JP2986467B2 - Method for producing azo compound - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing an azo compound 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. Also, in the synthesis of the azo compound of the general formula (3), the selectivity also deteriorates depending on the type of the substituent.

[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 (3):

[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 ₄ represents an aryl group which may have a substituent; X ⁻ represents a counter anion; and the azo compound represented by the formula (I) is subjected to a rearrangement reaction. The following general formula (4)

[0007]

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. And R ₅ represents an arylene group having one bonding group from R ₄ ).

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a compound of the general formula (4) is produced from a compound of the general formula (3) which is a subordinate concept of the compound of the following general formula (1). First, the compound of the general formula (1) and a method for preparing the same will be described. General formula (1)

[0009]

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.) In the general formula (1), Ar represents an aryl group which may have a substituent, wherein the aryl group includes a phenyl group, a naphthyl group, an anthranyl group and the like; and the substituents include an alkyl group such as a methyl group and an ethyl group; a fluorine atom; Examples include an atom, a halogen atom such as a bromine atom, an alkoxy group such as a nitro group and a methoxy group, an amino group such as a dimethylamino group, and a hydroxyl group. R ₁ is a hydrogen atom,
It represents an alkyl group such as a methyl group, an ethyl group, a cyclohexyl group, or an aryl group which may have a substituent. 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 ₃ is a methyl group,
An alkyl group such as an ethyl group and 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. X ⁻ represents a counter anion, such as a mineral acid anion such as Cl ⁻ and SO ₄ ^— or an anion 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).

[0011]

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) was prepared by diazotizing the corresponding amine by a conventional method, and then purified and isolated 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 general formula (1) itself has a function as a dye, and is also useful as an intermediate in various subsequent reactions.

Next, a method for producing the compound of the general formula (4) from the compound of the general formula (3), the compound of the general formula (4) and the compound of the general formula (3) of the present invention will be described. In the general formula (3), Ar, R ₁ and R ₂ are the same as described above, and R ₄ represents an aryl group which may have a substituent. The aryl group and the substituent are the same as described above. In the general formula (4), Ar, R ₁ and R ₂ are the same as those described above, and R ₅ is an arylene group obtained by taking one bonding group from R ₄ . In the production of the compound of the general formula (4) according to the present invention, the compound of the general formula (4) is obtained by stirring a solution of the compound of the general formula (3) in an organic solvent such as acetonitrile from which water has been removed. That is. The amount of water contained in the organic solvent is preferably 1% by weight or less, more preferably 0.1% by weight or less. 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 (4) according to the present invention are described below.
Tables 1 and 2 show typical structures of the above. In addition, in Table 1, R ₃ corresponds to R ₄ (an aryl group which may have a substituent) in a lower concept, and therefore all the compounds in Table 1 are representative examples of the general formula (3).

[0016]

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[0017]

[Table 1]

[0018]

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[0019]

[Table 2]

[0020]

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

Synthesis Example 1 (Production of Compound No. 1) 4
-Nitrobenzenediazonium tetrafluoroborate
1.37 g and 1.50 g of 4-bromo-N-benzylideneaniline
And dissolved in 50 ml of dry acetonitrile,
For 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) 4
-Nitrobenzenediazonium tetrafluoroborate
1.11 g and 1.20 g of N-diphenylideneaniline are 60 m
Dissolved in 1 liter of dry acetonitrile and stirred at 5 ° C. for about 24 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. 9) 4
-Nitrobenzenediazonium tetrafluoroborate
1.50 g with N- (2-hydroxybenzylidene) aniline
1.25 g was dissolved in 50 ml of acetonitrile and stirred at 5 ° C. for about 5 hours. After the reaction, the generated precipitate is filtered,
Purification by recrystallization method with acetonitrile, yellow crystals
0.70 g was obtained. Yield: 24%, melting point: 209-211 ° C.
MS (m / e): 346 (M ^<+> )

[0024]

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] 1. The following general formula (3): (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 ₄ represents an aryl group which may have a substituent; X ⁻ represents a counter anion; and the azo compound represented by the formula (I) is subjected to a rearrangement reaction. The following general formula (4) (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. And R ₅ represents an arylene group having one bonding group from R ₄ ).