The objects - the derivatives of 1,4-dihydropyridine - and pyridinedi-carboxylic acid; purpose - establishment of conformities to the law of flowing of reaction of hydrazinolysis in a 1,4-dihydropyridines (esters Hantzscha) and pyridines, which have two and more after reactionary center; novelty - It is determined, that the presence of alkyls or aryls substituents in 4-position 2,6-dimethyl-pyridine-3,5-dicarboxylic acid diethyl ester creates sterical obstacles for carried out reaction of hy-drazinolysis on ?,?'-carboetoxy groups. The transformation of carboe-toxy groups in the presence of NBS in ?-lactones cycle removes the sterical obstacles and the reaction of hydrazinolysis occurs with the opening of the ?-lactones ring and results in creation of mono- and bis-hydrazides 2,6-bis-hydroxymethyl-pyridine-3,5-dicarboxylic acid. Hy-drazinolysis of 2,6-dimethyl-1,4-dihydro-pyridine-3,5-dicarboxylic acid diethyl ester with various substituents in 4-position (Н, Рh, Me) occurs as a reaction of recyclization accompanied by the opening of the 1,4-dihydropyridines ring and creation of corresponding bis-(5-methyl-3-oxopyrazol-4-yl)-methane's, which have aromatic (ОН - tautomeric) formation. A method of synthesis of previously unknown of 5-hydrazinocarbonyl-2,6-dimethyl-nicotinic acid ethyl ester was devel-oped. Synthesis of several acyl-derivatives and acylhydrazones of 5-hydrazinocarbonyl-2,6-dimethyl-nicotinic acid ethyl ester and bis-hydrazides 2,6-dimethyl-pyridine-3,5-dicarboxylic acid was performed, as well as synthesis of corresponding 1,3,4-oxadiazoles; their reactive capacity in the reaction of hydrazinolysis was researched. Unusual way of the reaction hydrazinolysis 2,6-dimethyl-5-(N'-methylsulfanylthiocarbonyl-hydrazinocarbonyl)-nicotinic acid methyl ester (reaction of Hoggart ) was discovered, which leads to formation of 5-(5-mercapto-[1,3,4]oxadiazol-2-yl)-2,6-dimethyl-nicotinic acid hy-drazide. High fungicide and fungiostatical activities of 5-(N'-dithiocarboxy-hydrazinocarbonyl)-2,6-dimethyl-nicotinic acid methyl ester potassium salt in relation to fungi of Candida family was deter-mined
