Some amine hydrofluorides and amines in organofluorine chemistry

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Synthesis of 2,2-difluoro-1,3-diketone and 2,2-difluoro-1,3-ketoester derivatives using fluorine gas

Solutions of 1,3-diketones and 1,3-ketoester derivatives react with fluorine to give the corresponding 2,2-difluoro-1,3-dicarbonyl derivatives in the presence of quinuclidine. Quinuclidine reacts with fluorine in situ to generate a fluoride ion that facilitates limiting enolization processes, and an electrophilic N-F fluorinating agent that is reactive towards neutral enol species

Collaboration Between Content Experts and Assessment Specialists: Using a Validity Argument Framework to Develop a College Mathematics Assessment

Developing a new assessment requires the expertise of both content experts and assessment specialists. Using the example of an assessment developed for Ontario’s Colleges Mathematics Assessment Program (CMAP), this article (1) describes the decisions that must be made in developing a new assessment, (2) explores the complementary contributions of content experts and assessment specialists, and (3) illustrates how the use of a validity argument framework can support collaboration in assessment development. The authors conclude that the validity argument framework facilitated effective collaboration between content experts and assessment specialists, and suggest that this approach may help other collaborators pursue transparent and effective assessment development

Biotransformation of fluorophenyl pyridine carboxylic acids by the model fungus Cunninghamella elegans

1. Fluorine plays a key role in the design of new drugs and recent FDA approvals included two fluorinated drugs, tedizolid phosphate and vorapaxar, both of which contain the fluorophenyl pyridyl moiety. 2. To investigate the likely phase-I (oxidative) metabolic fate of this group, various fluorinated phenyl pyridine carboxylic acids were incubated with the fungus Cunninghamella elegans, which is an established model of mammalian drug metabolism. 3. 19F NMR spectroscopy established the degree of biotransformation, which varied depending on the position of fluorine substitution, and gas chromatography–mass spectrometry (GC–MS) identified alcohols and hydroxylated carboxylic acids as metabolites. The hydroxylated metabolites were further structurally characterised by nuclear magnetic resonance spectroscopy (NMR), which demonstrated that hydroxylation occurred on the 4′ position; fluorine in that position blocked the hydroxylation. 4. The fluorophenyl pyridine carboxylic acids were not biotransformed by rat liver microsomes and this was a consequence of inhibitory action, and thus, the fungal model was crucial in obtaining metabolites to establish the mechanism of catabolism

Non-random spatial distribution of impacts in the Stardust Cometary Collector

We report the discovery that impacts in the Stardust cometary collector are not distributed randomly in the collecting media, but appear to be clustered on scales smaller than ~10 cm