Tag: chirality

Axial-to-central chirality transfer in cyclization processes

Axial-to-central chirality transfer in cyclization processes Substrates, bearing axial chirality, can cyclize intra- or inter-molecularly with concomitant transfer of axial-to-central chirality to produce at least one stereocenter. In order to satisfy a strict definition of axial-to-central chirality transfer, the initial axial chirality must be lost during the cyclization process. Highly functionalized enantiopure carbocycles and heterocycles… Continue reading Axial-to-central chirality transfer in cyclization processes

An efficient palladium catalyst on bentonite for Suzuki-Miyaura reaction at room temperature

An efficient palladium catalyst on bentonite for Suzuki-Miyaura reaction at room temperature Green Chem., 2013, Advance Article DOI: 10.1039/C3GC41469H, Paper Guodong Ding, Weitao Wang, Tao Jiang, Buxing Han The Pd/bentonite catalyst prepared by a simple impregnation method in water is very active and stable for the Suzuki-Miyaura reaction. http://pubs.rsc.org/en/Content/ArticleLanding/2013/GC/C3GC41469H?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract Clays, which are nontoxic, abundant, and… Continue reading An efficient palladium catalyst on bentonite for Suzuki-Miyaura reaction at room temperature

Seeding removes barrier to curious cocrystal

Once the heteronuclear seeds had been used in the lab, the cocrystal formed regardless of whether or not the seeds were used The caffeine•benzoic acid cocrystal that has eluded scientists for 60 years has finally been crystallised Cocrystals are crystalline materials composed of two or more molecules held together within the same crystal lattice. Cocrystallisation… Continue reading Seeding removes barrier to curious cocrystal

Magnetism of single molecule controlled by voltage

The molecule of about 2 nm in size is kept stable between two metal electrodes for several days. Image: Christian Grupe/KIT A team of physicists has succeeded in performing an extraordinary experiment: They demonstrated how magnetism that generally manifests itself by a force between two magnetized objects acts within a single molecule. This discovery is… Continue reading Magnetism of single molecule controlled by voltage

Even bacteria use social networks

  This model shows the role of vesicles, vesicle chains and membrane tubes in M. xanthus biofilms. The scientists believe these connections help cells exchange signals and material. Image: Auer laboratory Using several imaging techniques, Lawrence Berkeley National Laboratory scientists found that a common soil bacterium stays connected by a network of chain-like membranes. They… Continue reading Even bacteria use social networks

Marine Natural Products – Bioactivity & Chemical Ecology

Marine Natural Products – Bioactivity & Chemical Ecology allow slideshare to load……… Marine Natural Products – Bioactivity & Chemical Ecology [Kenneth Boyd, Martina Maria Burtscher & Robbie Mutton] from University of the Highlands and Islands

Crystal structure closes classic carbocation case

  Herb Brown favoured rapidly equilibrating classical enantiomers of the 2-norbornyl cation Winstein proposed the nonclassical structure of the 2-norbornyl cation, now shown to be correct F Scholz et al, Science, 2013, DOI: 10.1126/science.1238849 After more than 60 years, crystals of the 2-norbornyl cation have finally put its ‘nonclassical’ structure, with a pentacoordinate carbon, beyond… Continue reading Crystal structure closes classic carbocation case

Visible-light mediated heterogeneous C-H functionalization: oxidative multi-component reactions using a recyclable titanium dioxide (TiO2) catalyst

  Green Chem., 2013, Advance Article DOI: 10.1039/C3GC40587G, Communication Carlos Vila, Magnus Rueping RWTH Aachen University, Institute of Organic Chemistry, Landoltweg 1, D-52074 Aachen, Germany A new multi-component protocol employing visible-light catalysis using a cheap, robust, readily available and recyclable titanium dioxide catalyst provides a series of [small alpha]-amino amides. Visible-light mediated heterogeneous C-H functionalization:… Continue reading Visible-light mediated heterogeneous C-H functionalization: oxidative multi-component reactions using a recyclable titanium dioxide (TiO2) catalyst

Star-Shaped Macromolecule Grabs Large Anions-Chemists at Indiana University Bloomington have created a symmetrical, five-sided macrocycle that is easy to synthesize and has characteristics that may help expand the molecular tool box available to researchers in biology, chemistry and materials sciences.

cure for diabetes This model shows the five-sided cyanostar macrocycle capturing perchlorate at its center. (Credit: Amar Flood)], Chemists at Indiana University Bloomington have created a symmetrical, five-sided macrocycle that is easy to synthesize and has characteristics that may help expand the molecular tool box available to researchers in biology, chemistry and materials sciences.The molecule,… Continue reading Star-Shaped Macromolecule Grabs Large Anions-Chemists at Indiana University Bloomington have created a symmetrical, five-sided macrocycle that is easy to synthesize and has characteristics that may help expand the molecular tool box available to researchers in biology, chemistry and materials sciences.