Method for producing cyclopenta-fused polycyclic aromatic hydrocarbon compound
The hydrothermal synthesis of CP-PAHs using platinum, palladium, or iridium catalysts forms a five-membered ring structure, addressing the lack of a versatile synthesis method and enabling efficient production of CP-PAHs with enhanced ring structures.
Patent Information
- Application Number
- JP2024016836
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-02-07
- Publication Date
- 2025-08-20
AI Technical Summary
A versatile synthesis method for cyclopenta-fused polycyclic aromatic hydrocarbon compounds (CP-PAHs) has not been established, limiting their production and utilization in functional materials.
A method involving the reaction of a reaction substrate with platinum, palladium, or iridium catalysts under hydrothermal synthesis conditions forms a five-membered ring structure, converting benzo[c]phenanthrene into a cyclopenta-fused skeleton, exemplified by producing benzo[p]indeno[1,2,3,4-defg]chrysene from dibenzo[g,p]chrysene.
This method allows for the direct and quantitative synthesis of CP-PAHs with increased fused rings in a single step, overcoming the synthesis challenges of conventional methods.
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Abstract
Description
[Technical Field]
[0001] The present invention relates to a method for producing a cyclopenta-fused polycyclic aromatic hydrocarbon compound. [Background technology]
[0002] Polycyclic aromatic hydrocarbons (PAHs) are a group of hydrocarbons that contain multiple rings of a carbon atom skeleton with conjugated double bonds and exhibit aromaticity. Compounds that incorporate a five-membered ring into PAHs are called CP-PAHs (Cyclopenta-fused PAHs; cyclopenta-fused polycyclic aromatic hydrocarbon compounds). Because their structures are distorted from a planar structure, they are known to have electron-accepting properties and unique luminescent properties, making them promising functional materials. However, a versatile synthesis method for CP-PAHs has not yet been established.
[0003] As one method for synthesizing such CP-PAHs, for example, Non-Patent Document 1 describes that CP-PAHs containing antiaromatic pyracylenes in the key structure can be efficiently synthesized by the intramolecular oxidative C—H coupling reaction of tetracene derivatives. [Prior art documents] [Non-patent literature]
[0004] [Non-Patent Document 1] Chaokumen, Murata M., Sugano Y., Wakamiya A., Murata Y., Angew. Chem. Int. Ed., 54, 9308-9312 (2015). Summary of the Invention [Problem to be solved by the invention]
[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a novel method for producing a cyclopenta-fused polycyclic aromatic hydrocarbon compound. [Means for solving the problem]
[0006] The present inventors conducted extensive research to solve the above-mentioned problems and found that, as shown in the chemical formula below, when a compound having a benzo[c]phenanthrene skeleton (1) is reacted under hydrothermal synthesis conditions in the presence of a platinum catalyst, a single bond is formed between the opposing carbon atoms of the bent "C" shape of the benzo[c]phenanthrene skeleton, converting it into a five-membered fused skeleton represented by (2). This method has the excellent feature of forming a five-membered ring structure, which is difficult to synthesize directly using conventional methods, in a single step. By using this production method, for example, as shown in the chemical reaction formula below, it is possible to quantitatively obtain benzo[p]indeno[1,2,3,4-defg]chrysene, which has an increased number of fused rings, from dibenzo[g,p]chrysene. The present invention was made based on the above findings and provides the following: [ka]
[0007] (1) The present invention is a method for producing a cyclopenta-fused polycyclic aromatic hydrocarbon compound, characterized by reacting a reaction substrate having a structure represented by the following formula (1) as at least a partial structure with a catalyst comprising at least one compound selected from the group consisting of platinum compounds, palladium compounds, and iridium compounds under hydrothermal synthesis conditions to obtain a compound having a structure represented by the following formula (2) as at least a partial structure: [ka]
[0008] (2) The present invention also relates to the method of producing a catalyst according to (1), wherein the platinum compound is at least one selected from the group consisting of PtO2, Pt, PtCl2, K2[PtCl4], H2[PtCl6]·6H2O and Na2[PtCl6]·6H2O, the palladium compound is PdO, and the iridium compound is IrCl3.
[0009] (3) The present invention also provides the production method according to (1) or (2), wherein the temperature of the hydrothermal synthesis conditions is 150° C. or higher.
[0010] (4) The present invention also provides the production method according to any one of (1) to (3), wherein the amount of the platinum compound to be reacted is 10 mol % to 70 mol % relative to the reaction substrate.
