Problems Set (Meeting 10)
General Announcements
1. Make sure that you turn in a hardcopy of your research paper by February 15, 2008 at 5 pm and the electronic version to turnitin.com as well (CourseID: 2170988, Passwd: Chem30CL for Winter 2008). Late reports will be deducted points (10% per day including the weekend). If you do not submit the report online by Monday February 18, 11 pm, you will receive a "zero" score for the paper. In addition, it will be reported to the Dean of Students. Any plagiarism, partial or full resubmission of a papers or/and other forms of cheating will result in a report to the Dean of Students as well. Make sure that you cite your sources and try to use your own words as much as possible. Here is a checklist what should be included into the report. If you have any questions, please contact your TA or instructor asap, and not an hour before the submission deadline.
2. The next quiz (=quiz 4) will be administered on February 7, 2008 at 12 pm and will cover the entire Lidocaine project. Make sure that you show up on time. Otherwise you will not be allowed to take the quiz.
3. The postlab report for the lidocaine project has to be written in the lab notebook and submitted to the teaching assistant. The due dates are February 19 or 20, 2008 in your section.
4. The final product has to be turned in to the TA by February 13, 2008 at 5 pm for evaluation by the instructor. Late submission will not receive any credit. Make sure that you label the vial properly. At some point in the work-up, concentrated potassium hydroxide solution is added. Explain why and show the pertinent equation.
Questions
1. Referring to the conversion of a-chloro-2,6-dimethylacetanilide to licocaine, answer the following questions. Show pertinent chemical equations.
a. Why is it important that the a-chloro-2,6-dimethylacetanilide is as dry as possible for this reaction?
b. The procedure asks for three equivalents of diethylamine. Explain.
c. Why is the reaction refluxed for 90 minutes?
d. During the work-up, the reaction mixture is extracted with 3M hydrochloric acid. Which purpose does this extraction serve? In which layer is the product after the extraction?
e. At some point in the work-up, concentrated potassium hydroxide solution is added. Explain why and show the pertinent equation.
f. Why is the product redissolved in hexane after being isolated in e.?
2. Amides
a. Why does the 1H-NMR spectrum of many amides change as the temperature of the solution changes?
b. Acetamide boils at 222 oC, while N,N-dimethylacetamide boils at 165 oC. Rationalize this observation.
c. What are the differences between a primary amine and a primary amide in the IR spectrum?