JPH09291068A - Production of halogenated anthraquinone-based compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a compound useful as an intermediate for dyes in high purity and yield without any concern about carcinogenicity, etc., through preventing by-product formation. SOLUTION: This halogenated anthraquinone-based compound of formula II (X is a halogen) is obtained by reaction of a 1-amino-2anthraquinonecarboxylic acid-based compound of formula I (R is H, an alkyl or alkoxy) with a halogenating agent in an aprotic polar solvent (e.g. N,N-dimethylformamide) at 20-100 deg.C for 2-6h. The amounts of the solvent and the halogenating agent (e.g. bromine as simple substance) to be used are 3-2wt. times and 1.5-2.5 molar times the compound of formula I, respectively, and the halogenating agent is charged into the reaction system at a rate of 0.01-0.03wt. times/min.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a halogenated anthraquinone compound useful as an intermediate for a dye.

[0002]

2. Description of the Related Art Halogenation of organic compounds is a well-known reaction, and various methods for halogenating aromatic rings have been reported with regard to halogenating agents and reaction solvents used. 1-Amino-2-anthraquinonecarboxylic acid compounds are compounds that are relatively difficult to halogenate because they have an electron-donating amino group and an electron-withdrawing carboxyl group on the same ring, and are generally reactive. The method applied to the halogenation of a rich aromatic ring does not give favorable results.

The halogenation reaction is carried out by dissolving or suspending the starting compound in a suitable solvent. Organic reaction solvents include 1,4 dioxane, nitrobenzene and o.
-Dichlorobenzene and the like are known. Although 1,4 dioxane dissolves raw materials well and has a good yield, its carcinogenicity to animals is pointed out and there are various restrictions on its use.

On the other hand, when nitrobenzene or o-dichlorobenzene is used as a solvent, it is difficult to completely dissolve the raw material, and the raw material is not completely dissolved unless a large excess amount is used. Therefore, if the solution is attempted to be completely dissolved, the productivity will deteriorate. In a system which is not completely dissolved, the reaction is not completed because the product encloses the raw material and the yield is poor. Also, odor becomes a problem when scaled up. Highly soluble N, N-dimethylformamide and the like have been pointed out to have a risk of contact with bromine ("Handbook of Contact Danger of Chemicals" published by Nikkan Kogyo Shimbun) and have not been used for halogenation.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a method for producing a halide of 1-amino-2-anthraquinonecarboxylic acid in a high yield by using a solvent which is safe for the human body and easy to handle. With the goal.

[0006]

The inventors of the present invention can handle bromine and N, N-dimethylformamide, which have been pointed out to be in danger of contact with each other, without risk and can handle them with high yield. The present invention has been accomplished by finding that the desired halide can be obtained at a specific rate. That is, the gist of the present invention is:
The 1-amino-2-anthraquinonecarboxylic acid compound represented by the general formula [I] is brought into contact with a halogenating agent in an aprotic polar solvent, and is represented by the general formula [II]. It exists in a method for producing a halogenated anthraquinone compound.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The compound of the general formula [I] used as a raw material is 1-amino-2-anthraquinonecarboxylic acid or a lower alkyl group such as methyl, ethyl, propyl or butyl, or methoxy, ethoxy or butoxy. Having a lower alkoxy group such as
-Amino-2-anthraquinonecarboxylic acids. As the aprotic polar solvent, N-methyl-2-
Pyrrolidone, N, N-dimethylformamide, hexamethylphosphoamide and other amides, dimethyl sulfoxide nitromethane and the like can be mentioned. Above all, amides, especially N
-Methyl-2-pyrrolidone and N, N-dimethylformamide are preferable in terms of safety and handleability.

The amount of the solvent used is not particularly limited, but it is not preferable if the amount is too large because it is disadvantageous in cost. On the contrary, if the amount is too small, the raw materials are not completely dissolved, and the reaction system becomes non-uniform, which is not preferable. Usually, the compound of the general formula [I] is used in an amount of 3 to 20 times (weight ratio) with 1 being the amount. As the halogenating agent, halogen simple substances such as chlorine and bromine as well as sulfuryl chloride and N-bromosuccinimide are used.

