JP2010241914A - Process for producing azo compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process for producing a compound, which is difficult to synthesize because of unstable diazonium salt, in good yield and in good purity. <P>SOLUTION: A process for producing an azo compound represented by the general formula III (wherein R<SP>1</SP>, R<SP>2</SP>, R<SP>3</SP>, R<SP>4</SP>, and R<SP>5</SP>represent hydrogen or substituents) includes a reaction of a 5-aminopyrazole derivative and a 5-hydroxypyrazole derivative. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing an azo compound.

Diazo compounds are compounds useful as intermediates and products of functional compounds such as photographic additives, sensitizing dyes, dyes, pigments, electronic materials, medical and agrochemicals, and synthetic methods have been known for a long time.
Among them, azo dyes are conventionally widely used as dyes and dyes for image formation in the field of silver halide color photographic light-sensitive materials. On the other hand, in recent years, new color image forming methods such as an ink jet recording method, color electrophotography, thermal transfer method, printing ink, and recording pen have been put into practical use. Further, with the development of electronic imaging, color filters are used for recording and reproducing color images in solid-state imaging tubes and imaging devices such as CCDs, and in displays such as ICDs and PDPs.
In general, these azo dyes are synthesized via a diazo coupling reaction. That is, a desired azo compound can be obtained by reacting an aromatic amine with a diazotizing agent such as sodium nitrite to form a diazonium salt and then subjecting it to a reaction with a coupler (pigment color former).
However, in general, diazonium salts are unstable with aliphatic amines and aromatic amines with high electron-withdrawing properties, and the diazotization reaction causes decomposition, denitrification, and hydrolysis. It is often difficult to obtain stably.
In some cases, a strong acid solvent is used to stabilize the diazonium salt, a system that easily precipitates the diazonium salt from the reaction solution can be designed, and the reaction can be suppressed by a non-aqueous method. Often difficult.
On the other hand, azo compounds can also be synthesized using Mills reaction (Non-Patent Documents 1, 2, 3, 4, 5, 6). That is, the desired active azo compound is obtained by nitrosating the reaction active site of the coupler and dehydrating condensation with an aromatic amine. In general, it is known that this reaction proceeds in a weak acid such as acetic acid.
However, when the diazonium salt is unstable, the raw material aniline often has an electron-withdrawing group in the aromatic ring, and this tends to reduce the nucleophilicity during the Mills reaction at the same time, In the conventional method, the reaction does not proceed at all or only a little is produced.

J. Chem. Soc., Perkin Trans. I, 2001, 1908-1915 J. Org. Chem., 1999, 64, 4976-4979 Tetrahedron lett., 1999, 40, 6557-6560 J. Am. Chem. Soc., 1966, 88, 5015 Bioorg. Med. Chem. Lett., 1994, 4 (17), 2145-2146 Chem. Pharm. Bull., 1983, 31 (4), 1228-1234

  It is an object of the present invention to provide a method for producing a compound that is not easily synthesized due to instability of a thiazonium salt with high yield and high purity.

These conventional problems have been solved by the following means.
(1) An azo compound characterized in that a compound represented by the following general formula (III) is reacted with a compound represented by the following general formula (II) to obtain a compound represented by the following general formula (III) Manufacturing method.

In the formula, R ¹ , R ² , R ³ , R ⁴ , and R ⁵ represent a hydrogen atom or a substituent.
(2) The production method according to (1), wherein the reaction is performed in the presence of a dehydrating agent.
(3) The production method according to (2), wherein sulfuric acid or polyphosphoric acid is used as a dehydrating agent.
(4) The production method according to any one of (1) to (3), wherein at least one of R ¹ and R ³ is a group having an electron-withdrawing group.

According to the method of the present invention, an azo compound can be produced with high yield and high purity.
The object of the present invention relates to a method for producing an azo compound useful as a pharmaceutical intermediate, an image forming material, an optical recording element, an optical film material and the like.

The production method of the present invention will be described.
The production method of the present invention comprises subjecting a compound represented by the following general formula (I) and a compound represented by the general formula (II) to a dehydration condensation reaction to obtain the following general formula (III) Is the method.

（一般式（Ｉ）〜（ＩＩＩ）中Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５は、水素原子または置換基を表す。）

(In the general formulas (I) to (III), R ¹ , R ² , R ³ , R ⁴ and R ⁵ represent a hydrogen atom or a substituent.)

