Acid-functionalized PVA composite membranes for pervaporation-assisted esterification.

Composite flat-sheet membranes functionalized with imidazolium-based ionic liquids (ILs) grafted to poly(vinyl alcohol)/glutaraldehyde as a catalytic layer were developed to enhance the esterification between -butanol and acetic acid. The functionalized membranes were produced dip-coating commercial pervaporation membranes, and two distinct Brønsted-acidic ILs with an imidazolium-based cation and different (hydrogen sulfate [HSO] or bromide [Br]) anions were compared. Compact, 12 μm-thick, defect-free catalytic layers were observed on top of the pervaporation membrane supports, and the determined penetration depth of the ILs confirmed their presence in the upper part of the coating.

Lanthanide(III) SMMs with cationic and anionic complex fragments formed by a Schiff base: structure, luminescence, magnetic properties and calculations.

The syntheses, structures, luminescence and magnetic properties of a new series of Ln(III) complexes of the formula [Ln(L)(HO)(DMF)][Ln(L)] (in which HL is ,'-ethylaminebis[1-phenyl-3-methyl-4-formylimino-2-pyrazoline-5-one]; Ln(III) - Gd (1), Tb (2), or Dy (3) ions). The crystal structures were determined by single-crystal X-ray diffraction measurements for all the above-mentioned complexes. The crystals of these compounds consist of cationic [Ln(L)(HO)(DMF)] and anionic [Ln(L)] moieties which form a 3D supramolecular architecture by the H-bonds and electrostatic forces.

Optimised production of technetium-94m for PET imaging by proton-irradiation of phosphomolybdic acid in cyclotron liquid target.

Natural-abundance phosphomolybdic acid (H(MoPO) ‧12HO, 0.181-0.552 g Mo/mL) solutions were irradiated with 12.

Colorful 3D Printing: A Critical Feasibility Analysis of Multi-Wavelength Additive Manufacturing.

Employing two colors of light to 3D print objects holds potential for accessing advanced printing modes, such as the generation of multi-material objects from a single print. Thus, dual-wavelength-driven photoreactive systems (reactions that require or utilize two wavelengths) and their exploitation as chemo-technological solutions for additive manufacturing technologies have experienced considerable development over the last few years. Such systems saw an increase in printing speeds, a decrease in resolution thresholds, and─perhaps most importantly─the actual generation of multi-material objects.

A biomimetic approach for the concise total synthesis of greenwaylactams A-C.

A concise, racemic total synthesis of three sesquiterpenoid alkaloids (greenwaylactams A-C) exhibiting an unprecedented 8-membered benzolactam is disclosed. Key transformations of this work include the ring expansion through cleavage of an indole Witkop oxidation, as well as an HFIP mediated cationic cyclisation to build up the pentacyclic carbon skeleton.

Photocatalytic Hydroalkylation of Aryl-Alkenes.

Here, we present a visible light-catalyzed hydroalkylation of aryl-alkenes affording C-C bonds using aryl-alkenes and alkyl iodides. We demonstrate the formation of various hydroalkylation products in excellent yields, with primary, secondary, and tertiary alkyl iodides being tolerated in the reaction. Mechanistic experiments reveal a pathway consisting of halogen atom transfer followed by a radical-polar crossover mechanism delivering the desired hydroalkylation products.

The In Vitro Cytotoxicity of oil and Its Components-Aromatic and Acyclic Monoterpene Alcohols.

The microscopic fungi and are known for their ability to synthetize essential oil, which has a composition similar to that of rose oil. The development of oil technology enables the production of rose-scented products, which are demanded by pharmaceutical, food, and perfumery industries. This study focuses on assessing the in vitro cytotoxicity of oil, in comparison with that of rose oil, using a combination of methods and two cell types (3T3 mouse fibroblast cell line and bone-marrow-derived mesenchymal stromal cells (BM-MSCs)).

Investigation of Leoligin Derivatives as NF-κΒ Inhibitory Agents.

The transcription factor NF-κB is an essential mediator of inflammation; thus, the identification of compounds that interfere with the NF-κB signaling pathway is an important topic. The natural products leoligin and 5-methoxyleoligin have served as a starting point for the development of NF-κB inhibitors. Using our modular total synthesis method of leoligin, modifications at two positions were undertaken and the effects of these modifications on the biological activity were investigated.

The application of bathophenanthroline for the determination of free iron in parallel with hROS in microdialysis samples.

Background: Free, non-protein bound, Fe(II), which can catalyse the formation of the toxic highly-reactive oxygen species (hROS), has been implicated in several neurodegenerative conditions. The determination of free Fe(II) and Fe(III) in samples obtained from microdialysis experiments has been limited by the small amounts of sample available.

New Method: This work describes the development of a HPLC, with absorbance detection, method, based on the complexation of Fe(II) with bathophenanthroline disulfonate (BS), which allows a complete extracellular iron analysis with the small sample amounts that are available from in vivo microdialysis in rat brain.

Structure and excitation-dependent emission of novel zinc complexes with pyridyltriazoles.

A series of Zn(ii) complexes with 5-(4--phenyl)-3-(pyridin-2-yl)-1,2,4-triazoles have been synthesized and subsequently characterized by single crystal X-ray diffraction, H-NMR, FT-IR spectroscopy, elemental analyses, ESI-MS, and PXRD. The X-ray diffraction analyses revealed that the complexes have a similar molecular structure and their supramolecular frameworks are constructed by hydrogen bonds and π⋯π interaction scaffolds. Upon irradiation with UV light, the studied complexes display deep blue emission at 396-436 nm in the solid state.

