Week 7 Problem Set 30 BL (Coumarin Synthesis)

Useful Link: Refractometer

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.

Administrative Issues

1. Please consult your teaching assistant directly in order to find out when a particular post-lab report is due. The yellow reader outlines the tentative schedule, which has to be adjusted from time to time depending on how the section proceeds with the in-lab work.

2. If you have questions of general nature, please post them on the course discussion board instead of sending it to the instructor. Answering the same question several times is not productive for anybody.

3. The report for the project will be due by Monday, August 31, 2015 at 4:30 pm (in paper) and on the same day by 5:00 pm (on www.turnitin.com, CourseID: 10086582, Password: Chem30BL).

1. After watching the following video (MP4-format), reviewing the TLC and the HPLC chapter in the SKR and the reviewing the lecture material, take the online quiz.

Quiz: (http://bacher.chem.ucla.edu/TakeQuiz/?id=d3d9446802a44259755d38e6d163e820). The quiz is worth 10 points, and has to be taken until one hour prior to the in-lab meeting 7. (Hint: In some cases more than one answer is correct!) Even though you can take the quiz until one hour prior to meeting 7 of your section, you should not delay taking it since there might be some problems with the server. There seem to be problems with some MAC systems as well. After you submit the answers, your score should appear on your screen. If this does not happen, you will have to retake the quiz. (There will not be any possibility to retake the quiz weeks later!). In order to take the quiz, you have to go through a UCLA ICP address. This means that you either have to use your Bruin-Online account or go through the VPN (Vitual Private Network, software can be found here: http://www.bol.ucla.edu/services/vpn/) to have this UCLA ICP address. To log in, use your last name and your student ID. If you are experiencing problems, contact the instructor via email and include your full name (indicated which one is your last name), your student ID and section .

Prelab questions

1. a. What is the compound synthesized in the lab used for?

b. What is the first step of the Pechmann condensation carried out in the lab?

c. What is used as catalyst in the lab? Show the key intermediate.

d. Why is the heated reaction mixture isolated after the removal from the microwave?

e. Which solvent is used to isolate the compound?

f. The compound displays fluorescence. What is used as light source to excite the molecule? What would the student expect to observe?

g. The mass spectrum displays the base peak at m/z=148. Show the fragment that causes the appearance of this signal.

h. The ß-carbon (of the alkene function) to the carbonyl group is located at δ=155.3 ppm. Rationalize this observation.