Chemistry 14C Winter 2017 Final Exam Part B Page 1

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1 Chemistry 14C Winter 2017 Final Exam Part B Page 1 Please use the backs of the data table pages and other exam pages for scratch space. Please do not use the exam margins for this purpose. Begin this exam by gently removing data table pages. othing on these pages will be graded. These pages will be discarded prior to grading. Ibudilast is an anti-inflammatory drug with bronchodilator, vasodilator, and neuroprotective effects. It is also being studied at UCLA for use in reducing methamphetamine and alcohol addition. In final exam part B questions 1 5 we explore the molecular structure of ibudilast and methamphetamine. CH 3 H CH 3 Ibudilast Methamphetamine 1. (2) Write the names of all functional groups present in either ibudilast or methamphetamine, but are not part of a ring. 2. (2) Write a number in the blank. Ibudilast contains lone pairs. 3. (2) Circle all conjugated atoms in ibudilast. Do not circle any atoms that are not conjugated. 4. (4) In the boxes below draw two additional ibudilast resonance contributors. Make the contributors as significant as possible. Include all lone pairs. eatness counts, so you might want to practice drawing elsewhere before putting your final structures in the boxes. ote the alkyl groups, which are not involved in resonance, have been abbreviated as R and R' for simplification. R' R Contributor A Contributor B Contributor C 5. (1) In the blank write the letter (A, B, or C) of the most significant resonance contributor from question 4: Page 1 score =

2 Chemistry 14C Winter 2017 Final Exam Part B Page 2 6. (2) Complete this drawing of the ibudilast resonance hybrid by adding all partial pi bonds and any lone pairs not delocalized by resonance. Do not include any δ + or δ - charges. You may to consider some resonance contributors that you did not draw in question 4. R R' 7. (2) Which molecule is more likely to be colored? Write 'I' in the answer blank if the answer is ibudilast, 'M' for methamphetamine, 'B' for 'both', or 'C' for 'cannot determine. Answer: A 8. (2) In the answer blank write the letter of the indicated bond having the highest barrier to rotation. Answer: B C 9. (5) Aromaticity is an important property of pharmaceuticals, because it can control the molecule's structure as well as how the drug is metabolized. Here we determine if ibudilast is aromatic. (a) Write a number in the blank. The entire ibudilast molecule has pi electrons. (b) Write 'Y' for yes, or '' for no in each blank. Does ibudilast meet the p-orbital loop requirement for aromaticity? Does ibudilast obey Hückel's rule? Is ibudilast aromatic? CH (1) eatly and clearly label each methamphetamine stereocenter as R or S. Unclear or imprecise labels will earn no credit. H CH (3) In the boxes below, draw the requested structures. If the requested structure is not possible, write "X" in the box. eatness counts, so you might want to practice drawing elsewhere before putting your final answer in the box. Methamphetamine enantiomer Methamphetamine diastereomer Page 2 score =

3 Chemistry 14C Winter 2017 Final Exam Part B Page (1) Write a number in the answer blank. Including the structure shown on the first page of this exam, there is/are ibudilast stereoisomer(s). 13. (1) In the answer blank write 'Y' for yes, or '' for no. Stereoisomers of a drug can have different biological or drug properties: 14. (1) In the blank write the letter (a d) of the correct answer. Another correct name for the ibudilast structure shown on the first exam page is (a) (-)-ibudilast; (b) (+)-ibudilast; (c) neither of these; or (d) cannot determine. Answer: 15. (2) Complete this structure of D-glucose. eatness counts, so you might want to practice drawing elsewhere before putting your final answer here. H C C C H 16. (3) Complete this drawing of β-d-glucopyranose. Clearly and precisely label the anomeric carbon(s). If there are no anomeric carbons, write "no anomeric carbons". eatness counts, so you might want to practice drawing elsewhere before putting your final answer here. CH 2 H 17. (2) Complete this drawing cysteine, one of the twenty standard amino acids. eatness counts, so you might want to practice drawing elsewhere before putting your final answer here. CH 2 SH 18. (2) Complete this statement by adding no more than fifteen words: Cysteine is unique, or one of only two among the twenty standard amino acids because cysteine (2) Complete each statement by adding no more than fifteen words of explanation in each case. The explanations must be different for each part. Be precise and specific. Cysteine's side chain ( CH 2 SH) cannot be a hydrogen bond donor because... Cysteine's side chain ( CH 2 SH) cannot be a hydrogen bond acceptor because.. Page 3 score =

