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Conference Presentations

TCNJ faculty and students are actively engaged in presenting the results of their work at local, regional, and national conferences. Below is a list of research presentations that have been made by our students.

249th ACS National Meeting & Exposition, Denver, CO, United States, March 22-26, 2015

Shelby C. Allen and Lynn M. Bradley

Formation and reactions of benzyl azetidine compounds

Recent work has focused on the syntheses of benzyl azetidines. The benzyl azetidine system is desired in order to form a tetrahydrobenzazepine system, a compd. containing a seven-membered heterocyclic ring. Tetrahydrobenzazepines have biological activity and can be used in pharmaceutical and medicinal applications. A novel synthesis of benzyl azetidine has been studied using 3-bromopropylamine hydrobromide, triethylamine, and benzyl bromide, and is believed to include a series of SN2 substitution reactions and deprotonations. The variables tested to maximize the product yield of this reaction were molar equivalents of the salt and identity of the base. Thus far, it has been found that the best yield of benzyl azetidine is obtained when using 1.2 molar equivalents of the salt and triethylamine as the base. 1H-NMR, IR, and GC-MS anal. were used to characterize all intermediates and products. Synthesizing benzyl azetidines via the reduction of an imine intermediate has been previously studied in the Bradley group, but yields were low and inconsistent. A more recent literature procedure incorporates suggestions that may help to improve the initial yields obtained, and this will be further explored. Finally, conversion of the 2-bromobenzyl azetidine to the tetrahydrobenzazepine system will be attempted in the near future.

Amy E. Solinski and David A. Hunt

Reaction of 1, 2-cyclohexanedione with diols. An unexpected aromatization reaction

Previous work in our lab had focused on the reaction of 1, 2-cyclohexanedione with bromoaryl alcohols to produce dione ether starting materials (3) for an unrelated study. During this work, we observed an unusual aromatization reaction arising from the dione ether intermediate. This observation led to a study designed to det. the scope of the reaction of 1, 2- cyclohexanedione with a variety of alcohols to prepare compounds of the type (4). This current work describes our efforts to det. the scope and limitations of this chem. with a variety of diols (5) under various conditions.

Cristian Ochoa and Lynn M. Bradley

Efficient methods of synthesizing benzyl azetidines

The purpose of this research project has been to develop new methods for making benzyl azetidines. Benzyl azetidine derivatives. have possible uses in pharmaceutical applications; therefore, different methods of synthesizing these compdounds efficiently are being evaluated. A recent method that has been studied involves making benzyl azetidine by mixing 3- bromopropylamine hydrobromide, tri-Et amine, and benzyl bromide in a relatively straightforward SN2 reaction. Although a number of variables for this reaction have been evaluated in the Bradley lab., this work focuses on results from varying the temperature, solvent, and order of reactants used. The results from the past academic year indicate that all of these variables had a strong effect on the amount of derived product and undesired side products synthesized. The highest yield obtained in the studies was 48.7%. There were two side products formed, detected by GC-MS, that were observed in every experiment and their formation cannot be either explained or avoided. Alternative methods using microwave synthesis offer a new direction for this project; literature has shown that azetidine products can be produced in relatively high yields with good purity. The next phase of this project involves mixing cyclic sulfates and benzylic amines at high temperatures and pressures in order to create benzyl azetidine, hopefully with minimization of side products.

David A. Hunt and Jessica Bocanegra

Copper(I) catalyzed reaction of 1-bromo-2-iodobenzene with 1,2-cyclohexanedione as a potential route to 2,3- dihydrodibenzo[b,d]furan-4(1H)-one

As a potential route to 2, 3-dihydrodibenzo[b,d]furan-4(1H)-one (3), we have been investigating the one-pot process of condensing 1-bromo-2-iodobenzene (1) with 1,2-cyclohexanedione (2) using Cu(I) catalysis. This poster summarizes our efforts in the area to date.

