Method for producing aromatic amino compound

Abstract

Provided is a new method for producing an aromatic amino compound that is useful as a production intermediate for electronic materials and pharmaceutical and agricultural chemicals, and that has, at a moiety other than an aromatic ring, at least one multiple bond selected from carbon-carbon, carbon-nitrogen, and carbon-oxygen.　This method for producing an aromatic amino compound is characterized by catalytically reducing an aromatic nitro compound having, at a moiety other than an aromatic ring, at least one multiple bond selected from carbon-carbon, carbon-nitrogen, and carbon-oxygen, by using a Pt / C catalyst in the presence of at least one phosphorus compound (A) selected from the group consisting of phosphorus compounds represented by formula (1), phosphorus compounds represented by formula (2), and phosphorus compounds represented by formula (3).　(1): P(R1)3 (2): PO(R2)3 (3): (R3)2P-R4-P(R3)2 (The meaning of each symbol in formulae (1)-(3) is as defined in the description.)

Description

Method for producing aromatic amino compounds

[0001] The present invention relates to a method for producing aromatic amino compounds which are useful as intermediates in the production of agricultural chemicals and electronic materials and which have at least one multiple bond selected from carbon-carbon, carbon-nitrogen, and carbon-oxygen bonds in a moiety other than the aromatic ring.

[0002] It is known that aromatic amino compounds can be produced by reducing aromatic nitro compounds. On the other hand, when an amino compound is produced by reducing an aromatic nitro compound having at least one multiple bond selected from carbon-carbon, carbon-nitrogen, and carbon-oxygen in a portion other than the aromatic ring, the multiple bond is also reduced depending on the conditions. Therefore, it is generally difficult to reduce only the nitro group to an amino group while leaving the multiple bond intact. Therefore, methods for selectively reducing only the nitro group of an aromatic nitro compound to an amino group have been sought.

[0003] As an example of a document describing such a reduction reaction, Patent Document 1 discloses a method for producing a substituted aromatic amino compound containing at least one carbon-carbon, carbon-nitrogen, or carbon-oxygen multiple bond in the aromatic moiety or side chain by catalytic hydrogenation of the corresponding substituted aromatic nitro compound in the presence of a modified noble metal catalyst, in which rhodium, ruthenium, iridium, platinum, or palladium having an oxidation state of less than 5 and modified with an inorganic or organic phosphorus compound is used as the noble metal catalyst. Also, Patent Document 2 proposes a method for selectively hydrogenating an aromatic nitro compound to an aromatic amino compound using a Pt / C catalyst poisoned with a trace amount of iron.

[0004] Patent Publication No. 2001-501201 German Patent Application Publication No. 102011003590

[0005] Thus, methods for selectively reducing only the nitro group of an aromatic nitro compound to an amino group have been proposed, but a method for reducing only the nitro group of an aromatic nitro compound to an amino group with higher selectivity and without impairing the reaction rate is desired. In view of the above, an object of the present invention is to provide a novel method for producing an aromatic amino compound, which is useful as a production intermediate for agricultural chemicals and electronic materials, and which can reduce to an amino group with higher selectivity and without impairing the reaction rate.

[0006] In view of these circumstances, the present inventors have conducted extensive research and have discovered a method for selectively reducing only the nitro group of an aromatic nitro compound having at least one multiple bond selected from carbon-carbon, carbon-nitrogen, and carbon-oxygen in a portion other than the aromatic ring by catalytic reduction with a specific noble metal supported catalyst in the presence of a specific phosphorus compound, thereby arriving at the present invention. That is, the present inventors have found that the above-mentioned problems can be solved by the following configuration.

[0007] [1] A method for producing an aromatic amino compound, comprising catalytically reducing an aromatic nitro compound having at least one multiple bond selected from carbon-carbon, carbon-nitrogen, and carbon-oxygen in a portion other than the aromatic ring with a Pt / C catalyst in the presence of at least one phosphorus compound (A) selected from the group consisting of phosphorus compounds represented by the following formula (1), phosphorus compounds represented by the following formula (2), and phosphorus compounds represented by the following formula (3): P(R １ ) ３ (1) (In formula (1), a plurality of R １ each independently represents a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, an aryl group having 6 to 24 carbon atoms, an aryloxy group having 6 to 24 carbon atoms, a cycloalkyl group having 3 to 18 carbon atoms, or a cycloalkoxy group having 3 to 18 carbon atoms, which may have a substituent.) PO(R ２ ) ３ (2) (In formula (2), a plurality of R ２each independently represents a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, an aryl group having 6 to 24 carbon atoms, an aryloxy group having 6 to 24 carbon atoms, a cycloalkyl group having 3 to 18 carbon atoms, or a cycloalkoxy group having 3 to 18 carbon atoms, which may have a substituent.) (R ３ ) ２ P-R ４ -P(R ３ ) ２ (3) (In formula (3), a plurality of R ３ each independently represents an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, an aryl group having 6 to 24 carbon atoms, an aryloxy group having 6 to 24 carbon atoms, a cycloalkyl group having 3 to 18 carbon atoms, or a cycloalkoxy group having 3 to 18 carbon atoms, which may have a substituent. ４ represents an alkylene group having 1 to 18 carbon atoms, an alkenylene group having 1 to 18 carbon atoms, an alkylenedioxy group having 1 to 18 carbon atoms, an arylene group having 6 to 24 carbon atoms, an arylene group having 6 to 24 carbon atoms, a cycloalkylene group having 3 to 18 carbon atoms, or a cycloalkylenedioxy group having 3 to 18 carbon atoms, which may have a substituent.) [2] The phosphorus compound (A) is P(OMe) ３ , or P(OEt) ３ [3] The method for producing an aromatic amino compound according to [1] or [2], wherein the amount of the phosphorus compound (A) used is 5 to 50 mol % based on the amount of the aromatic amino compound. [4] The method for producing an aromatic amino compound according to any one of [1] to [3], wherein the aromatic nitro compound is represented by any one of the structures of the following formulas (1) to (3): (In the formula, R ５ , R ６ , R ８ , R ９ each independently represents a single bond or a divalent group, R ７represents a hydrogen atom or a monovalent group, and n represents an integer of 1 or 2.) [5] The method for producing an aromatic amino compound according to any one of [1] to [4], wherein the amount of platinum supported on the Pt / C catalyst is 0.5 to 5 wt % based on the total weight of the Pt / C catalyst. [6] The method for producing an aromatic amino compound according to any one of [1] to [5], wherein the Pt / C catalyst is a Pt / C catalyst poisoned with iron. [7] The method for producing an aromatic amino compound according to any one of [1] to [6], wherein the amount of the Pt / C catalyst used is 1 to 20 wt % based on the aromatic nitro compound. [8] The method for producing an aromatic amino compound according to any one of [1] to [7], wherein the reaction temperature in the catalytic reduction is 0 to 100°C and the reaction time is 0.5 to 20 hours. [9] The method for producing an aromatic amino compound according to any one of [1] to [8], further comprising the coexistence of a vanadium compound.

