Chemistry Senior Integrated Projects
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This collection includes Senior Integrated Projects (SIPs, formerly known as Senior Individualized Projects) completed in the Chemistry Department. Abstracts are generally available to the public, but PDF files are available only to current Kalamazoo College students, faculty, and staff. If you are not a current K College student, faculty, or staff member, email us at dspace@kzoo.edu to request access to this material.
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Item Synthesis and Antimicrobial Assessment of Peptoid-Coumarin Hybrids(Kalamazoo College, 2023-11-01) Ramos, Roman; Tresca, Blakely W.Antibiotic-resistant bacteria are a pressing challenge for modern medicine. As treatments become ineffective against drug-resistant bacteria, the need for new antibiotics becomes clear. One strategy for novel antibiotic discovery is the hybridization of different bioactive drugs. Hybrid molecules have the potential to carry over bioactive properties of precursor molecules. Drug candidates with multiple biological targets have increased efficacy. Thus, combination of bioactive molecules with the potential of targeting multiple systems is favorable. A set peptide-coumarin hybrids were discovered with synergistic antibiotic activity against gram-positive bacteria. Moderate antibiotic activity was shown for these compounds. Using the described Tyr-Gly-Ser peptide, a library of peptoids was designed and synthesized. These parent peptoids were combined with coumarins (1) and (2) to create different hybrids. Our peptoid-coumarin were screened for activity by measuring optical density at 600 nm when present in various concentrations below 20 μM in a liquid culture of bacteria. Hybrids with analogous sequences with similar lipophobicity were expected to conserve moderate antibiotic activity in gram-positive bacteria when compared to the peptide-coumarins with the same coumarin. Additionally, hybrids containing more lipophilic coumarins were expected to show increased activity. When tested in within the minimum inhibitory concentration of 20 μM against E. coli and S. aureus, the hybrids did not conserve their observed activities. 10 novel hybrids were synthesized successfully in the solid-phase and were characterized using analytical HPLC. Additional synthesis of various coumarins is planned as the identity heavily influenced the activity of the hybrid.Item Design and Synthesis of 3rd Generation 5-Hydroxy-2-(3-phenylpropyl)chromone Derivatives as 5-HT2B Receptor Ligands(Kalamazoo College, 2024-01-01) Beach, Jenna M.; Williams, Dwight A.Glutamate excitotoxicity is a common pathology of neurodegenerative diseases affecting the central nervous system that leads to neuronal death. Fortunately, 5-hydroxy-2-(2-phenylethyl)chromone (5-HPEC) has shown a reduction in glutamate excitotoxicity in rat cortical cells. Previous studies have observed that 5-hydroxy-2-(2-phenylpropyl)chromone (5-HPPC) in comparison to 5-HPEC is a promising antagonist to the serotonin receptor 2B (5-HT2B) as it has a 10-fold increase in binding affinity with a pKi= 6.6. Based on ligand docking studies, this study aimed to synthesize 5-HPPC derivatives that may improve the hydrogen bonding interactions between the substituents at C-4 and C-5 with serine-139 and threonine-140 and thus further improve the binding affinity for these compounds at the 5-HT2B receptor. To test this hypothesis, three novel analogs were synthesized and the C-4 substituent was varied. Specifically, the thione, hydroxylamine, and hydrazone functional groups were selected. Each analog could be obtained in 56.2%, 103% crude, and 56.4% yield respectively utilizing established chemistries. The NMR for the oxime was indicative that the synthesis was successful. However, the NMR for the hydrazone was less convincing, and other spectra needs to be collected.Item Analysis of Biodegradable Alternatives to Medium Chain Length Chlorinated Paraffins(Kalamazoo College, 2023-11-01) Linehan, William P. III; Hugan, Jason; Mitchell, Josephine W.As an undergraduate chemist at Kalamazoo College, I have been inspired by my educators and mentors to pursue research which adheres to the principles of Green Chemistry. The purpose of the research in this article is to propose a biodegradable alternative to Medium Chain Length Chlorinated Paraffins (MCCPs). MCCPs are a class of highly toxic, persistent, bioaccumulative chemicals