Method for producing phenanthroline derivatives

Abstract

To provide a method of producing a phenanthroline derivative little in impurities, high in productivity.SOLUTION: A method of producing a phenanthroline derivative expressed by the following (1) includes: a step of reacting a dihalogenated aromatic compound with an organic lithium reagent; a step of reacting a lithiation reaction product with 2-phenyl-1,10-phenanthroline, preferably with 1,10-phenanthroline; further a step of reacting the reaction product with an organic lithium reagent; a step of reacting the lithiation reaction product with 1,10-phenanthroline; and further a step of subjecting the reaction product to iodine oxidation to obtain a crude product of a phenanthroline derivative.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing a phenanthroline derivative. [Background technology]

[0002] Phenanthroline derivatives are useful compounds as light-emitting device materials for, for example, display elements, flat panel displays, backlights, lighting, interiors, signs, billboards, electrophotographic machines, optical signal generators, etc. As methods for producing phenanthroline derivatives having a structure represented by the general formula (1) described below, for example, a method has been proposed in which dibromobenzene is dilithiated with n-butyllithium or sec-butyllithium, followed by reaction with 2-phenyl-1,10-phenanthroline and subsequent oxidation (see, for example, Patent Document 1), and a method has been proposed in which 1,3-di(1,10-phenanthroline-2-yl)benzene is reacted with phenyllithium and subsequent oxidation (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-189660 [Patent Document 2] International Publication No. 2006 / 021982 Summary of the Invention [Problem to be solved by the invention]

[0004] The production methods disclosed in Patent Documents 1 and 2 are so-called batch processes in which raw materials are placed in a reaction vessel, reacted, and the product is isolated each time. In batch processes, the reaction rate tends to decrease as the production of the target product progresses, and side reactions tend to occur.

[0005] Therefore, a method for producing phenanthroline derivatives using a so-called flow process, in which raw materials are continuously supplied to a thin tubular reaction vessel (reactor) and a product is continuously obtained, has been considered. Patent Documents 1 and 2 disclose methods for oxidation using oxidizing agents such as manganese dioxide and nitrobenzene. However, when these oxidizing agents are applied to a flow process, the reaction must be stopped using a protic solvent such as water or alcohol before oxidation. Furthermore, manganese dioxide is a heterogeneous oxidizing agent that is insoluble in solvents and requires large amounts to be added, which makes it prone to generating by-products derived from the oxidizing agent. Furthermore, when applied to a flow process, the flow path is prone to clogging, posing a productivity issue. On the other hand, nitrobenzene has environmental and safety issues and is not suitable for mass production.

[0006] In view of the above problems of the prior art, an object of the present invention is to provide a method for producing phenanthroline derivatives with few impurities and high productivity. [Means for solving the problem]

[0007] The method for producing a phenanthroline derivative of the present invention is characterized in that iodine is used as an oxidizing agent and at least the steps up to the oxidation step are carried out continuously.

[0008] A first aspect of the present invention is a method for producing a phenanthroline derivative having a structure represented by the following general formula (1): (Step 1A) reacting a dihalogenated aromatic compound with an organolithium reagent; (Step 2A) reacting the lithiation reaction product of Step 1A with a compound having a structure represented by the following general formula (2): (Step 3A) reacting the reaction product of Step 2A with an organolithium reagent; (Step 4A) reacting the lithiation reaction product of Step 3A with a compound having a structure represented by the following general formula (2): (Step 5A) a step of oxidizing the reaction product of Step 4A with iodine to obtain a crude product of a phenanthroline derivative; (Step 6A) a step of recrystallizing the crude product of the phenanthroline derivative obtained in Step 5A and further sublimating it; The method for producing a phenanthroline derivative comprises the steps in this order, and at least steps 1A to 5A are carried out continuously.

[0009] [ka]

[0010] In the general formula (1), R2 to R13 may be the same or different and represent a hydrogen atom, a substituted or unsubstituted aryl group, a heteroaryl group, an alkyl group, a cycloalkyl group, an alkoxy group, an aryloxy group, an alkenyl group, a cycloalkenyl group, an alkynyl group, an alkylthio group, an arylthio group, or a cyano group. R1 and R14 may be the same or different and represent a substituted or unsubstituted aryl group, a heteroaryl group, an alkyl group, or a cycloalkyl group.

[0011] [ka]

[0012] In the above general formula (2), R15 to R21 may be the same or different and represent a hydrogen atom, a substituted or unsubstituted aryl group, a heteroaryl group, an alkyl group, a cycloalkyl group, an alkoxy group, an aryloxy group, an alkenyl group, a cycloalkenyl group, an alkynyl group, an alkylthio group, an arylthio group, or a cyano group.

[0013] A second aspect of the present invention is a method for producing a phenanthroline derivative having a structure represented by the following general formula (3): (Step 1B) reacting a substituted or unsubstituted halogenated aromatic compound with an organolithium reagent; (Step 2B) reacting the lithiation reaction product of Step 1B with a compound having a structure represented by the following general formula (4): (Step 3B) a step of oxidizing the reaction product of Step 2B with iodine to obtain a crude product of a phenanthroline derivative; (Step 4B) a step of recrystallizing the crude product of the phenanthroline derivative obtained in Step 3B and further sublimating it; The method for producing a phenanthroline derivative comprises the steps in this order, and at least steps 1B to 3B are carried out continuously.

[0014] [ka]

[0015] In the general formula (3), R23 to R28 may be the same or different and represent a hydrogen atom, a substituted or unsubstituted aryl group, a heteroaryl group, an alkyl group, a cycloalkyl group, an alkoxy group, an aryloxy group, an alkenyl group, a cycloalkenyl group, an alkynyl group, an alkylthio group, an arylthio group, or a cyano group. R22 represents a substituted or unsubstituted aryl group, a heteroaryl group, an alkyl group, or a cycloalkyl group.

[0016] [ka]

[0017] In the above general formula (4), R29 to R34 may be the same or different and represent a hydrogen atom, a substituted or unsubstituted aryl group, a heteroaryl group, an alkyl group, a cycloalkyl group, an alkoxy group, an aryloxy group, an alkenyl group, a cycloalkenyl group, an alkynyl group, an alkylthio group, an arylthio group, or a cyano group. [Effects of the Invention]

[0018] According to the method for producing a phenanthroline derivative of the present invention, a phenanthroline derivative containing few impurities can be produced with high productivity. DETAILED DESCRIPTION OF THE INVENTION

[0019] The present invention will be described in detail below.

