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Spring 07 Exam 2 Blank - CHEMISTRY 225 TEST#2 1(15 2(13...

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Unformatted text preview: CHEMISTRY 225 TEST #2 MAY 25, 2007 1. (15) 2. (13) NAME I _ 3. (19) G 0 O D L U C K I 4. __ {14) Useful atcrnic numbers: H =1,C = 6, N 2 7, O = 8, Si = 14, (31:17, Br 2 35 5. (14) TOTAL (75) 1. {15 Peints) CYCLIC COMPOUNDS. a. ( I 8) Cyclepentene, structure helew, is cne ef the simplest cyclealkenes. I (5) Write structural fermulas fer all derivatives cf cyclepentenc with a methyl greup as the enljvr substituent. D cvclenentene weahlyI acidic isemer I (l) Identifyr the isemer that weuld exhibit the fewest lines in its 13C NMR spectrum I (2) Write a structure fer a weekly ecidie isemer cf cvciepentene. h. ( .r' 2) A tetal synthesis cf butylcvcleheptvlpredigiesin, the cemples. pelycyclic cempeund tn the right, was achieved recently by a chemist at Beehringer Ingleheim Pharmaceuticals [Org Lett. 2007:, 91 1879]. Suggest a reasen why the name ef this ccmpeund seems te Pnnflir‘tf with its stmetnre. Etutvlcvclehep’rvlprcdigiesin 2 c. [ f 5) The preperties ef the unusual unsaturated hydrecarhen te the right were studied recently [Tetrahedren Len. 2007,48,35791 I (2) Determine the number ef signals (lines) in the 13C NMR spectrum ef this cempeund, I (3) Acceunt fer the high degree ef strain in this cempeund en the greunds ef structure and bending. HINT: censtruct a medel. 2. (13 Peints) ROTATIUNAL ANALrstn. a. ( i 9 ) Censider bend retatien in 3,4—dimethylhexane. I (-4) Preside Newman prejectiens fer the three staggered cenfermatiens ef 3,4—dimethylhesane leeking dewn the CEO—(3(4) cevalent bend. I (3) Circle the mess: stabie retatienal isemer and hrieflsr defend yeur cheice. a a I: I (2) Write a structure fer an isemer ef 3,4-dimethylhexane with three structurally unique (nenequivalent) carhen atems. CBHm structural isemer 3 b. { i 4) One ef the few urgauic reactiuus that alkaues undergu is phetechemical halegeuatiun, a reactieu in which a halugeu replaces a hydregeu upun irradiatiun with ultraviulet light {symbuiised as his). Cemplete the phetuchemical chleriuatiun reactiuu beiuw with structures fer all muuechleriuatieu pruducts {Cal-113L731). lguere the side product, HCI. w cr-tachHCH3 + cs _1w_,_ CH3 3. (19 Peiuts) ORGANIC REACTIONS. at ( I 6) Cetuplete the fulluwiug ergauic reactiuns with structures cf the pruducts. CH3 @ HBr(g) CH3 E) b. ( f 6) Cuusider the acid-base reactiun below: 0 O O O [ || 9 || || CH3CCHECC H3 + Cch H20 CH3CCHCCH3 + Cch HEOH I (4) Per the reactieu in the lefi re right directiun identify: the acid (A) the eeujugate acid (CA) the base (13) the ceujugate base (CE) I (2) The twu species en the right are favered at equilibrium- Identify the struuger acid in this reactieu. Justify vuur chuice. 4 c. ( i 4) Censider the additien ef HBr te an alkyne. As shewn beiew the reactien preceeds in a stepwise fashien by way ef an niicenyi halide. The aikenyl halide then reacts with a seeend melecule ef HBr(g) te give the final preduet. H30; Br B H H+ . CHSCECCHg i4 9:0; ——- L CHECHECBrEGHa H CH3 alkeuyl halide catlenie Intermeeiate I (2) Determine the geemetry at the deuhle bend ef the alkenyl halide (circle ene). cis- E— trnns- Z- I (2) Write a structure fer the enrienie intermediate ef the secend step. d. { i 3) An article in this week‘s issue ef Chemicai dz Engineering News describes a new methed fer the synthesis ef secendary amines invelving additien te a terminal alkene. The general reacti en fermat is shewn beiew. tantalum eatal at Q ,CHg + HGH=CH2 ————y——P O H H H CH3 Use the funetienal appreach te deduce the structure ef the unsaturated reneieni in the eaan‘ipie belew. Q tantalu m catalyst ..