New chalcone-3-O-glycoside derivatives: Synthesis and characterization

Seven novel carbohydrate conjugates of new chalcone-3- O-glycosides were synthesized and characterized. Starting from the substituted 3′-hydroxyarylmethylacetophenone derivatives (chalcones) with α-acetobromoglucose in anhydrous acetone were synthesized 2,3,4,6-tetra- O-acetyl-3′- O-β-d-glucopyranosyloxychalcones. Deblocking the latter with CH3ONa in dry methanol results in substituted chalcone-3- O-glycosides (3′- O-β-d-glucopyranosyloxychalcones). The structures of the newly synthesized chalcone-3- O-glycosides were characterized based on 1H nuclear magnetic resonance, 13C nuclear magnetic resonance, mass spectroscopy, and Fourier-transform infrared spectroscopy.

Covalent Immobilization of β-Glucosidase into Mesoporous Silica Nanoparticles from Anhydrous Acetone Enhances Its Catalytic Performance

An immobilization protocol of a model enzyme into silica nanoparticles was applied. This protocol exploited the use of the bifunctional molecule triethoxysilylpropylisocyanate (TEPI) for covalent binding through a linker of suitable length. The enzyme β-glucosidase (BG) was anchored onto wrinkled silica nanoparticles (WSNs). BG represents a bottleneck in the conversion of lignocellulosic biomass into biofuels through cellulose hydrolysis and fermentation. The key aspect of the procedure was the use of an organic solvent (anhydrous acetone) in which the enzyme was not soluble. This aimed to restrict its conformational changes and thus preserve its native structure. This approach led to a biocatalyst with improved thermal stability, characterized by high immobilization efficiency and yield. It was found that the apparent KM value was about half of that of the free enzyme. The Vmax was about the same than that of the free enzyme. The biocatalyst showed a high operational stability, losing only 30% of its activity after seven reuses.

The identification of acetylcholine and choline in oat seedlings by gas chromatography and nuclear magnetic resonance (NMR)

Four methods of isolation and purification of choline esters from green 7-day-old oat ( <em>Avena sativa</em> L. cv. Diadem) seedlings were tested The results showed that the best recovery of acetylcholine and choline from plant tissues was obtained using an extraction solution composed of 15% 1N formic acid and 85%, acetone followed by precipitation of both these substances with ammonium reineckate. The presence of acetylcholine and choline in the plant extracts was confirmed by nuclear magnetic resonance (NMR) and gas chromatography. In the case of gas chromatography, after isolation and purification of the studied compounds from the plant material, estrification of choline followed by N-demethylation of acetylcholine and estrified choline were performed The demethylation reaction was conducted in a reaction mixture of 50 mM sodium thiophenolate and 25 mM thiophenol in anhydrous acetone. After its completion, the mixture was removed with pentanone and the demethylated esters were extracted into chloroform.

Determination of Antimycin-A in Water by Liquid Chromatographic/Mass Spectrometry: Single-Laboratory Validation

An LC/MS method was developed and validated for the quantitative determination and confirmation of antimycin-A (ANT-A) in water from lakes or streams. Three different water sample volumes (25, 50, and 250 mL) were evaluated. ANT-A was stabilized in the field by immediately extracting it from water into anhydrous acetone using SPE. The stabilized concentrated samples were then transported to a laboratory and analyzed by LC/MS using negative electrospray ionization. The method was determined to have adequate accuracy (78 to 113% recovery), precision (0.77 to 7.5% RSD with samples ≥500 ng/L and 4.8 to 17% RSD with samples ≤100 ng/L), linearity, and robustness over an LOQ range from 8 to 51 600 ng/L.

Enhanced Performance of Thermomyces lanuginosus Lipase-Catalyzed Regioselective Acylation of 6-Azauridine by a Co-Solvent Approach

A comparative study was made of lipozyme TL IM-catalyzed regioselective acylation of 6-azauridine with vinyl palmitate for the preparation of the 5'-O-monoester in co-solvent mixtures and pure polar solvents. Among the solvent systems investigated, a co-solvent mixture of anhydrous acetone/isooctane was found to be the best reaction medium, in which Lipozyme TL IM also exhibited good thermal and operational stability. It was also found that the acylation was dependent on the hydrophobic solvent content. The most suitable co-solvent was anhydrous acetone/isooctane (90:10, v/v). Under the optimal conditions, the initial rate, substrate conversion and 5'-regioselectivity were 20.6 mM/h, 99.0% and 99%, respectively.

Use of Stored Pollen to Hybridize a Mandarin Hybrid and Citrus tachibana

Fresh pollen from Citrus tachibana Macf. was oven-dried (37C), freeze-dried, or placed into anhydrous acetone, and stored at -20C over silica gel. Pollen freeze-dried or stored in anhydrous acetone did not germinate 24 hours after treatment; oven-dried pollen germinated in 1 hour and was comparable to fresh pollen. Pollen that was oven-dried for 12 hours and stored for 1 year was used to pollinate a monoembryonic hybrid of `Temple' (origin unknown) × `Orlando' (C. paradisi Macf. `Duncan' ×C. reticulata Blanco `Dancy'). Glutamate-oxaloacetate transaminase (GOT) isozyme profiles verified progeny hybridity.

Notizen: Darstellung und Schwingungsspektrum von Hexaiodoiridat(III), Cs3[IrI6]/Preparation and Vibrational Spectrum of Hexaiodoiridate(III), Cs3[IrI6]

On tempering heterogeneous pellets of Cs3[IrBr6] and NaI at 160 °C for several days, Cs3[IrI6] is formed by solid state ligand exchange. Because of the slow diffusion rate of the halide ions within the NaI phase, the reaction has to be repeated several times in order to accomplish complete iodation. The embedding material is removed with anhydrous acetone or methanol. Cs3[IrI6] is very slightly soluble in water and immediately hydrolyzed. The IR bands and Raman lines are assigned according to point group Oh.