THIRD Name HOUR TEST
KEY
1. (21, 7 each) In the spaces provided below, give the correct IUPAC names for the compounds having each of the following structures.
a. 7-chloro-3-cyano-5-cyclopentyl-2-ethoxy-6-oxohept-3-enoyl chloride
b. 5-amino-N-cyclohexyl-6-propoxy-N-propylcyclohepta-2,5-dienecarboxamide
c. 1-ethyl-4-mercaptobut-2-ynyl 4-ethyl-6-hydroxyhex-4-enoate
2.(6) Pravachol , for which the structure is shown to the right, is one of the LDL (or "bad") cholesterol lowering drugs known as "statins." The final step in its synthesis, shown in simplified form below , is reaction of NaOH with a lactone to give the dihydroxycarboxylate product shown. Write the steps in the mechanism that accounts for opening the lactone under the conditions shown. REMEMBER: You may not add any other reagents. Be sure to show: (1) all intermediate structures that occur in the course of the mechanism, (2) any resonance structures that play a role in the process, (3) what, if anything, is added or lost at each step, and (4) all formal charges on the structures that you draw.
Third Hour Test (b), Chemistry 302, Fall 2004, Page 1 of 7 pages
3. (21) When synthesizing peptides, which are similar to proteins but contain fewer amino acids, one of the common first step is to convert the carboxylic acid of an amino acid into a benzyl ester which can subsequently be removed by hydrogenolysis when required by the synthesis. Below is shown preparation of the benzyl ester of alanine hydrochloride prior to its introduction into a peptide. Write the steps in the mechanism that accounts for the indicated reaction under the conditions shown. REMEMBER: You may not add any other reagents. Be sure to show: (1) all intermediate structures that occur in the course of the mechanism, (2) any resonance structures that play a role in the process, (3) what, if anything, is added or lost at each step, and (4) all formal charges on the structures that you draw.
Third Hour Test (b), Chemistry 302, Fall 2004, Page 2 of 7 pages
4. (14) Starting with methyl cyclopentanecarboxylate and 4-methyl-1-pentene as the only sources of carbon atoms for the final product, show how to synthesize cyclopentylmethyl 3-methylbutanoate. You may use any other needed reagents or solvents so long as they do not contribute carbon atoms to the product. The reactions you use in each step should give the product you want as the major product of the reaction. It is NOT NECESSARY to show the mechanisms of the reactions you use. Including hydrolysis steps, pH adjustments, etc., about 5-6 steps are required. REMEMBER: If you want to add two sets of reagents in succession, you should number the steps. If the steps are not numbered, it indicates that you are adding the chemicals simultaneously. A table of reagents you have learned about in your study of organic chemistry is provided at the end of the test.
Third Hour Test (b), Chemistry 302, Fall 2004, Page 3 of 7 pages
5.(12) Many compounds containing one or two carbon atoms, often at a high oxidation state, are considered inorganic chemicals. Examples include CO, CO2, CaCO3 , NaHCO3 , K2 CO3 , HCN, KCN, and CaC2 (the calcium carbide used to make acetylene in miners' lamps). Many of these inorganic chemicals are useful for making carboxylic acids. DEET, or N,N-diethyl-meta-toluamide, is a widely used insect repellent. Show how DEET can be synthesized starting with meta-bromotoluene, diethylamine, and any needed inorganic chemical sources of carbon atoms. You may also use any other needed reagents or solvents. Including hydrolysis steps, etc., about 5 steps are required. The reactions you use in each step should give the product you want as the major product of the reaction. It is NOT NECESSARY to show the mechanisms of the reactions you use. REMEMBER: If you want to add two sets of reagents in succession, you should number the steps. If the steps are not numbered, it indicates that you are adding the chemicals simultaneously. A table of reagents you have learned about in your study of organic chemistry is provided at the end of the test.