[0020] A first aspect of the present invention is a method for producing a phenanthroline derivative having a structure represented by the following general formula (1): (Step 1A) reacting a dihalogenated aromatic compound with an organolithium reagent; (Step 2A) reacting the lithiation reaction product of Step 1A with a compound having a structure represented by the following general formula (2): (Step 3A) reacting the reaction product of Step 2A with an organolithium reagent; (Step 4A) reacting the lithiation reaction product of Step 3A with a compound having a structure represented by the following general formula (2): (Step 5A) a step of oxidizing the reaction product of Step 4A with iodine to obtain a crude product of a phenanthroline derivative; (Step 6A) a step of recrystallizing the crude product of the phenanthroline derivative obtained in Step 5A and further sublimating it; The method for producing a phenanthroline derivative comprises the steps in this order, and at least steps 1A to 5A are carried out continuously.

[0021] [ka]

[0022] In the general formula (1), R2 to R13 may be the same or different and represent a hydrogen atom, a substituted or unsubstituted aryl group, a heteroaryl group, an alkyl group, a cycloalkyl group, an alkoxy group, an aryloxy group, an alkenyl group, a cycloalkenyl group, an alkynyl group, an alkylthio group, an arylthio group, or a cyano group. Among these, a hydrogen atom is preferred, as it has little steric hindrance, allowing the reaction at the R1 and / or R14 position to proceed efficiently and further suppressing impurities resulting from side reactions.

[0023] R1 and R14 may be the same or different and represent a substituted or unsubstituted aryl group, heteroaryl group, alkyl group, or cycloalkyl group. Among these, aryl groups and heteroaryl groups are preferred, as they have a high glass transition temperature and can improve heat resistance. Furthermore, since they have high electron mobility, they can reduce the driving voltage when used as a light-emitting device material. Aryl groups are more preferred, and phenyl groups are even more preferred.

[0024] [ka]

[0025] In the general formula (2), R15 to R21 may be the same or different and represent a hydrogen atom, a substituted or unsubstituted aryl group, a heteroaryl group, an alkyl group, a cycloalkyl group, an alkoxy group, an aryloxy group, an alkenyl group, a cycloalkenyl group, an alkynyl group, an alkylthio group, an arylthio group, or a cyano group. However, the compound having the structure represented by the general formula (2) is a raw material for a phenanthroline derivative having the structure represented by the general formula (1), and the positions of R15 to R21 in the general formula (2) correspond to the positions of R1 to R7 and R14 to R8 in the general formula (1), respectively.

[0026] When any of R2 to R7 and R13 to R8 in general formula (1) is a hydrogen atom, it is preferable that the corresponding R16 to R21 in general formula (2) is also a hydrogen atom. On the other hand, when any of R1 to R7 and R14 to R8 in general formula (1) is other than a hydrogen atom, the corresponding R15 to R21 in general formula (2) may be a hydrogen atom or may be other than a hydrogen atom. When the corresponding R15 to R21 in general formula (2) are hydrogen atoms, a desired phenanthroline derivative can be obtained by providing a step of substituting the hydrogen atom with a group in general formula (1).

[0027] More specifically, when R1 and / or R14 in general formula (1) are phenyl groups and a compound in which R15 in general formula (2) is a hydrogen atom is used in the (Step 2A) and / or (Step 4A), a step of substituting the hydrogen atom of R15 with a phenyl group is provided. That is, the (Step 5A) is at least (Step 5A-1) a step of oxidizing the reaction product of Step 4A with iodine; (Step 5A-2) a step of reacting the reaction product of Step 5A-1 with phenyllithium; (Step 5A-3) A step of oxidizing the reaction product of Step 5A-2 with iodine to obtain a crude product of a phenanthroline derivative. It is preferable to have these in this order.

[0028] In the first embodiment of the present invention, a crude phenanthroline derivative is obtained by the reactions from (Step 1A) to (Step 5A). In batch-type production methods, the reaction rate tends to decrease as the production of the target product progresses, and impurities due to side reactions such as self-condensation of dihalogenated benzenes tend to be easily produced. However, by continuously performing the above-mentioned steps and shortening the reaction time of the lithiation reaction, the production of such impurities can be suppressed. Furthermore, unlike oxidizing agents such as manganese dioxide and nitrobenzene, which require the reaction to be stopped before oxidation, by selecting iodine as the oxidizing agent, it is not necessary to perform (Step 5A) separately, and (Step 1A) to (Step 5A) can be performed continuously. Furthermore, compared to conventionally known oxidizing agents, impurities due to side reactions with the oxidizer can be suppressed.

[0029] (Step 6A) may be carried out continuously or batchwise.

[0030] In the above general formulas (1) and (2), the aryl group is an aromatic hydrocarbon group obtained by removing one hydrogen atom from an aromatic ring of an aromatic hydrocarbon compound, and may be either a single ring or a condensed ring. Examples of the aryl group include a phenyl group, a naphthyl group, a fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthryl group, an anthracenyl group, a benzophenanthryl group, a benzanthracenyl group, a chrysenyl group, a pyrenyl group, a fluoranthenyl group, a triphenylenyl group, a benzofluoranthenyl group, a dibenzoanthracenyl group, a perylenyl group, and a helicenyl group. Among these, a phenyl group, a naphthyl group, a fluorenyl group, a phenanthryl group, an anthracenyl group, a pyrenyl group, a fluoranthenyl group, and a triphenylenyl group are preferred. These substituents may be further substituted. In the present invention, groups in which multiple phenyl groups are bonded via single bonds, such as biphenyl groups and terphenyl groups, are considered to be phenyl groups having an aryl group as a substituent. The number of ring carbon atoms in the aryl group is not particularly limited, but is preferably in the range of 6 to 40, more preferably 6 to 30. Furthermore, in a phenyl group, when two adjacent carbon atoms in the phenyl group each have a substituent, these substituents may form a ring structure. Depending on the structure, the resulting group may fall into one or more of the following categories: a "substituted phenyl group," an "aryl group having a structure in which two or more rings are fused," or a "heteroaryl group having a structure in which two or more rings are fused."

