Spiro(thianthrene-9,9'-oxathiene)-2'-boronic acid pinacol esters and methods of synthesis thereof

Abstract

This invention discloses a spiro(thioxanthracene-9,9'-oxoxanthracene)-2'-boronic acid pinacol ester and its synthetic method, belonging to the field of organic chemical synthesis. Its structural formula is as follows: This invention uses 2-bromothonone as a starting material, reacting it with benzenethiol to synthesize 2'-bromospiro(thioxanthracene-9,9'-oxoxanthracene), and then synthesizing the compound spiro(thioxanthracene-9,9'-oxoxanthracene)-2'-boronic acid pinacol ester via a Suzuki-Miyaura reaction. The synthetic method of this invention is simple to operate, has low production costs, and produces a product with a purity greater than 99.9%, meeting the needs of industrial production and application. It is suitable for industrial production and expands the application of spirocyclic compounds as intermediates in the design and synthesis of organic optoelectronic functional materials.

Description

Technical Field

[0001] This invention relates to a thiaspirocyclic compound and its synthesis method, and more particularly to a spiro(thiazanthracene-9,9′-oxazanthracene)-2′-boronic acid pinacol ester and its synthesis method, belonging to the field of organic chemical synthesis. Background Technology

[0002] Spirocyclic aromatic structural units possess large conjugated systems and rigid structures. Materials containing these units not only exhibit high thermal stability but also often display unique photophysical properties. Therefore, spirocyclic aromatic structural units have become an important structural unit in materials science research. Spiro(thioxanthracene-9,9′-oxanthracene)-2′-boronic acid pinacol ester contains spirocyclic aromatic structural units, oxanthracene, and thioxanthracene structural units. The introduction of oxygen and sulfur atoms can, to some extent, extend the band gap of the material, and it also exhibits good thermal stability and excellent photoelectric properties.

[0003] The target compound of this invention, spiro(thioxanthracene-9,9′-oxanthracene)-2′-boranoyl ester, is an important intermediate in the synthesis of organic optoelectronic functional materials. It is synthesized from 2-bromothonone as a starting material by reacting with benzenethiol to synthesize 2′-bromospiro(thioxanthracene-9,9′-oxanthracene), and then via a Suzuki-Miyaura reaction to synthesize the target compound, spiro(thioxanthracene-9,9′-oxanthracene)-2′-boranoyl ester. Currently, no relevant literature has reported on this target compound or its synthetic method. Summary of the Invention

[0004] The purpose of this invention is to provide a novel thiaspirocyclic compound—spiro(thiazanthracene-9,9′-oxazanthracene)-2′-boronic acid pinacol ester—and its synthesis method.

[0005] The specific technical solution is as follows:

[0006] The structural formula of the spiro(thioxanthracene-9,9′-oxanthracene)-2′-boronate pinacol ester described in this invention is as follows:

[0007]

[0008] Its synthetic route is as follows:

[0009]

[0010] Its preparation method includes the following steps:

[0011] (1) Under an argon atmosphere, 2-bromothonone was used as the starting material, and benzenethiol was added and mixed. Solid acid was added for catalysis, and the reaction temperature and reaction time were controlled. After the reaction was detected by HPLC, the compound 2′-bromospiro(thioxanthracene-9,9′-oxanthracene) was obtained by washing with water, extraction, dispersion, filtration and drying.

[0012] (2) Under an inert atmosphere, compound 2′-bromospiro(thioxanthracene-9,9′-oxanthracene), potassium acetate, and bis(pinacolyl)diboron were added to a catalyst of methanesulfonic acid (2-dicyclohexylphosphine-2′,4′,6′-triisopropyl-1,1′-biphenyl)(2′-methylamino-1,1′-biphenyl-2-yl)palladium(II) (XPhos Pd G4), with methyltetrahydrofuran (MeTHF) as the solvent. The reaction temperature and time were controlled. After the reaction was completed as detected by HPLC, the compound was obtained by washing with water, extraction, dispersion, filtration, and drying to obtain spiro(thioxanthracene-9,9′-oxanthracene)-2′-boronyl ester with a purity >99.9%.

[0013] In this invention, in step (1), the molar ratio of 2-bromo-toluene to benzyl mercaptan is 1.0:2.0 to 10.0, preferably 1.0:5.0; the reaction temperature is 120℃ to 180℃, preferably 160℃; and the reaction time is 48h to 72h, preferably 60h.

