CS264797B1 - 2-aminophel-4- (N, 2'-carboxyphenyl) sulfonamide; - Google Patents

Abstract

The solution falls into the field of organic dye chemistry. The aim of the solution is the compound 2- -aminophenol-4-(N,2'-carboxyphenyl)sulfonamide and a method for its preparation. The method for preparing 2- -aminophenol-4-(N,2'-carboxyphenyl)sulfonamide of the formula I OH,nh2 COOH (i) Šo2 —NH—00 consists in reducing 2-nitrophenol-4-(N,2 - -carboxyphenyl)sulfonamide in an aqueous medium with a mixture of iron and hydrochloric acid or a mixture of iron and ferrous salts of hydrochloric or sulfuric acid at a temperature of 95 to 100 °C.

Description

The present invention relates to 2-aminophenol-4- (N, 2'-carboxyphenyl) sulfonamide and to a process for its preparation.

Metal-complex azo dyes are used for dyeing wool and polyamide, wherein 2-aminophenol-4-sulfonamide or 2-aminophenol-4-N-methylsulfonamide is used as the active component.

The compound 2-aminophenol-4- (N, 2'-carboxyphenyl) sulfonamide has now been prepared for similar use.

Process for the preparation of 2-aminophenol-4- (N, 2'-carboxyphenyl) sulfonamide of formula I

OH

The process of claim 2 wherein the aqueous medium is to reduce 2-nitrophenol-4- (N, 2'-carboxyphenyl) sulfonamide with a mixture of iron and hydrochloric acid or a mixture of iron and ferrous salts of hydrochloric or sulfuric acid at a temperature of 95-100 ° C.

The resulting mixture of the amino compound slurry and reducing products (reducing sludge) was separated by converting the amino compound into alkaline solution with sodium hydroxide and isolating the solid suspension by filtration. The compound of formula I is precipitated from the solution by acidification with a suitable acid, e.g. hydrochloric acid.

The conversion process is not accompanied by chemical side reactions. After isolation, a practically pure compound of formula I is obtained with a melting point of 213 DEG-215 DEG C. in a yield of 90% of theory. Diazotization and subsequent coupling titration of this compound confirmed the presence of the aromatically bound amine and determined the relative molar mass 308.

An embodiment of the invention is illustrated by the following example.

Example

To 60 ml of water, 40 g of iron filings and 4 ml of hydrochloric acid having a concentration of c (HCl) = 9 mol / l are added while stirring. The reaction mixture was heated to 90-95 ° C and allowed to stir at this temperature for 30 minutes.

The temperature is then adjusted to 95-100 ° C and slowly added 33.8 g of 100% 2-nitrophenol-4- (N, 2'-carboxyphenyl) sulfonamide (0.1 mol). After dosing, the mixture was allowed to react for 5 to 8 hours at 100 ° C.

Upon completion of the reduction, the mixture is brought into solution with sodium hydroxide c (NaOH) = 10 mol / l, optionally diluted with water. After alkalization, the solution has a final pH of 11 to 12.5.

The solution is heated to 100 ° C, stirred briefly and the reducing sludges are separated by filtration.

The filtrate is cooled to 10-20 ° C, acidified slowly with hydrochloric acid and the product isolated by filtration. The filter cake was washed with water until the filtrates lost acidity.

27.7 g of the product of formula I of m.p. Mp 213-215 ° C.

Claims (2)

SUBJECT OF THE INVENTION A 2-aminophenol-4- (N, 2-carboxyphenyl) sulfonamide of formula I OH ά nh ₂ COOH (I) SO ₂ —NH 2. A process for the preparation of 2-aminophenol-4- (N, 2-carboxyphenyl) sulfonamide of the formula I according to claim 1, characterized in that 2-nitrophenol-4- (N, 2-carboxyphenyl) sulfonamide is reduced in an aqueous medium by a mixture of iron and hydrochloric acid or a mixture of iron and ferrous salts of hydrochloric or sulfuric acid at a temperature of 95 to 100 ° C.