3-imido-4, 5-diaryl boron oxygen heterocyclic onium salt derivative as well as preparation method and application thereof

Abstract

The invention discloses a 3-imido-4, 5-diaryl boron oxygen heterocyclic ring onium salt derivative as well as a preparation method and application of the 3-imido-4, 5-diaryl boron oxygen heterocyclic ring onium salt derivative. The 3-imido-4, 5-diaryl boron oxygen heterocycle onium salt derivative is prepared by taking acetylenic ketone potassium fluoborate, organic amine and 2-(trimethylsilyl) phenyl trifluoromethanesulfonate as raw materials, inorganic alkali and a weak acid buffer as accelerators and water and acetonitrile as solvents through a one-pot two-step reaction, and the compound can be used for preparing organic fluorescent materials, such as organic fluorescent materials, organic fluorescent materials, organic fluorescent materials, organic fluorescent materials, organic fluorescent materials and organic fluorescent materials. The compound has obvious aggregation-induced emission (AIE) property, high quantum yield and wider fluorescence range. The target product is prepared with high atom economy reaction and high yield, and the method has the advantages of cheap and easily available raw materials, mild reaction conditions, short synthetic route, wide universal range of substrates and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of the synthesis of organic fluorescent materials, and particularly relates to 3-imino-4,5-diarylboroxolium salt derivatives, and a preparation method and application thereof. Background Art

[0002] Conjugated boracycle molecules can form oxonium salts with neighboring heteroatoms by virtue of the Lewis acidity of boron, leading to significant changes in optoelectronic properties, and having great potential applications in the fields of fluorescent materials and chemical biology. The most common π-conjugated boracycles contain N,N- or O,O-bidentate chelating structures, such as classical BODIPY, Formazanate-BF2, and curcumin fluoroborate (Structural modification strategies for the rational design of red / NIR region BODIPYs. Chem. Soc. Rev. 2014, 43, 4778; Photostable small-molecule NIR-II fluorescent scaffolds that cross the blood-brain barrier for noninvasive brain imaging. J. Am. Chem. Soc. 2022, 144, 23668). A series of important progress has also been made in the research of another type of π-conjugated boracycles containing C-B←O structural units. For example, the ortho-formyltriarylboron developed by the teams of Wang Suning and Chen Pangkuan, etc., in which the intramolecular B←O coordination can make multiple responses to changes in the external environment (A simple multi-responsive system based on aldehyde functionalized amino-boranes. Chem. Sci. 2018, 9, 1902). However, the synthesis of this compound often requires multiple steps, and its molecular structure is easily reversibly transformed by external environments such as light, heat, and force. Optimizing the design of the C,O-boracycle skeleton and synthesizing boroxole molecules with good photo, thermal, and chemical stabilities will help to expand their applications in the biomedical field.

[0003] In 2014, the research groups of Ohmiya and Sawamura reported the trialkylphosphine-catalyzed anti-carboboration of alkynoates, and efficiently synthesized five-membered boron oxacycles via a one-pot method using pre-prepared R-BBN as the boration reagent (Equation 1A, Phosphine-catalyzed anti-carboboration of alkynoates with alkyl-, alkenyl-, and arylboranes. J. Am. Chem. Soc. 2014, 136, 10605). Among them, intermolecular O-B coordination activation and subsequent intramolecular R-group migration are the key to C-C sp bond formation. The resulting boron-containing product has a resonating enone structure and exhibits better chemical stability. Although both the regioselectivity and stereoselectivity of this reaction are guaranteed, the rigid dialkylboron (BBN) is retained in the product, making it difficult to convert for subsequent functional group modification.

[0004] In 2017, the Uchiyama research group discovered that tertiary propargyl alcohols could directly undergo a trans-alkynylboration reaction with phenyl ethynylboronic esters without the catalysis of small molecules (Equation 1B, Transition metal-free trans-selective alkynylboration of alkynes. J. Am. Chem. Soc. 2017, 139, 12358). On this basis, the Santos and Uchiyama research groups respectively achieved the β-boration reaction of propiolamides using hydroborate esters and phenyl ethynylboronic esters to obtain the corresponding five-membered C,O-boracycle products (Equation 1C, trans-Hydroboration of propiolamides: access to primary and secondary (E)-β-borylacrylamides. Org. Lett. 2019, 21, 6795; Alkynylboration reaction leading to boron-containing π-extended cis-stilbenes as a highly tunable fluorophore. Org. Lett. 2019, 21, 3392). The method reported by the Uchiyama research group in 2019 synthesized a class of boron-oxygen heterocyclic derivatives containing tetrasubstituted enamide, which had obvious aggregation-induced emission (AIE) and intramolecular charge transfer (ICT) effects. However, the limitations of the above reactions are as follows: 1) The electronic effect of tertiary aryl propargyl alcohols has an obvious influence on the reaction activity, and the reaction does not occur when the benzene ring is connected with electron-donating substituents; 2) The borate ester substrate is relatively easy to hydrolyze, so strict anhydrous conditions are required, which reduces the operational convenience; 3) Boracycle derivatives containing 1,2-diphenylethylene fragments have not been obtained by the above method.

[0005]

[0006] In 2023, the Luo Deping team developed a class of potassium alkynone fluoroborate coupling reagents with amine specificity, realizing the selective multiple modification of natural proteins at lysine and terminal amino sites (Equation 2, Alkynone β-trifluoroborates: A new class of amine-specific biocompatible click reagents. Sci. Adv. 2023, 9, eadg4924). The coupling product showed good performance in chemical stability experiments, and when π-conjugated functional groups (such as pyrenyl) were introduced into the product structure, it had obvious solution fluorescence effects (λ em = 470 nm, Φ FL= 44.6% in THF). However, the two-component cyclization product obtained through the "alkynone-amine" click reaction has a hydrogen atom directly connected to the C-4 position, resulting in very low luminescence efficiency in the solid state.

