Chapter 19 & 20 Esters, Amides and Carbohydrates Chemistry B11 Esters [...]...Amides In an amide, the -OH group in the carboxyl group of a carboxylic acid is replaced by an Amino group (-NH2) CH3 — C—OH O = = O CH3 — C — NH2 Formation of Amides = O RC O H A carboxylic acid A carboxylic acid An Amine O CH 3 C-OH + H HN CH 2CH 3 Acetic acid Ethanamine Heat O RCNHR' + H2O = = O RC -OH H -NHR' An amide O CH 3 C-NHCH 2 CH 3 + H 2 O N-ethylethanamide Naming of Amides Change the... (an enzyme) and they can digest starch products such as pasta (contain α-glucose) Humans do not have β-amylase (an enzyme) and they cannot digest cellulose such as wood or paper (contain β-glucose) Mutarotation Change in specific rotation that accompanies the equilibration of α and β anomers in aqueous solution β-D-glucose 64% Open-chain form < 0.02% α-D-glucose 36% Physical properties of Monosaccharides... end of the name of the carboxylic acids from “-oic acid” to “-amide” methanoic acid = O H–C–NH2 methanamide (IUPAC) = O propanoic acid CH3–CH2–C–NH2 propanamide (IUPAC) Naming of Amides = O CH3–C–NH–CH3 N-methylethanamide = O CH3–CH2–C–N(CH3)2 N,N-dimethylpropanamide = O CH3–C–N(CH2CH3)2 N,N-diethylethanamide Properties of Amides Such as esters: Hydrolysis in hot aqueous acid or base Carbohydrates... important Monosaccharides Galactose (C6H12O6, aldohexose), • • H O C H C OH Has a similar structure to glucose except for the –OH on Carbon 4 HO C H Cannot find in the free form in nature HO C H H C OH • Exist in the cellular membranes of the brain and nervous system • Combines with glucose in lactose (a disaccharide and a sugar in milk) CH2OH Disease - Galactosemia Galactosemia missing the enzyme that... Monosaccharide + H2O 2 Disaccharide + H2O H+ or enzyme H+ or enzyme no hydrolysis two monosaccharide units + 3 Polysaccharide + many H2O H+ or enzyme many monosaccharide units Monosaccharides A carbohydrate that cannot be split or hydrolyzed into smaller carbohydrates Monosaccharides are carbohydrates with: • 3-9 carbon atoms • A carbonyl group (aldehyde or ketone) • Several hydroxyl groups O ║ C─H... Cn(H2O)n CnH2nOn Monosaccharides - Aldose Aldose is monosaccharide: • With an aldehyde group and many hydroxyl (-OH) groups • • • • triose (3C atoms) tetrose (4C atoms) pentose (5 C atoms) hexose (6 C atoms) “Aldo-” + suffix O ║ C ─ H aldose │ H─ C ─ OH │ H─ C ─ OH │ CH2OH an aldotetrose (Erythose) Monosaccharides - Ketose Ketose is monosaccharide: • With a ketone group and many hydroxyl (-OH) groups... photosynthesis in plants • The major source of energy from our diet • Composed of the elements C, H, and O Cn(H2O)n 6CO2 + 6H2O + energy Photosynthesis Respiration C6H12O6 + 6O2 glucose Carbohydrates - The most abundant organic compounds in the plant world - 3/4 of the weight of plants - 1% of the weight of animals and humans (they do not store) - 65% of the foods in our diet Carbohydrates 1 Monosaccharide +... (3C atoms) tetrose (4C atoms) pentose (5 C atoms) hexose (6 C atoms) CH2OH │ C=O ketose │ H─ C ─ OH │ H─ C ─ OH │ H─ C ─ OH │ CH2OH “Keto-” + suffix a ketohexose (Fructose) Some important Monosaccharides Glucose (C6H12O6, aldohexose) – blood sugar • • • Is found in fruits, vegetables, corn syrup, and honey Is found in disaccharides such as sucrose, lactose, and maltose Makes up polysaccharides such as... missing the enzyme that convert galactose to glucose Accumulation of galactose in the blood and tissues Mental retardation and cataract Solution: removing the galactose from food: no milk Fischer Projections - Horizontal lines represent bonds projecting forward from the stereocenter - Vertical lines represent bonds projecting to the rear - Only the stereocenter is in the plane CH O H C OH CH 2 O H Convert... Colorless - Crystalline solids - Soluble in water (H-bond because of OH groups) - Insoluble in nonpolar solvents Oxidation of Monosaccharides H O C H O OH C H C OH H C OH HO C H HO C H H C OH + 2Cu H C OH CH2OH D - glucose Aldonic acids 2+ Benedict’s Reagent (blue) Oxidation H C OH + Cu2O(s) H C OH (Brike red) CH2OH D – gluconic acid Reducing sugars: reduce another substance Oxidation of Monosaccharides CH2OH . Esters Hydrolysis: reaction with water. (breaking a bond and adding the elements of water) RCO R ' O RC-OH O H - O R ' = = An alcohol A carboxylic acid An ester +. Amides = O = O Formation of Amides RC O H O A carboxylic acid = RCNHR ' O RC-OH O H - N HR = = An Amine A carboxylic acid An amide Heat + H 2 O ' H 2 OCH 3 C-NHCH 2 CH 3 O H