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4-Membered Ring Carbocations: A Positive Development in the Synthesis of 3,3-Disubstituted Oxetanes and Azetidines
Get PDF4-Membered heterocycles are low molecular weight polar scaffolds with intriguing potential for drug discovery. Despite their unquestionable value, methods to access such heterocycles remain scant. Here, we describe the generation of oxetane- and azetidine- benzylic carbocations as a general strategy to access valuable 3,3-disubstituted derivatives
Chemical Recycling of Polymethacrylates Synthesized by RAFT Polymerization
Get PDFReversing controlled radical polymerization and regenerating the monomer has been a long-standing challenge for fundamental research and practical applications. Herein, we report a highly efficient depolymerization method for various polymethacrylates synthesized by reversible addition-fragmentation chain-transfer (RAFT) polymerization. The depolymerization process, which does not require any catalyst, exhibits near-quantitative conversions of up to 92%. The key aspect of our approach is the utilization of the high end-group fidelity of RAFT polymers to generate chain-end radicals at 120 °C. These radicals trigger a rapid unzipping of the polymethacrylates. The depolymerization product can be utilized to either reconstruct the linear polymer or create an entirely new insoluble gel that can also be subjected to depolymerization. Our depolymerization strategy offers a promising route towards the development of sustainable and efficient recycling methods for complex polymer materials
Enantioselective Switch and Potential Applications in Biocatalysis
Get PDFEnantioselectivity has always been a key feature of enzymatic synthesis. In some cases, when enzymes are not strictly enantioselective, by tuning the reaction conditions it is possible to induce an enantioselective switch. A transaminase from Halomonas elongata (ω-HeWT), while generally S-selective, could be shifted towards generating the R-enantiomer at higher concentrations of amino acceptor or ionic strength, for example. Other enzymes are reported to have a similar behavior, and here we discuss some of them and their potential applications
Design of a Biocatalytic Flow Reactor Based on Hierarchically Structured Monolithic Silica for Producing Galactooligosaccharides (GOSs)
Get PDFClimate change mitigation requires the development of greener chemical processes. In this context, biocatalysis is a pivotal key enabling technology. The advantages of biocatalysis include lower energy consumption levels, reduced hazardous waste production and safer processes. The possibility to carry out biocatalytic reactions under flow conditions provides the additional advantage to retain the biocatalyst and to reduce costly downstream processes. Herein, we report a method to produce galactooligosaccharides (GOSs) from a largely available feedstock (i.e. lactose from dairy production) using a flow reactor based on hierarchically structured monolithic silica. This reactor allows for fast and efficient biotransformation reaction in flow conditions
molQueST Conference, August 21st to 25th 2022, Congressi Stefano Franscini (CSF) Conference Center, Monte Verità, Switzerland
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For the Sake of Making Molecules: Paracelsus Prize 2022
No full textThe aim of this article, while reviewing part of my research activities, is to illustrate the somewhat chaotic way leading from one specific topic to another – from e.g. ferrocenyl ligands for asymmetric catalysis, to asymmetric fluorination, to reagents for perfluoroalkylation, just to mention some of the most fruitful ones. That the way meandering through several areas of research in chemical synthesis can be described as chaotic is not primarily due to my inability to plan the work of my research group. In the contrary, it is argued that academic research, viewed as mean to educating and forming young researchers, should resist the temptation towards an increasing projectification, milestone mentality, the myth of societal relevance, and consciously aim for a more anarchical trait, much in the sense of Feyerabend’s “anything goes”
How Technical Innovations May Help to Prevent Drug Shortages in Switzerland
Get PDFIn this work, we investigated the technical feasibility of \u27on-demand\u27 production of selected drugs to cover their demand for a time window of 90 days. We focused on two sub-processes \u27automated chemical synthesis\u27 and \u27formulation in micropellets\u27 to enable personalized dosing. The production of drugs \u27on-demand\u27 is challenging, important, but also attractive. Switzerland could thus gain access to an additional instrument for increasing resilience for supply-critical drugs. The biggest challenge in the case study presented here is the scalability of automated chemical synthesis and the application range of micropellet formulations
Editorial: Swiss TPH: 30 Years of R&D Towards New Drugs for Tropical Diseases
Get PDFThe year 2023 marks the 80th anniversary of the Swiss Tropical and Public Health Institute (Swiss TPH). Associated with the University of Basel, Swiss TPH combines research, education and services, working across a value chain from innovation and validation to application to improve people’s health and well-being. Around 700 staff and students work in Swiss TPH’s new headquarters in an emerging life-science cluster in Allschwil, Switzerland, focusing on infectious and non-communicable diseases, environment, society and health as well as health systems and interventions. In this special issue of Chimia, we highlight 30 years of research and development (R&D) at Swiss TPH, deeply grounded in partnership, towards new drugs for tropical diseases