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CHEMISTRY 212 EXAM 2 Friday, February 13, 2004 Answer Key 1. (12) State whether each of the following is aromatic or non-aromatic. In addition, give only the following data which enabled you to arrive at your conclusion: fully conjugated - yes or no; # pi-electrons. a) b) N c) N O N aromatic; fully conjugated – yes electrons 6 pi electrons aromatic; fully conjugated – yes non-aromatic; 6 pi 6 pi electrons not fully conjugated 2. (7) In each example shown, circle the benzene ring most likely to react with an electrophile. You need not explain your answer. O a) b) O2N O CH3 HN 3. (12) State whether each of the following molecules is activated or deactivated compared to benzene. It is not necessary to explain why. O NH a) b) activated C c) CH 3 deactivated O activated d) OH deactivated 4. (12) State whether further electrophilic substitution of each of the following molecules would occur in the ortho / para or meta positions. It is not necessary to explain why. O O H a) b) c) d) S N Br N NH2 CH3 meta ortho / para ortho / para meta 5. (8) Show the first step (complete) of the arrow-pushing mechanism for the reaction between each of the following: O a) OH S Cl Cl b) 6. (14) Synthesize the following starting from benzene or toluene. Show all steps and reagents. Br a) NO2 1) Cl2 / FeCl3 2) HNO3 / H2 SO4 and remove ortho 3) Br2 / FeBr 3 CH3 b) Cl COOH 1) CH3COCl / AlCl 3 2) remove ortho product 3) KMnO 4 / H2 O, heat H3C C O 7. (3) One diagnostic feature in the NMR spectrum for alcohols is that on addition of D2O the signal for the OH: a) increases in strength downfield b) becomes a doublet c) moves upfield d) disappears e) moves 8. (6) Classify the following reagents as oxidizing or reducing. a) KMnO4 oxidizing b) PCC oxidizing c) NaBH4 reducing 9. (5) Draw a Grignard reagent and carbonyl compound that could be used to form the molecule shown: OH from CH2 MgBr and O 10. (10) For the compound shown below, show all the resonance forms that illustrate the effect of the group attached to the ring. In this case, you should show arrow-pushing to support your answer. O OH O OH O OH O OH 11. (4) Draw the carbonyl compound that could be reduced by NaBH4 to form the molecule shown: OH from O 12. (32) Show reasonable products, or missing reactants, for the following reactions. a) H OH 1) PhCH2 O MgBr 2) H+ b) O 1) LiAlH 4 OH c) OH 2) H+ OH OH CrO3, H2SO4 O d) H PCC OH e) O H2SO4 + cis OH Br O f) Ph H2 Ph NBS Ph Pd Ph heat Ph Ph 13. (3) True or False? The molecule shown would react with NBS. 14. (3) True or False? In the Friedel-Crafts' alkylation shown, rearrangements would not be a problem. + Cl AlCl3 15. (3) Which one of the following compounds reacts most slowly with HNO3/H2SO4? SO3 H NH2 Cl 16. (4) Which of the following is the best method of preparing meta-nitrobenzoic acid from benzene? a) CH3Cl with AlCl3; then KMnO4; then HNO3 / H2SO4 b) CH3Cl with AlCl3; then HNO3 / H2SO4; then KMnO4 c) HNO3 / H2SO4; then KMnO4; then CH3Cl with AlCl3 d) HNO3 / H2SO4; then CH3Cl with AlCl3; then KMnO4 17. (4) Which of the following sequences gives the compound shown at the left in the highest yield? CO 2H N O2 Br a) CO 2H b) CO 2 H HN O3/H 2SO 4 Br2 /F eBr3 Br 2/FeBr 3 HN O3/H 2SO 4 c) C H3 d) C H3 Br 2 /FeBr 3 H NO 3/H2 SO 4 HNO 3/H2SO 4 Br 2/FeBr 3 KMnO 4 , KMnO 4, D would be the best choice 18. (4) Which one of the following alcohols is oxidized to a ketone by Jones reagent? CH3 OH CH 2OH OH OH 19. (4) Which of the following reactions do not occur? More than one answer may be possible. a. Benzene + Br2 in the presence of FeBr3; b. Nitrobenzene + 1-chlorobutane in the presence of AlCl3 c. PhCO2H + CH3COCl in the presence of AlCl3; d. Toluene + HNO3/H2SO4 Neither B nor C would occur