SU396339A1 - METHOD OF OBTAINING 3,7-DIAMINO-! 0-ACETYLPENTIAZINE - Google Patents

Description

The invention relates to a process for the preparation of a new fentiazle derivative, which can be used in the synthesis of biologically active substances.

In the literature, there is a known method for the preparation of 3,7-diam1 -nofenthiazine carboxylic acid or its salts by reducing the S-oxide of 3,7-dinitrophenthiazinecarboxylic acid or its salt, hydrogen hydrogen, in the presence of a catalyst.

However, the resulting target product is unstable and oxidized in air: to the corresponding diaminophenthionium carboxylic acid or its salt.

Using the known reduction reaction of nitro compounds, a derivative of 3,7-diaminophenthiazine was obtained, which, unlike the known derivatives of diaminophenthiazine, is stable and can be used in the transformation of amino groups without fear of forming derivatives of thionin as dyes.

The proposed removal of 3,7-diamino-U-acetylfenthiazine is that 3,7-dinitrophenthiazine is acetylized, for example with acetic anhydride, in the presence of pyridine at boiling. The resulting ory of 3,7-dinitro-10-acetylfenthiazine is preferably reduced by hydrazine hydrate in the presence of a nickel catalyst with

2

50 ° C in a stream of nitrogen. The product obtained is recovered in a known manner in free form or as a salt.

with the highest yield (90%), 3,7 - diamino-10-acetylfenthiazine dihydrochloride is obtained.

However, it is possible to obtain salts with other acids, for example, with acetic acid, oxalic acid, maleic acid.

Example 1. 10-acet1-3,7-dinitrophenthiazine.

15 g of 3,7-dinitrofentnazine, 75 l of "l of acetic anhydride, n 60 ml of inridine are boiled for 6 hours. The warm reaction solution is carefully poured into the ice-cold water by moving and the precipitate formed is filtered off. 15 g (88%) of the substance are obtained. Recrystallized from acetone, it has m. Il. 221 - 223 ° C. The crystals in the form of light brown leaves are readily soluble in alcohol, dichloromethane, chloroform, toluene.

Found %: N 12.51; 12.40; S 9.61; 9.82.

CuHsNsOsS.

Calculated,%: N 12,68; S 9.68.

Example 2. Dichlorohydrate 3,7-diamino-10 acetylfeniazpna.

To 9.9 g (0.03 mol} of 3,7-dinitro-10-acetylfenthiazine n 12 g of a wet-nickel catalyst in 200 ml of alcohol by passing nitrogen and enhanced stirring during

For 30 minutes, Iribagol is dripped with 9 g (0.18. Iol) hydrazine hydrate, (maintaining the temperature no higher than 50 ° C. After the addition of hydrazine GNhydrate is added, the reaction mixture is stirred under the same conditions for another 2 hours until the starting material is dissolved. Then, the reaction solution is filtered from the catalyst into a scoop with siirt nl and saturated ether with a calculated amount of hydrogen chloride necessary for the formation of diamino-10-acetylfenthiazine dichlorohydrate. At the same time, the reaction solution should be kept as small as possible in light. the dichlorohydrate in alcohol is cooled, the precipitated precipitate is separated and washed with ether to obtain 9.3 g (90%) of the substance

216--220 ° C

light blue color, so pl.

(alcohol), readily soluble in water, worse in hot alcohol.

Found,%: C1 20.55; 20.09; S 9.31; 9.34.

С, 4П, зНзО5.2ПС1.

Calculated,%; C1 20.63; S 9,28.

Subject invention

A process for the preparation of 3,7-diamino-0-acetylfenthiazine, characterized in that 3,7-dinitropheniazine 1 removes acetylation, for example, with acetic anhydride, the resulting 3,7-dinitro-10-acetylfenthiazine is reduced, for example by hydrazine hydrate in the presence of a nickel catalyst, with the subsequent isolation of the products in the freeNOL1 form or in the form of salts by known methods.