1. Reactions of carbohydrates
Hemiacetal Formation
Reduction
Oxidation
Osazone Formation
Chain Shortening
Chain Lengthening

2. Cyclic hemiacetals Form readily when
hydroxyl and carbonyl groups are in the same molecule
and a five or six-membered ring can form

3. Haworth Projections b-anomer a-anomer
Most commonly drawn with the anomeric carbon on the right and the hemiacetal oxygen to the back right
anomeric carbon: the new stereocenter resulting from cyclic hemiacetal formation
anomers: carbohydrates that differ in configuration at their anomeric carbons
The designation - means that -OH on the anomeric carbon is cis to the terminal -CH2OH; - means that it is trans
Anomeric
carbon
b-anomer
a-anomer

4. Ring Formation 72% As a solid, glucose exists as a ring structure.| H
|C|C|C|C|C|H OH HO
As a solid, glucose exists as a ring structure.
b-D-glucose 1. OH O 2. 3. 4. 5. 6. 2. 3. 1. 4. 5.
In a solution, 99% of the glucose is in the ring structure. The other 1% is the open chain. OH O 2. 3. 4. 5. 6. 6. OH 1.
D-glucose
a-D-glucose

5. Conformational Formulas
compare the orientations of groups on carbons 1-5 in the Haworth and chair representations of b-D-glucopyranose
in each case they are up-down-up-down-up

6. Haworth of D-Fructose OH b-D-fructose | | C | H |C|C|C|C|C|H | O | HO
a-D-fructose
D-fructose

7. Mutarotation
Mutarotation: the change in specific rotation that occurs when an  or  form of a carbohydrate is converted to an equilibrium mixture of the two

8. Mutarotation
72%

9. Epimerization
In base, H on C2 may be removed to form enolate ion. Reprotonation may change the stereochemistry of C2.

10. Enediol Rearrangement
In base, the position of the C=O can shift. Chemists use acidic or neutral solutions of sugars to preserve their identity.

11. Reduction of Simple Sugars
C=O of aldoses or ketoses can be reduced to C-OH by NaBH4 or H2/Ni.
Name the sugar alcohol by adding -itol to the root name of the sugar.
Reduction of D-glucose produces D-glucitol, commonly called D-sorbitol.
Reduction of D-fructose produces a mixture of D-glucitol and D-mannitol.

12. Oxidation by Bromine
Bromine water oxidizes aldehyde, but not ketone or alcohol; forms aldonic acid.

13. Aldose Oxidation to Aldonic Acids
Oxidation of the -CHO group of an aldose to a CO2H group can be carried out using Tollens’, Benedict’s, or Fehling’s solutions

14. Ketose Oxidation to Aldonic Acids
2-Ketoses are also oxidized by these reagents because, under the conditions of the oxidation, 2-ketoses equilibrate with isomeric aldoses

15. Oxidation by Tollens Reagent
Tollens reagent reacts with aldehyde, but the base promotes enediol rearrangements, so ketoses react too.
Sugars that give a silver mirror with Tollens are called reducing sugars.
All monosaccharides are reducing sugars

16. Nonreducing Sugars
Glycosides are acetals, which stable in base, so they do not react with Tollens reagent.
Some disaccharides are also acetals (nonreducing).
All polysaccharides are also acetals, (nonreducing).

17. Oxidation by Nitric Acid
Nitric acid oxidizes both the aldehyde and the terminal alcohol; forms aldaric acid.

18. Formation of Glycosides
React the sugar with alcohol in acid.
Since the open chain sugar is in equilibrium with its - and -hemiacetal, both anomers of the acetal are formed.
Aglycone is the term used for the group bonded to the anomeric carbon.

19. Ether Formation
Convert all -OH groups to -OR, using a modified Williamson synthesis, after converting sugar to acetal, stable in base.

20. Ester Formation
Acetic anhydride with pyridine catalyst converts all the oxygens to acetate esters.

21. Osazone Formation
Both C1 and C2 react with phenylhydrazine.

22. Osazone Sugars that differ in configuration only at the a-carbon
Give the same product.

23. Ruff Degradation
Aldose chain is shortened by oxidizing the aldehyde to -COOH, then decarboxylation.

24. Kiliani-Fischer Synthesis
This process lengthens the aldose chain.
A mixture of C2 epimers is formed.

25. Determination of Ring Size
Haworth determined the pyranose structure of glucose in 1926.
The anomeric carbon can be found by methylation of the -OH’s, then hydrolysis.