[0007] SUMMARY OF THE INVENTION

[0008] The object of the present invention is to disclose a 3-imino-4,5-diarylboroxolium salt derivative, its preparation method and application. The advantages of the present invention are that the raw materials are inexpensive and easily available, the reaction conditions are mild, the one-pot method is adopted to shorten the preparation route, and the generated product has good solid-state luminescence properties.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0010] The present invention uses potassium fluoroborate alkynone, organic amine and 2-(trimethylsilyl)phenyl trifluoromethanesulfonate as raw materials, inorganic base and weak acid buffer as promoters, and water and acetonitrile as solvents. A new compound 3-imino-4,5-diarylboroxolium salt derivative is prepared through a one-pot two-step reaction, and its structure is as follows

[0011]

[0012] Among them, R 1 is a substituted phenyl or alkenyl, Ar is a substituted phenyl, R 2 is any substituent, and X is a halogen atom, cyano group or alkoxy group.

[0013] Preferably, R 1 is a substituted phenyl, naphthyl, pyrenyl, 2-thienyl, 2-benzothienyl or styryl, R 2 is any common group, including but not limited to: benzyl, alkyl, propargyl, α-ester-substituted alkyl or aryl, Ar is a 3,6-disubstituted, 4,5-disubstituted, 5-substituted or unsubstituted phenyl, and X is a halogen atom, cyano group or alkoxy group.

[0014] The present invention also provides a preparation method of the 3-imino-4,5-diarylboroxolium salt derivative, and the steps are as follows:

[0015] 1) Mix potassium fluoroborate alkynone and organic amine, then add water, stir at 36-38 °C for 2-24 hours, then remove the solvent by rotary evaporation under reduced pressure at 30-50 °C, and dry in a vacuum drying oven for 2-2.5 hours to obtain a crude product of 3-imino-5-arylboroxole;

[0016] 2) In a glove box filled with high-purity argon (99.9999%), the above-mentioned crude product is mixed with an inorganic base and a weak acid buffer, then acetonitrile and 2-(trimethylsilyl)phenyl trifluoromethanesulfonate are added, and the mixture is vigorously stirred at room temperature for 24 to 26 hours. Then, the solvent is removed by rotary evaporation at 30 to 50 °C, and the target product is obtained by column chromatography separation. The high-purity 3-imino-4,5-diarylboroxolium salt derivative is obtained by recrystallization with a solvent.

[0017] The reaction process formula of the preparation method:

[0018]

[0019] Further, the molar ratio of the raw materials is as follows: potassium alkynone fluoroborate: organic amine: 2-(trimethylsilyl)phenyl trifluoromethanesulfonate: inorganic base: weak acid buffer = 1: 1.4 - 1.6: 1.4 - 1.6: 2.4 - 2.6: 1.9 - 2.1.

[0020] Preferably, the molar ratio of the raw materials is as follows: potassium alkynone fluoroborate: organic amine: 2-(trimethylsilyl)phenyl trifluoromethanesulfonate: inorganic base: weak acid buffer = 1: 1.5: 1.5: 2.5: 2.

[0021] Further, in step 1), the dosage ratio of water to potassium alkynone fluoroborate is 0.4 - 0.5 mL: 0.1 mmol.

[0022] Further, in step 2), the dosage ratio of acetonitrile to potassium alkynone fluoroborate is 0.8 - 0.9 mL: 0.1 mmol.

[0023] Further, the potassium alkynone fluoroborate is potassium alkynone fluoroborate containing any one of a substituted phenyl group, a naphthyl group, a pyrenyl group, a 2-thienyl group, a 2-benzothienyl group, and a styryl group.

[0024] Further, the organic amine is any one of a substituted benzylamine, an alkylamine, a propargylamine, an α-amino acid ester, and a substituted aromatic amine.

[0025] Further, the 2-(trimethylsilyl)phenyl trifluoromethanesulfonate is a phenyl group with 3,6-disubstitution, 4,5-disubstitution, 5-substitution, or no substituent.

[0026] Further, the inorganic base is any one of cesium fluoride, potassium fluoride, sodium fluoride, ammonium fluoride, tetrabutylammonium fluoride, tetrabutylammonium bis(trifluoromethylsulfonyl)imide (TBAT), potassium carbonate, and cesium carbonate.

[0027] Further, the weak acid buffer is any one of potassium bifluoride, hexafluoroisopropanol, trifluoroethanol, and 18-crown-6.

[0028] Further, in step 2), column chromatography separation is carried out using a mixed solvent of ethyl acetate and n-hexane.

[0029] The reaction yield of the preparation method of the present invention is 40-93%, and the E / Z configuration ratio is 1:20 - 20:1.

[0030] The 3-imino-4,5-diarylboroxolenium salt derivative prepared by the present invention can be used to prepare organic fluorescent materials.

[0031] The present invention has the following beneficial effects: The raw materials potassium alkynone tetrafluoroborate, organic amine and 2-(trimethylsilyl)phenyl trifluoromethanesulfonate of the present invention are all inexpensive and easily available. The preparation method of the present invention is carried out at room temperature to 37 °C, and water and acetonitrile are used as solvents. The reaction conditions are green and mild, the experimental operation is simple, and the one-pot method is adopted without separating intermediate products. In the prior art, the preparation of similar compounds requires the use of easily hydrolyzable borate esters or 9-BBN borane substrates that are difficult to modify and transform, and the reaction scope is limited. In the present invention, the potassium alkynone tetrafluoroborate reagent is stable to water and oxygen, and fully substituted boroxolenium salts with structural diversity are synthesized modularly by the one-pot method, and the B-F bond of the generated product is easy to transform. The preparation method of the present invention is easy to be applied to industrial scale production.

[0032] The 3-imino-4,5-diarylboroxolenium salt derivative prepared by the present invention has good aggregation-induced emission effect. In the prior art, similar compounds are obtained only through the two-component reaction of "boron-containing alkynone-amine" to obtain boroxolenium salts containing styrene structures, and the C-4 position is directly connected to hydrogen. At this time, the closed-ring product has a low luminescence efficiency in the solid state. The preparation method of the present invention uses a three-component reaction of "boron-containing alkynone-amine-benzyne" to obtain fully substituted boroxolenium salts containing 1,2-distyrene structures. The main principle is to capture highly active benzyne through in-situ generated β-aminoenone to selectively generate C-arylated products. Since the non-coplanar adjacent benzene rings in the product can inhibit fluorescence quenching caused by π-π stacking, and the molecular motion is restricted in the solid state, it has an obvious solid-state luminescence effect. Description of the Drawings

[0033] Figure 1 It is the AIE characteristic of compound 5a in a water / tetrahydrofuran mixed solution. Detailed Embodiments

[0034] The following further describes the present invention in detail with specific examples. The processes, conditions, reagents, experimental methods, etc. for implementing the present invention are all common knowledge and well-known common sense in the art except for the specifically mentioned content below, and the present invention has no particularly restricted content.