[10] The vanadium compound is VO(acac) ２

[11] The method for producing an aromatic amino compound according to [9] or

[10] , wherein the amount of the vanadium compound used is 0.1 to 1.0 mol % relative to the aromatic nitro compound.

[0008] According to the production method of the present invention, only the nitro group of an aromatic nitro compound (hereinafter also referred to simply as "compound (DN)") having at least one multiple bond selected from carbon-carbon, carbon-nitrogen, and carbon-oxygen in a moiety other than the aromatic ring can be selectively reduced without impairing the reaction rate. Therefore, aromatic amino compounds having at least one multiple bond selected from carbon-carbon, carbon-nitrogen, and carbon-oxygen in a moiety other than the aromatic ring, which are useful as production intermediates for agricultural chemicals and electronic materials, can be produced inexpensively and efficiently.

[0009] Throughout this specification, the following terms and abbreviations have the following meanings. A numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the upper and lower limits. In numerical ranges described in stages in this specification, the upper or lower limit described in a certain numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Furthermore, in numerical ranges described in this specification, the upper or lower limit described in a certain numerical range may be replaced with a value shown in the examples. Me represents a methyl group, Et represents an ethyl group, Pr represents a propyl group, Bu represents a butyl group, n- represents normal, t- represents tertiary, o- represents ortho, Cy represents a cyclohexyl group, Ph represents a phenyl group, Bn represents a benzyl group, Tol represents a tolyl group, and acac represents acetylacetonate.

[0010]

[0023] The method for producing an aromatic amino compound of the present invention will be described below. In explaining the details of the method for producing an aromatic amino compound of the present invention, specific examples will be given, but the present invention is not limited to the following content and can be carried out with appropriate modifications without departing from the spirit of the present invention.

[0011] The production method of the present invention includes, for example, a method for producing an aromatic amino compound represented by the following reaction formula 1. In the formula, L represents a single bond or a divalent group, and X represents CR １１ Y represents O, NR １２ or CR １３ R １４ represents R １１ , R １２ , R １３ and R １４ each independently represents a hydrogen atom or a monovalent group, provided that R １１ , R １２ , R １３ and R １４ Alternatively, X and Y may not be bonded to each other, but may form a triple bond. １ are each independently defined as above.

[0012] Furthermore, when the bond between X and Y is a double bond, X and Y may combine to form a cyclic structure such as a 5-membered or 6-membered ring, and specific examples of the cyclic structure include cyclic olefins such as cyclohexene, cyclohexadiene, pyran, dihydropyran, dihydrofuran, cyclohexen-1-one, dihydropyrrole, dihydropyridine, and tetrahydropyridine. That is, when compound (DN), which is an aromatic nitro compound, is a compound having, for example, cyclohexene as the cyclic structure, it is a compound having the following structure: (In the formula, L represents a single bond or a divalent group.)

[0013] Furthermore, when the bond between X and Y is a double bond, Y may be bonded to a benzene ring substituted with a nitro group, and specific examples include compounds having the following structures:

[0014] The present invention provides a method for producing an aromatic amino compound by catalytically reducing an aromatic nitro compound having at least one multiple bond selected from carbon-carbon, carbon-nitrogen, and carbon-oxygen in a moiety other than the aromatic ring, with a Pt / C catalyst in the presence of at least one phosphorus compound (A) selected from the group consisting of phosphorus compounds represented by the following formula (1), phosphorus compounds represented by the following formula (2), and phosphorus compounds represented by the following formula (3):

[0015] The aromatic nitro compound used in the present invention is an aromatic nitro compound having at least one multiple bond selected from carbon-carbon, carbon-nitrogen, and carbon-oxygen in a portion other than the aromatic ring. As the aromatic nitro compound, an aromatic mononitro compound or an aromatic dinitro compound is preferred. Among the above multiple bonds, an α,β-unsaturated carbonyl group is preferred. Examples of aromatic nitro compounds having an α,β-unsaturated carbonyl group as a multiple bond include compounds (I) to (III) having the following structures:

[0016] (In the formula, R ５ , R ６ , R ８ , R ９each independently represents a single bond or a divalent group, R ７ represents a hydrogen atom or a monovalent group, R １０ , R １１ , R １２ , R １３ , R １４ , R １５ , R １６ , R １７ , R １８ , R １９ each independently represents a hydrogen atom or a methyl group, and n represents an integer of 1 or 2.

