer provided by the present invention has a strong singlet oxygen production ability; the photosensitizer synthesized in this article is used for photodynamic antibacterial. In addition, the photosensitizer of the present invention also has good water solubility, which helps to improve its biocompatibility and broaden its application range, and can be used to construct a photodynamic antibacterial drug with a broad-spectrum antibacterial effect. The present invention also provides a method for preparing a water-soluble photosensitizer with broad-spectrum antibacterial activity in the above-mentioned technical scheme. By sequentially performing a Heck reaction and a salt-forming reaction, a water-soluble photosensitizer with broad-spectrum antibacterial activity is prepared. The preparation method has simple steps, is easy to operate, and is suitable for industrial production.

[0233] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. An electron donor-dual acceptor fluorescent compound, characterized in that: The compound has the following structural formula: Wherein, R1 is at least one of the following functional groups: R2 is H, -CH3, -COOCH2CH3, -COOCH3 or -NO2; X1 is a halogen ion.

2. The electron donor-dual acceptor fluorescent compound according to claim 1, characterized in that: The compound has the following structural formula:

3. A method for preparing the electron donor-dual acceptor fluorescent compound according to claim 1 or 2, characterized in that: The method comprises the following steps: The compound shown in Formula 2 is mixed with the compound shown in Formula 3 and an organic base, and subjected to a Novegrin reaction to obtain the electron donor-dual acceptor type fluorescent compound.

4. The method for preparing the electron donor-dual acceptor fluorescent compound according to claim 3, characterized in that: The preparation method of the compound shown in Formula 2 comprises: A phenol compound as shown in Formula 1 and hexamethylenetetramine are mixed and subjected to a Williamson synthesis reaction.

5. The method for preparing the electron donor-dual acceptor fluorescent compound according to claim 4, characterized in that: In the Williamson synthesis reaction, the reaction conditions include at least one of the following conditions: A) the molar ratio of the phenol compound to hexamethylenetetramine is 1:(2.0-2.5); B) The reaction temperature is 100-120°C and the reaction time is 20-24h; C) The reaction solvent is trifluoroacetic acid.

6. The method for preparing the electron donor-dual acceptor fluorescent compound according to claim 3, characterized in that: The method for preparing the compound as shown in Formula 3 comprises: heating 4-methylpyridine and X1-R1 for reaction.

7. The method for preparing the electron donor-dual acceptor fluorescent compound according to claim 6, characterized in that: In the heating reaction, the reaction conditions include at least one of the following conditions: A) the molar ratio of the R1 group in X1-R1 to 4-methylpyridine is 1:(1-1.5); B) The reaction temperature is 80-95°C and the reaction time is 12-24h; C) The reaction solvent is acetonitrile.

8. The method for preparing the electron donor-dual acceptor fluorescent compound according to claim 3, characterized in that: The molar ratio of the compound shown in Formula 2 to the compound shown in Formula 3 is 1:(1.8-2.0); the molar ratio of the compound shown in Formula 2 to the organic base is 1:(2.0-2.5).

9. The method for preparing the electron donor-dual acceptor fluorescent compound according to claim 7, characterized in that: In the brain wenge reaction, the reaction temperature is 80-90°C and the reaction time is 1-3h.

10. Use of the electron donor-dual acceptor fluorescent compound as claimed in claim 1 or 2, characterized in that: The electron donor-dual acceptor type fluorescent compound is used for preparing antibacterial agents.

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