Synthesis and mechanistic studies of sulfur heterocyclic (benzodithiolanone-oxide) and dioxirane compounds.
Item
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Title
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Synthesis and mechanistic studies of sulfur heterocyclic (benzodithiolanone-oxide) and dioxirane compounds.
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Identifier
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AAI3295016
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identifier
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3295016
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Creator
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Sawwan, Nahed.
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Contributor
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Adviser: Alexander Greer
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Date
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2007
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Language
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English
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Publisher
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City University of New York.
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Subject
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Chemistry, Organic
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Abstract
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This research studies the idea of neighboring group interactions as important variables in the chemistry of sulfur heterocycles (benzodithiolanone-oxide) and 3-membered ring peroxides (dioxiranes). The thesis consists of four parts. The first part of the thesis describes the synthesis of ortho- and para-substituted benzo-1,2-dithiolan-3-one 1-oxides, and investigates their reactivity toward n-propyl thiol reactions in acetonitrilewater mixtures. The reaction with thiol is facilitated by reducing the electron density at the para position, or by placing substituents bearing lone pair electrons ortho to the dithiolanone-oxide reaction center. Through-space and through-bond effects both contribute to the conversion of polysulfane products. The second part of the thesis describes studies of dioxirane stability. Our study of "bis-dioxiranes" aimed to provide an understanding of their stabilities compared to "mono-dioxiranes". Biacetyl reacts with oxone to give bis-dioxirane [3,3'-dimethyl-(3,3')bidioxirane, 3] and mono-dioxirane [1-(3-methyl-dioxiran-3-yl)-ethanone, 2)]. Bis-dioxirane 3 is formed when two oxygens are incorporated into biacetyl, while mono-dioxirane 2 incorporated only one. A greater stability is observed in 3 compared to 2, which is attributed to an alpha-dioxiranyl (anomeric) effect in the former. In contrast, 2 suffers from a destabilizing pi-electron withdrawing effect from the adjacent carbonyl group. The third part of the thesis involves the attempted synthesis of a 1,5-bis-dioxirane from 3,7-dimethyl-1,5-cyclooctanedione (4). The idea here is that the two dioxirane groups might be situated in a syn orientation. It was found that, 4 reacts with oxone to form the monoester compound presumably via a mono-dioxirane, although work on the project is incomplete. There is no evidence was obtained for the 1,5-bis-dioxirane intermediate in this system. Finally, a review of the literature on heteroatom-containing dioxiranes was accomplished, which represents the last chapter of the thesis.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