26. Periodic Acid Reactions
Periodic acid ( HIO4 or H5IO6 ) cleaves the C-C bond between an alcohol and an adjacent alcohol (vicinal) or carbonyl group.
Does not affect ethers or acetals.
Two carbonyl compounds are formed:
1° alcohols oxidize to formaldehyde 2° alcohols oxidize to aldehydes
aldehydes oxidize to formic acid
ketones oxidize to carboxylic acids
carboxylic acids oxidize to CO2

27. Use of Periodic Acid Cleavage
Separation and identification of the products determine the size of the ring.

28. Reduction to Alditols
The carbonyl group of a monosaccharide can be reduced to an hydroxyl group by a variety of reducing agents, including NaBH4 and H2/M

29. You try it:
Oxidation of which two hexoses would give the same product??

30. Which of the following aldaric acids are optically active?
Question #1
Which of the following aldaric acids are optically active?
C and D
A B C D E
meso
No stereocenter
R, R
S, S
meso

31. Question #2
Draw a hexose that would give the same aldaric acid product as D-Glucose D

32. Question #2
Draw a hexose that would give the same aldaric acid product as D-Glucose D

33. Question #3
There are four D-aldopentoses. Draw Fischer projections of each of them. Then draw Fischer projections of the aldaric acids they would yield. Label each center as a R or S configuration. Circle the aldaric acids that are optically inactive?

34. Question #3
There are four D-aldopentoses. Draw Fischer projections of each of them. Then draw Fischer projections of the aldaric acids they would yield. Label each center as a R or S configuration. Circle the aldaric acids that are optically inactive?

35. Question #4 Select the compounds that would produce the same osazone.
A and D, B and C

36. Common Modifications to monosaccharides
Deoxy sugars
Amino sugars
Glycosides (acetal)

37. Deoxy Sugar

38. Amino Sugar
Glucosamine

39. Formation of Glycosides - Acetals
A monosaccharide hemiacetal can react with a second molecule of an alcohol to form an acetal
A ‘glycoside’ bond

40. Glycosides
Glycoside bond: the bond from the anomeric carbon of the glycoside to an -OR group.
Cyclic acetals are not in equilibrium with their open chain carbonyl-containing forms. Glycosides do NOT undergo mutarotation.
List the name of the alkyl or aryl group attached to oxygen followed by the name of the carbohydrate with the ending -e replaced by -ide
methyl -D-glucopyranoside
methyl -D-ribofuranoside

41. Formation of Glycosides
A methyl b-D-glucoside
Methyl b-D-glucopyranoside
Is this a reducing sugar glycoside?
NO!

42. Maltose Lactose Sucrose Cellobiose
Disaccharides
Maltose
Lactose
Sucrose
Cellobiose

43. Disaccharides Three naturally occurring glycosidic linkages:
1-4’ link: The anomeric carbon is bonded to oxygen on C4 of second sugar.
1-6’ link: The anomeric carbon is bonded to oxygen on C6 of second sugar.
1-1’ link: The anomeric carbons of the two sugars are bonded through an oxygen.

44. Maltose
From malt, the juice of sprouted barley and other cereal grains. (Cellulose)
4-O-(a-D-glucopyranosyl)-D-glucopyranose
Yes! NO
Is this a reducing sugar?
Yes!

45. Lactose The principle sugar present in milk
5% - 8% in humans, 5% in cow’s milk
4-O-(b-D-galactopyranosyl)-D-glucopyranose
Yes! NO
Is this a reducing sugar?
Yes!

46. Sucrose
Table sugar, obtained from the juice of sugar cane and sugar beet.
1-O-(a-D-galactopyranosyl)- b- D-fructofurananoside OR
1-O-(b- D-fructofurananosyl)- a-D-galactopyranoside NO
No!
Is this a reducing sugar?
No!

47. N-Glycosides
The anomeric carbon of a cyclic hemiacetal undergoes reaction with the N-H group of an amine to form an N-glycoside
N-glycosides of the following purine and pyrimidine bases are structural units of nucleic acids

48. N-Glycosides

49. Formation of N-Glycosides (Nucleosides)
For example, reaction between b-D-ribofuranose and cytosine produces water and uridine, one of the structural units of RNA:

50. Gentiobiose Two glucose units linked 1-6’. Common carbohydrate
branch point

51. Polysaccharides
Polysaccharides are chains of five or more monosaccharide:
Starch – a glucose polymer that is the storage carbohydrate used by plants.
Glycogen – a glucose polymer that is the storage carbohydrate used by animals.
Cellulose – a glucose polymer that is a major component of the cell wall in plants & algae.
Agar – natural component of certain seaweed polymer of galactose & sulfur containing carbohydrates.
Chitin – polymer of glucosamine (a sugar with an amino functional group).

