Glycan analysis via derivatization with a fluorogenic pyrylium dye.

The expansion of glycomics analysis is reliant upon the development of robust, routine methods for carbohydrate characterization. Simple protocols to derivatize sugars with functionality that facilitate analysis-chromophores, fluorophores, charges, ionizable groups-are therefore necessary. Here we describe a method for the labeling of oligosaccharide mixtures with a fluorogenic pyrylium dye to enable analysis by capillary electrophoresis (CE) and matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF-MS).

Studies directed to understanding the structure of chitosan-metal complexes: investigations of mono- and disaccharide models with platinum(II) group metals.

X-ray and NMR experiments were performed with simple chitosan models based on glucosamine monosaccharides and disaccharides to understand the binding properties and structures of the complexes formed between this polysaccharide and platinum(II) metals. Subjection of the glucosamine derivatives with [PdCl2(PhCN)2] provided trans-diamine complexes which upon further treatment with excess (NH4)PF6 generated complexes possessing two 5-membered chelate rings involving the C2-amine and the C3-hydroxyl group of the two individual glucosamine units.

Creating carbon-carbon bonds with samarium diiodide for the synthesis of modified amino acids and peptides.

In this perspective, an overview of our experiences on the application of samarium diiodide in organic synthesis for the preparation of amino acid and peptide analogues is presented. Three different carbon-carbon bond forming reactions are discussed, including side chain introductions, gamma-amino acid synthesis and acyl-like radical additions for the construction of C-C mimics of the peptidic bonds.

Radical addition of nitrones to acrylates mediated by SmI2: asymmetric synthesis of gamma-amino acids employing carbohydrate-based chiral auxiliaries.

Alkyl nitrones possessing N-substituted sugars as chiral auxiliaries were found to effectively undergo an SmI(2)-mediated radical addition to n-butyl acrylate affording gamma-amino acid derivatives with high diastereomeric control.