Chapter 17
Carbohydrates
（糖，碳水化合物）
Ref: Wade, chapter 23
曾昭琼，第十九章
Carbohydrates (糖，碳水化合物)
D-glucose (葡萄糖)
H
HO
H
H
CHO
(R)
OH
(S)
H
(R)
OH
(R)
OH
CH2OH
H
HO
H
H
CHO
OH
H
OH
OH
CH2OH
D-fructose (果糖)
CH2OH
C O
(S)
HO
H
(R)
H
OH
(R)
H
OH
CH2OH
CH2OH
C O
HO
H
H
OH
H
OH
CH2OH
Sugars (糖)
They have the molecular formulas Cn(H2O)n
Carbohydrates (糖，碳水化合物)
Polyhydroxyaldehydes, polyhydroxyketones, and
compounds that can be hydrolyzed to them are classified
as carbohydrates （多羟基醛、多羟基酮及凡是能水解得
到多羟基醛或多羟基酮的化合物均是碳水化合物）
葡萄糖(glucose)、果糖(fructose)、半乳糖(galactose)
蔗糖(sucrose)、麦芽糖(maltose)、乳糖(lactose)
淀粉(starch)、纤维素(cellulose)
Classification of carbohydrates
 monosacharides （单糖）★: simple sugar
葡萄糖(glucose)、果糖(fructose)、半乳糖(galactose)
 disaccharides （二糖）
蔗糖(sucrose)、麦芽糖(maltose)、乳糖(lactose)
 oligosaccharides （寡糖）
 polysaccharides （多糖）
淀粉(starch)、纤维素(cellulose)
Monosaccharides
单糖
1. Classification of Monosaccharides
 Polyhydroxy aldehydes are aldoses （醛糖）
 Polyhydroxy ketones are ketoses （酮糖）





trioses 三碳糖，丙糖
tetroses 四碳糖，丁糖
pentoses 五碳糖，戊糖
hexoses 六碳糖，己糖
heptoses 七碳糖，庚糖
aldohexose
己醛糖
ketohexose
己酮糖
 D/L: D and L notations are used to describe the
configurations of carbohydrates (根据构型分类)
CHO
CHO
H
OH
CH2OH
D-(+)-Glyceraldehyde
D-(+)-¸ÊÓÍÈ©
H
HO
H
H
CHO
OH
H
OH
OH
CH2OH
D-glucose
D-葡萄糖
HO
H
CH2OH
L-(-)-Glyceraldehyde
L-(-)-¸ÊÓÍÈ©
HO
H
HO
HO
CHO
H
OH
H
H
CH2OH
L-glucose
L-葡萄糖
2. Structures of monosaccharides
Relative configuration 相对构型
D- /L- ：
erythreo- /threo- 赤式/苏式
Absolute configuration 绝对构型
R- /S-
Open-chain structure 开链结构
Cyclic structure 环状结构
ref: 图19-1
or figure 23-3
Family tree of
D-aldoses
D-甘油醛
D-苏阿糖
D-赤藓糖
D-核糖
D-葡萄糖
D-树胶糖
阿拉伯糖
D-甘露糖
D-木糖
D-半乳糖
D-异木糖
erythreo赤式
Diastereomer
非对映体
threo苏式
epimers （差向异构体）
具有三个或三个以上手性中心的化合物，若只有
一个手性中心不同，其它都相同，则互称为差向异
构体（epimers）
Cyclic Structures of Monosaccharides
----Hemiacetal（半缩醛） Formation
CHO
H
CH2OH
O
H
H
OH
H
H
HO
OH
OH
H
OH
Haworth formulas
OH
HO
HO
OH
H
H
H
OH
H
OH
CH2OH
CH2OH
O
H
H
OH
H
OH
H
OH
OH
α-D-(+)-glucopyranose
OH
Haworth formulas
Anomeric carbon
异头碳，端基碳
O
OH
HO
HO
OH
O
OH
OH
β-D - (+)-glucopyranose
anomer 端基（差向）异构体
D-葡萄糖(glucose)
1
CHO
2
H C OH
3
HO C H
4
H 5C OH
H C OH
6
CH2OH
HOH2C
HO
HO
O
OH
OH
除1-位碳外，其它
碳上的羟基及羟甲
基均处在平伏键上。
Drawing cyclic monosaccharides
1
CHO
2
H C OH
3
HO C H
4
H 5C OH
H C OH
6
CH2OH
6CH2OH
H
O
5
H
H
C
4
H
OH
1
OH 3
2
* OH
H
OH
¦Á-D-(+)-Glucopyranose
