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Herein is reported an innovative and reproducible systemic approach for the fabrication of customized 3D hollow microspheres of polyvinyl alcohol (PVA) based on the use of aromatic boronic acids (ABAs) as crosslinkers. A dedicated experimental set-up was developed to enable microsphere formulation. Most of the boronic acids tested were able to produce hollow microspheres. Depending on the ABA used and the production conditions, hollow PVA/ABA microspheres with different morphologies, mass transfer characteristics and unprecedented thermal (up to 121 °C) stability were obtained. The crosslinking temperature proved to be an operational parameter to control membrane thickness. The hollow microspheres were evaluated in biocatalysis, with naringin hydrolysis as model system, using encapsulated naringinase. The results highlighted a naringinase high operational stability, namely in PVA microspheres crosslinked with 1,4-phenylenediboronic acid and with phenylboronic acid, with no evident loss of activity throughout seven consecutive runs, theoretically resulting in an infinite half-life. [ABSTRACT FROM AUTHOR]

α-Phosphono-lactams were obtained, with high regio and stereoselectivities via Rh2(OAc)4-catalysed intramolecular C&z.sbnd;H insertion in an ionic liquid. This system proved to be highly efficient over 5–6 cycles. [Copyright &y& Elsevier]

Polyvinyl alcohol (PVA) electrospun nanofibers were produced using an electrospinning technique. Key parameters (e.g. collectors, distance from needle tip to collector, among others) that influence the structure and morphology of fibers were optimized. The naringinase entrapped in PVA nanofibers retained over 100% of its initial activity after 212 h of operation, at 25 °C. Chemical crosslinking with several boronic acids further increased the hydrolysis temperature (up to 85 °C) and yielded nanofibers with thermal stability up to 121 °C. A mini packed bed reactor (PBR) developed to establish the feasibility for continuous enzymatic operation, ran for 16 days at 45 °C. Highest naringenin biosynthesis was attained at a flow rate of 10 mL h −1 . Highest volumetric (78 mol L −1 h −1 ) and specific (26 mol h −1 g enzyme −1 ) productivities were attained at 30 mL h −1 . The activity of NGase in electrospun nanofibers remained constant for almost 16 days of operation at 10 mL h −1 . [ABSTRACT FROM AUTHOR]

Abstract: Novel ionic liquid (IL) sol–gel materials development, for enzyme immobilization, was the goal of this work. The deglycosylation of natural glycosides were performed with α-l-rhamnosidase and β-d-glucosidase activities expressed by naringinase. To attain that goal ILs with different structures were incorporated in TMOS/Glycerol sol–gel matrices and used on naringinase immobilization. The most striking feature of ILs incorporation on TMOS/Glycerol matrices was the positive impact on the enzyme activity and stability, which were evaluated in fifty consecutive runs. The efficiency of α-rhamnosidase expressed by naringinase TMOS/Glycerol@ILs matrices increased with cation hydrophobicity as follows: [OMIM]>[BMIM]>[EMIM]>[C2OHMIM]>[BIM] and [OMIM]≈[E2-MPy]≫[E3-MPy]. Regarding the imidazolium family, the hydrophobic nature of the cation resulted in higher α-rhamnosidase efficiencies: [BMIM]BF4 ≫[C2OHMIM]BF4 ≫[BIM]BF4. Small differences in the IL cation structure resulted in important differences in the enzyme activity and stability, namely [E3-MPy] and [E2-MPy] allowed an impressive difference in the α-rhamnosidase activity and stability of almost 150%. The hydrophobic nature of the anion influenced positively α-rhamnosidase activity and stability. In the BMIM series the more hydrophobic anions (PF6 −, BF4 − and Tf2N−) led to higher activities than TFA. SEM analysis showed that the matrices are shaped lens with a film structure which varies within the lens, depending on the presence and the nature of the IL. The kinetics parameters, using naringin and prunin as substrates, were evaluated with free and naringinase encapsulated, respectively on TMOS/Glycerol@[OMIM][Tf2N] and TMOS/Glycerol@[C2OHMIM][PF6] and on TMOS/Glycerol. An improved stability and efficiency of α-l-rhamnosidase and β-glucosidase expressed by encapsulated naringinase on TMOS/Glycerol@[OMIM][Tf2N] and TMOS/Glycerol@[C2OHMIM][PF6] were achieved. In addition to these advantageous, with ILs as sol–gel templates, environmental friendly processes can be implemented. [Copyright &y& Elsevier]

