Chemistry 220b, Section 1
Name ______________________________
Exam 2 (100 pts)
Thursday, February 26, 2015
Chapters 13, 15-19
Write and sign the VU Honor Pledge:
I pledge on my honor that I have neither given nor
received unauthorized aid on this examination
I. M. Honest
_____________________________________
signature
This exam is closed book and closed notes
NOTE: It is difficult for me to give you partial credit if you do not show your work!
Neatness counts
Stereochemistry counts are indicated
Good Luck !!
page 2 of 8
1 – 15. Multiple Choice. Choose the best answer for each of the following questions. (60 pts)
1. Which structure is most consistent with the following 1H NMR spectrum?
a)
b)
O
c)
O
H
d)
O
O
OH
OH
O
H
2. Which structure is most consistent with the following IR spectrum?
a)
b)
O
c)
O
H
d)
O
O
OCH3
N
3. What is the product of the following reaction?
O
+
a)
b)
HN
H
N
H
N
NH 2
H+
c)
d)
N
N
page 3 of 8
4. What is the product of the following reaction?
O
+
O
a)
NH 2
b)
N
c)
d)
NH
OH
O
OH
O
O
N
H
OH
N
5. What is the product of the following reaction?
O
H 3C-MgBr
(excess)
OCH2CH 3
then H 3O+
a)
b)
c)
O
d)
OCH2CH 3
OH
OCH2CH 3
OH
6. What is the product from the following reaction?
O
O
O
+
OH
NaHCO 3
Cl
a)
b)
O
c)
O
O
d)
O O
OH
O
7. What is the product from the following reaction?
O
+
OH
a)
O
b)
OH
O
O
H+
OH
c)
d)
O
O
O
8. What is the best reagent for the following reaction?
O
a) H 2NNH 2, KOH, H 2O
b) LiAlH 4, THF,
then H 3O+
c) H 2, Pd/C
d)
HO
OH
, H+
O
O
OH
page 4 of 8
9. Which combination of reactants will give (E)-3-methyl-3-hexene as the product?
O
a)
O
b)
+
+
Ph 3P
+
+
Ph 3P
(2 equivalents)
c)
+
Ph 3P
+
Br
d) all of the above; i.e., a, b, and c will all afford (E)-3-methyl-3-hexene
10. What is the best reagent for the conversion of a primary amide to a nitrile?
O
C
NH 2
b) H3O+, heat
a) P4O10, heat
N
d) NaCN, then H3O+
c) H2, Pd/C
11. Which reaction or reaction sequence does not affords phenylacetic acid?
OH
H 3O+
– CN
Br
a)
O
b)
Cr 2O7-2
+N
H
OH
OH
2
CH2Cl2
c)
O
Mg(0), THF
Br
OH
H 3O+
CO2
O
d) none of the above; i.e., a, b, and c are all afford phenylacetic acid
12. What is the order of reactivity, from most reactive to least reactive, for the following reaction?
O
H 3C
X
+ H 3C
N
H
O
CH 3
H 3C
+
N
H–X
X= OH, Cl, O2CCH 3, OCH3
O
a)
b)
c)
O
O
>
H 3C
OH
H 3C
O
>
Cl
H 3C
Cl
H 3C
O
OCH3
O
H 3C
O
O
H 3C
CH 3
O
OCH3
H 3C
O
Cl
OH
O
>
H 3C
OH
>
O
CH 3
H 3C
CH 3
O
>
H 3C
O
O
O
O
d)
O
O
>
H 3C
OCH3
>
>
Cl
H 3C
CH 3
>
O
H 3C
O
O
>
H 3C
O
O
>
>
H 3C
OCH3
H 3C
OH
page 5 of 8
13. Arrange the following carboxylic acids from the highest pKa value to lowest pKa value.
O
O
a)
>
OH
OH
O
O
>
F
>
OH
OH
F
O
O
b)
>
OH
OH
O
O
>
F
>
OH
OH
F
O
c)
O
>
OH
F
O
>
O
>
OH
OH
OH
F
O
d)
F
O
>
OH
OH
O
O
>
>
OH
OH
F
14. Which structure is an intermediate in the saponification of an ester?
O
OCH3
a)
HO
O
+ NaOH
b)
+
OCH3
O
c)
HO
OCH3
+OH
H
–
+ H 3COH
Na +
–O
d)
OCH3
OH
–O H
OCH3
+
OH
15. Which structure is not an intermediate in the formation of a ketal?
O
+
a)
H
HO + O
O–
HO
b)
OH
+ H
O
H+
O
O
+
c)
HO
O
H 2O
OH
d)
+
H O
O
page 6 of 8
16.
The following transformations cannot be done in a single step. Complete the following by
providing the correct reagents and the structure of the intermediate. (18 pts)
B 2H 6, THF;
then H 2O2,
NaOH, H 2O
3-hexyne
Ph 3P=CH 2
O
NaCN
Br
H 3C -MgBr, THF
then H 3O+
N
C
O
17. Give a complete, stepwise mechanism for the acid-catalyzed reaction of propionic acid and
methanol to afford methyl propionate. (12 pts)
H A
OH
O
H 3C OH
H A
OH
HO
OH2
O
H 3C
OH
OH
OH
HO
HO
O
H 3C
O H
:A –
H 3C
O
H
OCH3
:A –
O
OCH3
page 7 of 8
18. A molecule with the formula C12H17NO2 has the IR, 1H and 13C NMR spectra shown below. Provide
a structure that is consistent with the data. Please circle your final answer. (10 pts)
N-H
X H 2C-CH 3
C=O
~1660 cm-1
amide, possibly
conjugated.
X H 2C-H2C-CH 3
p-disubstituted
benzene
Amide
N-H
13
C NMR: δ 168.1, 154.2, 132.5, 125.8, 114.5, 64.6, 41.5, 23.1, 14.8, 11.2
13
C NMR: δ 168.1 : C=O, ester, acid, amide (acid is eliminated since there is no OH in IR)
O
N
H
O
page 8 of 8
___________________________________________________________________________________
Problem
1-15:_______ (60 pts)
16:_______ (18 pts)
17:_______ (12 pts)
18:_______ (10 pts)
Total out of 100: ______________