Our next webinar will take place via the internet on Tuesday May 24th at 10 AM EDT/3 PM BST. Sign up on our mailing list to receive the Zoom link!
We hope to see/hear from you all at one of our sessions or as one of the next speakers. If you are an early career scientist and would like to present your research, don't hesitate to submit an abstract today! For now, please learn more about our current speakers and their research below. We also thank the generous support from Cell Reports Physical Science, Merck, Janssen, and the Royal Society of Chemistry.
Our featured speakers this week are Wenxin Felix Zhu (Graduate Student, Institute of Pharmaceutical Chemistry, Frankfurt, Germany), and Dr Sebastian Sprick (Principal Investigator, University of Strathclyde, UK). The guest moderator is Dr Sarah Cady from Iowa State University.
LEARN MORE ABOUT THE SPEAKERS AND THEIR TALKS BELOW
WENXIN FELIX ZHU (on Twitter @WFelixZhu)
Biography: Wenxin Felix Zhu studied Chemistry at the Goethe University in Frankfurt, Germany. Currently, he is a Ph.D. candidate at the research group of Prof. Proschak, where he investigates oxadiazolones as cyclic nitrenoid precursors and works on different drug discovery projects. As a medicinal chemist, he gets to collaborate with different researchers and explore various synthetic methodologies. Applying the hit to lead concept to his free time, he likes to plant, cook, and eat whatever survives in his small garden.
Title of Talk: "Cascade Synthesis of Kinase-Privileged 3-Aminoindazoles via Intramolecular N-N Bond Formation"
Abstract: The 3-aminoindazole motif occurs in numerous drug molecules exhibiting a wide range of biological activities. Kinase inhibitors, which have been successfully developed as drugs predominantly for cancer treatment, contain the 3-aminoindazole moiety particularly. Therefore, it is of great interest for the medicinal chemistry community to improve the synthesis of substituted 3-aminoindazoles. From a retrosynthetic perspective, the obvious disconnection is the C-N bond because C-N coupling reactions are well established, and the N-N bond is preinstalled using hydrazine. Indeed, basically all known synthetic methods rely on hydrazines but these are prone to oxidative side reactions and limited in availability. An alternative approach offers the retrosynthetic disconnection of the N-N bond, which would circumvent the beforementioned limitations because amines are widely available and more stable. Thus, amines in ortho position would be coupled with electrophilic nitrenes but these are highly reactive and only occur as intermediates. An emerging strategy to harness the reactivity of nitrenes are the so called cyclic nitrenoid precursors. With decarboxylation as the driving force these functional groups can be utilized as nitrene synthons. Applied to the synthesis of N1-substituted 3-aminoindazoles, the Ullmann-Goldberg condensation of 3-(2-bromoaryl)-1,2,4-oxadiazol-5-ones with amines, which then undergo intramolecular N-N bond formation, represents a potential synthesis route. In this study, we developed this reaction via a microwave-assisted cascade approach. This reaction is characterized by a broad substrate scope including aliphatic and aromatic amines as well as sulfonamides. To the best of our knowledge, this is the first report of a direct access to 3-aminoindazoles with substituted sulfonyl- and aliphatic moieties. Reaction on mmol scale underwent without loss of yield underlining its applicability, in combination with the short reaction time, for fragment-library synthesis. However, this method is limited by very electron poor nucleophiles and excess of nucleophile had to be employed to suppress formation of side product. Furthermore, synthesized compounds were evaluated as fragment-like inhibitors in differential scanning fluorimetry screen of a kinase panel, providing preliminary SAR results and a potential lead structure. In future, we will continue working on the expansion of such kind of intramolecular coupling reactions investigating the reactivity of oxadiazolones as a cyclic nitrenoid precursor. With the results from the kinase panel, selected compounds will be further characterized biologically.
DR SEBASTIAN SPRICK (on Twitter @sebsprick)
Biography: Dr Sebastian Sprick obtained his PhD in Chemistry from The University of Manchester in 2013. He then moved to the University of Liverpool to undertake work as a post-doc before working as a Research Lead in photocatalysis until June 2020. In the summer of 2020, he joined the University of Strathclyde to start his independent research group. His research group has a major research interests across a wide spectrum of polymer chemistry, but with a particular interest addressing challenges in sustainability.
Title of Talk: "Conjugated polymer photocatalysts for hydrogen production from water"
Abstract: Photocatalytic hydrogen production from water is a research area of immense interest as hydrogen has been identified as a potential energy carrier of the future. Most of the studied photocatalysts are inorganic and organic materials have been far less studied, with the exception of carbon nitride materials.
Here, I will present our work on the application of conjugated materials as photocatalysts for hydrogen production from water. We have used a range of different techniques that helped us to gain understanding of the properties that are important for the materials performance. I will briefly discuss how synthetic approaches can be used to tune these properties, and the use of automation to produce a large sets of polymer photocatalysts that were studied for their performance. I will briefly discuss sacrificial water oxidation and non-sacrificial overall water splitting using these materials which shows the potential of these materials for the future for hydrogen production at scale.