Chemical and Functional Properties of Food Saccharides

2
CONTENTS
© 2004 by CRC Press LLC
Structure and Reactivity of
Saccharides
Wies law
Szeja
2.1 Stereochemistry of Monosaccharides
2.2 The Complex Formation of Carbohydrates with Cations
2.3 Chemical Reactions of Saccharides
2.3.1 Reduction
2.3.2 Oxidation
2.3.3 Alkylation
2.3.4 Acylation
2.3.5 Glycosylation
2.3.6 Biological Significance of the Efficiency of O-Glycosylation
2.3.7 Reactions with Amino Compounds
References
2.1 STEREOCHEMISTRY OF MONOSACCHARIDES
The physical, biological, and chemical properties of organic compounds depend,
among other things, on the nature and steric arrangement of the chemical bonds.
Stereoisomeric hexoses, which differ in configuration of their molecules, are examples
of a relationship between three-dimensional structure and biological activity of compounds.
The free rotation around a single bond produces a different three-dimensional
arrangement of the atoms in space; that is, different molecule conformations. Conformations
rapidly convert into one another and are therefore nonseparable. In a vast
majority of compounds with an alicyclic six-membered ring, the molecules, in most
cases, take the chair conformation. One bond on each carbon atom is directed perpendicularly
to the plane of the ring (axially) and the other resides in the plane of
the ring (the equatorial bond), denoted in (2.1) as a and e, respectively.
a
e
e
a
O
e a
e
e
a
a
2.1