Compound U is an aldopentose that can be oxidized to an optically inactive aldaric acid V. Upon Kiliani- Fischer reaction, compound U gives to epimeric aldohexoses, W and X. Both W and X give opically active aldaric acids, when oxidized. On Wohl degradation, compound U gives an aldotetrose Y, which upon oxidation gives an optically active aldaric acid (Z). When Y undergoes Wohl degradation, L- Glyceraldehyde is produced. What are structures U to Z? Show the reagents used for each step.

Compound U is an aldopentose that can be oxidized to an optically inactive aldaric acid V. Upon Kiliani- Fischer reaction, compound U gives to epimeric aldohexoses, W and X. Both W and X give opically active aldaric acids, when oxidized. On Wohl degradation, compound U gives an aldotetrose Y, which upon oxidation gives an optically active aldaric acid (Z). When Y undergoes Wohl degradation, L- Glyceraldehyde is produced. What are structures U to Z? Show the reagents used for each step.

Organic Chemistry

8th Edition

ISBN:9781305580350

Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. Foote

Publisher:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. Foote

Chapter10: Alcohols

Section: Chapter Questions

Problem 10.59P

See similar textbooks

Similar questions

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.
An aldose A, is reduced by sodium borohydride to an optically inactive alditol B. The Ruff degredation of A forms C. Oxidation of C by nitric acid generates the optically inactive diacid D. The ruff degreation of C forms D-glyceraldehyde. draw the structures for compounds A through D and discuss a mechanism for the reduction step using sodium borohydride
Ribose, a carbohydrate with the formula shown, forms a cyclic hemiacetal, which, in principle, could contain either a four-membered, five-membered, or six-membered ring. When D-ribose is treated with methanol in the presence of an acid catalyst, two cyclic acetals, A and B, are formed, both with molecular formula C,H,0, These are separated, and each is treated with sodium periodate (Section 10.8C) followed by dilute aqueous acid. Both A and B yield the same three products in the same ratios. он о CHO СНО H+ CH,OH A +B ÕH 1. NalO, 2. H,0* НО CHO + CHOH + CH,OH ÕH CH,OH Isomeric cyclic acetals with molecular formula CH12O, D-Ribose (C;H1605) From this information, deduce whether the cyclic hemiacetal formed by D-ribose is four- membered, five-membered, or six-membered.
What is the product of the starting material D-glyceraldehyde which will (1) produce aldaric acid upon reacting with HNO3 + H2O, NaOCH2, NH2OH, and (CH3CO)2O + NaOCOCH3 (2) produce tartaric acid upon reacting with HNO3 + H2O, NaOCH3, NH2OH, and (CH3CO)2O + NaOCOCH3
When the gum of the shrub Sterculia setigera is subjected to acidic hydrolysis, one of the water-soluble components of thehydrolysate is found to be tagatose. The following information is known about tagatose:(1) Molecular formula C6H12O6(2) Undergoes mutarotation.(3) Does not react with bromine water.(4) Reduces Tollens reagent to give d-galactonic acid and d-talonic acid.(5) Methylation of tagatose (using excess CH3 I and Ag2O) followed by acidic hydrolysis gives1,3,4,5-tetra-O-methyltagatose.(a) Draw a Fischer projection structure for the open-chain form of tagatose.(b) Draw the most stable conformation of the most stable cyclic hemiacetal form of tagatose
Predict the products formed when the following sugars react with excess acetic anhydrideand pyridine.(a) a-d-glucopyranose
Quinapril (trade name Accupril) is used to treat high blood pressure and congestive heart failure. One step in the synthesis of quinapril involves reaction of the racemic alkyl bromide A with a single enantiomer of the amino ester B. (a) What two products are formed in this reaction? (b) Given the structure of quinapril, which one of these two products is needed to synthesize the drug?
Draw the expected product of the reaction of the following sugars with excess methyliodide and silver oxide.(a) a-d-fructofuranose (b) b-d-galactopyranose
The most stable conformation of most aldopyranoses is one in which the largest group, the CH2OH group, is equatorial. However, alpha-D-idopyranose exists primarily in a conformation with an axial CH2OH group. Write formulas for the two chair conformations of a-D-idopyranose (one with the CH2OH group axial and one with the CH2OH group equatorial) and provide an explanation
Draw the expected product of the reaction of the following sugars with excess methyliodide and silver oxide.(a) a-d-fructofuranose
The formation of Br2 from NBS first involves the reaction of NBS with HBr to form an iminol intermediate and molecular bromine. The intermediate then undergoes acid-catalyzed tautomerism to form succinimide, the byproduct of the reaction. Propose a curved-arrow mechanism for the conversion of NBS into succinimide that also accounts for the formation of Br2.
One of the later steps in glucose biosynthesis is the isomerization of fructose 6-phosphate to glucose 6-phosphate. Propose a mechanism, using acid or base catalysis as needed.