Silver Acetate Catalyzed Hydroamination of 1-(2-(Sulfonylamino)phenyl)prop-2-yn-1-ols to (Z)-2-Methylene-1-sulfonylindolin-3-ols

A method to prepare (Z)-2-methylene-1-sulfonylindolin-3-ols efficiently that relies on silver acetate catalyzed hydroamination of 1-(2-(sulfonylamino)phenyl)prop-2-yn-1-ols is reported. The reactions proceed rapidly at room temperature with catalyst loadings as low as 1 mol % under conditions that did not require the exclusion of air or moisture. The utility of this N-heterocyclic ring-forming strategy as a synthetic tool that makes use of unsaturated alcohols was exemplified by the conversion of the (Z)-2-methylene-1-sulfonylindolin-3-ol to examples of other members of the indole family of compounds.     

Development of a biodegradable, temperature-sensitive dextran-based polymer as a cell-detaching substrate

A biodegradable, temperature‐sensitive dextran‐allyl isocyanate‐ethylamine (TSDAIE) as a nonenzymatic cell detachment polymeric substrate for human endothelial progenitor cells (EPCs) is developed and examined. The lower critical solution temperature of TSDAIE is determined; its phase transition occurrs at 18 to 22 °C. For EPC culture, cell culture flasks are coated with TSDAIE and type I collagen. The TSDAIE coating enables EPC detachment when the culture is cooled to 4 °C. The concentration of TSDAIE affects EPC attachment, which is thereby used to optimize the concentration of TSDAIE for coating. At the determined optimal concentration, TSDAIE is found to be compatible for use in EPC culture as revealed by cell attachment, spreading, proliferation, and phenotype. Overall, biodegradable TSDAIE shows promise for applications that culture and expand EPCs including vascular regenerative medicine and tissue engineering.

     

Quantification of rosiglitazone in rat plasma and tissues via LC–MS/MS: Method development,validation, and application in pharmacokinetic and tissue distribution studies

A bioanalytical method for the quantification of rosiglitazone in rat plasma and tissues (adipose tissue, heart, brain, bone, and kidney) using LC–MS/MS was developed and validated. Chromatographic separation was achieved on a Gemini C₁₈ column (50 × 4.6 mm, 3 μm) using a mobile phase consisting of 10 mM ammonium formate (pH 4.0) and acetonitrile (10:90, v/v) at a flow rate of 0.8 mL/min and injection volume of 10 μL (internal standard: pioglitazone). LC–MS detection was performed with multiple reaction monitoring mode using target ions at m/z → 358.0 and m/z → 357.67 for rosiglitazone and pioglitazone (internal standard), respectively. The calibration curve showed a good correlation coefficient (r²) over the concentration range of 1–10,000 ng/mL. The mean percentage recoveries of rosiglitazone were found to be over the range of 92.54–96.64%, with detection and lower quantification limit of 0.6 and 1.0 ng/mL, respectively. The developed method was validated per U.S. Food and Drug Administration guidelines and successfully utilized to measure rosiglitazone in plasma and tissue samples. Further, the developed method can be utilized for validating specific organ-targeting delivery systems of rosiglitazone in addition to conventional dosage forms.     

Hydrophilic modification of polypropylene ultrafiltration membrane by air‐assisted polydopamine coating

Coating by a mussel inspired polydopamine (PDA) is a simple and promising strategy to modify the hydrophilicity of polymer membrane surfaces. In this work, PDA coating was used to modify polypropylene (PP) ultrafiltration hollow fiber membrane. PDA coating parameters, ie, solution concentration and coating time were varied, and the effect of those parameters on membrane morphology, porosity, water contact angle, and pure water flux was investigated. In addition, air‐assisted PDA coating process was also conducted by channelling the air through PP membrane to avoid pore blocking and prevent water flux decline. The results showed that PDA coating successfully improved the hydrophilicity of PP membrane indicated by the decrease of water contact angle from 110° to 67° after coated by 3 g/L of PDA solution for 3 hours. The addition of air permeation on membrane lumen also increased pure water flux up to 511.2 L/m².h, a 270% increase from unmodified PP membrane. It might be associated to the pore blocking prevention that has been proven by SEM image and the membrane porosity that was increased about 4%.     

