JP2879837B2 - Method for producing azo compound - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an azo compound which is useful as a substance used as a functional material or a dye.

[0002]

2. Description of the Related Art In recent years, organic dyes have attracted attention as functional materials, and such organic materials have various merits, such as less toxicity than inorganic materials, easy thinning, and low cost. In order for an organic dye to be used as a functional material, special functions required for various uses are required in addition to stability and durability as a material. However, at present, it is hard to say that the functionality, stability, durability, etc. are sufficient compared to inorganic materials except for a part.

On the other hand, in order to use an organic dye as a material, cost and purity become important issues in addition to the above-mentioned functions and the like, and an efficient method for producing a material is required. For example, a diazonium ion is an electrophile and reacts with various nucleophiles, and as a nucleophile containing nitrogen, for example, an aromatic tertiary amine, an azo compound by a coupling reaction, and an aromatic primary and secondary It is already known that it reacts with an amine at the N-position to form a diazoamino compound. However, in this reaction, depending on the type of the substituent on the aromatic ring, in addition to the diazoamino compound reacted at the N-position, an azo compound reacted with the aromatic ring is simultaneously produced as a by-product, resulting in poor efficiency.

[0004]

An object of the present invention is to provide a method for producing an azo compound using a novel azo compound used for a functional material or a dye.

[0005]

Means for Solving the Problems The present invention provides the following general formula (1)

[0006]

Embedded image (Wherein, Ar represents an aryl group which may have a substituent. R ₁ represents a hydrogen atom, an alkyl group, or an aryl group which may have a substituent. R ₂ represents an alkyl group or a substituent. R ₃ represents an alkyl group, an aryl group optionally having a substituent, or a hydroxyl group, and X ⁻ represents a counter anion.) The following general formula (2) characterized by hydrolysis: Ar—N ＝ N—NH—R ₃ (2) (wherein, Ar represents an aryl group which may have a substituent. R ₃ is alkyl Or an aryl group which may have a substituent or a hydroxyl group.).

In the general formula (1), Ar represents an aryl group which may have a substituent. Examples of the aryl group include a phenyl group, a naphthyl group and an anthranyl group. Alkyl groups such as groups, halogen atoms such as fluorine atoms, chlorine atoms and bromine atoms, alkoxy groups such as nitro groups and methoxy groups, amino groups such as dimethylamino groups, and hydroxyl groups. R ₁
Represents a hydrogen atom, an alkyl group such as a methyl group, an ethyl group or a cyclohexyl group, or an aryl group which may have a substituent, and the aryl group and the substituent are the same as described above. R ₂ represents an alkyl group such as a methyl group, an ethyl group or a cyclohexyl group or an aryl group which may have a substituent, and the aryl group and the substituent are the same as described above. R
Reference numeral ₃ denotes an alkyl group such as a methyl group, an ethyl group or a cyclohexyl group, an aryl group which may have a substituent, or a hydroxyl group, wherein the aryl group and the substituent are the same as described above. Further, X ^- represents a counter anion, Cl ^-, SO ₄ ^-
And anions of mineral acids such as BF ₄ ⁻ and PF ₆ ⁻ .

The compound of the general formula (1) is prepared from a diazonium salt and an imine (reaction formula 1).

[0009]

Embedded image In Scheme 1, Ar and X of the diazonium salt ^- the general formula (1) of Ar and X ^- are the same as, imine R
_1, R _2, R ₃ is the same as R _1, R _2, R ₃ in the general formula (1). In preparing the compound of the general formula (1), 0.5 to 2 parts by weight of imine is added to 1 part by weight of the diazonium salt,
Preferably, 0.8 to 1.2 parts by weight are used, and as the solvent, an organic solvent from which water has been removed such as acetonitrile, dimethylformamide, dichloromethane, ethyl acetate and nitromethane is used. The amount of water contained in the organic solvent is preferably 1% by weight or less, more preferably 0.1% by weight.
Not more than 1% by weight. The reaction temperature is preferably -1.
It is in the range of 0 to 30 ° C, more preferably in the range of 0 to 10 ° C.