[0031] A heteroaryl group is a cyclic aromatic group containing one or more atoms other than carbon and hydrogen, i.e., heteroatoms, in the ring, and may be either a single ring or a condensed ring. The heteroatom is preferably a nitrogen atom, an oxygen atom, or a sulfur atom. Examples of heteroaryl groups include pyridyl, furanyl, thienyl, quinolinyl, isoquinolinyl, pyrazinyl, pyrimidyl, pyridazinyl, triazinyl, naphthyridinyl, cinnolinyl, phthalazinyl, quinoxalinyl, quinazolinyl, benzofuranyl, benzothienyl, indolyl, dibenzofuranyl, dibenzothienyl, carbazolyl, benzocarbazolyl, carbolinyl, indolocarbazolyl, benzofurocarbazolyl, benzothienocarbazolyl, dihydroindenocarbazolyl, benzoquinolinyl, acridinyl, dibenzoacridinyl, benzimidazolyl, imidazopyridyl, benzoxazolyl, benzothiazolyl, and phenanthrolinyl. The heteroaryl group may be substituted or unsubstituted. When substituted, examples of the substituent include the aforementioned aryl group, heteroaryl group, the later-described alkyl group, etc. The number of ring carbon atoms of the heteroaryl group is not particularly limited, but is preferably in the range of 2 to 40, more preferably 2 to 30.

[0032] The alkyl group refers to a saturated aliphatic hydrocarbon group such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, or a pentyl group, which may be substituted or unsubstituted. When substituted, examples of the substituent include the aforementioned aryl group, heteroaryl group, and the alkoxy group described below. The number of carbon atoms in the alkyl group is not particularly limited, but is preferably in the range of 1 to 20, more preferably 1 to 8.

[0033] The cycloalkyl group refers to a saturated alicyclic hydrocarbon group such as a cyclopropyl group, a cyclohexyl group, a norbornyl group, or an adamantyl group, which may be substituted or unsubstituted. When substituted, examples of the substituent include the aforementioned aryl group, heteroaryl group, and the alkoxy group described below. The number of ring carbon atoms of the cycloalkyl group is not particularly limited, but is preferably in the range of 3 to 20.

[0034] The alkoxy group refers to a functional group in which an aliphatic hydrocarbon group is bonded via an ether bond, such as a methoxy group, an ethoxy group, or a propoxy group, and the aliphatic hydrocarbon group may be substituted or unsubstituted. When the aliphatic hydrocarbon group is substituted, examples of the substituent include the aforementioned aryl group, heteroaryl group, and alkoxy group. The number of carbon atoms in the alkoxy group is not particularly limited, but is preferably in the range of 1 to 20.

[0035] The aryloxy group refers to a functional group, such as a phenoxy group, to which an aromatic hydrocarbon group is bonded via an ether bond, and the aromatic hydrocarbon group may be substituted or unsubstituted. If the aromatic hydrocarbon group is substituted, examples of the substituent include the groups exemplified as the substituent for the aryl group. The number of ring carbon atoms of the aryloxy group is not particularly limited, but is preferably in the range of 6 to 40.

[0036] The alkenyl group refers to an unsaturated aliphatic hydrocarbon group containing a double bond, such as a vinyl group or a butadienyl group, which may be substituted or unsubstituted. In the case of a substitution, examples of the substituent include the aforementioned aryl group, heteroaryl group, and alkoxy group. The number of carbon atoms in the alkenyl group is not particularly limited, but is preferably in the range of 2 to 20.

[0037] The cycloalkenyl group refers to an unsaturated alicyclic hydrocarbon group containing a double bond, such as a cyclopentenyl group, a cyclopentadienyl group, or a cyclohexenyl group, which may be substituted or unsubstituted. When substituted, examples of the substituent include the aforementioned aryl group, heteroaryl group, and alkoxy group. The number of ring carbon atoms of the cycloalkenyl group is not particularly limited, but is preferably in the range of 3 to 20.

[0038] The alkynyl group refers to an unsaturated aliphatic hydrocarbon group containing a triple bond, such as an ethynyl group, which may be substituted or unsubstituted. When substituted, examples of the substituent include the aforementioned aryl group, heteroaryl group, and alkoxy group. The number of carbon atoms in the alkynyl group is not particularly limited, but is preferably in the range of 2 to 20.

[0039] An alkylthio group is an alkoxy group in which the oxygen atom of the ether bond is replaced with a sulfur atom. The aliphatic hydrocarbon group of the alkylthio group may be substituted or unsubstituted. When substituted, examples of the substituent include the groups exemplified as the substituent of the alkyl group. The number of carbon atoms in the alkylthio group is not particularly limited, but is preferably in the range of 1 to 20.

[0040] An arylthio group is an aryloxy group in which the oxygen atom of the ether bond is substituted with a sulfur atom. The aromatic hydrocarbon group in the arylthio group may be substituted or unsubstituted. The number of ring carbon atoms in the arylthio group is not particularly limited, but is preferably in the range of 6 to 40.

[0041] A cyano group is a functional group with the structure -C≡N, where it is the carbon atom that is bonded to other functional groups.

[0042] An example of a method for producing the phenanthroline derivative according to the first aspect of the present invention is shown below, where X represents a halogen.

[0043] [ka]

[0044] Another example of the method for producing a phenanthroline derivative according to the first embodiment is a case where a compound of general formula (2) in which R15 is a hydrogen atom is used in the above-mentioned (Step 2A) and (Step 4A), where X is a halogen atom.

[0045] [ka]

[0046] In (Step 1A), the dihalogenated aromatic compound is preferably a dihalogenated benzene from the viewpoints of reducing steric hindrance, increasing reactivity, and further suppressing side reactions to further reduce impurities. Examples of dihalogenated benzene include 1,3-dibromobenzene, 1,3-diiodobenzene, and 1-bromo-3-iodobenzene. Two or more of these may be used. Among these, 1,3-dibromobenzene is preferred.

[0047] Examples of organolithium reagents include n-butyllithium, sec-butyllithium, and tert-butyllithium. Two or more of these may be used. Among these, n-butyllithium is preferred.

[0048] These are preferably reacted in a solution state, and examples of the solvent include saturated hydrocarbon solvents having 5 to 8 carbon atoms, such as pentane, hexane, heptane, octane, and cyclohexane, and ether solvents, such as tert-butyl methyl ether, cyclopentyl methyl ether, dimethyl ether, diethyl ether, dibutyl ether, 1,4-dioxane, and tetrahydrofuran. Two or more of these may be used. The solution concentration of each raw material is preferably 5.0 M or less, and more preferably 2.0 M or less.

[0049] It is preferable to use 0.8 to 1.1 equivalents of the organolithium reagent relative to the dihalogenated aromatic compound.

[0050] The flow rate (ml / min) of each raw material is preferably 1 ml / min or more, more preferably 4 ml / min or more, and the reaction temperature is preferably -20 to 40°C.

