Background And Objectives: Information communication technologies (ICTs) can enhance older adults' health and well-being. Most research on the use of voice-activated ICTs by older adults has focused on the experiences of individuals living in the community, excluding those who live in long-term care homes. Given evidence of the potential benefits of such technologies to mitigate social isolation and loneliness, more research is needed about their impacts in long-term care home settings.
View Article and Find Full Text PDFThe α-amino-radical constitutes a versatile reactive intermediate that has been used to great effect in the synthesis of complex amine-containing products. Here, we report the development of a multicomponent photocatalytic platform enabling access to all-alkyl α-amino-radicals, exploiting the oxidative formation of silyl-radicals from commercially available tris(trimethylsilyl)silane. A key design element of the new process involves the role of silyl-radicals in generating α-amino-radicals from iminium ions as part of an oxidatively initiated photocatalytic radical chain process.
View Article and Find Full Text PDFThe development of methods for the assembly of secondary α-alkyl amines remains a central challenge to chemical synthesis because of their critical importance in modulating the physical properties of biologically active molecules. Despite decades of intensive research, chemists still rely on selective N-alkylation and carbonyl reductive amination to make most amine products. Here we report the further evolution of a carbonyl alkylative amination process that, for the first time, brings together primary amines, aldehydes and alkyl iodides in a visible-light-mediated multicomponent coupling reaction for the synthesis of a wide range of α-branched secondary alkylamines.
View Article and Find Full Text PDFJ Am Chem Soc
September 2024
Modulating the basicity of alkylamines is a crucial factor in drug design. Consequently, alkylamines with a proximal amide, ester, or ketone have become privileged features in many pharmaceutical candidates. The impact of α-amino carbonyls has made the development of new methods for their preparation a continuous challenge in synthesis.
View Article and Find Full Text PDFIn 2018-2019, Thailand experienced a nationwide spread of chikungunya virus (CHIKV), with approximately 15,000 confirmed cases of disease reported. Here, we investigated the evolutionary and molecular history of the East/Central/South African (ECSA) genotype to determine the origins of the 2018-2019 CHIKV outbreak in Thailand. This was done using newly sequenced clinical samples from travellers returning to Sweden from Thailand in late 2018 and early 2019 and previously published genome sequences.
View Article and Find Full Text PDFAlkyl chlorides are a class of versatile building blocks widely used to generate C(sp)-rich scaffolds through transformation such as nucleophilic substitution, radical addition reactions and metal-catalyzed cross-coupling processes. Despite their utility in the synthesis of high-value functional molecules, distinct methods for the preparation of alkyl chlorides are underrepresented. Here, we report a visible-light-mediated dual catalysis strategy for the modular synthesis of highly functionalized and structurally diverse arylated chloroalkanes via the coupling of diaryliodonium salts, alkenes and potassium chloride.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
October 2024
Transformations enabling the synthesis of α-alkyl, α'-2-azinyl amines by addition of 2-heteroaryl-based nucleophiles to in situ-generated and non-activated alkyl-substituted iminium ions are extremely rare. Approaches involving classical 2-azinyl organometallics, such as the corresponding Grignard reagents, often fail to produce the desired products. Here, we report an operationally straightforward solution to this problem through the development of a multicomponent coupling process wherein a soft 2-azinyl indium nucleophile, generated in situ from the corresponding 2-iodo heteroarene and indium powder, adds to an iminium ion that is also formed directly in the reaction.
View Article and Find Full Text PDFMethods for the synthesis of α-branched alkylamines are important due to their ubiquity in biologically active molecules. Despite the development of many methods for amine preparation, C(sp)-rich nitrogen-containing compounds continue to pose challenges for synthesis. While carbonyl reductive amination (CRA) between ketones and alkylamines is the cornerstone method for α-branched alkylamine synthesis, it is sometimes limited by the sterically demanding condensation step between dialkyl ketones and amines and the more restricted availability of ketones compared to aldehydes.
View Article and Find Full Text PDFA long-standing challenge within radical chemistry is that of controlling the absolute stereochemistry of the products. Here, we report the stereocontrolled addition of α-amino radicals reductively generated from imines via visible-light-mediated photoredox-catalysis to alkenes, giving rise to enantioenriched α-trialkyl-α-tertiary amines. This process exploits a commercially available phenylglycinol derivative as a source of both nitrogen and chiral information.
View Article and Find Full Text PDFHere, we present a remarkably mild and general initiation protocol for alkyl-radical generation from non-activated alkyl-iodides. An interaction between a silane and an alkyl iodide is excited by irradiation with visible light to trigger carbon-iodide bond homolysis and form the alkyl radical. We show how this method can be developed into an operationally simple and general Giese addition reaction that can tolerate a range of sensitive functionalities not normally explored in established approaches to this strategically important transformation.
View Article and Find Full Text PDFLike humans, canine lymphomas are treated by chemotherapy cocktails and frequently develop multiple drug resistance (MDR). Their shortened clinical timelines and tumor accessibility make canines excellent models to study MDR mechanisms. Insulin-sensitizers have been shown to reduce the incidence of cancer in humans prescribed them, and we previously demonstrated that they also reverse and delay MDR development in vitro.
View Article and Find Full Text PDFIntraspecies (homologous) phylogenetic incongruence, or 'tree conflict' between different loci within the same genome of mosquito-borne flaviviruses (MBFV), was first identified in dengue virus (DENV) and subsequently in Japanese encephalitis virus (JEV), St Louis encephalitis virus, and Zika virus (ZIKV). Recently, the first evidence of phylogenetic incongruence between interspecific members of the MBFV was reported in ZIKV and its close relative, Spondweni virus. Uniquely, these hybrid proteomes were derived from four incongruent trees involving an -associated DENV node (1 tree) and three different -associated flavivirus nodes (3 trees).