[0011] (5) The present invention also provides the production method according to any one of (1) to (4), further comprising adding Fe2O3 as a promoter and subjecting the mixture to the above hydrothermal conditions. [Effects of the Invention]
[0012] According to the present invention, there is provided a method for producing a novel cyclopenta-fused polycyclic aromatic hydrocarbon compound. DETAILED DESCRIPTION OF THE INVENTION
[0013] Hereinafter, one embodiment of the method for producing a cyclopenta-fused polycyclic aromatic hydrocarbon compound (hereinafter also referred to as CP-PAH) of the present invention will be described. Note that the present invention is not limited to the following embodiment, and can be carried out by making appropriate modifications within the scope of the present invention.
[0014] The method for producing CP-PAH of the present invention is characterized in that a reaction substrate having a structure represented by the following formula (1) as at least a partial structure is reacted with a catalyst consisting of at least one compound selected from the group consisting of platinum compounds, palladium compounds, and iridium compounds under hydrothermal synthesis conditions to obtain a compound having a structure represented by the following formula (2) as at least a partial structure.
[0015] [ka]
[0016] The compound having the structure represented by formula (1) at least as a partial structure is not particularly limited, as long as it has the structure represented by formula (1) in its structure. Such a compound may be the compound represented by formula (1) itself, or a compound to which one or more rings are fused. According to the production method of the present invention, a single bond is formed between the opposing carbon atoms of the bent "C" shape of the skeleton represented by formula (1) in such a compound, and the skeleton is converted to a skeleton represented by formula (2) in which a five-membered ring is fused. Furthermore, the compound having the structure represented by formula (1) at least as a partial structure may have various substituents, but is preferably a hydrocarbon.
[0017] An example of a compound having the structure represented by formula (1) as at least a partial structure, i.e., a reaction substrate, is represented by the following chemical formula: However, the substrate in the present invention is not limited to these.
[0018] [ka]
[0019] These reaction substrates are converted into the following compounds newly fused with a five-membered ring by the production method of the present invention.
[0020] [ka]
[0021] In the present invention, the above-mentioned reaction substrate is reacted with a catalyst consisting of at least one selected from the group consisting of platinum compounds, palladium compounds, and iridium compounds under hydrothermal synthesis conditions. Examples of hydrothermal synthesis conditions include heating at 150°C or higher in the presence of water. To carry out the reaction under these conditions, water, the catalyst described below, and the reaction substrate are placed in a sealed container and heated in a sealed state. A preferred reaction temperature is approximately 150 to 300°C, and more preferably approximately 180 to 280°C. The reaction time is approximately 72 hours.
[0022] The catalyst used is at least one selected from the group consisting of platinum compounds, palladium compounds, and iridium compounds. When this catalyst is subjected to hydrothermal synthesis conditions together with the reaction substrate, it causes the reaction substrate to form a new fused ring consisting of a five-membered ring.
[0023] The platinum compound may be at least one selected from the group consisting of PtO2, Pt, PtCl2, K2[PtCl4], H2[PtCl6]·6H2O, and Na2[PtCl6]·6H2O. Of these, PtO2 is preferred.
[0024] Examples of palladium compounds include Pd, PdO, PdCl2, Pd(OCOCH3)2, and Pd / C. Among these, PdO is preferred. Examples of iridium compounds include Ir, IrO2, IrCl3, and Ir(OCOCH3). n Among these, IrCl3 is preferred.
[0025] The amount of catalyst used in the hydrothermal synthesis reaction is preferably about 10 mol % to 70 mol %, more preferably about 20 mol % to 40 mol %, relative to the number of moles of the reaction substrate.
[0026] In the hydrothermal synthesis reaction, a co-catalyst can be used in addition to the catalyst described above. The use of a co-catalyst can increase the yield of the target product in which a new five-membered ring is fused to the reaction substrate. A preferred example of such a co-catalyst is Fe2O3. The amount of the co-catalyst added is preferably about 10 mol % to 200 mol % relative to the number of moles of the reaction substrate, and more preferably about 100 mol %. [Example]
[0027] The present invention will be explained in more detail below by way of examples, but the present invention is not limited to these examples in any way.
[0028] [Synthesis of reaction substrates] The reaction substrate, a condensed polycyclic hydrocarbon, was synthesized using the method reported in I. Takahashi, M. Hayashi, T. Fujita, and J. Ichikawa Chem. Lett. 2016, 46, 392. An example is shown below. Reaction substrates not shown in the examples below can also be synthesized using similar procedures.