[0017] As the compounds represented by the above formulas (I) to (III), the following compounds (1) to (3) are preferred. (In the above formula, R ５ , R ６ , R ８ , R ９ each independently represents a single bond or a divalent group, R ７ represents a hydrogen atom or a monovalent group, and n represents an integer of 1 or 2.

[0018] The above R ５ , R ６ , R ８ , R ９ The divalent group in the formula (I) includes an unsubstituted or fluorine-substituted alkylene group having 1 to 20 carbon atoms. ２ -or-CF ２ - may be replaced by a group selected from the group consisting of -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, a divalent carbocyclic ring, and a divalent heterocyclic ring (with the proviso that groups selected from these groups are not adjacent to each other), and among these, an unsubstituted alkylene group having 1 to 6 carbon atoms (the -CH ２ Preferably, - may be replaced by a group selected from -O-, -COO-, -OCO-, -NHCO-, -CONH- and -NH- (provided that groups selected from this group are not adjacent to each other).

[0019] The above R ７The monovalent group in the above formula (I) includes an unsubstituted or fluorine-substituted alkyl group having 1 to 20 carbon atoms. ２ -or-CF ２ - may be replaced by a group selected from the group consisting of -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, a divalent carbocyclic ring, and a divalent heterocyclic ring (with the proviso that groups selected from these groups are not adjacent to each other), and among these, an unsubstituted alkyl group having 1 to 6 carbon atoms (with -CH ２ Preferably, - may be replaced by a group selected from -O-, -COO-, -OCO-, -NHCO-, -CONH- and -NH- (provided that groups selected from this group are not adjacent to each other).

[0020] The phosphorus compound used in the present invention includes at least one phosphorus compound (A) selected from the group consisting of phosphorus compounds represented by the following formula (1), phosphorus compounds represented by the following formula (2), and phosphorus compounds represented by the following formula (3): P(R １ ) ３ (1) (In formula (1), a plurality of R １ each independently represents a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, an aryl group having 6 to 24 carbon atoms, an aryloxy group having 6 to 24 carbon atoms, a cycloalkyl group having 3 to 18 carbon atoms, or a cycloalkoxy group having 3 to 18 carbon atoms, which may have a substituent.) PO(R ２ ) ３ (2) (In formula (2), a plurality of R ２ each independently represents a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, an aryl group having 6 to 24 carbon atoms, an aryloxy group having 6 to 24 carbon atoms, a cycloalkyl group having 3 to 18 carbon atoms, or a cycloalkoxy group having 3 to 18 carbon atoms, which may have a substituent.) (R ３ ) ２ P-R ４ -P(R ３ ) ２(3) (In formula (3), a plurality of R ３ each independently represents an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, an aryl group having 6 to 24 carbon atoms, an aryloxy group having 6 to 24 carbon atoms, a cycloalkyl group having 3 to 18 carbon atoms, or a cycloalkoxy group having 3 to 18 carbon atoms, which may have a substituent. ４ represents an alkylene group having 1 to 18 carbon atoms, an alkenylene group having 1 to 18 carbon atoms, an alkylenedioxy group having 1 to 18 carbon atoms, an arylene group having 6 to 24 carbon atoms, an arylene group having 6 to 24 carbon atoms, a cycloalkylene group having 3 to 18 carbon atoms, or a cycloalkylenedioxy group having 3 to 18 carbon atoms, which may have a substituent.

[0021] R in the above formula (1) １ Specific examples of the aryl group include methyl, ethyl, normal propyl (n-Pr), isopropyl (i-Pr), normal butyl (n-Bu), tertiary butyl (t-Bu), phenyl (Ph), benzyl (Bn), methoxy (OMe), ethoxy (OEt), normal propyloxy (On-Pr), normal butyloxy (On-Bu), phenoxy (OPh), and benzyloxy. 、 OMe, OEt, On-Bu and OPh are preferred, and OMe and OEt are more preferred in terms of higher selectivity.

[0022] R in the above formula (2) ２ Specific examples of include hydrogen, methyl, ethyl, n-Pr, i-Pr, n-Bu, t-Bu, n-octyl, cyclohexyl, Ph, p-methylphenyl, p-methoxyphenyl, benzyl, OMe, OEt, n-propyloxy, n-butyloxy, OPh, and benzyloxy. From the viewpoint of higher selectivity, hydrogen, methyl, n-Bu, n-octyl, and Ph are preferred, and hydrogen, methyl, and Ph are more preferred.

