1. General

a. Make sure that you get all the assigned texts and that you read them as thoroughly asap. If you have questions, please consult your TA or the instructor before you attend the lab.

b. You also should start writing the introduction for your formal report. It could not hurt either to write up the experimental and the discussion part as you go along with the project. There are no post-labs due for this project since the formal report replaces those.

c. Review the following subjects: resolution, optical purity, polarimetry, organization skills!

2. Experimental (Resolution of the diamine)

a. It is important that the diamine is added slowly. Why?

b.The desired product crystallizes together with some trapped material, hence you will need to recrystallize the crude product.

c. The Hanson paper suggest to recrystallize the crude product from hot water (~1 g dry material/10 mL water=1:10 w/v). Since the isolated crude product is not completely dry at this point, a ratio of ~1:3-1:5 (w/v) might be a better starting point, since it is easier to add water than removing it. The solubility of the salt increases dramatically towards the boiling point of the solution! The addition of too much water has to be avoided here since it takes a long time to remove!

d. It is crucial that the final product is isolated before leaving for the day. Why?

e. The final product should be white or off-white after recrystallization.

3. Experimental (Oxidation of benzylic alcohol with DMSO/HBr)

a. It is important to keep the temperature of the reaction mixture around 95 ^oC +/-5 ^oC (boiling water bath). If the temperature was too low, the reaction will slow down.

b. Since the reaction will require two hours, it is highly advisable to get started with it right away. It might be also a good idea to monitor the reaction using TLC. Which solvent should be used?

c. Warm methanol (~ 50 ^oC) is used to recrystallize the crude aldehyde. Why? Again, the crystallization should be initiated before leaving for the day!

3. Things to think about

a. How can you isolate the (S, S)-form of the diamine mixture provided in the lab?

b. What is the maximum yield (in % and grams) for the tartrate salt assuming that you use the commercially available mixture described in the reader?

c. Suggest a different way to separate the different enantiomeric forms in preparative scale.

d. How can the optical purity of the tartrate salt be determined?

e. Why is a high degree of optical purity of the salt desirable for the rest of the project?

f. Why is the value for the optical rotation of the free (R,R)-1,2-diaminocyclohexane different from the one for the tartrate salt isolated in the lab?