Next, R ^{1 to} R ⁵ in the compounds represented by the general formulas (I) to (III) will be described.
R ^{1 to} R ⁵ each represents a hydrogen atom or a substituent, and may further have a substituent.

  Hereinafter, substituents on the compounds represented by the general formulas (I) to (III) will be described. Examples of the substituent include an alkyl group, a substituted alkyl group, an alkenyl group, a substituted alkenyl group, an alkynyl group, a substituted alkynyl group, an aralkyl group, and a substituted aralkyl group as the aliphatic group. The alkyl group may have a branch or may form a ring. The number of carbon atoms in the alkyl group is preferably 1-20, and more preferably 1-18. The alkyl part of the substituted alkyl group is the same as the above alkyl group. The alkenyl group may have a branch or may form a ring. The alkenyl group has preferably 2 to 20 carbon atoms, and more preferably 2 to 18 carbon atoms. The alkenyl part of the substituted alkenyl group is the same as the above alkenyl group. The alkynyl group may have a branch or may form a ring. The alkynyl group preferably has 2 to 20 carbon atoms, more preferably 2 to 18 carbon atoms. The alkynyl part of the substituted alkynyl group is the same as the above alkynyl group. The alkyl part of the aralkyl group and the substituted aralkyl group is the same as the above alkyl group. The aryl part of the aralkyl group and the substituted aralkyl group is the same as the following aryl group.

