Concept explainers
Interpretation:
The Fischer projection formulas for the given compounds, using given data are to be written.
Concept Introduction:
▸ Oxidation of aldoses by nitric acid produces optically inactive aldaric acids. This is due to the formation of meso compounds. Compounds that do not form meso structures are optically active.
▸ The Fischer projection is a way of representing
▸ The Ruff degradation reaction is used for decreasing the number of carbon atoms of the respective aldoses, thereby, shortening the carbon chain of the compound. It works in two steps: 1) Using bromine water to oxidize an aldose to the respective aldonic acid and, 2) using
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Organic Chemistry
- An unknown reducing disaccharide is found to be unaffected by invertase enzymes. Treatment with an a@galactosidasecleaves the disaccharide to give one molecule of d-fructose and one molecule of d-galactose. When the disaccharideis treated with excess iodomethane and silver oxide and then hydrolyzed in dilute acid, the products are2,3,4,6-tetra-O-methylgalactose and 1,3,4-tri-O-methylfructose. Propose a structure for this disaccharide, and give itscomplete systematic name.arrow_forwardTrehalose, C12H22O11, is a nonreducing sugar that is only 45% as sweet as sugar. When hydrolyzed by aqueous acid or the enzyme maltase, it forms only d-glucose. When it is treated with excess methyl iodide in the presence of Ag2O and then hydrolyzed with water under acidic conditions, only 2,3,4,6-tetra-O-methyl-d-glucose is formed. Draw the structure of trehalosearrow_forwardd-Xylose and d-lyxose are formed when d-threose undergoes a Kiliani–Fischer synthesis. d-Xylose is oxidized to an optically inactive aldaric acid,whereas d-lyxose forms an optically active aldaric acid. What are the structures of d-xylose and d-lyxose?arrow_forward
- Raffinose is a trisaccharide (C18H32O16) isolated from cottonseed meal. Raffinose doesnot reduce Tollens reagent, and it does not mutarotate. Complete hydrolysis of raffinosegives d-glucose, d-fructose, and d-galactose. When raffinose is treated with invertase,the products are d-fructose and a reducing disaccharide called melibiose. Raffinose isunaffected by treatment with a b@galactosidase, but an a@galactosidase hydrolyzes itto d-galactose and sucrose. When raffinose is treated with dimethyl sulfate and basefollowed by hydrolysis, the products are 2,3,4-tri-O-methylglucose, 1,3,4,6-tetraO-methylfructose, and 2,3,4,6-tetra-O-methylgalactose. Determine the completestructures of raffinose and melibiose, and give a systematic name for melibiose.arrow_forwardAldohexoses 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_forwardA reddish color is obtained when compound A (a disaccharide) is reacted with Benedict solution. Is this compound more likely maltose or sucrosearrow_forward
- Aldohexoses A and B both undergo Ruff degradation to give aldopentose C. On treatment with warm nitric acid, aldopentose C gives an optically active aldaric acid. B alsoreacts with warm nitric acid to give an optically active aldaric acid, but A reacts to givean optically inactive aldaric acid. Aldopentose C is degraded to aldotetrose D, whichgives optically active tartaric acid when it is treated with nitric acid. Aldotetrose D isdegraded to (+)@glyceraldehyde. Deduce the structures of sugars A, B, C, and D, and useFigure 23-3 to determine the correct names of these sugars.arrow_forwardTwo sugars, A and B, are known to be glucose and galactose, but it is not certain which oneis which. On treatment with nitric acid, A gives an optically inactive aldaric acid, whileB gives an optically active aldaric acid. Which sugar is glucose, and which is galactose?arrow_forwardMonosaccharide Structure and Stereochemistry For D-arabinose: Draw its enantiomer.arrow_forward
- Chemistry for Today: General, Organic, and Bioche...ChemistryISBN:9781305960060Author:Spencer L. Seager, Michael R. Slabaugh, Maren S. HansenPublisher:Cengage Learning