Concept explainers
(a)
Interpretation: The aldoses formed when D-threose is subjected to the Kiliani–Fischer synthesis are to be predicted.
Concept introduction: Kiliani–Fischer synthesis is a method which is used for the elongation of the carbon chains in aldose. In this method, the aldose chain is elongated by the formation of new stereogenic centre at
(b)
Interpretation: The aldoses formed when D-ribose is subjected to the Kiliani–Fischer synthesis are to be predicted.
Concept introduction: Kiliani–Fischer synthesis is a method which is used for the elongation of the carbon chains in aldose. In this method, the aldose chain is elongated by the formation of new stereogenic centre at
(c)
Interpretation: The aldoses formed when D-galactose is subjected to the Kiliani–Fischer synthesis are to be predicted.
Concept introduction: Kiliani–Fischer synthesis is a method which is used for the elongation of the carbon chains in aldose. In this method, the aldose chain is elongated by the formation of new stereogenic centre at
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- 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 NaBH 4 converts aldose U into an optically inactive (meso) alditol V. Ruff degradation ofU gives W, whose alditol is optically inactive. Ruff degradation of W forms D-glyceraldehyde, thesimplest aldose. Upon Kiliani-Fischer synthesis, U is converted to two aldoses, X and Y. X is oxidized toan optically active aldaric acid Z. Y is oxidized to an optically inactive aldaric acid. Draw the structuresof D-glyceraldehyde, V, W, X, Y, and Z. Structure of compound U is shown below.arrow_forwardAlthough reaction occurs in sugars also. H, OH H H-C-OH Oxidizing agent OH OH Н-С-ОН Н-С-ОН C=0 R OH R R R Aldose Aldonic acid anion Ketose Enediol Copyright © 2007 Pearson Prentice Hall, Inc. Draw the reaction above substituting D-fructose instead of the generalized ketose structure shown above (you need to draw all 4 structures). Slan and upload your drawing.arrow_forward
- Identify compounds A–D. A D-aldopentose A is oxidized with HNO3 to an optically inactive aldaric acid B. A undergoes the Kiliani–Fischer synthesis to yield C and D. C is oxidized to an optically active aldaric acid. D is oxidized to an optically inactive aldaric acidarrow_forward.. Draw Haworth projections for the following: (a) CHO in a-furanose form. Name the sugar. H-C- OH но-с—н H-C-OH CH,OH (b) The L isomer of (a) (c) a-D-GlcNAc (d) (d) a-D-Fructofuranosearrow_forwardThe following observations are obtained after a D-hexose was made to react with several reagents: (1) The reactions of a D-hexose with (a) to (d) below yields an aldaric acid (a) NH₂OH, (b) (CH3CO)₂O, NaOCOCH 3, and, (c) NaOCH3, and then, (d) HNO3, H₂O (2) HNO3 oxidation of the same D-hexose gives an aldaric acid. Predict the structures of the three (3) possible hexoses that can undergo the above reactions?arrow_forward
- Draw the alkene that is needed to synthesize glutamine by an enantioselective hydrogenation reaction using H₂ and Rh.arrow_forwardAn oligosaccharide isolated from an organism is found tocontain two glucose residues and one galactose residue.Exhaustive methylation followed by hydrolysis producedtwo glucoses with methoxy groups at positions 2, 3,and 6 and galactose with methoxy groups at positions2, 3, 4, and 6. What is the structure of the originaloligosaccharide?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_forward
- Introduction to General, Organic and BiochemistryChemistryISBN:9781285869759Author:Frederick A. Bettelheim, William H. Brown, Mary K. Campbell, Shawn O. Farrell, Omar TorresPublisher:Cengage LearningOrganic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage Learning