CS265432B1 - 2-nitrochlorobenzene-4- (N, 3'-carboxyphenyl) sulfonamide; - Google Patents

Abstract

The solution falls into the field of chemistry of organic dyes and pigments and preparations for moth protection. The aim of the solution is the compound '2-nitrochlorobenzene-4-(N,3'-carboxyphenyl)sulfonamide. and a method of its preparation. The method of preparation of 2-nitrochlorobenzene-4-(N,3'-carboxyphenyl, sulfonamide of formula I consists in reacting a water-soluble salt of 3-aminobenzoic acid in an aqueous medium with 2-nitrochlorobenzene-4-sulfonyl chloride at pH 2 to 9, preferably pH 5 to 7. The preferred pH range is maintained within a specified range during synthesis by a regulating pH meter with blocking the sodium hydroxide inflow or by working in a suitable buffer environment - e.g. bicarbonate.

Description

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

The compound 2-nitrochlorobenzene-4- (N, 3'-carboxyphenyl) sulfonamide was prepared, which can be used for further syntheses in the field of organic dyes and pigments chemistry or in the preparation of antimoly agents.

A process for the preparation of 2-nitrochlorobenzene-4- (N, 3'-carboxyphenyl) sulfonamide of formula I

The COOH (I) comprises reacting a water-soluble salt of 3-aminobenzoic acid with 2-nitrochlorobenzene-4-sulfonyl chloride in an aqueous medium at a pH of 2 to 9, preferably a pH of 5 to 7.

In the actual synthesis, the preferred pH range is maintained within a specified range by means of an automatic pH-metering control blocking the influx of sodium hydroxide, or working in a suitable buffer - e.g., bicarbonate.

Embodiments of the invention are illustrated by the examples.

Example 1

13.9 g of 100% 3-aminobenzoic acid are suspended in 100 ml of water and dissolved by addition of sodium hydroxide solution to pH 7.5. 25.6 g of 100% 2-nitrochlorobenzene-4-sulfonyl chloride (0.1 mol) are metered into the resulting solution evenly with efficient stirring at 20 to 50 ° C and the resulting acidity is blunted with sodium hydroxide solution c (NaOH) ) = 10 mol / l so that a solution with a pH of 5-7 is continuously formed.

After several hours of reaction, the reaction mixture was heated to 50-60 ° C and acidified with stirring to a pH of 1 with c (HCl) = 9 mol / L hydrochloric acid.

The suspension of the compound of formula I is filtered off and the filter cake is washed with warm water until the acidic reaction of the filtrates is lost. 32 g of 100% of the compound of formula I are obtained, m.p. Mp 252-254 ° C.

Example 2

13.9 g of 100% 3-aminobenzoic acid are suspended in 100 ml of water and dissolved by the addition of 12.5 g of sodium bicarbonate. 25.6 g of 100% 2-nitrochlorobenzene-4-sulfonyl chloride (0.1 mol) are started to be metered in evenly with efficient stirring at 20 to 50 ° C and pH 8. The pH level is maintained at 5-7 during dosing and reaction. The actual rate of sulfonyl chloride dosing must be controlled with respect to the foaming intensity of the reaction mixture.

After several hours of reaction, the reaction mixture was heated to 50-60 ° C and acidified to pH 1 with hydrochloric acid with stirring.

The solid of formula I is filtered off and the filter cake is washed with warm water until the acidic reaction of the filtrates is lost. 31.8 g of 100% of the compound of formula I with the above-mentioned m.p.

Claims (2)

SUBJECT OF THE INVENTION 1. 2-Nitrochlorobenzene-4- (N, 3'-carboxyphenyl) sulfonamide of formula I Cl (I) 2. A process for preparing 2-nitrochlorobenzene-4- (N, 3 ¹ -karboxyfenyl) sulfonamide of formula I according to claim 1, wherein the water soluble salt of 3-aminobenzoic acid is reacted in a water environment therein with 2-nitrochlorobenzene-4-sulfonyl chloride at pH 2 to 9, preferably pH 5 to 7.