Elizabeth J. Johnson and Heba Abourahma

Kinetic and thermodynamic solubility of pyrazinamide cocrystals

Pharmaceutical cocrystals, which are crystals composed of two distinct compds. at least one of which is an active pharmaceutical ingredient (API), have become of high interest to chemists and the pharmaceutical industry in recent years. Altering the phys. properties of a drug without affecting its therapeutic effectiveness would be ideal for pharmaceutical formulation advancements. Cocrystallization is a potential formulation strategy that can achieve this because cocrystals maintain the chem. properties of the components while changing the phys. properties due to changes in the crystal structure. Properties such as solubility and bioavailability can be affected by cocrystallization. The focus of the present study was to det. the thermodynamic and kinetic solubility of cocrystals of the antituberculosis drug, pyrazinamide (PZA). More specifically, solubility data of cocrystals of PZA and isomers (ortho, o; meta, m; para, p) of hydroxybenzoic acid (HBA), aminobenzoic acid (ABA), nitrobenzoic acid (NBA) and nitrobenzamide (NBZ) were determined No improvement in the thermodynamic solubility of PZA was observed in any of the cocrystals, but enhancement in the kinetic solubility was observed in the case of five cocrystals (PZA•oABA, PZA•oHBA, PZA•mHBA, PZA•oNBA, and PZA•oNBZ).

Taylor Maney, Hussnain Sajjad, Christopher Kirby, Abby R. O’Connor, and Benny C. Chan

Student Chemists Association at The College of New Jersey

The Student Chemists Association (SCA) at The College of New Jersey (TCNJ) is an American Chem. Society Student Chapter dedicated to professional advancement of members and service to the local community. Webinars, as well as a variety of speakers from different fields of chem., are hosted throughout the year, and many upperclassmen members attend lectures, give talks, and present posters at the ACS National Meeting. To facilitate the professional development of freshmen and more generally their acclimation to college life, SCA holds “Happy Hour” events in the fall where freshmen, upperclassmen, and faculty can interact. In terms of service, the club hosts “dry ice bubbles,” “elephant toothpaste,” and “red cabbage indicator” demonstrations at several local elementary and middle schools, as well as at the Ewing Township Community Fest. SCA also volunteers at the Trenton Area Soup Kitchen, for the Ewing Green Team, and during TCNJ Finals Fest, giving out pretzels to stressed-out students while explaining the chem. of lye. Students in need of a study break enjoy “stressbuster” events such as rockclimbing, lasertag, and paintballing all sponsored by the chapter. Perhaps the most successful events are the social activities. Our most popular events are the Departmental Thanksgiving Potluck and Chemistry Semiformal. Here, we detail what we believe are the best practices for an Outstanding ACS Student Chapter.

Abby R. O’Connor and Stephanie E. Sen

Implementation of NMR spectroscopy into the undergraduate experience at The College of New Jersey

The College of New Jersey (TCNJ) is highly committed to the integration of undergraduate research into its curriculum and possesses a strong institutional commitment to faculty scholarship and undergraduate research. In order to support this mission, we received funding from the National Science Foundation (MRI-1125993) and TCNJ in 2012 to purchase two high field NMR spectrometers for the enhancement of teaching and research activities in the department. This award resulted in the purchase of two 400 MHz Bruker NMRs to replace an aging 300 MHz spectrometer and support increased faculty-student research activities and the incorporation of NMR into traditional lab. courses. To date, the instrument has resulted in: (1) 28 presentations at national meetings, 9 peer-reviewed publications, and preliminary results that were used for the submission of 6 external grant proposals, (2) the training of 52 undergraduates for research, and (3) the development of various teaching modules for multiple courses. Here we share our best practices and continued challenges for the implementation of NMR into undergraduate research activities and teaching across the curriculum.

Stephanie E. Sen, Michael Grasso, Joseph Macor, Lyndsay M. Wood, Reshma Jacob, Alexis Jones, Taylor Horsfield, Ashley Tomasello, Jeffery Hitchcock, and Michel Cusson

Unique features of isoprenoid forming enzymes in moths: implications for the biosynthesis of homologous juvenile hormones

The disruption of juvenile hormone (JH) functions has long been viewed as a promising avenue for the control of insect pests. Although the vast majority of insects produce only one form of JH (JH III), the Lepidoptera produce a total of five JHs, including four structural homologs that feature one or more Et side chains. In a key step of JH biosynthesis, three isoprene units (isomers and structural homologs of isopentenyl diphosphate) are formed and undergo a head-to-tail condensation catalyzed by farnesyl diphosphate synthase (FPPS), generating the C15 farnesyl diphosphate – the backbone of JH – or one of its C16-18 structural homologs. We cloned and sequenced FPPS and isopentenyl diphosphate synthase (IPPI) cDNAs from several moth species. A comparison of these sequences with those of organisms -ranging from Drosophila melanogaster to Homo sapiens – revealed several amino acid substitutions within the catalytic cavities that might be responsible for functional differences. We performed a series of substrate activity relationship studies, in combination with several inhibitory studies, and demonstrated that the ability to produce homologous structures was enhanced for the lepidopteran proteins, and that selective inhibition of these proteins could be achieved. These results, in combination with mol. modeling studies, confirm that certain structural differences between lepidopteran and non- lepidopteran proteins exist, and provide direction for the development of lepidopteran-specific insecticial agents based on the inhibition of FPPS and IPPI.

