Concept explainers
Interpretation:
The structure of the key intermediate when
Concept introduction:
Disaccharides are carbohydrates that yield two monosaccharide molecules on hydrolysis.
Disaccharides are glycosides in which the alkoxy group attached to the anomeric carbon atom is derived from a second sugar molecule.
Maltose is made up from hydrolysis of starch.
In maltose, two
The linkage in maltose is called
The change from one anomeric form to the equilibrium mixture is accompanied by a change in optical rotation is termed as mutarotation.
Diasaccharides undergo mutarotation when dissolved in water.
The mutarotation is a slow process in aqueous solutions but can be catalyzed by either acid or base.
A base abstracts an acidic proton in the given structure.
The flow of electrons in the mechanism is shown by the curved arrows.
The open chain form of the sugar is the key intermediate in the mutarotation of disaccharides.
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EBK ORGANIC CHEMISTRY
- Aldohexoses A and B are formed from aldopentose C via a Kiliani–Fischer synthesis. Nitric acid oxidizes A to an optically active aldaric acid, B to an optically inactive aldaric acid, and C to an optically active aldaric acid. Wohl degradation of C forms D, which is oxidized by nitric acid to an optically active aldaric acid. Wohl degradation of D forms (+)-glyceraldehyde. Identify A, B, C, and D.arrow_forwardTreatment with sodium borohydride converts aldose A to an optically inactive alditol. Wohl degradation of A forms B, whose alditol is optically inactive. Wohl degradation of B forms d-glyceraldehyde. Identify A and B.arrow_forwardSugar 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 Xarrow_forward
- If lactose is first hydrolyzed (by addition of sulfuric acid) into its constituent monosaccharide, and then subjected to complete methylation, what methylated products do you expect?arrow_forwardA D-aldohexose A is formed from an aldopentose B by the Kiliani–Fischer synthesis. Reduction of A with NaBH4 forms an optically inactive alditol. Oxidation of B forms an optically active aldaric acid. What are the structures of A and B?arrow_forwardA D-aldopentose A is reduced to an optically active alditol. Upon Kiliani–Fischer synthesis, A is converted to two D-aldohexoses, B and C. B is oxidized to an optically inactive aldaric acid. C is oxidized to an optically active aldaric acid. What are the structures of A–C?arrow_forward
- Macroscale and Microscale Organic ExperimentsChemistryISBN:9781305577190Author:Kenneth L. Williamson, Katherine M. MastersPublisher:Brooks Cole