52. Starch Starch is used for energy storage in plants
it can be separated into two fractions; amylose and amylopectin. Each on complete hydrolysis gives only D-glucose
amylose is composed of continuous, unbranched chains of up to 4000 D-glucose units joined by a-1,4-glycoside bonds
amylopectin is a highly branched polymer of D-glucose. Chains consist of units of D-glucose joined by a-1,4-glycoside bonds and branches created by a-1,6-glycoside bonds

53. Amylopectin

54. Glycogen The reserve carbohydrate for animals
a nonlinear polymer of D-glucose units joined by a-1,4- and a-1,6-glycoside bonds bonds
the total amount of glycogen in the body of a well-nourished adult is about 350 g (about 3/4 of a pound) divided almost equally between liver and muscle

55. Cellulose
Cellulose is a linear polymer of D-glucose units joined by b-1,4-glycoside bonds
it has an average molecular weight of 400,000, corresponding to approximately 2800 D-glucose units per molecule

56. Cellulose

57. Polysaccharides Digestion
Polymers of Glucose
Starch is digestable
Cellulose is not
digestable by humans

58. Modification of Cellulose
Cellulose Nitrate called guncotton
Pyroxylin Partially nitrated photographic film and lacquers
Cellulose Acetate film explosive
Cellulose reprocessed Rayon via carbon disulfide

59. Cellulose fibre - Rayon

60. Membrane Carbohydrates
Membranes of animal plasma cells have large numbers of relatively small carbohydrates bound to them
these membrane-bound carbohydrates are part of the mechanism by which cell types recognize each other; they act as antigenic determinants
Early discovery of these antigenic determinants are the blood group substances
A, B, AB, and O

61. ABO Blood Classification
In the ABO system, individuals are classified according to four blood types:
A, B, AB, and O
at the cellular level, the biochemical basis for this classification is a group of relatively small membrane-bound carbohydrates

62. ABO Blood Classification

63. ABO and Disease
Some infectious disease organisms have ABO antigens on their cell walls conferring resistance to those that can produce the antibodies and increases the susceptibility of those whose blood type matches the antigens. A
Syphilis, Smallpox, Bronchial Pneumonia, Rhuematic Heart Disease B
Infantile Diarrhea, Typhoid Fever, Scarlet Fever C
Bubonic Plague, Paratyphoid, Scarlet Fever, Cholera

64. Glucose Assay
The glucose oxidase method is completely specific for D-glucose

65. ‘Chemstrip Kit’ Blood glucose test for diabetics
Based on reaction of o-toluidine with glucose

66. Biosynthesis with Glucose

67. Cellulose Polymer of D-glucose, found in plants.
Mammals lack the -glycosidase enzyme.

68. Amylose Soluble starch, polymer of D-glucose.
Starch-iodide complex, deep blue.

69. Amylopectin
Branched, insoluble fraction of starch.

70. Glycogen
Glucose polymer, similar to amylopectin, but even more highly branched.
Energy storage in muscle tissue and liver.
The many branched ends provide a quick means of putting glucose into the blood.

71. Chitin
Polymer of N-acetylglucosamine.
Exoskeleton of insects.

72. Nucleic Acids
Polymer of ribofuranoside rings linked by phosphate ester groups.
Each ribose is bonded to a base.
Ribonucleic acid (RNA)
Deoxyribonucleic acid (DNA)

73. Ribonucleosides
A -D-ribofuranoside bonded to a heterocyclic base at the anomeric carbon.

74. Ribonucleotides
Add phosphate at 5’ carbon.

75. Structure of RNA

76. Structure of DNA -D-2-deoxyribofuranose is the sugar.
Heterocyclic bases are cytosine, thymine (instead of uracil), adenine, and guanine.
Linked by phosphate ester groups to form the primary structure.

77. Base Pairings

78. Double Helix of DNA
Two complementary polynucleotide chains are coiled into a helix.
Described by Watson and Crick, 1953.

79. DNA Replication

80. Additional Nucleotides
Adenosine monophosphate (AMP), a regulatory hormone.
Nicotinamide adenine dinucleotide (NAD), a coenzyme.
Adenosine triphosphate (ATP), an energy source.

