Search results for "synthesis"
showing 10 items of 2844 documents
Cover Feature: Highly Enantioselective Kinetic Resolution of Michael Adducts through N-Heterocyclic Carbene Catalysis: An Efficient Asymmetric Route …
2018
Dendrimers consisting of stilbene or distyrylbenzene building blocks synthesis and stability
1999
Abstract On the basis of Wittig-Horner reactions and protection group techniques compound 7 for the core and the components 9a-c and 11a-c for the dendrons were prepared and linked in the final step. The convergent synthesis yielded constitutionally and configurationally pure dendrimers ( 2a-c, 2a'-c' ) which consist of distyrylbenzene units. Their thermo-oxidative stability in the presence of air was studied by chemiluminescence and compared to the dendrimers 1 consisting of stilbene units.
Cover Picture: Asymmetric Oxidative Mannich Reactions (Adv. Synth. Catal. 3/2021)
2021
Organocatalytic Enantioselective Friedel‐Crafts Alkylation Reactions of Pyrroles
2021
ChemInform Abstract: Enantioselective Henry Addition of Methyl 4-Nitrobutyrate to Aldehydes. Chiral Building Blocks for 2-Pyrrolidinones and Other De…
2010
The reaction is applied to a wide range or aromatic and aliphatic aldehydes and proceeds with moderate to good diastereoselectivities.
ChemInform Abstract: Organocatalytic Approach to Benzofused Nitrogen-Containing Heterocycles: Enantioselective Total Synthesis of (+)-Angustureine.
2009
ChemInform Abstract: Asymmetric Synthesis of Fluorinated Isoindolinones Through Palladium-Catalyzed Carbonylative Amination of Enantioenriched Benzyl…
2015
The asymmetric synthesis of fluorinated isoindolinones has been achieved by a palladium-catalyzed aminocarbonylation reaction of the corresponding α-fluoroalkyl o-iodobenzylamines. A base-mediated anti β-hydride elimination process was suggested to explain the partial erosion of the optical purity observed in some cases. This mechanistic rationale enabled the minimization of this partial racemization by fine-tuning the pKa of the base.
Functionalized Fe3O4 nanoparticles: influence of ligand addition sequence and pH during their continuous hydrothermal synthesis
2015
In this study we report various new efficient ways to synthesize and modify in situ magnetite (Fe3O4) iron oxide nanoparticles (NPs). Thanks to an apparatus especially developed for this new method of grafting, the NPs have been synthesized and functionalized by 3,4-dihydroxyhydrocinnamic acid (DHCA) or 3,4-dihydroxy-L-phenylalanine (LDOPA) in one step and under hydrothermal conditions using varying concentration ratios ([organic molecules]/[ferrous and ferric ions]). The organic molecules were added before or after the NP synthesis. The addition of these organic molecules modifies the structure, the morphology, the oxidation degree and the growth of the crystallites. Adding the organic mol…
ChemInform Abstract: Electrosynthesis of Imidazolium Carboxylates.
2014
For the first time the synthesis of imidazolium carboxylates is efficiently achieved by electrochemical reduction of imidazolium salts under very mild conditions.
Climate Over the Ages; Is the Environment Stable?
2010
As described in Chaps. 3 and 4, the advent of oxygenic photosynthesis triggered worldwide environmental changes. A world that had been reductive passed over into a state in which free dioxygen was available in the oceans and the atmosphere. We have already described the likely catastrophic effects on an anaerobic biota, but the changes were much broader than that. Dioxygen in the seas led to major changes in seawater chemistry. Iron, which had previously been soluble as ferrous salts, was precipitated in the ferric form. Copper, which had been insoluble in the anaerobic ocean as cuprous sulphide (Cu+-state), now became moderately soluble in the cupric form (Cu++-state).