[0023] R in the above formula (3) ３Specific examples of R include hydrogen, methyl, ethyl, n-Pr, i-Pr, n-Bu, t-Bu, n-octyl, cyclohexyl, Ph, p-methylphenyl, p-methoxyphenyl, benzyl, OMe, OEt, n-propyloxy, n-butyloxy, OPh, and benzyloxy. Methyl, ethyl, OMe, OEt, and Ph are preferred in terms of higher selectivity, and methyl, OMe, OEt, and Ph are more preferred in terms of higher selectivity. ４ Specific examples of the alkyl group include methylene, ethylene, propylene, butylene, pentylene, hexylene, 1,2-phenylene, 1,3-phenylene, 2,2'-biphenylene, 2,2'-binaphthylene, 1,8-naphthylene, 1,8-(9,9-dimethyl)xanthenylene, and 1,1'-ferrocenylene. Of these, methylene, ethylene, propylene, butylene, 1,2-phenylene, 2,2'-biphenylene, 2,2'-binaphthylene, 1,8-naphthylene, and 1,1'-ferrocenylene are preferred, and from the viewpoint of higher selectivity, methylene, ethylene, propylene, butylene, and 2,2'-binaphthylene are more preferred.

[0024] R in the formula １ , R ２ , R ３ Examples of the substituent that may be substituted include a methyl group, an ethyl group, an i-propyl group, a t-butyl group, a phenyl group, a hydroxyl group, a methoxy group, an i-propyloxy group, a t-butyloxy group, an amino group, a dimethylamino group, a cyano group, a formyl group, a carboxy group, a sulfoxy group, a fluoro group, a chloro group, a bromo group, and an iodo group.

[0025] Specific examples of the phosphorus compound (A) include PMe ３ , PEt ３ , P(n-Pr) ３ , P(n-Bu) ３ , P(t-Bu) ３ , P(n-C ６ H １３ ) ３ , P(n-C ８ H １７ ) ３ , PCy ３ , PBn３ , PPh ３ , P(o-Tol) ３ , P(OMe) ３ , P(OEt) ３ , P(On-Pr) ３ , P(On-Bu) ３ , P(OPh) ３ , P(OBn) ３ , P(O)(n-Bu) ３ , P(O)Ph ３ , (±)-BINAP (2,2'-bis(diphenylphosphino)-1,1-binaphthyl), (+)-BINAP, (-)-BINAP, depe (1,2-bis(diethylphosphino)ethane), dppm (1,1-bis(diphenylphosphino)methane), dppe (1,2-bis(diphenylphosphino)ethane), dppp (1,3-bis(diphenylphosphino)propane), dppb (1,4-bis(diphenylphosphino)butane), dppbz (1,2-bis(diphenylphosphino)benzene), dppf (1,1'-bis(diphenylphosphino)ferrocene), Xantphos, and the like.

[0026] Among them, P(n-Bu) ３ , PPh ３、 P (OMe) ３ , P(OEt) ３ , P(On-Bu) ３ , P(OPh) ３ is preferred, and P(OMe) is preferred because of its higher selectivity. ３ , P(OEt) ３ is more preferred.

[0027] In the present invention, the amount of the phosphorus compound (A) used is preferably 50 mol % or less, more preferably 35 mol % or less, based on the amount of the aromatic nitro compound (DN) in terms of ease of removal after the reaction, and is preferably 5 mol % or more, more preferably 10 mol % or more in terms of excellent selectivity.

[0028] In this reaction, the amount of the Pt / C catalyst used is preferably 1% by weight or more, more preferably 3% by weight or more, and is preferably 20% by weight or less, more preferably 10% by weight or less, relative to the amount of the aromatic nitro compound (DN).

[0029] The amount of platinum carried in the Pt / C catalyst is preferably 0.5 to 5% by weight, more preferably 1 to 5% by weight, based on the total weight of the Pt / C catalyst.

[0030] In this reaction, the Pt / C catalyst is preferably poisoned with S, Cu, V, or Fe, and more preferably poisoned with Fe. The amount of Fe used for poisoning is preferably 0.05 wt % or more, more preferably 0.1 wt % or more, based on the total weight of the Pt / C catalyst poisoned with Fe, from the viewpoint of suppressing side reactions, and is preferably 1.0 wt % or less, more preferably 0.5 wt % or less, from the viewpoint of not reducing catalytic activity.

[0031] In this reaction, it is preferable to further coexist a vanadium compound from the viewpoint of suppressing the formation of azoxy compounds. Such a vanadium compound is VO(acac) ３ , VO(acac) ２ , N.H. ４ VO ３ , V ２ O ５ , VOCl ３ , VCl ６ , [VO(SCN) ４ ] ２－ , VOSO ４ , LiVO ３ , NaVO ３ , K.V.O. ３ , VCl ３ is preferred, and VO(acac) ２ is more preferred.

[0032] In this reaction, the amount of the vanadium compound used is preferably 1.0 mol % or less, more preferably 0.2 mol % or less, relative to compound (DN), since too much vanadium compound is likely to remain in the product. Furthermore, the amount of the vanadium compound used is preferably 0.1 mol % or more, from the viewpoint of sufficiently suppressing the production of azoxy compounds.

