A pyran unit embedded bisanthene compound and a synthesis method thereof

Abstract

The application relates to the technical field of organic functional molecule synthesis, and particularly discloses a pyran unit embedded bisanthene compound and a synthesis method. The method takes compound 1 as raw material, and under the condition of a sodium borohydride and boron trifluoride ether collaborative reduction system and room temperature, a single selective edge pyran ring is constructed through carbonyl activation-hydrogen transfer-intramolecular cyclization, and the yield is 60%, and the atomic economy is high. The obtained compound A has a maximum absorption characteristic peak at 726 nm in dichloromethane, and a maximum emission characteristic peak at 960 nm; after being made into nanoparticles, the photo-thermal conversion efficiency reaches 53% under the irradiation of an 808 nm laser (0.5 W cm-2), and the photo-thermal stability is significantly improved. The synthesis route has the advantages of mild conditions, simple operation and high atomic economy, and provides a universal strategy for the functionalization of oxygen-doped fused ring arenes and the preparation of high-efficiency photo-thermal materials.

Description

Technical Field

[0001] This invention relates to a pyran unit-intercalated bisanthene compound and its synthetic method, belonging to the field of organic functional molecule synthesis technology. Background Technology

[0002] Nano-sized fused-ring aromatics (FRAs) exhibit great potential in electronic devices, bioimaging, and energy technologies due to their superior two-dimensional π-conjugated structure. By precisely doping with heteroatoms, their framework and electron cloud distribution can be reconstructed at the molecular level, thereby systematically controlling key properties such as redox activity, energy band gap, charge transfer, and photothermal conversion. However, compared to heteroatoms such as nitrogen, boron, sulfur, and silicon, cases of oxygen atoms embedded in the FRA framework remain scarce. Existing techniques show that directly introducing oxygen atoms into the FRA framework typically requires multiple high-energy reactions and is prone to ring-opening or deoxygenation due to the low C–O bond energy and high electron cloud density of the aromatic ring, resulting in low yields and limited varieties of edge oxygen-doped products. To date, there is still a lack of mild and highly selective general routes for precisely embedding oxygen-containing six-membered heterocycles—pyran units—into large π-fused rings, severely limiting the application of oxygen-doped FRAs in scenarios such as high-efficiency photothermal materials.

[0003] To address the aforementioned shortcomings, this invention, in conjunction with the reference title: Silver-Catalyzed C(sp) 2 A synthetic method based on HF-Functionalization / C-O Cyclization Reaction at Room Temperature was proposed, using a synergistic reduction system of sodium borohydride and boron trifluoride diethyl ether to achieve one-step reductive cyclization of compound 1: (i) boron trifluoride diethyl ether, acting as a Lewis acid, first coordinates with the carbonyl oxygen of the lactone, activating C=O and lowering its reduction potential; (ii) sodium borohydride provides highly active negative hydrogen, enabling the directional conversion of the carbonyl group to a hemiacetal at room temperature, and immediately undergoing intramolecular cyclization with the ortho-alkene to quantitatively form a pyran ring, while effectively suppressing side reactions such as alcohol hydrolysis and ring-opening under traditional reduction conditions. This method is mild, simple to operate, and highly atom-economical.

[0004] This invention discloses a method for synthesizing a pyran ring in one step in the bisanthene two-bay region using a synergistic reduction system of sodium borohydride and boron trifluoride diethyl ether. This method effectively suppresses alcohol hydrolysis byproducts and selectively prepares compound A. The obtained compound A is then prepared into nanoparticles as a photothermal agent, achieving a photothermal conversion efficiency of 53% and significantly improved photothermal stability.

[0005] To address the above problems, this invention provides a pyran unit-embedded bisanthene compound and its synthesis method, which has the advantages of mild conditions, simple operation, and high atom economy.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] A compound with a pyran unit embedded in bisanthene has the following structure:

[0008]

[0009] A method for synthesizing a pyran unit-intercalated bisanthene compound, comprising the following steps: using compound 1 as a starting material, compound A is obtained through the synergistic catalysis of sodium borohydride and boron trifluoride diethyl ether. The synthetic steps of this compound are as follows:

[0010]

[0011] The synthesis method of A mentioned above specifically includes the following steps:

[0012] According to the mass ratio of compound 1: sodium borohydride: boron trifluoride diethyl ether = 1:0.57:8.38, it was dissolved in tetrahydrofuran solvent. The reaction mixture was stirred at 65°C for 5 hours. After the reaction was completed, saturated ammonium chloride solution was added for quenching. The organic phase was extracted with dichloromethane and water, and the solvent was removed under reduced pressure. Using a mixed solvent of petroleum ether and dichloromethane at a volume ratio of 10:1 as the eluent, the mixture was separated by 200-300 mesh neutral silica gel column chromatography. The second blue band was collected to obtain a solution of compound A. The solvent was then recovered by reduced pressure distillation, and the solution was dried under vacuum to obtain a blue-black solid compound A.