4 Chemistry 14C Winter 2017 Final Exam Part B Page (2) Write 'Y' for yes in each blank, or '' for no: Cysteine has a hydrophobic side chain: Cysteine has an acidic side chain: Lorenzo's oil has been used to treat adrenoleukodystrophy, a genetic disease. The oil gained widespread publicity due to the 1992 film Lorenzo's il. The oil consists of about 20% of the lipid shown below. CH 3 (CH 2 ) 7 CH=CH(CH 2 ) 11 (CH 2 ) 11 CH=CH(CH 2 ) 7 CH 3 (CH 2 ) 11 CH=CH(CH 2 ) 7 CH 3 Lorenzo's oil lipid 21. (2) By writing no more than twenty words, provide a precise yet concise definition of lipid. ote this definition has two essential parts. 22. (2) In lecture we learned of seven general lipid categories. To which of these categories does the Lorenzo's oil lipid belong? 23. (2) Complete the statement by writing the name of one of the seven general lipid categories in the blank, and then add no more than ten words of explanation: The Lorenzo's oil lipid is not an example of a because the Lorenzo's oil lipid (8) For each set of molecules, write the number of the molecule with the highest boiling point in the answer box. Choice 1 Choice 2 Choice 3 Choice 4 Answer Box (a) LiF ClF CH 3 F F 2 (b) F 2 FCl FBr FI (c) CH 4 CH 3 H CH 3 CH 2 H HCH 2 CH 2 H (d) F 2 Cl 2 Br 2 I 2 Page 4 score =

5 Chemistry 14C Winter 2017 Final Exam Part B Page (8) For each set of molecules, write the number of the most acidic molecule in the answer box. Choice 1 Choice 2 Choice 3 Choice 4 Answer Box (a) CH 3 H H H H (b) HF HCl HBr HI (c) HF HCl HBr H 2 (d) H 2 HF H 3 CH 4 Questions 26 and 27 refer to this DA nucleobase: H H (3) In each blank write the letter of the best answer from among the given answer choices. This nucleobase is part of. Answer choices: A, C, G, T, or U. This nucleobase is a. Answer choices: (a) purine, or (b) pyrimidine This nucleobase is. Answer choices (a) aromatic, or (b) not aromatic 27. (1) Complete each sentence by writing a number in the blank: This nucleobase forms a Watson-Crick base pair involving hydrogen bonds. Page 5 score =

6 Chemistry 14C Winter 2017 Final Exam Part B Page (32) Deduce the structure that corresponds to the spectral data on pages 6 8. Write your final answer in the box. A correct answer is worth full credit. If the answer is incorrect, your analysis of the spectra can be worth significant partial credit, so show your work clearly in the space below each set of data only. Answers outside of these places will be ignored. Final Structure Box (3) Mass spectrum: m/z = 232 (M; 100%), m/z = 233 (18.11%), and m/z = 234 (0.64%). o fluorine or iodine. Important hint: The molecule has no more than six DBE. Write in the box the **one** formula that is consistent with the mass spectrum, and is not rejected due to other reasons. Page 6 score =

7 (12) IR: Chemistry 14C Winter 2017 Final Exam Part B Page cm cm cm -1 IR workspace: 3000 cm cm cm cm cm cm -1 Page 7 score =

8 Chemistry 14C Winter 2017 Final Exam Part B Page 8 Anything written outside the boxes on this page will be ignored. Write only 1 H-MR implications in the 1 H-MR implications boxes and 13 C-MR conclusions in the 13 C-MR box. (12) 1 H-MR: Chemical shift Splitting Integral # H Implications ppm multiplet ppm singlet ppm singlet ppm triplet ppm sextet ppm triplet 3.0 (2) 13 C-MR: 208 ppm (singlet), 128 ppm (singlet), 126 ppm (doublet), 126 ppm (doublet), 125 ppm (doublet), 53 ppm (triplet), 42 ppm (triplet), 30 ppm (quartet), 28 ppm (singlet), 18 ppm (triplet), and 15 ppm (quartet). Page 8 score =