THE UNIVERSITY OF CALGARY FACULTY OF SCIENCE FINAL EXAMINATION CHEMISTRY 350

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1 Page 1 of 16 TE UNIVERSITY F CALGARY FACULTY F SCIENCE FINAL EXAMINATIN CEMISTRY 350 April, 1997 Time: 3 ours PLEASE WRITE YUR NAME, STUDENT I.D. NUMBER AND SECTIN NUMBER (01 for MWF lectures and 02 for TR lectures) N BT YUR EXAM BKLET AND CMPUTER ANSWER SEET. Read the instructions carefully. The examination consists of Parts 1-10, each of which should be attempted. Note that some Parts provide you with a choice of questions. Parts 1-6 will be computer graded, and only Parts 7, 8, 9 and 10 are to be answered in your examination booklet. A periodic table with atomic numbers and atomic weights, and tables of spectroscopic data are appended to the end of the exam. Parts 1-6 consist of a series of multiple choice questions numbered 1-43 which are to be answered on your computer answer sheet. Indicate your answer by blackening out the appropriate space, A, B, C, D or E on the answer sheet. Use a pencil only and not ink. In some cases it is required that you indicate multiple items for a complete and/or correct answer by blackening out more than one space. In some other cases more than five options are available and some of these also require more than one space to be blackened out. For an example, an option specified as AB requires that you blacken out both space A and space B. Part marks may be awarded in some of the questions. Incorrect answers must be erased cleanly. Molecular models are permitted during the exam; calculators are also permitted, but NT programmable calculators.

2 Chem 350 Cont'd Page 2 of PART 1 RELATIVE PRPERTIES Do ANY SEVEN (7) of Questions Arrange the items in Questions 1-10 in DECREASING RDER (i.e. greatest, most etc. first) with respect to the indicated property. Use the following code to indicate your answers. A. i > ii > iii D. ii > iii > i B. i > iii > ii E. iii > i> ii C. ii > i > iii AB. iii > ii > i 1. The acidity of the protons C 2 C C 2 C C 2 C-C 2 CC 2 2. Rate of reaction of 2 /Fe 3 with: N 2 Cl 3. Reactivity towards hydrolysis using 2 of: C CN 2 CCl

3 Chem 350 Cont'd Page 3 of Reactivity towards the addition of 1 equivalent MeMg to: 5. The IR stretching frequency of the CN bond in: C N C N 2 C N 6. The multiplicity of the peaks for the Me group in the NMR for each of the following fragments: ÄC 2 ÄC( ) 2 ÄC( ) 3 7. The % of conjugate addition product from the reaction of MeMg with: C CC C CC C 2 CCC( ) 3 8. The % of the para product produced in the reaction of N 3 / 2 S 4 with: C( ) 2 C( ) 3

4 Chem 350 Cont'd Page 4 of The number of enolizable protons in: C 10. The % of the conjugate addition product for reaction of C 2 CC with: Li Mg ( ) 2 CuLi

5 Chem 350 Cont'd Page 5 of PART 2 MECANISMS Do ANY FIVE (5) of the Qestions Choose the mechanistic term from the list provided below that best describes the reaction shown: 11. KMn 4 -, o C 12. hν 13. C 2 racemic C 2 A. S N 1 B. S N 2 C. E1 D. E2 E. Syn elimination AB. Syn addition AC. AD. AE. BC. BD. BE. Anti addition Conjugate addition Markovnikov addition Anti-Markovnikov addition Electrophilic aromatic substitution Nucleophilic aromatic substitution

6 Chem 350 Cont'd Page 6 of N 2 N 3 cat. 2 S CN KCN DMS 16. Ph Cl NaEt Et Ph only A. S N 1 B. S N 2 C. E1 D. E2 E. Syn elimination AB. Syn addition AC. AD. AE. BC. BD. BE. Anti addition Conjugate addition Markovnikov addition Anti-Markovnikov addition Electrophilic aromatic substitution Nucleophilic aromatic substitution

7 Chem 350 Cont'd Page 7 of 16 6 PART 3 LABRATRY Do ANY SIX (6) of Questions For each question 17-24, various statements about laboratory techniques, reactions or materials are made. If the statement is TRUE, blacken A, if it is FALSE then blacken B. 17. Nylon-6,6, prepared by reacting adipoyl chloride with hexamethylene diamine is an example of a condensation polymer. 18. Diethyl malonate, when treated with sodium ethoxide, generates a nucleophilic intermediate called an enolate. 19. In the barbiturate synthesis, potassium iodide is employed as a base. 20. Soap can be prepared by the hydrolysis of triglyceride esters ,4-Dinitrophenylhydrazione (2,4-DNP) can be used to test for the presence of all the following functional groups: Aldehydes, ketones, acids, esters and alcohols. 22. The yellow colour of a positive iodoform test is due to the precipitation of CI A saturated fat can be prepared by the hydrogenation of an unsaturated oil in order to produce a harder solid fat. 24. The purpose of a reflux condenser set-up is to allow an equilibrium reaction mixture to be driven to completion by removing a volatile component.

