Chemistry 190: Organic Chemistry Questions And Answers

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Name__________________________

Chemistry 190: Organic Chemistry

EXAM 3
Thursday April 21, 2011

1. (12) ______ 2. (14) ______ 3. (20) ______ 4. (12) ______ 5. (54) ______ 6. (16) ______ 7. (12) ______ 8. (10) ______ Total (150) ______

The exam consists of twelve numbered pages and an unnumbered cover sheet. Make certain that you have a complete exam. You will have two hours to work on the exam. No books or notes are allowed; however, you may use a molecular model set and a calculator. For full credit, please show all of your work. Read all of the questions carefully. You are advised not to spend an inordinate amount of time on any one question until you have attempted all of the others. If you get stuck on a problem, write down
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1. (12 points) Butaclamol is an antipsychotic drug that is prescribed for the treatment of schizophrenia. The structure of butaclamol is shown below. Determine the configuration (R or S) for each of the chiral centers in this compound. For full credit (or partial credit if your configuration is incorrect), please show (clearly labeled) how you have prioritized the groups. Also, be certain to clearly indicate which set of priorities/configuration goes with which chiral center.
OH N H H
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(16 points) Using curved arrows to represent the movement of electrons, write a complete mechanism for the following reaction.
OH + OH + HO

H2SO4 H2O

10

7. (12 points) Propose a series of reactions that could be used to convert 2-methylpentane into 3bromo-2-methylpentane, as shown below. You do not need to show mechanisms for your proposed reactions but you should show the intermediate products of each of the individual reactions. Consider the selectivity of the reactions that you propose to use for your synthesis, making certain that you choose reactions that will give your desired products as the major products.

Br

11

8. (10 points) When (R)-4-bromopentanoic acid, 1, is treated with sodium hydroxide, (R)-4hydroxypentanoic acid, 2, is isolated as the only product. Using curved arrows to represent the movement of electrons, write a mechanism for this reaction that explains the formation of the product with particular attention to its observed stereochemistry.
Br OH O 1 2 + HOO OH OH + Br-

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