[0014] In this invention, in step (1), a solid acid catalyst Zr(SO4)2 / ZnO is preferably used; the amount of Zr(SO4)2 / ZnO is 0.1% to 5% of the molar mass of 2-bromo-toluene, preferably 1%;

[0015] In this invention, in step (2), the molar ratio of 2′-bromospiro(thioxanthracene-9,9′-oxazanthracene) to bis(pinacol)diboron is 1.0:1.0-1.5, preferably 1.0:1.2; the molar ratio of 2′-bromospiro(thioxanthracene-9,9′-oxazanthracene) to potassium acetate is 1.0:2.0-4.0, preferably 1.0:3.0; the reaction temperature is 80℃-100℃, preferably 100℃; the reaction time is 10h-24h, preferably 12h.

[0016] In this invention, in step (2), the catalyst preferably used is methanesulfonic acid (2-dicyclohexylphosphine-2′,4′,6′-triisopropyl-1,1′-biphenyl)(2′-methylamino-1,1′-biphenyl-2-yl)palladium(II) (XPhos Pd G4); the amount of XPhos Pd G4 is 0.1% to 5% of the molar mass of 2′-bromospiro(thioxanthracene-9,9′-oxanthracene), preferably 1%;

[0017] This invention synthesizes spiro(thioxanthracene-9,9′-oxanthracene)-2′-boronic acid pinacol ester using 2-bromoxanthone as a starting material. The production process is low-cost, simple, and yields a product with a purity greater than 99.9%, meeting the needs of industrial production and application. The obtained spiro(thioxanthracene-9,9′-oxanthracene)-2′-boronic acid pinacol ester has a melting point of 244.82℃ and a temperature of 345.63℃ at 18% weight loss, exhibiting excellent thermal stability and a high melting temperature. This expands the application of spiro(thioxanthracene-9,9′-oxanthracene)-2′-boronic acid pinacol ester as an intermediate in the design and synthesis of organic optoelectronic functional materials.

[0018] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0019] 1. The novel thiaspirocyclic compound of the present invention has a novel structure, consisting of oxanthracene and thiaspiraracene linked by sp3 hybridized carbon atoms in a cross-shaped molecular configuration. The introduction of oxygen and sulfur atoms can broaden the band gap of the material to a certain extent. Furthermore, it has good thermal stability and excellent photoelectric properties, and can be used as an important intermediate for organic optoelectronic functional materials.

[0020] 2. The novel thiaspirocyclic compound of the present invention is synthesized from 2-bromo-zanthonone as the starting material through a one-pot reaction and Suzuki-Miyaura reaction with benzenethiol to form the compound spiro(thiaxanthracene-9,9′-oxanthracene)-2′-boronic acid pinacol ester. The reaction conditions are mild, the synthesis process is simple, the production cost is low, and the product yield is high, reaching over 97%, making it suitable for industrial production.

[0021] 3. In the process of synthesizing compound 2-bromo-9,9'-spirodi(oxanthracene) in this invention, 2-bromo-toluene and benzenethiol are used as raw materials, and a solid acid is used as a catalyst. The solid acid catalyst has strong acidity, good thermal stability, high catalytic efficiency, fewer side reactions, and a high yield of over 72%. Attached Figure Description

[0022] Figure 1 TG-DSC spectrum of the target compound spiro(thioxanthracene-9,9′-oxanthracene)-2′-boronate pinacol ester;

[0023] Figure 2 UV spectrum of the target compound spiro(thioxanthracene-9,9′-oxanthracene)-2′-boronate pinacol ester;

[0024] Figure 3 The compound of this invention, spiro(thioxanthracene-9,9′-oxanthracene)-2′-boronate pinacol ester, is 1 H NMR spectrum;

[0025] Figure 4 The compound of this invention, spiro(thioxanthracene-9,9′-oxanthracene)-2′-boronate pinacol ester, is 13 C10 NMR spectrum. Specific implementation methods

[0026] To better illustrate the present invention, the following examples are provided:

[0027] Example 1:

[0028] Characterization data of the target compound spiro(thioxanthracene-9,9′-oxanthracene)-2′-boronate pinacol ester:

[0029] Under an argon atmosphere, 41.3 g (150 mmol) of 2-bromothallone and 77 mL (ρ = 1.078 g cm⁻¹) of benzyl mercaptan were added to a 500 mL round-bottom flask. -3 750 mmol) was added to Zr(SO4)2 / ZnO (54 mg, 1.5 mmol), the reaction temperature was controlled at 120 °C, and the reaction time was 72 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 compound 2′-bromospiro(thioxanthracene-9,9′-oxoxanthracene), weighing 48.2 g, with a yield of 72.6%.

