BMS100 Monosaccharides Pre-learning Part 1 PDF

Monosaccharides Carbohydrate Prelearning Material Part 1 Dr. I. Fraser (Recording: Dr. Heisel) BMS100 Objectives – Prelearning 1 Define the different types of isomers and be able to classify pairs of monosaccharides according to their isomeric relationships With respect to monosaccharides, use D, L...

Monosaccharides Carbohydrate Prelearning Material Part 1 Dr. I. Fraser (Recording: Dr. Heisel) BMS100 Objectives – Prelearning 1 Define the different types of isomers and be able to classify pairs of monosaccharides according to their isomeric relationships With respect to monosaccharides, use D, L designations correctly Terminology Review O H C1 H C2 OH C H HO 3 H Aldehyde H C1 O C HO C OH 2 3 H H C4 OH H C4 OH H C5 OH H C5 OH H C OH H C6 OH 6 H D – Glucose (an “aldose”) Ketone H D – Fructose (a “ketose”) Isomers Same chemical formula, different structure R3 Stereoisomers: same atoms in same order, but different spatial arrangement (must have a chiral carbon) Enantiomers: mirror images - Given D or L designations based on position of OH group attached to the chiral C atom furthest from aldehyde or ketone group: D = right, L = left (D form predominates in nature) R1 - C - R2 R4 H C1 O H C 2 OH HO C3 H H C 4 OH H C 5 OH H C6 OH H Structural isomers: same atoms, but not in the same order Diastereomers: not mirror images - May or may not be epimers: epimers differ at only at 1 chiral carbon Structural Isomers Both glucose and fructose (C6H12O6) are structural isomers H O H C1 H C2 OH C H HO 3 Aldehyde H C1 O C HO C OH 2 3 H H C4 OH H C4 OH H C5 OH H C5 OH H C OH H C6 OH 6 H D - Glucose H D - Fructose Ketone Structural Isomers The conversion between glucose and fructose happens via an isomerization reaction Intramolecular shifting of bonds Isomerization reactions can also create stereoisomers Take a look at the isomerization reaction on the next slide Which sugars are structural isomers vs stereoisomers? Review: Which are ketoses vs aldoses? Structural Isomers and Stereoisomers H H H C1 H C2 HO H H H C 3 H C2 OH H C4 OH C5 OH C6 H D Glucose OH C 1 OH HO OH C3 H C OH O C HO O C1 2 3 H H C4 OH D Fructose H C5 OH H C6 OH H H C4 OH H C5 OH H H C6 OH HO C2 H HO C H Enediol Intermediate C1 3 O H H C4 OH H C5 OH H C6 OH H D Mannose Stereoisomers: Enantiomers Stereoisomers can be diastereosomers or enantiomers. - Enantiomers are mirror images O H C1 H C2 OH C H HO 3 O H C1 HO C2 H C OH H 3 H C4 OH HO C4 H H C5 OH HO C5 H H C OH H C OH 6 H D - Glucose 6 H Mirror L- Glucose Question O H C1 H C2 OH C H HO 3 H C4 OH HO C5 H C OH H 6 H Is Idose a D or L sugar and why? Stereoisomers: Diastereomers Any stereoisomer that is not an enantiomer is a diastereomer. - A diastereomer may or may not be an epimer H C1 O O H C1 C2 OH C H HO C2 H H HO C3 H HO 3 O H C1 H C2 OH HO C H 3 H C4 OH H C4 OH HO C4 H H C5 OH H C5 OH H C5 OH H C OH H C OH H C OH 6 6 H H D - Mannose D - Glucose 6 H D - Galactose Terminology review Which of these stereoisomers are enantiomers, and which are diasterosomers? Are there any epimers? O H C1 H C2 OH C H HO 3 H C1 H C2 HO O OH C3 H O H C1 HO C2 H C OH H 3 H C4 OH H C4 OH HO C4 H H C5 OH HO C5 H HO C5 H H C6 OH H C6 OH H C6 OH H D - Glucose H L - Idose H L- Glucose Isomers – Self Test What is the difference between stereoisomer and structural isomer? What is the difference between an enantiomer and a diastereosomer? When is a diastereosomer an epimer? Optional Resources End of prelearning If you would like an more in-depth explanation of some of this material, you can use the links to the videos that are found at the end of the powerpoint version of this recording Note that these videos may include extra details for the purposes of providing a detailed explanation. In terms of assessment, only the level of detail presented on the slides that were covered in the pre/post learning and in class will be tested.