2-pinacolboronic acid-9,9'-spirobis(xanthenes) and methods of synthesis thereof

Abstract

The application discloses 2-boronic acid pinacol ester-9,9'-spirobis(xanthene) and a synthesis method thereof, and belongs to the field of organic chemical synthesis. A structural formula of the 2-boronic acid pinacol ester-9,9'-spirobis(xanthene) is as follows: the 2-boronic acid pinacol ester-9,9'-spirobis(xanthene) is synthesized by the following method: 2-bromoxanthone is used as a starting material, reacts with phenol to synthesize 2-bromo-9,9'-spirobis(xanthene), and then is subjected to Suzuki-Miyaura reaction to synthesize. The synthesis method is simple in operation, low in production cost, and high in product content (greater than 99.9%); the synthesis method can meet the requirements of industrial production and application, is suitable for industrial production, and expands the application of spiro compounds as intermediates in the design and synthesis of organic optoelectronic functional materials.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of spiro compound and its synthesis method, especially 2-boronic acid pinacol ester-9,9'-spirobis (xanthene) and its synthesis method, belong to the field of organic chemical synthesis. BACKGROUND

[0002] Organic electroluminescent device has ultra-thin, simple structure, low energy consumption, fast response, full curing and active light emitting characteristics, and wide material selection range, low cost.Therefore, as a new generation of flat panel display technology, organic electroluminescent device shows broad application prospects in flat panel display and solid-state lighting fields, thereby attracting the attention of many researchers.

[0003] Spirobifluorene is a kind of sp 3 Hybrid carbon atom as center, cross-shaped geometry, perpendicular π system is conducive to inhibiting the accumulation of molecules, providing high solubility, easy to form amorphous phase trend, has higher thermal stability, steric hindrance effect, hole transport capacity and high bipolar carrier transport properties and other advantages in organic electronic field is widely used.The biggest difference between spirobis (xanthene) and spirobifluorene is that two fluorene units are replaced by xanthene, the introduction of oxygen atom can widen the band gap of material to a certain extent, so compared with spirobifluorene material, spirobis (xanthene) material has higher triplet energy level, also retains the advantages of good thermal stability of spirofluorene.

[0004] The compound 2-boronic acid pinacol ester-9,9'-spirobis (xanthene) of the present application is an important intermediate for the synthesis of organic optoelectronic functional materials. 2-Bromo xanthone is used as a starting material, reacted with phenol to synthesize 2-bromo-9,9'-spirobis (xanthene), and then subjected to Suzuki-Miyaura reaction to synthesize the target compound 2-boronic acid pinacol ester-9,9'-spirobis (xanthene). Currently, the target compound and the synthesis method have not been reported in related literature. SUMMARY

[0005] The present application aims to provide a new spiro compound-2-boronic acid pinacol ester-9,9'-spirobis (xanthene) and its synthesis method.

[0006] The specific technical solutions are as follows:

[0007] The structure of 2-boronic acid pinacol ester-9,9'-spirobis (xanthene) according to the present application is as follows:

[0008]

[0009] The synthesis route is as follows:

[0010]

[0011] The preparation method comprises the following steps:

[0012] (1) 2-bromoxanthone is used as a starting material, phenol is added, a solid acid catalyst is added, the reaction temperature and the reaction time are controlled, after the reaction is detected by HPLC, water washing, extraction, dispersion, filtration and drying are performed to obtain the compound 2-bromoxanthone.

[0013] (2) under an argon atmosphere, the compound 2-bromoxanthone, potassium acetate, bis(pinacolato)diboron, a catalyst 2-dicyclohexylphosphino-2',4',6'-triisopropyl-1,1'-biphenyl(2'-methylamino-1,1'-biphenyl-2-yl)palladium(II) (XPhos Pd G4) and methyltetrahydrofuran (MeTHF) are added as a solvent, the reaction temperature and the reaction time are controlled, after the reaction is detected by HPLC, water washing, extraction, dispersion, filtration and drying are performed to obtain the compound 2-boronic acid pinacol ester-9,9'-spirobis(xanthene), and the content is greater than 99.9%.

[0014] In the present application, in the step (1), the molar ratio of 2-bromoxanthone to phenol is 1.0:2.0-10.0, preferably 1.0:5.0; the reaction temperature is 80-150°C, preferably the reaction temperature is 110°C; and the reaction time is 24-72h, preferably the reaction time is 48h.

[0015] In the present application, in the step (1), the solid acid catalyst Zr(SO4)2 / ZnO is preferably used; the amount of Zr(SO4)2 / ZnO is 0.1%-5% of the molar mass of 2-bromoxanthone, preferably the amount is 1%.

