Concept explainers
Interpretation:
The two possible structures for the
Concept Introduction:
The Wohl-degradation is opposite of the Killiani-Fisher synthesis. It shortens an aldoses chain by one carbon. Hexoses are converted to pentoses and pentoses are converted to tetroses.
Want to see the full answer?
Check out a sample textbook solutionChapter 21 Solutions
Organic Chemistry; Modified MasteringChemistry with Pearson eText -- ValuePack Access Card; Study Guide and Student Solutions Manual for Organic Chemistry, Books a la Carte Edition (7th Edition)
- Illustrate the treatment of methyl α-D-glucopyranoside with aqueous acid forms a mixture of α- and β-D-glucose and methanol ?arrow_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_forwardCompound 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.)arrow_forward
- Which D-aldopentoses are reduced to optically inactive alditols using NaBH4, CH3OH?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_forwardThe most stable conformation of the pyranose ring of most D-aldohexoses places the largest group, CH2OH, in the equatorial position. An exception to this is the aldohexose D-idose. Draw the two possible chair conformations of either the α or β anomer of D-idose. Explain why the more stable conformation has the CH2OH group in the axial position.arrow_forward
- The 1H NMR spectrum of d-glucose in D2O exhibits two high-frequency doublets. What is responsible for these doublets?arrow_forwardIn 1891, Emil Fischer determined the structures of glucose and the seven other d-aldohexoses using only simple chemical reactions and clever reasoning about stereochemistry andsymmetry. He received the Nobel Prize for this work in 1902. Fischer had determined thatd-glucose is an aldohexose, and he used Ruff degradations to degrade it to (+)-glyceraldehyde. Therefore, the eight d-aldohexose structures shown in Figure 23-3 are the possiblestructures for glucose.Pretend that no names are shown in Figure 23-3 except for glyceraldehyde, and usethe following results to prove which of these structures represent glucose, mannose,arabinose, and erythrose.(a) Upon Ruff degradation, glucose and mannose give the same aldopentose: arabinose.Nitric acid oxidation of arabinose gives an optically active aldaric acid. What are thetwo possible structures of arabinose?(b) Upon Ruff degradation, arabinose gives the aldotetrose erythrose. Nitric acid oxidation of erythrose gives an optically inactive…arrow_forwardIn 1891, Emil Fischer determined the structures of glucose and the seven other d-aldohexoses using only simple chemical reactions and clever reasoning about stereochemistry andsymmetry. He received the Nobel Prize for this work in 1902. Fischer had determined thatd-glucose is an aldohexose, and he used Ruff degradations to degrade it to (+)-glyceraldehyde. Therefore, the eight d-aldohexose structures shown in Figure 23-3 are the possiblestructures for glucose.Pretend that no names are shown in Figure 23-3 except for glyceraldehyde, and usethe following results to prove which of these structures represent glucose, mannose,arabinose, and erythrose.(a) Upon Ruff degradation, glucose and mannose give the same aldopentose: arabinose.Nitric acid oxidation of arabinose gives an optically active aldaric acid. What are thetwo possible structures of arabinose?(b) Upon Ruff degradation, arabinose gives the aldotetrose erythrose. Nitric acid oxidation of erythrose gives an optically inactive…arrow_forward
- Choose the product that is expected when the β-pyranose form of compound A is treated with excess ethyl iodide in the presence of silver oxide. The following information can be used to determine the identity of compound A: 1. The molecular formula of compound A is C6H12O6.2. Compound A is a reducing sugar.3. When compound A is subjected to a Wohl degradation two times sequentially, D-erythrose is obtained.4. Compound A is epimeric with D-glucose at C3.5. The configuration at C2 is R.arrow_forwardList all possible D-2-ketohexoses. One of these D-2-ketohexoses is called sorbose. When sorbose is treated with sodium borohydride it produces a mixture of glucitol and iditol. What is the structure of sorbose? Another D-2-ketohexose, psychosa produces a mixture of alitol and altritol when reduced with sodium borohydride, which is the structure of psychosearrow_forwardA hexose was obtained after (+)-glyceraldehyde underwent three successive Kiliani–Fischer syntheses. Identify the hexose from the following experimental information: oxidation with nitric acid forms an optically active aldaric acid; a Wohl degradation followed by oxidation with nitric acid forms an optically inactive aldaric acid; and a second Wohl degradation forms erythrose.arrow_forward
- ChemistryChemistryISBN:9781305957404Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCostePublisher:Cengage LearningChemistryChemistryISBN:9781259911156Author:Raymond Chang Dr., Jason Overby ProfessorPublisher:McGraw-Hill EducationPrinciples of Instrumental AnalysisChemistryISBN:9781305577213Author:Douglas A. Skoog, F. James Holler, Stanley R. CrouchPublisher:Cengage Learning
- Organic ChemistryChemistryISBN:9780078021558Author:Janice Gorzynski Smith Dr.Publisher:McGraw-Hill EducationChemistry: Principles and ReactionsChemistryISBN:9781305079373Author:William L. Masterton, Cecile N. HurleyPublisher:Cengage LearningElementary Principles of Chemical Processes, Bind...ChemistryISBN:9781118431221Author:Richard M. Felder, Ronald W. Rousseau, Lisa G. BullardPublisher:WILEY