[0033] This reaction may be carried out in a solvent. Any reaction solvent can be used as long as it is stable, inert, and does not interfere with the reaction under the reaction conditions. Examples of reaction solvents include water, alcohols, amines, aprotic polar organic solvents (DMF (dimethylformamide), DMSO (dimethyl sulfoxide), DMAc (dimethylacetamide), NMP (N-methylpyrrolidone), etc.), ethers (Et ２ O, i-Pr ２ Examples of solvents that can be used include: toluene (Tetane, TBME (tert-butyl methyl ether), CPME (cyclopentyl methyl ether), THF (tetrahydrofuran), dioxane, etc.); aliphatic hydrocarbons (pentane, hexane, heptane, petroleum ether, etc.); aromatic hydrocarbons (benzene, toluene, xylene, mesitylene, chlorobenzene, dichlorobenzene, nitrobenzene, tetralin, etc.); halogenated hydrocarbons (chloroform, dichloromethane, carbon tetrachloride, dichloroethane, etc.); lower fatty acid esters (methyl acetate, ethyl acetate, butyl acetate, methyl propionate, etc.); and nitriles (acetonitrile, propionitrile, butyronitrile, etc.). These solvents can be appropriately selected taking into consideration the ease of reaction, etc., and can be used alone or in combination of two or more. In some cases, the above solvents can be used as water-free solvents by using an appropriate dehydrating agent or drying agent.

[0034] The reaction temperature during catalytic reduction is usually −90° C. to 200° C., and preferably 0° C. to 100° C. The reaction time during catalytic reduction is usually 0.05 hours to 100 hours, preferably 0.5 hours to 20 hours, and more preferably 0.5 hours to 10 hours. The reaction pressure during catalytic reduction is usually atmospheric pressure to 10 MPaG, and preferably atmospheric pressure to 0.8 MPaG.

[0035] The present invention will be described in more detail below with reference to examples, but the interpretation of the present invention is not limited to these examples. The analytical apparatus and analytical conditions used in the examples are as follows.

[0036] １ H-NMR: Apparatus: ECZ (400 MHz) manufactured by JEOL Ltd. Measurement solvent: CDCl ３ Reference material: Tetramethylsilane (TMS) (TMS １ The δ value of H is set to 0.0 ppm.)

[0037] HPLC: Apparatus: HPLC, Shimadzu Corporation LC-20AD Column: Inertsil ODS-3 (GL Science), 5 μm Φ4.6 × 250 mm Column temperature: 40 °C Eluent: (A) acetonitrile / (B) 50 mM potassium phosphate buffer (pH = 7) A / B = 35 / 65 (0 to 10 min) - 60 / 40 (13 to 30 min) (v / v) Flow rate: 1.0 mL / min Detection method: UV (254 nm) Data collection time: 30 min

[0038] [Synthesis Examples of Aromatic Amino Compounds] <Synthesis Example 1> Preparation of 2-(3,5-diaminobenzoyloxy)ethyl methacrylate (Compound DA-1)

[0039]

[0040] The nitro compounds used here are known compounds and can be synthesized according to known methods described in the literature. For example, 2-(3,5-dinitrobenzoyloxy)ethyl methacrylate can be obtained by reacting it according to the method described in Japanese Patent No. 5,560,715.

[0041] Synthesis Example 1-a-1: 2-(3,5-dinitrobenzoyloxy)ethyl methacrylate (5.00 g, 15.4 mmol), toluene (50.0 g), triethyl phosphite (0.512 g, 3.08 mmol), 1 wt % Pt / C catalyst (55.0 wt % hydrous, 0.556 g) poisoned with 0.2 wt % iron, and vanadium oxide bisacetylacetonate (8.94 mg, 30.8 μmmol) were placed in a 200 mL pressure vessel and stirred at 40° C. for 4 hours under a hydrogen atmosphere at a gauge pressure of 0.60 MPa. HPLC analysis of the reaction solution revealed that the HPLC relative area percentage of DA-1 was 98.8%, the reaction yield was 100%, and the over-reduced product (DA-1′) was not detected. After the reaction was completed, ethyl acetate (20.0 g) was added, the catalyst was filtered, and the residue was washed twice with ethyl acetate (5.00 g). Water (20.0 g) was added to the filtrate, and after stirring, the operation of removing the aqueous layer was repeated twice, and then the organic layer was concentrated to 41.2 g, toluene (50.0 g) was added, and again concentrated to 41.2 g, and then cooled to 0 ° C., and the precipitated crystals were filtered, and the crystals were washed twice with toluene (15.0 g), and then washed twice with water (5.0 g), and dried under reduced pressure at 40 ° C. to obtain powder crystals (DA-1) (yield 3.44 g, yield 86.5%). As a result of measuring the HPLC of the obtained crystals, the HPLC relative area percentage of DA-1 was 100.0% and the over-reduced form (DA-1') was not detected.

[0042] １ H-NMR (CDCl ３ ):δ 6.77 (d, J=2.4Hz, 2H, Ar), 6.19 (dd, J=2.4Hz, 2.2Hz, 1H, =CH), 6. 14 (br, 1H, Ar), 5.59 (dd, J=2.4Hz, 2,2Hz, 1H, =CH), 4.48 (m, 4H, CH ２ CH ２ ), 3.59 (br, 4H, NH ２ ), 1.95 (s, 3H, Me).

