Chemistry of Carbohydrates PDF

# Chemistry of Carbohydrates ## Carbohydrates * Polyhydroxy ketonic or aldehydic compounds * Cn(H2O)n Hydrated Carbon ## Simple Sugars (Monosaccharides) * Can't be hydrolysed to simpler units * CnH2nOn ### Aldose * C2 Aldotriose * C4 Aldotetrose * C5 Aldopentose * C6 Aldohexose * C7 Aldoheptiose ### Ketose * Ketotriose * Ketotetrase * Ketopentose * Ketrohexose * Ketoheptose ## Complex Sugars ### Disaccharides * Can be hydrolysed into 2 sugar units * E.g: * Maltose Glucose + Glucose * Lactose Glucose + Galactose * Sucrose Glucose + Fructose ### Polysaccharides * Can be hydrolysed into many sugar units * E.g: * Starch * Glycogen * Cellulose * Chitin * Inulin * Biopolymer of numerous fructose units ## Examples of Monosaccharides (by Fischer Projection) ### Triose (C3H6O3) | Aldotriose | Ketiotiriose| |---|---| | CHO CHOH H D-glycerase (Glyceraldhyde)| C=O CHOH CHOH Dihydroxy A cetone (DHA) | ### Tetrose (C4H8O4) | Aldotetrose | Ketatetrose| |---|---| | CHO HOCH CHO CHOH D. Erythrose D. Therease | CHO C=O CHOH CHOH D. Erythrulose (Threoulase)| ### Pentose (C5H10O5) | Aldopentose | Kehopentose| |---|---| | CHO HOCH OH CHOH CHOH D-Ribose D-Xylose| CHO C=O CHOH CHOH CHOH D. Ribulase D-Xylulose | ### Hexase (C6H12O6) | Aldohexose | ketohexose| |---|---| | CHO HOCH HOCH CHO CHOH CHOH D-Glucose D-Mannose D-galactose | CHO C=O CHOH CHOH CHOH CHOH D-fructose | ## Isomerism in Monosaccharides ### Functional Isomers * Having the same Mol. Formula, * C₁→ Aldase * Cz kehose * Differs in functional gp. * E.g: * Glycerose & DHA * Ribose & Ribulose * Erythrose & Enythrulose * Glucose & Fructose * Mannose & Fructose * Galactose & Fructose ### Optical Isomers (Stereo-Isomers) #### D.,L-Isomers (Enantiomers) * Non-Super imposable mirror image * Must ive bor more chinal Center. * DHA without Enantiomers due to Absence of Chiral Centers.. * Glycerose (Glyceraldhyde) has 2 enantiomers; * CHO H CHOH D-glyceraldhyde #### Notes: * In Fischer Mast Oxidised C of Monosaccharides is drawn closest to the top where Numbering is started.. * C₁ Aldose * C2 Kekose * For Numerous Chirals D. & L. Configuration isomers is according to the distal Chiral.. * CHO HOCH OH CHOH CHOH D-Mannose * CHO H OH CHOH CHOH CHOH D-glucase * CHO CHOH HOCH OH CHOH D-Ribulase * CHO OH CHOH HOTD CHOH CHOH D-Ribulase * (+)→Rotates Monochromic polarized light to the Right (Dextrorotatory) * (-)→Rotates Monochromic polarized light to the left (Leovorotatory)... * (*) No Rotation ; Optical inactive (Racemate ; Racemic Mix.) * No. of Optical Isomer = 2n→no. of Chirals.. * Glucose has 4 C* * Fructose is 3 * Glyceroldhyde has 1 C* * DHA has no C* (Chirals) ### Epimers * Chain form of Sugers differ only in Stereochemistry at Single S... * CHO HOCH OH CHOH CHOH D(+)-Mannose * CHO HOCH OH CHOH CHOH D(+). glucose * CHO HOCH OH CHOH CHOH D(+)-Galactose * While Mannose & Galactose aren't epimers.. * D.Erythrose se D. Thereose ⇒ Cz Epimers * CHO CHO CHOH CHOH Erythrase Threase ### Anomers (Diastereomers; have diff. properties) (Hawarth Projection) * & Cycles (Hawarth) of the sugar, have the same Mol. Formula * Buth differ in the Sterechemistry at Anomer C. (Cy of Aldose & Ca of Ketose).. they 're diastereomers of diff. prop. * Melting Point = 146° * Rotation angle = + 112.2 * (Specific Rotation).. * Alpha-anomer * Melting Point = 150°C * Rotation angle = +18.7° * Beta-anomer ## Cyclic formation of Monosaccharides ### Monosaccharides #### In Solid State * Acyclic Hemiacetal of Aldose or ketose * Crystalline form * Open chain form #### In Solution * Exist in Equilibrium Mix. of Cyclic hemiracetal && open form * Equilibrium favors Cyclic hemi-acetal (for Most Sugars).. * R-H + R'OH H-FOR * Aldhyde (Reducing) * Hemi-acetal (Reducing) ### If the Cycle * 6.membered ring (Pyrane) Pyranose * 5-membered ring (furane) furanare ## Cyclic hemiacetal form of Glucose * CHO HOCH OH CHOH CHOH * f of Aldose (Achiral Carbonyl).. * Open Chain * Acyclic Hemi-acetal * d. Anomer * B-anomer * Hawarth Projection of Glucopyranose... ## Cyclic hemiacetal form of fructose * CHO C=O CHOH CHOH CHOH * Open Chain * Acyclic heni-acetal * Haworth