SU85031A1 - The method of obtaining benzthiazolyl- (2) -hydrazine and its substituted benzene - Google Patents

Description

Benzthia; yulyl- (2) -hydrazine and some of its substituted ones are used to synthesize pyrazolone- (5) derivatives with a benzthiazole residue in the first position and some other heterocyclic compounds, are the components for color formation. IrodkujaMii for seysibilnziruop1, their dyes.

It is known that benzthiazolyl- (2) 1-idrazine is obtained by the action of guide-azinghydrate on 2-chloro, 2-sulfo- and 2-hydroxybenzene nazols, but these benzthiazole derivatives are not readily available.

A novel method for obtaining benzthiazolyl- (2) -hydrazine and eio substituted in the benzene core is proposed.

It was found that benznazolyl- (2) hydrazine and its substituted in the benzene core of the general formula:

S

Nhh.,

where RijRj H.COOH or .ipyrHe for .lipdayupd, s groups, can be obtained in a pure state and in good yields (to) under the action of aqueous solutions of hydrazineide1) ata on the corresponding 2-aminobenzenenazo, which are more accessible combined many compared with 2-chloro 1-, 2-sulfonic and 2-hydroxy 113 thiazoles,

Example 1. A mixture of 7.5 g of 2-aminobenzthiazole and 60 ml of a 35% solution of hydrazine hydrate, prepared by heat of 20 g of hydraziphydrate and 40 ml of water, heated from a round bottom flask to a reflux condenser in an oil bath at 120 125 (in oil ) within 10-12 hours. There is a vigorous release of ammonia. You, while cooling the reaction mass, filter the precipitate, rinse with water and dry. The yield of benzthiazolyl {2) - -idrazine is 2.8-3.0 g or 34-Zb, from theoretically possible Io. Brilliant, colorless needles with a t. P. 180-182. After recrystallization from ethyl alcohol, m.p. 183-184.

Example 2. 10 g of 2-amybenzithiazole-6-carboxylic acidic acid, 101y is heated for 9-10 hours. with a solution of 7.5 lg of hydrazine hydrate in 25 ml of water per weight, 1X1 bath at 120–122 (in oil). Cool the reaction mixture is stirred with 150 l / l 15 / and hydrochloric acid hydrochloric acid is filtered off and rinsed with water, / (l of purification, the product is dissolved in 10 / one soda solution, separated by acidification with hydrochloric acid, filtered, They are washed cold with a node and stirred at ordinary temperature with 40 ml of 10–15% sodium acetate solution. The precipitate is filtered, washed with water and dried. The yield of 6-carboxybenzothiazolyl- (2) -hydrazine is 9 g or 85.7 / 6 from theoretically possible. Almost colorless crystals with a melting point above 300.

Example 3. 11.9 g of 2-aminobenzthiazol-5, 7-dicarboxylic acid are introduced into 50 ml of 50% aqueous hydrazine hydrate and the mixture is heated for 15 hours. on an oil bath 125 - 130. The reaction mass is poured into 200 ml of concentrated hydrochloric acid. After 1 hour, the precipitate is filtered off, washed with water and precipitated

from lOVo-Horo soda hydrochloric acid solution. The yield of 5,7-dicarboxybenzthiazolyl- (2) -hydrazine is 7-7.4 g or 55-60% of the theoretically possible. Light cream crista. 1 face with the so-called nl. above 300

Example 4. A mixture of 11.9 g of 2-aminobenzthiazole-5,6- dicarboxylic acid and solution) and 7.5 ml of hydrazine hydrate in 25 L1L of water is heated for 6 hours. in an oil bath at 120-122 after which the reaction

Maccv poured into

concentrated hydrochloric acid. The precipitate was filtered off, washed with water and dried. The yield of 5,6-dicarboxybenzthiazolyl (2) -hydrazine is 10.5 g or 83 / o of the theoretically possible. Slightly yellowish powder with so pl. above 600 °.

Subject invention

The method of producing benzthiazol. A (2) -hydrazine and its substituted in the benzene core, o tl and h and s; and by the fact that 2-aminobenzene, or its corresponding derivatives are treated with an aqueous solution of hydrazine hydrate at elevated temperatures.