(a) Which of the d-aldopentoses will give optically active aldaric acids on oxidation with HNO3 ?(b) Which of the d-aldotetroses will give optically active aldaric acids on oxidation with HNO3 ?(c) Sugar X is known to be a d-aldohexose. On oxidation with HNO3, X gives an optically inactive aldaric acid. WhenX is degraded to an aldopentose, oxidation of the aldopentose gives an optically active aldaric acid. Determine thestructure of X.(d) Even though sugar X gives an optically inactive aldaric acid, the pentose formed by degradation gives an opticallyactive aldaric acid. Does this finding contradict the principle that optically inactive reagents cannot form opticallyactive products?(e) Show what product results if the aldopentose formed from degradation of X is further degraded to an aldotetrose.Does HNO3 oxidize this aldotetrose to an optically active aldaric acid?
Carbohydrates
Carbohydrates are the organic compounds that are obtained in foods and living matters in the shape of sugars, cellulose, and starch. The general formula of carbohydrates is Cn(H2O)2. The ratio of H and O present in carbohydrates is identical to water.
Starch
Starch is a polysaccharide carbohydrate that belongs to the category of polysaccharide carbohydrates.
Mutarotation
The rotation of a particular structure of the chiral compound because of the epimerization is called mutarotation. It is the repercussion of the ring chain tautomerism. In terms of glucose, this can be defined as the modification in the equilibrium of the α- and β- glucose anomers upon its dissolution in the solvent water. This process is usually seen in the chemistry of carbohydrates.
L Sugar
A chemical compound that is represented with a molecular formula C6H12O6 is called L-(-) sugar. At the carbon’s 5th position, the hydroxyl group is placed to the compound’s left and therefore the sugar is represented as L(-)-sugar. It is capable of rotating the polarized light’s plane in the direction anticlockwise. L isomers are one of the 2 isomers formed by the configurational stereochemistry of the carbohydrates.
(a) Which of the d-aldopentoses will give optically active aldaric acids on oxidation with HNO3 ?
(b) Which of the d-aldotetroses will give optically active aldaric acids on oxidation with HNO3 ?
(c) Sugar X is known to be a d-aldohexose. On oxidation with HNO3, X gives an optically inactive aldaric acid. When
X is degraded to an aldopentose, oxidation of the aldopentose gives an optically active aldaric acid. Determine the
structure of X.
(d) Even though sugar X gives an optically inactive aldaric acid, the pentose formed by degradation gives an optically
active aldaric acid. Does this finding contradict the principle that optically inactive reagents cannot form optically
active products?
(e) Show what product results if the aldopentose formed from degradation of X is further degraded to an aldotetrose.
Does HNO3 oxidize this aldotetrose to an optically active aldaric acid?
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