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Chemistry 14D Winter 2010 Final Exam Part A Page 1 OK to “Ph” anywhere where appropriate on part A and part B of this exam. The formation and hydrolysis of amides is of fundamental importance to the biological synthesis and degradation of proteins. The kinetics and mechanism of amide hydrolysis have been studied extensively. For example, hydrolysis of molecule A in pure water is very slow. O H2O Hydrolysis very slow N CH3 CH3 Molecule A In questions 1–11 we explore some aspects of amide chemistry and related topics. 1. (2) In the boxes write the two major product of the hydrolysis of molecule A in the presence of aqueous NaOH. O NaOH H2 O N CH3 and CH3 2. (3) Complete this statement by adding no more than ten words: Hydrolysis of molecule A with aqueous NaOH is faster than hydrolysis with water by itself because... 3. (6) Write the mechanism for the reaction of question 1. 4. (2) In the boxes write the two major products of the hydrolysis of molecule A in the presence of aqueous H2SO4. O H2SO4 H2 O N CH3 and CH3 Page 1 score = Chemistry 14D Winter 2010 Final Exam Part A Page 2 5. (3) Complete this statement in twenty words or less: Hydrolysis of molecule A with aqueous H2SO4 is faster than hydrolysis with water by itself because... 6. (10) Write the mechanism for the reaction of question 4. 7. (6) Enzymes may also be used for amide hydrolysis. Describe two different ways in which an enzyme causes amide hydrolysis to be faster than hydrolysis with water by itself. Be very specific. Reason #1 (twenty words or less): Reason #2 (twenty words or less): 8. (2) Chymotrypsin is a serine protease that uses the side chain of serine to perform the amide hydrolysis. The side chain of serine is CH2OH. Consider the rate of the same amide hydrolysis using a cysteine protease. (The side chain of cysteine in CH2SH.) Based on the information given what can we conclude about the rate of these two reactions (circle one)? (a) Rate of reaction with serine protease > rate of reaction with cysteine protease (b) Rate of reaction with serine protease < rate of reaction with cysteine protease (c) Cannot determine Page 2 score = Chemistry 14D 9. Winter 2010 Final Exam Part A Page 3 (4) Compared to the same reaction of molecule A, the rate of hydrolysis with NaOH for molecule B is (circle one): Faster O Slower Complete this explanation by adding no more than twenty words: This is because... N NO2 CH3 Molecule B 10. (4) Compared to the same reaction of molecule A, the rate of hydrolysis with NaOH for molecule C is (circle one): Faster O Slower O CH3 Complete this explanation by adding no more than twenty words: This is because... 11. (4) Compared to the same reaction of molecule A, the rate of hydrolysis with NaOH for molecule D is (circle one): Faster CH3 Molecule C NO2 O Slower Complete this explanation by adding no more than twenty words: This is because... CH3 Molecule D Page 3 score = Chemistry 14D Winter 2010 Final Exam Part A Page 4 12. (10) Write the mechanism for this transesterification reaction. O O H2SO4 CH3CH2OH OCH3 OCH2CH3 13. (11) Write the mechanism for this imine hydrolysis reaction. CH3 N O HCl + CH3NH3 H2O H Page 4 score = Chemistry 14D Winter 2010 Final Exam Part A Page 5 14. (2) What reactants must be mixed to make H2C=CHMgBr? Complete the following a reaction, but do not include the mechanism. H2C CHMgBr Questions 15–17 refer to the equilibrium between ascorbic acid (molecule E) and its isomer (molecule F). OH OH O O O O OH OH HO OH Molecule E HO O Molecule F 15. (1) For the equilibrium between molecule E and molecule F (circle one): Keq < 1 Keq > 1 16. (6) Complete these two specific and distinctly different reasons for your choice in the previous question by writing E or F in each blank as needed, and then by adding no more than twenty words in each case. Molecule ____ is more stable than molecule ___ because... Molecule ____ is more stable than molecule ___ because... 17. (4) Write a mechanism for the conversion of molecule E into molecule F via aqueous H2SO4. 18. (2) Draw an enamine that has exactly 7 carbons atoms and exactly 13 hydrogen atoms, plus any number of atoms of other elements as necessary. Your enamine cannot be aromatic. Page 5 score = Chemistry 14D Winter 2010 Final Exam Part A Page 6 19. (6) Write the major organic product(s) in the boxes. Assume reagents above/below the arrows are in excess unless otherwise specified. Do not include any mechanism details. If no reaction occurs write “NR.” O O O NaBH4 (a) (CH3)2N OCH3 O O (b) CH3CH2OH MgBr 1. (CH3)2N OCH3 2. H3O 20. (12) Write a mechanism. CH3 O CO2 1. CH3CH2CO2CH3, CH3O, CH3OH 2. NaOH Page 6 score = Chemistry 14D Winter 2010 Final Exam Part A Page 7 Question 21 is an extra credit questions on pharmaceutical chemistry. The points earned from this question will be added to your total score for part A of this exam, but cannot raise the score above 100. 21. (6) After each term in write one choice from the choices list that is the best match. The choices may be used once, or more than once, or not at all. (a) DNA cutter: (b) DNA intercalator: (c) DNA alkylator: (d) Suicide inhibitor: (e) Enzyme inhibitor: (f) Receptor inhibitor: (g) Prodrug: Choices: Agonist, amphotericin B, antagonist, calicheamicin, ethidium bromide, folic acid, mechlorethamine, prontosil, QSAR, SAR, sulfanilide, none of these. Page 7 score =