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Published byErnest Johnson Modified over 9 years ago
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Carbohydrates (McM chapt 25) Glucose: C 6 H 12 O 6 = “C 6 (H 2 O) 6 ” Monosaccharides / Simple carbohydrates: Can not be hydrolyzed to simpler carbohydrates D-shugars
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Open and cyclic forms
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Monosaccharides - Reactions (McM chapt 25.7) Functional groups: Alchohols, aldehydes/ketones, hemiacetals React like ROH
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Glycosides in nature DNA / RNA More hydrophilic metabolite of RXH Metabolism
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Glycyrrhizin Saponin from liquorice (lakris) root expectorants (slimløsende) respir. tract infect. From microorganisms:
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Stereoselectivity in glycoside syntheses
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The anomeric effect Stereoselective synthesis of -glycisides - Koenigs Knorr react
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Reduction of carbonyl: Oxidative reactions: “Reducing shugars”: Easily oxidized (most often aldeh. - acid) Tollens Fehling Benedict [old diabetes (glucose) test] Tests (visual results) Not used in synthesis (preparative scale)
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Ketoses as “reducing shugars” Synthetically useful oxidations
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Chain Lengthening and Shortening
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Monosaccharides / Simple carbohydrates: Can not be hydrolyzed to simpler carbohydrates Disaccharides (McM chapt 25.9) Complex carbohydrates: Disacch., polysacch. Can be hydrol. to monosacch. (cleav. of acetal / hemiacetal)
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Milk intolerance
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Polysaccharides (McM chapt 25.10) Cellulose Long chains (>1000 monosachh.) H-bond between chains Structural material - plants -glycoside link., not digested humans Starch: Amylose and amylopectin Amylose ca 20% Amylopectin ca 80% Energy storage plants -glycoside link., digested humans Glycogen ≈ amylopectin, larger, more branches Energy storage animals
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Synthesis Di- and Polysaccharides Building from monosaccharides - Challenges Regioselectivity Stereoselectivity Stability
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Other carbohydrates (McM chapt 25.11-12)
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Aminoglycoside antibiotics Lincomycin antibiotics Glycoproteins / Glycopeptides
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Neuraminidase Inhibitors Effect on influenza virus A and B(?) Inhib. neuraminidase (enzyme that breaks bonds between HA* in newly HA in formed virus and host cell) Prevents release of virus HA: Hemaglutinin, (glycoprotein) important for bonding between influenza virus and host
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≈ S N 1 ≈ TS ‡ Zanamivir Relenza® Oseltamivir Tamiflu®
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