JPH1112238A - Production of 1-(beta-hydroxyethyl)-2,5-diaminobenzene or its salt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce the subject compound useful as a raw material for dyes, pigments, polymers and agrochemicals in high selectivity and high yield by reducing a specific phenylacetic acid derivative using two kinds of reducing means. SOLUTION: 2-Amino-5-nitrophenylacetic acid represented by formula I is reduced with a metal hydride (e.g. sodium borohydride) in a molar amount of preferably 0.05-10 times based on the compound represented by formula I to provide 1-(β-hydroxyethyl)-2-amino-5-nitrobenzene represented by formula II, which is then catalytically reduced to afford the subject compound represented by formula III. The compound represented by formula I can easily be obtained by nitrating inexpensive and readily available 2-chlorophenylacetic acid with concentrated sulfuric acid-fuming nitric acid, providing 2-chloro-5- nitrophenylacetic acid and then reacting the resultant compound with aqueous ammonia in the presence of a copper salt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing 1- (β-hydroxyethyl) -2,5-diaminobenzene or a salt thereof, which is an important compound as a raw material for dyes, pigments, polymers and agricultural chemicals.

[0002]

2. Description of the Related Art 1- (β-hydroxyethyl) -2,5
-Diminobenzene or a salt thereof is known to be useful as a precursor for an oxidative hair dye (WO90)
/ 14818). And, as the manufacturing method, 2-
After reacting acetic anhydride with (2-aminophenyl) ethanol, it is nitrated to give N-acetyl-2- (2-acetoxyethyl) -4-nitroaniline and N-acetyl-2- (2-acetoxyethyl). A mixture of -5-nitroanilines is obtained, which is hydrolyzed by reacting with hydrochloric acid to give 2
A mixture of-(2-amino-5-nitrophenyl) ethanol and 2- (2-amino-4-nitrophenyl) ethanol was obtained, from which 2- (2-amino-5-nitrophenyl) ethanol was separated. A method for post-catalytic reduction is known (WO 90/14818).

[0003]

However, in this production method, 2- (2-aminophenyl) ethanol used as a raw material is very expensive and difficult to obtain, and the yield is not sufficiently satisfactory. Accordingly, an object of the present invention is to provide a method for producing 1- (β-hydroxyethyl) -2,5-diaminobenzene or a salt thereof with high selectivity and high yield from inexpensive and easily available raw materials. .

[0004]

The inventors of the present invention have made various studies to solve the above-mentioned problems, and as a result, have found that 2-amino-aminoacetic acid which is easily obtained from 2-halogenophenylacetic acid which is inexpensive and easily available by a known method. The inventors have found that 1- (β-hydroxyethyl) -2,5-diaminobenzene can be obtained in high yield by reducing 5-nitrophenylacetic acid using two types of reduction means, and completed the present invention. Was.

The method of the present invention is represented by the following reaction formula.

[0006]

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That is, according to the present invention, 2-amino-5-nitrophenylacetic acid (1) is reduced using a metal hydride to form 1- (β-hydroxyethyl) -2-amino-5-nitrobenzene (2). 1- (β-hydroxyethyl) -2,5
A process for producing diaminobenzene (3) or a salt thereof.

[0008]

DETAILED DESCRIPTION OF THE INVENTION 2-Amino-5-nitrophenylacetic acid (1), which is a starting compound in the present invention, is obtained by nitrating 2-chlorophenylacetic acid, which is inexpensive and easily available, using concentrated sulfuric acid-fuming nitric acid. It can be easily produced by reacting 2-chloro-5-nitrophenylacetic acid with aqueous ammonia in the presence of a copper salt (Japanese Patent Application Laid-Open No. Hei 8-134024).

A metal hydride is used for the reduction reaction of 2-amino-5-nitrophenylacetic acid (1). The metal hydride used in this reaction is preferably sodium borohydride in terms of functional group selectivity and ease of handling. The amount of the metal hydride to be used is preferably 0.5 to 10 mol, more preferably 0.6 to 1.5 mol, per mol of compound (1). The reactivity of a metal hydride is significantly improved by coexisting with aluminum chloride. The amount of aluminum chloride to be used is preferably 0.2 to compound (1).
It is 5 to 5 moles, preferably 0.2 to 0.5 moles. The reaction temperature is generally 0-160 ° C, preferably 50-1.
00 ° C. The solvent used in the reaction is not particularly limited as long as it does not adversely affect the reaction, but ether solvents such as tetrahydrofuran, dioxane, ethylene glycol diethers, and diethylene glycol diether, toluene, xylene, benzene, hexane, and cyclohexane. Hydrocarbon solvents can be used, and ether solvents are preferred. From the viewpoint of the solubility of the substrate, ethylene glycol dimethyl ether is more preferable.

