Presenter: Madison Fisher, College of Science and Engineering, Physical Science
Authors: Madison M. Fisher and Nathan S. Werner, PhD
Faculty Advisor: Nathan Werner, College of Science and Engineering, Physical Science
Institution: Southern Utah University
Since the discovery of penicillin in 1928, monocyclic β-lactams have been of particular interest because of their antibiotic properties. Due to increasing antibiotic resistance in bacteria, the search for new antibiotics will continue. Our goal is to develop a novel method of synthesizing monocyclic β-lactam (monobactams) antibiotics using more straightforward and efficient synthetic techniques. We plan to accomplish this by using visible-light photoredox catalysis, which utilizes visible light to promote a formal [2+2] cycloaddition of an α,β-unsaturated ketone and an isocyanate to form the monocyclic β-lactam. When we began this project, phenyl isocyanate was the original isocyanate that was evaluated; with this starting material, the reaction yielded no products. After altering the reagents to use hexylisocyanate, we found that a [2+2] cycloaddition had occurred, but only between two molecules of phenyl vinyl ketone (1-phenylprop-2-ene-1-one). We hypothesize that phenyl vinyl ketone will cyclize with an isocyanate to form the intended monobactam if it is prevented from dimerizing. To accomplish this, we are evaluating other catalysts and additives to observe their effect on the reaction. Once productive conditions for the above described reaction are established, the reaction will be optimized, and the antibacterial properties of the monobactams synthesized will be investigated. Through this synthetic method, not only will monobactam antibiotic preparation have more easily accessible starting materials, but the synthesis of various derivatives will also be more easily accomplished; this will be beneficial in the efforts to create new β-lactams to combat the ever-present issue of antibiotic resistance.