81. Amino Acids with Aliphatic R-Groups

82. Protein Titration Curve Alanine

83. Common Modifications to Monosaccharides
Deoxy sugars
Amino sugars
Glycosides (acetal)

84. Deoxy Sugar

85. Amino Sugar
Glucosamine

86. Formation of Glycosides - Acetals
Glycoside: a carbohydrate in which the -OH of the anomeric carbon is replaced by -OR
A monosaccharide hemiacetal can react with a second molecule of an alcohol to form an acetal
A ‘glycoside’ bond

87. Glycosides
Glycoside bond: the bond from the anomeric carbon of the glycoside to an -OR group.
Unlike cyclic hemiacetals, cyclic acetals are not in equilibrium with their open chain carbonyl-containing forms.
Glycosides do NOT undergo mutarotation.

88. Naming Glycosides
List the name of the alkyl or aryl group attached to oxygen followed by the name of the carbohydrate with the ending -e replaced by -ide
methyl -D-glucopyranoside
methyl -D-ribofuranoside

89. Glucopyranoside
Methyl b-D-glucopyranoside
(methyl b-D-glucoside)

90. Maltose Lactose Sucrose
Disaccharides
Maltose
Lactose
Sucrose

91. Maltose
From malt, the juice of sprouted barley and other cereal grains

92. -Maltose

93. Lactose The principle sugar present in milk
about 5% - 8% in human milk, 4% - 5% in cow’s milk

94. -Lactose

95. Sucrose
Table sugar, obtained from the juice of sugar cane and sugar beet

96. Sucrose

97. N-Glycosides
The anomeric carbon of a cyclic hemiacetal undergoes reaction with the N-H group of an amine to form an N-glycoside
N-glycosides of the following purine and pyrimidine bases are structural units of nucleic acids

98. N-Glycosides

99. Formation of N-Glycosides (Nucleosides)
For example, reaction between b-D-ribofuranose and cytosine produces water and uridine, one of the structural units of RNA:

100. Disaccharides Three naturally occurring glycosidic linkages:
1-4’ link: The anomeric carbon is bonded to oxygen on C4 of second sugar.
1-6’ link: The anomeric carbon is bonded to oxygen on C6 of second sugar.
1-1’ link: The anomeric carbons of the two sugars are bonded through an oxygen.

101. Cellobiose Two glucose units linked 1-4’. Disaccharide of cellulose.
A mutarotating, reducing sugar.
=>

102. Maltose
Two glucose units linked 1-4’.
=>

103. Lactose
Galactose + glucose linked 1-4’.
“Milk sugar.”
=>

104. Gentiobiose Two glucose units linked 1-6’.
Rare for disaccharides, but commonly seen as branch point in carbohydrates.
=>

105. Sucrose
Glucose + fructose, linked 1-1’
Nonreducing sugar
=>

106. Polysaccharides
Polysaccharides are chains of five or more monosaccharide:
Starch – glucose polymer that is the plant storage carbohydrate
Glycogen – glucose polymer that is the animal storage carbohydrate
Cellulose – glucose polymer that is a major component of the cell wall in plants & algae.
Agar – natural component of certain seaweed polymer of galactose & sulfur containing carbohydrates.
Chitin – polymer of glucosamine (an amino sugar), found in the exoskeleton of bugs.

107. Starch Starch is used for energy storage in plants
Two types: amylose and amylopectin. On complete hydrolysis each type gives only D-glucose
Amylose: is composed of continuous, unbranched chains of up to 4000 D-glucose units joined by a-1,4-glycoside bonds
Amylopectin: is a highly branched polymer of D- glucose. Chains consist of units of D- glucose joined by a-1,4-glycoside bonds and branches created by a-1,6-glycoside bonds

108. Amylopectin

109. Glycogen The reserve carbohydrate for animals
A nonlinear polymer of D-glucose units joined by a-1,4- and a-1,6-glycoside bonds bonds.
The total amount of glycogen in the body of a well-nourished adult is about 350 g (about 3/4 of a pound) divided almost equally between liver and muscle.

110. Cellulose
Cellulose is a linear polymer of D-glucose units joined by b-1,4-glycoside bonds.
Average molecular weight of 400,000, corresponds to approximately 2800
D-glucose units per molecule.

