Search results for "Anomer"

Crystal structure of 4,6-O-ethylidene-N-(2-hydroxybenzylidene)-β-D-glucopyranosylamine

2002

4,6-O-Ethylidene-N-(2-hydroxybenzylidene)-β-D-glucopyranosylamine was synthesized and characterized using analytical, spectral and single-crystal X-ray diffraction methods. The anomeric nature of the saccharide moiety was proposed based on 1H NMR studies and was confirmed by the crystal structure. The lattice structure of this compound was compared with that of its analogues.

Highly regioselective synthesis of a 3-O-sulfonated arabino Lewisa asparagine building block suitable for glycopeptide synthesis

2006

Using the stannylene method, the trisaccharide 2-acetamido-3-O-[6-O-benzyl-beta-D-galactopyranosyl]-4-O-[2,3,4-tri-O-benzyl-beta-D-arabinopyranosyl]-6-O-benzyl-2-deoxy-beta-D-glucopyranosyl azide was regioselectively sulfonated and, after reduction of the anomeric azide, coupled to Fmoc alpha-allyl aspartate. After Pd(0)-catalyzed deallylation, the sulfatyl Lewis(a) asparagine building block was obtained, suitable for solid-phase glycopeptide synthesis applying the fluoride labile PTMSEL linker system.

Organomercury(II) and organothallium(III) complexes with Cis-1,2-dicyanoethylenedithiolate ion

1977

Determination of organic and inorganic mercury species in water and sediment samples by HPLC on-line coupled with ICP-MS.

2009

This paper describes a preconcentration method for Hg(2+) and MeHg(+) in water samples using sodium diethyldithiocarbamate immobilized in polyurethane foam (PU-NaDDC) and an extraction method for several mercury species in sediment samples, including MeHg(+), EtHg(+) and PhHg(+), which is simple, rapid, and uses a single organic solvent. Separation and measurement were done by high-performance liquid chromatography on-line with inductively coupled plasma mass spectrometry (HPLC/ICP-MS). Initially, the test of recovery was applied using procedures compatible with HPLC. Under the optimum extraction conditions, recoveries of 96.7, 96.3 and 97.3% were obtained for MeHg(+), EtHg(+), and PhHg(+),…

Ultrasonographic mound height as predictor of vesicoureteral reflux resolution after endoscopic treatment in children

2016

Purpose: Endoscopic dextranomer/hyaluronic acid copolymer (Dx/HA) injection is a safe and efficacious treatment option for vesicoureteral reflux (VUR) in children. Endoscopic appearance, hydrodistention and amount of injected Dx/HA have been demonstrated not to be reliable predictors of outcome. Aim of this study was to evaluate Dx/HA mounds on ultrasound scans (US) and find out any eventual correlation with reflux resolution. Methods: We selected patients treated with endoscopic injection for moderate to high VUR, renal scaring or repeated infections under antibiotic prophylaxis. Success was defined by absence of VUR at control 3. months after surgery; at 3. months we also measured mound h…

Organomercury(II) derivatives of 2-thiouracil. An infrared and proton magnetic resonance study of structures

1983

Abstract The novel complexes RHg(s2UraH−1) (R = Me, Ph) where s2UraH−1 is the monoanion of 2-thiouracil, have been synthesized. Comparison of the infrared spectra of the solid complexes and of 1H nuclear magnetic resonance spectra of the complexes in dimethyl-d6 sulfoxide with spectra of s2 Ura and Na[s2UraH−1] allows the recognition of the existence of isomers in the solid, with bonding to exocyclic sulfur and to pyrimidine nitrogens. In solution, a simpler pattern is observed, with 2J(1H199Hg) indicating bonding to sulfur only.

N-Glycosyl Amides as Glycosyl Donors in Stereoselective Glycosylation Reactions

2004

Due to their high stability, N-glycosyl amides have so far not been considered as glycosyl donors for glycosylation reactions. Two new procedures for the cleavage of the anomeric amide functionality under mild reaction conditions and further stereoselective in situ conversions of the activated glycosyl donors with alcohols and amines to give β-configured O- and N-glycosides are described in this article.

N-Glycosylamines of 4,6-O-ethylidene-alpha-D-glucopyranose: synthesis, characterisation and structure of CO2H, Cl and F ortho-substituted phenyl deri…

2000

A saccharide based ligand suitable for metal binding (HLCOOH) has been synthesized using 4,6-O-ethylidene-alpha-D-glucopyranose (4,6-O-EGP) and anthranilic acid. A few analogous glycosylamines with chloro and fluoro ortho substitutions have also been synthesized and characterised. Complexes of HLCOOH with Na+, K+, Mg2+, Ca2+, Ba2+, Cd2+ and Hg2+ have been isolated and characterised fully. The crystal structures of 4,6-O-EGP, the chloro analogue of HLCOOH and the K+ complex of L-COOH are established. The anomeric nature, orientation of the binding core and the co-ordination aspects of K+ have been derived from these structures.

N-Glycosyl Amides: Removal of the Anomeric Protecting Group and Conversion into Glycosyl Donors.

2003

Organic derivatives of mercury and tin as promoters of membrane lipid peroxidation.

2008

The toxicity mechanisms of mercury and tin organic derivatives are still under debate. Generally the presence of organic moieties in their molecules makes these compounds lipophilic and membrane active species. The recent results suggest that Hg and Sn compounds deplete HS-groups in proteins, glutathione and glutathione-dependent enzymatic systems; this process also results in the production of reactive oxygen species (ROS), the enhancement of membrane lipids peroxidation and damage of the antioxidative defence system. The goal of this review is to present recent results in the studies oriented towards the role of organomercury and organotin compounds in the xenobiotic-mediated enhancement …