ATTN: answers to the below questions are due at the start of your second meeting (10/3 or 10/4); these answers should be part of your pre-lab write-up. The first quiz will be administered in lecture on Monday 10/9/2006. Please make sure that you arrive on time.

Important announcement: The lecture was moved to Humanities 135.

1. Referring to step 2, answer the following questions:

a. In the initial phase, the phenol is dissolved in methanol and sodium hydroxide is added. Provide a balanced equation and explain why it is important to dissolve the sodium hydroxide completely before proceeding.

b. Which compound is used as the electrophile in this reaction? How is it introduced into the reaction?

c. The reaction mixture (usually a brownish oil) is poured in water and the mixture then acidified using conc. HCl. Explain briefly and provide pertinent chemical equations.

d. Dichloromethane is used as solvent for the extraction. Rationalize your choice.

e. The organic layer is extracted with sodium bicarbonate at some point in the work-up procedure. Why?

f. Many students observe a viscous liquid as their crude product. Explain briefly. How should these students proceed?

g. Sketch the TLC plate (SiO₂, CH₂Cl₂/hexane (1:1)) with your product in lane 1, the starting phenol in lane 2 and the salicylaldehyde (product from step 3) in lane 3. What would change if the solvent mixture used would be CH₂Cl₂/hexane (5:1)?

2. Why does asymmetric synthesis play a very important role in the production of many pharmaceuticals?

3. Spectroscopy

a. Sketch a ¹H-NMR spectrum for ibuprofen. What type of multiplets do you expect to observe and why?

b. Identify four pertinent peaks in the IR spectrum of ibuprofen.