The Effect of the Nature and Structure of Adsorbents on Interaction with Ibuprofen

The interaction of ibuprofen [2-(4-isobutylphenyl)propionic acid] with the surface of carbon and oxide adsorbents was investigated. The significant role of wide pores during the adsorption of ibuprofen on carbon adsorbents in the presence of protein molecules was demonstrated. At low concentrations ibuprofen is adsorbed on the surface of hydrophilic and hydrophobic adsorbents in the form of a monomer, but the contribution from the adsorbed dimer increases with increase in its concentration.     

Type II Anion Relay Chemistry: Exploiting Bifunctional Weinreb Amide Linchpins for the One‐Pot Synthesis of Differentiated 1,3‐Diketones,Pyrans, and Spiroketals

The design, synthesis, and validation of new highly effective bifunctional linchpins for type II anion relay chemistry (ARC) has been achieved. The mechanistically novel negative‐charge migration that comprises the Brook rearrangement is now initiated by a stabilized tetrahedral intermediate, which is generated by nucleophilic addition to a Weinreb amide, rather than by a simple oxyanion that is generated from an epoxide. As a result, the linchpin preserves the carbonyl functionality in the ARC adducts, thus permitting access to functionally complex systems in a single flask without the need for further chemical manipulations. This tactic was validated with the one‐pot preparation of monoprotected 1,3‐diketones as well as pyran and spiroketal scaffolds, depending on the choice of nucleophile, electrophile, and work‐up conditions.     

A practical synthesis of (±)-thienamycin

An efficient and operationally simple synthesis of (±)-thienamycin is described.     

Metal Nodes of Metal-Organic Frameworks can Activate Molecular Hydrogen

Hydrogenation of multiple bonds are among the most general and important organic reactions. Typical heterogeneous catalysts are based on transition metal nanoparticles, including noble metals. Data are presented here showing that metal nodes of MIL-101(Cr) and UiO-66 in the absence of occluded metal nanoparticles can promote hydrogenation of polarized X=Y double bonds of nitro and carbonyl groups. The catalytic activity is a function of the composition of the metal node and the organic linker. It is proposed that the reaction mechanism is based on the operation of frustrated Lewis acid/base pairs.     

meso-Me2Si(1-indenyl)2ZrCl2/methylalumoxane catalyzed polymerization of the ethylene to ethyl-branched polyethylene

The meso ansa zirconocene with dimethylsilyl bridge, activated by methylalumoxane, catalyses the ethylene polymerization, producing ethyl-branched polyethylene. With respect to the polymers obtained with the previously investigated meso zirconocenes, we have found higher branching amount and lower molecular weight. The rapid β-H transfer from the growing chain to the coordinated monomer could account for both these features of the polymer. The investigation on the structural parameters of the complex, through X-ray diffraction analysis, and on the electrophilicity of the cationic center, through NMR experiments, suggests, as a possible rationalization of this behavior, the obstruction in the inward site.     

Ligand‐Enabled β‐Methylene C(sp3)−H Arylation of Masked Aliphatic Alcohols

Despite recent advances, reactivity and site‐selectivity remain significant obstacles for the practical application of C(sp³)?H bond functionalization methods. Here, we describe a system that combines a salicylic‐aldehyde‐derived L,X‐type directing group with an electron‐deficient 2‐pyridone ligand to enable the β‐methylene C(sp³)?H arylation of aliphatic alcohols, which has not been possible previously. Notably, this protocol is compatible with heterocycles embedded in both alcohol substrates and aryl coupling partners. A site‐ and stereo‐specific annulation of dihydrocholesterol and the synthesis of a key intermediate of englitazone illustrate the practicality of this method.     

Elastomeric Compounds with Silica. Lower Hysteresis in the Presence of Functionalised Isoprene Oligomers

Silica as reinforcing filler brings about a low hysteresis in elastomeric compounds. Aim of this work was to promote a better silica-elastomer interaction by using, as minor ingredients of a compound, isoprene oligomers having a functional group as the chain end. The effect of the functionality was investigated by analysing the complex viscosity of silica-oligomers binary mixtures as well as the morphological and rheological properties of masterbatches and compounds based on isoprene rubbers. A better silica dispersion and a lower Payne effect were clearly observed in the presence of functionalized oligomers.     

Photoactive Zr and Ti Metal-Organic-Frameworks for Solid-State Solar Cells

Solid-state photovoltaic cells based on robust metal-organic frameworks (MOFs), MIL-125(Ti), MIL-125(Ti)-NH₂, UiO-67, Ru(bpy)₂-UiO-67, (bpy 2,2‘-bipyridine) as active components and spiro-MeOTAD (MeOTAD 2,2‘,7,7‘-tetrakis[N,N-di(p-methoxyphenyl)amino]-9,9′-spirobifluorene) as hole transporting layer have been prepared., The photovoltaic response of this material increases in the presence of bathochromic −NH₂ groups on the linker or Ru (II) polypyridyl complexes light harvester. These results show that the strategies typically employed in photocatalysis to enhance the photocatalytic activity of MOFs can also be applied in the field of photovoltaic devices.     

A concise approach towards the synthesis of WS75624 A and WS75624 B via the cross-metathesis of vinyl-functionalized thiazoles

Synthetic approach towards precursors of WS75624 A and WS75624 B, two potent endothelin converting enzyme (ECE) inhibitors and potential antihypertensive agents, is reported featuring a key cross-metathesis between a vinyl-functionalized thiazole and a terminal olefin. As the two natural products only differ by the nature of their hydroxyalkyl side-chain, our convergent strategy enable the synthesis of key intermediates of both molecules in a limited amount of steps.     

Synthesis of 13C‐Labeled Pyrazinone Thrombin Inhibitors and Elucidation of Metabolic Activation Pathways

In support of a research program aimed at discovering orally bioavailable thrombin inhibitors, ¹³C‐ labeled 3‐aminopyrazinone acetamide thrombin inhibitors have been prepared to aid in the structural elucidation of key metabolites during preclinical and clinical studies. A method for the ¹³C‐labeling of pyrazinones utilizing ¹³C‐glycine as a building block has been developed in a good overall yield. Two targets with labels at different positions have been prepared. NMR Studies not only led to the structure of a major metabolite, but also revealed a likely metabolic pathway, which will provide structural guidance for the design and synthesis of future thrombin inhibitors as well as other pyrazinone‐containing compounds.