View Article and Find Full Text PDFIn this cadaveric study, we analysed digital images of dissected palms to define the location and length of superficial connections between the median and the ulnar nerves (Berrettini communicating branches). We found the connections present in 12 of 27 hands. We used a coordinate model to define their location relative to seven specified landmarks.
View Article and Find Full Text PDFStrained aminomethyl-cycloalkanes are a recurrent scaffold in medicinal chemistry due to their unique structural features that give rise to a range of biological properties. Here, we report a palladium-catalyzed enantioselective C(sp)-H arylation of aminomethyl-cyclopropanes and -cyclobutanes with aryl boronic acids. A range of native tertiary alkylamine groups are able to direct C-H cleavage and forge carbon-aryl bonds on the strained cycloalkanes framework as single diastereomers and with excellent enantiomeric ratios.
View Article and Find Full Text PDFVisible-light-activated electron donor-acceptor complexes offer distinct reaction pathways for the synthesis of complex molecules under mild conditions. Herein, we report a method for the reductive generation of α-amino radicals via the reaction of a visible-light-activated ion-pair charge-transfer complex formed between an in situ-generated alkyl-iminium ion and a thiophenolate. This distinct activation mode is demonstrated through the development of a multicomponent coupling reaction to form substituted aminomethyl-cyclopentanes from secondary amines, cyclopropyl aldehydes, and alkenes.
View Article and Find Full Text PDFThe four mosquito-borne dengue virus serotypes (DENV1-DENV4) cause a high burden of disease throughout the tropical and sub-tropical regions of the world. Nevertheless, their precise epidemiological history in Africa, including when and where they originated and were distributed during the 20th century, remains unclear stressing the need for focused research. Accordingly, we conducted a time-scaled molecular epidemiological reconstruction using publicly available and newly sequenced dengue virus genomes of African origin representing all four serotypes to deduce the most likely temporal and spatial transmission routes of each DENV serotype from their ancestral regions to, within and from Africa.
View Article and Find Full Text PDFIncorporation of the fluoromethyl group can profoundly influence the physicochemical properties of organic molecules, offering a promising strategy for the discovery of novel pharmaceutical agents. Direct fluoromethylation of unfunctionalized C(sp) centres can be achieved using fluoromethyl radicals, but current methods for their generation usually rely on the activation of non-commercial or expensive radical precursors inefficient single electron transfer pathways, which limits their synthetic application. Here we report the development of a fluoromethylation strategy based on the generation of fluoromethyl radicals from commercially available fluoroiodomethane halogen atom transfer.
View Article and Find Full Text PDFMolecules displaying an α-trialkyl-α-tertiary amine motif provide access to an important and versatile area of biologically relevant chemical space but are challenging to access through existing synthetic methods. Here, we report an operationally straightforward, multicomponent protocol for the synthesis of a range of functionally and structurally diverse α-trialkyl-α-tertiary amines, which makes use of three readily available components: dialkyl ketones, benzylamines, and alkenes. The strategy relies on the of use visible-light-mediated photocatalysis with readily available Ir(III) complexes to bring about single-electron reduction of an all-alkyl ketimine species to an α-amino radical intermediate; the α-amino radical undergoes Giese-type addition with a variety of alkenes to forge the α-trialkyl-α-tertiary amine center.
View Article and Find Full Text PDFChemically modified biomacromolecules─i.e., proteins, nucleic acids, glycans, and lipids─have become crucial tools in chemical biology.
View Article and Find Full Text PDFMolecules that contain the β-arylethylamine motif have applications in the modulation of pain, treatment of neurological disorders and management of opioid addiction, among others, making it a privileged scaffold in drug discovery. De novo methods for their assembly are reliant on transformations that convert a small class of feedstocks into the target compounds via time-consuming multistep syntheses. Synthetic invention can drive the investigation of the chemical space around this scaffold to further expand its capabilities in biology.
View Article and Find Full Text PDFWe report the development of an operationally straigtforward, visible-light-mediated multicomponent strategy for the construction of β-trifluoromethylated tertiary alkylamines from feedstock aldehydes, secondary amines and a convenient source of trifluoromethyl iodide. The new process does not require a photocatalyst, is metal-free, displays a broad functional group tolerance and offers rapid, one-pot access to trifluoromethylated drug-like compounds that will be of interest in medicinal chemistry.
View Article and Find Full Text PDFBackground: The first successful livebirth using warmed oocytes (vitrified by the GAVI system) is reported in this paper. Embryologists throughout the world have vitrified oocytes using a manual technique which is susceptible to error and variation. In this era of automated laboratory procedures, vitrification was made semi-automatic by using the GAVI system.
View Article and Find Full Text PDFThe all-alkyl α-tertiary amino acid scaffold represents an important structural feature in many biologically and pharmaceutically relevant molecules. Syntheses of this class of molecule, however, often involve multiple steps and require activating auxiliary groups on the nitrogen atom or tailored building blocks. Here, we report a straightforward, single-step, and modular methodology for the synthesis of all-alkyl α-tertiary amino esters.
View Article and Find Full Text PDFSelective chemistry that modifies the structure of DNA and RNA is essential to understanding the role of epigenetic modifications. We report a visible-light-activated photocatalytic process that introduces a covalent modification at a C(sp)-H bond in the methyl group of N6-methyl deoxyadenosine and N6-methyl adenosine, epigenetic modifications of emerging importance. A carefully orchestrated reaction combines reduction of a nitropyridine to form a nitrosopyridine spin-trapping reagent and an exquisitely selective tertiary amine-mediated hydrogen-atom abstraction at the N6-methyl group to form an α-amino radical.
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