[0051] The residence time (reaction time) in (Step 1A) is preferably 0.1 to 3 seconds, taking into consideration the time required for the halogen-lithium exchange reaction and the stabilization time of the lithiation reaction product. Furthermore, from the viewpoint of further suppressing side reactions and further reducing impurities, 2.5 seconds or less is more preferable. On the other hand, from the viewpoint of completing the dilithiation reaction, 0.5 seconds or more is more preferable.

[0052] In (Step 2A), R16 to R21 in the general formula (2) are preferably hydrogen atoms from the viewpoint of reducing steric hindrance, increasing reactivity, and further suppressing side reactions. On the other hand, R15 is preferably a hydrogen atom or an aryl, and the aryl group is more preferably a phenyl group. That is, as the compound having the structure represented by the general formula (2), 1,10-phenanthroline or 2-phenyl-1,10-phenanthroline is preferred.

[0053] In (Step 2A), the compound having the structure represented by the general formula (2) is preferably used in an amount of 0.8 to 1.1 equivalents relative to the dihalogenated aromatic compound. The residence time in (Step 2A) is preferably 4 to 6 seconds, taking into account the time required for the reaction of phenanthroline. The reaction temperature is preferably -20 to 40°C.

[0054] A preferred embodiment of (Step 3A) is the same as (Step 1A), and a preferred embodiment of (Step 4A) is the same as (Step 2A).

[0055] In (Step 5A), iodine is preferably used in an amount of 1.0 to 1.2 equivalents relative to the amount of the dihalogenated aromatic compound used. Furthermore, the residence time in (Step 5A) is preferably 2 to 4 seconds, taking into account the time required for the oxidation reaction. The reaction temperature is preferably −20 to 40° C. In the present invention, as described above, iodine is used as the oxidizing agent. When conventional production methods using oxidizing agents such as manganese dioxide or nitrobenzene are applied to a flow process, it is necessary to quench the reaction using a protic solvent such as water or alcohol before oxidation. In contrast, in the present invention, the oxidation reaction can proceed directly in an aprotic solvent without quenching the reaction using a protic solvent. Furthermore, unlike manganese dioxide and nitrobenzene, which are prone to clogging flow paths when applied to a flow process, iodine is an oxidizing agent suitable for a flow process, is less likely to cause side reactions between the intermediate product and the oxidizing agent, and can suppress impurities.

[0056] It is preferable that iodine is dissolved in a solvent and supplied into the flow channel.

[0057] Examples of solvents that dissolve iodine include aliphatic alcohol solvents such as methanol and ethanol, aromatic hydrocarbon solvents such as benzene, toluene, xylene, and nitrobenzene, halogenated hydrocarbon solvents such as dichloromethane and chloroform, ether solvents such as diethyl ether, tert-butyl methyl ether, cyclopentyl methyl ether, tetrahydrofuran, 1,4-dioxane, and dimethoxyethane, N,N'-dimethylformamide, and N,N'-dimethylimidazolidinone (DMI), etc. Two or more of these may be used.

[0058] The concentration of the iodine solution can be appropriately selected depending on the solvent used, and for example, in the case of an ethanol solution or a tetrahydrofuran solution, the concentration is preferably 1 to 10% by weight.

[0059] The reaction time for (Step 5A), (Step 5A-1) and (Step 5A-3) is preferably about 2 to 4 seconds.

[0060] In (Step 5A-2), the reaction product obtained in (Step 5A-1) is reacted with phenyllithium. Phenyllithium can be obtained, for example, from Merck Ltd. When a compound in which R15 in general formula (2) is a hydrogen atom is used in (Step 2A) and (Step 4A), it is preferable to use 2 to 4 equivalents of phenyllithium relative to the reaction product obtained in (Step 5A-1) in order to replace each of the R15 reacted in each step with a phenyl group. Examples of solvents that can be used in this reaction include the aforementioned aliphatic alcohol solvents, aromatic hydrocarbon solvents, and ether solvents.

[0061] The reaction temperature in (Step 5A-2) can be appropriately selected depending on the solvent used, and is preferably -20 to 0°C.

[0062] The reaction time in (Step 5A-2) is preferably about 2 to 4 seconds.

[0063] In (Step 6A), the crude product of the phenanthroline derivative is recrystallized and further purified by sublimation. By this purification, by-products and the like can be separated and removed, thereby reducing impurities.

[0064] Examples of solvents used for recrystallization include toluene, hexane, tetrahydrofuran, dioxane, dimethoxyethane, ethanol, methanol, acetone, methyl ethyl ketone, ethyl acetate, n-butyl lactone, nitrobenzene, dichloromethane, chloroform, dimethyl sulfoxide, dimethylformamide, 1-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, pyridine, triethylamine, etc. Two or more of these may be used.

[0065] The heating temperature and crystallization temperature for recrystallization can be appropriately selected depending on the solvent used, and is preferably 0 to 130°C.

[0066] The sublimation temperature is preferably 400°C or less, and the degree of vacuum during sublimation purification is 1.0 x 10 -3 Pa or less is preferred.

[0067] An example of a method for adjusting the iodine content within the preferred range described below is a method of washing the crude product of the phenanthroline derivative after oxidation. For washing, it is preferable to use an aqueous sodium thiosulfate solution. More specifically, the crude product of the phenanthroline derivative after oxidation is washed with an aqueous sodium thiosulfate solution and then washed with water, thereby removing the contained iodine with the sodium thiosulfate reducing agent. Furthermore, if iodide salt (lithium iodide) is produced in the reaction system, it is also removed by washing with water. Since the amount of iodine removed varies depending on the concentration of the aqueous sodium thiosulfate solution, the number of washes, and the number of water washes, it is preferable to select these conditions according to the desired iodine content.

[0068] Next, toluene is added, heated, and washed to form a slurry, and then ethanol, which has high solubility for iodine and iodide salt (lithium iodide), is added, heated, and washed to form a slurry, followed by recrystallization and sublimation for purification. For recrystallization, an anisole / toluene solution is preferably used, and after sublimation, a tetrahydrofuran / methanol solution is preferably used.

[0069] For example, if the iodine content of the crude product of a phenanthroline derivative after oxidation is several tens of thousands of ppm, the solution can be washed twice with a 0.5 M aqueous solution of sodium thiosulfate, then washed with water. After adding 50 ml of ethanol to 1 g of the sample, the mixture is heated at 80°C for one hour to form a slurry, and then recrystallized and sublimated using the method described above. The iodine content will be reduced to approximately 1 ppm to 60 ppm. If the same water washing, recrystallization, and sublimation procedures are carried out without washing with the aqueous solution of sodium thiosulfate, the iodine content will be approximately 60 ppm to 600 ppm. If the same recrystallization and sublimation procedures are carried out, the iodine content will be approximately 600 ppm to 1,000 ppm.