  Examples of substituents in the alkyl part of the substituted alkyl group, substituted alkenyl group, substituted alkynyl group and substituted aralkyl group include a halogen atom (for example, chlorine atom, bromine atom, iodine atom), alkyl group [straight chain, branched, cyclic Represents a substituted or unsubstituted alkyl group. They are alkyl groups (preferably alkyl groups having 1 to 30 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, t-butyl, n-octyl, eicosyl, 2-chloroethyl, 2-cyanoethyl, 2-ethylhexyl). A cycloalkyl group (preferably a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, such as cyclohexyl, cyclopentyl, 4-n-dodecylcyclohexyl), a bicycloalkyl group (preferably having 5 to 30 carbon atoms). A substituted or unsubstituted bicycloalkyl group, that is, a monovalent group obtained by removing one hydrogen atom from a bicycloalkane having 5 to 30 carbon atoms, for example, bicyclo [1,2,2] heptan-2-yl, bicyclo [2,2,2] octane-3-yl), a tricyclo structure with more ring structures Domo is intended to cover. An alkyl group (for example, an alkyl group of an alkylthio group) in the substituents described below also represents such an alkyl group. ], An alkenyl group [represents a linear, branched or cyclic substituted or unsubstituted alkenyl group. They are alkenyl groups (preferably substituted or unsubstituted alkenyl groups having 2 to 30 carbon atoms, such as vinyl, allyl, prenyl, geranyl, oleyl), cycloalkenyl groups (preferably substituted or substituted groups having 3 to 30 carbon atoms). An unsubstituted cycloalkenyl group, that is, a monovalent group obtained by removing one hydrogen atom of a cycloalkene having 3 to 30 carbon atoms (for example, 2-cyclopenten-1-yl, 2-cyclohexen-1-yl), Bicycloalkenyl group (a substituted or unsubstituted bicycloalkenyl group, preferably a substituted or unsubstituted bicycloalkenyl group having 5 to 30 carbon atoms, that is, a monovalent group obtained by removing one hydrogen atom of a bicycloalkene having one double bond. For example, bicyclo [2,2,1] hept-2-en-1-yl, bicyclo 2,2,2] oct-2-en-4-yl). ], An alkynyl group (preferably a substituted or unsubstituted alkynyl group having 2 to 30 carbon atoms, such as ethynyl, propargyl, trimethylsilylethynyl group, aryl group (preferably a substituted or unsubstituted aryl group having 6 to 30 carbon atoms) For example, phenyl, p-tolyl, naphthyl, m-chlorophenyl, o-hexadecanoylaminophenyl), a heterocyclic group (preferably a 5- or 6-membered substituted or unsubstituted aromatic or non-aromatic heterocyclic compound A monovalent group in which one hydrogen atom is removed from, and more preferably a 5- or 6-membered aromatic heterocyclic group having 3 to 30 carbon atoms, such as 2-furyl, 2-thienyl, 2 -Pyrimidinyl, 2-benzothiazolyl), cyano group, hydroxyl group, nitro group, carboxyl group, alkoxy group Preferably, it is a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, such as methoxy, ethoxy, isopropoxy, t-butoxy, n-octyloxy, 2-methoxyethoxy), aryloxy group (preferably having a carbon number) 6 to 30 substituted or unsubstituted aryloxy groups such as phenoxy, 2-methylphenoxy, 4-t-butylphenoxy, 3-nitrophenoxy, 2-tetradecanoylaminophenoxy), silyloxy groups (preferably carbon 3 to 20 silyloxy groups such as trimethylsilyloxy, t-butyldimethylsilyloxy), heterocyclic oxy groups (preferably substituted or unsubstituted heterocyclic oxy groups having 2 to 30 carbon atoms, 1-phenyltetrazole 5-oxy, 2-tetrahydropyranyloxy An acyloxy group (preferably a formyloxy group, a substituted or unsubstituted alkylcarbonyloxy group having 2 to 30 carbon atoms, a substituted or unsubstituted arylcarbonyloxy group having 6 to 30 carbon atoms, such as formyloxy, acetyloxy, Pivaloyloxy, stearoyloxy, benzoyloxy, p-methoxyphenylcarbonyloxy), a carbamoyloxy group (preferably a substituted or unsubstituted carbamoyloxy group having 1 to 30 carbon atoms, such as N, N-dimethylcarbamoyloxy, N, N-diethylcarbamoyloxy, morpholinocarbonyloxy, N, N-di-n-octylaminocarbonyloxy, Nn-octylcarbamoyloxy), alkoxycarbonyloxy group (preferably having 2 to 30 carbon atoms) Or an unsubstituted alkoxycarbonyloxy group, for example, methoxycarbonyloxy, ethoxycarbonyloxy, t-butoxycarbonyloxy, n-octylcarbonyloxy), an aryloxycarbonyloxy group (preferably a substituted or unsubstituted group having 7 to 30 carbon atoms) Aryloxycarbonyloxy group of, for example, phenoxycarbonyloxy, p-methoxyphenoxycarbonyloxy, pn-hexadecyloxyphenoxycarbonyloxy), amino group (preferably amino group, substituted or unsubstituted having 1 to 30 carbon atoms) Alkylamino groups, substituted or unsubstituted anilino groups having 6 to 30 carbon atoms, such as amino, methylamino, dimethylamino, anilino, N-methyl-anilino, diphenylamino), acylamino groups (preferably Is a formylamino group, a substituted or unsubstituted alkylcarbonylamino group having 1 to 30 carbon atoms, a substituted or unsubstituted arylcarbonylamino group having 6 to 30 carbon atoms, such as