Properties of Carbohydrates

The reaction of phenylhydrazine, and particularly substituted phenylhydrazines, with the carbonyl group of sugars is extensively utilized in their identification. The derivatives are called osazones if two molecules of phenylhydrazine add to one molecule of sugar, as in the case of glucose, and phenylhydrazones when one molecule 

Prepare 5 ml of Pollen s reagent in accordance with directions given on pages 192-193, and test the reducing action of glucose. Record your observations. 

Place in separate tubes 5 ml of solutions or suspension of sucrose, starch and cellulose. Add 1 ml of dilute hydrochloric acid and heat in a water bath for one-half hour. Add a drop of phenolphthalein, and neutralize carefully with sodium hydroxide. Repeat the Feh-ling s solution test, using a few drops of the hydrolyzed solution. Write the equations for the hydrolysis which took place as determined by the tests. 

Caution Cellulose nitrate is very inflammable. Handle it with care. Do not leave any nitrocellulose in your drawer. It should be used as soon as it is prepared, and if any remains it should be disposed of according to directions of the instructor. 

Place a solution of nitrate and another of acetate on watch glasses and allow each to stand until all the solvent has evaporated. Pour water on the film, and after a few minutes remove it from the watch glass and allow it to dry. 

Heating a solution of hexoses in a strong non-oxidising acidic conditions, hydroxy methyl furfural is formed. The hydroxymethyl furfural from hexose is usually oxidized further to other products When phenolic compounds such as resorcinol, a-naphthol or enthrone are added, mixture of coloured compounds are formed.  

The molisch test used for detecting carbohydrate in solution is based on following principle. When cone. H2SO4 is added slowly to a carbohydrate solution containing a-naphthol, a pink colour is produced at the juncture. The heat generated during the reaction hydrolyse and dehydrate it to produce furfural or hydroxymethyl furfural which then react with a-naphthol to produce the pink colour. 

When sugars are treated with appropriate acid anhydride or acid chloride under proper conditions, the hydroxyl groups get esterified and form sugar esters. 

Identify the letter of the choice that best completes the statement or answers the question. 

Two sugars that differ in configuration only at one chiral center are called 

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R. Goldberg and J. Tewari, Thermodynamic and transport properties of carbohydrates and their monophosphates The pentoses and hexoses, J. Phys. Chem. Ref. Data, 18 (1989) 809-822. 

B. Friedman, K. Vaddi, C. Preston, E. Mahon, J. R. Cataldo, and J. M. A. McPherson, Comparison of the pharmacological properties of carbohydrate remodeled recombinant and placental-derived /i-Glucocerebrosidase Implications for clinical efficacy in treatment of Gaucher disease, Blood, 93 (1999) 2807-2816. 

Recent advances on the application of NMR methods to study the conformation and recognition properties of carbohydrates... 

In analyzing the conformational properties of carbohydrates, it has often been the practice to consider individual monomer rings to be rigid units, with the only molecular flexibility lying in torsional rotations about the linkage bonds. 

The plastics industry is but one outgrowth of our knowledge of organic chemistry. As we explore in the next chapter, our understanding of life itself is based on our understanding of the properties of carbohydrates, fats, proteins, and nucleic acids, all of which are polymers containing the functional groups introduced in this chapter. 

An understanding of stereochemistry is particularly important to understanding the properties of carbohydrates. Configurational and conformational isomerism play an important role. For this reason, you may wish to review Chapter 5 and Sections 12-3 and 19-5. 

Roebuck, B., Goldblith, S. and Westphal, W. 1972. Dielectric properties of carbohydrate-water mixtures at microwave frequencies. Journal of Food Science. 37 199-204. 

A. A. Gorkovenko, E. L. Berman, S. Y. Zaitsev, and V. A. Ponomarenko, Synthesis and surface-active properties of carbohydrate amphiphilic compounds and polymers based on them, Bull. Acad. Sci. USSR, Chem. Sci., 36 (1987) 2135-2139. 

R. J. Ferrier, Structure and chromatographic properties of carbohydrates. II. The liquid-liquid partition mobilities of aldono-y-lactones, J. Chromatogr., 9 (1962) 251-252. 

Goldberg and Tewari published an evaluation of thermodynamic and transport properties of carbohydrates and their monophosphates in 1989 and of the ATP series in 1991. Miller and Smith-Magowan published on the thermodynamics of the Krebs cycle and related compounds in 1990. 

In this experiment, you will investigate some chemical properties of carbohydrates in terms of their functional groups. 

Thermal Uses and Properties of Carbohydrates and Lignins Symposium", K.V. Sarkanen and D. Tillman, eds, Academic... 

Capon, B., and Overend, W. G., Constitution and Physicochemical Properties of Carbohydrates, 15, 11-51 Carr, C. Jelleff, and Krantz, John C., Jr., Metabolism of the Sugar Alcohols and Their Derivatives, 1, 175-192 Chizhov, O. S. See Kochetkov, N. K. Churms, Shirley C Gel Chromatography of Carbohydrates, 25, 13-51 Clamp, John R., Hough, L., Hickson, John L., and Whistler, Roy L Lactose, 16, 159-206 Compton, Jack, The Molecular Constitution of Cellulose, 3, 185-228 Conchie, J., Lewy, G. A., and Marsh,... 

Both Haworth and Hirst believed in team-work, and this was seen to advantage in the research that settled the notable controversy with C. S. Hudson over the structure of D-mannose. This was concluded at a famous meeting with Haworth, Hudson, and Purves in 1930, which was fully described by Hirst in The Hudson Memorial Lecture [/ Chem. Soc., 4042-4058 (1954)]. Hirst always had great admiration for Hudson s researches on the optical properties of carbohydrates, and conducted extensive personal experimental work (with C. E. Wood) on optical rotatory dispersion. 

K. Loos, G. Jonas, R. Stadler, Macromol. Chem. Phys. 2001,202,3210-3218, Carbohydrate Modified Polysiloxanes, 3. Solution Properties of carbohydrate-PolysUoxane conjugates in Toluene . 

F. Shalizadeh, K. V. Sarkanen, and D. A. Tillman (eds.). Thermal Uses and Properties of Carbohydrate and Lignins, Academic Press, New York, 1976 p. 217. 

Lactose, a carbohydrate formed from two simple sugars, glucose and galactose, is the principal sugar in dairy products. Many individuals, mainly of Asian and African descent, lack adequate amounts of the enzyme necessary to digest and absorb lactose. This condition, lactose intolerance, is associated with abdominal cramping and recurrent diarrhea, and is precipitated by the ingestion of milk and dairy products. In Chapter 27, we learn about the structure, synthesis, and properties of carbohydrates like lactose. 

A key related property of carbohydrates in their role as mediators of cellular interactions is the tremendous structural diversity possible within this class of molecules. Carbohydrates are built from monosaccharides, small molecules that typically contain from three to nine carbon atoms and vary in size and in the stereochemical configuration at one or more carbon centers. These monosaccharides may be linked together to form a large variety of oligosaccharide structures. The unraveling of these oligosaccharide structures, the discovery of their placement at specific sites within proteins, and the determination of their function are tremendous challenges in the field of proteomics. 

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