[0035] Example 1

[0036] Under an air atmosphere, 1a (23.6 mg, 0.1 mmol) of ethynyl ketone potassium fluoroborate, 2a (16 μL, 0.15 mmol) of benzylamine and 0.4 mL of water were weighed and added to a 4 mL reaction flask, and stirred at 37 °C for about 2 hours until 1a completely disappeared. Subsequently, the crude product was concentrated under reduced pressure and dried in vacuo (1 - 2 h), dissolved in 0.8 mL of acetonitrile and transferred to a 10 mL reaction tube. Under argon protection, CsF (38.0 mg, 0.25 mmol), KHF2 (15.6 mg, 0.2 mmol) and phenylacetylene precursor 4a (44.8 mg, 0.15 mmol) were added in sequence, and stirred vigorously at room temperature for 24 hours. Column chromatography was used for rapid separation and purification (ethyl acetate / n - hexane = 1:5), and after concentration under reduced pressure, a yellow solid 5a was obtained with a yield of 81%, E / Z > 95:5. 1 1H NMR (600 MHz, CD3CN): δ 8.10 (s, 1H), 7.58 (d, J = 8.5 Hz, 2H), 7.49 (t, J = 7.5 Hz, 1H), 7.44 - 7.39 (m, 3H), 7.38 - 7.29 (m, 7H), 7.16 (d, J = 6.7 Hz, 2H), 4.78 (d, J = 6.6 Hz, 2H). 13 13C NMR (100 MHz, CD3CN): δ 184.2, 137.4, 133.6, 132.8, 132.2, 131.5, 130.8, 130.6, 129.7, 129.3, 129.2, 129.0, 128.9, 116.7, 53.3. 19 19F NMR (564.9 MHz, CD3CN): δ - 158.8 to - 159.0. HRMS (ESI): Calcd for C 22 H 19 BF2NO [M + H] + : 362.1522; found: 362.1531.

[0037] The reaction formula is as follows:

[0038]

[0039] Example 2

[0040] Using cyclohexylamine 2b to replace 2a in Example 1, and the remaining operation steps are the same as in Example 1, a yellow solid 5b was separated with a yield of 89%, Z / E = 89:11.

[0041] 11H NMR (600 MHz, CDCl3): δ 7.56 (d, J = 8.7 Hz, 2H), 7.40 - 7.37 (m, 4H), 7.28 - 7.26 (m, 2H), 7.22 - 7.19 (m, 2H), 7.05 (s, 1H), 3.08 - 3.01 (m, 1H), 1.70 - 1.68 (m, 2H), 1.60 - 1.57 (m, 2H), 1.44 - 1.42 (m, 1H), 1.17 - 1.11 (m, 2H), 1.04 - 0.97 (m, 1H), 0.72 - 0.65 (m, 2H). 13 13C NMR (100 MHz, CDCl3): δ 187.5, 135.4, 132.6, 132.3, 131.2, 130.6, 129.2, 128.4, 128.1, 113.6, 55.0, 33.3, 24.8, 24.6. 19 19F NMR (376.6 MHz, CDCl3): δ -161.6 to -161.8. HRMS (ESI): Calcd for C 21 H 22 BF2NONa [M + Na] + : 376.1655; found: 376.1663.

[0042] The reaction formula is as follows:

[0043]

[0044] Example 3

[0045] Using propargylamine 2c to replace 2a in Example 1, with the remaining operation steps the same as in Example 1, a yellow solid 5c was obtained by separation, with a yield of 55%, E / Z = 20:80.

[0046] 1 1H NMR (600 MHz, CDCl3): δ 7.63 (d, J = 8.3 Hz, 2H), 7.48 - 7.44 (m, 3H), 7.41 (t, J = 7.5 Hz, 1H), 7.27 - 7.24 (m, 2H), 7.15 (d, J = 6.8 Hz, 2H), 6.71 (s, 1H), 4.52 (dd, J = 5.8, 2.6 Hz, 2H), 2.42 (t, J = 2.6 Hz, 1H). 13 13C NMR (150 MHz, CDCl3): δ 186.8, 133.4, 131.4, 131.0, 130.8, 130.3, 130.2, 128.8, 128.3, 115.5, 77.0, 75.1, 38.3. 19FNMR(564.9MHz,CDCl3):δ - 161.9 to - 162.1.HRMS(ESI):Calcd for C 18 H 14 BF2NONa [M+Na] + : 332.1029;found: 332.1034.

[0047] The reaction formula is as follows:

[0048]

[0049] Example 4

[0050] Replace 2a in Example 1 with 0.2 mmol of glycine methyl ester 2d, stir at 37 °C for 36 hours until 1a completely disappears, and the remaining operation steps are the same as those in Example 1. A yellow solid 5d is obtained by separation, with a yield of 44%, E / Z > 95:5.

[0051] 1 H NMR(400MHz,CDCl3):δ 7.66(d,J = 8.5Hz,2H),7.49 - 7.40(m,4H),7.28 - 7.25(m,2H),7.19 - 7.16(m,3H),4.53(d,J = 5.6Hz,2H),3.80(s,3H). 13 C NMR(100MHz,CDCl3):δ 187.0,169.2,133.4,131.4,130.9,130.8,130.2,130.1,128.8,128.3,115.9,53.0,48.4. 19 F NMR(376.6MHz,CDCl3):δ - 162.9 to - 163.2.HRMS(ESI):Calcd for C 18 H 17 BF2NO3 [M+H] + : 344.1264;found: 344.1274.

[0052] The reaction formula is as follows:

[0053]

[0054] Example 5

[0055] Replace 2a in Example 1 with p - methoxyaniline 2e, and the remaining operation steps are the same as those in Example 1. An orange solid 5e is obtained by separation, with a yield of 50%, E / Z > 95:5.

