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
Want to see the full answer?
Check out a sample textbook solutionChapter 28 Solutions
ORGANIC CHEMISTRY-MOLYMOD PACKAGE
- An 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_forwardGiven the following structure of aldose, (a) how many chiral carbons are there? (b) is it a reducing sugar? and (c) is it an L or D sugar?arrow_forwardAn aldopentose "O", is oxidized with HNO3 to a diacid "P" which is optically active. The compound "O", is also degraded to an aldotetrose "Q" which undergoes another oxidation to an optically inactive diacid "R". Assuming that "O" has the configuration D-(4R); what are the structures of "O" to "R"?arrow_forward
- Treatment 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(a) Which of the d-aldopentoses will give optically active aldaric acids on oxidation with HNO3 ?(b) Which of the d-aldotetroses will give optically active aldaric acids on oxidation with HNO3 ?(c) Sugar X is known to be a d-aldohexose. On oxidation with HNO3, X gives an optically inactive aldaric acid. WhenX is degraded to an aldopentose, oxidation of the aldopentose gives an optically active aldaric acid. Determine thestructure of X.(d) Even though sugar X gives an optically inactive aldaric acid, the pentose formed by degradation gives an opticallyactive aldaric acid. Does this finding contradict the principle that optically inactive reagents cannot form opticallyactive products?(e) Show what product results if the aldopentose formed from degradation of X is further degraded to an aldotetrose.Does HNO3 oxidize this aldotetrose to an optically active aldaric acid?arrow_forwardWhich D-aldopentose is oxidized to an optically active aldaric acid and undergoes the Wohl degradation to yield a D-aldotetrose that is oxidized to an optically active aldaric acid?arrow_forward