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Greek sakcharon= sugar

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Carbohydratespolyhydroxyaldehydes or polyhydroxy-

ketones of formula (CH2O)n, or compounds that can behydrolyzed to them. (aka sugars or saccharides)

Monosaccharidescarbohydrates that cannot be hydrolyzed

to simpler carbohydrates; eg. Glucose or fructose.

Disaccharidescarbohydrates that can be hydrolyzed intotwo monosaccharide units; eg. Sucrose, which is hydrolyzed

into glucose and fructose.

Oligosaccharidescarbohydrates that can be hydrolyzed into

a few monosaccharide units.

Polysaccharidescarbohydrates that are are polymeric

sugars; eg Starch or cellulose.

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Aldosepolyhydroxyaldehyde, eg glucose

Ketosepolyhydroxyketone, eg fructose

Triose, tetrose, pentose, hexose, etc.carbohydrates that

contain three, four, five, six, etc. carbons per molecule(usually five or six); eg. Aldohexose, ketopentose, etc.

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Reducing sugara carbohydrate that is oxidized by Tollens,

Fehlings or Benedicts solution.

Tollens: Ag+ Ag (silver mirror)

Fehlings or Benedicts: Cu3+ (blue) Cu2+ (red ppt)

These are reactions of aldehydes and alpha-hydroxyketones.

Allmonosaccharides (both aldoses and ketoses) and most*

disaccharides are reducing sugars.

*Sucrose (table sugar), a disaccharide, is not a reducing sugar.

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Glucose (a monosaccharide)

Plants:photosynthesis

chlorophyll

6 CO2 + 6 H2O C6H12O6 + 6 O2

sunlight (+)-glucose

(+)-glucose starch or cellulose

respiration

C6H12O6 + 6 O2 6 CO2 + 6 H2O + energy

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Animalsplant starch (+)-glucose

(+)-glucose glycogen

glycogen (+)-glucose(+)-glucose fats or aminoacids

respiration

(+)-glucose + 6 O2 6 CO2 + 6 H2O + energy

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OH

CHO

H

CH2OH

H

CHO

HO

CH2OH

D-(+)-glyceraldehyde L-(-)-glyceraldehyde

glyceraldehyde

an aldotriose

CH2CHCH O

OH OH

*

D & L are used to relate configuration of the chiral center

most removed from the reducing group ( C=O ). If the -OHis on the right in the Fischer projection, then it is D, if the -OHis on the left, then it is L

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CHO

H OH

CH2OH

H OH

aldotetrosesCH2CHCHCH O

OH OHOH

* *

CHO

HO H

CH2OH

HO H

CHO

H OH

CH2OH

HO H

CHO

HO H

CH2OH

H OH

D-erythrose L-erythrose

L-threose D-threose

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(+)-glucose? An aldohexose

Emil Fischer (1902)Four chiral centers, 24 = 16 stereoisomers

CHO

CH2OH

OH?

CH2CHCHCHCHCH O

OH OHOHOHOH

* * * *

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CHO

OHH

OHH

OHH

OHH

CH2OH

CHO

HHO

OHH

OHH

OHH

CH2OH

CHO

OHH

HHO

OHH

OHH

CH2OH

CHO

HHO

HHO

OHH

OHH

CH2OH

CHO

OHH

OHH

HHO

OHH

CH2OH

CHO

HHO

OHH

HHO

OHH

CH2OH

CHO

OHHHHO

HHO

OHH

CH2OH

CHO

HHOHHO

HHO

OHH

CH2OH

CHO

HO H

HO H

HO H

HO H

CH2OH

CHO

H OH

HO H

HO H

HO H

CH2OH

CHO

HO H

H OH

HO H

HO H

CH2OH

CHO

H OH

H OH

HO H

HO H

CH2OH

CHO

HO H

HO H

H OH

HO H

CH2OH

CHO

H OH

HO H

H OH

HO H

CH2OH

CHO

HO HH OH

H OH

HO H

CH2OH

CHO

H OHH OH

H OH

HO H

CH2OH

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Ruff degradationa series of reactions that removes the

reducing carbon ( C=O ) from a sugar and decreases the

number of chiral centers by one; used to relate configuration.

CHO

H OH

CH2OH

H OH

CO2H

H OH

CH2OH

H OH

Br2

H2O

CO2

H OH

CH2OH

H OH

Ca2+

H2O2

Fe3+

CHO

CH2OH

H OH

D-(+)-glyceraldehyde

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Kiliani-Fischer synthesis. A series of reactions that extends the

carbon chain in a carbohydrate by one carbon and one chiral

center.

