Announcements (make sure to read them since you will held responsible to it)

1. The first quiz will be administered in lecture on Tuesday, April 6, 2010 at 12 pm (covering the introduction to asymmetric synthesis and the resolution step). It is the student's responsibility to arrive on time which means that you have to be there at 11:55 am!!!! Late arrivals (even if it is only one minute) will not be allowed to take the quiz, which means that you will receive an automatic zero score for the quiz. If you do not place your name on the quiz to assume authorship, you will receive a zero score as well! You cannot add the name after time was called because this is considered cheating.

2. The draft version of the paper will be due by Friday, April 23, 2010 at 4:30 pm in YH 3077E.

3. The instructor will not respond to anonymous emails. In other words, if you are not providing your name (not just some alias!) with the email, you will not get a response.

4. The questions below are due on April 1, 2010 or April 2, 2010 depending on when your lab section meets.

ATTN: answers to the below questions are due at the start of your second lab period; these answers should be part of your pre-lab write-up.

1. Referring to the resolution of 1,2-diaminocyclohexane (step 1), answer the following questions.

a. Provide a balanced equation for this reaction including the proper stereochemistry.

b. Upon addition of glacial acetic acid, the tartrate salt does not precipitate. What can the student do to promote the precipitation?

c. A student isolates 8.00 g of the crude tartrate salt. How much solvent should he use to recrystallize the crude? Which solvent is used here?

d. After recrystallization, he obtains 2.20 g of the tartrate salt. Determine the percentage yield for this reaction (assume that he used the quantities given in the reader) and comment on it. Show all calculations.

e. The procedure asks to use a concentration of 1-3% of the tartrate salt when acquiring the optical rotation. Rationalize this choice.

f. Assuming the specific optical rotation for the pure product is [a]= +12.5^o, determine the optical purity of a sample that exhibits a specific optical rotation of [a]= +11.8^o. Comment on the observed optical purity.

2. Referring to asymmetric synthesis, answer the following questions.

a. What are atropisomers? Give an example.

b. How do the two enantiomer of ibuprofen differ biologically speaking?

c. What does the abbreviation "e.e." stand for? What would be a desirable value?

d. How does a chiral auxiliary work?