SU256776A1 - METHOD OF OBTAINING N-ALKYL DERIVATIVES l, 2-DIHYDOPOPASY - Google Patents

Description

The invention relates to the field of obtaining members of a class of heterocyclic compounds that are interesting as intermediates in the synthesis of biological active substances.

A method for the preparation of N-alkyl 1,2-dihydropyrazino- (3,2,1-jk) carbazole derivatives of the general formula

N - A1K

in which R is H, Alk, O-Alk (Alk is an alkyl group).

The method consists in that the derivatives of 1,10 trimethyl-pyrazino- (1,2-a) -indole are simultaneously subjected to alkylation and dehydrogenation by boiling with alcohols in the presence of skeletal nickel, followed by isolation of the target product in a known manner.

Example 1. Preparation of 1,2-dihydro-3-ethylpyrazino- {3, 2,1-jk) -carbazole. 2.1 g (0.01 mol) of 1,10-trimethylenepyrazipo- (1,2-a) -indole, 4 ml of a skeletal nickel suspension in ethanol and 60 ml of ethanol are placed in a flask. The reaction mixture was boiled for 6 hours.

the hot solution is filtered, the catalyst is repeatedly washed with ethyl alcohol, and the filtrate is evaporated in vacuo. The yield of 1,2-dihydro - 3-ethylpyrazino - (3,2,1-jk) - carbazole

2.1 g (91%); T. Il. 109-110 ° С (from alcohol).

Found,%: C 81.48; 81.57; H 6.68; 6.85; N 11.86; 12.07. CienieNo. Calculated,%: C 81.32; H 6.82; N 11.85.

Example 2. Obtaining picrate of 1,2-dihydro-Z-butyl-8-methylpyrazine - (3,2, l-jk) -Kap6azola. In a flask equipped with a Dean-Stark nozzle, 2.2 g (0.01 mol) of 1,10-trimethylene-8-methylpiperazino - (1,2-a) -indole are placed,

4 ml of skeletal nickel suspension in water and 80 ml of n-butyl alcohol. The reaction mixture was treated with cues t G h, the hot solution was filtered, the catalyst was repeatedly washed with n-butyl alcohol, and the filtrate was evaporated

in vak) lme. The remaining oil is dissolved in 30 ml of ethanol and mixed with a solution of 2.9 g (0.01 mol) picric acid in 50 ml of ethanol.

The precipitated crystals are filtered and

washed several times with ether. Get

2.9 g (93.5%) of 1,2-dihydro-3-butyl-8-methyl-pyrazino- (3,2,1-jk) -carbazole picrate; m.p.

160-161 ° C (from acetone).

SozNzNzOt.

Calculated,%: C 59.16; H 4.97; N 13.80.

Example 3. Obtaining 1,2-dihydro-3,8-dimethylpirazino- (3,2, l-jk) -carbazole. 1.1 g (0.005 mol) of 1,10-trimethylene 8-methyl-piperazino- (1,2-a) -indole, 2 ml of skeletal nickel suspension in methanol, 30 ml of methanol and 30 ml of xylene are placed in a flask. The reaction mixture is boiled for 4 hours, then methyl alcohol is distilled off until the temperature in the reaction mass reaches 130-140 ° C and continue to boil for another 3 hours. The hot solution is filtered, the catalyst is washed with xylene, the filtrate is evaporated in vacuo. The yield of 1,2-dihydro-3,8-dimethylpyrazino- (3,2,1jk) carcazole 1.1 g (95.6%); m.p. 134-135 ° C (from acetone).

Subject invention

The method of obtaining the N-alkyl derivatives of l, 2-dihydropyrazino- (3,2, l-jk) -carbazole of the general formula

/ V

N-alk

wherein R-H, Alk, O-Alk, Alk is an alkyl group, characterized in that the 1,10-trimethylenepyrazino- (1,2-a) -indole derivatives are boiled with alcohols in the presence of skeletal nickel, followed by isolation of the target product in a known manner.