(-)-[[4-(1,4,5,6-TETRAHYDRO-4-METHYL-6-OXO-3-PYRIDAZINYL)PHEN- -YL]HYDROZONO]PROPANEDINITRILE AND ITS PHARMACEUTICALLY ACCEPTABLE SALTS, PHARMACEUTICAL COMPOSITION BASED ON THEREOF, METHOD OF SYNTHESIS OF INTERMEDIATE COMPOUND AND METHOD OF SYNTHESIS OF END COMPOUND Russian patent published in 1998 - IPC

FIELD: organic chemistry, pharmacy. SUBSTANCE: invention relates to the pure (-)-enantiomer of [[4-(1,4,5,6-tetrahydro-4-methyl-6-oxo-3-py- -ridazinyl)phenyl] hydrozano] propanedinitrile. Invention proposes method of synthesis of an intermediate optically pure (-)-6-(4-aminophenyl)-5-methyl-4,5-dihydropyridazine-3(2H)- -one by treatment of a mixture of parent enantiomers with L-tartaric acid excess, preferably 2-3 equivalents, in propanol, at heating followed by cooling of the obtained solution to the room temperature. Obtained crystalline compound is separated, converted to free base by alkalization, free base is dissolved in dioxane at heating and the obtained solution is cooled to the room temperature. Then obtained mixture is separated for precipitate containing racemic 6-(4-aminophenyl)-5-methyl-4,5-dihydropyridine-3(2H)-one and filtrate containing optically pure (-)-enantiomer of an indicated intermediate compound. For synthesis of (-)-enantiomer of the end compound at optical density above 90% an intermediate (-)-enantiomeric compound synthesized by method indicated above is treated with sodium nitrate and malononitrile. Synthesized compounds and their pharmaceutically acceptable salts are used for preparing pharmaceutical composition showing cardiotonic effect. Composition has an effective dose of indicated enantiomer or its salt in mixture with pharmaceutically acceptable vehicle. EFFECT: improved method of synthesis, enhanced effectiveness of compounds synthesized. 5 cl, 6 ex, 2 tbl, 1 dwg