JPH05140120A - New production of 2-hydroxyquinoxaline - Google Patents

Abstract

PURPOSE:To industrially and advantageously obtain 2-hydroxyquinoxaline useful as an intermediate for agricultural chemicals, medicines and dyes, etc., in high purity and yield with industrial advantages such as facilitated recovery of a solvent or simple heat removing operation. CONSTITUTION:O-Phenylenediamine is made to react with a compound expressed by the formula (R1 and R2 are 1-5C alkyl or alkenyl) in a molar amount of preferably 1.0-1.2 times based on the o-phenylenediamine in a solvent (preferably a lower aliphatic alcohol) at -20 to +80 deg.C, preferably 10-50 deg.C temperature to provide 2-hydroxyquinoxaline. The compound expressed by the formula is preferably dropped into a mixture solution of the lower aliphatic alcohol with the o-phenylenediamine to carry out the reaction. Since an acid catalyst is not used in this method, the solvent can readily be recovered. Since an aqueous solution of glycolic acid is not used, the content of the solvent can be increased. Furthermore, since the reactional temperature can be set at a relatively high value, the viscosity of the reactional solution is low and heat removing operation is simply performed.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing 2-hydroxyquinoxaline, which is useful as an intermediate for producing agricultural chemicals, pharmaceuticals, dyes and the like.

[0002]

2. Description of the Related Art A method of reacting glyoxylic acid and orthophenylenediamine in a dimethylformamide solvent at a temperature of -10 DEG C. [C. A. , 88, 121243g, (197
8)]. Japanese Patent Publication No. 61105/1989 describes a method of reacting glyoxylic acid with orthophenylenediamine in a lower aliphatic alcohol solvent in the presence of a formic acid or acetic acid catalyst. In addition, JP-A-2-
286667 describes a modification of the above method. Further, a method using glyoxylic acid ethyl ester is also described in J. Chem. Soc., 622 (1945).

[0003]

The method using a dimethylformamide solvent is expensive and has a high boiling point, so that the method on an industrial scale requires a special reaction apparatus or a solvent recovery method. It is not satisfactory due to heavy load. Further, in the method using a formic acid or acetic acid catalyst, since the acid catalyst used is mixed in the filtrate obtained by filtering off the target crystal, a solvent (lower aliphatic alcohol-
It is difficult to collect only).

When the yield is about 90% or less, reaction residues such as by-products are increased, and the amount of industrial waste is increased. Further, the viscosity of the reaction product is high and it is difficult to remove heat in a low temperature reaction. Thus, the conventional method has a fatal defect in industrial production.
Therefore, it has been desired to develop a manufacturing method that improves the yield and facilitates heat removal operation, powder handling, and solvent recovery.

[0005]

The inventors of the present invention have described the general formula

[Chemical 2] A glycolic acid ester derivative of the formula (wherein R ₁ and R ₂ each independently represent a lower alkyl or lower alkenyl group having 1 to 5 carbon atoms, which may be the same or different) is reacted with orthophenylenediamine in a solvent. Thus, a method for producing 2-hydroxyquinoxaline having a higher yield than the conventional method was found.

In the present invention, since an acid catalyst is not used, the solvent can be easily recovered, and the object can be achieved industrially advantageously. Further, since the aqueous solution of glycolic acid is not used, the content of the solvent can be increased. Since the reaction temperature can be set to a relatively high place, the viscosity of the reaction solution is extremely low and the efficiency of heat removal is considerably high.

Examples of the solvent used in the present invention include methanol, ethanol, propanol and isopropanol.
Examples of the solvent include lower aliphatic alcohol solvents such as alcohol and butanol, mixed solvents of these solvents and water, and polar solvents that are inert to amines, but dissolve orthophenylenediamine and glycolic acid ester derivatives. Alternatively, it is not limited to these as long as they are dispersed. The amount of the solvent used is not particularly limited, but the reaction rate becomes slow when used in a large amount, so
Preferably 30 per mol of ortho-phenylenediamine
0 to 1000 ml is good.

