Ch 22 answers - Answers to Extra Problems for Ch. 22...

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Answers to Extra Problems for Ch. 22 Nelsen, Chem 345 1. Show the major product (or products if more than one will be formed in significant amount) for the following reactions: H 3 O + , H 2 O (two products) NaBH 4 , H 2 O (Fischer projection, C 6 at bottom) as glucose but inverted note configuration at C 3 (altrose) a. b. The product is meso O OCH 3 OCH 3 H 3 CO H 3 CO OCH 3 O OH OCH 3 H 3 CO H 3 CO OCH 3 O OH OCH 3 H 3 CO H 3 CO OCH 3 O OH OH HO HO OH CH 2 OH OH H H OH H OH H OH CH 2 OH C 6 NaCN, H + (less than one equivalent) O OH CN OH OH c. warm dilute HNO 3 O HO HO OH OH HO 2 C CO 2 H OH OH OH d. O HO OH H OH HO excess (EtO) 2 SO 2 NaOH O EtO OEt OEt EtO O EtO OH OEt EtO H 3 O + H 2 O e. f. O O CO 2 H HO HO 1. LiAlH 4 (excess) 2. Neutralize CH 2 OH CHOH CHOH CHOH CH 2 OH g. (stereochemistry will not be graded) HO OH OH NaIO 4 ,H + (give all organic products) H H O H OH O H O Base catalyzes ring opening of hemiacetals, which isomerizes the starting material forming both anomers of the acetal.
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2 2. Stereochemistry stuff a. Which of these are D-aldotetroses that gives a meso diacid? only d . ( b and d are D-aldotetroses; c and d give meso diacids) b. How many asymmetric centers are present in Maltose? 10. There is no symmetry (note that one ring is axially substituted and the other is equatorially, and the left ring is a glycoside (acetal) while the right ring is a hemiacetal). Each aldohexose has 5 asymmetric centers. c.How many aldose and ketose, and furanose and pyranose units are present in Maltose? 2 aldose, 0 ketose, 0 furanose, 2 pyranose Both sugars in maltose are glucose, an aldose, in their pyranose form. 2.d. Which picture has an arrow pointing to the glycosidic linkage?
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This note was uploaded on 02/14/2011 for the course ORGANIC CH 341 taught by Professor Idk during the Spring '11 term at University of Wisconsin Colleges Online.

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Ch 22 answers - Answers to Extra Problems for Ch. 22...

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