Multicomponent synthesis of hetaryl substituted hydroquinolinone and hydroquinazolinone compounds

Heterocyclic compounds and their derivatives constitute a branch of organic chemistry developing quite rapidly and becoming more important day by day. Heterocyclic compounds containing the atoms of elements such as nitrogen, sulfur and oxygen as the ring members are commonly used in various fields of industry as analytical reagents, ligands, dyestuffs, pharmaceutical substances and bioindicators.According to the literature surveys made, this study is aimed at the synthesis of some new tetrahydroquinolinone and tetrahydroquinazolinone derivatives containing substituted hetaryl groups known to have biological activity, which may therefore be potentially useful.In this study, quinolinone and quinazolinone system derivatives were synthesized via one-pot three-component reactions. These reactions, which are carried out using the method of multicomponent reactions (MCRs), proceed as domino processes, making them easier to occur than the conventional multistep organic reactions. This method enables new organic molecules to be synthesized in a single step, using a minimal amount of time and number of trials.Our study was composed of two steps: In the first step, the heteroaromatic carboxaldehydes to be used as substrates in our reactions were prepared by the oxidation of 2-methylquinoline, 2,6-dimethylquinoline, 2,4,6-trimethylquinoline and 2,4,7-trimethylquinoline by selenium dioxide, which is a mild oxidant. The other substrates of the study, namely pyridine-2-carboxaldehyde and 6-methylpyridine-2-carboxaldehyde were commercially obtained.In the second step which is the main goal of this study, compounds of 12 new hydroquinolinone and 6 new hydroquinazolinone derivatives having quinolinyl or pyridinyl ring as the substituent were synthesized by the condensation of each of these aldehydes (quinoline-2-carbaldehyde, 6-methylquinoline-2-carbaldehyde, 4,6-dimethylquinoline-2-carbaldehyde, 4,7-dimethylquinoline-2-carbaldehyde, pyridine-2-carbaldehyde and 6-methylpyridine-2-carbaldehyde) with dimedone and an appropriate amine in absolute ethyl alcohol, by means of the one-pot multicomponent reaction.Structures of the all obtained compounds, which were produced almost in high yields, were clarified by using infrared, nuclear magnetic resonance and mass spectroscopical data.