JPH0667881B2 - 5-Bromo-4-chloro-2-fluoroaniline and process for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to 5-bromo-4-chloro-2-fluoroaniline (hereinafter referred to as the compound of the present invention) and a method for producing the same.

The compound of the present invention has the general formula [I] having herbicidal activity. [In the formula, R represents a hydrogen atom, an alkyl group or a phenyl group. ] It is a compound useful as a production intermediate of a tetrahydrophthalimide derivative represented by

The present inventors have investigated the method for producing a compound represented by the general formula [I] having herbicidal effect, and found that the compound of the present invention, 5-bromo-4-chloro-2-fluoroaniline, has the above general formula [I]. ] It is important as an intermediate of the compound represented by the above and that the compound of the present invention can be advantageously produced by reducing 1-bromo-2-chloro-4-fluoro-5-nitrobenzene with a reducing agent such as iron powder. The present invention has been found.

The production method of the compound of the present invention is described below.

In the production method of the present invention, the amount of the reagent used in the reaction is
With respect to 1 equivalent of 1-bromo-2-chloro-4-fluoro-5-nitrobenzene, the reducing agent such as iron powder is 3 to 30 equivalents, preferably 5 to 20 equivalents. In the present invention,
The reaction temperature is 60 to 120 ° C., and the reaction time is usually 1
The purpose can be achieved sufficiently in about 20 hours. The reaction of the present invention is carried out, for example, in an acetic acid aqueous solution, if necessary, in the presence of an auxiliary solvent such as ethyl acetate. After completion of the reaction, the reaction solution is passed over to remove insoluble materials, the solution is extracted with an organic solvent that is sparingly soluble in water, and the extract is washed with water and then subjected to usual post-treatment operations such as concentration, or further, if necessary, The target 5-bromo-4 is obtained by a usual purification operation such as recrystallization or chromatography.
-Chloro-2-fluoroaniline can be obtained.

From the compound of the present invention obtained by the production method of the present invention, for example, a compound having the herbicidal effect represented by the general formula [I] can be obtained by the following route.

In addition, 1-bromo-2-chloro-4-fluoro-5 which is a raw material of 5-bromo-4-chloro-2-fluoroaniline
-Nitrobenzene can be obtained by the following production method.

That is, 1.0 equivalent of 1 equivalent of 2-chloro-4-fluoroaniline
After diazotization by reacting with about 2.0 equivalents of a diazotizing agent,
1. By reacting 1.0 to 2.0 equivalents of a brominating agent such as cuprous bromide in an aqueous solution such as hydrobromic acid to brominate
-Bromo-2-chloro-4-fluorobenzene is obtained. In the above reaction, the reaction temperature and reaction time are usually in the range of -5 to 5 ° C for diazotization, in the range of 0.5 to 3 hours, and for bromination in the range of 20 to 70 ° C, 1 to 5 respectively.
The purpose can be achieved sufficiently within the range of time.

Then, 1-bromo-2-chloro-4-obtained above
1-Bromo-2-chloro-4 by reacting 1 equivalent or more of sulfuric acid, preferably concentrated sulfuric acid, and 1.0 to 1.2 equivalents of nitric acid, preferably fuming nitric acid, with 1 equivalent of fluorbenzene.
-Fluoro-5-nitrobenzene is obtained.

In the above reaction, the reaction temperature and the reaction time are usually in the range of -10 to 20 ° C and 1 to 10 hours, respectively, and the purpose can be sufficiently achieved.

The above 2-chloro-4-fluoroaniline is obtained by Finger et
Al., J. Am. Chem. Soc., 81 , 94 (1959).

Hereinafter, the present invention will be described in more detail with reference to Examples and Reference Examples.

Example 20 g of iron powder was suspended in 50 m of 5% acetic acid water and heated to 80 ° C. A solution prepared by dissolving 14 g of 1-bromo-2-chloro-4-fluoro-5-nitrobenzene in 20 m of acetic acid and 80 m of ethyl acetate was added thereto, and the mixture was heated at 60 ° C to 80 ° C.
The mixture was heated to reflux at 8 ° C for 8 hours. After cooling, water and ethyl acetate were added, the residue was separated, and the liquid was extracted with ethyl acetate.
Wash the extract with water, then sodium bicarbonate water, dry and concentrate
10.4 g of bromo-4-chloro-2-fluoroaniline was obtained.

mp67.0-68.6 ° C Reference example 1 58 g of 2-chloro-4-fluoroaniline was added to concentrated sulfuric acid 12
Dissolve in a mixture of 0 g and 160 m of water, -5 ° C to 0
A solution of 28 g of sodium nitrite in 100 m of water was added at 0 ° C, and the mixture was stirred for 20 minutes at the same temperature. Excess nitrous acid in the reaction solution was removed by adding sulfamic acid to the reaction solution until the color of the potassium iodide starch paper disappeared, and the resulting diazonium solution was odorized with 68 g of cuprous bromide at 48%. It was added at room temperature to a solution dissolved in 500 m of an aqueous solution of hydrofluoric acid, and stirred at 30 to 40 ° C for 30 minutes. This reaction mixture was extracted with ether, and the ether layer was washed with water, dried, concentrated, and distilled to obtain 76 g of 1-bromo-2-chloro-4-fluorobenzene. bp62.0 ~ 62.8 ℃ /
12 mmHg Reference Example 2 1-Bromo-2-chloro-4-obtained in Reference Example 1 above
21 g of fluorobenzene was dissolved in 40 m of concentrated sulfuric acid. This is cooled to 0 ° C to 10 ° C and fuming nitric acid (d = 1.5
2) A mixture of 8.2 g and concentrated sulfuric acid 5 m was gradually added dropwise at 0 ° C to 5 ° C, and the mixture was stirred at the same temperature for 30 minutes. The reaction mixture was poured into ice water and extracted with ether. Wash the extract with water,
It was dried and concentrated to obtain 14.3 g of 1-bromo-2-chloro-4-fluoro-5-nitrobenzene. mp6 5.0-6
5.5 ° C.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masayuki Takase 4-2-1 Takashi, Takarazuka-shi, Hyogo Sumitomo Kagaku Kogyo Co., Ltd. (56) Reference JP-A-60-228494 (JP, A)

Claims (2)

[Claims] 1. 5-Bromo-4-chloro-2-fluoroaniline 2. 1-Bromo-2-chloro-4-fluoro-
Method for producing 5-bromo-4-chloro-2-fluoroaniline, characterized by reducing 5-nitrobenzene