[0070] In the method for producing a phenanthroline derivative of the present invention, in order to continuously carry out the above steps, it is preferable to apply a so-called flow process in which raw materials are continuously supplied to a thin tubular reaction vessel (reactor) and a product is continuously obtained. That is, in this process, the raw materials are pumped from a reservoir into a flow path, mixed in a mixer section, and the reaction proceeds in the reaction vessel (reactor) while flowing through the flow path, and the produced compound is discharged from the flow path.

[0071] The diffusion rate and reaction rate of raw materials depend on the size of the reaction vessel, and because the space for mixing raw materials is smaller than in a batch process, the raw materials are mixed accurately and quickly at a mixing ratio determined by the flow rate. This prevents a decrease in reaction rate and further suppresses side reactions. In addition, a flow process makes it easier to maintain a uniform temperature throughout the reaction system, and can also suppress the generation of impurities due to side reactions caused by localized temperature increases.

[0072] Examples of the pump include a plunger pump and a diaphragm pump. Examples of the shape of the mixer include a T-shape and a Y-shape. The flow path diameter (inner diameter) of the mixer is preferably 100 μm to 3 mm.

[0073] The method for producing a phenanthroline derivative of the present invention provides a phenanthroline derivative represented by the general formula (1) containing a certain amount of iodine. Note that "containing iodine" does not mean that the phenanthroline derivative is contained as a part of its structure, but rather that the iodine is contained as a useful additive. For example, when used as a light-emitting element material for an organic electroluminescence (EL) display device, the inclusion of a certain amount of iodine can reduce the driving voltage of the light-emitting element and improve its durability through element-trapping effects and improved conductivity. The iodine content is preferably 60 ppm or more. On the other hand, keeping the iodine content below a certain level can suppress electrode corrosion, such as alkaline migration, and improve the luminous efficiency and durability of the light-emitting element. The iodine content is preferably 10,000 ppm or less.

[0074] Here, the iodine content of the phenanthroline derivative can be measured by X-ray fluorescence analysis. Specifically, the phenanthroline derivative is compression-molded using a press, and the surface is covered with a polypropylene film to suppress volatilization from the surface, to prepare a measurement sample. The obtained measurement sample is irradiated with primary X-rays using an X-ray fluorescence analyzer, and the intensity of the fluorescent X-rays of iodine that appears when returning from an excited state to the ground state is measured. The iodine content is calculated from a calibration curve previously prepared using samples with known iodine contents.

[0075] The compound having the structure represented by the general formula (2) used in the above (Step 2A) and (Step 4A) can also be produced using the flow process of the present invention. A second aspect of the present invention is a method for producing a phenanthroline derivative having a structure represented by the following general formula (3): (Step 1B) reacting a substituted or unsubstituted halogenated aromatic compound with an organolithium reagent; (Step 2B) reacting the lithiation reaction product of Step 1B with a compound having a structure represented by the following general formula (4): (Step 3B) a step of oxidizing the reaction product of Step 2B with iodine to obtain a crude product of a phenanthroline derivative; (Step 4B) a step of recrystallizing the crude product of the phenanthroline derivative obtained in Step 3B and further sublimating it; This method for producing a phenanthroline derivative comprises the steps in this order, and at least steps 1B to 3B are continuously carried out. As in the first embodiment, by using iodine as an oxidizing agent, the oxidation reaction can proceed directly in an aprotic solvent without terminating the reaction using a protic solvent. Furthermore, unlike manganese dioxide and nitrobenzene, which tend to clog flow paths when applied to a flow process, iodine is an oxidizing agent suitable for a flow process, is less likely to cause side reactions between the intermediate product and the oxidizing agent, and can suppress impurities.

[0076] [ka]

[0077] In the general formula (3), R23 to R28 may be the same or different and represent a hydrogen atom, a substituted or unsubstituted aryl group, a heteroaryl group, an alkyl group, a cycloalkyl group, an alkoxy group, an aryloxy group, an alkenyl group, a cycloalkenyl group, an alkynyl group, an alkylthio group, an arylthio group, or a cyano group. R22 represents a substituted or unsubstituted aryl group, a heteroaryl group, an alkyl group, or a cycloalkyl group.

[0078] [ka]

[0079] In the above general formula (4), R29 to R34 may be the same or different and represent a hydrogen atom, a substituted or unsubstituted aryl group, a heteroaryl group, an alkyl group, a cycloalkyl group, an alkoxy group, an aryloxy group, an alkenyl group, a cycloalkenyl group, an alkynyl group, an alkylthio group, an arylthio group, or a cyano group.

[0080] In the above general formula (3), R15 in general formula (2) is limited to a substituted or unsubstituted aryl group, heteroaryl group, alkyl group, or cycloalkyl group, and R23 to R28 correspond to R16 to R21 in general formula (2), respectively. Therefore, in general formula (3), R23 to R28 are preferably hydrogen atoms, and R22 is preferably an aryl group, more preferably a phenyl group. That is, 2-phenyl-1,10-phenanthroline is preferred as the phenanthroline derivative having the structure represented by the general formula (3).

[0081] The compound having the structure represented by the general formula (4) is a raw material for a phenanthroline derivative having the structure represented by the general formula (3), and the positions of R29 to R34 in the general formula (4) correspond to the positions of R23 to R28 in the general formula (3), respectively. Therefore, R29 to R34 in the general formula (4) are preferably hydrogen atoms.

[0082] An example of a method for producing the phenanthroline derivative according to the second aspect of the present invention is shown below, where X represents a halogen.

[0083] [ka]

[0084] (Step 1B) corresponds to (Step 1A) in the first embodiment. The halogenated aromatic compound is preferably a halogenated benzene from the viewpoint of reducing steric hindrance, increasing reactivity, and further suppressing side reactions. Other preferred embodiments are the same as (Step 1A).

[0085] (Step 2B) corresponds to (Step 2A) in the first embodiment. R29 to R34 in the general formula (4) are preferably hydrogen atoms from the viewpoint of reducing steric hindrance, increasing reactivity, and further suppressing side reactions. That is, 1,10-phenanthroline is preferred as the compound having the structure represented by the general formula (4). Other preferred embodiments are the same as those in (Step 2A).

