Deck 20: Special Topic: Carbohydrates

Question 1

Which of the structures shown here are -anomers of D-sugars?

A) I
B) II
C) III and IV
D) I, III, and IV
E) all

Answer 1

II

Question 2

Consider the structures shown and complete the sentence.
- Maltose is a disaccharide, which is formed by

A) two molecules of D-glucose, joined by an -1-4 linkage.
B) two molecules of D-glucose, joined by a -1-4 linkage.
C) two molecules of D-glucose, joined by a 1-6 linkage.
D) an -1-4 linkage between C-1 atom of molecule of D-glucose and C-4 atom of galactose.
E) a-1-6 linkage between C-1 atom of molecule of L-glucose and C-6 atom of D-glucose .

Answer 2

two molecules of D-glucose, joined by an -1-4 linkage.

Question 3

What is the product of the following reaction?

A)
B)
C)
D)
E)

Answer 3

Question 4

Which of the following structures corresponds to the Fischer projection shown?

A)
B)
C)
D)
E)

Question 5

D-Glucose was treated with calcium hydroxide in aqueous solution.What is the product of this reaction?

A)calcium gluconate
B)L-glucose
C)no reaction occurs
D)D-fructose
E)a mixture consisting mainly of D-glucose and D-fructose

Question 6

Which of the following statements about mutarotation of sugars is false?

A) Mutarotation of -glucopyranose in water results in a mixture of -glucopyranose and - glucopyranose.
B) -Glucopyranose is the predominant form in water.
C) Mutarotation can only happen in basic media.
D) Mutarotation proceeds via an open-chain form of a carbohydrate.
E) I-O -Methyl- -glucopyranose does not ungergo mutarotation.

Question 7

D-glucaric acid can also be named L-gularic acid.Complete the sentence. D-glucitol and L-gulitol are ____________

A)identical compounds.
B)enantiomers.
C)epimers.
D)diastereomers, but not epimers.
E)compounds whose relationship cannot be deduced from the facts provided above.

Question 8

Which of the following sugars would produce the same osazone?

A) I and II
B) I and III
C) II and III
D) II and IV
E) III and IV

Question 9

Predict the product of the following reaction conditions.

A)
B)
C)
D)
E)

Question 10

What is the product of the following oxidation of D-altrose?

A)
B)
C)
D)
E)

Question 11

Which of these structures is -L-arabinose? The Fischer projection of L -arabinose is shown.

A)
B)
C)
D)
E)

Question 12

Which of the following sugars is a ketopentose?

A)
B)
C)
D)
E)

Question 13

Which pair of structures represents the same stereoisomer?

A) X and Y
B) Y and Z
C) Z and W
D) X and Z
E) Y and W

Question 14

Which of the following structures would be a product of the conditions shown?

A)
B)
C)
D)
E)

Question 15

What is the product of the following reaction?

A)
B)
C)
D)
E)

Question 16

Which of the following sugars is an aldotetrose?

A)
B)
C)
D)
E)

Question 17

An aldopentose is oxidized with sodium nitrite and nitric acid to produce an optically active aldaric acid.The same aldopentose is treated with Ruff degradation conditions and the product is Reduced with sodium borohydride to give an optically inactive alditol.Which of the following Structures is the aldopentose?

A)
B)
C)
D)
E)

Question 18

Which of the following is the correct name for this structure? (The Fischer projections of D-gulose and L-gulose are shown.)

A) -D-gulofuranose
B) -D-gulopyranose
C) -D-gulofuranose
D) -L-gulofuranose
E) -D-gulopyranose

Question 19

Which of the following structures are furanose forms?

A) I and IV
B) II and III
C) I and II
D) III and IV
E) none of these structures

Question 20

Which of the Fischer projections corresponds to the following structure?

A)
B)
C)
D)
E)

Question 21

Predict the product of the following reaction

Question 22

Ketosaccharides, such as fructose, are generally considered nonreducing sugars, since they lack a
free aldehyde group in an open-chain form.However, in strongly basic media fructose reacts with
copper-based oxidants, thus exhibiting the reducing sugar properties.Explain this phenomenon.

Question 23

A certain aldotetrose, A , produces an optically active aldaric acid on oxidation with sodium nitrite and nitric acid. When A is subjected to modified Kiliani-Fischer conditions, two compounds are produced, B and C . On sodium borohydride reduction, B yields an optically inactive alditol, while C gives an optically active alditol. The configurational carbon in A,B , and C matches that of R -glyceraldehyde. What are the structures of A, B , and C ?

Question 24

Even though glucose is an aldose, its ¹H NMR spectrum shows virtually no signal for the aldehyde proton. Explain this fact.

Question 25

Draw a Fischer projection of the compound below, placing the most oxidized carbon on top.

Question 26

Draw a Fischer projection for the sugar shown.

Question 27

Draw the structure of the product that would result when D-allose is subjected to the conditions shown.

Question 28

Two L-aldohexoses, A and B, are subjected to oxidation with sodium nitrite and nitric acid.A
gives an optically active aldaric acid, while B gives an optically inactive aldaric acid.When A and
B are reduced with sodium borohydride, A produces an optically active alditol, and B produces an
optically inactive alditol.Ruff degradation of either A or B gives the same compound.What are
the structures of A and B?

Question 29

What is a complete IUPAC name for this form of galactose?

Question 30

What is a complete IUPAC name for this form of talose?

Question 31

The structure of D-allose is shown below. Draw the most thermodynamically stable anomer of D-allopyranose. Is it ?

Question 32

What is the product of the following reaction?

Question 33

Predict the product of the following transformation.

Question 34

What is a complete IUPAC name for this form of galactose?

Question 35

Xylobiose is a disaccharide consisting of two D-xylopyranose units in a linkage between C-1 of one unit and C-4 of the other. Draw xylobiose using Haworth projections. The structure of D-xylose is provided.

Question 36

A sugar was subjected to the reaction conditions shown. Draw the structure of the products of these conditions.

Question 37

Either of two sugars could have been the starting material for a Ruff degradation to produce the
monosaccharide shown here.Draw Fischer projections of these two sugars.

Question 38

Predict the product of the following reaction conditions.

Question 39

Draw the structure of the sugar that underwent the indicated conditions to produce these two
products.

Question 40

Draw the structure of alpha-D-ribofuranose.The Fischer projection for D-ribose is shown.