Projection of Fructofuranose ## Convert Fischer ⇒ Hawarth * CHO HOCH OH CHOH CHOH * CHO HOCH OH CHOH CHOH * CHO HOCH OH CHOH CHOH * CHO HOCH OH CHOH CHOH ## Convert Hawarth ⇒ Fischer * CHO HOCH OH CHOH CHOH D-Ribulase * CHO HOCH OH CHOH CHOH D-Xylulose * CHO HOCH OH CHOH CHOH D-Mannose ## Muta Rotation * Change in Optical Rotation when Reducing Sugar is dissolved in HO * (due to Existing in Equilibrium between Open Chain form & the banomers ( α & β ) of the Cyclic hemiacetals.. * CHO OH CHOH HOCH CHOH D(+) Glucose * of DC+/glucopyranose (36%) R.A. + 112.2 * (Open Chain) * BCD-)+ glucopyranose (64%) R.A. = + 18.7 ## Evidence of Cyclic Hemiacetal Structure of DC) glucose * Diff. in Melting points * Diff. in Specific Rotation Angles * Solution (Cyclic); No U.V. or I.R alasorbance of 'c=o * Solution (Cyclic); No the Result of Schiff is Reagent (that gives pink Colour with free 'C=0).. ## Synthesis of Monosaccharides ### Descending Sugar series (Chain Shortening) Ruff degradation * CHO HOCH OH CHOH CHOH D-glucase * CHO HOCH OH CHOH CHOH D-Arabinose * CHO HOCH OH CHOH CHOH D-Erythrase ### Ascending Sugar Series (Chain Elongation) Killani. Fisher Syathesis * CHO HOCH OH CHOH CHOH D.arabinose * CHO HOCH OH CHOH CHOH D.Glyceraldhyde * CHO HOCH OH CHOH CHOH D-glucose ## Reactions of Monosaccharides ### Reduction * CHO HOCH OH CHOH CHOH D-Glucose * CHO HOCH OH CHOH CHOH D-Mannase * CEO HOCH OH CHOH CHOH D-Fructose ### Oxidation * CHO HOCH OH CHOH CHOH * CHO HOCH OH CHOH CHOH ### Osazone formation * Condensation of 3 mol. of phenyl hydrazine with 1 mol. of Aldose or kehose to form Yellow pph by Converting Both Cy8&Co, intro Phenyl Hydrazones. * Both Aldase & ketose of the some no. of & give the same resulth (as Only both q & C₂ are conver. hed to Phenylhydrazone * C2 epimers gives the same Osazone mix. (as C2 stereochemistry is lost during the Reaction).. * The formed Osazone mix. is less Sol. in tho than parents sugar, with High Melting points & with definite Crystalline structures.. (ine; Useful in Sugars Charecterization).. * CHO CHOH (CHOH) CHOH Aldose * CHO (CHOH) CHOH Ketose ## Disaccharides * 2 sugars linked together via α or β- (1,2) or (1,4) Glycosidic linkage... * Glycoscidic bond to the Anomeric C may be α or β ### (1) Maltose (Beer or Matt Sugar) * Reducing with Reducing Prop. (with Hemiacetal gr.) (free anomer) * 1,4-a-glycoside 4-0-(α-D-gluco. Pyranosyl)- dork glucopyranose * 4-1,4-glycoscidic linkage.. ### (2) Lactose (Humran Milk (6.5%), Cow milk (4.5%) (Milk Sugar)) * Reducing With Reducing Prop. (with Hemiacetal gr.) (free anomer) * 1,4- B-glycoside 4-0- (B-D-galacto- Pyranosyl). Aor B glucopyranose. * R-1,4-glycoscidic linkage. ### (3) Succrose (Table Sugar) Sugar cane (20%) Sugar beet (15%) * *Honey bee; secrets Invertase Hydrolysing Succrose * Thus Honey Mix. of Succrose, Glucose & Fructose * 1,2-glycoside, 2-0 (α-D-gluco. Pyranasyl). B. D.fructofurano. side * (Non-Reducing Sugar & Anomers are bonded No. Hemiacetals). ## Polysaccharides * 108,100s, or 1000s of simple sugars linked via Glycascidic linkages without free Anomeric hydroxyl except one of the end of the Chain * Thus Non-Reducing sugar * 1,4.0-(β-D glucopyranosyl) polymer * Con Held together via Hydrogen-bonds providing Impact Strength & Rigidity in plant woods, leaves, grasses, & cottons.. * Serve as Raw material of Cellulose acetate (Rayon) ### (1) Cellulase ### (2) Starch (Partially H2O soluble) #### Amylose (20%) * Sol in Ho * loos of glucase linked via a-1,4 glycascidic bonds * Linear.. #### Amylopectin (80%) * Insol. in 20 * 100s of glucose linked via 2-1,4& x-1,6-glycoscides.. * linear with bronches every ≈ 25 glucose units. #### Plant energy storage Starch (for later needs) * eng; Corn, Potatoes, Cereal grains * Eaten Starch by Human can be digested in Digestive System by Glycosidase enzyme which is of High Selectivity & Hydrolyze only @ glycos. cides intro free glucose units.. can't hydrolyze glycoscides in Cellulose thus We con digest Starch in Potatoes, Corn,... & Can'th digest Cellulose in grasses & Plant fibers..

Chemistry of Carbohydrates PDF

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