formylamino, acetylamino, pivaloylamino, lauroylamino , Benzoylamino, 3,4,5-tri-n-octyloxyphenylcarbonylamino), an aminocarbonylamino group (preferably a substituted or unsubstituted aminocarbonylamino having 1 to 30 carbon atoms such as carbamoylamino, N , N-dimethylaminocarbonylamino, N, N-diethylaminocarbonylamino, morpholinocarbonylamino), an alkoxycarbonylamino group (preferably a substituted or unsubstituted alkoxycarbonylamino group having 2 to 30 carbon atoms, for example, Toxicarbonylamino, ethoxycarbonylamino, t-butoxycarbonylamino, n-octadecyloxycarbonylamino, N-methyl-methoxycarbonylamino), aryloxycarbonylamino group (preferably substituted or unsubstituted having 7 to 30 carbon atoms) Aryloxycarbonylamino group, for example, phenoxycarbonylamino, p-chlorophenoxycarbonylamino, mn-octyloxyphenoxycarbonylamino), sulfamoylamino group (preferably substituted or unsubstituted having 0 to 30 carbon atoms) Sulfamoylamino groups such as sulfamoylamino, N, N-dimethylaminosulfonylamino, Nn-octylaminosulfonylamino), alkyl and arylsulfonylamino groups (preferably having 1 carbon atom) To 30 substituted or unsubstituted alkylsulfonylamino, substituted or unsubstituted arylsulfonylamino having 6 to 30 carbon atoms, such as methylsulfonylamino, butylsulfonylamino, phenylsulfonylamino, 2,3,5-trichlorophenylsulfonyl Amino, p-methylphenylsulfonylamino), mercapto group, alkylthio group (preferably a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, such as methylthio, ethylthio, n-hexadecylthio), arylthio group (preferably carbon number) 6-30 substituted or unsubstituted arylthio, for example, phenylthio, p-chlorophenylthio, m-methoxyphenylthio), a heterocyclic thio group (preferably a substituted or unsubstituted heterocyclic thio group having 2 to 30 carbon atoms) For example, 2-benzothiazolylthio, 1-phenyltetrazol-5-ylthio), a sulfamoyl group (preferably a substituted or unsubstituted sulfamoyl group having 0 to 30 carbon atoms such as N-ethylsulfamoyl, N- ( 3-dodecyloxypropyl) sulfamoyl, N, N-dimethylsulfamoyl, N-acetylsulfamoyl, N-benzoylsulfamoyl, N- (N′-phenylcarbamoyl) sulfamoyl), sulfo group, alkyl and arylsulfinyl A group (preferably a substituted or unsubstituted alkylsulfinyl group having 1 to 30 carbon atoms, a substituted or unsubstituted arylsulfinyl group having 6 to 30 carbon atoms, such as methylsulfinyl, ethylsulfinyl, phenylsulfinyl, p-methylphenylsulfinyl) A Kills and arylsulfonyl groups (preferably substituted or unsubstituted alkylsulfonyl groups having 1 to 30 carbon atoms, substituted or unsubstituted arylsulfonyl groups having 6 to 30 carbon atoms such as methylsulfonyl, ethylsulfonyl, phenylsulfonyl, p- Methylphenylsulfonyl), acyl group (preferably formyl group, substituted or unsubstituted alkylcarbonyl group having 2 to 30 carbon atoms, substituted or unsubstituted arylcarbonyl group having 7 to 30 carbon atoms, substitution having 4 to 30 carbon atoms) Or a heterocyclic carbonyl group bonded to a carbonyl group with an unsubstituted carbon atom, such as acetyl, pivaloyl, 2-chloroacetyl, stearoyl, benzoyl, pn-octyloxyphenylcarbonyl, 2-pyridylcarbonyl, 2- Furylcarbonyl), ally A ruoxycarbonyl group (preferably a substituted or unsubstituted aryloxycarbonyl group having 7 to 30 carbon atoms such as phenoxycarbonyl, o-chlorophenoxycarbonyl, m-nitrophenoxycarbonyl, pt-butylphenoxycarbonyl), An alkoxycarbonyl group (preferably a substituted or unsubstituted alkoxycarbonyl group having 2 to 30 carbon atoms such as methoxycarbonyl, ethoxycarbonyl, t-butoxycarbonyl, n-octadecyloxycarbonyl), a carbamoyl group (preferably having 1 to 1 carbon atoms) 30 substituted or unsubstituted carbamoyl such as carbamoyl, N-methylcarbamoyl, N, N-dimethylcarbamoyl, N, N-di-n-octylcarbamoyl, N- (methylsulfonyl) carbamoyl) Aryl and heterocyclic azo groups (preferably substituted or unsubstituted arylazo groups having 6 to 30 carbon atoms, substituted or unsubstituted heterocyclic azo groups having 3 to 30 carbon atoms such as phenylazo, p-chlorophenylazo, 5- Ethylthio-1,3,4-thiadiazol-2-ylazo), an imide group (preferably N-succinimide, N-phthalimide), a phosphino group (preferably a substituted or unsubstituted phosphino group having 2 to 30 carbon atoms, For example, dimethylphosphino, diphenylphosphino, methylphenoxyphosphino), phosphinyl group (preferably a substituted or unsubstituted phosphinyl group having 2 to 30 carbon atoms, such as phosphinyl, dioctyloxyphosphinyl, diethoxyphosphini ), A phosphinyloxy group (preferably A substituted or unsubstituted phosphinyloxy group having 2 to 30 carbon atoms, such as diphenoxyphosphinyloxy, dioctyloxyphosphinyloxy), a phosphinylamino group (preferably a substitution having 2 to 30 carbon atoms) Or an unsubstituted phosphinylamino group such as dimethoxyphosphinylamino or dimethylaminophosphinylamino), a silyl group (preferably a substituted or unsubstituted silyl group having 3 to 30 carbon atoms such as trimethylsilyl, t-butyldimethylsilyl, phenyldimethylsilyl).