[0043] Comparative Synthesis Example: 2-(3,5-dinitrobenzoyloxy)ethyl methacrylate (2.00 g, 6.17 mmol), toluene (20.0 g), a 50 wt % aqueous solution of hypophosphorous acid (0.163 g, 1.23 mmol), and 1 wt % Pt / C (55.0 wt % hydrous, 0.444 g) poisoned with 0.2 wt % iron were added to a 200 mL pressure vessel, and the mixture was stirred at 40° C. under a hydrogen atmosphere at a gauge pressure of 0.60 MPa. 6 hours after the start of stirring, HPLC analysis of the reaction solution revealed that the reaction was not complete, and the LC relative area percentage of DA-1 was 42.3%, and the LC relative area percentage of the over-reduced product (DA-1′) was 0.3%. Stirring was continued for a total of 24 hours, and the reaction mixture was subjected to HPLC analysis. As a result, the HPLC relative area percentage of DA-1 was 96.5%, the yield was 72%, and the HPLC relative area percentage of the over-reduced product (DA-1') was 1.0%.

[0044] The type of phosphorus compound used as an additive, the amount of DN-1 used, the amount of 1 wt% Pt / C catalyst poisoned with 0.2 wt% iron added, vanadium oxide bisacetylacetonate (VO(acac) ２ Synthesis Examples 1-a-2 to 1-a-8 were synthesized in accordance with the method described in Synthesis Example 1-a-1, except that the amount of the toluene solvent used was changed.

[0045] The types of additives used in Synthesis Examples 1-a-1 to 1-a-8 and Comparative Synthesis Examples, the amount of DN-1 used, the amount of 1 wt% Pt / C catalyst added, vanadium oxide bisacetylacetonate (VO(acac) ２ The amounts of DA-1, DA-2, DA-3, DA-4, DA-5, DA-6, DA-7, DA-8, DA-9, DA-10, DA-11, DA-12, DA-13, DA-14, DA-15, DA-16, DA-17, DA-18, DA-19, DA-20, DA-21, DA-22, DA-23, DA-24, DA-25, DA-26, DA-27, DA-28, DA-2 ...

[0046]

[0047] As shown in Table 1, in Synthesis Examples 1-a-1 to 1-a-8, it was found that catalytic reduction using a Pt / C catalyst in the presence of phosphorus compound (A) enabled only the nitro group of an aromatic nitro compound to be reduced to an amino group with high selectivity and in a short reaction time, i.e., without impairing the reaction rate.

[0048] Synthesis Example 2: Preparation of (E)-4-(6-(methacryloyloxy)hexyloxy)cinnamic acid (2-(2,4-diaminophenyl)ethyl) ester (Compound DA-2)

[0049]

[0050] The nitro compounds used here are known compounds and can be synthesized according to known methods described in the literature. For example, (E)-4-(6-(methacryloyloxy)hexyloxy)cinnamic acid (2-(2,4-dinitrophenyl)ethyl) ester can be obtained by reacting according to the method described in Japanese Patent No. 6733552.

[0051] Synthesis Example 2 To a 200 mL pressure vessel were added (E)-4-(6-(methacryloyloxy)hexyloxy)cinnamic acid (2-(2,4-dinitrophenyl)ethyl) ester (2.00 g, 3.80 mmol), toluene (10.0 g), THF (10.0 g), triethyl phosphite (0.200 g, 1.20 mmol), and 1 wt % Pt / C (55.0 wt % hydrous, 0.444 g) poisoned with 0.2 wt % iron, and the mixture was stirred at 40°C for 2 hours under a hydrogen atmosphere at a gauge pressure of 0.30 MPa. HPLC analysis of the reaction solution revealed that the HPLC relative area percentage of DA-2 was 97.8%, the reaction yield was 96%, and no over-reduced product (DA-2') was detected. After completion of the reaction, the catalyst was filtered off, and the filter cake was washed twice with THF (2.00 g). Water (20.0 g) was added to the filtrate, and after stirring, the aqueous layer was removed. This operation was repeated twice, and the organic layer was then concentrated to 10.0 g. Toluene (20.0 g) was added, and the mixture was again concentrated to 10.0 g. The mixture was then cooled to 0°C, and the precipitated crystals were filtered. The crystals were washed twice with toluene (2.00 g), then washed twice with water (2.00 g), and dried under reduced pressure at 40°C to obtain powder crystals (DA-2) (yield: 1.40 g, 78.8%). HPLC analysis of the obtained crystals showed that the HPLC relative area percentage of DA-2 was 98.2%, and no over-reduced product (DA-2') was detected.

[0052] Synthesis Example 3: Preparation of (E)-4-aminocinnamic acid ethyl ester (compound DA-3)

[0053] As the (E)-4-nitrocinnamic acid ethyl ester, commercially available products such as those manufactured by Tokyo Chemical Industry Co., Ltd. can be used.

[0054] Synthesis Example 3: (E)-4-nitrocinnamic acid ethyl ester (2.00 g, 9.04 mmol), THF (20.0 g), triethyl phosphite (0.200 g, 1.20 mmol), and 1 wt % Pt / C catalyst (55.0 wt % hydrous, 0.444 g) poisoned with 0.2 wt % iron were added to a 200 mL pressure vessel, and the mixture was stirred at 40° C. for 3 hours under a hydrogen atmosphere at a gauge pressure of 0.30 MPa. HPLC analysis of the reaction solution revealed that the LC relative area percentage of DA-3 was 99.5%, the reaction yield was 98%, and no over-reduced product (DA-3′) was detected. After completion of the reaction, the catalyst was filtered, and the filter cake was washed twice with THF (2.00 g). The filtrate was concentrated to 10.0 g, toluene (20.0 g) was added, and the mixture was again concentrated to 10.0 g. Heptane (10.0 g) was then added, and the mixture was cooled to 0°C. The precipitated crystals were filtered, washed twice with heptane (2.00 g), and dried under reduced pressure at 40°C to obtain powder crystals (DA-3) (yield: 1.48 g, 85.7%). HPLC analysis of the obtained crystals showed that the HPLC relative area percentage of DA-3 was 99.0%, and no over-reduced product (DA-3') was detected.