[0013] The beneficial effects of this invention are as follows:

[0014] (1) The present invention synthesizes a pyran unit-intercalated bisanthene compound, which has excellent stability and good modifiability.

[0015] (2) The synthesis method of the present invention has the advantages of mild conditions, simple operation and high atom economy.

[0016] (3) The synthesis method of the present invention effectively suppresses the generation of alcohol hydrolysis byproducts in traditional reduction reactions, realizes the single selective synthesis of reduction products, and significantly improves reaction efficiency and product purity. Attached Figure Description

[0017] Figure 1 This is the synthetic route diagram for compound A.

[0018] Figure 2 This is the 1H NMR spectrum of compound 1.

[0019] Figure 3 This is the 1H NMR spectrum of compound A.

[0020] Figure 4 This is the single-crystal structure diagram of compound A.

[0021] Figure 5 The UV-Vis absorption spectra of compound A in different solvents are shown.

[0022] Figure 6 For compound A at a concentration of 1×10 -5 UV-Vis absorption and fluorescence emission spectra under M conditions.

[0023] Figure 7 The figure shows the concentration-dependent photothermal heating curve of nanoparticle A under irradiation with an 808 nm laser (0.5 W cm⁻²).

[0024] Figure 8 The graph shows the thermal conversion efficiency of nanoparticles of compound A.

[0025] Figure 9 The photothermal stability experiment of compound A nanoparticles. Detailed Implementation

[0026] The raw material 1 used in this invention was synthesized using the preparation method described in the reference entitled "Synthesis and Properties of Lactone Embedded Bisanthene," and its proton nuclear magnetic resonance (NMR) spectrum data are as follows: Figure 2 The image shows the 1H NMR spectrum of compound 1. 1 H NMR (600 MHz, C6D6) δ (ppm) = 8.46 (d, J = 9.0 Hz, 2H), 7.75 (d, J = 9.3 Hz, 2H), 7.68 (d, J = 9.0 Hz, 2H), 7.37 (d, J = 9.2 Hz, 2H), 7.10 – 7.06 (m, 4H), 2.40 (s, 6H), 1.91 (s, 6H), 1.81 (s, 6H).

[0027] This embodiment

[0028] Synthesis of Compound A: 67.1 mg (0.1 mmol) of Compound 1, 38.0 mg (1 mmol) of sodium borohydride, 0.5 mL (4 mmol) of boron trifluoride diethyl ether, and 5 mL of tetrahydrofuran were added to a 20 mL double-necked flask. The reaction mixture was stirred at 65 °C for 5 hours. After the reaction was completed, saturated ammonium chloride solution was added to quench the reaction. The organic phase was extracted with dichloromethane and water, and the solvent was removed under reduced pressure. Separation was performed by 200-300 mesh neutral silica gel column chromatography using a 10:1 (v / v) mixture of petroleum ether and dichloromethane as eluent. The second blue band was collected to obtain a solution of Compound A. The solvent was then recovered by reduced pressure distillation, and the solution was dried under vacuum to obtain a blue-black solid, Compound A. The total yield was 38.5 mg, with a yield of 60%.