Abstract: Here is described the preparation of four new rhodium(II) complexes bearing axial NHC ligands. The presence of electron-withdrawing bridging ligands resulted in an enhanced reactivity in the arylation of aldehydes with boronic acids when compared with the tetraacetate counterparts. Complex 15 (Rh2tfa4(IPr)2) proved to be the most active catalyst for this transformation allowing the selective conversion of aromatic, aliphatic and vinyl aldehydes into the respective alcohols in excellent yields. It was demonstrated that the good group tolerance could be further extended to aromatic and conjugated ketones. DFT calculations carried out on this system showed the complementarily of the bridging ligands and axial ligand in these dinuclear complexes. It was also disclosed that Rh(II)/NHC catalytic system can promote the racemization of 1-phenyl ethanol. [ABSTRACT FROM AUTHOR]

Abstract: Water is a suitable medium for the Petasis-borono-Mannich multicomponent reaction. Salicylaldehyde, glyoxalic acid, glycoaldehyde and glyoxal were reacted with several boronic acids and different amines affording alkylaminophenols, 2H-chromenes, α-amino acids, α-amino alcohols and 2-hydroxylmorpholines in good to high yields. An efficient new one-pot method for the assembly of boron-heterocycles based on amino-acids, boronic acids and salicylaldehyde using water as the reaction media is presented. The mechanisms of these reactions were studied by means of DFT calculations, and the effect of solvent on the calculated energy barriers was addressed, for different aldehydes. [Copyright &y& Elsevier]

Abstract: In this work we show that the intramolecular C–H insertion of diazo-acetamides catalysed by di-rhodium(II) complexes can be highly influenced by the axial ligand on the di-rhodium(II) complex. Axially monocoordinated NHC–Rh2(OAc)4 complexes have a distinct reactivity from the parent Rh2(OAc)4 complex affording the cyclisation products in different rates and selectivities. Surprisingly, a new reaction mode emerged when using these complexes which led to a decarbonylation pathway. [Copyright &y& Elsevier]

Abstract: A novel dirhodium complex (Rh2(L-PheAla)2(OAc)2 is reported with strong activity towards human colon adenocarcinoma cells. Its effect was not accompanied by generation of reactive oxygen species (ROS) neither by activation of caspase-3. [Copyright &y& Elsevier]

Herein we show that the 3-hydroxyquinolin-2(1 H)-one (3HQ) core is a suitable platform to develop new compounds with anticancer activity against MCF-7 (IC 50 up to 4.82 μM) and NCI–H460 (IC 50 up to 1.8 μM) cancer cell lines. The ring-expansion reaction of isatins with diazo esters catalysed by di-rhodium (II) complexes proved to be a simple and effective strategy to synthesize 4-carboxylate-3HQs (yields up to 92%). 4-Carboxamide-3HQs were more efficiently prepared using NHS-diazoacetate in yields up to 88%. This innovative methodology enabled the construction of "peptidic-like" 3HQs, with several amino acid substituents. Among this series, the L-leucine derivative induced the cell death of MCF-7 (IC 50 of 15.1 μM) and NCI–H460 (IC 50 of 2.7 μM) cancer cell lines without causing any appreciable cytotoxicity against the non-cancer cell model (CHOK1). To create your abstract, type over the instructions in the template box below. Fonts or abstract dimensions should not be changed or altered. Leave this area blank for abstract info. Image 1 [ABSTRACT FROM AUTHOR]