Scalable Process for 4‐(2‐Hydroxy‐2‐methyl)‐ethyl‐benzylamine

The preparation of the title compound has been revisited and improved. Starting from inexpensive cuminonitrile, 4‐(2‐hydroxy‐2‐methyl)‐ethyl‐benzylamine is obtained in a scalable two‐step process with an overall yield of 55%.     

Solvent‐free synthesis of rotaxanes

Rotaxane‐type (macro)molecules are important materials in various fields of research, with many approaches for their synthesis having been developed over the past 30 years or so. When prepared in solution, the efficiency of interlocking pseudorotaxane complexes into the corresponding rotaxanes relies, to a great extent, on the affinity between the host and guest components; these interactions are not always sufficiently strong to overcome the deleterious effects of high reaction temperatures, competitive solvents, and low concentrations. Upon evaporating the solvent, however, the concentrations of the host and guest species increase significantly and, ultimately, their corresponding pseudorotaxanes can be generated with high efficiency in the solvent‐free residue. Furthermore, in the absence of the solvent, the influence of any disrupting byproducts (generated during the interlocking process) on the complexation equilibrium can also be largely reduced. Therefore, high synthetic efficiency and low consumption of solvents and energy can be expected when synthesizing rotaxanes under solvent‐free conditions. This mini‐review covers the main publications dealing with the solvent‐free syntheses of rotaxanes – those in which the interlocking step involves no solvent (or only a trace of it).     

Preparation of pH- and thermo-sensitive chitosan-PNIPAAm core–shell nanoparticles and evaluation as drug carriers

Environmentally sensitive polysaccharide nanoparticles (NPs) were prepared by in situ polymerization of N-isopropylacrylamide (NIPAAm) monomer in the presence of chitosan (CS) micelles. First, CS was found to develop a cationic micelle-like structure in the acetic acid solution when its concentration was increased to above the critical micelle concentration, as evidenced by fluorescence and TEM. When the NIPAAm was polymerized in the CS micelle solution by using potassium persulfate as initiator, the produced PNIPAAm with anionic chain end(s) became hydrophobic, as long as the reaction temperature was above its phase transition temperature; and therefore it would diffuse into the hydrophobic core of the CS micelles, producing CS-PNIPAAm core–shell NPs. Increasing the feeding amount of NIPAAm increased the monomer conversion and therefore the particle size; yet it decreased the surface zeta potential. Moreover, the CS-PNIPAAm NPs were sensitive to both pH value and temperature. For the study of drug release properties, doxycycline hyclate was used as a model drug and loaded into the NPs at pH 4.5 and 25 °C. The result illustrated that these NPs had a continuous drug release behavior up to 1 week, depending on the pH value and temperature. In addition, enzyme or hydrogen peroxide capable of degrading CS shell was added in the solution to facilitate the drug release.     

Fabrication of Electrospun Polymer Fibers with Nonspherical Cross‐Sections Using a Nanopressing Technique

The fabrication of electrospun polymer fibers is demonstrated with anisotropic cross‐sections by applying a simple pressing method. Electrospun polystyrene or poly(methyl methacrylate) fibers are pressed by flat or patterned substrates while the samples are annealed at elevated temperatures. The shapes and morphologies of the pressed polymer fibers are controlled by the experimental conditions such as the pressing force, the pressing temperature, the pressing time, and the surface pattern of the substrate. At the same pressing force, the shape changes of the polymer fibers can be controlled by the pressing time. For shorter pressing times, the deformation process is dominated by the effect of pressing and fibers with barrel‐shaped cross‐sections can be generated. For longer pressing times, the effect of wetting becomes more important and fibers with dumbbell‐shaped cross‐sections can be obtained. Hierarchical polymer fibers with nanorods are fabricated by pressing the fibers with porous anodic aluminum oxide templates.

     

Magnetically polymeric nanocarriers for targeting delivery of curcumin and hyperthermia treatments toward cancer cells

Magnetically polymeric nanocarriers, Cur‐FA‐SAMN, were designed and synthesized for targeting, therapeutic treatments to cancer cells. Amine‐group immobilized iron oxides, Fe₃O₄‐NH₂, were attached on the surface of self‐assembled tri‐block copolymer, poly[(acrylic acid)‐block‐(N‐isopropylacrylamide)‐block‐(acrylic acid)] synthesized via reversible addition‐fragmentation chain‐transfer polymerization. For the purpose of targeting effect, folic acid was grafted on the surface of Fe₃O₄‐NH₂ attached nanoparticles. The nanocarriers were characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, vibrating sample magnetometer, and UV‐Vis spectral analysis. Therefore, a hydrophobic anti‐cancer drug, curcumin, gained water dispersity, and stable storage via encapsulating into and on the magnetically polymeric nanocarriers, and the release behaviors were studied in vitro, with and without high frequency magnetic field. Biocompatibility and cytotoxicity of inherent and curcumin‐loaded nanocarriers were investigated by MTT assay. Results displayed that our nanocarriers have no cytotoxicity while curcumin‐loaded nanocarriers offered significant death to MCF‐7, human breast camcer cells. Intracellular‐uptake experiments demonstrated tremendous uptake and the destroying effect to MCF‐7 cells, most of the cancer cells were killed and the surviving ones were surrounded by the curcumin‐loaded nanocarriers. According to the aforementioned characteristics, these magnetically polymeric nanocarriers will be able to apply as a potential device for practical therapy. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 2706–2713     

Biohydrogen Production from Mushroom Cultivation Waste by Anaerobic Solid‐state Fermentation

