RU2268877C1 - Method for preparing 2-chloro-4-nitrophenol - Google Patents

Abstract

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to a method for synthesis of organic substances used as active components in treatment of fungal skin damages. In particular, in preparing the preparation "Nitrofungin" method involves using 2-chloro-4-nitrophenol that is synthesized by the chlorination reaction of 4-nitrophenol with sodium hypochlorite by stirring in hydrochloric acid medium at temperature 0°C. The precipitated product is filtered off and dries.

EFFECT: improved preparing method, enhanced yield of end product.

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Description

The invention relates to methods for producing organic substances, in particular 2-chloro-4-nitrophenol, which is used as the active principle of the antifungal drug Nitrofungin. Nitrofungin is used for fungal skin lesions: epidermophytin, trichophytin, fungal eczema, etc.

The drug is produced in Slovakia, there are no analogues in Russia. A known method for producing 2-chloro-4-nitrophenol, which consists in the chlorination of 4-nitrophenol with gaseous chlorine in the presence of acetic acid, patent Czechoslovakia No. 181644, class. C 07 C 79/12, 1980. The disadvantage of this method is the use of gaseous chlorine, which requires special (corrosion-resistant) equipment due to the high aggressiveness of chlorine. In addition, the yield of the target product is low (72.5%).

A known method of producing 2-chloro-4-nitrophenol, RF patent No. 2046794, class. C 07 C 205/26, C 07 B 30/00, 1995. In this method, 4-nitrophenol is mixed with hydrochloric acid. Nitric acid is added to the resulting suspension. The mixture is stirred at a temperature not exceeding 30 ° C. The yield of 82% wt. This method is the closest to the proposed solution and is selected as a prototype. However, the disadvantage of this method is the low yield of 2-chloro-4-nitrophenol.

The technical challenge is to create a method that provides a higher yield of 2-chloro-4-nitrophenol.

This problem is solved in that the treatment of 4-nitrophenol is carried out with sodium hypochloride in hydrochloric acid at a temperature of 0 ° C.

Example 1: 25 g (0.18 mol) of 4-nitrophenol are mixed with 200 ml of hydrochloric acid (concentration of 35-38% wt.). An equivalent amount (0.18 mol) of sodium hypochloride was added to the resulting mixture and stirred at 0 ° C. The precipitated 2-chloro-4-nitrophenol is filtered off and dried. The output, counting on 4-nitrophenol, is 98.0% wt.

Example 2: 25 g (0.18 mol) of 4-nitrophenol are mixed with 200 ml of hydrochloric acid (concentration of 35-38% wt.). An equivalent amount (0.18 mol) of sodium hypochloride was added to the resulting mixture and stirred at a temperature of + 5 ° C. The precipitated precipitate of 2-chloro-4-nitrophenol is filtered off and dried. The output, counting on 4-nitrophenol, is equal to 90.5% wt. A decrease in the yield of 4-nitrophenol is associated with the formation of by-products, in particular 2,6-dichloro-4-nitrophenol.

Example 3: In the conditions of experience No. 1 and No. 2, the mixture is stirred at a temperature of -5 ° C. Yield 85.0% wt. The decrease in yield is explained by a low reaction rate and incomplete conversion.

The technical advantage is that the treatment of 4-nitrophenol is carried out with sodium hypochloride in hydrochloric acid at a temperature of 0 ° C. Under these conditions, the yield of 2-chloro-4-nitrophenol 98% wt.

Claims (1)

A method of obtaining 2-chloro-4-nitrophenol by treating 4-nitrophenol in hydrochloric acid, characterized in that the processing of 4-nitrophenol is carried out with sodium hypochloride in hydrochloric acid at a temperature of 0 ° C.