[0056] 11H NMR (400 MHz, CDCl3): δ 8.17 (s, 1H), 7.67 (d, J = 8.5 Hz, 2H), 7.57 - 7.49 (m, 6H), 7.30 - 7.25 (m, 4H), 6.92 (d, J = 9.1 Hz, 2H), 3.82 (s, 3H). 13 13C NMR (100 MHz, CDCl3): δ 185.6, 158.8, 133.3, 131.8, 131.6, 131.0, 130.78, 130.76, 130.4, 129.1, 128.3, 122.1, 118.0, 114.9, 55.7. 19 19F NMR (376.6 MHz, CDCl3): δ -158.3 to -158.5. HRMS (ESI): Calcd for C 22 H 19 BF2NO2 [M + H] + : 378.1471; found: 378.1476.

[0057] The reaction formula is as follows:

[0058]

[0059] Example 6

[0060] Using morpholinoaniline 2f to replace 2a in Example 1, stirring at 37 °C for 18 hours until 1a completely disappeared, and the remaining operation steps were the same as those in Example 1. A red solid 5f was obtained by separation, with a yield of 40%, E / Z = 88:12.

[0061] 1 1H NMR (400 MHz, CDCl3): δ 8.17 (s, 1H), 7.65 (d, J = 8.5 Hz, 2H), 7.55 - 7.43 (m, 6H), 7.29 - 7.24 (m, 4H), 6.89 (d, J = 9.1 Hz, 2H), 3.85 (t, J = 4.9 Hz, 4H), 3.17 (t, J = 4.9 Hz, 4H). 13 13C NMR (100 MHz, CDCl3): δ 185.0, 150.4, 133.2, 131.6, 131.0, 130.8, 130.7, 130.4, 129.1, 128.3, 124.0, 121.6, 118.1, 116.0, 66.9, 48.9. 19 19F NMR (376.6 MHz, CDCl3): δ -158.2 to -158.5. HRMS (ESI): Calcd for C 25 H 23BF2N2O2Na[M+Na] + : 455.1713; found: 455.1719.

[0062] The reaction equation is as follows:

[0063]

[0064] Example 7

[0065] Replace 2a in Example 1 with 2 g of aniline, stir at 37 °C for 12 hours until 1a completely disappears, replace potassium bifluoride in Example 1 with hexafluoroisopropanol, and the remaining operation steps are the same as in Example 1. 5 g of yellow solid is separated, with a yield of 69%, E / Z > 95:5.

[0066] 1 H NMR (400 MHz, CDCl3): δ 8.17 (s, 1H), 7.67 (d, J = 8.6 Hz, 2H), 7.56 - 7.46 (m, 6H), 7.42 - 7.38 (m, 2H), 7.30 - 7.25 (m, 5H). 13 C NMR (100 MHz, CDCl3): δ 186.9, 138.5, 133.6, 131.4, 131.0, 130.8, 130.7, 130.5, 129.8, 129.2, 129.0, 128.4, 127.3, 120.4. 19 F NMR (376.6 MHz, CDCl3): δ -158.5 to -158.8. HRMS (ESI): Calcd for C 21 H 16 BF2NONa[M+Na] + : 370.1185; found: 370.1193.

[0067] The reaction equation is as follows:

[0068]

[0069] Example 8

[0070] Replace 1a in Example 1 with potassium fluoroborate of p-methoxyphenylpropynone 1b, and the remaining operation steps are the same as in Example 1. 5 h of yellow solid is separated, with a yield of 80%, E / Z > 95:5.

[0071] 11H NMR (600 MHz, CDCl3): δ 7.64 (d, J = 9.1 Hz, 2H), 7.44 - 7.41 (m, 2H), 7.38 - 7.31 (m, 6H), 7.14 (d, J = 8.3 Hz, 2H), 6.75 (d, J = 9.1 Hz, 2H), 6.73 (s, 1H), 4.86 (d, J = 6.5 Hz, 2H), 3.80 (s, 3H).

[0072] 13 13C NMR (150 MHz, CDCl3): δ 184.6, 163.7, 135.8, 133.0, 131.7, 130.4, 130.1, 129.2, 128.6, 128.5, 128.4, 124.0, 114.3, 113.7, 55.5, 53.1. 19 19F NMR (564.9 MHz, CDCl3): δ -159.6 to -159.8. HRMS (ESI): Calcd for C 23 H 20 BF2NO2Na [M + Na] + : 414.1447; found: 414.1456.

[0073] The reaction formula is as follows:

[0074]

[0075] Example 9

[0076] Using potassium fluoroborate of p - bromophenyl propargyl ketone 1c to replace 1a in Example 1, stir at 37 °C for 6 hours until 1c completely disappears. The remaining operation steps are the same as those in Example 1. A yellow solid 5i is obtained by separation, with a yield of 82%, E / Z > 95:5.

[0077] 1 1H NMR (400 MHz, CDCl3): δ 7.49 (d, J = 8.8 Hz, 2H), 7.45 - 7.34 (m, 10H), 7.10 (d, J = 6.5 Hz, 2H), 6.95 (s, 1H), 4.89 (d, J = 6.5 Hz, 2H). 13 13C NMR (100 MHz, CDCl3): δ 183.9, 135.2, 131.9, 131.7, 130.8, 130.5, 130.3, 130.2, 129.3, 128.9, 128.8, 128.5, 128.2, 115.5, 53.4. 1919F NMR (376.6 MHz, CDCl3): δ -160.0 to -160.3. HRMS (ESI): Calcd for C 22 H 17 B 79 BrF2NONa [M+Na] + : 462.0447; found: 462.0447.

[0078] The reaction formula is as follows:

[0079]

[0080] Example 10

[0081] Using potassium fluoroborate of p-trifluoromethylphenylpropynone 1d to replace 1a in Example 1, stir at 37 °C for 12 hours until 1d completely disappears. The remaining operation steps are the same as those in Example 1. A yellow solid 5j is obtained by separation, with a yield of 70%, E / Z = 77:23.

