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Unformatted text preview: W08_215_E3 Blank Copy JOC , 2008 , 73, 1234 OH H OH OCH 2 Ph H O H NO 2 PhS PhS b) Draw a Fischer Projection of the open chain form of Molecule F: PhCH 2 O a) How many stereoisomers would Molecule F have (not including F itself)? Molecule F c) ( JOC , 2008 , 73 , 1379) Label the stereocenters in the following ribo- phytophingosine. ( Circle R or S ) I. ( 25 points) CH 2 OH H NH 2 H OH C 13 H 27 H OH R or S R or S R or S e) How many epimers does D- allose have which are also D- aldohexoses? f) How many epimers does D- allose have which are L- aldohexoses? ( JACS , 2007 , 129 , 9885) Lowary synthesized an oligosaccharide that tuberculosis bacteria include in their cell walls. The oligosaccharide includes 22 D-arabinofuranose residues, four of these are !-arabinofuranosides, !-linked sugars that are hard to introduce in a stereocontrolled manner. The others are linked via " (1 -> 5), " (1 -> 3), and ! (1-> 5) linkages. Arabinose is (2S,3R,4R)-2,3,4,5-tetrahydroxypentanal. g) Draw the Fischer projection of D-arabinose h) Draw the Haworth projection of !-D-arabinofuranose d) A stamp commemorating sugar chemist and Nobel Laureate Gerty Cori featured an incorrect chemical structure. Draw the correct chair structure of "-(D)-glucopyranose-1-phosphate. (The molecule will have a -2 charge.) i) Draw a disaccharide of "# D-arabinofuranose with an " (1 -> 5) linkage 2 3 2 2 4 3 3 3 3 H W08_215_E3 Blank Copy...
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