Question 1

Which of the following structures represent epimers?

Accepted Answer

A) I and II 
B) III and V 
C) III and IV 
D) I and III 
E) Pairs in more than one of these choices. 
A) I and II 
B) III and V 
C) III and IV 
D) I and III 
E) Pairs in more than one of these choices.

Question 2

An aldaric acid is represented by:

Accepted Answer

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

Question 3

Consider the structures shown below.Which structure represents $\beta$-d-glucopyranose?

Accepted Answer

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

Question 4

An optically active hexose (A),C6H12O6,was degraded to an optically active pentose (B),C5H10O5,by the following series of reactions:   Compound (B)was degraded to an optically active tetrose (C),C4H8O4,through the same series of reactions as shown above; then (C)was oxidized with HNO3 to yield meso tartaric acid.
Give possible structure for (A)and (B).

Accepted Answer

Question 5

If the methyl glycoside of an aldohexose is treated with HIO4,one molar equivalent of HCHO is formed but no HCOOH.What size ring is present in the glycoside?

Accepted Answer

A) Three-membered 
B) Four-membered 
C) Five-membered 
D) Six-membered 
E) Seven-membered 
A) Three-membered 
B) Four-membered 
C) Five-membered 
D) Six-membered 
E) Seven-membered

Question 6

A polysaccharide found in the shells of lobsters,crabs,and in the exoskeletons of insects and spiders is called ___.

Accepted Answer

The answer of A polysaccharide found in the shells of...

Question 7

What products are expected to be formed upon subjecting d-galactose (shown below)to the following reaction sequence? (Draw Fischer projection formulas.)
i)Br2,H2O; ii)H2O2,Fe2(SO4)3

Accepted Answer

Question 8

Complete the following reaction:

Accepted Answer

The answer of Complete the following reaction:  ...

Question 9

Refer to the structures below.Which are l-sugars?

Accepted Answer

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

Question 10

What is the structural similarity between chitin and cellulose?

Accepted Answer

They are both @#LAT-DLM&(1@#LAT-DLM&4)glycosides.N

Question 11

Refer to the structures below.Which sugar(s)would yield an optically active aldaric acid on oxidation with nitric acid?

Accepted Answer

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

Question 12

The d-glucose unit at the branching point of amylopectin has free hydroxyl groups at which positions?

Accepted Answer

A) C2,C3,and C6 
B) C2 and C3 
C) C3 and C4 
D) C3,C4,and C6 
E) C4 and C6 
A) C2,C3,and C6 
B) C2 and C3 
C) C3 and C4 
D) C3,C4,and C6 
E) C4 and C6

Question 13

Complete the reaction and give the structure and name of the product(s):

Accepted Answer

The answer of Complete the reaction and give the structure...

Question 14

Name each of the following compounds:

Accepted Answer

a)d-galactonic acid

Question 15

Consider the structures below.An l-aldohexose,X,is treated with nitric acid to yield an optically inactive aldaric acid.The same l-aldohexose,X,is subjected to a Ruff degradation and the degradation product is oxidized with nitric acid to produce an optically inactive aldaric acid.Which is a possible structure for X?

Accepted Answer

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

Question 16

Many other sugars besides glucose exhibit mutarotation.For example,α-d-galactopyranose has [α]D = +150.7,and β-d-galactopyranose has [α]D = +52.8.Show how the equilibrium percentages of α and β anomers can be calculated from the equilibrium specific rotation of +80.2.

Accepted Answer

Percentage of the anomer β at

Question 17

When the name of a monosaccharide is preceded only by (+),it can be said,correctly,that:

Accepted Answer

A) The compound is the α-anomer. 
B) The compound exists in the pyranose form. 
C) The compound is dextrorotatory. 
D) The compound has the same stereochemistry at the penultimate carbon as d-(+)-glucose. 
E) The compound exists only in open-chain form. 
A) The compound is the α-anomer. 
B) The compound exists in the pyranose form. 
C) The compound is dextrorotatory. 
D) The compound has the same stereochemistry at the penultimate carbon as d-(+)-glucose. 
E) The compound exists only in open-chain form.

Question 18

α-d-Glucose has [α]D = +112,and β-d-glucose has [α]D = +19.If either anomer is dissolved in water and allowed to reach equilibrium,the specific rotation of the solution is +52.What are the percentages of each anomer at equilibrium?

Accepted Answer

Percentage of the β-anomer at

Question 19

A d-aldohexose,Z,is subjected to a Ruff degradation.The degradation product is treated with nitric acid to yield an optically active aldaric acid.A possible structure for Z is:

Accepted Answer

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

Question 20

What reagents could be used to selectively protect the HO groups at positions 1 and 6 of a hexose?

