ABSTRACT
Monosaccharides are the basic structural units or building blocks of oligo- and poly-saccharides. This chapter deals with the conformation of pyranoside monosaccharides which are their repeating motifs. Monosaccharide residues which constitute the backbone of polysaccharide chains generally exist in the chair conformation. From 1947 onwards, there have been several attempts to analyze the ring conformation of pyranose sugars and their derivatives. The O. Hassel and B. Ottar scheme was the first such attempt. This postulates that the ring conformation which places the axially oriented hydroxymethyl and hydroxyl groups on the same side of the ring is unstable. Barker and Shaw studied the relative stabilities of the two chair conformations of the pyranose ring by computing the total amount of overlap of nonbonded atoms; overlap between each pair of atoms being calculated separately and added together. Favored conformations and structural features of monosaccharides gleaned from coupling constants in solution and conformational energy calculations are subsequently presented.
