Organic and Materials #2
9:00 - 9:20 am
A New Method for the Synthesis of Tetraarylmethanes
Jake Selingo
Institution: The University of Scranton
Faculty Mentor: Arthur Catino
Tetraarylmethanes contain four aryl groups (typically phenyl) bonded to a central carbon atom. They are used in a wide range of high-tech materials including OLEDs, organic solar cells, and hydrogen storage devices. Despite their importance, there are only a few methods available for their preparation. My group recently reported a general method to prepare tetraarylmethanes with all-phenyl groups and diverse substitution/electronics using an intramolecular Friedel-Crafts reaction followed by a nickel-mediated desulfurization. In this presentation, I will describe my progress toward developing a second-generation approach to tetraarylmethanes that does not require desulfurization.
9:20 - 9:40 am
Synthesis of aristoquinoline
Priyansh Gujarati
Institution: Towson University
Faculty Mentor: Keith Reber
Aristoquinoline is a member of the Aristotelia class of alkaloids that inhibits nicotinic acetylcholine receptors and could therefore have important applications as a novel antidepressant medication. The enantioselective total synthesis of this natural product has been achieved in seven steps and 9.62% overall yield starting from commercially available (-)-α-terpineol. A new route to α-terpinyl amine was developed in order to avoid the toxic and explosive reagent mercury (II) azide. This amine was then coupled with the acid chloride derived from quinoline-4-carboxylic acid to form an amide which underwent an intramolecular nitrilium ion cyclization to form the characteristic [3.3.1]bicycle. Although this bridged Ritter-like reaction formed a 2:1 mixture of endocyclic and exocyclic alkenes, these isomers could be separated using preparative supercritical fluid chromatography (SFC). Subsequent reduction of the imine in the major endocyclic alkene isomer using sodium borohydride occurred with complete diastereoselectivity to afford aristoquinoline.
9:40 - 10:00 am
Solid-Phase Synthesis of Potential Antimicrobial Peptides
Sophia Staggers
Institution: Frostburg State University
Faculty Mentor: Matthew Crawford
Antibiotic resistance is an issue that threatens the efficacy of antibiotic drugs currently available. Peptides present a sustainable alternative to traditional antibiotics because of their versatile antimicrobial effects. Natural Antimicrobial peptides have shown that they possess the ability to kill multi-drug resistant bacteria, fungi, and viruses. Two of the major drawbacks of natural antimicrobial peptides are enzymatic degradation and bioavailability. By creating antimicrobial peptides synthetically, it is possible to reduce enzymatic degradation of the peptides, reduce the cost of acquisition, and increase the overall bioavailability. Fmoc-protected amino acid residues were deprotected using 20% piperidine in dimethylformamide and added to peptide chains upon Tentagel Rink amide resin. The completed peptide sequences were removed from the resin using trifluoroacetic acid (TFA). Solid peptides were dissolved in diluted TFA and analyzed using high-performance liquid chromatography. The peptide sequence ATVVIGTSK was synthesized not only as a whole peptide, but in shortened fragments as well. The antimicrobial potency of each peptide will be determined by measuring the zones of inhibition of bacteria grown on agar plates.
10:00 - 10:20 am
Development of an All-Natural, Organic Power Drink from Aronia Berries
Bokary Sylla
Institution: University of Maryland Eastern Shore
Faculty Mentor: Victoria Volkis
Aronia mitschurinii, also known as chokeberry, is a potential candidate for the next generation of superfruits, as it contains 15 times more antioxidant than Acai berry, and over 40 times more than tomatoes. Fiber powders from the berries contain significant amounts of anthocyanins, indicated by a dark red/purple color. The berry has been found to have antidiabetic, and anti-cancer effects, and protect against various other health issues. Most mainstream power drinks are high in sugars, sodium, and do not claim any antioxidants, minerals or other nutrients. This research revolves around the development of a power drink that is all-natural, organic, using natural sweeteners, with no artificial colorants. The development of a formulation, and technology of production, along with a comparison with other similar products on the market will be presented, as well as chemical analysis of antioxidants, minerals, and sugars and sorbitol, and the influence of processing on these nutrients.
