Chemistry 342 M. Walker
Alternate Final Exam (3 hour)
YOUR NAME______________________________
360 points total. You may use molecular models for this exam.
1. (72 points total) Predict the major organic product(s) for each of the following reactions. Include the stereochemistry of the product where appropriate- if racemic just say so.
2. (20 points) Explain (using resonance forms) why the H on nitrogen in succinimide (I) is much more acidic than the corresponding H in pyrrolidine (II).
3. (12 points) Draw structures for any two of the following compounds.
4. (100 points total) The following questions all refer to the reaction schemes shown below. These are taken from a paper on synthesis of anti-HIV drugs in a 1992 issue of the "Journal of Medicinal Chemistry".
(a) (10 points) Scheme I outlines two possible syntheses of a secondary amine. What are the problems associated with method a?
4(contd.). (b) (24 points) Give a complete mechanism (with curved arrows) for the first part of route b in Scheme I (the reaction of the amine with an aryl aldehyde).
(c) (26 points) (a) What is the name of the reaction in stage a of Scheme II, involving a ketone reacting with HCO2Et and NaOMe? Give the full mechanism (with curved arrows) for this reaction. [Hint: Try drawing resonance forms of the product to make it more familiar].
4(contd.). Stage b in Scheme II involves the formation of a heterocyclic ring, as shown in Fig. 1 below. The enol tautomer of the product is shown as the end product.
(d) (12 points) In the box in Figure 1, draw in the curved arrows to show the electron flow in this step of the mechanism.
(e) (10 points) What class of reaction is the step following the boxed step in Fig.1?
(f) (18 points) What type of reaction is occurring in the final step of the mechanism in Figure 1? What is the driving force for this step?
5. (50 points) Synthesize any two of the following using the starting materials shown, and any legitimate reagent of two carbons or less. You may also use formate or acetate esters, dithiane and phthalimide.
6. (45 points) How might you effect the following transformations in a practicable manner? Some conversions may require more than one step.
7. (16 points) For each set of three compounds, circle the most acidic at the hydrogen shown in bold.
8. (20 points) Give a complete mechanism (with curved arrows) for the transesterification reaction shown:
9. (25 points) Fill in the boxes in the following synthesis with structures or reagents as necessary. Include stereochemistry where appropriate, and indicate if racemic or not.
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