The amount of halogen used is also not particularly limited, but if the amount is equimolar to the compound of the general formula [I], the progress of the reaction will slow down during the reaction, and if it is too large, cost and risk will increase. Use 1.5 to 2.5 times the ratio. The reaction temperature is 20 to 100 ° C., but it is not preferable if the temperature is too high, because a dangerous situation occurs or a side reaction occurs and the reaction becomes difficult to proceed. On the other hand, if the temperature is too low, the reaction rate becomes slow and the reaction time becomes long. Therefore, it is preferable to react at 40 to 60 ° C.

The halogen charging rate is important in terms of safety and suppression of by-products. Depending on the reaction scale, if the charging speed is too fast, by-products will be produced. If it is too slow, the reaction time is only lengthened, so it is preferable to charge halogen at a rate of 0.01 times by weight / min to 0.03 times by weight / min with the amount of the compound of the general formula [I] being set at 1.

In the present invention, other embodiments are not limited, and a deoxidizing agent or a catalyst may be used. As the method of charging the halogen, a method of charging the compound of the general formula [I] and the solvent all at once, heating the temperature to the reaction temperature, and then charging the halogenating agent may be adopted. The reaction time depends on the amount of halogen (halogenating agent) used and the addition time thereof, but is usually 2 to 6 hours. The mixture after the reaction is the unreacted halogen simple substance (halogenating agent) in the reaction vessel.
Is neutralized with sodium hydrogen sulfite or the like, and hydrogen halide or the like produced in the reaction is treated with sodium hydroxide or the like to be neutralized. Then, demineralized water is added to precipitate crystals. The crystals are collected by filtration, but the filter cake is further washed with water to remove the inorganic salts, etc., which were entrapped during neutralization,
It can be a high-purity product.

[0012]

EXAMPLES Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples unless it exceeds the gist. Example 1 In a glass reactor with temperature controller and stirrer, 1
-Amino-2-anthraquinonecarboxylic acid 160.2
3240 ml of g, N, N-dimethylformamide was charged and the temperature was raised to 50 ° C. to prepare a uniform solution. With stirring, 182.2 g of elemental bromine was mixed into this homogeneous solution over 80 minutes, and then a 4.5 hr reaction was carried out at the same temperature. After completion of the reaction, the mixture was cooled to room temperature, 240 g of sodium hydrogen sulfite was added with stirring, and then 2400 ml of demineralized water was added to precipitate crystals. Next, Nutsche type filter (No. 5C
The crystals of 1-amino-4-bromo-2-anthraquinonecarboxylic acid were collected by filtration with (filter paper). The yield is 98.
8%.

Comparative Example 1 Crystals were recovered in the same manner as in Example 1 except that 3240 ml of N, N-dimethylformamide was replaced with o-dichlorobenzene in the same amount and the reaction temperature was 70 ° C. The yield at that time was 80.3%.

Example 2 The same amount of N-methyl-2-pyrrolidone was used instead of 3240 ml of N, N-dimethylformamide.
Synthesis was performed in the same manner as in Example 1 to recover crystals. The yield at that time was 95.0%.

Comparative Example 2 Crystals were recovered in the same manner as in Comparative Example 1 except that the same amount of nitrobenzene was used instead of 3240 ml of N, N-dimethylformamide. The yield at that time was 85.
2%.

Example 3 Synthesis was performed in the same manner as in Example 1 except that 137.7 g of sulfuryl chloride was used instead of elemental bromine, and crystals of 1-amino-4-chloro-2-anthraquinonecarboxylic acid were recovered. . The yield at that time was 83.2%.

Comparative Example 3 Crystals were recovered in the same manner as in Example 3, except that the same amount of o-dichlorobenzene was used instead of 3240 ml of N, N-dimethylformamide. The yield at that time was 69.7%.

[0018]

EFFECT OF THE INVENTION According to the method of the present invention, the desired 4-halo-1-amino-2 can be obtained with high purity and high yield without fear of carcinogenicity, prevention of by-product formation. An anthraquinone carboxylic acid compound can be obtained.

Claims (3)

[Claims] 1. A compound represented by the following general formula [I] (Wherein R represents a hydrogen atom, an alkyl group or an alkoxy group) is contacted with a halogenating agent in an aprotic polar solvent, and the following general formula [II]: Chemical 2] (In the formula, X represents a halogen atom, and R represents the same as in the general formula [I].) A method for producing a halogenated anthraquinone compound. 2. The method for producing a halogenated anthraquinone compound according to claim 1, wherein the aprotic polar solvent is selected from amides. 3. The method for producing a halogenated anthraquinone compound according to claim 2, wherein the amide is dimethylformamide or N-methyl-2-pyrrolidone.