[0082] 1 1H NMR (400 MHz, CDCl3): δ 7.73 (d, J = 8.5 Hz, 2H), 7.53 (d, J = 8.5 Hz, 2H), 7.45 - 7.35 (m, 8H), 7.11 (d, J = 8.1 Hz, 2H), 7.07 (s, 1H), 4.92 (d, J = 6.5 Hz, 2H). 13 13C NMR (100 MHz, CDCl3): δ 183.3, 135.0, 134.1, 133.8, 130.7, 130.4, 130.2, 129.3, 129.0, 128.9, 128.6, 125.2 (q, J CF = 3.8 Hz), 125.0, 122.3, 116.1, 53.6. 19 19F NMR (376.6 MHz, CDCl3): δ -63.2, -160.1 to -160.4. HRMS (ESI): Calcd for C 23 H 17 BF5NONa [M+Na] + : 452.1216; found: 452.1225.

[0083] The reaction formula is as follows:

[0084]

[0085] Example 11

[0086] Replace 1a in Example 1 with potassium 4-cyanophenylpropynone difluoroborate 1e, adjust the amount of benzylamine 1a to 0.15 mmol, stir at 37 °C for 3 hours until 1e completely disappears, and the remaining operation steps are the same as in Example 1. A yellow solid 5k is obtained by separation, with a yield of 68%, E / Z = 80:20.

[0087] 1 H NMR(400MHz,CDCl3):δ7.71(d,J=8.8Hz,2H),7.55(d,J=8.8Hz,2H),7.46-7.35(m,8H),7.13(s,1H),7.09(dd,J=8.0,1.9Hz,2H),4.92(d,J=6.5Hz,2H). 13 C NMR(100MHz,CDCl3):δ182.3,135.7,134.8,131.9,130.7,130.5,130.1,130.0,129.4,129.2,129.0,128.6,118.0,116.5,115.8,53.7. 19 F NMR(376.6MHz,CDCl3):δ-160.1to-160.3.HRMS(ESI):Calcd for C 23 H 18 BF2N2O[M+H] + :387.1475;found:387.1480.

[0088] The reaction formula is as follows:

[0089]

[0090] Example 12

[0091] Replace 1a in Example 1 with potassium naphthylpropynone difluoroborate 1f, and replace potassium bifluoride in Example 1 with hexafluoroisopropanol. The remaining operation steps are the same as in Example 1. A yellow solid 5l is obtained by separation, with a yield of 83%, E / Z > 95:5.

[0092] 1 H NMR(600MHz,CDCl3):δ8.32(s,1H),7.78(d,J=8.3Hz,1H),7.71(d,J=8.3Hz,1H),7.66(d,J=8.8Hz,1H),7.57-7.54(m,2H),7.48-7.33(m,9H),7.17(d,J=8.3Hz,2H),6.93(s,1H),4.93(d,J=6.4Hz,2H). 1313C NMR(150MHz,CDCl3):δ185.2,135.5,135.4,132.8,132.4,131.3,130.4,130.2,129.8,129.3,129.0,128.83,128.76,128.7,128.5,127.8,127.7,126.8,125.9,115.6,53.4. 19 19F NMR(564.9MHz,CDCl3):δ - 159.9 to - 160.1. HRMS(ESI): Calcd for C 26 H 20 BF2NONa [M + Na] + : 434.1498; found: 434.1507.

[0093] The reaction formula is as follows:

[0094]

[0095] Example 13

[0096] Replace 1 g of potassium fluoroborate of pyrenyl alkynone with 1a in Example 1, replace the water in Example 1 with a mixed solvent of water and acetonitrile (5:1), stir at 37 °C for 18 hours until 1 g completely disappears, and the remaining operation steps are the same as those in Example 1. An orange solid 5m is obtained by separation, with a yield of 54%, and E / Z > 95:5.

[0097] 1 1H NMR(600MHz,CDCl3):δ8.72(d,J = 9.2Hz,1H),8.25 - 8.22(m,2H),8.14(d,J = 9.4Hz,2H),8.04(t,J = 7.6Hz,1H),7.99(d,J = 8.8Hz,1H),7.92(d,J = 8.0Hz,1H),7.84(d,J = 7.9Hz,1H),7.47 - 7.42(m,4H),7.39 - 7.34(m,2H),7.19 - 7.14(m,3H),6.95(d,J = 6.5Hz,2H),5.02(d,J = 6.3Hz,2H). 1313C NMR (150 MHz, CDCl3): δ 189.9, 135.4, 133.7, 131.1, 131.0, 130.7, 130.4, 129.70, 129.66, 129.3, 129.1, 128.8, 128.6, 128.4, 127.9, 127.3, 126.5, 126.42, 126.36, 126.2, 125.4, 124.8, 124.3, 123.8, 117.7, 109.1, 53.5. 19 19F NMR (564.9 MHz, CDCl3): δ -159.6 to -159.8. HRMS (ESI): Calcd for C 32 H 22 BF2NONa [M+Na] + : 508.1655; found: 508.1661.

[0098] The reaction formula is as follows:

[0099]

[0100] Example 14

[0101] Using potassium thiophenylethynyltrifluoroborate 1h to replace 1a in Example 1, stirring at 37 °C for 8 hours until 1h completely disappeared, using hexafluoroisopropanol to replace potassium bifluoride in Example 1, and the remaining operation steps were the same as those in Example 1. A yellow solid 5n was obtained by separation, with a yield of 77%, E / Z > 95:5.

[0102] 1 1H NMR (400 MHz, CDCl3): δ 7.59 (dd, J = 4.9, 1.3 Hz, 1H), 7.50 - 7.43 (m, 4H), 7.38 - 7.30 (m, 5H), 7.24 - 7.21 (m, 2H), 7.00 (dd, J = 4.9, 3.9 Hz, 1H), 6.61 (s, 1H), 4.86 (d, J = 6.5 Hz, 2H). 13 13C NMR (100 MHz, CDCl3): δ 178.5, 135.7, 135.3, 135.24, 135.19, 131.2, 130.4, 130.2, 129.3, 129.2, 128.7, 128.5, 128.2, 114.1, 53.2. 19 19F NMR (376.6 MHz, CDCl3): δ -158.9 to -159.2. HRMS (ESI): Calcd for C 20 H 17 BF2NOS [M+H] +: 368.1086; found: 368.1096.

[0103] The reaction formula is as follows:

[0104]

[0105] Example 15

[0106] Replace 1a in Example 1 with potassium benzothienylpropynone tetrafluoroborate 1i, stir at 37 °C for 5 hours until 1i completely disappears, and the remaining operation steps are the same as those in Example 1. A yellow solid 5o is obtained by separation, with a yield of 79%, E / Z = 80:20.

