SU1325049A1 - Method of producing 3-amino-1,2-benzisothiazole - Google Patents

Abstract

The invention relates to heterocyclic compounds, in particular to the preparation of 3-amino-1,2-benzisothiazole (AB), which is used in the synthesis of biologically active compounds. The increase in the yield of AB and the simplification of the process is achieved by using other source reagents. Synthesis of ABs is carried out from 3-chloro-1,2-benzisothiazole and dry gaseous NKj in formamide at 130-160 C. The yield of AB is increased 3 times in comparison with the known method. (L

Description

This invention relates to a process for the preparation of 3-amnno-1,2-benzioothiazole, which is used in the synthesis of biologically active compounds.

The aim of the invention is to increase the yield of the target product and simplify the process technology.

The goal is achieved by the interaction of 3-chloro-1,2-benzisothiazole with dry ammonia gas in a formamid-medium at 130-160 C.

Example I. 17 g (0.1 mol) of 3-chloro-1,2-benzisothiazole are dissolved in 150 ml of formamide, the solution is heated up to and a current of dry ammonia (1 vial per 1 minute) is passed into it for 5 hours. reactionary Pour is poured on ice. The separated white fibrous precipitate is filtered and dried in air. The product — small white needles — is dissolved in hot water, alcohol, ether, and acetone, m.p. 115 ° C, yield 12.5 g (83%

Found,%: C 56.11; H 4.12; N. 18.54; S 21.21

Calculated,%: C 56.00; H 4.00; N 18.67; S 21.33.

Approx. 2. 17 g (0.1 mol) of 3-chloro-1,2-benzisothiaeol is dissolved in 150 ml of formamide, the solution is heated to l6d ° C and a flow of dry ammonia (1 vial per minute) is passed into it 3 hours. Then reactivity 3 times, and also simplify the process technology.

Claims (1)

Invention Formula The mixture is poured onto ice, which isolates, in a manner known per se, the oily white fibrous precipitate is filtered off and dried in air. The product — small white needles — is dissolved in hot water, alcohol, ether, and acetone, m.p. П5 ° С, you- About 13.1 g (87%). Found,%: C 55.98; H 4.12; N 18.65; S 20.97 Calculated,%: C 56.00; H 4.00; N 18.67; S 21.33. PRI me R 3. 8.5 g (0.05 mol) of 3-chloro-1,2-benzisothiazole is dissolved in 75 ml of formamide, the solution is heated to 120 ° C and a flow of dry ammonia is passed into it for 6 hours. . The method of obtaining 3-amino-1,2-benzisothiazole using a derivative of 1, 2-benzisothiazole, in order to increase the yield of the target product I h and simplify the process technology, as a derivative of 1,2-benzisothiazole, Z-chloro-1,2-benz-isothiazol is used and it is subjected to interaction with dry gaseous ammonia in a formamide medium at 130-1.60 C. Then the reaction mixture is digged on ice. The white precipitated white precipitate is filtered and dried in air. The product — small needles — is dissolved in hot water, alcohol, ether, and acetone, m.p. yield 3.0 g (20%). Found,%: With 56.41; H 4.25; N 18.43; S 21,67 Calculated,%: C 56.00; H 4.00; N 18.67; S 21.33 Example4. 25.5 g (0.15 mol) of 3-chloro-1,2-benzisothiazole are dissolved in 225 ml of formamide, the solution is heated to and a current of dry ammonia is passed into it for 2 hours. Then the reaction mixture is poured onto ice. The separated white fibrous precipitate is filtered and dried in air. The product is small rods contaminated with osmol, dissolved in hot water, alcohol, ether and acetone, m.p. 110 ° C, yield 4.3 g (19%). Found,%: C 57.13; H 5.01; N 17.07; S 19.15. thirty Calculated,%: C 50.00; H 4.00; N 18.67; S 21.33. Thus, the implementation of the proposed method in the temperature range of 130-160 ° C allows to obtain the target product with an output that exceeds 3 times, and also simplifies the process technology. Invention Formula output by a known method of 35 way out of the known method of the The method of obtaining 3-amino-1,2-benzisothiazole using a derivative of 1, 2-benzisothiazole, in order to increase the yield of the target product I h and simplify the process technology, as a derivative of 1,2-benzisothiazole, Z-chloro-1,2-benz-isothiazol is used and it is subjected to interaction with dry gaseous ammonia in a formamide medium at 130-1.60 C.