Synthesis of Small‐Molecule Fluorescent Probes for the In Vitro Imaging of Calcium‐Activated Potassium Channel KCa3.1

Small‐molecule probes for the in vitro imaging of K_Ca3.1 channel‐expressing cells were developed. Senicapoc, showing high affinity and selectivity for the K_Ca3.1 channels, was chosen as the targeting component. BODIPY dyes 15 – 20 were synthesized and connected by a Cu^I‐catalyzed azide–alkyne [3+2]cycloaddition with propargyl ether senicapoc derivative 8 , yielding fluorescently labeled ligands 21 – 26 . The dimethylpyrrole‐based imaging probes 25 and 26 allow staining of K_Ca3.1 channels in NSCLC cells. The specificity was shown by removing the punctate staining pattern by pre‐incubation with senicapoc. The density of K_Ca3.1 channels detected with 25 and by immunostaining was identical. The punctate structure of the labeled channels could also be observed in living cells. Molecular modeling showed binding of the senicapoc‐targeting component towards the binding site within the ion channel and orientation of the linker with the dye along the inner surface of the ion channel.     

Carbocyclization of E,E-1,4-Diphenyl-1,3-butadiene with Dichloroalkanes Mediated by Rieke Metals

The Rieke metal complexes of barium and strontium readily react with E,E-1,4-diphenyl-1,3-butadiene to form metal-diene reagents. Upon treatment with l .n-dichloroalkanes, these metallocycles are transformed into ring derivatives in excellent chemical yield.     

Two Equivalent Reduction of Copper(I) Complexes; Evidence of an Anionic Copper Species

Reactive copper solutions have been prepared by a cold temperature, two equivalent lithium naphthalenide reduction of copper(I) complexes. One equivalent of organic halides react with one equivalent of the anionic copper to yield organocopper reagents.     

Recent advance in heterocyclic organozinc and organomanganese compounds; direct synthetic routes and application in organic synthesis

A practical synthetic route for the preparation of 2-pyridyl and 3-pyridyl derivatives has been accomplished by utilizing a simple coupling reaction of stable 2-pyridylzinc bromides and 3-pyridylzinc bromides. The organozincs used in this study were easily prepared via the direct insertion of active zinc into the corresponding bromopyridines. The subsequent coupling reactions with a variety of different electrophiles have afforded the corresponding coupling products. Using highly active manganese, a variety of Grignard-type organomanganese reagents have been obtained. The subsequent coupling reactions of the resulting organomanganese reagents with several electrophiles have also been accomplished under mild conditions.     

Zur Bestimmung von Eisen und Titan in keramischen Materialien

Ohne Zusammenfassung     

Peroxodicarbonate as a Green Oxidizer for the Selective Degradation of Kraft Lignin into Vanillin

Lignin, the world's largest resource of renewable aromatics, with annually roughly 50 million tons of accruing technical lignin, mainly Kraft lignin, is highly underdeveloped regarding the production of monoaromatics. We demonstrate the oxidative depolymerization of Kraft lignin at 180 °C to produce vanillin 1 in yields up to 6.2 wt % and 92 % referred to the maximum yield gained from the quantification reaction utilizing nitrobenzene. Using peroxodicarbonate (C₂O₆²⁻) as “green” oxidizer for the degradation, toxic and/or harmful reagents are prevented. Also, the formed waste can serve as makeup chemical in the pulping process. Na₂C₂O₆ is synthesized in an ex-cell electrolysis of aqueous Na₂CO₃ at BDD anodes, achieving a yield of Na₂C₂O₆ with 41 %. At least, the oxidation and degradation of Kraft lignin is analysis via UV/Vis and NMR spectroscopy.     

Nonlinear Dynamics of Motivational Flow

Motivational flow is the experience of intrinsic motivation, which is in turn the result of the levels of challenge and skill involvement for a particular task. The level of flow is predictive of the amount of time a person will spend in that task, and it is thought to form a basis for an individual's time allocation between occupational and leisure activities. In this study, 28 university students, many of whom were employed, completed a 7-day log of their daily activities, their duration, and provided ratings of the level of skills and challenges inherent in the task. The logs provided a time series of several hundred points for each participant, which were each subjected to nonlinear dynamical analysis through nonlinear regression. Principal results were: (1) Flow was chaotic for all subjects. (2) The average R ² for the nonlinear models was .22, compared to .02 for the linear counterpart. (3) R ² was higher for people who spent more time at paying jobs. Evidence for individual differences in dynamical character were uncovered.     

Structure–Reactivity Relationship in the Reaction of Highly Reactive Zinc with Alkyl Bromides

Zinc is different! Unlike with magnesium or lithium, the reactions of organic bromides with highly reactive zinc (Zn*) show sensitivity for the structure of the organic moiety. Selective insertions of Zn into tertiary C–Br bonds can be achieved [Eq. (a)]. Competitive kinetic techniques were used to quantify these findings.