Chapter 22 Carbohydrates
碳水化合物
ORGANIC CHEMISTRY
Chapter 22
22.1 Introduction
Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY
Chapter 22
Carbohydrates
Carbohydrates are everywhere in nature. They
occur in every living organism and are essential
to life.
The word carbohydrate derives historically from
the fact that glucose, has the molecular formula
C6H12O6 and was originally thought to be a
“hydrate of carbon”, C6(H2O)6.
Simple carbohydrates are also known as sugars
or saccharides, and the ending of the names of
most of sugars is –ose.
Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY
Chapter 22
22.1A Classification of Carbohydrates
Carbohydrates are usually defined as polyhydroxy
aldehydes and ketones or substances that hydrolyze to
yield polyhydroxy aldehydes and ketones.
Carbohydrates
Monosaccharides
The simplest
carbohydrates
Oligosaccharides
2-10
Monosaccharides
Polysaccharides
>10
Monosaccharides
Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY
Chapter 22
22.1B Photosynthesis and Carbohydrates
Metabolism
Carbohydrates are synthesized in green plants
by photosynthesis.
Carbohydrates acts as the chemical
intermediaries by which solar energy is stored
Light
and used to support life.
CO2
H2 O
Starch, Cellulose
O2
C6H12O6
Photosynthesis
Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY
Chapter 22
22.2 Monosaccharides
单糖
Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY
Chapter 22
22.2A Classification of Monosaccharides
The number of carbon atoms present in the molecule.
Whether they contain and aldehyde or keto group.
Aldoses
醛糖
Aldopentoses(戊醛糖)
Aldohexoses (己醛糖)
Monosaccharides
Ketopentoses (戊酮糖)
Ketoses
酮糖
Ketohexoses (己酮糖)
Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY
Chapter 22
22.2B D and L Designations of
Monosaccharides
CHO
CHO
CHO
H
OH
CH2OH
H
CH2OH
OH
H
O
H
OH
HO
H
OH
H
OH
H
OH
H
OH
H
OH
H
OH
HO
H
CH2OH
CH2OH
CH2OH
D-Glyceraldehyde D-Ribose
D-Glucose
D-Fructose
Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY
Chapter 22
D,L Sugars
CHO
CHO
HO
H
HO
H
OH
H
HO
OH
H
CHO
HO
H
H
OH
H
HO
H
H
OH
CH2OH
L-Glyceraldehyde
CH2OH
L-Glucose
CH2OH
D-Glucose
S-(-)-Glyceraldehyde
Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY
Chapter 22
22.2C Structural Formulas for
Monosaccharides
CHO
CHO
H
HO
OH
OH
H
CHO
HO
H
OH
OH
H
OH
OH
CH2OH
CH2OH
CH2OH
The carbonyl carbon is always placed either at the
top or near the top when showing the Fischer
projection of a carbohydrate.
Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY
Chapter 22
Configurations of Aldoses
CHO
H
OH
CH2OH
D-甘油醛
D-Glyceraldehyde
CHO
CHO
H
OH
HO
H
OH
H
CH2OH
D-赤藓糖
D-Erythrose
H
OH
CH2OH
D-苏阿糖
D-Threose
Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY
Chapter 22
Configurations of Aldopentoses
CHO
CHO
H
OH
HO
H
OH
H
OH
HO
H
OH
H
OH
H
CH2OH
D-核糖
D-Ribose
H
CHO
CH2OH
D-阿拉伯糖
D-Arabinose
H
CHO
OH
HO
H
H
HO
H
OH
CH2OH
D-木糖
D-Xylose
H
OH
CH2OH
D-来苏糖
D-Lyxose
Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY
Chapter 22
Configurations of Aldohexoses
CHO
CHO
H
CHO
H
CHO
H
OH
HO
OH
HO
H
H
OH
H
OH
HO
H
HO
H
H
OH
H
OH
H
OH
H
OH
H
OH
H
OH
H
OH
H
OH
CH2OH
D-阿洛糖
CH2OH
D-阿卓糖
CH2OH
D-葡萄糖
CH2OH
D-甘露糖
D-Allose
D-Altrose
D-Glucose
D-Mannose
CHO
CHO
H
OH
HO
H
OH
H
HO
H
H
OH
CH2OH
HO
H
H
CHO
H
CHO
OH
HO
H
OH
HO
H
HO
H
H
HO
H
HO
H
OH
CH2OH
H
OH
CH2OH
H
OH
CH2OH
D-古罗糖
D-艾杜糖
D-半乳糖
D-塔罗糖
D-Gulose
D-Idose
D-Galactose
D-Talose
Department of Chemistry, Xiamen University