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Departmental Final Examination
Organic Chemistry I
2423
Caffein
Name
Name ___________________________________________
CHEMISTRY 2423 FINAL EXAM
FALL, 2005
DIRECTIONS: A periodic table is attached at the end of this exam. Please answer all
questions as completely and clearly as possible, showing all your work.
Part I. Nomenclature and Structures (2 pts each)
1. Give the correct IUPAC name for the following structures (2 pts each):
CH3 - CH2 - C - CH2 - CH - CH3
CH3
CH2
Br
(c)
(b)
(a)
(a) _____________________________________
(b) _____________________________________
(c) _____________________________________
2. Draw the structure that corresponds to the following name (2 pts each):
(a) (R)- 3-bromohexane
(b) Trans-3– chloro–4-methyl-cyclpentene
(c) 4,5-diethyl-2- heptyne
Part II. Multiple choice. Circle the one best answer. (2 pts each)
3. For the molecule, shown, what are the hybridization of the oxygen atom and the approximate C-C-O bond
angle, respectively?
CH3CH2CCH2C
CH
O
3
A. sp , 109.5
3
C. sp2, 120
B. sp , 120
2
D. sp2, 180
4. What functional group is present in the molecule shown?
O
A. alcohol
B. ester
C. amide
D. ether
5. The most stable conformation of cis-2-tert-butylcyclohexanol is a chair with the OH group:
A. equatorial and tert-butyl group equatorial
C. equatorial and the tert -butyl group axial
B. axial and the tert -butyl group axial
D.axial and the tert -butyl group equatorial
6. What are the configurations of carbons 1 and 2 in the compound , 2-methylcyclohexanol, shown below?
2
1
H
H
H3C
A. 1R, 2S
OH
B. 1S, 2R
C. 1R, 2R
D. 1S, 2S
7. What is the conjugate Acid for CH3O-?
(A) CH3O-
(B) CH2OH-
(D) CH3OH2+
(C) CH3OH
8. Which of the following alkyl halides gives only one alkene as the product in the elimination reaction?
Br
Br
Br
CH2CCH3
CH3
CH3CH2CCH3
CH3
CH3
B
A
Br
D
C
9. Which one of the following groups has the highest priority?
- COOCH3
-OOCH3
(A)
(B)
-COCH2CH3
(C)
3
-OCOCH2CH3
(D)
10. Which of the following is the best synthesis of cyclohexene from cyclohexane?
A. KOH, alcohol
C. Br2, light; then KOH, alcohol
B. H2SO4
D. Br2, light; then H2SO4, heat
11. Which of the following is the most stable conformation of 1,3-dimethylcyclohexane?
CH3
CH3
CH3
H3C
CH3
CH3
CH3
A.
CH3
B.
C.
D.
12. What is the major organic product of the following reaction?
CH3C
CCH3 + Li
liquid NH3
H3C
-
H3CC
+
C Na
CCH2-Na+
H3CC
CH3
C
C
H
A
H
C
H
B
H3C
H
CH3
C
D
13. Which of the statements about the molecule shown is TRUE?
_
N
O
_
A. The geometry of N is trigonal planar.
C. The hybridization of N is sp2.
B. The formal charge on O is -1.
D. The formal charge on the N is +1.
14. Which of the following free radicals is the MOST stable?
.
A.
B.
15. What is the IUPAC name for the molecule shown?
C.
4
C
D.
Cl
A. cis-1,2-diethyl-1-chloro-2-methylene
C. (E)-1-chloro-1-ethyl-1-pentene
B. (E)-3-chloro-4-methyl-3-hexene
D. (Z)-1-chloro-1-ethyl-1-pentene
16. What is the degree of unsaturation in DDT, C14H9Cl5?
A. 5
B. 6
C. 7
D. 8
17. What is the direction of the dipole moment in the molecule shown?
H
H
C
Cl
H
A.
B.
C.
D.
18. Which of the following statements is true about the reaction shown?
CH2CH2Cl
H
C
OH-
Br
CH3
A. The product will have R configuration.
C. The product will have S configuration.
B. A meso compound is produced.
D. The reaction will happen with recemization.
19. Which of the following compounds has the HIGHEST boiling point?
A
B
C
D
20. Which of the step(s) of a free radical chain reaction is deactivation step with an activation energy equal to
zero?
A. initiation only B. propagation only C. termination only
D. both termination and initiation
21. Molecule A is the enantiomer of molecule B. Molecule B is a stereoisomer of the molecule C but NOT its
5
mirror image. What is the relationship between A and C?
A. Same compound.
C. Diastereomers
B . Enantiomers.
