Vodolazhenko M. One-pot sequential interaction of 1,3-dicarbonyl CH-acids with N,N-dimethylformamide dimethylacetal and active methylene nitriles

The thesis is dedicated to the development of new effective synthetic methods for increasing of molecular diversity of heterocycles based on one-pot sequential interactions, polyfunctional compounds, non-classical methods for activation of chemical processes and principles of green chemistry on example of an reaction between 1,3-dicarbonyl CH-acids, DMFDMA and methyleneactive nitriles. Hydrolysis of intermediate 4-cyanobuta-1,3-dienolates in an acidic medium results in the selective formation of 2-pyrone-3-carboxamide derivatives. This allowed us to develop a one-pot three step method and synthesize a wide library of such compounds. It was shown that activation of the amide group of 4-cyanobuta-1,3-dienolates takes place in the aqueous medium and leads to the selective formation of 2-pyridone-3-carbonitrile derivatives. Kinetic studies were also carried out, and a possible mechanism for this transformation has been proposed. When 2-cyanomethylbenzimidazole is used as the active methylene nitrile with cyclic CH-acids and DMFDMA, 4-oxo-1,2,3,4-tetrahydrobenzo[4,5]imidazo[1,2-a]quinolin-6-yl cyanides are selectively formed, and 4-cyanobenzo[4,5]imidazo[1,2-a]pyridine-2-carboxylates (piperidine in microwave heating) or 4-cyanobenzo[4,5]imidazo[1,2-a]-pyridin-1-olates (catalyzed by sodium methylate at room temperature) which gave 1 hydroxybenzo[4,5]imidazo[1,2-a]pyridine-4-carbonitriles after acid treatment, are formed in the reaction with acyclic β-ketoesters. Using quantum chemical calculations, it has been shown that tautomeric equilibrium and stability of 2-iminocoumarin-3-carboxamides and 2-imino-5-oxo-5,6,7,8-tetrahydro-2H-chromene-3-carboxamides have similar trends, which indicate a similar behavior of these compounds in chemical transformations. Based on experimental, literary and calculations data, the mechanisms of the studied transformations were proposed.