The reduction reaction of 1- (β-hydroxyethyl) -2-amino-5-nitrobenzene (2) uses catalytic reduction. Examples of the metal catalyst used for the reaction include metal catalysts usually used for a reduction reaction of a nitro group, and palladium carbon is preferable. Hydrogen pressure is 1-100kg /
cm ² , preferably 30 to 70 kg / cm ² . 1- (β-
(Hydroxyethyl) -2,5-diaminobenzene (3)
Any of an organic acid such as succinic acid and an inorganic acid such as hydrochloric acid and sulfuric acid may be used to obtain a salt of 1- (β-hydroxyethyl) -2,5-diaminobenzene simply by adding an acid after completion of the reaction. The salt of (3) precipitates.

[0011]

Next, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

Example 1 1- (β-hydroxyethyl)
Synthesis of 2-amino-5-nitrobenzene 2-amino-5-nitrophenylacetic acid (0.98 g,
5.0 mmol), sodium borohydride (0.17 g,
To a solution of 4.5 mmol) in diethylene glycol dimethyl ether (5 ml) was added aluminum chloride (0.20 g, 1.
5 mmol) of diethylene glycol dimethyl ether (9
ml) solution was added dropwise. After stirring at 75 ° C. for 4 hours, the reaction product was extracted with ethyl acetate and washed with water and saturated saline. After evaporating the solvent under reduced pressure, the residue was purified by silica gel column chromatography, and 1- (β-hydroxyethyl) was obtained as a yellow powder.
-2-Amino-5-nitrobenzene (0.26 g, 30% yield) was obtained.

¹ H-NMR (ACET-D ₆ ) δ ppm: 2.75-2.86 (m, 2H),
3.78-3.91 (m, 2H), 3.94-4.05 (m, 1H), 5.93 (brs, 2H), 6.7
6 (d, J = 8.8Hz, 1H), 7.88 (dd, J = 8.8, 2.7Hz, 1H), 7.96 (d, J
= 2.7Hz, 1H) IR (KBr neat) νcm ^-1 : 3472, 3356, 3228, 2928, 2888,
1668, 1608, 1584,1482, 1442, 1306, 1288, 1152, 110
0, 1040, 908,816, 754, 730, 646, 614, 556, 482, 42
8

Example 2 1- (β-hydroxyethyl)
Synthesis of 2,5-diaminobenzene sulfate 1- (β-hydroxyethyl) -2 in an autoclave
-Amino-5-nitrobenzene (204 mg, 1.1 mmol
l) 5% palladium on carbon (22 mg) in ethanol (2
(0 ml), hydrogen (50 kg / cm ² ) was injected into the solution, and the mixture was stirred at 50 ° C. for 5 hours. After completion of the reaction, the catalyst was removed by filtration, and sulfuric acid (118 mg, 1.2 mmol) was added. The precipitated solid is separated by filtration and dried under reduced pressure to obtain 1 white powder.
Thus,-(β-hydroxyethyl) -2,5-diaminobenzene sulfate (244 mg, yield: 87%) was obtained. mp 222.5-224.5 ° C

[0015]

According to the method of the present invention, 1- (β-hydroxyethyl) -2,5-diaminobenzene or a salt thereof can be obtained with high yield and high selectivity.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshiaki Fujikura 2606 Akabane, Kaiga-cho, Haga-gun, Tochigi Pref.

Claims (1)

[Claims] 1. Reduction of 2-amino-5-nitrophenylacetic acid with a metal hydride to 1- (β-hydroxyethyl) -2-amino-5-nitrobenzene, which is then catalytically reduced. A method for producing 1- (β-hydroxyethyl) -2,5-diaminobenzene or a salt thereof, which is a feature.