Development of new methods for the synthesis of five-, six-and seven-membered heterocyclic compounds

Karadeniz, Eda
Synthesis of heterocyclic compounds has become an important area among organic chemists since they occupy a unique position in the design and synthesis of novel biologically active agents that exhibit noteworthy medicinal activities. In this regard, N-propargylic β-enaminones have been recognized as valuable substrates in synthesis because they afford a variety of heterocyclic compounds upon treatment with proper reagents. In this study, new reactivity patterns of N-propargylic β-enaminones were investigated in order to synthesize different heterocyclic compounds. Accordingly, in the first part of study, 5-iodopyridines were prepared by electrophilic cyclization of N-propargylic β-enaminones, and then their Suzuki-Miyaura coupling reaction with boronic acids were investigated to afford 5-aryl-substituted pyridines. Secondly, a facile one-pot method for the synthesis of 2-ferrocenylpyridines has been established. The reaction of α,β-alkynic ketones with propargylamine produced N-propargylic β-enaminones in situ, which, in the presence of copper(I) chloride, have underwent electrophilic cyclization to furnish 2-ferrocenylpyridine derivatives. Thirdly, an efficient method for the synthesis of spiro-2H-pyrroles has been developed. When reacted with 1-ethynylcyclohexylamine, α,β-alkynic ketones produced cyclohexane-embedded N-propargylic β-enaminones, which, upon treatment with cesium carbonate, yielded spiro-2H-pyrrole derivatives via nucleophilic cyclization. In addition, cyclohexane-embedded N-propargylic β-enaminones were further functionalized with aryl iodides. Subsequently, when these arylated β-enaminones were exposed to cesium carbonate mediated nucleophilic cyclization, they produced spiro-2H-pyrroles with two carbonyl groups via further benzylic C-H oxidation. In the last part, a different approach have been employed for the synthesis of spiro-1,4-oxazepines. Upon treatment with zinc iodide and silver hexafluoroantimonate, cyclohexane-embedded N-propargylic β-enaminones produced spiro-1,4-oxazepines.


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Recently, pyrroles, pyridines, 1,4-oxazepines and 1,4-thiazepines have emerged as valuable compounds in the design and synthesis of novel biologically active agents that display prominent medicinal activities. Therefore, development of new efficient methods for their synthesis is highly desired since they can furnish molecules with pronounced or distinct biological activities. Recently, cyclization of functionally substituted alkynes has been recognized as a valuable tool to synthesize a variety of importan...
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Heterocyclic compounds are a momentous area of synthetic organic chemistry because of their existence in bioactive molecules. Pyrroles, which are one of the most important classes of heterocyclic compounds, have great importance in pharmaceutical chemistry due to their biological activities. Having these characteristics makes them drawn attention of most chemists to develop new methodologies for the synthesis of pyrroles. Recently, the cyclization of Npropargylic β-enaminones has been used for the synthesis...
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Synthesizing nitrogen containing heterocyclic compounds is one of the leading research areas throughout the organic chemistry due to their significant activities on biological systems. Among the various biologically active molecules, indole derivatives are of prime importance on the grounds of their proven clinical roles. Objective of this study is to synthesize new indole derivatives those may contribute treatment of several diseases like their analogues via a recently developed synthetic methodology. Besi...
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Citation Formats
E. Karadeniz, “Development of new methods for the synthesis of five-, six-and seven-membered heterocyclic compounds,” Thesis (Ph.D.) -- Graduate School of Natural and Applied Sciences. Chemistry., Middle East Technical University, 2019.