D. Constitutional isomers
22. Which of the following statements about the relative stabilities of the structures shown is TRUE?
A II is more stable than I
C. I is more stable that II
B. II represents a gauch conformation.
D. Two of these are true
23. The following process demonstrates:
OH
(A) resonance
(B) conjugation
O
(C) racemization
(D) tautomerism
24. Which of the following will give the transformation shown?
H
+?
OH
A. Cl2, H2O
C. Hg(OAc)2/H2SO4, water
B. PBr3 followed by H3O+
D. BH3, THF followed by H2O2, OH-
25. In mass spectroscopy,
(A)
(B)
(C)
(D)
the sample is irradiated with infrared radiation
the heat of combustion of the sample is measured
the sample is bombarded with a stream of high energy electrons
the sample is irradiated with ultraviolet radiation
26. Which of the following fragment shows a peak at m/e = 29 in the mass spectrum.
(A) CH3CH2+
Part III. Reactions
(B) CH3CH2•
(D) (CH3)2CH+
6
D. all of these
Give the major product(s) of each of the following reactions. Show all relevant stereochemistry. (2 pts
each)
27.
H2SO4
(H3C)2CCH2CH3
heat
OH
28.
CH3C
2 mol HBr
CH
29.
C
C
H
HgSO4, H2O
H2SO4
30.
Br2
CCl4
31.
HBr
CH-CH3
ether
CH3
32.
H2O
+ Br2
33.
(CH3)2C = CHCH3
1) BH3, THF
2) H2O2, OH-
34.
1) O3
2) Zn/H3O
35.
CH2 I2 / Zn(Cu)
36.
KMnO4
H3 O+
7
Part IV. Synthesis ( 3 points each)
Show by a series of reactions how you could prepare the following compounds (major) from the indicated
starting compound. Be sure to clearly indicate the reagent used in each step.
37.
OH
38.
39.
O
Acetylene
CH3 - C - CH2 - CH2 - CH3
8
Part V. Mechanisms
Write a complete mechanism for the following reactions. Show all intermediate structures, formal
charges, and electron flow using the curved arrow convention.
(3 pts each)
40.
CH3
CH3
OH
Br2 / H2O
Br
41.
OH
H2SO4
heat
9
Part VI. Spectra ( 5 points)
Use the mass spectrum for a cyclicalkene shown below to answer questions 42 - 44.
42. What is the base peak (1 pt)?
43. What is the parent ion peak (1 pt)?
44. What is the structure of the compound (3 pts)?
10
ORGANIC CHEM 2423 FINAL EXAM (FALL 2005) Answers
PART I – Nomenclature and structures (2 points each)
1.
(a) 3-isobutyl-1-methylcyclohexene
(b) 3-bromo-4-methyl-1-pentyne
(c) 2-ethyl-4-methyl-1-pentene
2.
Cl
CH2CH2CH3
a)
CH2CH3
CH3
c) CH3C
b)
C - CH - CH - CH2 - CH3
H
Br
CH2CH3
CH2CH3
PART II – Multiple Choice (2 points each)
3. C
10. C
17. C
24. D
4. D
11. A
18. C
25. C
5. D
12. D
19. A
26. A
6. A
13. D
20. C
7. C
14. B
21. C
8. B
15. B
22.D
9. B
16. D
23. D
PART III. Reactions (2 points each)
H
H
27.
H
C=C
CH3
Br
28.
CH3
O
29.
C - CH3
30.
Br
CH3
Br
OH CH
3
Br
O
CH-CH3 32.
Br
H
CH3
35.
O
34.
33.
31.
Br
OH
36.
O
+ CO2
CH3
CH3
PART IV. Synthesis (3 points each)
37.
38.
OH
H2SO4
heat
CH2I2
Zn(Cu)
H2SO4
H2 O
11
OH
H2SO4
heat
O
39.
CH3 - C - CH2 - CH2 - CH3
Acetylene
HgSO4/H2O
NaNH2
H-C
C :-
H2SO4
Na+
CH3CH2CH2Br
H-C
C - CH2CH2CH3
Part V. Mechanisms (2 pts each)
40.
+
CH3
CH3
Br
CH3
+
Br - Br
OH2
:OH2
Br
CH3
OH
CH3
H
Br
:Br-
H
Br
OH2
CH3 O
Br
41. OH
+
OH2
H
H - OHSO3
OHSO3
Part VI. Spectra (5 points)
42. base peak , m/e =67
43. parent peak , m/e = 82
43. Structure: 4-Methyl-1-cyclopenten
CH3
12
+ H2SO4