8 Chem 350 Cont'd Page 8 of PART 4 PRDUCTS F SYNTESIS For ANY FIVE (5) of Questions 25-30, identify the product from each reaction ) LDA / TF 2) C 3) DMS, oxalyl chloride Et 3 N, C 2 Cl 2, -78 o C 26. Me 1) Cl, AlCl 3 2) KMn 4 + 3) Me,, Me C 2 Me C Me C Me Me Me

9 Chem 350 Cont'd Page 9 of Me 1) PhSeCl, Pyridine 2) 2 2 Me PhSe Me Me Me SePh 28. Me 1) NaB 4 / Me 2) Na / TF then MeI 3) DIBAl + - 4) Ph 3 P C 2 Me Me

10 Chem 350 Cont'd Page 10 of ) S S, + 2) P 3 3) Mg / ether 4) then 3 + S S S S S S 30. 1), 2) 3 then Zn / C 2 3) excess LiAl 4

11 Chem 350 Cont'd Page 11 of PART 5 STARTING MATERIALS FR SYNTESIS Do ANY FIVE (5) of Questions In each case, choose the starting material from the selection provided that gives the product indicated via the transformations shown ) 2) LiAl 4 3) PCC, + 4) Mg then 3 + CN Me 32. 1) LDA / TF then MeI 2) LiAl 4 3) TsCl, Pyridine Ts TsCl = S Cl Me CN

12 Chem 350 Cont'd Page 12 of ) Cu 2) Mg/ether 3), then 3 + N 2 N 2 N 2 N N ) PCC + 2) Ph 3 P C - 2 3) B 3 then 2 2 /Na 4) DMS, oxalyl chloride Et 3 N, C 2 Cl 2, -78 o C Cl CN

13 Chem 350 Cont'd Page 13 of ) Mg/ether, then C 2 2) LiAl 4 3) TsCl, Pyridine 4) NaCN CN C ) LDA, TF -78 o C Cl 2) 3) MeLi then 3 +

14 Chem 350 Cont'd Page 14 of PART 6 Do ANY FIVE (5) of Questions From the list of reagents provided, select the reagent combination required for each numbered step. 37. N 38. C 2 Et 39. C C 2 Et A. 1 eq LiAl 4 then 3 + B. 1 eq NaB 4 /Me C. 1 eq DlBAl then 3 + D. excess Na 2 Cr 2 7 / 2 S 4 E. PCC AB. 3 / 2 2 AC. 3 /Zn/ 2 AD. 2 2 / AE. C 3 BC. Et/+ BD. NaMe/+ BE. N 2 4 /-/ CD. 2 / Raney Ni CE. SCl 2 DE. B 3 then 2 2 /Na

15 Chem 350 Cont'd Page 15 of PART 7 TTAL SYNTESIS: Using benzene, cyclopentadiene, propyne, and / or any starting material with two or less carbons, design an efficient synthesis for NE (1) from Part A AND NE (1) from part B. Do NT show mechanisms. Part A C 2 N 2 N 2 N 2 Part B N Me

16 Chem 350 Cont'd Page 16 of PART 8 SPECTRSCPY: Write your answer in the booklet provided. From the IR, MS, UV, C NMR and NMR data shown below, identify the unknown organic molecule. Indicate any partial structures that you are able to deduce from these spectra. Part marks will be awarded.

17 Chem 350 Cont'd Page 17 of PART 9 MECANISM: Write your answer in the booklet provided. Answer NE (1) question from Section A AND NE (1) question from Section B. 5 Section A Draw a detailed, stepwise mechanism (using only arrows following transformations occurs: ) to explain how one of the EITER C + C 2 C 2 + C + 2 R + 1) K 2) 5 Section B Using a short paragraph and / or diagrams (hint: resonance structures) (max. ½ page), account for the differences in the reaction sequences for NE of the following: EITER N 2 excess 2 N 2 1) CCl 2) excess 2 N 2 + 3) 3, R N 3 BUT N 3 N 2 N 2

18 Chem 350 Cont'd Page 18 of PART 10 STRUCTURE DETERMINATIN: Write your answer in the booklet provided. Compound A had an elemental analysis that showed % carbon and % hydrogen, and gave an orange precipitate when treated with 2,4-dinitrophenylhydrazone (2,4-DNP). When A was reacted with LiAl 4 in dry TF, B was produced and was found to react slowly under Lucas conditions (ZnCl 2 / Cl). When B was reacted with conc. 2 S 4 and heated, hydrocarbon C was produced. C gave a colourless solution when tested with 2 / CCl 3. Reaction of C with ozone followed by zinc in acetic acid work-up gave two compounds D and E which both reacted with 2,4-DNP. The NMR of A - E are shown to the right. What are A - E