[0086] (Step 3B) corresponds to (Step 5A). A preferred embodiment is the same as (Step 5A). [Example]

[0087] The evaluations in each of the examples and comparative examples were carried out by the following methods.

[0088] (1) Iodine content The phenanthroline derivatives obtained in each example and comparative example were compression-molded using a press, and the surface was covered with a polypropylene film to suppress surface volatilization. The resulting samples were irradiated with primary X-rays using an X-ray fluorescence analyzer (Rigaku Corporation, wavelength-dispersive X-ray fluorescence analyzer ZSX PRIMUS IV) to measure the intensity of iodine fluorescence during the return from the excited state to the ground state. An energy window (27.44 keV to 28.56 keV) was set around the iodine Kα X-ray fluorescence peak at 28.3 keV. A trapezoid was set within the window to represent the background component. The number of counts corresponding to this area was taken as the multiple scattering component and subtracted from the total counts within the window to determine the net X-ray fluorescence intensity of iodine. The iodine content was calculated from a calibration curve prepared in advance using samples with known iodine contents.

[0089] (2) Purity of phenanthroline derivatives 4.0 mg of the phenanthroline derivative obtained in each example and comparative example was weighed into a glass container, and 40 ml of THF was added to dissolve it. 1 ml of the prepared solution was transferred to an HPLC vial to prepare an HPLC measurement sample. Then, analysis was performed by HPLC under the following conditions. The purity was calculated from the absorption intensity area ratio of the large peak of the phenanthroline derivative having the structure represented by the structural formula (1) detected at a retention time of 12 to 13 minutes. It can be said that the higher the purity, the more impurities are suppressed. Equipment: Shimadzu Corporation Nexeralite system (LC-40 series) Detector: Shimadzu Corporation photodiode array detector (SPD-M40) Column type: High-purity spherical silica gel particles with octyl-group chemically bonded packing material, reversed-phase column Theoretical plate number: 105,000±10,000(N / m) Column temperature: 45℃ Flow rate: 1.0mL / min Injection volume: 10μL Measurement sample concentration: 4.0 mg / 40 ml THF Mobile phase: Solution A: 0.1% by weight phosphoric acid aqueous solution, Solution B: acetonitrile / tetrahydrofuran mixture (weight ratio 80 / 20) Flow conditions: Initially, the volume ratio of solution A to solution B was 55 / 45, and after a retention time of 25 minutes, only solution B was used, with a linear gradient for the first 25 minutes. Analysis software: Shimadzu Corporation LabSolutions Measurement wavelength: 254nm Phenanthroline derivative detection area: 6,000,000 or more Minimum area for impurity detection: 60 Width(W):1sec Slope(S):1,000μV / min Drift(D):300μV / min T.DBL(T): 1,000 min.

[0090] (3) Driving voltage, external quantum efficiency (EQE), and durability of light-emitting devices A glass substrate (manufactured by Geomatec Co., Ltd., 10 Ω / □, sputtered product) on which a 100 nm ITO transparent conductive film had been deposited as an anode was cut into 75 mm × 75 mm pieces and etched. The resulting substrate was ultrasonically cleaned for 15 minutes using "Semicoclean" (registered trademark) 56 (trade name, manufactured by Furuuchi Chemical Co., Ltd.) and then washed with ultrapure water. This substrate was subjected to UV-ozone treatment for 1 hour immediately before fabricating the device, and then placed in a vacuum deposition apparatus, where the degree of vacuum in the apparatus was 5 × 10. -4The chamber was evacuated to a pressure of 10 Pa or less. Using a resistance heating method, first, a 10-nm HIL represented by the following structural formula was deposited as a hole injection layer. Then, a 105-nm HTL-A represented by the following structural formula and a 10-nm HTL-B represented by the following structural formula were deposited as a hole transport layer. Next, a 20-nm thick mixed layer of a host material Host-A represented by the following structural formula and a dopant material Dopant-B represented by the following structural formula was deposited as an emissive layer with a doping concentration of 3 wt%. Next, a 20-nm thick ETL-A represented by the following structural formula was deposited as an electron transport layer. Next, a 12-nm thick mixed layer of the phenanthroline derivative and lithium obtained in Examples 1 to 3 and Comparative Examples 1 and 2 was deposited as an N-type charge generation layer with a doping concentration of 1 wt%. Next, a 10-nm HIL was deposited, followed by a 55-nm HTL-A and a 10-nm HTL-B. Next, as the light-emitting layer, a mixed layer of a host material Host-A and a dopant material Dopant-B was vapor-deposited to a thickness of 20 nm so that the doping concentration was 3 wt%. Next, as the electron-transporting layer, ETL-A was vapor-deposited to a thickness of 20 nm. Next, as the electron-injecting layer, a mixed layer of the phenanthroline derivative and lithium obtained in Examples 1 and 2 and Comparative Examples 1 and 2 was vapor-deposited to a thickness of 10 nm so that the doping concentration was 1 wt%. Next, aluminum was vapor-deposited to a thickness of 100 nm so that the cathode was formed, and a light-emitting device measuring 25 mm × 25 mm was fabricated.

[0091] [ka]

[0092] [ka]

[0093] The obtained light-emitting device was subjected to a current of 10 mA / cm 2 The device was driven with a DC current of 10 mA / cm at a temperature of 20 to 30°C, and the initial driving voltage, initial luminance, and EQE (external quantum efficiency), which is an index of luminous efficiency, were measured. 2The luminance was measured when the device was driven with a direct current at 1000 kJ / s, and the time it took for the luminance to decrease by 5% from the initial luminance was evaluated as durability.

[0094] Example 1 (Step 1A) to (Step 5A) were carried out by a flow reaction under the following conditions. Syringe pump: YMC Corporation Model YSP-301 high-performance high-pressure type Temperature: 10~30℃ Channel diameter (inner diameter) between mixers: 1 mm Material of flow passage between mixers: "Teflon" (registered trademark) Mixer shape: T-shaped Mixer material: "Teflon" (registered trademark) Mixer channel diameter: 1mm.

[0095] (Process 1A) A 0.2 M 1,3-dibromobenzene / tetrahydrofuran solution was fed into the flow channel from server A at a flow rate of 5.0 ml / min, and a 0.2 M n-butyllithium / n-hexane solution was fed into the flow channel from server B at a flow rate of 4.6 ml / min, and the reaction was carried out in the first T-mixer. The flow rate of the reactants was 9.6 ml / min.