The amount of the glyco-ester derivative is not particularly limited, but it is 1.0 or less with respect to orthophenylenediamine.
It is preferable to use 1.2 to 1.2 times mol. The reaction temperature is not a particularly important factor, but the reaction temperature is −20 ° C. to 80 ° C., preferably 10 ° C. to 50 ° C. The reaction involves the glyco-formation of ortho-phenylenediamine into, for example, an alcohol solution.
It is preferable that the derivative of the acid ester is added dropwise.
A reaction time of 1 to 5 hours is sufficient. Since the method of the present invention provides a high-purity product, it is not necessary to carry out purification such as activated carbon treatment or recrystallization.

[0009]

INDUSTRIAL APPLICABILITY According to the present invention, a product with high purity and high yield can be obtained by reacting orthophenylenediamine with a glyco-acid ester derivative, and since an acid catalyst is not used, solvent recovery is easy. In addition, the reaction liquid has a low viscosity, the heat removal operation is simple, and industrially advantageous production is possible.

[0010]

EXAMPLES The effects of the present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Example 1 Ortho-phenylenediamine 43.6 in 200 ml methanol
g (purity 99.2%) was dissolved, and 49.0 g of methyl 2-methoxy-glycolate was added dropwise thereto at 30 ° C. over 1 hour.
Then react at 50 ° C. for 1 hour and filter the product at 8 ° C.
After washing with methanol and drying, 57.3 g of the desired product was obtained. The purity was 99.6% as determined by the internal standard method using a high performance liquid chromatograph. The yield was 97.6% based on orphenylenediamine. This product has a melting point of 268-270 ° C.
Met.

Example 2. Example 1. Where, methano-
The reaction and post-treatment were carried out in the same manner using ethanol instead of ethanol to obtain 56.7 g of the desired product. Purity is 99.5%, yield is
It was 96.5%. The melting point was 268-270 ° C.

Embodiment 3. In Example 1, a 95 wt / wt% methanol aqueous solution was used instead of methanol, and the same reaction and post-treatment were carried out to obtain 56.6 g of the desired product. Purity is 9
The 9.5% yield was 96.3%. The melting point was 268-270 ° C.

Example 4. Example 1. In the above, the dropping temperature was changed to 50 ° C. instead of 30 ° C., and the same reaction and post-treatment were carried out to obtain 56.7 g of the desired product. Purity 99.5%, yield 9
It was 6.5%. The melting point was 268-270 ° C.

Reference Example 1. Ortho-phenylenediamine 53.6
g (purity 99.2%) was taken in a reaction vessel, 250 ml of methanol was added, and the mixture was cooled to 4-6 ° C. 97.2 g of 40% glyoxylic acid is added dropwise at the same temperature over 2 hours. After dropping, the mixture is aged at the same temperature for 30 minutes, then heated to 50 ° C. and further aged at the same temperature for 1 hour. The product was cooled to room temperature, filtered, and dried to obtain 56.0 g of the desired product. The purity was 93.4% and the yield was 71.6%. The melting point was 266-268 ° C.

Reference Example 2. Orthophenylenediamine 10.8
0 g (0.100 mol) is placed in a reaction vessel, 75 ml of methanol and 1 ml of acetic acid are added, and the mixture is cooled to -4 to -6 ° C with stirring. 40%
After adding 19.45 g (0.105 mol) of glyoxylic acid at the same temperature over about 1 hour, the mixture was reacted at the same temperature for 2 hours. After the reaction
The product is collected by filtration at the same temperature, washed with methanol and dried to obtain 12.91 g of 2-hydroxyquinoxaline. purity
98.5%. Yield 87.0%. The melting point of this product was 268 to 270 ° C.

Claims (4)

[Claims] 1. Ortho-phenylenediamine and a general formula: 2-hydroxyquinoxaline characterized by reacting a compound represented by the formula (wherein R ₁ and R ₂ are the same or different C ₁ -C ₅ lower alkyl or lower alkenyl group) in a solvent. Manufacturing method. 2. The method according to claim 1, wherein the solvent is a lower aliphatic alcohol. 3. The method according to claim 2, wherein the compound of the formula (1) is added dropwise to a mixed solution of a lower aliphatic alcohol and orthophenylenediamine for reaction. 4. The method according to claim 1, 2 or 3, wherein the reaction is carried out at a reaction temperature of −20 ° C. to 80 ° C.