which are highly persistent in the metalworking industry due to their effectiveness in lubrication applications. MCCPs degrade into Short Chain Chlorinated Paraffins (SCCPs) over time which have even greater environmental impact. SCCPs have been banned or regulated in most countries since the 1990s and early 2000s, and it is expected that MCCPS will soon be banned or heavily regulated in the United States. Thus, there is a significant need for effective alternatives which are cost competitive. The goal of the research was to study alternative lubricants which are cost-competitive to produce. The additives synthesized and selected were Trimethylpropane trioleate, which is a biodegradable and hydrolytically stable polyol ester, underwent sulfurization, and a stable graphene additive, respectively. The additives were added to a 90:10 base oil additive mixture. The performance and efficiency of the mixtures were measured using Falex Pin and Vee Bar Extreme Pressure tests. Based on the results, we can conclude that the graphene additive was not an effective additive, likely because it was unable to properly provide lamellar protection due to imperfections in the graphene sheets. The Sulfurized oil performed poorly; the data suggests that at low jaw loads the additive had a negative impact on performance. Additionally, the sulfurized oil had a gap in effective temperatures which could potentially be bridged by undergoing phosphorylation. Thus, our research demonstrates that further work is needed to find replacements to medium chain length chlorinated paraffins before they can become regulated without imparting major negative impacts on the metalworking industry.Item Synthesis and Characterization of Bis-hydrazinylpyridine Based Heterobimetallic Catalysts for the Deoxydehydration of Polyols(Kalamazoo College, 2023-11-01) Baker, Lindsey N.; Brewster, TimOne challenge facing industrial chemists is the acquisition of chemical feedstocks such as alkenes from non-petroleum sources to increase sustainability of industrial processes. Deoxydehydration reactions can convert polyols into alkenes, which would allow conversion of biomass into usable chemical feedstocks for modern industry. However, one problem with current deoxydehydration mechanisms is the necessary sacrificial redox agents that greatly increase the cost of this process. The aim of this research is to synthesize and characterize a series of heterobimetallic catalysts capable of both facile activation of hydrogen as the terminal redox agent, as well as perform deoxydehydration catalysis. The monometallic complexes of modified bishydrazinylpyridine ligands with NiII, PtII, PdII, and MoVI were successfully synthesized and characterized. Additional work is in progress to synthesize complexes with IrI, RhI, and RuII, though further purification is necessary to isolate pure material. The synthesized monometallic complexes will provide groundwork for development of the targeted family of heterobimetallic catalysts.Item Designing Phenothiazine Maleimide Hybrids for Antibiotic Applications(Kalamazoo College, 2023-11-01) Kelsey, Blake M.; Williams, Dwight A.Antibiotic resistance is a prevalent health issue concerning the medical field today. Drug resistance can develop in several ways. One of the most prominent methods is deployment of efflux pump. These pumps are responsible for excreting toxic or foreign molecules from the cell before they have an opportunity to harm the cell. One known efflux pump inhibitor is phenothiazine. To combat drug resistance, previous work has been done in the Williams' lab through combination therapy. This therapy is done by synthesizing two known molecules with antibiotic effects and combining them into a hybrid model. One molecule, previously demonstrated in the Williams' lab is 3,4-diarlyl maleimides. The molecule 3,4-diarlyl maleimide has shown antibacterial activity against a variety of bacterial strains. The goal of this study is to find a synthetic route to prepare phenothiazine to complete a Michael addition with diphenylmaleic anhydride. Two approaches were taken to arrive at the key phenothiazine intermediate. In the first approach, the Michael addition of phenothiazine with acrylonitrile followed by reduction with lithium aluminum hydride yielded a crude mixture containing only small amounts of the desired product. In the second approach, N-alkylation using classical substation conditions afforded the desired product in 50% yield after two steps.