(¦Á-D-(+)-ßÁà«(ÐÍ)ÆÏÌÑÌÇ)
H
6
CH2OH
5
OH
OH
OH 3
H
H
4
H
4
2
OH
6CH2OH
O
5
H
H
OH
OH 3
H
D-葡萄糖
(glucose)
CHO
1
H
H
CH
1
6CH2OH
O
2
OH
Open-chain form of D-glucose
(¿ªÁ´ÐÍD-ÆÏÌÑÌÇ£©
5
H
OH
OH 3
H
H
4
* OH
O
H
2
OH
C
1
H
¦Â-D-(+)-Glucopyranose
(¦Â-D-(+)-ßÁà«(ÐÍ)ÆÏÌÑÌÇ)
把羰基碳放在最右侧，把环中氧原子放在右后方。
6CH2OH
H
O
5
H
H
C
4
H
OH
1
OH 3
2
* OH
H
OH
HOH2C
O
HO
HO
OH
OH
trans-, αα-D-(+)-glucopyranose
H
4
6CH2OH
O
5
H
H
OH
OH 3
H
* OH
C
1
2
OH
H
HOH2C
O
HO
HO
OH
OH
cis-, β β-D - (+)-glucopyranose
b-D-glucose is the predominant form at
equilibrium
D-glucopyranose
D-吡喃葡萄糖
1
CHO
2
H C OH
3
HO C H
4
H 5C OH
H C OH
6
CH2OH
α-D-glucopyranose
α-D-吡喃葡萄糖
β-D-glucopyranose
β-D-吡喃葡萄糖
D-ribofuranose
D-呋喃核糖
α-D-ribofuranose
α-D-呋喃核糖
β -D-ribofuranose
β -D-呋喃核糖
Note …
• If an aldose can form a five- or six-membered ring, it
will exist predominantly as a cyclic hemiacetal
• Six-membered rings are called pyranoses
• Five-membered rings are called furanoses


Haworth projections allow us to see the relative
orientation of the OH groups in the ring.
b- sugar is the predominant form at equilibrium.
D-fructose(果糖)
mutarotation (变旋现象)：a property of anomers
CHO
OH
H
H2C
HO
HO
O
OH
OH
¦Á-D-(+)-Glucopyranose
(¦Á-D-(+)-ßÁà«(ÐÍ)ÆÏÌÑÌÇ)
(mp, 146¡æ [a]D25 = +1120)
HO
OH
OH
H
H
OH
H
OH
H2C
HO
HO
(¿ªÁ´ÐÍD-ÆÏÌÑÌÇ£©
OH
OH
CH2OH
Open-chain form
of D-glucose
O
¦Â-D-(+)-Glucopyranose
(¦Â-D-(+)-ßÁà«(ÐÍ)ÆÏÌÑÌÇ )
(mp, 150¡æ [a]D25 = +18.70)
At equilibrium, [α]D25 = +52.6° , including
α- 36%
β- 64%
3. Reactions of monosaccharides
-C=O, -OH
• (1) Side reactions in base: epimerization; enediol rearrangement
• (2) Reduction: NaBH4 ; H2/catalyst, forming alditols (糖醇)
• (3) Oxidation:
•
Bromine water (Br2-H2O); forming aldonic acid (glyconic acid,
糖酸)
•
HNO3; forming aldaric acid (糖二酸)
•
Tollens test; Feilling’s reagent;
• (4) Formation of glycosides
• (5) Etherification
• (6) Acylation: ester formation
• (7) Reaction with phenylhydrazines: osazones (糖脎) formation
• (8) Chain shortening: the Ruff degradation
• (9) Chain lengthening: the Kiliani-Fischer synthesis
(1) Side reactions in base:
--------epimerization; enediol rearrangement
(差向异构化)；(烯二醇重排)
23-8
epimerization
CHO
H
HO
CHO
OH
OH
H
H
HO
H
H
OH
H
OH
H
OH
H
OH
CH2OH
CH2OH
D-glucose
D-葡萄糖
HOH2C
HO
HO
HO
HOH2C
O
OH
D-mannose
D-甘露糖
OH
HO
HO
OH
O
OH
D-fructose
D-果糖
D-glucose
D-葡萄糖
enediol rearrangement
D-mannose
D-甘露糖
