Über die Kondensation von Formisobutyraldol mit Acetaldehyd

Ohne ZusammenfassungAm Schlusse meiner Ausführung angelangt, bitte ich noch meinen verehrten Lehrer Hofrat Adolf Lieben, meinen ergebensten Dank entgegenzunehmen für die freundliche Unterstützung, die er meiner Arbeit durch seine Ratschläge angedeihen ließ, und für das Interesse, das er ihr entgegenbrachte.Auch danke ich hier dem Herrn Privatdozenten Dr. C. Pomeranz für seine freundliche Unterstützung.     

Proteomimetic surface fragments distinguish targets by function

The fragment-centric design promises a means to develop complex xenobiotic protein surface mimetics, but it is challenging to find locally biomimetic structures. To address this issue, foldameric local surface mimetic (LSM) libraries were constructed. Protein affinity patterns, ligand promiscuity and protein druggability were evaluated using pull-down data for targets with various interaction tendencies and levels of homology. LSM probes based on H14 helices exhibited sufficient binding affinities for the detection of both orthosteric and non-orthosteric spots, and overall binding tendencies correlated with the magnitude of the target interactome. Binding was driven by two proteinogenic side chains and LSM probes could distinguish structurally similar proteins with different functions, indicating limited promiscuity. Binding patterns displayed similar side chain enrichment values to those for native protein–protein interfaces implying locally biomimetic behavior. These analyses suggest that in a fragment-centric approach foldameric LSMs can serve as useful probes and building blocks for undruggable protein interfaces.

Foldameric local surface mimetics (LSMs) detect spots at protein surfaces and are promising building blocks in a fragment-centric design of xenobiotic structures and protein–protein interaction inhibitors.     

High‐Pressure Synthesis of Cd(NH3)2[B3O5(NH3)]2: Pioneering the Way to the Substance Class of Ammine Borates

To date, the access to the substance class of borates containing nitrogen, for example, nitridoborates, oxonitridoborates, or amine borates, was an extreme effort owing to the difficult starting materials and reaction conditions. Although a number of compounds containing boron and nitrogen are known, no adduct of ammonia to an inorganic borate has been observed so far. A new synthetic approach starting from the simple educts CdO, B₂O₃, and aqueous ammonia under conditions of 4.7 GPa and 800 °C led to the synthesis of Cd(NH₃)₂[B₃O₅(NH₃)]₂ as the first ammine borate. We thoroughly characterized this compound on the basis of low‐temperature single‐crystal and powder X‐ray diffraction data, IR and Raman spectroscopy, and by quantum theoretical calculations. This contribution shows that the adduct of NH₃ to the BO₃ group of a complex B–O network can be stabilized, opening up a fundamentally new synthetic route to nitrogen‐containing borates.     

Decarboxylative Grob‐Type Fragmentations in the Synthesis of Trisubstituted Z Olefins: Application to Peloruside A,Discodermolide, and Epothilone D

Discriminating elimination : A new method for the synthesis of methyl‐branched trisubstituted Z olefins, a structural motif in many polyketides with anticancer activity, relies on an ^?OH‐induced decarboxylative Grob‐type fragmentation (see scheme; Ms=mesyl). The starting materials are β‐mesyloxy lactones with a quaternary α center, which are prepared by aldol reactions in a diastereo‐ and enantioselective manner.

     

Dynamic fracture of imperfectly bonded lap joints

Summary Dynamic photoelasticity in conjunction with linear elastic fracture mechanics was utilized to study the dynamic behavior of imperfectly bonded single lap joints. Transient phenomena of propagation, reflection and diffraction of explosively generated plane elastic stress field disturbances about the tips of a crack located at the interface between the two adherends are investigated in detail. Fracture mechanics aspects of dynamic initiation under stress wave loading in similar and dissimilar lap joints are discussed.

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Dynamisches Verhalten von imperfekt geklebten, einfach überlappten Klebeverbindungen

Übersicht Das dynamische Verhalten von imperfekt geklebten einfach-überlappten Klebeverbindungen wird mit Hilfe der dynamischen Spannungsoptik im Rahmen der linear-elastischen Bruchmechanik untersucht. Die zeitlich schnell veränderlichen Vorgänge bei der Ausbreitung, Reflexion, Brechung und Beugung von explosiv erzeugten ebenen elastischen Störungen des Spannungsfeldes um die Rißspitze einer an der Trennfläche zweier (verschiedener) Materialien liegenden rißähnlichen Klebeimperfektion werden im Detail behandelt. Bruchmechanische Aspekte der dynamischen Rißinitiation an Klebefehlern unter Spannungs-wellenbelastung in monolithischen und kompositen Lappverbindungen werden diskutiert.