Stephanie E. Sen, Alexis Jones, and Taylor Horsfield

Disruption of insect isoprenoid biosynthesis with pyridinium bisphosphonates

Farnesyl diphosphate synthase (FPPS) catalyzes the condensation of the non-allylic diphosphate, isopentenyl diphosphate (IPP; C5), with the allylic diphosphate primer dimethylallyl diphosphate (DMAPP; C5) to generate the C15 prenyl chain (FPP) used for protein prenylation as well as sterol and terpene biosynthesis. Here, we designed and prepd. a series of pyridinium bisphosphonate (PyrBP) compds., with the aim of selectively inhibiting FPPS of the lepidopteran insect order. FPPSs of Drosophila melanogaster and the spruce budworm, Choristoneura fumiferana, were inhibited by several PyrBPs, and as hypothesized, larger bisphosphonates were more selective for the lepidopteran protein and completely inactive towards dipteran and vertebrate FPPSs. Cell growth of a Drosophila cell line was adversely affected by exposure to PyrPBs that were strongly inhibitory to insect FPPS, although their effect was less pronounced than that obsd. upon exposure to the electron transport disrupter, chlorfenapyr. To assess the impact of PyrBPs on lepidopteran insect growth and development, we performed feeding and topical studies, using the tobacco hornworm, Manduca sexta, as our insect model. The free acid form of a PyrBP and a known bisphosphonate inhibitor of vertebrate FPPS, alendronate, had little to no effect on larval M. sexta; however, the topical application of more lipophilic ester PyrBPs caused decreased growth, incomplete larval molting, cuticle darkening at the site of application, and for those insects who survived, the formation of larval-pupal hybrids. To gain a better understanding of the structural differences that produce selective lepidopteran FPPS inhibition, homol. models of C. fumiferana and D. melanogaster FPPS (CfFPPS-2, and DmFPPS) were prepd. Docking of substrate and PyrBPs demonstrates that differences at the -3 and -4 positions relative to the first aspartate rich motif (FARM) are important factors in the ability of the lepidopteran enzyme to produce homologous isoprenoid structures and to be selectively inhibited by larger PyrBPs.

Margaret Chen, Kyle Webb, Kimberly Benitez, and Jinmo Huang

Voltammetric determination of sulfur-containing biomolecules using screen-printed electrodes

Cysteine and glutathione are involved in many biological processes. Both the reduced and the oxidized forms of the two molecules are present in biological systems. Among a number of analytical techniques used to determine these molecules, electroanalytical technique has demonstrated the advantages of simplicity, fast analysis time, and low cost. In this research, cyclic voltammetry is used to study the electroreactivity of the reduced and oxidized forms of the molecules at various kinds of screen-printed electrodes including carbon, gold, and modified electrodes. The peak potentials and currents are studied in relation to the exptl. parameters of potential ranges, scan rates, and supporting electrolytes. Pulse voltammetry is used to quantify the molecules. The effects of electrode materials and experimental parameters on the electrochemistry of the molecules are discussed. The quantitative determinations for the reduced and oxidized forms of the molecules are compared.

Stephanie E. Sen, Taylor Horsfield, and Alexis Jones

Active site analysis of lepidopteran Farnesyl diphosphate synthase: Implications in omologous juvenile hormone biosynthesis

Juvenile hormone (JH) is a unique sesquiterpenoid, found only in insects, that serves a crit. role in insect growth and development. The biosynthesis of JH has been well documented and is known to follow the mevalonate pathway, producing farnesyl diphosphate (FPP) as a key intermediate, which is formed by the action of FPP synthase (FPPS). Interestingly, the insect order Lepidoptera produces a family of structurally related JH structures, which are derived from the incorporation of propionyl-CoA into the mevalonate pathway and the intermediacy of FPP homologs. To understand the role of FPPS in JH homolog biosynthesis, we prepared homology models of FPPS from four lepidopteran species- Choristoneura fumiferana, Bombyx mori, Manduca sexta, and Pseudaletia unipuncta- using the sequences of FPPS2 cloned from each. The resulting protein structures were assessed for their ability to bind homologous substrates and products, and these results were compared with the known JH homolog titers produced by each species. A correlation between active site volume and homolog size was observed, with residues at -4 and -3 to the first aspartate rich motif (FARM) playing a crit. role. The results of these studies will be presented.