[0107] 1 H NMR (400 MHz, CDCl3): δ 7.81 (s, 1H), 7.73 (d, J = 7.9 Hz, 2H), 7.52 - 7.49 (m, 3H), 7.41 - 7.31 (m, 7H), 7.28 - 7.25 (m, 2H), 6.77 (s, 1H), 4.89 (d, J = 6.5 Hz, 2H). 13 C NMR (100 MHz, CDCl3): δ 178.7, 143.5, 138.4, 135.4, 134.6, 132.7, 131.2, 130.2, 129.9, 129.5, 129.2, 128.7, 128.5, 127.6, 125.9, 125.1, 122.6, 115.5, 53.4. 19 F NMR (376.6 MHz, CDCl3): δ -159.0 to -159.2. HRMS (ESI): Calcd for C 24 H 18 BF2NOSNa [M+Na] + : 440.1062; found: 440.1069.

[0108] The reaction formula is as follows:

[0109]

[0110] Example 16

[0111] Replace 1a in Example 1 with potassium styrylpropynone tetrafluoroborate 1j, replace 2a in Example 1 with propargylamine 2c, and replace CsF in Example 1 with tetrabutylammonium difluorotriphenylsilicate (TBAT). Stir at 37 °C for 18 hours until 1j completely disappears, and the remaining operation steps are the same as those in Example 1. An orange solid 5p is obtained by separation, with a yield of 45%, E / Z = 88:12.

[0112] 11H NMR (400 MHz, CDCl3): δ 8.01 (d, J = 15.7 Hz, 1H), 7.54 - 7.42 (m, 5H), 7.39 - 7.34 (m, 3H), 7.23 (d, J = 8.4 Hz, 2H), 6.80 (d, J = 15.7 Hz, 2H), 4.53 (dd, J = 5.8, 2.6 Hz, 2H), 2.44 (t, J = 2.6 Hz, 1H). 13 13C NMR (100 MHz, CDCl3): δ 184.5, 146.2, 134.8, 131.2, 130.0, 129.9, 129.8, 129.7, 129.1, 129.0, 128.6, 116.6, 77.1, 75.1, 38.4. 19 19F NMR (376.6 MHz, CDCl3): δ -161.0 to -161.3. HRMS (ESI): Calcd for C 20 H 16 BF2NONa [M + Na] + : 358.1185; found: 358.1195.

[0113] The reaction formula is as follows:

[0114]

[0115] Example 17

[0116] Using naphthylphenylethyne precursor 4b to replace 4a in Example 1, and the remaining operation steps are the same as in Example 1, a yellow solid 5q was isolated with a yield of 75%, E / Z > 95:5.

[0117] 1 1H NMR (600 MHz, CDCl3): δ 7.87 (t, J = 7.6 Hz, 2H), 7.79 (d, J = 6.9 Hz, 1H), 7.69 (d, J = 8.6 Hz, 2H), 7.65 (s, 1H), 7.55 - 7.51 (m, 2H), 7.43 (t, J = 7.4 Hz, 1H), 7.37 - 7.35 (m, 4H), 7.33 - 7.30 (m, 1H), 7.23 (t, J = 7.9 Hz, 2H), 7.17 (d, J = 8.4 Hz, 1H), 6.98 (s, 1H), 4.91 (d, J = 6.4 Hz, 2H). 1313C NMR (150 MHz, CDCl3): δ 185.5, 135.4, 134.0, 133.1, 133.0, 131.7, 130.7, 130.1, 129.2, 129.1, 128.7, 128.5, 128.3, 128.1, 128.0, 127.0, 126.9, 115.1, 53.4. 19 19F NMR (564.9 MHz, CDCl3): δ -159.9 to -160.1. HRMS (ESI): Calcd for C 26 H 20 BF2NONa [M+Na] + : 434.1498; found: 434.1504.

[0118] The reaction formula is as follows:

[0119]

[0120] Example 18

[0121] Using 4,5-dimethoxyphenylacetylene precursor 4c to replace 4a in Example 1, and the remaining operation steps are the same as in Example 1, a yellow solid 5r was obtained by separation, with a yield of 57%, E / Z > 95:5.

[0122] 1 1H NMR (600 MHz, CDCl3): δ 7.69 (d, J = 8.6 Hz, 2H), 7.45 (t, J = 7.4 Hz, 1H), 7.39 - 7.32 (m, 5H), 7.29 - 7.26 (m, 2H), 6.98 (s, 1H), 6.89 (d, J = 8.2 Hz, 1H), 6.69 (dd, J = 8.2, 2.0 Hz, 1H), 6.56 (d, J = 2.0 Hz, 1H), 4.89 (d, J = 6.4 Hz, 2H), 3.87 (s, 3H), 3.69 (s, 3H). 13 13C NMR (100 MHz, CDCl3): δ 184.9, 150.2, 149.2, 135.5, 133.0, 131.7, 130.6, 129.2, 128.7, 128.5, 128.3, 123.3, 122.5, 115.2, 113.1, 112.4, 56.02, 55.97, 53.3. 19 19F NMR (376.6 MHz, CDCl3): δ -160.4 to -160.6. HRMS (ESI): Calcd for C 24 H 22 BF2NO3Na [M+Na] +: 444.1553; found: 444.1558.

[0123] The reaction formula is as follows:

[0124]

[0125] Example 19

[0126] Using the benzyne precursor 4d derived from 1,3 - benzodioxole to replace 4a in Example 1, and using tetrabutylammonium difluorotriphenylsilicate (TBAT) to replace CsF in Example 1, with the remaining operation steps the same as in Example 1, a yellow solid 5s was obtained by separation, with a yield of 60%, E / Z = 93:7.

