322bf07_e2_key - CHEMISTRY 322bL Please k9 i EXAM NO 2...

Info icon This preview shows pages 1–10. Sign up to view the full content.

View Full Document Right Arrow Icon
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 4
Image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 6
Image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 8
Image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 10
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: CHEMISTRY 322bL Please k9 i EXAM NO. 2 Print Last Name OCTOBER 8, 2007 First Name First four digits of USC ID _ _ _ _ -xxxx-xx TA's Name Grader (1) (15) __ (2) (15) __ _ (3) (10) _ _ (4) (15) _ _ (5) (10) _ __ (6) (10) __ _ (7) (10) _ _ (8) (15) _ _ (100) Lab Day 8: Time first letter of last name I will observe all the rules of Academic Integrity while taking this exam. Chemistry 322bL -2- Name Ex N .2 am 0 3% (1) (15) Complete the reactions below by providing the missing products inside the boxes. Be careful to give all the important organic products, as requested It 1s not necessary to give the byproducts or minor products of the reactions. Workup means treatment with water and bringing the reaction mixture to neutral pH. OOH “6"" 1. fl any (1) HNO3, H2504, heat © 0114A “atom, (A) (ii) workup HzCH3 (i) Brz, Fe (3) (ii) workup ””115 H3 3 ' CH Cl/AlCl (C) (I) 3 3 CH3 (ii) workuw jot M cu '4 C . M one malor product: CIOHIZO c (Ct—(3)3 (D) @ + H3Cjc=cr12 HF © H3C 0°C large excess H2CH3 P cu Bra-43 o E hv ( ) + /N-Br C (:14 Q IU~ t-t \\ + O t . D . an aromat1c a nonaromahc product product Chemistry 322bL Name -3- E amNo.2 x 3 £46k f“:— (2) (15) Complete the reactions below by providing the missing products inside the boxes. Be careful to give all the important organic products, as requested. It is not necessary to give the byproducts or minor products of the reactions. "Workup" means treatment with water and bringing the reaction mixture to neutral pH. 3 lfitaflm (i) I'iNO3, H2504, heat 0 r - W, «A ) NO i) workup CH {wot W 3 (i) Na, liq NI-I3, trace EtOI-I, —78°C (ii) workup 54.“ M \ \ W ;Q(C;:;:IEH= —CH2 + HBr no peroxides + Li AlH(O—Bu-t)3 ethyl ether, -78°C (i) CH3CH2CH2CH2MgBr/ ether (ii) H3O+, H20, heat Chemistry 322bL —4- Name Exam No. 2 (3) (10) Answer the following questions about the Huckel rule and "aromaticity." (A) (3) What is the "Hiickel rule" and to what type of structures does it apply? I CGfchcu‘ “3TH“ LLl'K-t—IB/fl" (\‘C'l'TD'KX CerNCQ‘Ot-fim'fi‘g’) chrt M \S OJIJZJ3—-—° Tk" PU“- ‘spplfis +0 Q\¢~N6‘ S+Pug+u r13 UlN‘H‘L QCLQK CCIJ‘bO’K is 5'91 L7 br-E‘LI'Lv—d. (B) (2) In each pair of ions below (I/ II and III / IV), circle the ion that is "aromatic" according to the Huckel rule. H H H H .l/A“ H H 11 IV (C) (5) For ions I and II, use the polygon inside a circle method to estimate the relative energies of the n-MOs in each structure. Show the approximated MO energy levels by horizontal lines in diagrams to the right below. Use up/ down arrows to indicate orbital occupancy. Circle the more stable n-electron configuration and indicate why it is more stable in the shadow box below. approximation of 1: MO configurations ll relative 1t electron inscribe polygon inside circle above '1: \s q Q\es¢<l stun $151: w\ LJch-c. be e\c_c_-4u-o~\s cura— Wm aL 5+‘b-‘M‘LL'KS Mo . Chemistry 322bL -5- Name Exam No. 2 (4) (15) Answer the questions below. (A) (6) Provide structural formulas for the names below the boxes. 0H (5x 1/ N02, p-nitrophenol 3-chloro-4-methylbenzoic acid 1-chloro-4-methyl-2-pentanone (B) (6) Draw in the boxes below all the resonance structures of the arenium ion intermediates for the competing pathways of meta and para chlorination of toluene. Provide all the detailed resonance structures of the arenium ion intermediates above. (C) (3) With reference to the above resonance structures, briefly explain why this reaction provides more para (and ortho) product and less meta product. Be specific! \‘K Para afiat‘, *‘L‘L “so—Kamck S'k—ruck-uvscs 0(— ~\—\\g QNM\0W\ tam SkocoS FSS‘rHUQ Chm-31 Om fks 1"th Cur—Bow #40:“ 'H'“ W+k7§ and (F LULxILKRS RVLM’Kf‘ADN H’Kfi\ This Gem-“VOW \DW\ ‘\3 S‘l'I—Mzk‘c'Lf-‘L& ‘31 TLL ML+k7I jr'oufi: UL‘;\¢ T'k‘L Qt—orv-xiuk lon“"Q*‘\ NI. 4‘ CL‘H‘IL pk LIQS- «0 80 c,(/\ whtl;b-Lfl4 Chemistry 322bL k —6- Name Exam No. 2 2.. “0 (5) (10) Circle the correct answer for each question or statement below. (A) Among the mono— —substituted benzenes below, the meta product will dominate 1n the nitration reaction with (circle answer below) I, III, IV II,III III only III (B) The faster reIacting mono-substituted benzene' 1n each pair below in the bromination reaction (Brz/ Fe) is NH2 HgCI-I3 CH3 8CH3 (circle answer below) A I, B I AII,BI AILBII I II I II A B (C) In each reaction below, the major product will be H H+/heat (i) C6H5CHngCH3 ——> C6H5CH=CHCH3 0r CGHSCH2CH=CH2 (-Hzo) I (as a mixture of II E and Z isomers) Br (ii) C6H5CH=CH2 + HBr —," C5H5CHCH3 0r CeHSCHzCH23r perox1des I II (circleanswer) (i) I, (ii)I (i) ll, (ii)I (i) 11, (ii) II (D) In each pair of alkyl bromides below, an 8N1 reaction will proceed faster with (Circle answer below) 1 r - @ é C6H5CH2CHCH3 C61+15c1+1c1+12c1+13 ALBI @ 11 AII,BI AII,BII A B (E) Which of the following reactions of ethylbenzene involve a chemical change in the side chain (the ethyl group)? C12,hv, heat CH3COC1/ A1C13 hot aq. KMnO4, KOH fuming H2504 I II III IV (circle answer) I, IV a only III I, II, III Chemistry 322bL -7— Name Exam No. 2 (6) (10) Answer the questions below. (A) (5) Although the enthalpy change for the hydrogenation of benzene to cyclohexane is very exothermic (see below), this reaction requires "forcing conditions" of high pressure and high temperature, unlike the facile hydrogenations observed with alkenes and alkynes. Provide a clear and specific explanation that includes intermediate products. very slow Ni AH° = -49 kcal/mol high pressure and high temperature r‘ H ,. TE \3 JL—Ado‘l-Nrk.‘ K Lu. «JekA Cka—wse A '|_ > L; ug-Sd 0C Plkk \ ° Q’V—V Shh: L33 “ng Q_~\¢ Pskq e-e LC: mfii-c‘c baa/K10“ , TWAL °‘\r~'\'l’\¢-\P" c «as-‘3 2 1‘?er a—wi “L“ 9E CLVV. bow H} Sk\7 Q fito‘K'kov-Wtq \2 GLA‘V‘AS +5 Jrkg ambut Ale 2; .qukgt "Writ—S700 S—‘Efp is 11—91::- No (B) (5) While the nitration of benzene proceeds very slowly in hot concentrated nitric acid, this reaction proceeds at a good rate when concentrated Sulfuric acid is added. Explain this observation with chemical equations that show formation of the reacting electrophile. Tka. Q-H—mgkgtmi «\y-qh-o Phils 1'5 +kgmtmegu! (om -, NOL®' TlArs \o~\ t3 PNAVCQ ’31 ‘l‘\~( a. 921— Fr‘omo‘t‘itcd da.\p7 Arm-Ham or? “70+r-Tc “64-1 £3. 3 : 633‘- " “ +HoSoH Q lib—@2526; +— H$O3® “9—5229 Ab '4 I Chemistry 322bL -8- Name Exam No. 2 (7) (10) Heterocycles are cyclic structures where a "hetero atom" such as O, N or S replaces C. Furan (I) is an "aromatic" oxygen heterocycle that shows reactivity towards electrophiles similar to phenol, C6H50H. For example, furan reacts with Brz (no catalyst needed) to produce 2-bromofuran. / \) + HBr fast Br .9. 2-bromofuran (A) (6) Write out a plausible mechanism for this reaction using the curved arrow formalism Hint: Consider a two-step mechanism similar to electrophilic substitution 1n DLKocolt'u-d. CQHOM 247 (mfirmifa'hk Mm‘k MM (frat 1‘0 ky/nl’wy (B) (4) Draw a series of resonance structures for the key intermediate in the box below. Chemistry 322bL -(9)- Name Exam No. 2 (8) (15) Provide reasonable and efficient syntheses of the compounds below from the indicated starting sources. H3 and any needed (A) (5) reagents --------- -> CH-n, © (1\ KHMDV‘KO-H [115* fif‘z @ (h) \¥30 ® F“; /’ B Part (B) is on the next page. Chemistry 322bL -(10)- 0 Name Exam No.2 —— Q («X (64-3 CtkKlfl-E'C/ “AL (8) Contd. 142 £016 ,4 ”oak/{2 6416M (cum. and any other needed (B) (10) organic compounds and reagents MCI Hint: Consider the route shown to the right, with benzene -------- - C6H5CHBrCH2CH2CH3 -------- » 1 a key cuprate coupling step. C? 09 +_ (H304 talk: \ —-’——’=) 2&1 /' 4 K07 ‘ “We / Q9939 H‘s cue Hzeu§r+CH5 \ijx e g.__ ...
View Full Document

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern