The glacial landsystem of a tropical glacier: Charquini Sur, Bolivian Andes

International audienc

Solid phase peptide templated glycosidic bond formation

Glycosylation reactions performed between a glycosyl donor and acceptor covalently linked to a peptide template both in the solution and solid phase give similar yields and product distributions. The adoption of a solid phase approach opens the way for the synthesis of libraries of peptide templates in an attempt to screen for particular peptide sequences that effect complete regio-and stereochemical control during glycosidic bond formation, whilst the use of second generation donors allows the possibility of an iterative approach. © 2003 Elsevier Science Ltd. All rights reserved

Peptide templated glycosidic bond formation: a new strategy for oligosaccharide synthesis

Glycosidation reactions performed between glycosyl donors and accepters covalently linked to a peptide template produced increased regio- and stereo-selectivities, which were dependent on the nature of the peptide, and which may be rationalised by simple molecular modelling

Peptide templated glycosylation reactions

Glycosyl donors and acceptors may be covalently linked to aspartic acid residues via OH-6 esters. Peptide elaboration allows glycosylation reactions to be performed between donors and acceptors linked to this peptide template. These reactions display increased regio- and stereoselectivities, which are dependent on the nature of the peptide. Simple molecular modelling is used to rationalise the differing product distributions obtained by variation of the linking amino acid sequence. Copyright (C) 2000 Elsevier Science Ltd

Synthesis of fluorescence-labelled disaccharide substrates of glucosidase II.

The fluorescence-labelled disaccharides Glcalpha(1-->3)GlcalphaOR and Glcalpha(1-->3)ManalphaOR, both substrates for the glycoprotein-processing enzyme glucosidase II, were synthesised via the use of a n-pentenyl-derived linker at the anomeric position. This allowed incorporation of a pyrenebutyric acid label, via a sequence of oxidative hydroboration, mesylation, azide displacement, reduction with concomitant global deprotection, and peptide coupling. Selective activation of a fully armed thioglycoside in the presence of n-pentenyl glycosides was readily achieved by the use of methyl triflate as promoter

Carbopeptoids: peptides and diketopiperazines incorporating the anomeric centre of mannopyranose

An approach to the synthesis of D-mannopyranose derivatives incorporating an anomeric α-amino acid component is described. An N-acylated bicyclic [2.2.2] lactone, formed via an oxidative ring closure, provides access to a new class of glycopeptide analogues of D-mannopyranose and determines the anomeric configuration of compounds derived therefrom. The mannopyranose diketopiperazine may be equilibrated to the more stable furanose form under basic conditions; in general, mannopyranose derivatives containing an α-amino acid moiety at the anomeric position are less stable than the mannofuranose isomers