[0127] 1 H NMR (400 MHz, CDCl3): δ 7.70 (d, J = 8.4 Hz, 2H), 7.46 (t, J = 7.4 Hz, 1H), 7.40 - 7.28 (m, 7H), 6.88 (s, 1H), 6.85 (d, J = 7.9 Hz, 1H), 6.58 (dd, J = 7.9, 1.7 Hz, 1H), 6.55 (d, J = 1.6 Hz, 1H), 5.99 (s, 2H), 4.89 (d, J = 6.4 Hz, 2H). 13 C NMR (100 MHz, CDCl3): δ 185.3, 149.1, 148.0, 135.4, 133.1, 131.6, 130.7, 129.3, 128.8, 128.6, 128.3, 124.4, 123.7, 114.9, 110.5, 109.9, 101.6, 53.3. 19 F NMR (376.6 MHz, CDCl3): δ - 160.4 to - 160.6. HRMS (ESI): Calcd for C 23 H 18 BF2NO3Na [M + Na] + : 428.1240; found: 428.1246.

[0128] The reaction formula is as follows:

[0129]

[0130] Example 20

[0131] Using the benzyne precursor 4e derived from 1,3 - benzocyclopentene to replace 4a in Example 1, with the remaining operation steps the same as in Example 1, a yellow solid 5t was obtained by separation, with a yield of 75%, E / Z > 95:5.

[0132] 11H NMR (400 MHz, CDCl3): δ 7.69 (d, J = 8.5 Hz, 2H), 7.44 (t, J = 7.4 Hz, 1H), 7.40 - 7.33 (m, 5H), 7.28 (d, J = 8.4 Hz, 2H), 7.24 (d, J = 8.6 Hz, 1H), 6.95 (s, 1H), 6.91 - 6.85 (m, 2H), 4.89 (d, J = 6.4 Hz, 2H), 2.92 (t, J = 7.5 Hz, 2H), 2.86 (t, J = 7.5 Hz, 2H), 2.09 (hept, J = 7.5 Hz, 2H). 13 13C NMR (100 MHz, CDCl3): δ 185.0, 146.3, 144.9, 135.6, 132.9, 131.8, 130.7, 129.2, 128.7, 128.6, 128.5, 128.2, 128.0, 126.1, 126.0, 115.8, 53.2, 33.0, 32.8, 25.4. 19 19F NMR (376.6 MHz, CDCl3): δ -160.4 to -160.6. HRMS (ESI): Calcd for C 25 H 23 BF2NO [M + H] + : 402.1835; found: 402.1846.

[0133] The reaction formula is as follows:

[0134]

[0135] Example 21

[0136] Using 3,6 - dimethylbenzyne precursor 4f to replace 4a in Example 1, with the remaining operation steps the same as in Example 1, a white solid 5u was isolated, with a yield of 93%, E / Z > 95:5.

[0137] 1 1H NMR (400 MHz, CDCl3): δ 7.66 (d, J = 8.6 Hz, 2H), 7.45 (t, J = 7.4 Hz, 1H), 7.39 - 7.32 (m, 5H), 7.29 - 7.25 (m, 2H), 7.17 (d, J = 7.8 Hz, 1H), 7.11 (d, J = 7.8 Hz, 1H), 6.89 (s, 1H), 6.63 (s, 1H), 4.94 (dd, J = 14.6, 7.1 Hz, 1H), 4.83 (dd, J = 14.6, 6.0 Hz, 1H), 2.28 (s, 3H), 1.98 (s, 3H). 1313C NMR (100 MHz, CDCl3): δ 184.6, 137.1, 135.6, 134.7, 133.2, 132.0, 131.5, 131.3, 130.2, 130.1, 130.0, 129.2, 128.7, 128.4, 114.6, 53.3, 21.0, 19.2. 19 19F NMR (376.6 MHz, CDCl3): δ -160.5 to -160.7. HRMS (ESI): Calcd for C 24 H 23 BF2NO [M+H] + : 390.1835; found: 390.1840.

[0138] The reaction formula is as follows:

[0139]

[0140] Example 22 Derivatization transformation of the compound of the present invention

[0141] (1) Under an air atmosphere, weigh 5a (18.1 mg, 0.05 mmol) of the product of Example 1 into a 10 mL reaction tube and dissolve it in 0.6 mL of dichloromethane. While stirring at 0 °C, add BF3·Et2O (6 μL, 0.05 mmol). After 10 minutes, add TMSCN (31 μL, 0.25 mmol), and resume stirring at room temperature for 2 hours to obtain a crude product. Subsequently, add saturated aqueous sodium bicarbonate solution to the crude product for neutralization, and extract with dichloromethane. Combine the organic layers, wash with water, dry over anhydrous sodium sulfate, and filter, then concentrate under reduced pressure. Rapid separation and purification by column chromatography (ethyl acetate / n-hexane = 1:4) gives a yellow solid 6a with a yield of 96%, E / Z > 95:5, and a solid fluorescence quantum yield of 49.8%.

[0142] 1 1H NMR (400 MHz, CDCl3): δ 7.64 (d, J = 7.3 Hz, 2H), 7.50 - 7.35 (m, 9H), 7.31 - 7.27 (m, 2H), 7.14 (d, J = 6.4 Hz, 2H), 6.91 (s, 1H), 4.96 (d, J = 7.3 Hz, 2H). 13 13C NMR (100 MHz, CDCl3): δ 186.2, 134.7, 133.6, 130.9, 130.7, 130.4, 130.23, 130.19, 129.4, 129.1, 129.0, 128.54, 128.48, 116.4, 53.4. 1919F NMR (376.6 MHz, CDCl3): δ -180.3 to -180.6. HRMS (ESI): Calcd for C 23 H 18 BFN2ONa [M+Na] + : 391.1388; found: 391.1402.

[0143] Compared with 5a, the fluorescence emission wavelength of 6a shows a red shift, and the solid fluorescence quantum yield is significantly improved (49.8%), indicating that the conversion of B-F bond to B-CN bond will lead to significant changes in photophysical properties such as fluorescence quantum yield and emission wavelength.

