27 research outputs found

    Catalytic hydrogenation of α,β-unsaturated carboxylic acid derivatives using copper(i)/N-heterocyclic carbene complexes

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    A simple and air-stable copper(I)/N-heterocyclic carbene complex enables the catalytic hydrogenation of enoates and enamides, hitherto unreactive substrates employing homogeneous copper catalysis and H2 as a terminal reducing agent. This atom economic transformation replaces commonly employed hydrosilanes and can also be carried out in an asymmetric fashion.TU Berlin, Open-Access-Mittel - 201

    Using alcohols as simple H2-equivalents for copper-catalysed transfer semihydrogenations of alkynes

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    Copper(I)/N-heterocyclic carbene complexes enable a transfer semihydrogenation of alkynes employing simple and readily available alcohols such as isopropanol. The practical overall protocol circumvents the use of commonly employed high pressure equipment when using dihydrogen (H2) on the one hand, and avoids the generation of stoichiometric silicon-based waste on the other hand, when hydrosilanes are used as terminal reductants.DFG, 352364740, Diwasserstoff-vermittelte nachhaltige BindungsknüpfungsreaktionenDFG, 53182490, EXC 314: Unifying Concepts in CatalysisTU Berlin, Open-Access-Mittel - 201

    Genotype–phenotype associations within the Li-Fraumeni spectrum: a report from the German Registry

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    Li-Fraumeni syndrome (LFS) is a cancer predisposition syndrome caused by pathogenic TP53 variants. The condition represents one of the most relevant genetic causes of cancer in children and adults due to its frequency and high cancer risk. The term Li-Fraumeni spectrum reflects the evolving phenotypic variability of the condition. Within this spectrum, patients who meet specific LFS criteria are diagnosed with LFS, while patients who do not meet these criteria are diagnosed with attenuated LFS. To explore genotype–phenotype correlations we analyzed 141 individuals from 94 families with pathogenic TP53 variants registered in the German Cancer Predisposition Syndrome Registry. Twenty-one (22%) families had attenuated LFS and 73 (78%) families met the criteria of LFS. NULL variants occurred in 32 (44%) families with LFS and in two (9.5%) families with attenuated LFS (P value < 0.01). Kato partially functional variants were present in 10 out of 53 (19%) families without childhood cancer except adrenocortical carcinoma (ACC) versus 0 out of 41 families with childhood cancer other than ACC alone (P value < 0.01). Our study suggests genotype–phenotype correlations encouraging further analyses. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13045-022-01332-1

    Alles im weißen Bereich?: Institutioneller Rassismus in Sachsen: Erweiterter Tagungsband

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    Die Tagung «Alles im weißen Bereich. Institutioneller Rassismus in Sachsen», die im Februar 2014 stattfand, war die fünfte Tagung in unserer Reihe zu Fragen der Demokratie. Der Gegenstand von Tagung und Sammelband steht für uns einerseits in logischer Reihenfolge bisheriger Fragen und Diskussionen zu den Zuständen Sächsischer Demokratie. Insbesondere war unsere Entscheidung in der Vorbereitung aber auch von der Arbeit der Untersuchungs-ausschüsse zum «NSU» angeregt worden. Ohne den Rassismus, der als grundlegender gesellschaftlicher Wissensbestand existiert, ist die Geschichte und das Versagen des staatlichen Sicherheitsapparates im Zusammenhang mit dem NSU schwer vorstellbar oder nicht möglich. Rassismus ist damit nicht nur das Motiv für die Ermordung von Menschen, sondern auch ein entscheidender Grund dafür, dass diese Morde nicht wirksam verhindert und teilweise nicht oder erst sehr spät aufgeklärt werden können. Diese Feststellung scheint offensichtlich, sie hat sich aber trotz einer breit geführten öffentlichen Debatte und der Arbeit verschiedener Untersuchungsausschüsse als nicht mehrheitsfähig erwiesen. Ebenso wenig konnte Institutioneller Rassismus als Perspektive und Analyseinstrument politisch etabliert werden. Redaktionsschluss: November 201

    Catalytic Hydrogenation of α,β-Unsaturated Carboxylic Acid Derivatives Using copper(I)/N-Heterocyclic Carbene Complexes

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    A simple and air-stable copper(I)/N-heterocyclic carbene complex enables the catalytic hydrogenation of hitherto unreactive enoates and enamides employing H2 as terminal reducing agent. This atom economic transformation replaces commonly employed hydrosilanes and can also be carried out in an asymmetric fashion.<br /