CHO

H OH

CH2OH

HCN

C

H OH

CH2OH

H OH

C

HO H

CH2OH

H OH+

N N

H+,H2O

COOH

H OH

CH2OHH OH

COOH

HO H

CH2OHH OH

diastereomersseparable

C

H OH

H2C

H OH

O

O

lactone

Na(Hg)

CHO

H OH

CH2OH

H OH

-H2O

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Epimersstereoisomers that differ only in configuration about

one chiral center.

CHO

OHH

HHOOHH

OHH

CH2OH

D-glucose

CHO

HHO

HHOOHH

OHH

CH2OH

D-mannoseepimers

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CHO

OHH

HHO

OHH

OHH

CH2OH

(+)-glucose

Exists only in solution. There are two

solids:

-glucose m 146o [] = +112.2

-glucose m 150o [] = +17.5

In water each mutarotates to an

equilibrium with [] = +52.7

(63.6% / 36.4% )

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CHO

OHHHHO

OHH

OHH

CH2OH

OH

HO

H

HO

H

OHOHH

H

OH

OH

HO

H

HO

H

HOHH

OH

OH

alpha-(+)-glucose beta-(+)-glucose

OH

OH

OH

HH

OHH

OH

CH2OHOH

OH

H

OH

H

OHH

OH

CH2OH

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RC

H

O

+ R'OH R C H

OH

OR'

R C H

OR'

OR'

hemiacetalgeminalether/alcoholreducing!

acetalgeminaldiethernon-reducing!

Addition of alcohols to aldehydes/ketones:

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CHO

OHH

HHO

OHHOHH

CH2OH

O

H

HO

HHO

H

OHOHH H

OH

O

H

HO

HHO

H

HOHH OH

OH

nucleophilic addition of -OH on carbon 5 to the aldehyde functional group

CHO

OHH

HHO

OHHOHH

CH2OH

CH

OHH

HHO

OHH

HHOH2C

OH

O

H

HO

H

HO

H

OHOHH

H

OH

O

O

H

HO

H

HO

H

HOHH

OH

OH

rotate C-5 OH to rear

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O

H

HO

H

HO

H

HOHH

OH

OH

O

H

HO

H

HO

H

OHOHH

H

OH

hemiacetal

4H-Pyran

OD-glucopyranoses

alpha beta

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OH

H

HH OH

HO HO

H

HOHO

H

OH

HH OH

HO HO

H

HOHO

O

furan

alpha furanose form beta furanose form

D-glucofuranoses

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O

H

HO

H

HO

H

HOHH

OH

OH

O

H

HO

H

HOH

OHOHH

H

OH

alpha beta

anomers - epimers at C-1

chair conformations - alpha has one group axialbeta has all groups equatorialmutarotation in solution to 63.6% beta/36.4% alpha

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CH2OH

O

HHO

OHH

OHH

CH2OH

D-fructose

CH2OH

OH

H

CH2OH

OH H

H OHO

beta-D-fructofuranose

OH

CH2OH

H

CH2OH

OH H

H OHO

alpha-D-fructofuranose

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O

H

HO

H

HO

H

HOHH

OH

OH

CH3OH

HCl

OH

HO

H

HO

H

HOHH

OCH3

OH

acetal

(glucoside - glucose acetal)non-reducing, does not muta-rotate

methyl beta-D-glucoside

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Disaccharides:

(+)-maltose malt sugar

two glucose units (alpha)

(+)-cellobiose

two glucose units (beta)

(+)-lactose milk sugar

galactose & glucose

(+)-sucrose table sugar

glucose & fructose

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(+)-maltose

O

H

H

HO

H

HOHH

OH

OH

O

H

HO

H

HO

H

OHHH

OH

O

two glucose unitsalpha C-1 to C-4

reducing sugar

O

H

HO

H

HO

H

HOHH

OH

O

H

O

H

HO

H

HOHH OH

OH

(+)-cellobiose

two glucose units

beta C-1 to C-4

reducing sugar

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O

H

HO

H

HO

H

OHHH

OH

glucose alpha C-1

to beta C1 fructose

O

HO

H

H

HO

H

HOHH

OH

O

H

O

H

HO

H

HOHH

OH

OH galactose beta C-1to C-4 glucose

reducing sugar(+)-lactose

OO

CH

2OH

CH2OH

H

H

OH

HO

H

(+)-sucrose

acetalnon-reducing

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Polysaccharides

starch

cellulose

Starch 20% amylose (water soluble)

80% amylopectin (water insoluble)

amylose + H2O (+)-maltose

(+)-maltose + H2O (+)-glucose

starch is a poly glucose (alpha-glucoside to C-4)

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

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O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

CH2

O

Amylopectin + H2O (+)-maltose

(+)-maltose + H2O (+)-glucose

Also a polyglucose, but branched every 20-25 units:

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Cellulose is a polyglucose with a beta-linkage:

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O