322af07_e3_key

322af07_e3_key - mm {mm our 04% ( mm will 1% mime «‘ A...

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Unformatted text preview: mm {mm our 04% ( mm will 1% mime «‘ A 1W." M N?“ "31‘ a a e r P16 _______ e W Name NOVEMBER 28, 2007 an an “(a/m First Name K E Y First4digitsofUSCID ____-xx3o<-)o< M name of TA Grader (1) (6) __ (2) <12) __ __ e (3) <6) __ __ iflfififlflflfiflflflflfi ? __ r (4) (e) @fiflflfififimflfiflfiflflMfiflm — _ Hfififlflflflflflflfiflflflflfififl (5) (6) __ __ ' _Mflflfififlfifl ---- -- ‘6) (12) — — w- flflflfiflfiflfifififlfififlfl (7, (20) __ - mmmmmmmmmmmmm (8) (16) — AG =—RT1n(I<,.,) =—(RT/2.3)log(K,Q = l.4*pK,q (9) (16) _ AG = AH was Iii [products] / [reactants]; pKeq = PK. (fwd) - pK. (rev) (10)(35) __ __..__ E: Ze'igfigfl) (11) (15)__ E51 3:23;; 7 2(3.39/1: (150) __ __ first letter of last name I will observe all the rules of Academic Integrity while taking this exam. Signature Chemistry 322a/ 325a -2- Name: Third Midterm Exam 1. (6 pt) In each pair of compounds, circle the stronger acid (2 pt each). 0 3 H) with b, i? f9 if)" 2. (12 pt) For the indicated hydrogen atom, estimate the water-referenced pKa (2 pt each). Hm I<l~>Ll qo—wfi [Lb 4M" . . m f. e lg: #46 filarS 3. (6 pt) For each pair of structures, circle the compound that will react faster in an SNl reaction (2 pt each). amifvm 'III’.h4£7 (Egg) (‘III"€3&? 4. (6 pt) For each pair of structures, circle the nucleophile that will react faster in an 5N2 reaction (2 pt each). 30.. (1.. ..©::@ m 5. (6 pt) Estimate the TMS-referenced chemical shift (ppm in CDC13) for the indicated proton (TMS = SiMe4, 2 pt each). a .65” C, E Z 0.54%.; 'gaqlg All 07 Luau/0., lbflx Dang, Chemistry 322a/ 32521 -3- Name: Third Midterm Exam 6. (12 pt) In each pair of compounds, circle the one with the stronger bond, that is, the bond with the largest homolyfic dissociation enthalpy (2 pt each). H H E 1 l 1 w W 5L ,H ,H /OH a. O Q S '5 b. H H c. H30 0 K‘ HQH >_/ \ Mac] MCI MCI f. H30 (1 5‘ e, 7/1 7. (10 pt) How many signals (types of protons or carbons) do you expect in the 1H and 13C NMR spectra of these molecules (2 pt per box)? L OOH / N O OH (9 /L O /\ H HaN COS) \n/ Cl \ Cone 0 BHT alanine Aspirinm) vinyl chloride (a radical inhibitor) (an essential amino acid) (an analgesic) (a monomer for PVC) 1H 130 1H 13C 1H 130 1H 13C 1H 13C 8. (16 pt) What integration and coupling pattern do you expect for the indicated proton(s)? Do not forget to count any equivalent protons that appear in the same signal. Answer nH, (s)inglet, (d)oublet, (t)riplet, (q)uartet, (o)ther/ complicated. Assume that the integrations are normalized accurately to count all of the hydrogens in the molecule. The first is done for you (4 pt per box). H (10 “x 0%; @J’Lo’i 6} 1; . 1 2 91 wk {in 0,1“ 027, Chemistry 322a / 32521 —4— Name: Third Midterm Exam 9. ([6 pt) A compound of formula CWHM has the 'H and '3C NMR spectra below. Propose its structure. Partial credit will be given for partial structures, 6 pt per correct spin system. 200 180 160 140 120 100 80 60 40 20 O cus-oo-sn ppm Chemistry 322a/ 325a -5— Name: Third Midterm Exam 10. (35 pt) Fill in the missing starting material, product, or reagent from the synthetic schemes below. Be sure to include any stereochemical details that you are able to describe. Although it is not important to indicate the inorganic side products, indicate all of the organic products. Where applicable, indicate whether there is a major product or if materials are formed in a 1:1 ratio (5 pt each). gr .7) ' H 3“ Mal in 65 + Lgré-tBuOOHfiBr. J: l— mayoral/m i ’ A! ‘ a. L/ l M Sh (Ln tha{u(3 U 0 H 3” 0740le i. 03 fi ii. Zn, HOAc —’ "L ‘ CarmH \ 0 p raga“ ~f Z- Emmohydrrq,‘ 7\- {ugh} (Mm + Bra, H20 ‘2 “24¢; fin P l ‘ Annotate“, C. q )I‘ a! lw" ‘1" PL‘ 2 * 6%; (optopantrqa : E + CHCI3, tert-BuOK L / 1 - Aereocum Chemistry 322a / 325a —6- Name: Third Midterm Exam 11. (15 pt) When compound A below is heated in water, it rearranges to give a single product (either B or C, not both). Note that 4-bromophenylsulfonic esters (such as the one here) are good leaving groups. L O H (%— §-©~Br 20 OR . 0 heat ' OH b. Write a reasonable curved-arrow mechanism for the reaction. Show each bond—forming and bond-bé/fiking step distinctly (9 pt). S H O 0/6) (“Ha 07 @133 c. Describe the enthalpic driving force for this reaction with no more than 10 words (3 pt). ...
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322af07_e3_key - mm {mm our 04% ( mm will 1% mime «‘ A...

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