Problems Set - Meeting #7

Announcement: There will be not labs on Thursday, November 11, 2004. The first lab conducting the Diels-Alder experiment will be on Tuesday, November 16, 2004.

1. The following questions refer to benzyne

a. why is it considered aromatic despite having 8p-electrons?

b. why is it formed in "in-situ" in this reaction?

2. A student dissolves 0.6 g of tetraphenylcyclopentadienone and 0.4 g of anthranilic acid in 10 mL of tetrahydrofuran and then adds 0.5 mL of isopentyl nitrite.

a. How much carbon monoxide (in units of mL) is given off (assume reaction goes to completion) (Hint: CO might be treated as an ideal gas here!)?

b. Which size of flask would be appropriate for the reaction?

3. Why is the function of 1,2-dimethoxyethane in this reaction?

4. The reaction of cyclopentadiene with maleic anhydride affords the endo product is conducted at room temperature. Explain briefly and show appropriate diagrams.

5. A UV-Vis spectrum is also obtained for the compound obtained in this week's experiment.

a. Why does the procedure ask to use a quartz cuvette and not a plastic cuvette like in the last experiment?

b. What do you expect to change in the UV-Vis spectrum in comparison with last week's product?

c. Which concentration is needed for the UV-Vis characterization of the TPN?

6. Why is the development of a new pharmaceutical compound a very expensive process?