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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Chapter 22 Solutions
ORGANIC CHEMISTRY (LL) W/WILEYPLUS NEXT
- d-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_forwardDraw the structure of: (a) a polysaccharide formed by joining D-mannose units in 1->4-ß-glycosidic linkages; (b) a polysaccharide formed by joining D-glucose units in 1->6-a-glycosidic linkages. The polysaccharide in (b) is dextran, a component of dental plaque.arrow_forwardLactose is a disaccharide in which a glycosidic linkage connects the monosaccharides galactose and glucose. OH НО OH (a) Identify the glycosidic linkage and the acetal carbon in lactose. (b) What type of glycosidic linkage does lactose have (i.e., is it 1,1'-, 1,2'-, etc., and is it a or B)? (c) People who are lactose intolerant are deficient in the enzyme lactase, and therefore cannot efficiently break down the disaccharide into its monosaccharides. When lactose is treated with aqueous acid, however, this hydrolysis can take place, though relatively slowly. Draw the complete, detailed mechanism and the products of the acid-catalyzed hydrolysis of lactose. Но ОН НО ОН ОН Lactosearrow_forward
- A reddish color is obtained when compound A (a disaccharide) is reacted with Benedict solution. Is this compound more likely maltose or sucrosearrow_forwardWhich of the following statements is not true about glucose? (i) It is an aldohexose. (ii) On heating with HI it forms n-hexanearrow_forwardWhich statement about saccharides is correct? (A). Alpha anomers are more common than beta anoomers. (B). Two monosaccharides can form a disaccharide and oxygen. (C). Polysaccharides with alpha or beta glycosidic linkages have the different properties. (D). Disaccharides can be cyclic or acyclic.arrow_forward
- 10. For each of the following structures, decide whether the carbohydrate is: (a) an aldose or a ketose (b) a tetrose, pentose or hexosearrow_forwardCarbohydrates a. Compound Z is an aldopentose. If Z is oxidized with nitric acid the product is optically active. If Z undergoes one Ruff degradation and the product of that degradation is reduced to the alditol using H₂/Ni the resulting product is optically inactive. If compound Z undergoes two Ruff degradations, D-glyceraldehyde (shown below) is obtained. Draw the usual Fischer projection of Z (aldehyde at the top). (Hint: work backwards from D- glyceraldehyde.) H HIC OH CH₂OH D-Glyceraldehydearrow_forwardLike glucose, galactose mutarotates when it dissolves in water. The specific rotation ofa-d-galactopyranose is +150.7°, and that of the b anomer is +52.8°. When either ofthe pure anomers dissolves in water, the specific rotation gradually changes to +80.2°.Determine the percentages of the two anomers present at equilibrium.arrow_forward
- Predict the products obtained when d-galactose reacts with each reagent.(a) Br2 and H2Oarrow_forwardExplain the meaning of the following: (a) Chiral carbon (b) Enantiomers (c) Esterificationarrow_forwardTrehalose, C12H22O11, is a nonreducing sugar that is only 45% as sweet as sugar. When hydrolyzed by aqueous acid or the enzyme maltase, it formsonly d-glucose. When it is treated with excess methyl iodide in the presence of Ag2O and then hydrolyzed with water under acidic conditions, only2,3,4,6-tetra-O-methyl-d-glucose is formed. Draw the structure of trehalose.arrow_forward
- Chemistry for Today: General, Organic, and Bioche...ChemistryISBN:9781305960060Author:Spencer L. Seager, Michael R. Slabaugh, Maren S. HansenPublisher:Cengage Learning
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