[0144] (2) Under air atmosphere, weigh the product 5a (18.1 mg, 0.05 mmol) of Example 1 into a 10 mL reaction tube and dissolve it with 0.8 mL of methanol. Add potassium carbonate (15.2 mg, 0.11 mmol) and stir at room temperature for 2 hours. Concentrate the reaction solution, add water, and extract with dichloromethane. Combine the organic layers, wash with water, dry over anhydrous sodium sulfate, filter, and then concentrate under reduced pressure. Rapid column chromatography purification (ethyl acetate / n-hexane = 1:1) gives a light green solid 6b with a yield of 73%, E / Z > 95:5, and a solid fluorescence quantum yield of 73.6%. 1 1H NMR (400 MHz, CDCl3): δ 7.64 (d, J = 8.6 Hz, 2H), 7.44 - 7.30 (m, 9H), 7.28 - 7.24 (m, 2H), 7.11 (d, J = 8.1 Hz, 2H), 6.76 (s, 1H), 4.95 (d, J = 6.2 Hz, 2H), 3.48 (s, 6H). 13 13C NMR (100 MHz, CDCl3): δ 185.2, 136.6, 132.8, 132.3, 132.2, 130.5, 130.3, 129.9, 129.1, 128.5, 128.3, 128.11, 128.06, 115.7, 52.1, 50.2. HRMS (ESI): Calcd for C 24 H 24 BNO3Na [M+Na] + : 408.1741; found: 408.1751.

[0145] The above two reaction equations are as follows:

[0146]

[0147] Compared with 5a, the fluorescence emission wavelength of 6b shows a blue shift, and the solid fluorescence quantum yield is significantly improved (73.6%). This indicates that the conversion of B-F bonds into B-O bonds will cause significant changes in photophysical properties such as fluorescence quantum yield and emission wavelength.

[0148] Example 23 Aggregation-induced emission effect of the compounds of the present invention

[0149] The product 5a of Example 1 was dissolved in water / tetrahydrofuran mixed solutions with different volume fractions (the proportion of water was 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95% respectively), and the concentration was 10 μM. The fluorescence emission intensity (λ em = 492 nm) gradually increased with the increase of water content and increased rapidly at 80% water content. The experimental results show that compound 5a has the characteristic of aggregation-induced fluorescence enhancement.

[0150] Table 1 Photophysical properties of representative compounds

[0151]

[0152]

[0153] The experimental results show that tetrasubstituted boron oxacycle derivatives containing 1,2-distyryl structure (Serial Nos. 2-8) have a wide fluorescence range (472 - 541 nm) and good solid fluorescence quantum yields (14.7% - 73.6%), while the fluorescence efficiency of the trisubstituted boron oxacycle derivative (Serial No. 1) is significantly reduced (3.7%) when in the solid state.

Claims

1. A 3-imino-4,5-diarylboroxolium salt derivative, characterized in that, The structure is as follows: Among them, R 1 is a substituted phenyl or alkenyl, Ar is a substituted phenyl, R 2 is any substituent, and X is a halogen atom, a cyano group or an alkoxy group.

2. The preparation method of a 3-imino-4,5-diarylboroxolium salt derivative as claimed in claim 1, characterized in that The steps are as follows: 1) Mix potassium alkynone fluoroborate and organic amine, then add water, stir at 36 - 38 °C for 2 - 24 hours, then rotary evaporate to remove the solvent under reduced pressure at 30 - 50 °C, and after drying in a vacuum drying oven, obtain the crude product of 3-imino-5-arylboroxine; 2) In a glove box filled with high-purity argon, mix the above crude product with inorganic base and weak acid buffer, then add acetonitrile and 2-(trimethylsilyl)phenyl trifluoromethanesulfonate, stir vigorously at room temperature for 24 - 26 hours, then rotary evaporate to remove the solvent at 30 - 50 °C, separate the target product by column chromatography, and then recrystallize with a solvent to obtain the 3-imino-4,5-diarylboroxonium salt derivative.

3. The preparation method of a 3-imino-4,5-diarylboroxolium salt derivative according to claim 2, characterized in that, The molar ratio of raw materials is as follows: potassium alkynone fluoroborate: organic amine: 2-(trimethylsilyl)phenyl trifluoromethanesulfonate: inorganic base: weak acid buffer = 1:1.4 - 1.6:1.4 - 1.6:2.4 - 2.6:1.9 - 2.

1.

4. The preparation method of a 3-imino-4,5-diarylboroxolium salt derivative according to claim 3, characterized in that, The molar ratio of raw materials is as follows: potassium alkynone fluoroborate: organic amine: 2-(trimethylsilyl)phenyl trifluoromethanesulfonate: inorganic base: weak acid buffer = 1:1.5:1.5:2.5:

2.

5. The preparation method of a 3-imino-4,5-diarylboroxolium salt derivative according to claim 2, characterized in that, In step 1), the dosage ratio of water to potassium alkynone fluoroborate is 0.4 - 0.5 mL: 0.1 mmol; in step 2), the dosage ratio of acetonitrile to potassium alkynone fluoroborate is 0.8 - 0.9 mL: 0.1 mmol.

6. The preparation method of a 3-imino-4,5-diarylboroxolium salt derivative according to claim 2, characterized in that, The potassium alkynone fluoroborate is potassium alkynone fluoroborate containing any one of substituted phenyl, naphthyl, pyrenyl, 2-thienyl, 2-benzothienyl, styryl; The organic amine is any one of substituted benzylamine, alkylamine, propargylamine, α-amino acid ester, substituted aromatic amine; The 2-(trimethylsilyl)phenyl trifluoromethanesulfonate is a phenyl with 3,6-disubstitution, 4,5-disubstitution, 5-substitution or no substituent; 7. The preparation method of a 3-imino-4,5-diarylboroxolium salt derivative according to claim 2, characterized in that, The inorganic base is any one of cesium fluoride, potassium fluoride, sodium fluoride, ammonium fluoride, tetrabutylammonium fluoride, tetrabutylammonium difluorotriphenylsilicate, potassium carbonate, cesium carbonate; The weak acid buffer is any one of potassium bifluoride, hexafluoroisopropanol, trifluoroethanol, 18-crown-6; 8. The preparation method of a 3-imino-4,5-diarylboroxolium salt derivative according to claim 2, characterized in that, In step 2), column chromatography separation is carried out using a mixed solvent of ethyl acetate and n-hexane.

9. The preparation method of a 3-imino-4,5-diarylboroxolium salt derivative according to claim 2, characterized in that, The reaction yield of the preparation method is 40 - 93%, and the E / Z configuration ratio is 1:20 - 20:

1.

10. Use of the 3-imino-4,5-diarylboroxonium salt derivative obtained by the preparation method according to any one of claims 2 - 9 in the preparation of organic fluorescent materials.

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