Mushroom cultivation waste (MCW) is a polypropylene bag stuffed with wood flour and nutrients for growing mushroom, which is a feasible feedstock for anaerobic biohydrogen production owing to its abundant availability, high organic and nutrient content. This study optimized the seed inoculum from various waste sludges (sewage sludge, cow dung and pig slurry), nutrient addition and operation conditions (moisture content and MCW powder particle size) for maximal biohydrogen production by solid‐state fermentation (SSF). SSF batch test was operated at a MCW 3 g total volatile solid (TVS)/L, temperature 55 °C and rotation speed of 15 rpm with a vertical rotative shaker. The peak hydrogen production performance of hydrogen production rate (HPR) 9.50 mol H₂/kg‐d and hydrogen yield (HY) 0.29 mmol H₂/g TVS) are obtained using sewage sludge 2 seed inoculum, nutrients addition, moisture content 70 % and particle size of 1.190～0.590 mm. The results show that the MCW has the potential for hydrogen production by anaerobic mixed microflora using solid‐state fermentation. The bioenergy of 1842 kWh while using SSF to conver MCW to produce biohydrogen and it could reduce CO₂ emission of 114–178 kg per year comparing using fossil fuel such as coal, fuel oil and natural gas.     

Thermoresponsive conductive polymer composite thin film and fiber mat: Crosslinked PEDOT:PSS and P(NIPAAm‐co‐NMA) composite

The thermoresponsive conductive composite (TCC) thin films and fiber mats, whose electrical property changed with temperature, were fabricated successfully. The thermocrosslinkable and thermoresponsive copolymer, poly(N‐isopropyl acrylamide‐co‐N‐methylolacrylamide) (PNN), was synthesized. The TCC thin film and fiber mat were fabricated by spin coating and electrospinning process of PEDOT:PSS/PNN solutions, respectively. After thermocrosslinking and doping by DMSO, the composite thin films and fiber mats were obtained. Fibrous structures of TCC fiber mats were observed by SEM. The surface resistance and conductivity of composites were measured. The thermoresponsivity and swelling ratio of TCCs were also studied. The thermoresponsive conductive property was analyzed by measuring the surface resistance of TCCs in water bath under various temperatures from 20 to 50 °C. With the increase of temperature, the TCCs shrank to be dense structure and showed lower surface resistance. The TCC fibers mat exhibited greater sensitivity to temperature than thin film owing to its fibrous structure. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1078–1087     

Silicon Carbide Nanostructures from Reactions between Vapors of Organochlorosilanes and Liquid of Sodium‐Factors Affecting Morphology and Composition

Cubic shells and spherical nanoparticles of β‐SiC were produced at 1273 K by processing the ceramic precursors formed from the reactions between vapors of organochlorosilanes, Me₂SiCl₂, MeSiCl₃, MeSiHCl₂, and PhSiCl₃, and liquid Na at 523‐723 K. From Me₂SiCl₂, a flexible linear polycarbosilane precursor was synthesized and covered the NaCl byproduct surface to form a cubic shape. Hollow cubic β‐SiC shells were produced after the NaCl templates were removed. From MeSiCl₃, a rigid cross‐linked polycarbosilane was produced and phase segregated from the NaCl byproduct. The precursor was transformed into nanoparticles without special morphology. MeSiHCl₂ produced a cross‐linked polysilane precursor at low temperatures, which can be converted into a mixture of β‐SiC and Si nanoparticles. At high temperatures, the polysilane converted to polycarbosilane and produced hollow cubic β‐SiC shells. The carbon‐rich PhSiCl₃ generated cube‐like particles as the final product, which contained β‐SiC and carbon.     

D3R grand challenge 2015: Evaluation of protein–ligand pose and affinity predictions

The Drug Design Data Resource (D3R) ran Grand Challenge 2015 between September 2015 and February 2016. Two targets served as the framework to test community docking and scoring methods: (1) HSP90, donated by AbbVie and the Community Structure Activity Resource (CSAR), and (2) MAP4K4, donated by Genentech. The challenges for both target datasets were conducted in two stages, with the first stage testing pose predictions and the capacity to rank compounds by affinity with minimal structural data; and the second stage testing methods for ranking compounds with knowledge of at least a subset of the ligand–protein poses. An additional sub-challenge provided small groups of chemically similar HSP90 compounds amenable to alchemical calculations of relative binding free energy. Unlike previous blinded Challenges, we did not provide cognate receptors or receptors prepared with hydrogens and likewise did not require a specified crystal structure to be used for pose or affinity prediction in Stage 1. Given the freedom to select from over 200 crystal structures of HSP90 in the PDB, participants employed workflows that tested not only core docking and scoring technologies, but also methods for addressing water-mediated ligand–protein interactions, binding pocket flexibility, and the optimal selection of protein structures for use in docking calculations. Nearly 40 participating groups submitted over 350 prediction sets for Grand Challenge 2015. This overview describes the datasets and the organization of the challenge components, summarizes the results across all submitted predictions, and considers broad conclusions that may be drawn from this collaborative community endeavor.     

Control of nanoparticle location in block copolymers

A simple procedure is described to incorporate gold nanoparticles and control their location within symmetric poly(styrene-b-2 vinyl pyridine) (PS-PVP) diblock copolymers. Gold nanoparticles coated with thiol-terminated PS and/or PVP homopolymer chains (Mn approximately 1300 and 1500 g/mol, respectively) are incorporated into alternating lamellar layers of PS and PVP (total Mn approximately 196 500 g/mol). The location of the particles is controlled by varying the composition of ligands on the particle surfaces. In particular, gold particles coated with 100% PS or PVP reside near the center of the respective polymer domains, while particles coated with a mixture of both homopolymers reside at the interfaces between the two blocks.