Mesoporous Manganese Oxide/Lignin-Derived Carbon for High Performance of Supercapacitor Electrodes

This study explores the modification of lignin with surfactants, which can be used as a template to make mesoporous structures, and can also be used in combination with manganese oxide to produce manganese oxide/lignin-derived carbon. Organosolv extraction, using ethanol (70%) at 150 °C, was carried out to extract lignin from oil palm wood. Lignin was then mixed with Pluronic F-127, with and without Mn(NO₃)₂, and then crosslinked with acidic formaldehyde, resulting in a carbon precursor-based modified lignin. Carbonization was carried out at 900 °C to produce lignin-derived carbon and manganese oxide/lignin-derived carbon. The characterization materials included Fourier transform infrared (FTIR) spectroscopy, scanning electron microscope-energy dispersive X-ray (SEM-EDX) mapping, X-ray diffraction (XRD), and N₂-sorption analysis. FTIR curves displayed the vibration bands of lignin and manganese oxide. SEM images exhibited the different morphological characteristics of carbon from LS120% (lignin with a Pluronic surfactant of 120%) and LS120%Mn20% (lignin with a Pluronic of 120% and Mn oxide of 20%). Carbon LS120% (C-LS120%) showed the highest specific surface area of 1425 m²/g with a mean pore size of 3.14 nm. The largest mean pore size of 5.23 nm with a specific surface area of 922 m²/g was exhibited by carbon LS120%-Mn20% (C-LS120%-Mn20%). C-LS120%Mn20% features two phases of Mn oxide crystals. The highest specific capacitance of 345 F/g was exhibited by C-LS120%-Mn20%.     

Particle size distribution in mini-emulsion polymerization

The particle size distribution polydispersities of a number of macro- and mini-emulsion latexes are reported. In cases where the macro-emulsion and mini-emulsions were produced under very nearly identical conditions, the mini-emulsion will have a polydispersity equal to, or only very slightly greater than, the equivalent macro-emulsion. To cite this article: K. Landfester et al., C. R. Chimie 6 (2003).     

Crosslinked poly(ethylene oxide) fouling resistant coating materials for oil/water separation

Potential fouling reducing coating materials were synthesized via free-radical photopolymerization of aqueous solutions of poly(ethylene glycol) diacrylate (PEGDA). Crosslinked PEGDA (XLPEGDA) exhibited high water permeability and good fouling resistance to oil/water mixtures. Water permeability increased strongly with increasing the water content in the prepolymerization water mixture, going from 10 to 150 L μm/(m² h bar) as prepolymerization water content increased from 60 to 80 wt.%. However, molecular weight cutoff decreased as water content increased. These materials were applied to polysulfone (PSF) UF membranes to form coatings on the surface of the PSF membranes. Oil/water crossflow filtration experiments showed that the coated PSF membranes had water flux values 400% higher than that of an uncoated PSF membrane after 24 h of operation, and the coated membranes had higher organic rejection than the uncoated membranes.     

One-pot synthesis of multicomponent pyrazole-4-carbonitrile derivatives under solvent-free condition by using engineered polyvinyl alcohol catalyst

Heterocyclic chemistry has fascinated the researchers owing to its wide range of applications in various chemical fields. With this perspective, herein we present an environmentally benign procedure for the synthesis of pyrazole and its derivatives through multicomponent reaction by using SPVA as a heterogeneous acid catalyst. The synthesis protocol of SPVA catalyst includes functionalization of polyvinyl alcohol by sulfonic acid groups. The synthesized SPVA catalyst was then subjected to several characterization techniques to confirm its formation and study its physicochemical properties. The SPVA catalyst was then tested for its activity toward a multicomponent reaction of aromatic aldehyde, malononitrile and phenyl hydrazine. The SPVA catalyst with sufficient acidic sites displayed appreciable catalytic performance yielding 89% of the desired pyrazole product under ambient reaction conditions. The SPVA catalyst showed recyclability up to the sixth cycle without considerable loss in its activity. Furthermore, we made an effort to demonstrate the plausible mechanistic pathway for the SPVA-catalyzed pyrazole synthesis reaction. Interestingly, the present synthetic approach could effectively produce pyrazole products with high yields in the absence of base and solvent and in short reaction time making it a green and sustainable process.

Graphic abstract

     

Reconstructing the differentiation niche of embryonic stem cells using biomaterials

The biochemical cues and topographical architecture of the extracellular environment extensively influence ES cell fate. The microenvironment surrounding the developing embryo presents these instructive cues in a complex and interactive manner in order to guide cell fate decisions. Current stem cell research aims to reconstruct this multifaceted embryonic niche to recapitulate development in vitro. This review focuses on 2D and 3D differentiation niches created from natural and synthetic biomaterials to guide the differentiation of ES cells toward specific lineages. Biomaterials engineered to present specific physical constraints are also reviewed for their role in differentiation.