Third Hour Test (b), Chemistry 302, Fall 2004, Page 4 of 7 pages
6. (12) The amino acid lysine has the pKa's for the carboxylic acid and ammonium groups indicated on the structure to the right.
a. (4) Using the Henderson-Hasselbalch equation, determine at what pH the ratio of carboxylate to carboxylic acid will be 1000 : 1. SHOW YOUR WORK.
b. (3) Using the Henderson-Hasselbalch equation, determine the ratio of ammonium ion to free amine for the ammonium ion having pKa = 9.2 at the pH you found in part a. SHOW YOUR WORK. (If you were unable to answer part a of this problem, use pH 7.2.)
c. (2) Using the Henderson-Hasselbalch equation, determine the ratio of free amine to ammonium for ion the ammonium salt having pKa = 10.2 at the pH you found in part a. (If you were unable to answer part a of this problem, use pH 7.2.)
d. (3) Draw the structure that best represents the protonation states and formal charges on most molecules of this amino acid at the pH you calculated in part a. (If you were unable to answer part a of this problem, use pH 7.2.)
Third Hour Test (b), Chemistry 302, Fall 2004, Page 5 of 7 pages
7. (14) The Dieckmann condensation is a variation of the Claisen condensation that gives a cyclic b-keto ester as the product. The Dieckmann condensation of dimethyl heptanedioate using sodium methoxide (followed by acidification of the reaction mixture) leads to formation of methyl 2-oxocyclohexanecarboxylate. Write the steps in the mechanism that accounts for formation of the indicated product. REMEMBER: You may not add any other reagents. Be sure to show: (1) all intermediate structures that occur in the course of the mechanism, (2) any resonance structures that play a role in the process, (3) what, if anything, is added or lost at each step, and (4) all formal charges on the structures that you draw.
Third Hour Test (b), Chemistry 302, Fall 2004, Page 6 of 7 pages
Reagents and Conditions
A. Ha logen-introducing R eagents Cl2 / H 2O Cl2 / CH 3OH Cl2 / CH 2Cl2 Cl2 / hn Cl2 / FeCl3 HCl / ether / 25 oC HCl / CH 3COOH / NH 4Cl HCl (conc) / 0 oC HC l / H 2O SOCl2 (thionyl chloride)/pyridine SOCl2 / CHCl3 SOCl2 / D SOCl2 / D / C 6H 6 Br 2 / H 2O Br 2 / CH 3OH Br 2 / CH 2Cl2 Br 2 / hn Br 2 / FeBr3 PBr3 / ether HBr / ether / 25 oC HBr / CH3COOH HBr (conc.) / 0 oC HB r (aq) / D K +Br - / DMSO KI / H 3PO 4 / 0 C HI (a q.) / D I 2 / H 2O I 2 / CH 3OH I 2 / CH 2Cl2 I 2 / CuCl2 P / I 2 [PI3] Na + I - / acetone B. Bases Na 2CO 3 [sodium carbonate] NaOH NaOH (aq) NaOH / H 2O / D Na + -HCO 3 Na + H Na + -NH 2 / NH 3 (liq.) KO H / D / CH 3CH 2OH CH 3O - Na + / CH 3OH CH 3O - Na + / toluene CH 3CH 2O - Na + / CH 3CH 2OH CH 3CH 2O - Na + / toluene CH 3C(O)O - Na + [sodium acetate] CH 3CH 2CH 2CH 2- Li+ [butyllithium or B uLi] C 5H 5N [pyridine] C. Acids H 2SO 4 / D H 3PO 4 / D H 2SO 4 / H 2O [H 3O +] H 2SO 4 / H 2O / D H 2SO 4 / D / H 2O removal H 2O / H 2SO 4 / THF HBF 4 / H 2O HNO 3 (conc.) / H 2SO 4 (conc.) H 2SO 4 / SO 3 [fuming sulfuric acid] AlBr 3 AlCl3 CF 3C(O)OH D. Bo ron, Sulfur, and Ph osphorou scontaining Rea gents BH 3 / THF NaBH 4 / H 2O (C 6H 5) 3P: [Ph 3P:] POCl 3 / pyridine CH 3SO 2Cl / pyridine CH 3C 6H 4SO 2Cl / pyridine E. Mercury and Copper-containing Reagen ts Hg(OC(O)CH 3) 2 / H 2O [mercuric acetate] H 2O / H 2SO 4 / HgSO 4 Hg(OC(O)CH 3) 2 [mercuric acetate] Hg(OC(O)CF 3) 2 [mercuric trifluoroacetate] Cu 2Cl2 [CuC l] Cu 2Br 2 [CuBr] CuI CuC /N Na + NO 2- / Cu F. Cyanide and Acetylide Nucleophiles K + -C /N / DMSO H-C /N / K + -C /N (cat. amt.) H-C /C - Na + CH 3-C /C - Na + G. Carbon Electrophiles [CH 3C(O)] 2O [acetic anhydride] / pyridine H 2C=O -CH 2-O-CH 2- [ethylene epoxide] CO 2 [Dry Ice o r gas] CH 3-I / Ag2O H. Nitrogen and Sulfur Nucleophiles NH 3 (liq) / D (sealed tube) Na + -N=N =N [sodium azide] NH 2OH [hydroxylamine] NH 2NH 2 / ph 5 [hydrazine] NH 2NHC 6H 5 / pH 5 NH 2NHC 6H 3(NO 2) 2 / pH 5 CH 3S - Na + HS - Na + I. Protecting / Deprotecting R eagents HOCH 2CH 2OH / H 2SO 4 / D / water removal (CH 3) 3Si-Cl / (CH 3CH 2) 3N: (or pyridine) (CH 3CH 2CH 2CH 2) 4N + F - / HF (aq.) J. Oxidizing Ag ents C 6H 5C(O)-O-O -C(O)C 6H 5 (benzoyl peroxide) H 2O 2 (aq) / CH 3COOH H 2O 2 (aq) / Na + OH H 2O 2 (aq) / pH 8 buffer O 3 / -75 C / CH 2Cl2 OsO 4 OsO 4 / H 2O 2 (aq) Na 2Cr 2O 7 / H 2SO 4 / H 2O / acetone [Jo nes' reagent] CrO 3 / H 2SO 4 / H 2O /acetone [alternate Jones' reagent] C 5H 5N +-H CrO 3Cl- [PCC] / CH 2Cl2 Ag 2O / NH 4OH [To llens' reag ent] KM nO 4 / H 2O / D KM nO 4 / H 2O / NaOH / cold Na + NO 2- / H 2O / HX / 0 C HIO 4 or H 5IO 6 m-ClC 6H 4C(O)O OH [m-CPB A] CH 2Cl2 K. Red ucing Ag ents H 2 / PtO 2 / alcohol H 2 / Pd/C / alcohol H 2 / Pd/CaCO 3 / Pb(OAc) 2 quinoline (Lindlar's cat.) H 2 / Pd/C / alcohol / H + H 2 / Rh/C / alcohol NaBH 4 / H 2O / alcohol LiAlH 4 / ether LiHAl[OC(CH 3) 3] 3 / ether H-Al[CH 2CH(CH 3) 2] 2 [DiBAL-H] toluene / -75 C NaHSO 3 (aq) H 3PO 2 SnCl2 / HCl (aq) Na / NH 3(liq) Li / NH 3 (liq.) Fe / H Cl (aq .) Zn / CH 3CO OH (aq.) Zn(H g) / HC l (conc .) / D NH 2NH 2 / NaOH / DMSO L. M etals Mg / ether Li / pentane Na Cu M . Solvents NH 3(liq) (liquid ammonia) H 2O CH 3CH 2OCH 2CH 3 (ether) -CH 2CH 2OCH 2CH 2- (THF) CH 3OH (methyl alcohol) CH 3CH 2OH (ethyl alco hol) CH 3C(O)OH (acetic acid) HC(O)OH (formic acid) CH 3S(O)CH3 (DMSO) HC(O)N(CH3) 2 (DMF) CH 3C(O)CH 3 (acetone) CH 3C /N (acetonitrile) CH 2Cl2 (dichloromethane) C 6H 6 (benzene) C 6H 5CH 3 (toluene)
Second Hour Test, Chemistry 302, Fall 2004, Page 7 of 7 pages