[0096] (Process 2A) Two seconds after the first T-mixer, a 0.2 M 2-phenyl-1,10-phenanthroline / tetrahydrofuran solution was introduced from Server C into the flow channel at a flow rate of 4.2 ml / min, and reacted in the second T-mixer. The flow rate of the reactant was 13.8 ml / min.

[0097] (Process 3A) Four seconds after leaving the second T-mixer section, a 0.2 M n-butyllithium / n-hexane solution was flowed into the flow channel from server D at a flow rate of 4.6 ml / min, and reacted in the third T-mixer section. The reactant flow rate was 18.4 ml / min.

[0098] (Process 4A) Two seconds after the third T-mixer, a 0.2 M 2-phenyl-1,10-phenanthroline / tetrahydrofuran solution was introduced from Server E into the flow channel at a flow rate of 4.2 ml / min, and reacted in the fourth T-mixer. The flow rate of the reactant was 22.6 ml / min.

[0099] (Step 5A) Two seconds after the fourth T-mixer, a 0.2 M iodine / tetrahydrofuran solution was introduced into the flow channel from Server F at a flow rate of 4.2 ml / min, and reacted in the fifth T-mixer. The flow rate of the reactant was 26.8 ml / min. Ten seconds after the fifth T-mixer, the reactant was sampled in a flask. However, the sample was collected one minute after the pump started.

[0100] Next, the resulting suspension of the reaction product was filtered using a Kiriyama funnel (filter paper mesh: 4 μm), and the filtered residue was dried at 80°C to obtain 5.1 g of a crude product of a phenanthroline derivative having a structure represented by the following structural formula (5).

[0101] [ka]

[0102] Subsequently, (Step 6A) was carried out by the following method (batch method).

[0103] (Process 6A) The crude product of the phenanthroline derivative having the structure represented by the structural formula (5) obtained in (Step 5A) was washed with toluene by heating and slurry, then recrystallized from an anisole / toluene solution, and washed with tetrahydrofuran / methanol by heating and slurry. The crystals were purified by a 1.0×10 filtration method using an oil diffusion pump. -3 Purification by sublimation was carried out at 320° C. under a pressure of 1000 kJ / cm 2 or less, to obtain 3.9 g of a phenanthroline derivative having the structure represented by the structural formula (5).

[0104] The obtained phenanthroline derivative was evaluated by the above-mentioned method, and the results are shown in Table 1.

[0105] Example 2 3.6 g of a phenanthroline derivative having a structure represented by the structural formula (5) was obtained in the same manner as in Example 1, except that in (Step 2A) and (Step 4A), 1,10-phenanthroline was used instead of 2-phenyl-1,10-phenanthroline, and (Step 5A) was changed to the following (Step 5A-1) to (Step 5A-3).

[0106] (Step 5A-1) Two seconds after the fourth T-mixer, a 0.2 M iodine / tetrahydrofuran solution was introduced into the flow channel from Server F at a flow rate of 4.2 ml / min, and reacted in the fifth T-mixer. The flow rate of the reactant was 26.8 ml / min.

[0107] (Step 5A-2) Ten seconds after the fifth T-mixer, a 0.2 M phenyllithium / dibutyl ether solution was introduced into the flow channel from server G at a flow rate of 8.4 ml / min, and reacted in the fifth T-mixer. The flow rate of the reactant was 35.2 ml / min.

[0108] (Step 5A-3) Two seconds after the sixth T-mixer, a 0.2 M iodine / tetrahydrofuran solution was introduced into the flow channel from Server H at a flow rate of 4.2 ml / min, and reacted in the seventh T-mixer. The flow rate of the reactant was 39.4 ml / min. Ten seconds after the seventh T-mixer, the reactant was sampled in a flask. However, the reaction solution was sampled one minute after the pump started.

[0109] The obtained phenanthroline derivative was evaluated by the above-mentioned method, and the results are shown in Table 1.

[0110] Example 3 (Step 1B) to (Step 5B) were carried out by a flow reaction using the same apparatus as in Example 1.

[0111] (Process 1B) A 0.2 M bromobenzene / tetrahydrofuran solution was fed from server A to the flow channel at a flow rate of 5.0 ml / min, and a 0.2 M n-butyllithium / n-hexane solution was fed from server B to the flow channel at a flow rate of 4.6 ml / min, and the reaction was carried out in the first T-mixer. The flow rate of the reactants was 9.6 ml / min.

[0112] (Process 2B) Two seconds after leaving the first T-mixer, a 0.2 M 1,10-phenanthroline / tetrahydrofuran solution was introduced from server C into the flow channel at a flow rate of 4.2 ml / min, and reacted in the second T-mixer. The flow rate of the reactant was 13.8 ml / min.

[0113] (Process 3B) Two seconds after the second T-mixer, a 0.2 M iodine / tetrahydrofuran solution was pumped from Server D into the flow channel at a flow rate of 4.2 ml / min, and reacted in the third T-mixer. The flow rate of the reactant was 18.0 ml / min. Ten seconds after the third T-mixer, the reactant was sampled in a flask. However, the sample was collected one minute after the pump started.

[0114] The resulting suspension was then filtered using a Kiriyama funnel (filter paper mesh: 4 μm), and the residue was dried at 80° C. to obtain 5.1 g of a crude product of 2-phenyl-1,10-phenanthroline.

[0115] Subsequently, (Step 4B) was carried out by the following method (batch method).

[0116] (Process 4B) The crude product of 2-phenyl-1,10-phenanthroline obtained in (Step 3B) was washed with toluene by heating and slurry, then recrystallized from an anisole / toluene solution, and washed with tetrahydrofuran / methanol by heating and slurry. The crystals were purified by filtration using an oil diffusion pump. -3 Purification by sublimation was carried out at 320°C under a pressure of 100 Pa or less, to obtain 4.0 g of 2-phenyl-1,10-phenanthroline.

[0117] The obtained phenanthroline derivative was evaluated by the above-mentioned method, and the results are shown in Table 1.

[0118] (Comparative Example 1) Steps 1A to 4A were carried out in the same manner as in Example 1, and the reaction product was collected from the fourth T-mixer in a flask 4 seconds later. However, the reaction product was collected 1 minute after the pump started operating. Subsequently, a crude product of the phenanthroline derivative having the structure represented by the structural formula (5) was obtained by the following method (batchwise) in Step 5A'.

