Carbohydrate chemistry: synthetic and structural challenges towards the end of the 20th century

Carbohydrate chemistry has acquired considerable interest in many different facets during the last decades of the century. Particularly, the synthesis of complex carbohydrates in the form of large oligosaccharides has paved the way for a better appreciation of the function of carbohydrates in biological systems. The impressive advances associated with the structural determination and analysis of oligosaccharides has furthermore contributed to the increased focus on the role of carbohydrates particularly in the form of glycoproteins but also as signal molecules in general. The primary goal of this work is to discuss the advancement of structural assessment of large oligosaccharides as typi®ed by the structural determination of the 22-mer saccharide from the LPS of Salmonella enterica ssp. typhimurium strain 1135 using very high ®eld strength NMR spectroscopy. The challenges of synthesizing and analysing the structure of glycopeptides will also be discussed. Finally, the latest developments in glycopeptide libraries generated by solidphase combinatorial chemistry will be presented in addition to examples of new techniques where the increased sensitivity using nanoprobe technology in combination with MALDI-TOF MS spectroscopy was used in the structural assignment of such complex glycopeptides; a methodology of invaluable importance for the analysis of glycopeptides on single beads.