[0029] Synthesis of 1,4-bis{2-[(1,3-dioxolan-2-yl)methyl]phenyl}naphthalene (compound 1a) [ka]
[0030] A solution of 1,4-dibromonaphthalene (2 g, 7 mmol), 2-{2-[(1,3-dioxolan-2-yl)methyl]phenyl}-4,4,5,5-tetramethyl-1,3,2-dioxaborane (4.5 g, 15.2 mmol), 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (XPhos; 171 mg, 5 mol%), tris(dibensylideneacetone)dipalladium(0) (PdCl(dba); 163 mg, 2.5 mol%), and KPO (9.0 g, 42 mmol) in 1,4-dioxane (68 mL) and water (34 mL) was reacted overnight at 120 °C. The reaction mixture was extracted three times with ethyl acetate, and the organic phase was washed with saturated brine and then dried over sodium sulfate. After the solvent was distilled off under reduced pressure, the residue was purified by silica gel column chromatography (hexane:ethyl acetate=30:1) and then washed with ethyl acetate to obtain Compound 1a as a white solid (yield: 1.26 g, 40%). 1 H NMR(CDCl3,400MHz) δ(ppm) 2.71-2.84(m,4H),3.71-3.85(m,8H),4.90(t,J=5.2Hz,2H),7.37-7.32(m,6H),7.39(s,2H),7.41-7.48(m,4H),7.56(d,J=7.2Hz,2H).
[0031] Synthesis of 1,6-bis{2-[(1,3-dioxolan-2-yl)methyl]phenyl}naphthalene (compound 1b) [ka]
[0032] A solution of naphthalene-1,6-diylbis(trifluoromethanesulfonate) (2 g, 4.7 mmol), 2-{2-[(1,3-dioxolan-2-yl)methyl]phenyl}-4,4,5,5-tetramethyl-1,3,2-dioxaborane (2.86 g, 9.87 mmol), [1,1-bis(diphenylphosphino)ferrocene]palladium(II) dichloride dichloromethane adduct (PdCl(dppf)·CHCl; 179 mg, 0.22 mmol), and KPO (6.0 g, 28.2 mmol) in 1,4-dioxane (68 mL) and water (34 mL) was reacted overnight at 120 °C. The reaction mixture was extracted three times with ethyl acetate, and the organic phase was washed with saturated brine and then dried over sodium sulfate. After the solvent was distilled off under reduced pressure, the residue was purified by silica gel column chromatography (hexane:ethyl acetate=2:1) to obtain Compound 1b as a colorless oil (yield: 1.7 g, 81%). 1 H NMR(CDCl3,400 MHz) δ(ppm) 2.69-2.83(m,2H),3.00(d,J=5.4Hz,2H),3.68-3.88(m,8H),4.88(t,J=5.2Hz,1H),4.99(t,J=5 .0Hz,1H),7.29-7.39(m,8H),7.41-7.49(m,4H),7.54(dt,J=8.0,3.6Hz,2H),7.84-7.87(m,2H).
[0033] Synthesis of dibenzo[c,l]chrysene (compound 2a) [ka]
[0034] Dibenzo[c,l]chrysene (compound 2a) was synthesized using compound 1c, which was obtained using the same procedure as compound 1a, except that 1,5-dibromonaphthalene was used instead of 1,4-dibromonaphthalene as the starting material. Trifluoromethanesulfonic acid (TfOH; 31 mg, 0.22 mmol) was added to a hexafluoro-2-propanol (HFIP) solution (6.7 mL) of compound 1c (676 mg, 1.49 mmol) at 0 °C, followed by stirring at the same temperature for 15 minutes. The reaction was then terminated by the addition of phosphate buffer (pH 7). The resulting solution was extracted three times with dichloromethane, and the organic phase was washed with saturated saline and then dried over sodium sulfate. The solvent was removed under reduced pressure, followed by purification by GPC (developing solvent: chloroform) to obtain compound 2a (yield: 418.3 mg, 85%). 1 H NMR(CDCl3,400MHz) δ(ppm) 7.64-7.68(m,2H),7.69-7.73(m,2H),7.90-7.97(m,6H),8.05-8.07(m,2H),9.06(d,J=8.2Hz,2H),9.14(d,J=8.7Hz,2H).