[0016] In the present application, in the step (2), the molar ratio of 2-bromoxanthone to bis(pinacolato)diboron is 1.0:1.0-1.5, preferably 1.0:1.2; the molar ratio of 2-bromoxanthone to potassium acetate is 1.0:2.0-4.0, preferably 1.0:3.0; the reaction temperature is 80-100°C, preferably the reaction temperature is 100°C; and the reaction time is 10-24h, preferably the reaction time is 12h.

[0017] In the present application, in the step (2), the amount of XPhos Pd G4 is 0.1%-5% of the molar mass of 2-bromoxanthone, preferably the amount is 1%.

[0018] The application synthesizes compound 2-pinacol borate-9,9'-spirobis(xanthene) by taking 2-bromoxanthone as a starting material, has low production cost, simple operation, and can meet the needs of industrial production and application, and is suitable for industrial production.

[0019] Compared with the prior art, the application has the following advantages and beneficial effects:

[0020] 1. The novel spiro compound has novel structure, is connected by two xanthenes through sp3 hybrid carbon atoms, has a cross molecular configuration, has good thermal stability, and the introduction of oxygen atoms can widen the band gap of the material to some extent, so that the spirobis(xanthene) material has a higher triplet energy level compared with the spirobifluorene material, and can be used as an important intermediate of organic optoelectronic functional material.

[0021] 2. The spiro compound is synthesized by taking 2-bromoxanthone as a starting material and phenol as a raw material through one-pot reaction and Suzuki-Miyaura reaction, has mild reaction conditions, simple synthesis process, low production cost, and high product yield of more than 98%, and is suitable for industrial production.

[0022] 3. In the reaction process of synthesizing compound 2-bromo-9,9'-spirobis(xanthene), 2-bromoxanthone and phenol are used as raw materials, a solid acid is used as a catalyst, the solid acid catalyst has strong acidity, good thermal stability, high catalytic efficiency, less side reactions, and high yield of more than 83%. DETAILED DESCRIPTION

[0023] Figure 1 The TG curve of the compound 2-pinacol borate-9,9'-spirobis(xanthene) of the application is shown in the following figure. 1 H NMR spectrum;

[0024] Figure 2 The TG curve of the compound 2-pinacol borate-9,9'-spirobis(xanthene) of the application is shown in the following figure. 13 C NMR spectrum;

[0025] Figure 3 The TG curve of the compound 2-pinacol borate-9,9'-spirobis(xanthene) of the application is shown in the following figure.

[0026] Figure 4The DSC curve of the compound 2-boronate pinacol ester-9,9'-spirodi(oxanthracene) of the present invention is shown.

[0027] Figure 5 The UV curve of the compound 2-boronate pinacol ester-9,9'-spirodi(oxanthracene) of the present invention is shown.

[0028] Figure 6 The compound 2-boronate pinacol ester-9,9'-spirodi(oxanthracene) of this invention 1 H NMR spectrum;

[0029] Figure 7 The compound 2-boronate pinacol ester-9,9'-spirodi(oxanthracene) of this invention 13 C NMR spectrum; Specific implementation methods

[0030] To better illustrate the present invention, the following examples are provided:

[0031] Example 1:

[0032] Synthesis and characterization of intermediate 2-bromo-9,9'-spirodi(oxanthracene)

[0033] Add 41.3 g (150 mmol) of 2-bromothallone and 68 mL (ρ = 1.071 g / cm³) of phenol to a 500 mL round-bottom flask. -3 750 mmol) was added to Zr(SO4)2 / ZnO (54 mg, 1.5 mmol), and the reaction temperature was controlled at 110 °C for 48 h. After the reaction was completed by HPLC, water was added to quench the reaction, and the mixture was extracted three times with dichloromethane (50 mL × 3). The organic phase was washed with water, dried, filtered, and the solvent was recovered under reduced pressure. The mixture was then dispersed in methanol, filtered, and dried to obtain 2-bromo-9,9'-spirodi(oxanthracene), weighing 53.3 g, with a purity of 99.5% and a yield of 83.1%. The melting point was 188.34 °C. 1 H NMR (400MHz, CDCl3) δ (ppm): 7.27–7.24 (m, 1H, ArH), 7.21-7.12 (m, 6H, ArH), 7.06–7.04 (d, J = 8. 0Hz,1H,ArH),6.97–6.96(d,J=4.0Hz,1H,ArH),6.93–6.87(m,3H,ArH),6.86–6.83(m,3H,ArH);

[0034] 13C NMR (100 MHz, CDC13), δ (ppm): 149.08, 148.72, 148.39, 134.04, 131.56, 131.48, 131.24, 129.09, 128.78, 128.33, 128.16, 124.07, 123.91, 118.19, 116.42, 116.19, 115.82, 42.53.