[0030] Under an inert atmosphere, 44.3 g (100 mmol) of 2′-bromospiro(thioxanthracene-9,9′-oxazanthracene), 29.4 g (300 mmol) of potassium acetate, 150 mL of methyltetrahydrofuran (MeTHF), and 30.5 g (120 mmol) of bis(pinacol)diboron were added to a 500 mL three-necked flask. The catalyst, methanesulfonic acid (2-dicyclohexylphosphine-2′,4′,6′-triisopropyl-1,1′-biphenyl)(2′-methylamino-1,1′-biphenyl-2-yl)palladium(II) (XPhos Pd G4) (0.8 g, 1 mmol), was added. The reaction was carried out at 100℃ for 12 hours. After HPLC detection, the reaction was quenched with water, 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 the compound spiro(thioxanthracene-9,9′-oxanthracene)-2′-boronic acid pinacol ester, weighing 47.9 g, with a yield of 97.8% and a purity of 99.9%. The melting point was 244.82℃.

[0031] 1H NMR(400MHz,DMSO-d6)δ(ppm):7.55(dd,J=8.0,1.6Hz,1H,ArH),7.38(dd,J=8.0,1.6Hz,2H,ArH),7.25(d,J=8.4Hz,1H,ArH),7.22–7.12(m,5H,ArH),7.02(ddd,J=8.4,7.2,1.6Hz,2H,ArH),6.99–6.89(m,2H,ArH),6.74(dd,J=8.0,1.2Hz,2H,ArH),1.16(s,12H,-CH3);

[0032] 13 C NMR(100MHz,CDCl3)δ(ppm):151.71,146.68,140.59,138.96,134.88,133.54,131.27,130.73,129.42,128.08,127.89,126.49,126.21,124.86,123.95,116.23,115.47,83.64,47.35,24.81.

[0033] MS(EI,m / z):Calcd for C 31 H 27 BO3S[M] + 490.42,found 490.76。

Claims

1. A method for synthesizing spiro(thioxanthracene-9,9'-oxanthracene)-2'-boronate pinacol ester, characterized in that, This can be achieved through the following method: (1) Under an argon atmosphere, 2-bromothonone was used as the starting material, and benzenethiol was added and mixed. Solid acid Zr(SO4)2 / ZnO was added as a catalyst. The reaction temperature and reaction time were controlled. After the reaction was detected by HPLC, 2'-bromospiro(thioxanthracene-9,9'-oxazanthracene) was obtained by washing with water, extraction, dispersion, filtration and drying. (2) Under an argon atmosphere, compound 2'-bromospiro(thioxanthracene-9,9'-oxanthracene), potassium acetate, and bis(pinacolyl)diboron were mixed, and the catalyst methanesulfonic acid (2-dicyclohexylphosphine-2',4',6'-triisopropyl-1,1'-biphenyl)(2'-methylamino-1,1'-biphenyl-2-yl)palladium(II) (XPhos Pd G4) was added. Methyltetrahydrofuran was used as the solvent. The reaction temperature and reaction time were controlled. After the reaction was completed by HPLC, the product was washed with water, extracted, dispersed, filtered, and dried to obtain spiro(thioxanthracene-9,9'-oxanthracene)-2'-boronyl ester. The molecular structure of the spiro(thioxanthracene-9,9'-oxanthracene)-2'-boronate pinacol ester is as follows: 。 2. The method for synthesizing spiro(thioxanthracene-9,9'-oxanthracene)-2'-boronate pinacol ester as described in claim 1, characterized in that, In step (1), the reaction temperature is 120 ℃~180 ℃ and the reaction time is 48 h~72 h.

3. The method for synthesizing spiro(thioxanthracene-9,9'-oxanthracene)-2'-boronate pinacol ester as described in claim 1, characterized in that, In step (1), the amount of Zr(SO4)2 / ZnO used is 0.1% to 5% of the molar mass of 2-bromo-tonone.

4. The method for synthesizing spiro(thioxanthracene-9,9'-oxanthracene)-2'-boronate pinacol ester as described in claim 1, characterized in that, In step (2), the molar ratio of 2'-bromospiro(thioxanthracene-9,9'-oxazanthracene) to bis(pinacol)diboron is 1.0:1.0~1.5; the molar ratio of 2'-bromospiro(thioxanthracene-9,9'-oxazanthracene) to potassium acetate is 1.0:2.0~4.0; the reaction temperature is 80℃~100℃; and the reaction time is 10 h~24 h.

5. The method for synthesizing spiro(thioxanthracene-9,9'-oxanthracene)-2'-boronate pinacol ester as described in claim 1, characterized in that, In step (2), the amount of XPhos Pd G4 used is 0.1% to 5% of the molar mass of 2'-bromospiro(thioxanthracene-9,9'-oxanthracene).

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