CS265725B1 - 2 nitrochlorobenzene-4- (N, 2'-carboxyphenyl) sulfonamide and process for its preparation - Google Patents

Abstract

The solution falls into the field of chemistry of organic dyes and preparations for moth protection. The aim of the solution is the compound 2-nitrochlorobenzene-4-(1, 2 '-carboxyphenyl)- sulfonamide and a method for its preparation._The method for preparing 2-nitrochlorobenzene-4-(N, 2 -carboxyphenyl) sulfonamide of formula I consists in reacting a water-soluble salt of anthranilic acid in an amount of 1 to 1.4 mol with 2-nitrochlorobenzene-4-sulfonyl chloride, preferably 1.3 mol of anthranilic acid per 3 mol of sulfonyl chloride, at a pH of 2 to 9, preferably pH 5 to 7

Description

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

The compound 2-nitro] orbenzene-4- (N, 2'-carboxyphenyl) sulfonaroid has been prepared, which can be used for further syntheses, in the field of organic dye chemistry or in the field of preparation of dyes. <· Ιι | i i ml Γ IV. ΰ.

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

Cl (I) is characterized in that the water-soluble anthranilic acid salt is reacted in an amount of 1 to 1.4 moles with 2-nitroblo-benzene-4-sulfonyl chloride, preferably 1.3 moles of anthranilic acid per 1 mol of sulfonyl chloride , 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 control pill meter with sodium hydroxide influx blocking or working in a suitable buffer - e.g. sodium bicarbonate.

The mole ratio between the reacting components influences the yield of the synthesis. With an equimolar ratio of anthranilic acid and 2-nitrochlorobenzene-4-sulfonyl chloride, a yield of 85% of theory (calculated on sulfonyl chloride) is achieved. If the molar ratio is increased to 1.3 moles of anthranilic acid per mole of sulfonyl chloride, the synthesis yield will increase to 92% of theory to the sulfonyl chloride. The anthranilic acid can then be separated from the mother liquors after isolation of the compound of formula I by acidification to pH 3.8 to 4.2 and subsequent filtration. The anthranilic acid thus obtained is returned to the synthesis. In this way, the use of primary raw materials is increased and the waste water ecology is improved.

The compound of formula (I) obtained has a melting point of 203 DEG-206 DEG C., its titration with sodium hydroxide in aqueous medium to 1 to 2 degrees using a potentiometric indication, confirms the presence of the carboxyl and amide groups, and calculates a relative molar mass of 356.5.

Embodiments of the invention are illustrated by the examples.

Example 1

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

After a few hours of reaction, the reaction mixture was heated to 50-60 ° C and acidified to pH 1 with hydrochloric acid (c / HCl) = 9 mol / L 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. 30.3 g of 100% of the compound of formula I are obtained, m.p. 203 DEG-206 DEG.

EXAMPLE 2 13.9 g of 100% anthranilic acid are suspended in 100 ml of water and dissolved by the addition of 12.5 g of sodium lithium carbonate. Directly mix effectively and at temperatures up to. 50 ° C and pH 8 starts to dispense 25.6 g of 100% 2-nitrochlorobenzene-4-sulforiyl chloride (o.I mel i. Heli.m <1 <U env. The feed rate of 1 tonne of chloride can be controlled with respect to the foaming intensity of the reaction mixture.

After a few hours of reaction, the reaction mixture was heated to 50-60 ° C and acidified to pH 11 with hydrochloric acid with stirring.

The solid of formula I is filtered off and the filter cake is washed. warm water to the loss of acidic reaction of the filtrates. Yield: 30.4 g (100%) of Formula 1.

Example 3

18.1 g of 100% anthranilic acid (1.3 mol) was suspended in water (100 ml) and dissolved by addition of sodium hydroxide to pH 7.5. 25.6 g of 100% 2-trifluorobenzene-4-sulfonyl chloride (0.1 mol) was added to the solution with uniform stirring at 20-50 ° C. During the post-reaction, the pH is maintained at 5-7 by blinding with sodium hydroxide.

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

The solid of formula I is filtered off and the filter cake is washed with warm water until the filtrate is neutral.

The collected filtrates were acidified to pH 4 with hydrochloric acid, the anthranilic acid suspension was filtered, and the filter cake was washed with water until the filtrate was neutralized.

The obtained anthranilic acid is returned to the reaction. 32.6 g of 100% of the compound of formula 1 are obtained.

Claims (2)

1. 2-Nitrochlorobenzene-4- (N, 2'-carboxyphenyl) sulfonamide of formula I (I) · 2. A process for the preparation of 2-nitrochlorobenzene-4- (N, 2'-carboxyphenyl) sulfonamide of formula (I) according to claim 1, characterized in that the water-soluble anthranilic acid salt is reacted in an amount of 1 to 1.4 mol with 2-nitrochlorobenzene-4. sulfonyl chloride, preferably 1.3 moles of anthranilic acid per mole of sulfonyl chloride, at a pH of 2 to 9, preferably a pH of 5 to 7.