    Von der Halbwaise zur Landesmutter. Familie, Nation und Gender in der Königin Luise-Biographik von 1860 bis 1930

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    Förster B. Von der Halbwaise zur Landesmutter. Familie, Nation und Gender in der Königin Luise-Biographik von 1860 bis 1930. In: von Zimmermann C, von Zimmermann N, eds. Familiengeschichten: Familienstrukturen in biographischen Texten. 2008: 45-62

    Using Alcohols As Simple H2-Equivalents for Copper-Catalysed Transfer Hydrogenations

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    Catalytic transfer hydrogenations are among the most practical synthetic methods for the selective reduction of functional groups. Cheap and readily available dihydrogen (H2) equivalents are highly desirable for catalytic transfer hydrogenations, as inevitably, waste is generated by the formal H2 source. Copper hydride catalysis generally relies on stoichiometric use of waste-generating hydrosilanes. Here, we demonstrate that simple alcohols can be employed as H2 equivalents in stereoselective alkyne semihydrogenations, prototypical copper hydride-catalysed transformations

    Mechanochemical solid state synthesis of a bifunctional copper(I)/N-heterocyclic carbene complex and its catalytic activity in hydrogenative transformations

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    A sophisticated bifunctional catalyst bearing a copper(I)/N-heterocyclic carbene and a guanidine organocatalyst has been prepared by a mechanochemical synthesis in a ball mill. This approach circumvents commonly employed silver(I) complexes which are associated with significant and undesired waste formation. Due to the bifunctional nature of the desired complex, earlier mechanochemical conditions were not applicable and a new protocol based on cheap and readily available K3PO4 as base has been developed. The resulting complex has been shown to be active in a variety of reduction/hydrogenation transformations employing dihydrogen as terminal reducing agent

    A Bifunctional Copper Catalyst Enables Ester Reduction with H2: Expanding the Reactivity Space of Nucleophilic Copper Hydrides

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    Employing a bifunctional catalyst based on a copper(I)/NHC complex and a guanidine organocatalyst, catalytic ester reductions to alcohols with H2 as terminal reducing agent are facilitated. The approach taken here enables the simul-taneous activation of esters through hydrogen bonding and formation of nucleophilic copper(I) hydrides from H2, resulting in a catalytic hydride transfer to esters. The reduction step is further facilitated by a proton shuttle mediated by the guani-dinium subunit. This bifunctional approach to ester reductions for the first time shifts the reactivity of generally considered “soft” copper(I) hydrides to previously unreactive “hard” ester electrophiles and paves the way for a replacement of stoichi-ometric reducing agents by a catalyst and H2.<br /

    Hepatitis A outbreak among MSM in Berlin due to low vaccination coverage: Epidemiology, management, and successful interventions

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    Objectives To describe the characteristics of a large hepatitis A virus (HAV) outbreak among men who have sex with men (MSM) in Berlin and to assess the impact of measures implemented. Methods Cases of laboratory-confirmed, symptomatic HAV infection notified in Berlin, Germany between August 2016 and February 2018 were analysed using routine and enhanced surveillance data including genotyping results. Several studies involving different groups of participants were conducted to further investigate the outbreak, including surveys on knowledge and practices of HAV vaccination among physicians and vaccination coverage and determinants of vaccination status among MSM. The measures implemented were categorized by target group in a Gantt chart. To assess their impact, health insurance data on HAV vaccination uptake were analysed, comparing Berlin and other federal states. Results During the outbreak period, a total of 222 cases were reported (of which 91 were sequence-confirmed), with a peak in case numbers in January 2017. Physicians were aware of the existing vaccination recommendations, but vaccination coverage among 756 MSM was low, with 32.7% being completely vaccinated and 17.3% being incompletely vaccinated before 2017. HAV vaccination before 2017 was associated with being born in Germany (odds ratio 2.36) and HIV-positive (odds ratio 1.80). HAV monovalent vaccination uptake increased by 164% from 2016 to 2017 among males in Berlin, compared to 7% in other federal states. Conclusions Multiple measures targeting the MSM community, physicians, and public health to increase HAV vaccination uptake were successfully implemented. To prevent future HAV outbreaks, we recommend monitoring vaccination coverage among MSM, promoting awareness of existing recommendations among physicians, and ensuring access for foreign-born and young MSM
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