[0035] Synthesis of benzo[s]picene (compound 2b) [ka]
[0036] Trifluoromethanesulfonic acid (TfOH; 11 mg, 0.07 mmol) was added to a solution of compound 1a (311 mg, 0.7 mmol) in hexafluoro-2-propanol (HFIP) (2.3 mL) at 0 °C, followed by stirring at the same temperature for 15 minutes. The reaction was then quenched by the addition of phosphate buffer (pH 7). The resulting solution was extracted three times with dichloromethane, and the organic phase was washed with saturated brine and then dried over sodium sulfate. The solvent was removed under reduced pressure, and the crude mixture was washed with ethanol. Purification by silica gel chromatography (hexane:dichloromethane = 2:1) afforded compound 2b as a white solid (yield 193 mg, 84%). 1H NMR(CDCl3,400MHz) δ(ppm) 7.61-7.71(m,6H),8.03-8.07(m,4H),8.65(d,J=9.1Hz,2H),8.97(q,J=3.3Hz,2H),9.02(d,J=8.6Hz,2H).
[0037] Synthesis of benzo[a]picene (compound 2c) [ka]
[0038] To a solution (2.3 mL) of compound 1b (322 mg, 0.7 mmol) in hexafluoro-2-propanol (HFIP), trifluoromethanesulfonic acid (TfOH; 11 mg, 0.07 mmol) was added at 0 °C. The mixture was stirred at the same temperature for 15 minutes, and then phosphate buffer (pH 7) was added to terminate the reaction. The resulting solution was extracted three times with dichloromethane, and the organic phase was washed with saturated saline and then dried over sodium sulfate. The solvent was removed under reduced pressure, and the residue was purified by GPC (developing solvent: 1,2-dichloroethane) and washed with ethanol to give compound 2c as a white solid (yield: 38.4 mg, 16%). 1 H NMR(CDCl3,400MHz) δ(ppm) 7.66-7.73(m,2H),7.74-7.79(m,2H),7.94(dd,J=14.5,8.6Hz,2H),8.03-8 .11(m,4H),8.84-8.94(m,4H),9.18(d,J=8.6Hz,1H),9.31(d,J=9.5Hz,1H).
[0039] [Synthesis of CP-PAH] The synthesis procedure for CP-PAH using compounds 3, 2a, or 7 as raw materials is described below. CP-PAH was also synthesized using compounds 2b or 2c as raw materials using the same procedure. Detailed synthesis procedures for compounds 2b or 2c as raw materials are omitted, and only the chemical reaction formula and yield are shown.
[0040] Synthesis of benzo[p]indeno[1,2,3,4-defg]chrysene (compound 4) [ka]
[0041] Dibenzo[g,p]chrysene (compound 3; 150 mg, 0.45 mmol), PtO (20 mg, 20 mol%), and ion-exchanged water (14 mL) were placed in a 25 mL stainless steel container with a polytetrafluoroethylene (PTFE) inner liner and sealed. The container was placed in an oven and reacted at 260 °C for 72 hours. After cooling to room temperature, the reaction mixture was subjected to Soxhlet extraction overnight using 1,1,2,2-tetrachloroethane as a solvent, and the resulting solution was passed through a silica gel pad. The solvent was removed under reduced pressure from the solution, yielding a yellow solid mixture of compounds 3 and 4. 1 The amount and yield of compound 4 (CP-PAH) were determined using H-NMR, and the amount was 140.9 mg, which was a 72% yield. 1 H NMR(CDCl3,400MHz)δ(ppm) 7.81-7.86(m,6H),8.15(d,J=6.9Hz,2H),8.48(d,J=7.8Hz,2H),8.91(d,J=8.2Hz,2H),9.40(d,J=7.8Hz,2H).
[0042] In addition, the catalyst used to synthesize compound 4 from compound 3 was replaced with another platinum compound (20 mol%), and the reaction was carried out in the same manner to determine the yield. The results are shown in Table 1. As shown in Table 1, it can be seen that all platinum compounds convert compound 3 to compound 4 in good yield. [Table 1]
[0043] Furthermore, as an alternative method for synthesizing compound 4 from compound 3, the results are shown below for when 1 equivalent (100 mol% relative to the substrate) of Fe2O3 is used as a co-catalyst in addition to PtO2, when PdO is used as the catalyst instead of PtO2, and when IrCl3 is used as the catalyst instead of PtO2. As shown below, an improvement in yield was observed when Fe2O3 was used as the co-catalyst, and it can be seen that the desired reaction will also proceed when compounds such as PdO, a palladium compound, or IrCl3, an iridium compound, are used as catalysts.