  Among the above functional groups, those having a hydrogen atom may be substituted with the above groups by removing this. Examples of such functional groups include an alkylcarbonylaminosulfonyl group, an arylcarbonylaminosulfonyl group, an alkylsulfonylaminocarbonyl group, and an arylsulfonylaminocarbonyl group. Examples thereof include methylsulfonylaminocarbonyl, p-methylphenylsulfonylaminocarbonyl, acetylaminosulfonyl, and benzoylaminosulfonyl groups.

  The example of the substituent of the aryl part of a substituted aralkyl group is the same as the example of the substituent of the following substituted aryl group.

  Moreover, when it has an aromatic group as a substituent, an aryl group and a substituted aryl group are mentioned as an aromatic group. These aromatic groups may be condensed with an aliphatic ring, another aromatic ring or a heterocyclic ring. The number of carbon atoms in the aromatic group is preferably 6 to 40, more preferably 6 to 30, and still more preferably 6 to 20. Among them, the aryl group is preferably phenyl or naphthyl, particularly preferably phenyl.

  The aryl part of the substituted aryl group is the same as the above aryl group. Examples of the substituent of the substituted aryl group are the same as those described above as examples of the substituent of the alkyl portion of the substituted alkyl group, the substituted alkenyl group, the substituted alkynyl group, and the substituted aralkyl group.

The electron-withdrawing group in the present invention is a substituent having an electron-withdrawing property due to an electronic effect, and Hammett's substituent constant σp value, which is a measure of the electron-withdrawing property and electron-donating property of the substituent, is If used, it is a substituent having a large σp value. Examples thereof include a cyano group, a nitro group, a halogen atom, a sulfo group, a trifluoromethyl group, an alkoxycarbonyl group, and an acyl group.
Hammett's substituent constant σp value will be described briefly. Hammett's rule is an empirical rule proposed by LP Hammett in 1935 to quantitatively discuss the influence of substituents on the reaction or equilibrium of benzene derivatives, but this is widely accepted today. Substituent constants determined by Hammett's rule include σp value and σm value, and these values can be found in many general books. For example, JADean edition “Lange's Handbook of Chemistry” 12th edition 1979 (Mc Graw-Hill), “Chemical Fields”, Extra 122, 96-103, 1979 (Nankodo).

Examples of preferable substituents in the compounds represented by the general formulas (I), (II), and (III) will be described below.
R ¹ , R ² , R ³ , R ⁴ , R ⁵ are preferably hydrogen atom, halogen atom, alkyl group, alkenyl group, alkynyl group, aryl group, cyano group, hydroxyl group, carboxyl group, alkoxy group, aryloxy group Silyloxy group, acyloxy group, carbamoyloxy group, alkoxycarbonyloxy group, aryloxycarbonyloxy group, amino group, acylamino group, aminocarbonylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfamoylamino group, Alkyl and arylsulfonylamino groups, mercapto groups, alkylthio groups, arylthio groups, sulfamoyl groups, sulfo groups, alkyl and arylsulfinyl groups, alkyl and arylsulfonyl groups, acyl groups, aryl groups Sicarbonyl group, alkoxycarbonyl group, carbamoyl group, imide group, phosphino group, phosphinyl group, phosphinyloxy group, phosphinylamino group, silyl group, more preferably hydrogen atom, alkyl group, alkenyl group, aryl Group, cyano group, hydroxyl group, carboxyl group, alkoxy group, amino group, alkylthio group, arylthio group, imide group, silyl group, more preferably hydrogen atom, alkyl group, aryl group, alkoxy group, aryloxy group, A silyloxy group and an amino group, most preferably a hydrogen atom, an alkyl group or an aryl group. The number of carbon atoms in these groups or atoms is as described above.

In the present invention, at least one of R ¹ and R ³ is preferably a group having an electron-withdrawing group, and R ³ is more preferably an electron-withdrawing group.
The electron-withdrawing group is preferably an electron-withdrawing group having a Hammett's substituent constant σp value of 0.20 or more, and more preferably an electron-withdrawing group having a σp value of 0.30 or more. . The upper limit of the σp value is not particularly limited, but is usually 0.85 or less.
Specific examples of R ² which is an electron withdrawing group having a σp value of 0.20 or more include acyl group, acyloxy group, carbamoyl group, alkyloxycarbonyl group, aryloxycarbonyl group, cyano group, nitro group, dialkylphosphonic group Group, diarylphosphono group, diarylphosphinyl group, alkylsulfinyl group, arylsulfinyl group, alkylsulfonyl group, arylsulfonyl group, sulfonyloxy group, acylthio group, sulfamoyl group, thiocyanate group, thiocarbonyl group, alkyl halide Groups, halogenated alkoxy groups, halogenated aryloxy groups, halogenated alkylamino groups, halogenated alkylthio groups, aryl groups substituted with other electron-withdrawing groups having a σp value of 0.20 or more, heterocyclic groups, Halogen atom, azo group, or selenoshi Include sulfonate groups.
R ¹³ is a nitro group, a cyano group, or —CO—R ⁶ , and R ⁶ represents a hydrogen atom, an aliphatic group, an aromatic group, an alkoxy group, or an amino group. Particularly preferred are a cyano group and a nitro group.