Impact of glutathione modulation on the toxicity of the Fusarium mycotoxins deoxynivalenol (DON), NX-3 and butenolide in human liver cells.

DON, NX-3 and butenolide (BUT) are secondary metabolites formed by Fusarium graminearum. Evidence for formation of DON-glutathione adducts exists in plants, and also in human liver (HepG2) cells mass spectrometric evidence for GSH-adduct formation was reported. NX-3 is a DON derivative lacking structural features for Thiol-Michael addition, while BUT has the structural requirements (conjugated double bond and keto group).

Continuous monitoring of highly reactive oxygen radicals during in vivo microdialysis.

Background: Terephthalate (TA(2-)), which reacts with highly reactive oxygen species (hROS) to form the fluorophor 2-hydroxy terephthalic acid (OH-TA) with a high selectivity, has been used for determining hROS formation during in vivo microdialysis. Previously this involved collecting fractions of the microdialysate and determining the OH-TA formed after HPLC (the batch method).

New Method: This work reports the development and validation of a procedure for continuously determining hROS formation during microdialysis.

9-(4-Bromo-phen-yl)-9H-carbazole.

In the title mol-ecule, C18H12BrN, the 4-bromo-phenyl ring is inclined to the mean plane of the carbazole moiety (r.m.s.

1-Nitro-9H-carbazole.

In the title mol-ecule, C12H8N2O2, the nitro group is tilted slightly with respect to the carbazole moiety [angle between the least-squares planes = 4.43 (9)°]. In the crystal, the mol-ecules are connected via pairs of N-H⋯O hydrogen bonds into dimers with -1 symmetry.

Baeyer-Villiger monooxygenases in aroma compound synthesis.

Baeyer-Villiger monooxygenases (BVMOs) are presented as highly selective and efficient biocatalysts for the synthesis of aroma lactones via kinetic resolution of 2-substituted cycloketones, exemplified with two δ-valerolactones, the jasmine lactones and their ε-caprolactone homologs. Analytical scale screens of our BVMO library ensued by preparative whole-cell biotransformations led to the identification of two enzymes (cyclohexanone monooxygenase from Arthrobacter BP2 and cyclododecanone monooxygenase from Rhodococcus SC1) perfectly suited for the task at hand: easily accessible racemic starting materials were bio-oxidized to almost enantiopure ketones and lactones in good yields (48-74%) and optical purities (ee 93% to >99%, E>100).

Highly reactive oxygen species: detection, formation, and possible functions.

The so-called reactive oxygen species (ROS) are defined as oxygen-containing species that are more reactive than O(2) itself, which include hydrogen peroxide and superoxide. Although these are quite stable, they may be converted in the presence of transition metal ions, such as Fe(II), to the highly reactive oxygen species (hROS). hROS may exist as free hydroxyl radicals (HO·), as bound ("crypto") radicals or as Fe(IV)-oxo (ferryl) species and the somewhat less reactive, non-radical species, singlet oxygen.

Application of continuous flow and alternative energy devices for 5-hydroxymethylfurfural production.

Dehydration of fructose and glucose in dipolar, aprotic solvents leads to formation of 5-hydroxymethylfurfural. Conditions for continuous flow reactions using a cartridge-based reactor system and a stop-flow microwave reactor were established showing very good product yields and selectivity without the limitation of a batch process such as upscaling and precise temperature monitoring and control. A maximum product HPLC yield of 90.

Facile, solvent and ligand free iron catalyzed direct functionalization of N-protected tetrahydroisoquinolines and isochroman.

An efficient method for an iron catalyzed oxidative indolation and methoxyphenylation of N-protected tetrahydroisoquinolines and isochroman is described including subsequent facile deprotection.

Mechanistic aspects of the Fenton reaction under conditions approximated to the extracellular fluid.

The Fenton reaction was investigated, in a medium approximating to that of the extracellular fluid (ECF), by rapid-mixing stopped flow experiments and HPLC analysis using sodium terephthalate (TA(2-)). The reactive intermediate of the Fenton reaction hydroxylates the essentially nonfluorescent, TA(2-) to the brilliant fluorophor 2-hydroxy-terephthalate (OH-TA), which allows the Fenton reaction to be monitored in stopped-flow experiments. There was no artefactual quenching of the fluorescence by substances present in the Fenton-reaction mixture or in the artificial cerebrospinal fluid (aCSF) that might have influenced OH-TA quantification.

The detection of hydroxyl radicals in vivo.

Several indirect methods have been developed for the detection and quantification of highly reactive oxygen species (hROS), which may exist either as free hydroxyl radicals, bound "crypto" radicals or Fe(IV)-oxo species, in vivo. This review discusses the strengths and weaknesses associated with those most commonly used, which determine the hydroxylation of salicylate or phenylalanine. Chemical as well as biological arguments indicate that neither the hydroxylation of salicylate nor that of phenylalanine can guarantee an accurate hydroxyl radical quantitation in vivo.

Validation of a robust and sensitive method for detecting hydroxyl radical formation together with evoked neurotransmitter release in brain microdialysis.

Sodium terephthalate was shown to be a new robust and sensitive chemical trap for highly reactive oxygen species (hROS), which lacks the drawbacks of the salicylic acid method. Reaction of the almost non-fluorescent terephthalate (TA2-) with hydroxyl radicals or ferryl-oxo species resulted in the stoichiometric formation of the brilliant fluorophor, 2-hydroxyterephthalate (OH-TA). Neither hydrogen peroxide nor superoxide reacts in this system.