Sample Questions for exam 2 Fall 2014 1. Draw structures corresponding to these names: a) (2 pts) para-bromotoluene b) (2 pts) 2,4,6-trinitrochlorobenzene c) (3 pts) (R)-3-methyl-3-phenylnonane d) (2 pts) meta-isopropylaniline 2. (12 pts) For each of the following structures answer the following questions: a) hybridization of the arrowed atom, b) total number of electrons in a closed conjugated system, c) indicate if the molecule is aromatic (a) , non-aromatic (na) or antiaromatic (aa).3. (4 pts) Using the templates provided draw two different additional resonance structures for pyrene and indicate with curved arrows their relationship to the original structure provided. 4. (4 pts) Imidazole can behave both as an acid and a base. Write the structure of the conjugate acid. Make sure to show lone pairs of electrons and formal charges. 5. (6 pts) Identify which compound in each pair is more reactive towards Electrophilic Aromatic Substitution, circle the letter of your choice.6. (6 pts) On each of the substituted benzene rings indicate with an arrow which position is the most likely to be substituted in an Electrophilic Aromatic Substitution reaction. If there are two positions equivalent indicate only one. 7. (8 pts) Write the complete stepwise mechanism for the sulfonation of toluene on its ortho position. Use curved arrows to indicate the movement of electrons; make sure to show all lone pairs of electrons and charges where appropriate. Show all possible resonance structures of the carbocation intermediate and circle the most stable. (Hint: Some of the basic steps in the mechanism include: formation of the ionic intermediate and regeneration of the aromaticity).8. (10 pts) Provide reagents for the synthetic sequence below. NO2COOHNO2COOHNH2COOHNH2SO3H 9. For the Nucleophilic Aromatic Substitution of 2-chlorobenzonitrile with NaOH. a) (4 pts) Write the structure of the initial charged intermediate and the structure of its most stable resonance structure. b) (1 pt) What other substituent could have been in place of the –CN to achieve a similar type of reaction? 10. (3 pts) List three basic requirements for a compound to be considered aromatic. a) b) c)11. (10 pts) Select the reagents, in the appropriate sequence, to synthesize the target product below from the starting material indicated. Assume that you can separate ortho and para isomers if necessary. If less than five steps are necessary enter “none” in the last box(es). Show the structure of the intermediate products obtained in each step. A) CH3CH2COCl, AlCl3B) H2,Pd C)Cl2,FeCl3D) CH3CH2Cl, AlCl3E) BH3,THF;thenH2O2,-OH F) Br2,CH2Cl2G) N-bromosuccinimide, (PhCO2)2H) (CH3)2CHCOCl, AlCl3I) KOH, ethanolJ) HNO3,H2SO4K) CH3COCl, AlCl3L) Fe, H3O+,then-OHM) KMnO4,H2O N) MCPBA O) SO3,H2SO4P) CH3CH2CH2Cl, AlCl3Q) (CH3)3CCl, AlCl3R) LiAlH4,thenH3O+S) Hot dilute H2SO4/H2OT)H2/Rh/C1atm U)Br2,FeBr3 OHtarget product12 (10 pts) Give the major products for each of the following reactions. If no reaction is predicted, write “N.R.” If more than one major product is expected draw it on the right of the box.13. (7 pts) Starting with Benzene and using any other necessary reagents of your choice, design a synthesis for the following compound. There may be more than one plausible answer. 14. (6 pts) a) How many non equivalent H’s does the following structure have? OCH3OCH3 b) How many non equivalent C’s does the following structure have? OCH3OCH3 c) Which of the protons highlighted in the molecule below appear furthest upfield in the NMR spectrum (i.e. to the right of the signal of TMS)? (Circle your choice)15. Draw structures corresponding to the following names: a) (2 pts) 4-phenylbutanal b) (2 pts) 2,5-heptanedione c) (2 pts) cis-2,4-diethylcyclopentanone 16. Provide the reagents necessary for the following transformation: (3 pts) 17. Draw the structure of a starting material suitable to complete the following reaction. (3 pts) © P.Santander / Fall