l33 - Carbohydrates Carbohydrates CO2 + H2O C6H12O6 + O2...

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Unformatted text preview: Carbohydrates Carbohydrates CO2 + H2O C6H12O6 + O2 glucose a carbohydrate (CnH2nOn) Carbohydrates HO OH O H+ Draw 4 possible products CO2 + H2O C6H12O6 + O2 OH HO O H OH HO O OH H O OH H OH O H OH i ii ii iii iii iv HO OH O H+ Which 2 are the most favorable? A B C D E F i + ii ii i + iii i + iv ii + iii ii + iv iii + iv HO OH O H+ Which 1 is the most favorable? A B C D i ii iii iv OH HO O H OH HO O OH H O OH H OH O H OH HO O H OH HO O OH H OH O OH H OH O H OH i ii ii iii iii iv i ii ii iii iii iv HO OH O H+ H OH OH OH O OH O H H HO HO OH H O OH HO H H OH HO HO H H H O O H H H HO beta H glucose (pyranose) (pyranose) glucose (acyclic) OH OH O OH O H OH H alpha Two cyclic forms of glucose are known. What is the stereoisomeric relationship between these two cyclic structures? Are their simpler ways to draw glucose with all of its stereochemical information preserved? H OH HO HO H H O H HO O H H OH H O OH HO H H OH HO HO H H H O O H OH HO HO H H O H OH H O OH HO H H OH HO HO H H H O O + H HO HO H + H H H HO H HO HO H H HO O H H H HO H glucose (pyranose) (pyranose) glucose (pyranose) (pyranose) glucose (acyclic) CHO (A) They are identical. (B) They are enantiomers. (C) They are diastereoisomers. (D) They are not stereoisomers. H HO H H OH H OH OH CH2OH Fischer Projections: What do these lines mean? Choose the structure of L-threose from the following LFischer projection. CHO H HO OH H OH OH CH2OH CHO CHO H HO OH H OH OH CH2OH CHO H OH HO HO H H O H HO O H H HO H H OH H OH OH CH2OH CHO H HO OH H CH2OH L-threose = H HO R CHO OH H HO H H OH H OH OH CH2OH H = H H S H = H H CH2OH Fischer projection projection HO H H OH CHO H OH CHO Fischer Fischer projection projection HO H CHO S HOH2C R HOH2C R HOH2C HO H S HOH2C HO H CHO S H OH S H OH R R (A) (B) (C) (D) Are Are similar structures used for the cyclic isomers? How many stereoisomers of acyclic glucose are possible? C HO CH2OH H H OH OH H OH O H OH H H HO H H CHO CH2OH H H OH OH H OH O H OH OH H OH H H H OH CH2OH O H H OH H HO H H OH H OH OH CH2OH * * * D * OH H OH OH CH2OH Haworth Haworth projections Fischer projection projection D=R A B C D 2 4 8 10 E F G H 12 16 16 24 32 How many hexoses with the D configuration are possible? What are the structures of all of the D sugars? CHO D-glyceraldehyde CHO H OH H OH OH CH2OH H C OH CH2OH A B C D 2 4 8 10 10 E F G H 12 16 24 32 32 HO H H What are the isomers of D-glucose? DD-glyceraldehyde H CHO C OH OHC HO C H L-glyceraldehyde S-glyceraldehyde (-)-glyceraldehyde H H H HO H H C O OH H OH OH H OH HO HO H HO H O H OH H H H OH HO H HO HO O H OH H R-glyceraldehyde (+)(+)-glyceraldehyde (d )-glyceraldehyde H CH2OH HOH2C CHO C OH OHC HO C CH2OH HOH2C (l )-glyceraldehyde CH2OH D-glucose H H HO H H C O H OH OH H OH OH CH2OH HO HO H HO HH H OH O β-D-glucopyranose H OH HO HO HO H H H OH OH α-D-glucopyranose mirror plane What are the isomers of D-glucose? DH H HO H H C O OH H OH OH CH2OH H OH HO H HO HO H O H OH H H OH HO HO HO H H H OH OH H β-D-glucopyranose H OH HO H HO HO O H OH H What is the stereochemical relationship of the α and β isomers to each other? H H HO H H C O OH H OH OH CH2OH H H OH β-D-glucopyranose HO H HO HO O H OH H 64% D-glucose H H HO H H C O OH H OH OH CH2OH D-glucose H H HO H H C O OH H OH OH CH2OH diastereomers anomers H OH HO HO HO H anomeric carbon 0.003% H H OH OH 36% α-D-glucopyranose α-D-glucopyranose Review: Glucose β-D-glucopyranose H OH HO H HO HO CHO H HO H H OH H OH OH CH2OH H H C O OH H OH OH CH2OH H OH HO H HO HO H H O H OH H Predict the product of the following reaction. H OH a mono methyl ether OH OH H HO CH3OH H HO H HO HO H O H OH H 64% = HO H H = O H OH H H OH HO HO HO H H H OH OH H OH OH O OH O H O H3C H H3C H O OH OH H O OH H O OH H OH H H HO 0.003% H D-glucose A OH O H HO H H3C H B OH OH OH H HO H H O OH H CH3 O C 36% CH3 H O OH H α-D-glucopyranose D E Predict the product of the following reaction. β-D-glucopyranose H OH HO HO HO H H OH H CH3 O H CH3OH CH3OH H H OH HO HO HO H OH HO HO HO H H OH H CH3 O H H OH H H H OH HO H HO HO O H OH H H Why is the hydroxyl group on the anomeric carbon so reactive? β-D-glucopyranose H OH HO H HO HO CH3OH H OH HO HO HO H H HO HO HO H H H OH O CH3 CH3OH H OH HO HO HO H H H OH OH H H O H OH H H OH HO HO HO H H OH H CH3 O H H OH glycosidic bond H OH H α-D-glucopyranose ...
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This note was uploaded on 01/09/2011 for the course CHE 322 taught by Professor Staff during the Spring '08 term at SUNY Stony Brook.

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