[0029] Structural characterization of compound A: 1. Figure 3 Here is the 1H NMR spectrum of compound A: 1 H NMR (600 MHz, THF- d 8 ) δ (ppm) = 7.10 (s, 4H), 7.08 (d, J = 9.3 Hz, 2H), 6.98 (d, J = 1.6 Hz, 3H), 6.86 (d, J = 9.2 Hz, 2H), 5.69 (s, 4H), 2.41 (s, 6H), 1.88 (d, J = 3.1 Hz, 12H). 2. Figure 4 The image shows the single-crystal structure of compound A. The single crystal of compound A was cultured using the solvent diffusion method. The specific steps are as follows: First, 0.1 mL of a 10... -3 A dichloromethane solution of compound A (M) was filtered through an organic microporous membrane with a pore size of 0.45 μm and then added to a smooth glass tube with an inner diameter of 5 mm and a length of 10 mm. This glass tube was then placed inside a sealed glass bottle (outer diameter 20 mm, height 80 mm) containing 2 mL of n-hexane, ensuring the opening of the glass tube was above the hexane level. Finally, the glass tube was placed at an angle inside the small glass bottle and stored in a cool, dark, and vibration-free environment. After 3 days of slow evaporation and diffusion, a single crystal with a regular morphology was finally obtained. 3. Figure 5 The UV-Vis absorption spectra of compound A in different solvents are shown, using a concentration of 1×10⁻⁶. -5Compound A of M was tested. The UV-Vis and near-infrared absorption spectra in different solvents (n-hexane, toluene, dichloromethane, ethyl acetate, and tetrahydrofuran) were measured using a SHIMADZU UV-2600i UV-Vis spectrophotometer. The maximum absorption wavelength of compound A was 726 nm. 4. Figure 6 For compound A at a concentration of 1×10 -5 The UV-Vis absorption and fluorescence emission spectra under M conditions showed that compound A exhibited a positive solvation effect in different solvents. Compound A at a concentration of 1×10⁻⁶ was analyzed using a HITACHI F-4700 fluorometer. -5 The fluorescence emission spectrum under M conditions shows that compound A has a fluorescence emission range of 702-1400 nm, with a maximum emission peak at 960 nm.

[0030] Performance testing of compound A: 1. Preparation of A nanoparticles: 2 mg of compound A and 10 mg of DSPE-PEG were mixed. 2000 Dissolved in 2 mL of tetrahydrofuran solution, then poured into 10 mL of double-distilled water and sonicated (150 W). The resulting dispersion was then sonicated (150 W) for 5 minutes. Subsequently, dialyzed for 12 hours to obtain a homogeneous and transparent dark blue or dark green micelle solution, which was then filtered using a 0.45 μm polyvinylidene fluoride syringe. The resulting concentrated nanoparticle solution could be diluted with phosphate buffer solution. Finally, the nanoparticles were stored at 4°C for subsequent use. 2. Figure 7 The figure shows the concentration-dependent photothermal heating curve of nanoparticle A under 808 nm laser irradiation (0.5 W cm⁻²). Under 808 nm laser irradiation (power density of 0.5 W cm⁻², irradiation time of 4 minutes), the temperature of nanoparticle A rises rapidly, reaching 81.22 °C at a concentration of 200 µM. The temperature increase of nanoparticle A is positively correlated with its concentration and laser power density, indicating that heat generation can be effectively controlled by adjusting these parameters. 3. Figure 8 The thermal conversion efficiency of compound A nanoparticles is shown. Using the method reported in the literature (Highly Stable Near-Infrared II Luminescent Diradicaloids for Cancer Phototheranostics), the photothermal conversion efficiency of nanoparticle A was calculated to be 53%. 4. Figure 9 To test the photothermal stability of compound A nanoparticles, four heating-cooling cycles were performed under continuous laser irradiation to verify the photothermal stability of the nanoparticles. The highest temperature remained consistent in each cycle, demonstrating good photothermal stability.

[0031] Obviously, the above embodiments are merely illustrative of the present invention and do not limit the implementation of the present invention. For those skilled in the art, other variations or adjustments can be made based on the above description. It is impossible to exhaustively list all embodiments here; any obvious variations or adjustments that pertain to the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. A pyran unit-intercalated bisanthene compound, characterized in that, The structure is as follows: 。 2. A method for synthesizing a pyran unit-intercalated bisanthene compound as described in claim 1, characterized in that, Compound A was obtained via the following synthetic route. 。 3. A method for synthesizing a pyran unit-intercalated bisanthene compound as described in claim 2, characterized in that, In the reaction of compound 1 with sodium borohydride to produce compound A, the mass ratio of compound 1 to sodium borohydride is 1:0.57, the mass ratio of compound 1 to boron trifluoride diethyl ether is 1:8.38, the solvent is tetrahydrofuran at a concentration of 50 L / mol of compound 1, the reaction temperature is 65℃, and the reaction time is 5 hours. After the reaction is completed, the reaction system is purified by extraction, drying, filtration, vacuum distillation, and silica gel column chromatography to obtain product A.

4. An application of a pyran unit-intercalated bisanthene compound as described in claim 1, characterized in that, The synthesized compound A was made into nanoparticles and used as a photothermal agent. In the photothermal performance test, it showed high stability and a photothermal conversion efficiency of 53%.

Images