Synthesis and analysis of isomers of unsaturated hydrocarbon Z-alkenes and enantioselective synthesis of heterocycle via desymmetrization
- UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
- Sujata Sigdel (Creator)
- Institution
- The University of North Carolina at Greensboro (UNCG )
- Web Site: http://library.uncg.edu/
- Advisor
- Kimberly Petersen
Abstract: Honeybees are the most important crop pollinators, and they play a major role in the natural ecosystem, scientific innovations, and food security. The health of honeybees is declining due in part to the ectoparasitic mite, Varroa destructor (Varroa). Varroa is a physical burden to honeybees because they feed on the fat body of the brood which negatively impacts the health of the honeybees. Varroa is a physiological burden to its host, but they can be reduced at the colony level through hygienic behavior, the detecting, uncapping, and removing of the diseased or infested brood from the hive by adult bees. The trigger for the hygienic behavior is a chemical signal composed primarily of monoalkenes and produced by unhealthy brood. Numerous hydrocarbons have been associated with unhealthy broods, some of which have shown to trigger hygienic behavior. Some hygiene-inducing compounds have been identified as Z-6 C15, Z-8 C17, Z-8 C31, and Z-10 C33 and are elevated in Varroa-infested brood. Hydrocarbons C25 and C27 have also been known to be associated with unhealthy brood, and recently, the double bond location of the most prominent isomers of C25 and C27 have been identified. The Z-9 isomers of C25 and C27 are found to be a dominant form found in honeybees and are predicted as most biologically active. Z-7 of C25 and C27 have also been identified in honeybees but in a smaller quantity and Z-8 of C25 and C27 have not been previously identified in honeybees, however, its presence is a possibility. This project focuses on synthesizing the Z-isomers of C25 and C27 (Z-7, Z-8, and Z-9) with greater than 95% purity. After the synthesis, these compounds will be tested for biological activity related to hygienic behavior in future field research. Enantioselective synthesis is a key subject in modern chemistry and often important in the field of pharmaceuticals. Enantioselective synthesis is a form of chemical synthesis in which one enantiomer of the chiral product is produced preferentially. Enantiomers are mirror image stereoisomers that are a non-superimposable. A set of two different enantiomers of molecules have different biological activities and functions. A desymmetrization reaction involves a modification where a molecule loses one or more symmetrical features. It is also a technique to synthesize enantiomers. Previous works in Dr. Petersen’s group have dealt with desymmetrization of malonic ester derivatives in the presence of chiral Brønsted acid catalyst to achieve enantioenriched heterocycles. The goal of this project is to use a Knoevenagel condensation, hydrogenation, and cyclization reaction catalyzed by chiral Brønsted acid catalyst to achieve an enantioselective product.
Synthesis and analysis of isomers of unsaturated hydrocarbon Z-alkenes and enantioselective synthesis of heterocycle via desymmetrization
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Created on 8/1/2022
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Additional Information
- Publication
- Thesis
- Language: English
- Date: 2022
- Keywords
- Desymmetrization, Ethyl malonate, Honeybee, Hydrocarbons, Hygienic Behavior, Indole derivatives
- Subjects
- Honeybee $x Behavior
- Varroa destructor
- Hydrocarbons