JPS6160833B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a dye intermediate. 5-Nitro-
The present invention relates to a method for producing a benzoxazolone compound and a 6-nitrobenzoxazolone compound useful as a raw material for a 2-aminophenol compound.

For more details, see 1. General formula [In the formula, X and Y each independently represent a hydrogen atom, a halogen atom, or an alkyl group or alkoxy group having each of _C1 to _C4 carbon atoms. ] The 0-aminophenol compound is heated at 100° to 200°C in an organic solvent with a boiling point of 100°C or higher and urea at a ratio of 1.0 to 1.5 mol per 1 mol of the 0-aminophenol compound.
It is characterized by reacting at a temperature of

general formula [In the formula, X and Y mean the above-mentioned ones. ] Method 2 for producing a benzoxazolone compound represented by the general formula [In the formula, X and Y each independently represent a hydrogen atom, a halogen atom, or an alkyl group or alkoxy group each having a C ₁ to _{C 4} carbon atom. ] The 0-aminophenol compound is heated at 100° to 200°C in an organic solvent with a boiling point of 100°C or higher and urea at a ratio of 1.0 to 1.5 mol per 1 mol of the 0-aminophenol compound.
React at a temperature of General formula [In the formula, X and Y mean the above-mentioned ones. ] Production of a benzoxazolone compound represented by
A formula characterized in that the product is then removed once and nitrated using nitric acid in an organic solvent, or the product is not removed and subsequently nitrated using nitric acid in the same bath. [In the formula, X and Y mean the above-mentioned ones. ] It is related with the manufacturing method of the 6-nitrobenzoxazolone compound shown by these.

Conventional methods for synthesizing benzoxazolone from 0-aminophenol include: A: Heat-melting 0-aminophenol hydrochloride with urea (B (Berichte) 19 , 2656) B: Synthesis by reacting 0-aminophenol with phosgene How to do it (Journal of Chemical.
Society 1926, page 821, and PB report (FIAT Final Report 70361P7001) are publicly known.

In addition, as a method for synthesizing 6-nitrobenzoxazolone from benzoxazolone, C is a method in which benzoxazolone is dissolved in concentrated sulfuric acid and nitrated with nitric acid.
Final Report) 70361P7002) D Benzoxazolone in an organic solvent (glacial acetic acid, ethylene chloride, preferably 1,2-dichloroethane, 1,1,2,2- which can form an azeotrope with water and distill off the water) Method of nitration in tetrachloroethane)
135967) is publicly known.

However, these methods have many drawbacks. The melt reaction of A with urea requires the use of a large excess of urea, which makes stirring and discharging difficult, and also produces biurets.

The reaction of B with phosgene is not easy to handle due to its toxicity.

The nitration method of C produces a large amount of waste acid, and waste liquid treatment is not easy.

A further problem is that it is necessary to take out the benzoxazolone, dry it, and then nitrate it.

In Method D, with the intention of improving C, drying of benzoxazolone is omitted and the water-containing presscake is used for nitration, but as with C, the removal of benzoxazolone cannot be omitted.

The inventor uses an aminophenol compound as a raw material,
The 6-
They have discovered a manufacturing method that allows nitrobenzoxazolone to be synthesized easily and inexpensively in good yields and does not have any of the drawbacks of known methods. In the 0-aminophenol compound used as a starting material, the phenyl group may be substituted with a halogen atom, or an alkyl group or alkoxy group having _C1 to _C4 carbon atoms. Of particular interest in the method of the present invention is 0
-aminophenol and 4-chloro-2-aminophenol. The organic solvent with a boiling point of 100°C or higher used in the synthesis of the benzoxazolone compound is preferably an aromatic or aliphatic halogenated hydrocarbon, such as chlorobenzene, 0-dichlorobenzene, P-dichlorobenzene, or dichlorobenzene. (isomer mixture) 1,2,4-triclobenzene, 1,1,2-trichloroethane, 1,1,
2,2-tetrachloroethane, 1,1,1,2-
Tetrachloroethane is used, and nitrobenzene, toluene, 0-xylene, m-xylene, P
-Xylene and mixtures of xylene isomers can also be used.

The amount of urea used is 1.0 to 1.5 mol, preferably 1.2 mol, per mol of 0-aminophenol.

The reaction temperature for the synthesis of benzoxazolone compounds is
The temperature is between 100° and 200°C, preferably between 120° and 180°C. In addition, in order to prevent the oxidation of aminophenols during the synthesis of benzoxazolone compounds, it is preferable to use nitrogen gas,
A benzoxazolone compound of good quality can be obtained by carrying out the process under a stream of carbon dioxide gas or by adding a small amount of acid (for example, hydrogen chloride or sulfuric acid).

As the organic solvent for nitration of the benzoxazolone compound, any of the solvents used for the synthesis of the benzoxazolone compound described above can be used, but chlorobenzene, 0-dichlorobenzene,
These include P-dichlorobenzene, a mixture of dichlorobenzene isomers, and the like.

The reaction conditions for nitration can be varied within a wide range. The nitration temperature is 40° to 140°C, preferably 70° to 120°C.

The concentration of nitric acid is 60 to 100%, preferably 90 to 100%, and the amount of nitric acid used is preferably 1.0 to 2.0 mol relative to the raw material aminophenol. By adding a small amount of sulfuric acid before nitration, the amount of nitric acid is 1.0%. It is also possible to set it to ~1.3 mol. After nitration, the 6-nitrobenzoxazolone compound generally exists in the form of crystals and can be isolated by suction filtration either as is or after adding water. According to the present invention, high yield and high purity benzoxazolone compounds and 6-nitrobenzoxazolone compounds can be obtained through simple steps. The nitrated product thus obtained is converted into 5-nitro-2-aminophenol by saponification, for example, in the case of 6-nitro-benzoxazolone.
In the case of -chloro-6-nitro-benzoxazolone, it can be easily converted to 4-chloro-5-nitro-2-aminophenol in good yield.