(2) Reduction of Monosaccharides
23-9
The carbonyl of aldoses and ketoses can be reduced by
the carbonyl-group reducing agents to form alditols(糖醇)
CHO
HOH2C
HO
HO
H
O
OH
OH
HO
OH
H
H
NaBH4
OH or H2/Ni
H
OH
CH2OH
D-Glucose
CH2OH
H
HO
OH
H
H
OH
H
OH
CH2OH
D-Glucitol
(D-ÆÏÌÑÌÇ´¼£©
(3) Oxidation of monosaccharides; reducing sugars
23-10
A) Br2-H2O
The aldehyde groups can be oxidized
Ketones and alcohols cannot be oxidized by Br2
Br2-H2O can be used to determine aldehydes and ketones
B) Nitric acid (HNO3)
CH2OH
COOH
O
HO
H
HNO3
HO
H
H
OH
H
OH
H
OH
H
OH
CH2OH
COOH
C) Tollens test: Ag(NH3)2+
CHO
H
HO
COOH
OH
H
Ag(NH3)2
+
H
HO
OH
H
H
OH
H
OH
H
OH
H
OH
CH2OH
CH2OH
CH2OH
COOH
O
HO
H
+ Ag mirror
H
Ag(NH3)2+
HO
COOH
OH
H
+
HO
H
HO
H
H
OH
H
OH
H
OH
H
OH
H
OH
H
OH
CH2OH
CH2OH
CH2OH
• Sugars that reduce Tollens reagent to give a silver mirror are
called reducing sugar(还原性糖).
D) Periodic acid (HIO4) cleavage of sugars
H
H
C
OH
H +
O
H C OH
H
C
OH + 2 HIO4
H
C
OH
H
+
H
O
H
O
1
H
HO
H
H
C
formaldehyde
(¼×È©)
O
H
1
H C OH
+
OH
OH
OH
6 CH2OH
formaldehyde
(¼×È©)
O
H
H
formic acid
(¼×Ëᣩ
+ 5 HIO4
formic acid
(¼×Ëᣩ
O
4 H C OH
H
+
C O
H 6
formic acid
(¼×Ëᣩ
formaldehyde
(¼×È©)
(4) Formation of glycosides (糖)苷
The acetal (or ketal) of a sugar is called a glycoside.
CHO
H
HO
OH
OH
H
H
OH
H
OH
O
HO
HO
OH
CH3OH
HCl
OH
CH2OH
D-(+)-Glucose
OH
HO
HO
OH
O
+
OH
OCH3
methyl α-D-glucopyranoside
(甲基-α-D-(+)-吡喃葡萄糖苷 )
(mp, 165℃ [α]D25 = +158°)
HO
HO
O
OCH3
OH
methyl β-D-Glucopyranoside
(甲基- β-D-(+)-吡喃葡萄糖苷 )
(mp, 107℃ [α]D25 = -33°)
Nonreducing sugars 非还原性糖
Mechanism of Glycoside Formation
Formation of an N-Glycoside
(5) Etherification 醚化
OH
OCH3
CH3__OSO3CH3
O
HO
HO
OH
-OH
H3CO
H3CO
OH
Methyl 2,3,4,6-tetra-O-methyl-β-Dglucopyranoside
OCH3
CHO
OCH3
H3O+
O
OCH3 H2O
OCH3
OCH3
OCH3
Reagents:
CH3OSO3CH3-NaOH;
CH3I-Ag2O
H3CO
H3CO
O
H3CO
H3CO
H
O
H3CO
OH
OCH3
OCH3
H
H
OCH3
H
OH
2,3,4,6-tetra-O-methyl-D-glucose
(2,3,4,6-四-O-甲基葡萄糖）
CH2OCH3
(6) Acylation: ester formation
五乙酰葡萄糖
Reagents:
RCOCl or RCOOCOR, base;
(7) Reaction with phenylhydrazines:
------osazones (糖脎) formation
osazones (糖脎)
HO
HO
H
H
CHO
H
H
OH
OH
CH2OH
D-mannose
D-甘露糖
3PhNHNH2
HC NNHPh
C NNHPh
HO
H
H
OH
H
OH
CH2OH
3PhNHNH2
CH2OH
O
HO
H
H
OH
H
OH
CH2OH
D-fructose
D-果糖
(8) Chain shortening: the Ruff degradation(降级)
The Ruff degradation is used mainly for determination
and synthesis of new sugars.