The diazonium salt used in the method for preparing the compound of the general formula (1) is obtained by diazotizing the corresponding amine by a conventional method, and then purifying and isolating it with hydrogen borofluoride or the like. Imine is described in the literature (A. Hantzsch, Ch.
em. Ber. 34 , 822, 1901 et al.) From the corresponding amine and aldehyde.

The compound of the formula (1) itself has a function as a dye, and is also useful as an intermediate in various subsequent reactions.

In the present invention, the compound of the general formula (2) is produced from the hydrolysis of the compound of the general formula (1).
In the production of the compound of the general formula (2) according to the present invention, the compound of the general formula (1) may be isolated and then hydrolyzed,
Alternatively, hydrolysis may be performed without isolation, as a solution containing the compound of the general formula (1). The hydrolysis method is represented by the general formula (1)
May be added to water and stirred with water, or the organic solvent may be added with water and stirred. Examples of the organic solvent include acetonitrile, dimethylformamide, ethyl acetate and the like. Further, the compound of the general formula (1) may be directly dissolved in water and stirred. The reaction temperature is preferably in the range of -10 to 30C, more preferably in the range of 0 to 10C.

The general formulas (1) and (2) according to the present invention are described below.
Tables 1 and 2 show typical structures of the above.

[0014]

Embedded image

[0015]

[Table 1] Ar-N = N-NH- R 3 (2)

[0016]

[Table 2]

[0017]

The present invention will be described below with reference to examples.

Synthesis Example 1 (Production of Compound No. 1) 1.37 g of 4-nitrobenzenediazonium tetrafluoroborate and 1.50 g of 4-bromo-N-benzylideneaniline
g in 50 ml of dry acetonitrile and 5
Stirred at about 1 hour. After the reaction, the deposited precipitate was filtered to obtain 0.52 g of orange crystals. Yield: 18%. The melting point of the obtained crystal was measured, and mass analysis was performed. Melting point: 120
~ 124 ° C, MS (m / e): 450 (M ⁺ -NO ₂ )

Synthesis Example 2 (Production of Compound No. 2) 1.11 g of 4-nitrobenzenediazonium tetrafluoroborate and 1.20 g of N-diphenylideneaniline were mixed with 60
dissolved in 5 ml of dry acetonitrile and
Stirred for hours. After the reaction, the deposited precipitate was filtered to obtain 0.48 g of a black-brown crude crystal. This was further washed with acetonitrile, and after filtration, 0.1 g of crystals was obtained. Yield: 4%, melting point: 199-202 ° C, MS (m / e): 493 (M
⁺ )

Example 1 (Production of Compound No. 6) 1.37 g of 4-nitrobenzenediazonium tetrafluoroborate and 1.50 g of 4-bromo-N-benzylideneaniline
g in 30 ml of dimethylformamide.
For about 15 minutes. After the reaction, the solution was added to 100 ml of ice water, and the resulting precipitate was filtered.
g was obtained. Yield: 89%, melting point: 173-174 ° C. It was confirmed that the obtained compound was the same as the obtained compound by mixing and melting with a separately synthesized sample.

[0021]

As described above, according to the present invention, a method for efficiently producing an azo compound using a novel azo compound can be provided.

Claims (1)

(57) [Claims] [Claim 1] The following general formula (1) (Wherein, Ar represents an aryl group which may have a substituent. R ₁ represents a hydrogen atom, an alkyl group, or an aryl group which may have a substituent. R ₂ represents an alkyl group or a substituent. R ₃ represents an alkyl group, an aryl group optionally having a substituent, or a hydroxyl group, and X ⁻ represents a counter anion.) The following general formula (2) characterized by hydrolysis: Ar—N ＝ N—NH—R ₃ (2) (wherein, Ar represents an aryl group which may have a substituent. R ₃ is alkyl A hydroxyl group, an aryl group which may have a substituent or a hydroxyl group.).