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CHE 242 Unit VII The Physical and Chemical Properties, and Reactions of Ketones, Aldehydes, and Amines CHAPTER TWENTY-TH

CHE 242 Unit VII The Physical and Chemical Properties, and Reactions of Ketones, Aldehydes, and Amines CHAPTER TWENTY-THREE. Terrence P. Sherlock Burlington County College 2004. Carbohydrates. Synthesized by plants using sunlight to convert CO 2 and H 2 O to glucose and O 2 .

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CHE 242 Unit VII The Physical and Chemical Properties, and Reactions of Ketones, Aldehydes, and Amines CHAPTER TWENTY-TH

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  1. CHE 242Unit VIIThe Physical and Chemical Properties, and Reactions of Ketones, Aldehydes, and AminesCHAPTER TWENTY-THREE Terrence P. Sherlock Burlington County College 2004

  2. Carbohydrates • Synthesized by plants using sunlight to convert CO2 and H2O to glucose and O2. • Polymers include starch and cellulose. • Starch is storage unit for solar energy. • Most sugars have formula Cn(H2O)n, “hydrate of carbon.” => Chapter 23

  3. Classification of Carbohydrates • Monosaccharides or simple sugars • polyhydroxyaldehydes or aldoses • polyhydroxyketones or ketoses • Disaccharides can be hydrolyzed to two monosaccharides. • Polysaccharides hydrolyze to many monosaccharide units. E.g., starch and cellulose have > 1000 glucose units. => Chapter 23

  4. glucose, a D-aldohexose fructose, a D-ketohexose => Monosaccharides • Classified by: • aldose or ketose • number of carbons in chain • configuration of chiral carbon farthest from the carbonyl group Chapter 23

  5. => D and L Sugars • D sugars can be degraded to the dextrorotatory (+) form of glyceraldehyde. • L sugars can be degraded to the levorotatory (-) form of glyceraldehyde. Chapter 23

  6. The D Aldose Family => Chapter 23

  7. => Erythro and Threo • Terms used for diastereomers with two adjacent chiral C’s, without symmetric ends. • For symmetric molecules, use meso or d,l. Chapter 23

  8. => Epimers Sugars that differ only in their stereochemistry at a single carbon. Chapter 23

  9. => D-glucopyranose Cyclic Structure for Glucose Glucose cyclic hemiacetal formed by reaction of -CHO with -OH on C5. Chapter 23

  10. Reduction of Simple Sugars • C=O of aldoses or ketoses can be reduced to C-OH by NaBH4 or H2/Ni. • Name the sugar alcohol by adding -itol to the root name of the sugar. • Reduction of D-glucose produces D-glucitol, commonly called D-sorbitol. • Reduction of D-fructose produces a mixture of D-glucitol and D-mannitol. => Chapter 23

  11. Oxidation by Bromine Bromine water oxidizes aldehyde, but not ketone or alcohol; forms aldonic acid. => Chapter 23

  12. => Oxidation by Nitric Acid Nitric acid oxidizes the aldehyde and the terminal alcohol; forms aldaric acid. Chapter 23

  13. => Oxidation by Tollens Reagent • Tollens reagent reacts with aldehyde, but the base promotes enediol rearrangements, so ketoses react too. • Sugars that give a silver mirror with Tollens are called reducing sugars. Chapter 23

  14. Disaccharides • Three naturally occurring glycosidic linkages: • 1-4’ link: The anomeric carbon is bonded to oxygen on C4 of second sugar. • 1-6’ link: The anomeric carbon is bonded to oxygen on C6 of second sugar. • 1-1’ link: The anomeric carbons of the two sugars are bonded through an oxygen. => Chapter 23

  15. => Lactose • Galactose + glucose linked 1-4’. • “Milk sugar.” Chapter 23

  16. => Sucrose • Glucose + fructose, linked 1-1’ • Nonreducing sugar Chapter 23

  17. => Cellulose • Polymer of D-glucose, found in plants. • Mammals lack the -glycosidase enzyme. Chapter 23

  18. => Amylose • Soluble starch, polymer of D-glucose. • Starch-iodide complex, deep blue. Chapter 23

  19. => Nucleic Acids • Polymer of ribofuranoside rings linked by phosphate ester groups. • Each ribose is bonded to a base. • Ribonucleic acid (RNA) • Deoxyribonucleic acid (DNA) Chapter 23

  20. => Ribonucleosides A -D-ribofuranoside bonded to a heterocyclic base at the anomeric carbon. Chapter 23

  21. Ribonucleotides Add phosphate at 5’ carbon. Chapter 23

  22. Structure of RNA => Chapter 23

  23. Structure of DNA • -D-2-deoxyribofuranose is the sugar. • Heterocyclic bases are cytosine, thymine (instead of uracil), adenine, and guanine. • Linked by phosphate ester groups to form the primary structure. => Chapter 23

  24. Base Pairings => Chapter 23

  25. => Double Helix of DNA • Two complementary polynucleotide chains are coiled into a helix. • Described by Watson and Crick, 1953. Chapter 23

  26. DNA Replication => Chapter 23

  27. POWER POINT IMAGES FROM “ORGANIC CHEMISTRY, 5TH EDITION”L.G. WADEALL MATERIALS USED WITH PERMISSION OF AUTHORPRESENTATION ADAPTED FOR BURLINGTON COUNTY COLLEGEORGANIC CHEMISTRY COURSEBY:ANNALICIA POEHLER STEFANIE LAYMAN CALY MARTIN Chapter 23

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