Covalent triazine-based frameworks (CTFs) were synthesized in large scale from various monomers. The materials were post-synthetically modified with acid functionalities via gas-phase sulfonation. Acid capacities of up to 0.83 mmol g À1 at sulfonation degrees of up to 10.7 mol% were achieved. SulfonatedCTFs exhibit high specific surface area and porosity as well as excellent thermal stability under aerobic conditions (>300 C). Successful functionalization was verified investigating catalytic activity in the acidcatalyzed hydrolysis of cellobiose to glucose at 150 C in H 2 O. Catalytic activity is mostly affected by porosity, indicating that mesoporosity is beneficial for hydrolysis of cellobiose. Like other sulfonated materials, S-CTFs show low stability under hydrothermal reaction conditions. Recycling of the catalyst is challenging and significant amounts of sulfur leached out of the materials. Nevertheless, gas-phase sulfonation opens a path to tailored solid acids for application in various reactions. S-CTFs form the basis for multi-functional catalysts, containing basic coordination sites for metal catalysts, tunable structural parameters and surface acidity within one sole system.
In recent years, 3-aminopiperidine and 3-aminoazepane have been identified as important pharmacophores that led to the development of drugs having several billion dollar global revenues. Although the number of protocols for the resolution of suitable racemic derivatives is steadily increasing, there is an ongoing demand for new synthetic methods to prepare enantiomerically pure analogs from readily available starting materials. Herein, we report the cyclization of methyl esters derived from natural ornithine and lysine as well as their enantiomeric counterparts. Lactam synthesis was regularly performed on a lab scale of up to 150 mmol per batch. Protection and subsequent reduction to enantiopure 3-(tritylamino)piperidine and 3-(tritylamino)azepane allowed the selective derivatization of the heterocyclic nitrogen. Deprotection gave access to a set of building blocks that were applied to the synthesis of eight molecules reported to be pharmacologically active in drug research. For example, besifloxacin was prepared in only a few steps starting from D-lysine.
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