The synthesis of S- and O-glycosides of aliphatic and aromatic thiols, halohidrines and mercaptotriazoles, which in PTC conditions exhibit thiol-thione echilibrium, are presented. The yields of the glycosilation reactions in PTC conditions (47-78%) are comparable with those of reactions using Lewis Acid as promoters. The synthesised S- and O-glycosides have been characterized by Electronic Impact-Mass Spectroscopy (EI-MS), 1H-MNR spectroscopy and

The synthesis of some new trisazo direct dyes containing 4,4'diaminobenzanilide as middle component is presented. The coupling components were salicylic acid and two monoazo compounds synthesized by the acid coupling of the diazonium salt of the 5-nitroantranilic acid with 2-amino-5-hydroxy-7-naphtalene sulfonic acid and with 1-amino-8-maphthol-3,5-disulphonic acid.The dyes were analyzed by thin layer chromatography (TLC), alectronic spectra (VIS)and

Chondroitin/dermatan sulfate (CS/DS) chain of decorin (DCN) from human skin fibroblasts (HSk) was released by reductive β-elimination reaction and digested with chondroitin AC I lyase. Enzymatic hydrolysis mixture of CS/DS chains was separated by size-exclusion chromatography (SEC). Collected octasaccharide fraction was subjected to fully automated chip-based nanoelectrospray (nanoESI) quadrupole time-of-flight (QTOF) MS and tandem MS (MS/MS). MS

Gangliosides, sialic-acid-containing glycosphingolipids are involved in numerous biological processes and play essential roles in severe pathologies, with predilection in those of the central nervous system. Formerly, ganglioside composition and quantity were assessed exclusively by thin-layer chromatographic (TLC), immunochemical, and immunohistochemical methods, which have limited effectiveness being unable to detect minor components in mixtures

The dibenzo[a,d]cycloheptene skeleton is of importance taking into account the presence of this moiety in different compounds having theoretical or practical interest. A key intermediate in the synthesis of such compounds is 10,11- dihydro-5H-dibenzo[a,d]cyclohepten-5-one. The study of the MS fragmentation of this ketone may give information about the possible fragmentation of similar compounds. The central seven-member ring leads to a different

Geometry, electronic structure and energetic calculations were performed with semiempiric and ab initio methods of the Hyperchem package for ML2 and M2+L2 complexes possibly implied in ionic bridges mediating glycan-glycan interactions (M: Ca2+ and Mg2+, L: acetate, methylsulphate, etandiol, 1,4-dioxane). Calculated dissociation energies, in vacuum, for ML2 complexes with anions as ligands are in the range of 400-600 kcal/mol and 150-300 kcal/mol

Using the AM1 semiempirical MO method a conformational search study was performed for the conformers of the (3S,5R,6R)-6-acetylamidopenicillanic acid. The AM1 method gives 8 distinct conformers. The difference between the heat of formation of the minimum energy conformer and the one of the highest energy conformer is of 7.12 kcal/mol. The AM1 calculated bond lengths and angles for the minimum energy conformer are close to the experimentally determined

A conformational analysis with the PM3 semiempirical MO method was performed for the (3S,5R,6R)-6- acetylamidopenicillanic acid. Because the N atom of the exocyclic amidic group is pyramidalized by the PM3 method, a larger number of conformers (47) than the number of theoretically possible conformers have been obtained. The conformer that fit the best with the experimental geometry was not the lowest energy conformer, but the fourth conformer in

In this work is presented the synthesis of the first S-riboside using 1H-3-(4-ethoxy-phenyl)-5-mercapto- 1,2,4-triazole as aglycone, in the Ferrier reaction conditions. The 1N-, 4N-glycosilated derivatives were not observed during the reaction. The synthetised compounds were characterised by MS-EI,1H-NMR,I.R.,UV and melting points.

Mass spectrometry (MS) was introduced into clinical laboratories, and first applied to the evaluation of children at risk of inborn errors of metabolism. For the analysis of macromolecules and in particular for proteins, glycoconjugates and polynucleotides, a major milestone was achieved with the development in 1987 of matrix assisted laser desorption ionization by Karas and Hillenkamp and in 1988 of electrospray ionization by J. Fenn. Over the past