- CH3 + ———————-— ' N ”W H H {3 H3 4. (l4 Peints) NOIVTENCLATURE AND UNSATURATED COWOUNDS a. '{~ I 6) Censider the unsaturated cempeund A (a diyne) helew which was used recently as a reactant in a study ef certain ting-ferniing reactiens [Org ten. 2007, 9, 1907]: _n. H2, cataiyst at; {:9 ————-— cempeund A I (3) Assign the IUPAC name te cempeund A. HINT: The name ef the CH alkane is undecane. I (3) Cemetete the reactien ef cernpennd A with a structure fer the preduct. Yen may assume that the hydregen is in eacess. 5 b. t f 3, BONUS QUESTION!) Cumplete ONE cf the fullcwing questicns. If ycu answer bcth ycu will get credit fer the cue best answer. -Write a jagged line fnrmula fur 2,9-dimethy1deca-l ,Q—diene- 4,6—diyne [Org Lett. 20137, 9, 1851]. rPrcyide the IUPAC name fur the unsaturated tetraene belcw. ! a “s. CH3 ”I eta c ( I 5) Ccnsider the unsaturated cumpcund belcw, a marine natural prcduct recently studied by chemists at the University cf Califcrnia, San Diegn [Org Lett, 2007, 9, 1975]. ccsH I (3) Directly en the structure lccate all dcuble beads with the (Ejecnflguraticn. n (2) Write in all cliylic hydmgens and label them as Ha. d. ( r“ 3) The ccmpcund belcw has been utilized as a reactant by Japanese chemists in a synthetic rcute tc elaiclide, a pctent antibictic against Gram-pcsitiye bacteria [Tetrahedrcn Lett. 2007, 48, 3163]. Directly en the structural furmula lccate all bunds abcut which there is free rc-tatiun. Tc help yuu get started, cne such bund has already been lccated. 5. (14 Pcints) MULTIPLE CHOICE. Write the letter cf the must currect respcnse in the space prcyided tn the left cf the questiun. Vinylacetylene is an industrial chemical used in the synthesis cf neuprene. The structure cf yinylacetylene is shcwn tn the right. Which cf the fullcwing is an accurate descripticn cf the structure cf yinylacetylene? A. One acetylenic hydrugen, cne prcpargylic hydrcgen, twc yinylic hydrugens. B. One acetylenic hydrcgen, cne allylic hydrcgen, twc yinylic hydrngens. C. One acetylenic hydrngen, three yinylic hydrcgens. D. One prcpargylic hydrogen, three yinylic hydrcgens. 6 Which bf the cbmpbunds belbw Vifllfltflfl Eredt's rule? Estimate the barrier tb rbtatibn abbut the C(3)—C(4) bbnd bf H-hEXflflE. A. 5 kCflUmUIE B. 15 kcaL’mble C. 65 kcab’mble D. 90 kcalt'mble Which bf the fbllbwing terms best describes an alkynyl (acetylide) anibn‘? A. Weak base B. Cbnjngate base bf a very weak acid. C. Cbnjugate base bf a strbng acid D. Weak acid Determine the dihedral angle between the twe methyl grbups in the anti cbnfbrmatibn bf butane? A. 0'3 B. 60'” C. 120‘" D. 180” Which bf the fbtlbwing cbmpbnnds is capabte bf gebmetric isbmerism? cH;J {EH3 A. O B. CHsGHQCECCHECHa C. GH3GH2cH=c: D. CH30H36=CHCHECH3 cHa What is the cbmmbn name bf the branched alkyl grbtip tb the right? C(CH ) '— 3 s A. tertFBntyl B. Nebbntyl C. Isbbutyl D. Trimethylmethyl ...
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