Synthesis of [5,6]-Bicyclic Heterocycles with a Ring-Junction Nitrogen Atom: Rhodium(III)-Catalyzed C−H Functionalization of Alkenyl Azoles

The first syntheses of privileged [5,6]-bicyclic heterocycles, with ring-junction nitrogen atoms, by transition metal catalyzed C−H functionalization of C-alkenyl azoles is disclosed. Several reactions are applied to alkenyl imidazoles, pyrazoles, and triazoles to provide products with nitrogen incorporated at different sites. Alkyne and diazoketone coupling partners give azolopyridines with various substitution patterns. In addition, 1,4,2-dioxazolone coupling partners yield azolopyrimidines. Furthermore, the mechanisms for the reactions are discussed and the utility of the developed approach is demonstrated by iterative application of C−H functionalization for the rapid synthesis of a patented drug candidate.     

<Emphasis Type="Italic">Ab initio</Emphasis> nuclear structure calculations with transformed realistic interactions

We discuss three elements of modern ab initio nuclear structure theory with an emphasis on the role of correlations in the nuclear many-body problem. Starting from the QCD-motivated construction of a realistic nuclear interaction we review two methods to derive phase-shift equivalent tamed interactions, the Unitary Correlation Operator Method and the Similarity Renormalization Group. Eventually we use these interactions for ab initio calculations within the importance truncated no-core shell model.     

Asymmetric reduction of azirines; a new route to chiral aziridines

The first enantioselective reduction of aromatic 2H-azirines yields aziridines in up to 70% ee, using the aminoalcohol-[RuCl2(p-cymene)]2 catalyzed asymmetric transfer hydrogenation reaction.     

Artifacts,assumptions, and ambiguity: Pitfalls in comparing experimental results to numerical simulations when studying electrical stimulation of the heart

Insidious experimental artifacts and invalid theoretical assumptions complicate the comparison of numerical predictions and observed data. Such difficulties are particularly troublesome when studying electrical stimulation of the heart. During unipolar stimulation of cardiac tissue, the artifacts include nonlinearity of membrane dyes, optical signals blocked by the stimulating electrode, averaging of optical signals with depth, lateral averaging of optical signals, limitations of the current source, and the use of excitation-contraction uncouplers. The assumptions involve electroporation, membrane models, electrode size, the perfusing bath, incorrect model parameters, the applicability of a continuum model, and tissue damage. Comparisons of theory and experiment during far-field stimulation are limited by many of these same factors, plus artifacts from plunge and epicardial recording electrodes and assumptions about the fiber angle at an insulating boundary. These pitfalls must be overcome in order to understand quantitatively how the heart responds to an electrical stimulus. (c) 2002 American Institute of Physics.     

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Far U.V. absorption spectra of manganese halides between 20 and 67 eV.

The absorption spectra of evaporated thin films of MnF₂, MnCl₂, MnBr₂ have been measured in the energy range 20–67 eV. The onset of the absorption of 3p Mn²⁺ is about 50 eV. At lower energies, the structures may be attributed to transitions from 2s F^-, 4s Br^- and 3d Mn²⁺ levels.