Pyrrolizidines for direct air capture and CO2 conversion

Greenhouse gases such as CO2 strongly contribute to the rising temperatures of our planet, but as long as our society is dependent on fossil fuels, this trend will even increase in the near future. Therefore, CO2 capture and subsequent utilization constitute an approach for decarbonization and CO2 mitigation, and for this purpose, amine scrubbing remains the industrially most established process. In this article, we describe the CO2 capture-ability of pyrrolizidine-based diamines, a scaffold with remarkably good properties to fulfill this challenge. We observed fast equimolar CO2-uptake, as well as high stability of these compounds during multiple capture and release-cycles. In addition, the amines could be utilized for direct air capture. Finally, we demonstrate the utility of the pyrrolizidine absorbents in the reduction of CO2 and for the formation of oxazolidinones

Direct preparation of pyrrolizidines using imines and isonitriles

An acid mediated annulation reaction for the formation of 7a-substituted unnatural pyrrolizidines is described. To reach this goal, the pyrroline 3-(3,4-dihydro-2H-pyrrol-5-yl)propan-1-ol is reacted with a large variety of isonitriles directly resulting in the target compounds. The reaction is operationally simple and tolerates air and water, and the resulting pyrrolizidines can be further transformed to the corresponding oxidized and reduced derivatives

Antibiotic Algae by Chemical Surface Engineering

Chemical cell-surface engineering is a tool for modifying and altering cellular functions. Herein, we report the introduction of an antibiotic phenotype to the green alga Chlamydomonas reinhardtii by chemically modifying its cell surface. Flow cytometry and confocal microscopy studies demonstrated that a hybrid of the antibiotic vancomycin anda4-hydroxyproline oligomer binds reversibly to the cell wall without affecting the viability or motility of the cells. The modified cells were used to inhibit bacterial growth of Gram-positive Bacillus subtilis cultures. Delivery of the antibiotic from the microalgae to the bacterial cells was verified by microscopy. Our studies provide compelling evidence that 1) chemical surface engineering constitutes a useful tool for the introduction of new, previously unknown functionality, and 2) living microalgae can serve as new platforms for drug delivery