10:20 - 10:40 am
pH Sensitive Polymer Nanoparticle Control for a Lateral Flow Assay for Lead(II) Detection
Rachel Molino
Institution: Elizabethtown College
Faculty Mentor: Lauren Toote
The goal of this research is to develop a lateral flow assay for heavy metals in drinking water, allowing individuals to test water in their homes. Specifically, we focused on developing polymer nanoparticles encapsulating the compound bromocresol green, which will constitute the control for the assay and produce a signal at neutral pH. The resulting nanoparticles were characterized through a variety of methods including DLS, zeta potential, and UV-Vis spectroscopy. Incorporation of the nanoparticles into the lateral flow assay was performed through a streptavidin and biotin interaction. When in acidic conditions, the synthesized nanoparticles bound to the test strip, demonstrating these nanoparticles can be used as the control in our assay. At a basic pH, the opposite result was observed. Future work aims to increase the stability of the control signal by testing nanoparticles encapsulating bromocresol purple, and also synthesizing nanoparticles from block polymers with various component ratios and molecular weights. As a note, I will only be available in the morning due to a scheduled lacrosse game in the afternoon.
11:00 - 11:20 am
Probing Extracts from Specialty Crops, and Herbs as Potential Antifouling Agents
Teemer Barry
Institution: University of Maryland Eastern Shore
Faculty Mentor: Victoria Volkis
Biofouling is the accumulation of marine micro-organisms and their polymerized metabolites on submerged surfaces. Such accumulation creates additional drag and environmental deterioration in marine habitats. Substantial biofilm formation increases fuel consumption, causing significant economic loss to commercial or military vessels. However, the major impact is to the environment, with bacteria in chunks of biofilm, detaching from the ships, as they move across the globe, being largely invasive at habitats different from the origin. To transition from highly toxic biocides busters, and Tributyltin (TBT), and highly expensive hydrophobic polymeric treatments, researchers have sought non-toxic or environmentally friendly alternatives. Our approach is to encapsulate into slow-release biodegradable polymers extracts of antioxidants, terpenes, and essential oils from several natural plant sources, and use it as antifouling formulations. Plant-polymer formulations, antifouling tests with positive results, and surface analysis will be presented.
11:20 - 11:40 am
Understanding the multi-stage geometry of copper sulfide nanorods during Te2- exchange
Haley McAllister
Institution: Franklin and Marshall College
Faculty Mentor: Kate Plass
Copper tellurides are considered high thermoelectric performers, which are in great need due to the current energy crisis. Common production routes include direct synthesis, yet the plausibility of anion exchange is yet to be investigated thoroughly. There are likely advantages to such a synthetic method, for the defects introduced through exchange could make a more efficient thermoelectric device. This research transformed ɑ-chalcocite (Cu2-xS) nanorods into weissite (Cu2-xTe) via anion exchange while still maintaining seed morphology and anion sublattice. Surprisingly, the product did not exhibit regular side effects of anion exchange like the Kirkendall effect. Rationale for this outcome stands at nanoscopic channels induced during exchange, which facilitated equal rates of S2- and Te2- diffusion. EDS-map images also captured the exchange mechanism: core-shell, irregular copper sulfide domains, and, finally, two semi-symmetrical copper sulfide cores. This study offers a different approach to thermoelectric design as well as insights into anion exchange itself.
11:40 - 12:00 pm
Total Synthesis of Strychnuxinal
Neechi Okwor
Institution: Towson University
Faculty Mentor: Keith Reber
In 2018, Sichaem and coworkers isolated the novel phenolic natural product strychnuxinal A from the fruits of the tree Strychnos nux-blanda, which has been used in traditional Thai medicine to treat inflammation and malaria. The purpose of this project is to develop a practical synthetic route to the alkaloid natural product strychnuxinal in yields sufficient for biological testing in association with our group’s academic and industrial collaborators. Specifically, we designed a five-step reaction sequence starting from the reagent (R)-4-chlorostyrene oxide to achieve the total synthesis of the desired compound. The development of an efficient synthetic route to strychnuxinal would provide sufficient quantities of this natural product for evaluations of its biomedical functionality. Further, we anticipate that our proposed synthetic methodology could be of importance in the field of medicinal chemistry for the assembly of a small library of similar compounds.
12:00 - 12:20 pm
Steric-Free Bioorthogonal Fluroine-Thiol Displacement Reaction for Functional Annotation of Post-Translational Modifications
Rifat Nabi
Institution: Temple University
Faculty Mentor: Ross Wang
Alkyne-, or azide-based bioorthogonal reactions have commonly been used for elucidating crucial biological pathways, such as post-translational modifications (PTMs). Despite the versatility in these chemical reporters, they face a major drawback: being bulky. Such limitations, which are observed in the metabolic incorporation by enzymes, compromise the active pursuit of the understanding of PTMs, in our case of acetylation. Thereby, we have developed a novel bioorthogonal reaction that bypasses steric issues, by utilizing the carbon-fluorine bond in fluorinated amino acids. The fluoroacetamide labels can thereby be converted to biotin/fluorophore tags, using the fluorine-thiol displacement reaction (FTDR), which enables the readily detection and imaging of acetyl protein substrates.