FALL 2018 CEM 251: rganic Chemistry I Sections 25-36 TUE-TU 8:00 9:20 AM September 25, 2018 ame: Section: PID: TA: This is a closed book and note examination. If boxes are provided for your answers, only what is written in the boxes will be graded. You have 80 min to complete the test. Section 25 Thu 10:20 11:10 AM Shuyao Section 26 Thu 10:20 11:10 AM Dan Section 27 Mon 12:40 1:30 PM Dan Section 28 Mon 9:10 10:00 AM Dan Section 29 Tue 10:20 11:10 AM iloofar Section 30 Thu 1:50 2:40 PM Shuyao Section 31 Thu 4:10 5:00 PM Shuyao Section 32 Tue 3:00 3:50 PM iloofar Section 33 Tue 4:10 5:00 PM iloofar Section 34 Thu 4:10 5:00 PM Shuang Section 35 Thu 3:00 3:50 PM Shuang Section 36 Thu 1:50 2:40 PM Shuang Question Points Score 1 10 2 18 3 6 4 4 5 18 6 16 7 8 8 10 9 10 Total 100 1
1. Provide a name or a structure for the following compounds (10 pts, 2 pts each box). a. cis-3-ethyl-1-(2-methylpropyl)cyclooctane b. c. 3-cyclpropyl-2-ethyl-5-(1-methylethyl) nonone d. e. 2
2. What orbitals are used to form each indicated bond? (For multiple bonds, indicate the orbitals used in each individual bond) (18 pts, 2 pt/box) 1st bond: 2nd bond: F CF 3 1st bond: 2nd bond: 3rd bond: S Cannabinoid Receptor 2 Photoaffinity Mimic 3. Assign formal charges and indicate the number of lone pair electron to the indicated atoms (6 pts, 2 pt / box). umber of lone pair: Formal charge: umber of lone pair: Formal charge: umber of lone pair: Formal charge: intedanib metabolites 3
4. Please cross the structure that is not a constitutional isomer of the other two structures. (4 pts, 2 pts/question) A. --------------------------------------------------------------------------------------------------------------- B. S S S 5. Please draw 3 valid resonance structures for each of the following molecules (18 pts, 2 pts/ box) A. 2 2 4
B. C. 5
6. Ibuprofen (Motrin) is a common non-steroidal anti-inflammatroy drugs (SAIDs). It is poorly soluble in water. In order to increase the solubility of Ibuprofen, corresponding conjugate base (ionic form) is usually prepared for studying their enzymology with an enzyme called cyclooxygenase. A. Please circle the most acidic proton in ibuprofen (2 pts), indicate the equilibrium of the following acid-base reaction and draw the structures of corresponding conjugate base and conjugate acid. (6 pts, 2 pts per box) indicate the equilibrium + + ibuprofen (Motrin) pka = 4.85 conjugate base conjugate acid pka = 15.7 B. Please draw the arrow-pushing mechanism of the above acid base reaction. (4 pts, 2 pts/ arrow) + conjugate base + conjugate acid (This arrow has no indication whether it is a forward or backward reaction) 6
C. Please draw all the possible resonance structures of the carboxylic acid ( ) of ibuprofen. (4 pts, 2 pts per box) and circle the lease stable resonance structure (2 pts). 7
7. Rank the following highlighted based on their acidity (8 pts, 2 pts per box). F F A B C D Most Acidic > > > Least Acidic 8
8. Draw the chair conformations of below line-bond structures and corresponding ring flipped structure. (8 pts, 2 pts per box) Circle the most stable constitutional isomer. (2 pts) ring flip ring flip 9
9. Please draw the ewman projection (From C3-C4) of the following structures. (10 pts, 2 pts per box) A. 1 2 3 4 5 6 Cl ewman Projection From C3 to C4 rotate 60 B. rotate 120 ewman Projection From C3 to C4 rotate 120 rotate 120 Cl 1 2 3 4 5 6 10
Scratch Sheet: eeds to be turned in with the test (if missing, the test will not be graded) 11
12