111. Cellulose

112. Polysaccharides Digestion
Polymers of Glucose
Starch is digestable
Cellulose is not
digestable by humans

113. Modification of Cellulose
Cellulose Nitrate
guncotton
Pyroxylin
Partially nitrated photographic film
Cellulose Acetate
film

114. Cellulose fibre - Rayon

115. Biological Sugars and reactions

116. Membrane Carbohydrates
Membranes of animal plasma cells have large numbers of bound small carbohydrates to them.
these membrane-bound carbohydrates are part of the mechanism by which cell types recognize each other; they act as antigenic determinants
among the first discovered of these antigenic determinants are the blood group substances

117. ABO Blood Classification
at the cellular level, the biochemical basis for this classification is a group of relatively small membrane-bound carbohydrates

118. ABO Blood Classification
In the ABO system, individuals are classified according to four blood types: A, B, AB, and O

119. ‘Chemstrip Kit’ Blood glucose test for diabetics
Based on reaction of o-toluidine with glucose

120. Glucose Assay
Diabetes: A common analytical procedure in the clinical chemistry laboratory is the determination of glucose in blood, urine, or other biological fluid
The o-toluidine test is applied directly to serum, plasma, cerebrospinal fluid, and urine
samples as small as 20 L (microliters) can be used.
glucose reacts with 2-methylaniline (o-toluidine) in the presence of acetic acid to give an imine which has a blue-green color
the intensity of the absorption at 625 nm is proportional to the glucose concentration
Galactose, mannose, and to a lesser extent lactose and xylose also react with o-toluidine to give colored imines and, therefore, have the potential for false positive. 32

121. Glucose Assay
The glucose oxidase method is completely specific for D-glucose

122. Glucose Assay O2 is reduced to hydrogen peroxide H2O2
the concentration of H2O2 is proportional to the concentration of glucose in the sample
in one procedure, hydrogen peroxide is used to oxidize o-toluidine to a colored product, whose concentration is determined spectrophotometrically

123. Vitamin C - A monosaccharide?
Vitamin C, vital for life is a necessary part of our diet because we cannot synthesize it. (Most plants and animals except primates and guinea pigs can make their own Vitamin C).
It is needed to maintain health of dentine, cartilage, connective tissue and bone.
Recommended daily allowance ~45mg for adults (60mg if pregnant, 80mg if lactating).

124. Ascorbic Acid (Vitamin C)
L-Ascorbic acid (vitamin C) is synthesized both biochemically and industrially from D-glucose

125. Biosynthesis from Glucose

126. The outer viscous covering of fibers extending from a bacterium
Glycocalyx
The outer viscous covering of fibers extending from a bacterium
composition: The glycocalyx is usually a viscous polysaccharide and polypeptide slime.

127. Glycocalyx of Intestinal Epithelium
Note that some carbohydrates are covalently attached to membrane components, while others are secreted as extracellular matrix
Fig 16, The Cell, D.W. Fawcett (1981)

128. Glycocalyx of Lymphocyte

129. Diagram of Glycocalyx

130. Cellulose Polymer of D-glucose, found in plants.
Mammals lack the -glycosidase enzyme.
=>

131. Amylose Soluble starch, polymer of D-glucose.
Starch-iodide complex, deep blue.
=>

132. Amylopectin
Branched, insoluble fraction of starch.

133. Glycogen
Glucose polymer, similar to amylopectin, but even more highly branched.
Energy storage in muscle tissue and liver.
The many branched ends provide a quick means of putting glucose into the blood.

134. Chitin
Polymer of N-acetylglucosamine.
Exoskeleton of insects.
=>

135. Ribonucleosides
A -D-ribofuranoside bonded to a heterocyclic base at the anomeric carbon.
=>

136. Ribonucleotides
Add phosphate at 5’ carbon.

137. Nucleic Acids
=>
Polymer of ribofuranoside rings linked by phosphate esters.
Each ribose is bonded to a base.
Ribonucleic acid (RNA)
Deoxyribonucleic acid (DNA)

138. Structure of RNA
=>

139. Structure of DNA -D-2-deoxyribofuranose is the sugar.
Heterocyclic bases are cytosine, thymine (instead of uracil), adenine, and guanine.
Linked by phosphate ester groups to form the primary structure.

140. Base Pairings
=>

141. Double Helix of DNA Described by Watson and Crick, 1953.
Two complementary polynucleotide chains are coiled into a helix.

142. DNA Replication
=>

143. Additional Nucleotides
Adenosine monophosphate (AMP), a regulatory hormone.
Nicotinamide adenine dinucleotide (NAD), a coenzyme.
Adenosine triphosphate (ATP), an energy source.