Accepted Answer

A) TBDPS-Cl,AgNO3 followed by acetic anhydride. 
B) CH3OH/HCl followed by TBDPS-Cl. 
C) CH3CO2H,HCl followed by (CH3)3C(C6H5)2-SiCl. 
D) Acetic anhydride followed by acetone. 
E) Benzaldehyde followed by CH3OH/HCl. 
A) TBDPS-Cl,AgNO3 followed by acetic anhydride. 
B) CH3OH/HCl followed by TBDPS-Cl. 
C) CH3CO2H,HCl followed by (CH3)3C(C6H5)2-SiCl. 
D) Acetic anhydride followed by acetone. 
E) Benzaldehyde followed by CH3OH/HCl.

Exam 22: Carbohydrates

Which of the following structures represent epimers?

An aldaric acid is represented by:

Consider the structures shown below.Which structure represents β\betaβ -d-glucopyranose?

If the methyl glycoside of an aldohexose is treated with HIO4,one molar equivalent of HCHO is formed but no HCOOH.What size ring is present in the glycoside?

A polysaccharide found in the shells of lobsters,crabs,and in the exoskeletons of insects and spiders is called ___.

What products are expected to be formed upon subjecting d-galactose (shown below)to the following reaction sequence? (Draw Fischer projection formulas.) i)Br2,H2O; ii)H2O2,Fe2(SO4)3

Complete the following reaction:

Refer to the structures below.Which are l-sugars?

What is the structural similarity between chitin and cellulose?

Refer to the structures below.Which sugar(s)would yield an optically active aldaric acid on oxidation with nitric acid?

The d-glucose unit at the branching point of amylopectin has free hydroxyl groups at which positions?

Complete the reaction and give the structure and name of the product(s):

Name each of the following compounds:

Many other sugars besides glucose exhibit mutarotation.For example,α-d-galactopyranose has [α]D = +150.7,and β-d-galactopyranose has [α]D = +52.8.Show how the equilibrium percentages of α and β anomers can be calculated from the equilibrium specific rotation of +80.2.

When the name of a monosaccharide is preceded only by (+),it can be said,correctly,that:

α-d-Glucose has [α]D = +112,and β-d-glucose has [α]D = +19.If either anomer is dissolved in water and allowed to reach equilibrium,the specific rotation of the solution is +52.What are the percentages of each anomer at equilibrium?

A d-aldohexose,Z,is subjected to a Ruff degradation.The degradation product is treated with nitric acid to yield an optically active aldaric acid.A possible structure for Z is:

What reagents could be used to selectively protect the HO groups at positions 1 and 6 of a hexose?

The Basics

Families of Carbon

Acids and Bases

Nomenclature and Conformations of Alkanes and Cycloalkanes

Stereochemistry

Nucleophilic Reactions

Alkenes and Alkynes I

Alkenes and Alkynes II

Nuclear Magnetic Resonance and Mass Spectrometry

Radical Reactions

Alcohols and Ethers

Alcohols From Carbonyl Compounds

Conjugated Unsaturated Systems

Aromatic Compounds

Reactions of Aromatic Compounds

Aldehydes and Ketones

Carboxylic Acids and Their Derivatives

Reactions at the Α Carbon of Carbonyl Compounds

Condensation and Conjugate Addition Reactions of Carbonyl Compounds

Amines

Transition Metal Complexes

Lipids

Amino Acids and Proteins

Nucleic Acids and Protein Synthesis

Filters

Consider the structures shown below.Which structure represents $\beta$ -d-glucopyranose? $Consider the structures shown below.Which structure represents \beta -d-glucopyranose?$

If the methyl glycoside of an aldohexose is treated with HIO₄,one molar equivalent of HCHO is formed but no HCOOH.What size ring is present in the glycoside?

What products are expected to be formed upon subjecting d-galactose (shown below)to the following reaction sequence? (Draw Fischer projection formulas.) i)Br₂,H₂O; ii)H₂O₂,Fe₂(SO₄)₃

Many other sugars besides glucose exhibit mutarotation.For example,α-d-galactopyranose has [α]_D = +150.7,and β-d-galactopyranose has [α]_D = +52.8.Show how the equilibrium percentages of α and β anomers can be calculated from the equilibrium specific rotation of +80.2.

α-d-Glucose has [α]_D = +112,and β-d-glucose has [α]_D = +19.If either anomer is dissolved in water and allowed to reach equilibrium,the specific rotation of the solution is +52.What are the percentages of each anomer at equilibrium?