[0119] (Step 5A') The internal temperature of the flask was maintained at 0 to 5°C using ice water, and 50 ml of the reaction product solution obtained in (Step 4A) was collected. Next, the reaction product solution was stirred while maintaining the internal temperature of the flask at 0 to 5°C, and 5 ml of HO was added to quench the mixture. Next, 50 ml of dichloromethane was added to the quenched solution to extract the reaction product. 50 ml of a 0.2 M iodine / tetrahydrofuran solution was added to this extract solution while maintaining the internal temperature of the flask at 30°C or less, and then the mixture was stirred for 15 minutes to oxidize the reaction product. The resulting oxide suspension was then filtered using a Kiriyama funnel (filter paper mesh: 4 μm), and the residue was dried at 80°C to obtain 5.3 g of a crude product of the phenanthroline derivative having the structure represented by the structural formula (5).

[0120] Next, (Step 6A) was carried out in the same manner as in Example 1 to obtain 3.8 g of a phenanthroline derivative having a structure represented by structural formula (5).

[0121] The obtained phenanthroline derivative was evaluated by the above-mentioned method, and the results are shown in Table 1.

[0122] (Comparative Example 2) Steps 1A to 4A were carried out in the same manner as in Example 2, and the reaction product was collected from the fourth T-mixer in a flask 4 seconds later. However, the reaction product was collected 1 minute after the pump started operating. Subsequently, a crude product of the phenanthroline derivative having the structure represented by structural formula (5) was obtained by the following methods (batchwise) of Steps 5A'-1 to 5A'-3.

[0123] (Process 5A'-1) The internal temperature of the flask was maintained at 0 to 5°C using ice water, and 50 ml of the reaction product solution obtained in (Step 4A) was collected. Next, the reaction product solution was stirred while maintaining the internal temperature of the flask at 0 to 5°C, and 5 ml of HO was added to quench it. Next, 50 ml of dichloromethane was added to the quenched solution to extract the reaction product. 50 ml of a 0.2 M iodine / tetrahydrofuran solution was added to this extract solution while maintaining the internal temperature of the flask at 30°C or less, and then the mixture was stirred for 15 minutes to oxidize it. Next, the resulting oxide suspension was filtered using a Kiriyama funnel (filter paper mesh: 4 μm), and the filtered residue was dried at 80°C.

[0124] (Process 5A'-2) Next, the reaction product obtained in (Step 5A'-1) was placed in a 100 ml four-neck flask purged with nitrogen gas. While stirring, the internal temperature of the flask was maintained at 0 to 5°C. 40 ml of a 1.6 M phenyllithium / dibutyl ether solution was added, and the mixture was stirred for an additional 2.5 hours. Subsequently, while stirring, the internal temperature of the flask was maintained at 0 to 5°C. 10 ml of HO was added to quench the mixture.

[0125] (Process 5A'-3) Next, ice water was used to maintain the internal temperature of the flask at 0 to 5°C, and 40 ml of the reaction product solution obtained in (Step 5A'-2) was collected. Next, while maintaining the internal temperature of the flask at 0 to 5°C, the reaction product solution was stirred, and 4 ml of HO was added to quench the mixture. Next, 40 ml of dichloromethane was added to the quenched solution to extract the reaction product. 50 ml of a 0.2 M iodine / tetrahydrofuran solution was added to this extract solution while maintaining the internal temperature of the flask at 30°C or less, and then the mixture was stirred for 15 minutes to oxidize the reaction product. Next, the resulting oxide suspension was filtered using a Kiriyama funnel (filter paper mesh: 4 μm), and the residue was dried at 80°C to obtain 2.1 g of a crude product of a phenanthroline derivative having the structure represented by the structural formula (5).

[0126] Next, (Step 6A) was carried out in the same manner as in Example 2 to obtain 1.9 g of a phenanthroline derivative having a structure represented by the structural formula (5). The obtained phenanthroline derivative was evaluated by the above-mentioned method, and the results are shown in Table 1.

[0127] [Table 1]

Claims

1. A method for producing a phenanthroline derivative having a structure represented by the following general formula (1): (Step 1A) reacting a dihalogenated benzene with an organolithium reagent; (Step 2A) reacting the lithiation reaction product of Step 1A with a compound having a structure represented by the following general formula (2): (Step 3A) reacting the reaction product of Step 2A with an organolithium reagent; (Step 4A) a step of reacting the lithiation reaction product of Step 3A with a compound having a structure represented by the following general formula (2): (Step 5A) a step of oxidizing the reaction product of Step 4A with iodine to obtain a crude product of a phenanthroline derivative; (Step 6A) a step of recrystallizing the crude product of the phenanthroline derivative obtained in Step 5A and further sublimating it; The method for producing a phenanthroline derivative comprises the steps of (Step 1A) to (Step 5A) in this order, and continuously carrying out at least the steps from (Step 1A) to (Step 5A). 【Chemistry 1】 (In the above general formula (1), R2 to R13 may be the same or different and represent a hydrogen atom, a substituted or unsubstituted aryl group, a heteroaryl group, an alkyl group, a cycloalkyl group, an alkoxy group, an aryloxy group, an alkenyl group, a cycloalkenyl group, an alkynyl group, an alkylthio group, an arylthio group, or a cyano group. R1 and R14 may be the same or different and represent a substituted or unsubstituted aryl group, a heteroaryl group, an alkyl group, or a cycloalkyl group.) 【Chemistry 2】 (In the above general formula (2), R15 to R21 may be the same or different and represent a hydrogen atom, a substituted or unsubstituted aryl group, a heteroaryl group, an alkyl group, a cycloalkyl group, an alkoxy group, an aryloxy group, an alkenyl group, a cycloalkenyl group, an alkynyl group, an alkylthio group, an arylthio group, or a cyano group.)

2. In the (Step 2A) and / or (Step 4A), a compound in which R15 in general formula (2) is a hydrogen atom is used, The step 5A comprises at least (Step 5A-1) a step of oxidizing the reaction product of Step 4A with iodine; (Step 5A-2) a step of reacting the reaction product of Step 5A-1 with phenyllithium; (Step 5A-3) A step of oxidizing the reaction product of Step 5A-2 with iodine to obtain a crude product of a phenanthroline derivative.

2. The method for producing a phenanthroline derivative according to claim 1, wherein the compound is a phenanthroline derivative having the following structure in this order:

3. 2. The method for producing a phenanthroline derivative according to claim 1, wherein the dihalogenated benzene is 1,3-dihalogenated benzene, and the compound having a structure represented by general formula (2) is 2-phenyl-1,10-phenanthroline.

4. 3. The method for producing a phenanthroline derivative according to claim 2, wherein the dihalogenated benzene is 1,3-dihalogenated benzene, and the compound having a structure represented by general formula (2) is 1,10-phenanthroline.

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