Classification of Monosaccharides

The nomenclature and classification of monosaccharides is further complicated by the presence of chiral carbons within monosaccharides. In the late nineteenth century it was ascertained that the configuration of the last chiral carbon in each of the naturally occurring monosaccharides is the same as that for (-i-)-glyceraldehyde. This configuration was designated as D and it was determined that all naturally occurring monosaccharides were in the D configuration. 

Classification of monosaccharides according to functional groups and carbon numbers... 

Most sugars have their own specific common names, such as glucose, fructose, galactose, and mannose. These names are not systematic, although there are simple ways to remember the common structures. We simplify the study of monosaccharides by grouping similar structures together. Three criteria guide the classification of monosaccharides ... 

Classification of monosaccharides is done by the number of carbon atoms and the types of functional groups. For example, glucose and fructose have the same chemical formula, but different structure glucose having an aldehyde (internal hydroxyl shown as -OH) and fructose having a keto group (internal double-bond O, shown as =0). 

The Latin word for sugar is saccharum and the derived term saccharide is the basis of a system of carbohydrate classification A monosaccharide is a simple carbohydrate one that on attempted hydrolysis is not cleaved to smaller carbohydrates Glucose (C6H12O6)... 

Classification of Carbohydrates 1102 23-3 Monosaccharides 1103 23-4 Erythro andThreo Diastereomers 1106 23-5 Epimers 1107... 

The classification of each of the following monosaccharides is given below the structure. 

EXAMPLE 11.3 The classification of each of the monosaccharides is given beneath its structure in Fig. 11-2. ... 

The Latin word for sugar is saccharum, and the derived term saccharide is the basis of a system of carbohydrate classification. A monosaccharide is a simple carbohydrate, one that on attempted hydrolysis is not cleaved to smaller carbohydrates. Glucose (C6H12O6), for example, is a monosaccharide. A disaccharide on hydrolysis is cleaved to two monosaccharides, which may be the same or different. Sucrose—common table sugar—is a disaccharide that yields one molecule of glucose and one of fructose on hydrolysis. 

Classification of the polysaccharide type is achieved fundamentally by hydrolysis to identifiable sugars, and by methylation analysis, in which the cleavage products from the permethylated polysaccharide are identified and assayed, after conversion to alditol acetates, acetylated aldononitriles, or other derivatives, by GC and GC-MS. Methanolysis of the permethylated polysaccharide and conversion to TMS derivatives is an alternative. The proportions of monosaccharides and their linkage modes are deduced from the molar quantities of sugar methyl ethers derived from the processed polysaccharide... 

The behavior of polysaccharides is also critically influenced by the nature of the substituent groups bound to the individual monosaccharides. These substituents can be of natural origin or they may be synthesized and thus of seminatural quality. Whether they are natural or seminatural, the classification of polysaccharides falls into one of five categories, based primarily on the polysaccharide charge. These include anionic, cationic, nonionic, amphoteric, and hydrophobic. 

Also see CARBOHYDRATE[S], Table C-6, Classification of Carbohydrates and section headed "Monosaccharides.")... 

The monosaccharides more commonly found in linear polysaccharides are shown in Fig. 1.1. With polysaccharides a classification of practically encountered covalent structures may be made using the following three main groups (Rees, 1977) a) periodic sequences, b) interrupted sequences, c) aperiodic sequences. 

Classification of the Carbohydrates.—A. Monosaccharides.—Simple sugars having the general formula C H2 0 . All are soluble in water, have a sweet taste, and reduce alkaline solutions of copper. 

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