σακχαρων Greek “sakcharon” = sugar

σακχαρων Greek “sakcharon” sugar

Carbohydrates – polyhydroxyaldehydes or polyhydroxyketones of formula (CH2O)n, or compounds that can be hydrolyzed to them. (aka sugars or saccharides) Monosaccharides – carbohydrates that cannot be hydrolyzed to simpler carbohydrates; eg. Glucose or fructose. Disaccharides – carbohydrates that can be hydrolyzed into two monosaccharide units; eg. Sucrose, which is hydrolyzed into glucose and fructose. Oligosaccharides – carbohydrates that can be hydrolyzed into a few monosaccharide units. Polysaccharides – carbohydrates that are are polymeric sugars; eg Starch or cellulose.

Aldose – polyhydroxyaldehyde, eg glucose Ketose – polyhydroxyketone, 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.

Reducing sugar – a carbohydrate that is oxidized by Tollen’s, Fehling’s or Benedict’s solution. Tollen’s: Ag Ag (silver mirror) Fehling’s or Benedict’s: Cu3 (blue) Cu2 (red ppt) These are reactions of aldehydes and alpha-hydroxyketones. All monosaccharides (both aldoses and ketoses) and most* disaccharides are reducing sugars. * Sucrose (table sugar), a disaccharide, is not a reducing sugar.

Glucose (a monosaccharide) Plants: photosynthesis chlorophyll 6 CO2 6 H2O ( )-glucose sunlight C6H12O6 6 O2 ( )-glucose starch or cellulose respiration C6H12O6 6 O2 6 CO2 6 H2O energy

Animals plant starch ( )-glucose ( )-glucose glycogen glycogen ( )-glucose ( )-glucose fats or aminoacids respiration ( )-glucose 6 O2 6 CO2 6 H2O energy

glyceraldehyde an aldotriose CHO H OH CH2OH D-( )-glyceraldehyde * CH2CHCH O OH OH CHO HO H CH2OH L-(-)-glyceraldehyde D & L are used to relate configuration of the chiral center most removed from the reducing group ( C O ). If the -OH is on the right in the Fischer projection, then it is D, if the -OH is on the left, then it is L

aldotetroses * * CH2CHCHCH O OH OHOH CHO H OH H OH CH2OH CHO HO H HO H CH2OH D-erythrose L-erythrose CHO H OH HO H CH2OH CHO HO H H OH CH2OH L-threose D-threose

( )-glucose? An aldohexose Emil Fischer (1902) * * * * CH2CHCHCHCHCH O OH OHOHOHOH Four chiral centers, 24 16 stereoisomers CHO OH? CH2OH

H H H H CHO OH OH OH OH CH2OH HO HO H H CHO H H OH OH CH2OH H HO HO H CHO OH H H OH CH2OH HO HO HO HO CHO H H H H CH2OH H H HO HO CHO OH OH H H CH2OH HO H H HO CHO H OH OH H CH2OH HO H H H CHO H OH OH OH CH2OH H H HO H CHO OH OH H OH CH2OH HO HO HO H CHO H H H OH CH2OH H HO HO HO CHO OH H H H CH2OH HO HO H HO CHO H H OH H CH2OH H H H HO CHO OH OH OH H CH2OH H HO H H CHO OH H OH OH CH2OH HO H HO H CHO H OH H OH CH2OH HO H HO HO CHO H OH H H CH2OH H HO H HO CHO OH H OH H CH2OH

Ruff degradation – a 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 H OH CH2OH Br2 H2O CO2H H OH H OH CH2OH Ca2 CHO H OH CH2OH D-( )-glyceraldehyde H2O2 Fe3 CO2 H OH H OH CH2OH

Kiliani-Fischer synthesis. A series of reactions that extends the carbon chain in a carbohydrate by one carbon and one chiral center. CHO HCN H OH CH2OH C N C N COOH COOH HO H H OH H ,H2O H OH HO H H OH H OH H OH H OH CH2OH CH2OH CH2OH CH2OH CHO H OH H OH CH2OH Na(Hg) O C H OH H OH H2C O lactone diastereomers separable -H2O

Epimers – stereoisomers that differ only in configuration about one chiral center. H HO H H CHO OH H OH OH CH2OH D-glucose HO HO H H CHO H H OH OH CH2OH D-mannose epimers

H HO H H CHO OH H OH OH CH2OH ( )-glucose Exists only in solution. There are two solids: α-glucose m 146o [α] 112.2 β-glucose m 150o [α] 17.5 In water each mutarotates to an equilibrium with [α] 52.7 (63.6% β / 36.4% α)

H OH H HO H H HO HO HO H H H OH OH CHO OH H OH OH CH2OH H OH HO HO H H H OH OH H OH H beta-( )-glucose CH2OH O OH H H alpha-( )-glucose H HO OH CH2OH O OH OH H H OH H OH OH

Addition of alcohols to aldehydes/ketones: R O C H R'OH OH R C H OR' hemiacetal geminal ether/alcohol reducing! OR' R C H OR' acetal geminal diether non-reducing!

H OH HO HO HO H H OH H OH H HO H H CHO OH H OH OH CH2OH H OH HO HO HO H H H OH OH nucleophilic addition of -OH on carbon 5 to the aldehyde functional group H OH H HO H H CHO OH H OH OH CH2OH H HO H HOH2C CH O OH H OH H OH rotate C-5 OH to rear HO HO HO H H H OH OH H OH HO HO HO H H OH H OH

H OH H OH HO HO HO H H alpha O 4H-Pyran H OH OH HO HO HO H H hemiacetal OH H beta D-glucopyranoses OH

H H H HOHO O HO H H OH OH H HOHO O HO H H H OH H alpha furanose form beta furanose form D-glucofuranoses O furan OH

H OH H OH HO HO HO H H H OH OH HO HO HO alpha H H OH H OH beta anomers - epimers at C-1 chair conformations - alpha has one group axial beta has all groups equatorial mutarotation in solution to 63.6% beta/36.4% alpha

CH2OHO H H OH CH2OH OH H OH alpha-D-fructofuranose CH2OH O HO H H OH H OH CH2OH D-fructose CH2OHO H H OH OH OH H CH2OH beta-D-fructofuranose

H OH HO HO HO H H OH H CH3OH OH HCl acetal H OH HO HO HO H H OH H OCH3 methyl beta-D-glucoside (glucoside - glucose acetal) non-reducing, does not mutarotate

Disaccharides: ( )-maltose “malt sugar” two glucose units (alpha) ( )-cellobiose two glucose units (beta) ( )-lactose “milk sugar” galactose & glucose ( )-sucrose “table sugar” glucose & fructose

H OH HO HO HO H H OH H H OH HO O HO HO HO HO H H H H ( )-maltose H OH two glucose units alpha C-1 to C-4 OH H OH reducing sugar H OH O OH HO H HO H H ( )-cellobiose OH H OH two glucose units beta C-1 to C-4 reducing sugar

HO OH H OH HO H HO H H O OH HO H galactose beta C-1 to C-4 glucose HO H H ( )-lactose OH H OH reducing sugar HO HO HO H H OH acetal non-reducing H CH2OH H OH OH O H OH CH2OH HO H ( )-sucrose glucose alpha C-1 to beta C1 fructose

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

Amylopectin H2O ( )-maltose ( )-maltose H2O ( )-glucose Also a polyglucose, but branched every 20-25 units: O O O O O O O O O O O O O O O O O O O CH2 O O O O O O O O O

Cellulose is a polyglucose with a beta-linkage: O O O O O O O O O O O O O O O O