Synthesis of 1-hydroxy-2H,5H-dihydroisoxazolo[5,4-c]quinoline. A novel heterocyclic ring system

The synthesis of a new heterocyclic compound, 3a , combining a quinoline and a isoxazolol ring is described. The preparation involves cyclisation of the carbamate 14 , followed by concomitant deprotection of the acidic and amino functions to give compound 3a , the stable tautomeric form of 3 .     

Irregularities in the effect of potassium phosphate in ynamide synthesis

The yields of ynamides using Hsung's second generation protocol depend substantially on the quality of K(3)PO(4). Samples of K(3)PO(4) from different suppliers were investigated by various techniques, revealing that the use of pure and anhydrous K(3)PO(4) provides higher ynamide yields in comparison to samples contaminated with hydrates (K(3)PO(4) x 1.5 H(2)O and K(3)PO(4) x 7 H(2)O). With high quality K(3)PO(4), a number of ynamides were synthesized in yields of 52-91%. In addition, we report that ynamides can undergo regioselective hydroamination with carbamates.     

J(Si,H) Coupling Constants in Nonclassical Transition‐Metal Silane Complexes

We will outline that the sign and magnitude of J(Si,H) coupling constants provide a highly sensitive tool to measure the extent of Si?H bond activation in nonclassical silane complexes. Up to now, this structure–property relationship was obscured by erroneous J(Si,H) sign determinations in the literature. These new findings also help to identify the salient control parameters of the Si?H bond activation process in nonclassical silane complexes.     

Bemerkungen zu dem Aufsatz von W. W. Lepeschkin: „Ueber die kolloidchemische Beschaffenheit der lebenden Substanz usw.“

Ohne Zusammenfassung     

Superparamagnetic and fluorescent thermo-responsive core-shell-corona hybrid nanogels with a protective silica shell

We present the preparation and the characterization of the solution behavior and functional properties of superparamagnetic and/or fluorescent, thermo-responsive inorganic/organic hybrid particles with an intermediate protective silica shell and a smart polymer corona. These well-defined multifunctional nanogels were prepared via two consecutive encapsulation processes of superparamagnetic Fe(2)O(3) nanoparticles (NPs) and/or fluorescent CdSe(ZnS) semiconductor nanocrystals with a silica layer and a crosslinked poly(N-isopropylacrylamide) (PNIPAAm) polymer shell. First, the different NPs were entrapped into a silica shell using a microemulsion process. Therein, the precise adjustment of the conditions allows to entrap either several particles or single ones and to tailor the thickness of the silica shell in the range of 20-60 nm. In a second step, a polymer coating, i.e. thermosensitive PNIPAAm, was attached onto the surface of the multifunctional core-shell particles via free radical precipitation polymerization, furnishing multifunctional core-shell-corona hybrid nanogels. Analyses of the functional properties, i.e. optical brightness and magnetic moments, along with transmission electron microscopy reveal near monodisperse hybrid nanoparticles that retain the intrinsic properties of the original nanocrystals. Additionally, we demonstrate the drastically increased chemical stability due to the barrier properties of the intermediate silica layer that protects and shields the inner functional nanocrystals and the responsive character of the smart PNIPAAm shell.     

Asymptotically optimal quadrature rules for uniform splines over the real line

Numerical Algorithms - We provide explicit asymptotically optimal quadrature rules for uniform Ck-splines, k =?0,1, over the real line. The nodes of these quadrature rules are given in terms...     

Solid-phase synthesis with resin-bound triarylbismuthanes: traceless and multidirectional cleavage of unsymmetrical biphenyls

A multistep solid-phase organic synthesis with resin-bound bismuth linker is described. The flexibilities inherent in this system through novel chemoselective cross-coupling reactions, in conjunction with multidirectional and/or traceless cleavage methodologies, are exploited.     

Electron spin density distribution in the polymer phase of CsC60: assignment of the NMR spectrum

We present high resolution 133Cs-13C double resonance NMR data and 13C-13C NMR correlation spectra of 13C enriched samples of the polymeric phase of CsC60. These data lead to a partial assignment of the lines in the 13C NMR spectrum of CsC60 to the carbon positions on the C60 molecule. A plausible completion of the assignment can be made on the basis of an ab initio calculation. The data support the view that the conduction electron density is concentrated at the C60 "equator," away from the interfullerene bonds.