(9) Chain lengthening: the Kiliani-Fischer synthesis
This method is used for synthesis of
new sugars.
4. Determination of the structure of monosaccharides
(1) Fisher’s proof of the configuration of glucose
D-glucose
degradation
degradation
D-arabiose
D-mannose
HNO3
Optically active
product
COOH
H
OH
H
OH
H
OH
COOH
COOH
HO
H
H
OH
H
OH
COOH
D-erythrose
HNO3
Meso-tartaric acid
COOH
H
OH
H
OH
COOH
(2) Determination of Ring Size
Approach 1
The size of the ring can be determined from the structure
of the open-chain form
Approach 2
An acetal of the monosaccharide is oxidized with excess
HIO4
3
+ CH3OH + HCOOH
Problem:
H
H
HIO4
HOHO
O
HO
H
H
OCH3
OH
H
H3O+
5. Disaccharides 二糖
Cellobiose
纤维二糖
Maltose
麦芽糖
Lactose
乳糖
1,1’- link
Sucrose
蔗糖
Which is a nonreducing sugar?
6. Polysaccharides
starch（淀粉）
Amylose
直链淀粉
Amylopectin
支链淀粉
cellulose（纤维素）
H
H
CH2OH
O
H
H
OH
CH2OH
O
H
H
OH
O
C
O
H
H
OH
H
H
OH
The glycosidic linkages are b , 1: 4
n
Blood type（血型） is determined by the nature of the sugar
bound to the protein on the surface of red blood cells
7. Nuleic acids 核酸
核蛋白
nucleoprotein
核酸（RNA，DNA）
Nucleic acid
蛋白质
protein
核苷酸（单体）
Nucleotide
磷酸
Phosporic acid
核苷
Nucleoside
戊糖(2种:核糖, 脱氧核糖)
pentose
碱基(5种)
base
戊糖 pentose
HOH2C
H
O
H
HO
HOH2C
OH
H
H
O
H
HO
H
OH
OH
H
H
H
脱氧核糖 deoxyribose
核糖 ribose
核苷
Nucleoside
base
HO
H
O
H
H
H
OH OH
核糖核苷
ribonucleosides
base
HO
H
O
H
H
H
OH H
脱氧核糖核苷
deoxyribonucleosides
常见碱基(base)
O
OH
O
NH
N
N
OH
N
H
H2N
H3C
H2N
N
H
N
鸟嘌呤 guanine (G)
NH
N
N
H
OH
O
胸腺嘧啶 thymine(T)
NH2
NH2
N
N
N
N
H
N
N
N
O
OH
N
N
HN
O
脲嘧啶 uracil (U)
H3C
OH
OH
N
H
胞嘧啶 cytosine (C)
NH
NH2
N
HN
N
N
H
N
N
N
O
腺嘌呤 adenine (A)
N
H
在RNA中存在下列四种核苷：
NH2
N
CH2OH
O
OH
脲苷
N
OH
N
NH
O
CH2OH
O
OH
胞苷
N
OH
O
NH2
O
O
CH2OH
O
OH
N
OH
腺苷
N
N
N
CH2OH
O
OH
N
NH
N
NH2
OH
鸟苷
规则：嘧啶的1位和嘌呤环的9位分别和核糖的苷羟基相连
核苷酸 ribonucleic acid
核苷的磷酸酯：核苷的3位或5位的羟基和磷酸结合
O
O
HO
P
OH
N
OCH2
O
OH
N
H
NH
N
O
N
NH2
N
H
HO
H
O
H
H
H
O
OH
O P OO-
NH
N
NH2
O
O
O
P
O
H
O
DNA
deoxyribonuleic acids
base
H
H
H
H
O
O
P
O
H
O
base
O
H
H
H
H
O
O
P
O
H
O
base
O
H
H
H
H
O
O
P
O
H
O
base
O
H
OH
H
H
H
Contents
•
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•
Classification of carbohydrates
Monosaccharides ★
★ Classification
★ Structure
chain: configuration: D,L-; erythro/threo;
cyclic structure: α-,β-; mutarotation
★ Reactions
oxidation: tollen’s reagent, Br2-H2O; HNO3; HIO4
reduction: NaBH4
formation of osazones
formation of glycosides
acylation
etherification
chain shorting (degradation) and lengthening
Fischer’s proof of the configuration of glucose
determination of ring size
Disaccharides
Polysaccharides
Nucleic acids
Assignments
• 23-54, 57, 59, 63, 66, 67，69