[0055] Synthesis Example 4: Preparation of (E)-4-aminochalcone (compound DA-4)

[0056] As 4-nitrochalcone, commercially available products such as those manufactured by Tokyo Chemical Industry Co., Ltd. can be used.

[0057] Synthesis Example 4: 4-nitrochalcone (2.00 g, 7.90 mmol), THF (20.0 g), triethyl phosphite (0.200 g, 1.20 mmol), and 1 wt % Pt / C catalyst (55.0 wt % hydrous, 0.444 g) poisoned with 0.2 wt % iron were added to a 200 mL pressure vessel and stirred at 40°C for 3 hours under a hydrogen atmosphere at a gauge pressure of 0.30 MPa. HPLC analysis of the reaction solution revealed that the HPLC relative area percentage of DA-4 was 99.7%, the reaction yield was 100%, and no over-reduced product (DA-4') was detected. After completion of the reaction, the catalyst was filtered and the residue was washed twice with THF (2.00 g). The filtrate was then concentrated to dryness, and toluene (10.0 g) was added to the resulting crystals. After stirring at 20°C for 1 hour, the crystals were filtered, washed twice with toluene (2.00 g), and dried under reduced pressure at 40°C to obtain powder crystals (DA-4) (yield: 1.48 g, 84.2%). HPLC analysis of the resulting crystals showed that the HPLC relative area percentage of DA-4 was 97.3%, and no over-reduced product (DA-4') was detected.

[0058] Synthesis Example 5: Preparation of (E)-4-aminobenzonitrile (Compound DA-5)

[0059]

[0060] As 4-nitrobenzonitrile, commercially available products can be used (for example, those manufactured by Tokyo Chemical Industry Co., Ltd.).

[0061] Synthesis Example 5 4-Nitrobenzonitrile (2.00 g, 13.5 mmol), THF (20.0 g), triethyl phosphite (0.200 g, 1.20 mmol), and 1 wt % Pt / C catalyst (55.0 wt % hydrous, 0.444 g) poisoned with 0.2 wt % iron were placed in a 200 mL pressure vessel and stirred for 12 hours at 40° C. under a hydrogen atmosphere at a gauge pressure of 0.30 MPa. HPLC analysis of the reaction solution showed that the HPLC relative area percentage of DA-5 was 99.5%, the reaction yield was 96%, and no over-reduced product (DA-5′) was detected.

[0062] Synthesis Example 6: Preparation of 2,2-dimethyl-6-acetylamino-2H-1-benzopyran (Compound DA-6-Ac)

[0063] The 2,2-dimethyl-6-nitro-2H-1-benzopyran (DN-6) used here can be reacted in accordance with the method described in Japanese Patent No. 4258658 to obtain the compound.

[0064] 2,2-Dimethyl-6-nitro-2H-1-benzopyran (4.00 g, 19.5 mmol), toluene (40.0 g), triethyl phosphite (0.791 g, 4.76 mmol), and 1 wt% Pt / C (55.0 wt% hydrous, 0.889 g) poisoned with 0.2 wt% iron were added to a 200 mL pressure vessel and stirred at 40°C for 3 hours under a hydrogen atmosphere at a gauge pressure of 0.30 MPa. HPLC measurements were performed in the same manner as in Synthesis Example 1, except that the eluent was changed to (A) acetonitrile / (B) 10 mM ammonium acetate A / B = 50 / 50 (0-30 min). HPLC analysis of the reaction solution revealed that the HPLC relative area percentage of DA-6 was 99.7%, and the over-reduced form (DA-6') was not detected. After the reaction was completed, the catalyst was filtered, and the residue was washed twice with toluene (4.00 g). To the filtrate, acetic anhydride (2.09 g, 20.5 mmol) was added dropwise over 6 minutes at 25 ° C., and then the mixture was stirred at 25 ° C. for 1 hour. Subsequently, a 4% aqueous solution of sodium bicarbonate (40 g) was added and stirred, and the aqueous layer was removed. After that, water (20 g) was added and stirred, and the aqueous layer was removed. After repeating this operation twice, the organic layer was concentrated to 16.8 g, cooled to 0 ° C., and the precipitated crystals were filtered. The crystals were washed twice with toluene (4.00 g) and dried under reduced pressure at 40 ° C. to obtain powder crystals (DA-6-Ac) (yield 3.21 g, yield 75.8%). HPLC analysis of the obtained crystals showed that the HPLC relative area percentage of DA-6-Ac was 99.6%, and the over-reduced form (DA-6'-Ac) was not detected.

[0065] (Synthesis Example 7)

[0066] The compound (DN-7) used here can be obtained by reacting it according to the method described in Japanese Patent No. 5737291.

