CS264698B1 - 2-aminophenol-4- (N, 3'-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,3-carboxyphenyl)sulfonamide and a method for its preparation. The method for preparing 2-aminophenol-4-(N,3-carboxyphenyl)sulfonamide of the formula consists in reducing 2-nitrophenol-4-(N,3-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 90 to 100 °C. I

Description

The present invention relates to 2-aminophenyl-4- (N, 3-carboxyphenyl) sulfonamide and to a process for its preparation.

Metal-complex azo dyes are used for dyeing wool and polyamide, wherein the active component is a 4-amide or 2-aminophenol-4-N-methylsulfonainide active ingredient.

A 2-aminophenol-4- (N, 3-carboxyphenyl) sulfonamide compound having similar uses has now been prepared.

A process for preparing 2-aminophenol-4- (N, 3-carboxyphenyl) sulfonamide of Formula 1

The process of claim 2 wherein the aqueous medium is to reduce 2-nitrophenol-4- (N, 3-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 90-100 ° C.

The resulting mixture of the amino compound slurry and the 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.

CS 264 698 Bl

The conversion process is not accompanied by side reactions. After isolation, the compound of formula I is obtained having a melting point of 253-255 ° C. Diazotization and subsequent coupling titration of this compound confirmed the presence of an aromatically bound amine and determined the relative molar mass of 308.

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

Example

To 60 ml of water, 40 g of iron filings are added while stirring, heated to 80 ° C and 4 ml of hydrochloric acid with a concentration of c (HCl) = 9 mol / l are slowly added. The reaction mixture was heated to 85-90 ° C and allowed to stir at this temperature for 30 minutes

The temperature is then adjusted to 95-100 ° C and slowly added over 4.5 hours with 33.8 g of 100% 2-nitrophenol-4- (N, 3-carboxyphenyl) sulfonamide (0.1 mol). After dosing, the mixture did not count for 100 hours at 100 ° C.

After the reduction is complete, the suspension is taken up in solution with sodium hydroxide c (NaOH) = 10 mol / l and possible dilution 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 acidic reaction of the filtrates was lost.

26 g of the product of formula 1 with the above m.p.

Claims (2)

SUBJECT OF THE INVENTION 1,2-Aminophenyl-4- (N, 3-carboxyphenyl) sulfonamide of Formula I 2. A process for the preparation of 2-aminophenol-4- (N, 3-carboxyphenyl) sulfonamide of the formula I according to claim 1, characterized in that 2-nitrophenol-4- (N, 3-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 90 to 100 ° C.