Carbohydrate Chemistry Part 1 Simple Carbohydrates Dr Kevin

Carbohydrate Chemistry Part 1: Simple Carbohydrates Dr. Kevin Ahern

Outline Simple Carbohydrates • • Nomenclature Structures Cyclizations Modifications

Saccharides Monosaccharides • • • Cx(H 2 O)x Glucose (C 6 H 12 O 6) Fructose (C 6 H 12 O 6) Ribose (C 5 H 10 O 5) Galactose (C 6 H 12 O 6) Glyceraldehyde (C 3 H 6 O 3) X= • • • Tri- = 3 Tetr- = 4 Pent- = 5 Hex- =6 Hept- = 7 Oct- = 8 Aldehydes = Aldoses Ketones = Ketoses

Different Sizes The -oses 3 Carbons 4 Carbons 5 Carbons 6 Carbons D-Glyceraldehyde Triose D-Threose Tetrose D-Ribose Pentose D-Glucose Hexose

Common Sugars Aldose and Ketose Aldehyde } { D-Glucose D-Fructose Aldose Ketone

Simple Sugars Aldopentose Aldohexose Ketohexose Aldohexose

Asymmetric Carbons The Glyceraldehydes L- Configuration Asymmetric Penultimate Carbon D- Configuration Mirror Images L-Glyceraldehyde D-Glyceraldehyde

Multiple Asymmetric Centers • Glucose D-configuration Asymmetric Carbons D-Glucose

Enantiomers • Mirror Images D-configuration L-configuration D-Glucose L-Glucose

Diastereomers • Same chemical type & size, non-mirror images Same Configuration Different Configurations Same Configuration D-Glucose D-Gulose

Epimers • Diastereomers differing in configuration of one carbon only D-Glucose D-Galactose

Cyclization of Sugars New Asymmetric Center In Close Spatial Proximity The New Asymmetric Carbon Is Called Anomeric

Cyclization of Sugars

Cyclization of Sugars

Haworth Structures • Glucose Anomers α-D-Glucopyranose β-D-Glucopyranose

Common Furanoses • Fructose and Ribose β-D-Fructofuranose β-D-Ribofuranose

Conformational Isomers • Chair and Boat Forms of β-D-Glucose

Cyclic Structures • Glucose

Modified Sugars Galactosamine N-acetylglucosamine Fructose-1, 6 -bisphosphate Mannose-6 -phosphate Glucuronic Acid

Glycosides

Sugar Alcohol Sorbitol (Glucitol)

Artificial Sweeteners Sucralose

Disaccharides • Sucrose (glucose + fructose) • Lactose (glucose + galactose) • Maltose (glucose + glucose)

Polysaccharides • • • Cellulose Glycogen Amylose Amylopectin Chitin

Hark the Sucrose (to the tune of "Hark the Herald") Copyright © Kevin Ahern Metabolic Melody Carbohydrates all should sing Glory to the Haworth ring Anomeric carbons hide When they're in a glycoside Glucopyranose is there In the boat or in the chair Alpha, beta, D and L Di-astere-omer hell