Preferred combinations of substituents as R ¹ , R ² , R ³ , R ⁴ and R ⁵ in the compound represented by the general formula (III) are listed below.

  The compound represented by the general formula (I) and the compound represented by the general formula (II) of the present invention are commercially available, and can be easily synthesized according to a conventional method.

In the present invention, the compounds represented by the general formulas (I) to (III) may contain isotopes (eg, ² H, ³ H, ¹³ C, ¹⁵ N) in the structure. Good.

  The compounds used in the present invention include those accompanied with a counter salt by the synthesis process or isolation method. Any salt may be used, and examples thereof include halide ions, sulfate ions, nitrate ions, carbonate ions, sulfonate ions, phosphate ions, acetate ions, metal ions, and ammonium ions. Depending on the structure, an inner salt may be formed.

  In the production method of the present invention, the reaction temperature for reacting the compound represented by the general formula (I) with the compound represented by the general formula (II) is preferably −30 to 200 ° C., more preferably 20 to 150 ° C., most preferably 60 to 120 ° C.

  The amount of the compound represented by the general formula (II) relative to the amount of the compound represented by the general formula (I) contained in the reaction mixture is 1.0 to 6.0 mol, more preferably 1.0 to 5 mol. 0.0 mol and most preferably in the range of 1.0 to 4.0 mol.

  In carrying out the reaction, the order of adding the compound represented by the general formula (I) and the compound represented by the general formula (II) into the reaction system is arbitrary, and is not particularly limited.

  In the present invention, it is preferable to use a solvent for the reaction. Examples of the solvent include water, amide solvents (for example, N, N-dimethylformamide, N, N-dimethylacetamide, 1-methyl-2-pyrrolidone), sulfone solvents (for example, sulfolane), sulfoxide solvents (for example, dimethyl sulfoxide), Ureide solvents (eg tetramethylurea), ether solvents (eg dioxane, cyclopentylmethyl ether), ketone solvents (eg acetone, cyclohexanone), hydrocarbon solvents (eg toluene, xylene, n-decane), halogen solvents (Eg, tetrachloroethane, chlorobenzene), alcohol solvents (eg, methanol, ethanol, isopropyl alcohol, ethylene glycol, cyclohexanol, phenol), pyridine solvents (eg, pyridine, γ-picoline, , 6-lutidine), ester solvents (e.g. ethyl acetate, butyl acetate), carboxylic acid solvents (e.g. acetic acid, propionic acid) and nitrile-based solvents (e.g., acetonitrile) is used alone or in combination. Among these, water, a sulfone solvent, an ether solvent, a ketone solvent, and a halogen solvent are preferable, and water and a sulfone solvent are most preferable.

  In the present invention, the amount of the solvent with respect to the compound represented by the general formula (I) is 100 times or less, more preferably 50 times or less, and further preferably 10 times or less by mass ratio. Further, when the solvent and acid are used, the solvent may not be used.

In the method of the present invention, an inorganic acid (also called a mineral acid) and an organic acid can be used as the acid present during the reaction. For example, acetic acid, propionic acid, methanesulfonic acid, and p-toluenesulfonic acid can be preferably used as the organic acid. As the inorganic acid, for example, hydrochloric acid, sulfuric acid, phosphoric acid and the like can be preferably used. As the acid, only one kind of the above-mentioned acids may be used, or two or more kinds may be used in combination.
The amount of the acid used is 100% or more, preferably 100 to 1000% by weight with respect to the compound represented by formula (I).

Examples of the dehydrating agent include concentrated sulfuric acid (98% or more), polyphosphoric acid, metaphosphoric acid, pyrophosphoric acid, phosphoric anhydride, diphosphorus pentoxide, molecular sieves (3A), molecular sieves (4A), anhydrous magnesium sulfate, Examples include anhydrous sodium sulfate, organic carboxylic acid anhydrides, N, N-dialkylcarbodiimides, lower fatty acid halides, halogenated lower fatty acid halides, halogenated lower fatty acid anhydrides, arylphosphonic acid dihalides and thionyl halides. Preferred are concentrated sulfuric acid, polyphosphoric acid, metaphosphoric acid, and anhydrous phosphoric acid.
In this invention, the usage-amount of a dehydrating agent is 300 mass% or more by weight ratio with respect to the compound represented with general formula (I), and 300-1000 mass% is preferable. If the amount of the dehydrating agent is too large, a decomposition reaction may be observed. If the amount is too small, the reaction rate becomes slow or the reaction does not proceed. When the same acid as the dehydrating agent is used, the amount of the acid is reduced for reaction.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited thereto.

