Problems Set - Meeting #4
Announcements:
1. Make sure that you make progress on your formal report as well in terms of literature search and writing the parts that you completed already in the lab.
2. The next quiz will be administered on Monday, April 16, 2007 at 12 pm covering the resolution step and the ligand synthesis. Please make sure that you show up on time.
ATTN: answers to the below questions are due at the start of your lab period; these answers should be part of your pre-lab write-up.
1. Penicillin V, phenoxymethylpenicillin, like most penicillins interferes with bacteria's ability to form new cell walls, which causes the bacteria to die. It is used for ear infections, inflammation of the tonsils due to infection (tonsillitis), and prevention against recurrence of rheumatic fever or prevention of pneumococcal infection. Before the compound is sold, its optical purity has to be determined. A lab assistant observes a optical rotation of a= +4.40o for a solution of 60 mg in 3 mL What is the optical purity of the sample?
2. Referring to the synthesis and characterization of the Jacobsen ligand, answer the following questions.
a. Why is potassium carbonate used in this reaction? Show pertinent equation(s).
b. Why should the aldehyde be added in excess to the solution prepared in a.?
c. Why is water added before the reaction mixture is allowed to cool down?
d. The two phenolic protons show at d= ~13.6 ppm in the 1H-NMR. Which conclusion can the student draw about the structure of the compound?
e. Which solvent is used to acquire the UV-Vis spectrum for the ligand? Which concentration is appropriate here?