Download 4. Chemical Properties of Monosaccharides

Chapter 15 Carbohydrates
15.4
Chemical Properties of
Monosaccharides
General, Organic, and Biological Chemistry
Copyright © 2010 Pearson Education, Inc.
1
Reducing Sugars
Reducing sugars
 are monosaccharides with a carbonyl group that
oxidizes to give a carboxylic acid
 undergo reaction with Benedict’s reagent (Cu2+) to
give the corresponding carboxylic acid
 include the monosaccharides glucose, galactose,
and fructose
General, Organic, and Biological Chemistry
Copyright © 2010 Pearson Education, Inc.
2
Oxidation of D-Glucose, a
Reducing Sugar
Glucose is oxidized to
a carboxylic acid.
Benedicts
reagent
General, Organic, and Biological Chemistry
Copyright © 2010 Pearson Education, Inc.
3
Reduction of Monosaccharides
The reduction of
monosaccharides
 involves the carbonyl
group
 produces sugar alcohols
called alditols
 such as D-glucose gives
D-glucitol, also called
D-sorbitol
General, Organic, and Biological Chemistry
Copyright © 2010 Pearson Education, Inc.
4
Learning Check
Write the products of the oxidation and reduction of
D-mannose.
O
C H
HO
H
HO
H
H
OH
H
OH
CH2OH
D-Mannose
General, Organic, and Biological Chemistry
Copyright © 2010 Pearson Education, Inc.
5
Solution
Write the products of the oxidation and reduction of
D-mannose.
CH2OH
HO
H
HO
H
Reduction
O
O
C H
C OH
HO
H
HO
H
Oxidation
HO
H
HO
H
H
OH
H
OH
H
OH
H
OH
H
OH
H
OH
CH2OH
D-Mannitol
General, Organic, and Biological Chemistry
CH2OH
D-Mannose
CH2OH
D-Mannonic acid
Copyright © 2010 Pearson Education, Inc.
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