  Amino compounds and nitroso compounds can be easily synthesized by known synthesis methods.

Example 1 Synthesis of Compound Example (3) 5 g of 5-amino-4-methoxycarbonyl-3-methylpyrazole and 4.1 g of 5-hydroxy-3-methyl-4-nitrosopyrazole were dissolved in 20 ml of concentrated sulfuric acid, and the mixture was dissolved at 80 ° C. And stirred for 5 hours. Thereafter, the reaction solution was dropped into 300 ml of ice water, and the precipitated crystals were filtered. The obtained crystals were washed with water and dried to obtain 5.0 g (59%) of the desired compound (3).
When the mass spectrum of this product was measured, it was M ⁺ = 264.

Example 2 Synthesis of Compound Example (5) 5 g of 5-amino-4-methyl-3-methylpyrazole and 5.2 g of 5-hydroxy-3-methyl-4-nitrosopyrazole were dissolved in 20 ml of concentrated sulfuric acid at 80 ° C. The mixture was heated and stirred for 5 hours. Thereafter, the reaction solution was dropped into 300 ml of ice water, and the precipitated crystals were filtered. The obtained crystals were washed with water and dried to obtain 5.3 g (56%) of the desired compound (5).
When the mass spectrum of this product was measured, it was M ⁺ = 231.

Example 3 Synthesis of Compound Example (7) In 20 ml of concentrated sulfuric acid, 5 g of 5-amino-3-tert-butyl-4-methoxycarbonylpyrazole and 5.2 g of 5-hydroxy-3-methyl-4-nitroso-1-phenylpyrazole were added. It melt | dissolved and it heat-stirred at 80 degreeC for 5 hours. Thereafter, the reaction solution was dropped into 300 ml of ice water, and the precipitated crystals were filtered. The obtained crystals were washed with water and dried to obtain 5.1 g (53%) of the desired compound (7).
When a mass spectrum of this product was measured, it was M ⁺ = 382.

Example 4 Synthesis of Compound Example (8) Dissolve 5 g of 5-amino-3-tert-butyl-4-cyanopyrazole and 6.2 g of 5-hydroxy-3-methyl-4-nitroso-1-phenylpyrazole in 20 ml of concentrated sulfuric acid. And stirred at 80 ° C. for 5 hours. Thereafter, the reaction solution was dropped into 300 ml of ice water, and the precipitated crystals were filtered. The obtained crystals were washed with water and dried to obtain 6.5 g (61%) of the desired compound (8).
When a mass spectrum of this product was measured, it was M ⁺ = 349.

(Example 5) Synthesis of Compound Example (10) 5 g of 5-amino-4-cyano-3-phenylpyrazole and 5.0 g of 3-t-butyl-5-hydroxy-1-methyl-4-nitrosopyrazole were dissolved in 20 ml of concentrated sulfuric acid. And stirred at 80 ° C. for 5 hours. Thereafter, the reaction solution was dropped into 300 ml of ice water, and the precipitated crystals were filtered. The obtained crystals were washed with water and dried to obtain 5.2 g (55%) of the desired compound (10).
When a mass spectrum of this product was measured, it was M ⁺ = 349.

Example 6 Synthesis of Compound Example (13) 5-Amino-4-methoxycarbonyl-1,5-dimethylpyrazole 5 g, 5-hydroxy-3-methyl-4-nitrosopyrazole 3.8 g were dissolved in 20 ml of concentrated sulfuric acid. The mixture was heated and stirred at 80 ° C. for 5 hours. Thereafter, the reaction solution was dropped into 300 ml of ice water, and the precipitated crystals were filtered. The obtained crystals were washed with water and dried to obtain 4.3 g (52%) of the desired compound (13).
When the mass spectrum of this product was measured, it was M ⁺ = 278.

Example 7 Synthesis of Compound Example (15) 5 g of 5-amino-4-cyano-1,3-dimethylpyrazole and 4.7 g of 5-hydroxy-3-methyl-4-nitrosopyrazole were dissolved in 20 ml of concentrated sulfuric acid at 80 ° C. And stirred for 5 hours. Thereafter, the reaction solution was dropped into 300 ml of ice water, and the precipitated crystals were filtered. The obtained crystals were washed with water and dried to obtain 5.0 g (55%) of the desired compound (15).
When the mass spectrum of this product was measured, it was M ⁺ = 245.