[0067] DN-7 (3.00 g, 7.40 mmol), THF (30.0 g), triethyl phosphite (0.600 g, 3.61 mmol), and 1 wt % Pt / C (55.0 wt % hydrous, 0.667 g) poisoned with 0.2 wt % iron were added to a 200 mL pressure vessel, and the mixture was stirred for 6 hours at 40° C. under a hydrogen atmosphere at a gauge pressure of 0.30 MPa. HPLC measurements were performed in the same manner as in Synthesis Example 1, except that the eluent was changed to (A) acetonitrile / (B) 10 mM ammonium acetate A / B = 60 / 40 (0 to 30 min). The reaction solution was analyzed by HPLC, and the HPLC relative area percentage of DA-7 was 99.9%, and the HPLC relative area percentage of the over-reduced product ((E)-DA-7', (Z)-DA-7', or DA-7") was 0.1%. After the reaction was completed, the catalyst was filtered off, and the residue was washed twice with THF (3.00 g). Toluene was removed from the filtrate by distillation at 50°C to obtain 13.6 g of a solution. 12.1 g of the obtained solution was dried under reduced pressure at 100°C to obtain a yellow glassy solid (DA-7) (yield: 2.45 g, 98.9%). １ H-NMR (CDCl ３ ): δ 6.66 (s, 1H, Ar), 6.57 (s, 2H, Ar), 4.45-4.37 (m, 2H, CH ２ ), 4.06-3.97 (m, 2H, CH ２ ), 3.40 (br, 4H, 2NH ２ ), 3.59 (br, 4H, NH ２ ), 1.50-1.39 (m, 18H, 2t-Bu).

[0068] The entire contents of the specification, claims and abstract of Japanese Patent Application No. 2023-202678 filed on November 30, 2023, and the entire contents of the specification, claims and abstract of Japanese Patent Application No. 2024-029919 filed on February 29, 2024 are cited herein and incorporated as the disclosure of the specification of the present invention.

Claims

1. A method for producing an aromatic amino compound, comprising catalytically reducing an aromatic nitro compound having at least one multiple bond selected from carbon-carbon, carbon-nitrogen and carbon-oxygen in a portion other than the aromatic ring with a Pt / C catalyst in the presence of at least one phosphorus compound (A) selected from the group consisting of phosphorus compounds represented by the following formula (1), phosphorus compounds represented by the following formula (2) and phosphorus compounds represented by the following formula (3): P(R １ ) ３ (1) (wherein in formula (1), a plurality of R １ each independently represents a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, an aryl group having 6 to 24 carbon atoms, an aryloxy group having 6 to 24 carbon atoms, a cycloalkyl group having 3 to 18 carbon atoms, or a cycloalkoxy group having 3 to 18 carbon atoms, which may have a substituent. ２ ) ３ (2) (In formula (2), a plurality of R ２ each independently represents a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, an aryl group having 6 to 24 carbon atoms, an aryloxy group having 6 to 24 carbon atoms, a cycloalkyl group having 3 to 18 carbon atoms, or a cycloalkoxy group having 3 to 18 carbon atoms, which may have a substituent.) (R ３ ) ２ P-R ４ -P(R ３ ) ２ (3) (In formula (3), a plurality of R ３ each independently represents an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, an aryl group having 6 to 24 carbon atoms, an aryloxy group having 6 to 24 carbon atoms, a cycloalkyl group having 3 to 18 carbon atoms, or a cycloalkoxy group having 3 to 18 carbon atoms, which may have a substituent. ４ represents an alkylene group having 1 to 18 carbon atoms, an alkenylene group having 1 to 18 carbon atoms, an alkylenedioxy group having 1 to 18 carbon atoms, an arylene group having 6 to 24 carbon atoms, an arylene dioxy group having 6 to 24 carbon atoms, a cycloalkylene group having 3 to 18 carbon atoms, or a cycloalkylenedioxy group having 3 to 18 carbon atoms, which may have a substituent.

2. The phosphorus compound (A) is P(OMe) ３ or P(OEt) ３ The method for producing an aromatic amino compound according to claim 1, 3. The method for producing an aromatic amino compound according to claim 1, wherein the amount of the phosphorus compound (A) used is 5 to 50 mol % based on the aromatic nitro compound.

4. The method for producing an aromatic amino compound according to any one of claims 1 to 3, wherein the aromatic nitro compound is represented by any one of the structures of the following formulas (1) to (3). (In the formula, R ５ , R ６ , R ８ , R ９ each independently represents a single bond or a divalent group; R ７ represents a hydrogen atom or a monovalent group, and n represents an integer of 1 to 2.

5. The method for producing an aromatic amino compound according to any one of claims 1 to 3, wherein the amount of platinum supported in the Pt / C catalyst is 0.5 to 5 wt % based on the total weight of the Pt / C catalyst.

6. The method for producing an aromatic amino compound according to any one of claims 1 to 3, wherein the Pt / C catalyst is an iron-poisoned Pt / C catalyst.

7. The method for producing an aromatic amino compound according to any one of claims 1 to 3, wherein the amount of the Pt / C catalyst used is 1 to 20% by weight based on the aromatic nitro compound.

8. The method for producing an aromatic amino compound according to any one of claims 1 to 3, wherein the reaction temperature in the catalytic reduction is 0 to 100°C and the reaction time is 0.5 to 20 hours.

9. The method for producing an aromatic amino compound according to any one of claims 1 to 3, further comprising the coexistence of a vanadium compound.

10. The vanadium compound is VO(acac) ２ The method for producing an aromatic amino compound according to claim 9, wherein 11. The method for producing an aromatic amino compound according to claim 9, wherein the amount of the vanadium compound used is 0.1 to 1.0 mol % based on the aromatic nitro compound.

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