Studies in Organosulfur Chemistry

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This research will lead to new methods of synthesizing complex molecules. It is being funded by the Organic and Macromolecular Chemistry Program. This work will permit the investigation of an unusual new class of molecules that contain the cyclic sulfur analog of cyclic peroxides. It has the potential to produce molecules with unusual chemical and biological properties. Four-membered rings with two adjacent sulfur atoms, known as 1,2-dithietanes, are of fundamental theoretical, chemical and biological interest. Although postulated as transient intermediates, no representative of this class of compounds was known as a stable compound until the recent disclosure of the first stable compound in this series, 1,2-dithiatopazine. The chemistry and biology of this compound will be investigated. A series of other 1,2 dithietanes will also be targeted for synthesis and those compounds proven stable will also be studied. The targeted systems were designed to probe the effect of molecular framework flanking the 1,2-dithietane moiety including the size of the adjacent rings and the presence of nitrogen and carbon in them. Molecular mechanics calculations will also be performed in attempts to predict the stability of designed systems. Several alternative methods for the synthesis of thionolactones will be explored. The chemistry of these intermediates will be studied with particular emphasis on new C-C bond forming reactions and cyclic ether formation. Thus, the intermolecular coupling of dithionolactones using electron transfer processes and subsequent chemistry will also be followed as a route to complex polycyclic systems. Dithionoesters will also be synthesized and their intramolecular coupling will be investigated as a means to construct cyclic frameworks. The reasons for the special stability of 1,2-dithiatopazine are not quite clear at present. Calculations on the stability of the systems are expected to lead to intesting predictions which will be tested experimentally. Also theoretical predictions regarding the physical, chemical and biological properties of these molecules are intriguing and will be put to the test. Furthermore, the power and scope to the projected methodology for the formation of the 1,2-dithietanes involving C-C bond formation could be important in ring construction. These fundamental reactions and other extensions involving the thionocarbonyl functionality will be investigated and have the potential of becoming useful synthetic methods.