SU1766919A1 - Method of n-(5,7-dibromobenzo-2,1,3-thiazolyl-4)-2- (4-chlorophenylsulfon-anido)-5-bromobenzamide synthesis - Google Patents

Abstract

The essence of the invention: product - N-

Description

The invention relates to an improved process for the preparation of (5,7-dibromobenzo-2,1,3-thiadiazolyl-4) -2- (4-chlorophenylsulfonamido) -5-bromobenzamide of the formula

Cl- / SO NHVg

rrV-coNH-fV-Br

LI J / - h

VgXS

with anthelmintic activity, which can be used in the chemical and pharmaceutical industry.

A known method for preparing N- (5,7-dibromobenzo-2,1,3-thiadiazolyl-4) -2- (4-chlorophenylsulfonamido) -5-bromobenzamide. the fact that 4-aminobenzo-2,1,3-thiadiazole is cylated with chlorohydride 2- (4-chlorophenylsulfonamido) -5-bromobenzoic acid hydride, isolated (benzo-2,1,3-thiadiazolyl-4) -2 - (4-chlorophenylsulfonamo-) -5-bromobenzamide is brominated with bromine in a mixture of acetic acid and dimethylformamide at 40-50 ° С 1. The yield of the target product is 52.8%.

The disadvantage of this known method is the low yield of the target product.

The purpose of the invention is to increase the yield of the target product.

The goal is achieved by the method in which 4-aminobenzo-2,1,3-thiadiazose is acylated with 2- (4-chlorophenylsulfensmido) benzoic acid chloride, isolated by M- (benzo-2,1,3-thiadiazolyl-4) -2- (4-chlorophenylsulfonamido) benzamide is brominated with bromine in a mixture of acetic acid and dimethylformamide at 50-60 ° C.

The following examples illustrate the method of the invention.

Example 1

Step 1. Preparation of M- (benzo-2,1,3-thiadiazolyl-4) -2- (4-chlorophenylsulfonamido) benzamide (I).

15.6 g (0.05 mol) of 2- (4-chlorobenzenesulfonamido) benzoic acid and 35 ml of thionyl chloride are heated at boiling for 1 h, the excess of thionyl chloride is distilled off in vacuo to dryness, the residue is dissolved in 120 ml of dichloroethane , 9.1 g (0.06 mol) of 4-aminobenzo-2,1,3-thiadiazolium are added

(L

WITH

: CN

,Yu

YU

i

10 ml of triethylamine, left overnight, Dichloroethane is distilled off to dryness, 100 ml of glacial acetic acid are added to the residue, the residue is filtered off, washed with water, yield 20.3 (91%), pink powder, m.p. . 185-187 ° C (acetone). Found,%: C 50.9; H 3.1; CI 7.9; S 14.3.

C19H13CI403S2

Calculated,%: C, 51.3; H 2.9; CI 8.0; From 14.4.

Step 2. Preparation of M- (5,7-Dibromobenzo-2L, 3-thiadiazolyl-4) -2- (4-chlorophenylsulphonamido) -5-bromobenzamide.

To 4.5 g (0.01 mol) of compound I in a mixture of 15 ml of glacial acetic acid and 5 ml of dimethylformamide are added dropwise with stirring 6.4 g (0.04 mol) of bromine in 6 ml of ice-cold acetic acid at 50-60 ° C.4. At the end of the addition of bromine, the reaction mass is further stirred at this temperature for 30 minutes, the separated precipitate is filtered, washed with acetic acid and water, the yield is 5.9 g (86%), cream-colored powder, m.p. 272-274 ° C (a mixture of acetic acid and dimethylformamide).

Found,%: Br 35.7; C 5.3; N 8.0; S 9,5. С1эНюВгзС1Ы40з52.

Calculated,%; Br 35.2; C 5.2; N 8.2; S 9.4.

The mp of the product obtained and the IR spectrum are identical. and the IR spectrum of the product obtained in a known manner.

The method according to the invention allows to increase the yield of the target product from 52.8 to 78.26%.

Claims (1)

Invention Formula The method of obtaining M- (5,7-dibromobenzo-2,1,3-thiadiazolyl-4) -2- (4-chlorophenylsulfonamido) -5-bromobenzamide of the formula Ct-Q -S02 JHBr rrV-CONH- VBr Vg including the acylation of 4-aminobenzo-2,1,3-thiadiazole to the 2-phenylsulfonamidobenzoic acid chloride acid derivative and bromination of the isolated derivative of N- (5-benzo-2,1,3-thiadiazolyl-4) -2-phenylsulfonamidobenzamide with bromine in an acetic acid mixture dimethylformamide at elevated temperature, characterized in that, in order to increase the yield of the target product, 2- (4-chlorophenylsulfonamide) benzoic acid chloride and 2- (3,3,3) are used as a derivative of 2-phenylsulfonamidobenzoic acid chloride. -taad olil-4) -2- (4-chlorophenyl sulfonamido) benzoic acid bromiru- dissolved at 50-60 ° C.