<p> Ch 336 - Exam 3 June 6, 2001 Name (please print) </p><p>H CH3CH2 1. (18) Give a name or structure, a) N CH2 CH2 N CH3CH2 as appropriate. H3C CH3 a) (Chemical Abstracts) b) any non-reducing disaccharide (ignore stereochemistry) c) -D-fructopyranose (chair)</p><p>2. (16) D-galactose is the C-4 epimer of D-glucose (Fischer projection). -D-Galactopyranose and -D-glucopyranose (read the names carefully), considered as a related pair where appropriate, </p><p>True False Can’t tell True False Can’t tell are diastereomers | | are aldopentoses | | are both labile | | are structural isomers | | are constitutional isomers | | are epimers | | are conformational isomers | | are enantiomers | | are stereoisomers | | are rotational isomers | | are both dextrorotatory | | are anomers | | are cyclic hemiacetals | | are conformers | | give the same product | | are both reducing | | with dilute nitric acid sugars</p><p>3. (4) Lemon juice is effective in getting rid of the fishy smell of a fish that has been too long out of the water. Using generalized structures (functional groups with R- groups), explain why the odor is reduced, including equations for any reactions that take place.</p><p>O H 4. (10) a) A D-sugar of unknown C dil. stereochemistry, A, is oxidized by CHOH HNO3 A CHOH B dilute nitric acid to an optically H C OH inactive compound, B. Give all CH OH possible structures for B (Fischer 2 projections).</p><p> b) Ruff degradation of A yields a new sugar, C, which is reduced with NaBH4 to an optically active compound, D. Give equations for all reactions, and deduce the structure of A. Explain your reasoning. 5. (8) a) The optical activity of some sugar solutions gradually changes with time until it eventually reaches a constant value. This experimental phenomenon is known as . b) One sugar that exhibits this behavior is D-glucose. With words and three-dimensional structures (chair, etc.), explain the changes taking place in the solution.</p><p>6. (36) Complete the following. Show stereochemistry clearly for those marked with a star.</p><p>CH2OH (excess) (excess) O Ph-NH-NH Ph-NH-NH a) HO 2 2 OH CH3CO2H CH3CO2H</p><p>CH2OH</p><p>1. CH3I (excess) b) CH2 CH2 CH CH3 + N 2. Ag2O/H2O H C H 3 3. (major) (minor)</p><p> excess H O Cellulose 2 c) + H3O</p><p>CH2 OH O + O H3O d) OH + H O CH2OH 2 OH H (salicin, from OH willow bark) OH</p><p>N N SO3H e) +</p><p>HO3S</p><p>OH</p><p>1. K 2CO3/H2O/ + CO f) 2 + 2. H 3O 7. (10) Give a mechanism for the following. Include formal charges, show individual steps clearly, and use correct + electron pushing. (The use of the symbol H is not acceptable.) CH OH OH O 3 CH – OH 3 O + CH3–Br CH2 CH2 C CH3</p><p>8. (10) Suggest a synthesis for the following target molecule from the indicated starting materials as well as any other necessary reagents. Show all intermediate products (no mechanisms). O H I C CH2 N CH2 OCH3 , target H3C H C (trans) (cis) 3</p>