(Example 8) Synthesis of Compound Example (18) 5 g of 5-amino-3-tert-butyl-4-cyano-1-methylpyrazole, 5-hydroxy-3-methyl-4-nitroso-1-phenylpyrazole in 20 ml of concentrated sulfuric acid 7 g was dissolved and stirred with heating at 80 ° C. for 5 hours. Thereafter, the reaction solution was dropped into 300 ml of ice water, and the precipitated crystals were filtered. The obtained crystals were washed with water and dried to obtain 6.2 g (56%) of the desired compound (18).
When the mass spectrum of this product was measured, it was M ⁺ = 396.

Example 9 Synthesis of Compound Example (20) 5-Amino-4-cyano-1-methyl-3-phenylpyrazole (5 g) and 3-t-butyl-5-hydroxy-1-methyl-4-nitrosopyrazole (4.6 g) in 20 ml of concentrated sulfuric acid Was dissolved and heated and stirred at 80 ° C. for 5 hours. Thereafter, the reaction solution was dropped into 300 ml of ice water, and the precipitated crystals were filtered. The obtained crystals were washed with water and dried to obtain 5.8 g (63%) of the desired compound (20).
When a mass spectrum of this product was measured, it was M ⁺ = 363.

Example 10 Synthesis of Compound Example (25) 5 g of 5-amino-4-cyano-3-methyl-1-phenylpyrazole and 3.2 g of 5-hydroxy-3-methyl-4-nitrosopyrazole were dissolved in 20 ml of concentrated sulfuric acid. The mixture was stirred at 5 ° C. for 5 hours. Thereafter, the reaction solution was dropped into 300 ml of ice water, and the precipitated crystals were filtered. The obtained crystals were washed with water and dried to obtain 4.8 g (62%) of the desired compound (25).
When the mass spectrum of this product was measured, it was M ⁺ = 307.

(Example 11) Synthesis of Compound Example (28) 5 g of 5-amino-3-tert-butyl-4-cyano-1-phenylpyrazole, 5-hydroxy-3-methyl-4-nitroso-1-phenylpyrazole in 20 ml of concentrated sulfuric acid 2g was melt | dissolved and it heat-stirred at 80 degreeC for 5 hours. Thereafter, the reaction solution was dropped into 300 ml of ice water, and the precipitated crystals were filtered. The obtained crystals were washed with water and dried to obtain 5.4 g (57%) of the desired compound (28).
When a mass spectrum of this product was measured, it was M ⁺ = 459.

(Example 12) Synthesis of Compound Example (30) In 20 ml of concentrated sulfuric acid, 5 g of 5-amino-4-cyano-1,3-diphenylpyrazole and 3.5 g of 3-t-butyl-5-hydroxy-1-methyl-4-nitrosopyrazole were added. It melt | dissolved and it heat-stirred at 80 degreeC for 5 hours. Thereafter, the reaction solution was dropped into 300 ml of ice water, and the precipitated crystals were filtered. The obtained crystals were washed with water and dried to obtain 4.7 g (57%) of the desired compound (30).
When the mass spectrum of this product was measured, it was M ⁺ = 426.

Comparative example

Synthesis of Compound (30) 5 g of 5-amino-4-cyano-1,3-diphenylpyrazole and 3.5 g of 3-t-butyl-5-hydroxy-1-methyl-4-nitrosopyrazole were dissolved in 20 ml of acetic acid and dissolved at 80 ° C. Stir for hours. Although measured by HPLC, compound (30) was not produced at all.
Therefore, the temperature was further raised and the mixture was stirred for 5 hours under reflux with heating, but no product was confirmed.

Claims (4)

A process for producing an azo compound, comprising: reacting a compound represented by the following general formula (I) with a compound represented by the general formula (II) to obtain a compound represented by the following general formula (III): .

In the formula, R ¹ , R ² , R ³ , R ⁴ , and R ⁵ represent a hydrogen atom or a substituent.   The process according to claim 1, wherein the reaction is carried out in the presence of a dehydrating agent.   The production method according to claim 2, wherein sulfuric acid or polyphosphoric acid is used as a dehydrating agent. The production method according to claim 1, wherein at least one of R ¹ and R ³ is a group having an electron-withdrawing group.