[0044] [ka]
[0045] Synthesis of benzo[l]indeno[4,3,2,1-cdef]chrysene (compound 6) [ka]
[0046] Compound 2a (150 mg, 0.45 mmol), PtO (20 mg, 20 mol%), and ion-exchanged water (14 mL) were placed in a 25 mL stainless steel vessel equipped with a PTFE liner and sealed. The vessel was placed in an oven and reacted at 260 °C for 72 hours. After cooling to room temperature, the reaction mixture was subjected to Soxhlet extraction overnight using 1,1,2,2-tetrachloroethane as a solvent, and the resulting solution was passed through a silica gel pad. The solvent was removed under reduced pressure from the solution, yielding compound 6 as a yellow solid (9.4 mg, 6% yield). 1H NMR(CDCl3,400MHz) δ(ppm) 7.68-7.72(m,1H),7.75(dd,J=7.9,7.0Hz,1H),7.79-7.84(m,1H),7.97(dd,J=8.2,5.9Hz,2H),8.02(s,2H),8.06-8.08(m,1H) ,8.11(d,J=8.6Hz,1H),8.18(d,J=8.6Hz,1H),8.21(d,J=7.2Hz,1H),8.59(s,1H),9.22(d,J=9.1Hz,1H),9.48(d,J=8.6Hz,1H). HRMS (APCI + ) m / z Calcd.for C 26 H 14 [M + ]:326.1090; Found:326.1100.
[0047] Synthesis of benzo[ghi]fluoranthene (compound 8) 1 [ka]
[0048] Benzo[c]phenanthrene (compound 7; 100 mg, 0.45 mmol), PtO (20 mg, 20 mol%), and ion-exchanged water (14 mL) were placed in a 25 mL stainless steel vessel equipped with a PTFE liner and sealed. The vessel was placed in an oven and reacted at 260 °C for 72 hours. After cooling to room temperature, the reaction mixture was subjected to Soxhlet extraction overnight using chloroform as a solvent, and the resulting solution was passed through a silica gel pad. The solvent was removed under reduced pressure from the solution, yielding compound 8 as a yellow solid (yield: 15.4 mg, 15%). 1 H NMR(CDCl3,400MHz) δ(ppm) 7.69(t,J=7.5Hz,2H),7.93-7.99(m,6H),8.13(d,J=6.8Hz,2H).
[0049] Synthesis of benzo[ghi]fluoranthene (compound 8) 2 and 3 [ka]
[0050] The synthesis was carried out using the same procedure as in Synthesis 1 of benzo[ghi]fluoranthene (compound 8) above, except that 100 mol% of Fe2O3 was used as a co-catalyst in addition to PtO2, and the amount of PtO2, reaction temperature, and reaction time were changed as shown in the chemical reaction formula above. As a result, in a system using PtO2 (40 mol%) and Fe2O3 (100 mol%), compound 8 was obtained in a 12% yield when reacted at 200°C for 168 hours, and in a 6% yield when reacted at 180°C for 72 hours.
[0051] Below, CP-PAH was synthesized using the same procedure as above for compounds 2b or 2c. Only the chemical reaction formula and yield are shown for these compounds. 1 Identification was carried out by H-NMR.
[0052] [ka]
[0053] As shown above, it is clear that according to the present invention, CP-PAH can be synthesized by a simple method known as hydrothermal synthesis.
Claims
1. A method for producing a cyclopenta-fused polycyclic aromatic hydrocarbon compound, comprising allowing a reaction substrate having a structure represented by the following formula (1) at least as a partial structure to undergo a reaction with a catalyst comprising at least one compound selected from the group consisting of platinum compounds, palladium compounds, and iridium compounds under hydrothermal synthesis conditions to obtain a compound having a structure represented by the following formula (2) at least as a partial structure: 【Chemical 1】
2. The platinum compound is PtO ２ , Pt, PtCl ２ , K. ２ [PtCl ４ ], H ２ [PtCl ６ ]・6H ２ O and Na ２ [PtCl ６ ]・6H ２ O, the palladium compound is PdO, and the iridium compound is IrCl ３ The method according to claim 1, wherein
3. The method according to claim 1, wherein the temperature of the hydrothermal synthesis conditions is 150°C or higher.
4. 2. The method according to claim 1, wherein the amount of the platinum compound to be reacted is 10 mol % to 70 mol % based on the reaction substrate.
5. Furthermore, Fe ２ O ３ 2. The method according to claim 1, wherein the catalyst is subjected to hydrothermal conditions in the presence of a promoter.