CHEMISTRY 241 - EXAM #2
(100 points)
March 30, 2012
NAME ____________________________________
Show all work for full credit.
Try to answer every question. Chances are some answer is better than no answer.
Ask me questions if you are unclear about a question.
Do not cheat. It will result in a zero.
1. (6pts) Provide the proper IUPAC names for the following molecules. Assign stereochemistry only when
designated.
2. (10pts) The addition of HBr to 1-pentene could result in two possible products. Provide mechanisms for the
formation of both products and draw the reaction energy diagram for the addition reactions. On the reaction
energy diagram, be sure label the positions for all reactants, intermediates, and products in both cases.
Which product will be favored and why? Be sure to refer to you reaction energy diagram when explaining
your choice.
3. (20pts) Provide the necessary reagents to complete the following reaction sequence.
4. (6pts) Propose a mechanism for the following reaction.
5. (20pts) Draw all reactants or products for each of the following reactions based on the information
given.
a.
b.
(List all stereochemical products if necessary)
c.
(Do not account for stereochemistry chemistry)
d.
6. (9pts) Identify compounds A, B, and C.
a. Compound A has molecular formula C8H12 and reacts with two equivalents of H2. A gives
HCOCH2CH2CHO as the only product oxidative cleavage with O3 followed by Zn in acidic H2O.
b. Compound B has a molecular formula C6H10 and gives (CH3)2CHCH2CH2CH3 when treated with
excess H2 in the presence of Pd. B reacts with NaH2 and CH3I to form compound C (molecular
formula C7H12).
7. (8pts) Show the structure of the polymer of Plexiglass (poly methyl methacrylate), a polymer made from
the following subunit. Show at least three monomers linked together. Provide a mechanism for the
formation of this polymer that utilizes DBP as the initiator.
DBP
8. (10pts) A mixture of the two compounds below was dissolved in dichloromethane. Two TLC plates
were spotted with the mixture. One plate was developed using hexane (nonpolar) and one plate was
developed using ethanol (polar).
a. Identify the solvent used to develop each plate. Briefly explain.
b. Explain, in detail, how you would use 1H NMR to differentiate between compound A and
compound B.
Compound A
Compound B
Plate A
Plate B
A
B
A
B
c. A student in the lab has attempted to purify compound A by recrystallization. He has taken his
entire product and dissolved it in a large amount of boiling solvent. He walked away to make
notes and when he came back, all of the solvent was gone and he had recrystallized compound
A. Would you expect his compound A to be pure? Explain.
9. (11pts) Using any necessary inorganic reagents, show how you would convert acetylene and isobutyl
bromide to meso-2,7-dimethyloctane-4,5-diol.
Isobutyl bromide
possible useful reaction information
Bonus:
Name at least one team in the final four of the Men’s and one team in the Women’s final four for the
NCAA basketball tournaments?
Write an electron configuration for your favorite element (not hydrogen)!
IA
1
H
1.008
3
Li
6.941
11
Na
22.99
19
K
39.10
37
Rb
85.47
55
Cs
132.9
87
Fr
(223)
IIIB
21
Sc
44.96
39
Y
88.91
57
La
138.9
89
Ac
(227)
IIA
4
Be
9.012
12
Mg
24.31
20
Ca
40.08
38
Sr
87.62
56
Ba
137.3
88
Ra
(226)
22
Ti
47.87
40
Zr
91.22
72
Hf
178.5
104
Rf
(261)
IVB
24
Cr
52.00
42
Mo
95.94
74
W
183.8
106
Sg
(266)
59
Pr
141
91
Pa
231
58
Ce
140
90
Th
232
VIB
23
V
50.94
41
Nb
92.91
73
Ta
180.9
105
Db
(262)
VB
60
Nd
144
92
U
238
25
Mn
54.94
43
Tc
(98)
75
Re
186.2
107
Bh
(264)
VIIB
61
Pm
(145)
93
Np
(237)
26
Fe
55.85
44
Ru
101.1
76
Os
190.2
108
Hs
(265)
62
Sm
150
94
Pu
(244)
27
Co
58.93
45
Rh
102.9
77
Ir
192.2
109
Mt
(268)
VIIIB
63
Eu
152
95
Am
(243)
28
Ni
58.69
46
Pd
106.4
78
Pt
195.1
110
Ds
(269)
64
Gd
157
96
Cm
(247)
29
Cu
63.55
47
Ag
107.9
79
Au
197.0
111
-(272)
IB
65
Tb
159
97
Bk
(247)
30
Zn
65.39
48
Cd
112.4
80
Hg
200.6
112
-(277)
IIB
66
Dy
163
98
Cf
(251)
5
B
10.81
13
Al
26.98
31
Ga
69.72
49
In
114.8
81
T1
204.4
IIIA
67
Ho
165
99
Es
(252)
6
C
12.01
14
Si
28.09
32
Ge
72.61
50
Sn
118.7
82
Pb
207.2
114
-(285)
IVA
68
Er
167
100
Fm
(257)
7
N
14.01
15
P
30.97
33
As
74.92
51
Sb
121.8
83
Bi
209.0
VA
69
Tm
169
101
Md
(258)
8
O
16.00
16
S
32.07
34
Se
78.96
52
Te
127.6
84
Po
(209)
116
-(289)
VIA
70
Yb
173
102
No
(259)
9
F
19.00
17
Cl
35.45
35
Br
79.90
53
I
126.9
85
At
(210)
VIIA
71
Lu
175
103
Lr
(262)
O
2
He
4.003
10
Ne
20.18
18
Ar
39.95
36
Kr
83.80
54
Xe
131.3
86
Rn
(222)
1
H NMR
13
C NMR
A Simplified Infrared Correlation Chart
Type of Vibration
C-H
Alkanes
Frequency (cm-1)
Intensity
(stretch)
3000-2850
-CH3
(bend)
1450 and 1375
m
-CH2-
(bend)
1465
m
Alkenes
(stretch)
3100-3000
m
(out-of-plane bend)
1000-650
s
(stretch)
3150-3050
s
(out-of-plane bend)
900-690
s
(stretch)
~3300
s
2900-2800
w
2800-2700
w
Aromatics
Alkyne
Aldehyde
s
C-C
Alkane
C=C
Alkene
1680-1600
m-w
not interpretatively useful
Aromatic
1600 and 1475
m-w
C≡C
Alkyne
2250-2100
m-w
C=O
Aldehyde
1740-1720
s
Ketone
1725-1705
s
Carboxylic Acid
1725-1700
s
Ester
1750-1730
s
Amide
1670-1640
s
Anhydride
1810 and 1760
s
Acid Chloride
1800
s
C-O
Alcohols, Ethers, Esters, Carboxylic Acids, Anhydrides
1300-1000
s
O-H
Alcohols, Phenols
Free
3650-3600
m
H-bonded
3500-3200
m
3400-2400
m
(stretch)
3500-3100
m
(bend)
1640-1550
m-s
1350-1000
m-s
Carboxylic Acids
N-H
Primary and Secondary Amines and Amides
C-N
Amines
C=N
Imines and Oximes
1690-1640
w-s
C≡N
Nitriles
2260-2240
m
X=C=Y
Allenes, Ketenes, Isocyanates, Isothiocyanates
2270-1950
m-s
N=O
Nitro (R-NO2)
1550 and 1350
s
S-H
Mercaptans
2550
w
S=O
Sulfoxides
1050
s
Sulfones, Sulfonyl Chlorides, Sulfates, Sulfonamides
1375-1300 and
1200-1140
s
s
C-X
Fluoride
1400-1000
s
Chloride
800-600
s
Bromide, Iodide
<667
s