The following examples and percentages represent parts by weight and percentages by weight unless otherwise specified.

Example 1 21.8 parts of 0-aminophenol and 14.4 parts of urea are heated in 100 parts by volume of chlorobenzene at 130-135° C. for 5 hours while blowing nitrogen gas. The reaction solution is cooled to room temperature, made acidic by adding a small amount of sulfuric acid, and vacuumed. The excess residue is washed with 50 parts of water and then dried to obtain benzoxazolone.

Yield: 24.1 parts (89% of theory) Melting point: 139° to 140°C Example 2 28.7 parts of 2-amino-4-chlorophenol and 14.4 parts of urea were mixed in 130 to 100 parts by volume of chlorobenzene.
Heat at 135°C for 5 hours. The reaction solution was cooled to room temperature, and 50 parts of water were added thereto, followed by a small amount of hydrochloric acid to make it weakly acidic, stirred for a while, and then filtered under suction. After washing the excess residue with a small amount of water and drying, 29.5 parts of 5-chlorobenzoxazolone (87% of theory) are obtained.

Melting point: 187-188℃ Elemental analysis value C (%) H (%) N (%) Cl (%) Calculated value 49.56 2.36 8.26 20.94 Actual value 49.47 2.12 8.33 20.68 Example 3 2-amino-4,6-dibrome Phenol 53.4
and 14.4 parts of urea in 100 parts by volume of 1,1,1,2-tetrachloroethane while blowing nitrogen gas to 130 parts.
Heat at ℃ for 5 hours. The reaction solution is cooled to room temperature, made acidic by adding a small amount of sulfuric acid, and filtered with suction. The residue is washed with water and dried to obtain 49.8 parts of 5,7-dibromobenzoxazolone (85% of theory).

Melting point: 248-250°C Example 4 21.8 parts of 0-aminophenol and 14.4 parts of urea are heated in 100 parts by volume of chlorobenzene at 130-135°C for 5 hours.

After cooling the reaction solution to 70°C, 10 parts of concentrated sulfuric acid was added. Subsequently, 18 parts of 90% nitric acid are added dropwise over 1 hour at 80-90°C. After the completion of the dropwise addition, stirring was continued at the same temperature for 2 hours, then cooled to room temperature and filtered under suction. Remove excess residue with water
After washing with 50 parts and drying, 31.0 parts of 6-nitrobenzoxazolone (86.1% of theory) are obtained.

Melting point: 240-242°C Example 5 A small amount of Perex OT-P (manufactured by Kao Atlas Co., Ltd.) was added to the benzoxazolone reaction solution obtained in the same manner as in Example 4, and 32.4 parts of 70% nitric acid was added to the solution while maintaining the temperature at 80-90°C. Add dropwise over time. After the completion of the dropwise addition, stirring was continued at the same temperature for 2 hours, then cooled to room temperature and filtered under suction. The excess residue is washed with 50 parts of water and then dried. 6
- 30.5 parts of nitrobenzoxazolone (theoretical
84.7%).

Example 6 28.7 parts of 2-amino-4-chlorophenol and 14.4 parts of urea are heated in 100 parts by volume of chlorobenzene at 130-135° C. for 5 hours while blowing nitrogen gas. The nitrogen gas blowing was stopped, the reaction solution was cooled to 70°C, and 25 parts of 90% nitric acid was added dropwise over 1 hour while maintaining the temperature at 80-90°C. After completion of the dropwise addition, stirring was continued at the same temperature for 2 hours, then cooled to room temperature and filtered under suction. The excess residue is washed with 50 parts of water and then dried. 35.8 parts (83.4% of theory) of 5-chloro-6-nitrobenzoxazolone are obtained.

Melting point: 205° to 207°C Example 7 Same as Example 4 except that 24.6 parts of 4-methyl-2-amino-phenol or 27.8 parts of 4-methoxy-2-aminophenol was used instead of 21.8 parts of 0-aminophenol. 5-methyl-6-
32.0 parts of nitrobenzoxazolone and 32.8 parts of 5-methoxy-6-nitrobenzoxazolone were obtained, respectively.

Claims (1)

[Claims] 1. General formula [In the formula, X and Y each independently represent a hydrogen atom, a halogen atom, or an alkyl group or alkoxy group having _C1 to _C4 carbon atoms. ] The 0-aminophenol compound is heated at 100° to 200°C in an organic solvent with a boiling point of 100°C or higher and urea at a ratio of 1.0 to 1.5 mol per 1 mol of the 0-aminophenol compound.
It is characterized by reacting at a temperature of general formula [In the formula, X and Y mean the above-mentioned ones. ] Method 2 for producing a benzoxazolone compound represented by the general formula [In the formula, X and Y each independently represent a hydrogen atom, a halogen atom, or an alkyl group or alkoxy group having _C1 to _C4 carbon atoms. ] The 0-aminophenol compound is heated at 100° to 200°C in an organic solvent with a boiling point of 100°C or higher and urea at a ratio of 1.0 to 1.5 mol per 1 mol of the 0-aminophenol compound.
The general formula is reacted at a temperature of [In the formula, X and Y mean the above-mentioned ones. ] Produce a benzoxazolone compound represented by
A formula characterized in that the product is then removed once and nitrated using nitric acid in an organic solvent, or the product is not removed and subsequently nitrated using nitric acid in the same bath. [In the formula, X and Y mean the above-mentioned ones. ] A method for producing a 6-nitrobenzoxazolone compound shown in the following.