Monosaccharides, definition

In the course of the study, we found that a family of monosaccharides exhibited a definite adsoi ption selectivity (Langmuir s isotherm adsoi ption constant), reflecting their molecular stmctures. 

The present Recommendations deal with the acyclic and cyclic forms of monosaccharides and their simple derivatives, as well as with the nomenclature of oligosaccharides and polysaccharides. They are additional to the Definitive Rules for the Nomenclature of Organic Chemistry [13,14] and are intended to govern those aspects of the nomenclature of carbohydrates not covered by those rules. 

Fischer projections are however, unsatisfactory when considering the physical properties and chemical reactivity of monosaccharides for which definitive spatial formulations are necessary. These are given below for D-glyceraldehyde, D-erythrose and D-threose, for which the (/ ,S configuration may be readily assigned at the appropriate chiral carbons. 

Early studies employing hydrogen chloride as catalyst on perbenzoylated sugars showed complicated product mixtures [1,30], while Lewis acid-catalyzed mercaptolysis of peracetylated monosaccharides afforded the corresponding thioglycosides in good yields [31,32,33], However, from a preparative point of view (smell, work-up), the present use of a solvent and only a small excess of thiol is definitely an advantage. 

Complexes of Cr111 with ascorbate, which are likely to form during the reactions of Crvl with this major intracellular reductant, have been studied (mainly by Cieslak-Golonka and co-workers),1062-1064 but no definitive structural information has been obtained to date. Partially characterized Crm complexes with monosaccharides or their oxidized derivatives (e.g., aldonic acid) have been isolated from the reactions with either Cr1111092 or CrVI.1093,1094... 

The prefixes D- and L- found in the complete name of a monosaccharide are used to identify one of two possible isomeric forms called stereoisomers. By definition, each member of a pair of stereoisomers must have the same molecular formula and the same bonding. How then do isomers of the D-family differ from those of the L-family D- and L-isomers differ in the spatial arrangements of atoms in the molecule. 

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