Kimya

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Browsing Kimya by Author "Agopcan, Sesil."

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    Modeling cycloaddition reactions
    (Thesis (M.S.) - Bogazici University. Institute for Graduate Studies in Science and Engineering, 2011., 2011.) Agopcan, Sesil.; Aviyente, Viktorya.
    In this study, the selectivities in two types of cycloaddition reactions, namely Diels- Alder and 1,3-dipolar cycloadditions are investigated. In the first part, the diastereoselectivity in the hydrogen bonding assisted Diels-Alder reactions have been investigated by using different chiral dienes with achiral dienophiles with density functional methods. C9-substituted chiral anthracene templates are used to find out the role of chiral substituents and H-bonding on the product distribution ratio. As a the second study in this part, the π-facial selectivity induced by the presence of a chiral auxiliary in 1,4-substituted butadienes has been considered in order to rationalize the role of the chiral substituent on the stereoselectivity. In the second part, the conjugate addition/intramolecular nitrone dipolar cycloaddition is investigated with the use of density functional theory. The 1,3-dipolar intramolecular cycloaddition reaction of nitrone is analyzed in details. The most stable and energetically favored mechanism is searched for the interconversion of 6,5,5-tricyclic products to the 6,6,5-tricyclic structure which is the core intermediate to synthesize histrionicotoxins.
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    Synthesis, evlatuation of functional methacrylates and a computational approach to the reactions of molecules with biological potential
    (Thesis (Ph.D.) - Bogazici University. Institute for Graduate Studies in Science and Engineering, 2017., 2017.) Agopcan, Sesil.; Avcı, Duygu.; Aviyente, Viktorya.
    In this dissertation, experimental and computational methods are used to in vestigate the molecules which are biologically active and have potential in pharma ceutical field. This study sheds light on the synthesis procedures of methacrylate based monomers, characterization of the synthesized materials, and also detection of reaction mechanisms, calculations of thermodynamic properties in several reactions. In the first three chapters, several methacrylate monomers were investigated which have various biomedical applications. The synthesis and photoinitiating abilities of six novel methacrylate-based monomeric photoinitiators (MPIs) has been carried out. In order to make useful predictions on the reactivities of methacrylates, a relationship between reactivities of 21 methacrylates in free radical polymerization and their chem ical structures were built by a non-linear expression. Finally, methacrylates were used to prepare PEG-based carboxylic-acid functionalized monomers which were incorpo rated into hydrogel scaffolds for biomedical applications. In the last three chapters, the reactions of biologically active molecules were analyzed by computational tools. The exo-stereoselectivity of norbornene in the synthesis of thiazolidine derivatives which have diverse biological potential, are clarified by means of Density Functional Theory (DFT). Another biologically active molecule, diclofenac that is used as a drug, was examined to enlighten the degradation mechanism and byproduct formations. Finally, the reactions of cyclohexanone with 3-methyl indole and N-methyl indole, which are the basis of many biologically active compounds, are modeled to determine the origins of regioselectivities.