[0035] Synthesis and characterization of target compound 2-boronic acid pinacol ester-9,9'- spirobi(xanthenes)

[0036] Into a 500 mL three-necked flask, 2-bromo-9,9'-spirobi(xanthenes) (42.7 g, 100 mmol), potassium acetate (29.4 g, 300 mmol), 150 mL methyltetrahydrofuran (MeTHF) and bis(pinacolato)diboron (30.5 g, 120 mmol) were added under argon atmosphere. Catalyst XPhos Pd G4 (0.8 g, 1 mmol) was added. The reaction temperature was controlled at 100 °C for 12 h. After the reaction was completed by HPLC detection, water was added for quenching, dichloromethane (50 mL x 3) was used for extraction for three times, the organic phase was washed with water, dried, filtered, and the solvent was recovered under reduced pressure. The compound 2-boronic acid pinacol ester-9,9'-spirobi(xanthenes) was obtained by dispersion with methanol, filtration and drying. The weight was 46.7 g, the yield was 98.4%, and the content was 99.9%. The melting point was 255.29 °C;

[0037] 1 H NMR (400 MHz, CDC13), δ (ppm): 7.74 (dd, J = 8.0, 1.6 Hz, 1H, ArH), 7.39 (d, J = 1.6 Hz, 1H, ArH), 7.25-7.21 (m, 5H, ArH), 7.20-7.17 (m, 2H, ArH), 6.98-6.89 (m, 6H, ArH), 1.29 (s, 12H, -CH3);

[0038] 13 C NMR (100 MHz, CDC13), δ (ppm): 152.22, 149.17, 148.03, 138.66, 134.85, 131.58, 131.28, 130.42, 129.49, 128.24, 127.84, 127.75, 123.85, 123.65, 116.16, 116.15, 115.55, 83.62, 42.31, 24.79.

[0039] MS (EI, m / z): Calcd for C 31 H 27 BO4[M] + 474.36, found 474.54.。

Claims

1. A method for synthesizing 2-boronic acid pinacol ester-9,9'-spirobis(xanthenes) of the molecular structure, characterized in that, The method is as follows: (1) 2-bromoxanthone is used as a starting material, phenol is added, solid acid catalysis is added, the reaction temperature and the reaction time are controlled, the reaction is detected by HPLC after the reaction is completed, and then water washing, extraction, dispersion, filtration and drying are performed to obtain 2-bromo-9,9'-spirobis(xanthene); the solid acid is selected from Zr(SO4)2 / ZnO; (2) under an argon atmosphere, compound 2-bromo-9,9'-spirobis(xanthene), potassium acetate, bis(pinacolato)diboron, a catalyst 2-dicyclohexylphosphino-2',4',6'-triisopropyl-1,1'-biphenyl(2'-methylamino-1,1'-biphenyl-2-yl)palladium(II) (XPhos Pd G4) are added, methyltetrahydrofuran is used as a solvent, the reaction temperature and the reaction time are controlled, the reaction is detected by HPLC after the reaction is completed, and then water washing, extraction, dispersion, filtration and drying are performed to obtain 2-boronic acid pinacol ester-9,9'-spirobis(xanthene).

2. The method of synthesizing 2-pinacolboronic acid-9,9'-spirobis(thioxanthene) according to claim 1, wherein, In step (1), the molar ratio of 2-bromoxanthone to phenol is 1.0:2.0-10.0; the reaction temperature is 80-150 DEG C; and the reaction time is 24-72 h.

3. The method of synthesizing 2-boronic acid pinacol ester-9,9'-spirobis(xanthenes) according to claim 1, characterized in that, In step (1), the amount of Zr(SO4)2 / ZnO is 0.1%-5% of the molar mass of 2-bromoxanthone.

4. The method of synthesizing 2-boronic acid pinacol ester-9,9'-spirobis(xanthenes) according to claim 1, characterized in that, In step (2), the molar ratio of 2-bromo-9,9'-spirobis(xanthene) to bis(pinacolato)diboron is 1.0:1.0-1.5; the molar ratio of 2-bromo-9,9'-spirobis(xanthene) to potassium acetate is 1.0:2.0-4.0; the reaction temperature is 80-100 DEG C; and the reaction time is 10-24 h.

5. The method of synthesizing 2-boronic acid pinacol ester-9,9'-spirobis(xanthenes) according to claim 1, wherein, In step (2), the amount of XPhos Pd G4 is 0.1%-5% of the molar mass of 2-bromo-9,9'-spirobis(xanthene).

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