Carbohydrates

(Saccharides,Sugars)

monosaccharides.

Carbohydrates (saccharides)-

one of a group of organic compounds based on the general formula Cx(H2O)y. Carbohydrates perform many vital roles in living organisms . Sugar, notably glucose, their derivatives are essential intermediates in the conversion of food energy. All sugars typically have a sweet taste. Simple sugars are called

monosaccharides.

Carbohydrates. Classification

1.Monosaccharides

2. Disaccharides (2) 3.Oligosaccharides (3-10)

4. Polysaccharides (more than 10)

MonosaccharidesMonosaccharides—are heterofunctional

compounds with oxo- and a few hydroxy -groups.

That is polyhydroxyaldehydes and

polyhydroxyketones.

Monosaccharides.

(CHOH)n

CH2OH

CH O

(CHOH)n

CH2OH

CH2OH

C O

Aldosen=1–8

Кеtosen=1–7

Monosaccharides. The aldohexoses have four chiral centers for a total of 16 possible aldohexose stereoisomers (24). The D/L configuration is based on the orientation of the hydroxyl at position 5, and does not refer to the direction of optical activity.

• D-Galactose

D-Glucose D-Mannose D-Galactose 6

Ketohexoses.The ketohexoses have 3 chiral centers and therefore eight possible stereoisomers (23). Of these, only the four D-isomers are known to occur naturally:

CH2OH CH2OH CH2OH CH2OH | | | | C=O C=O C=O C=O | | | | HC-OH HO-CH HC-OH HO-CH | | | | HC-OH HC-OH HO-CH HO-CH | | | | HC-OH HC-OH HC-OH HC-OH | | | | CH2OH CH2OH CH2OH CH2OH

D-psicose D-fructose D-sorbose D-tagatose 7

Monosaccharides. Aldopentoses The aldopentoses have three chiral centers and therefore eight different stereoisomers are possible.

8

Ribose Deoxyribose

Monosaccharides D-,L-classification

Monosaccharides

D-Glucose enantiomers L-Glucose

Monosaccharides. Mutarotation. Tautomerism.

Mutarotation. The aldehyde and ketone functional groups in these carbohydrates react with neighbouring hydroxyl functional groups to form intramolecular hemiacetals and hemiketals, respectively. The resulting ring structure is related to pyran, and is termed a pyranose. The ring spontaneously opens and closes, allowing rotation to occur about the bond between the carbonyl group and the neighbouring carbon atom, yielding two distinct configurations (α and β). This process is termed mutarotation. Hexose sugars can form dihexose sugars with a condensation reaction to form a 1,6-glycosidic bond.

The light mutarotation – change of optical activity with time as a result of tautomerism.

Monosaccharides Cyclic formulas.

Monosaccharides. Hawars’s Formulas

Monosaccharides. Cyclic formulas

14

Monosaccharides. Cyclic formulas.

Monosaccharides. Cyclic formulas.

H

HOH

H

HO

H

CH2OH

HO

H

OH

O

H

HH

OH

HO

H

CH2OH

HO

H

OH

O

-anomer -anomer

Chair conformations of D-Glucopyranose

Monosaccharides. Tautomerism.

Monosaccharides. Cyclic formulas.

Monosaccharides. Chemical properties.Glycosides.

Monosaccharides. Chemical properties.Glycosides.

Monosaccharides. Chemical properties.Eters.

Monosaccharides. Chemical properties.Esters.

Monosaccharides. Chemical properties.Oxidation.

Monosaccharides. Chemical properties.Oxidation.

CHO

OHH

HHO

OHH

OHH

CH2OH

Br2, H2O

COOH

OHH

HHO

OHH

OHH

CH2OH

CaCO3

COO-

OHH

HHO

OHH

OHH

CH2OH2

Ca+2

Monosaccharides. Chemical properties. Oxidation.

Gluconic acid

Monosaccharides. Chemical properties. Oxidation.

With Nitric acd

26

Glucaric acid

Monosaccharides. Chemical properties.Reduction.

Monosaccharides.Chemical properties.Reduction.

29

Monosaccharides.

A disaccharide or biose is the carbohydrate formed

when two monosaccharides undergo a condensation

reaction which involves the elimination of a small

molecule, such as water, from the functional groups

only. Like monosaccharides, disaccharides also

dissolve in water, taste sweet and are called sugars.

Disaccharides.

Disaccharides. Non-reducing Disaccharide.

Disaccharides. Reducing Disaccharide.

Disaccharides. Reducing Disaccharide.

Disaccharides. Reducing Disaccharides.

Disaccharides . Reducting Disaccharide.

Disaccharides .

Polysaccharides. Homopolysaccharides

Cellulose

Polysaccharides.

Polysaccharides.

Hydrocarbon RadicalEter

–CH3 methylcellulose

–CH2COONa carboximethylcellulose

–CH2CH2N(C2H5)2 diethylaminethylcellulose

Ester

–C(O)CH3 cellulose acetate

–C(O)CH2CH2CH3 cellulose butirate

–C(O)CH3 и –C(O)CH2CH2CH3

cellulose acetylbutyrate

Polysaccharides.

Polysaccharides.

Polysaccharides.

Spiral of Amilose

Polysaccharides.

Complex of Amilose and Iodine

Polysaccharides.

Macromolecula of Amilopectine

Polysaccharides.

Glycogen Structure Segment

Polysaccharides.

Polysaccharides.

Polysaccharides.

Polysaccharides.