Download 1-15) are True or False (15pts)

Sp 2011 Organic II Exam #3
Ch 20-21
(100 points)
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1-15) are True or False (15pts)
1)
Carboxylic acids are proton donors.
2)
Carboxylic acids are Lewis acids.
3)
Esters undergo SN1 reactions at the C=O bond.
4)
Primary amides have an sp hybridized Nitrogen atom.
5)
Nitriles have 2 σ and 1 π covalent bonds.
6)
Ethanenitrile is more basic than pyridine.
7)
Cyclic Esters are called Tone-locs.
8)
Carboxylic acids can be reduced to primary alcohols by NH3.
9)
The reaction where one ester is transformed into another ester is
called cis-esterification.
10)
Nucleophilic acyl substitution reactions proceed through a linear
intermediate.
11)
The nucleophilic acyl substitution mechanism is an example of a
concerted mechanism.
12)
Nitriles can be hydrolyzed to amides.
13)
The Carbon/Nitrogen bond lengths decrease from amines to amides to
nitriles.
14)
Grignard reagents are “organometallic” compounds.
15) Compounds with an amino group, and a carboxylic acid group are
known as amino acids.
Sp11org2e3.doc
Page 1
16) Name the general class of organic compounds that each of these
molecules belong to. (15pts)
O
O
R C NR2
O
O
R C O C R
O
O
R C O-R
O
R C Br
NH
R C N
O
R
N
R C R
O
R C NH2
O
R C OH
17) Put a cross through the molecule that contains the weakest π bond. (2pts)
Sp11org2e3.doc
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18) Circle the stronger acid in the following pairs. (12pts)
(a)
(b)
(c)
H3C CO2H
NC
CO2H
CO2H
CBrH2CH2 CO2H
CH3CBrH CO2H
NH2
(d)
F
(e)
F3C CO2H
OH
F
Cl
CO2H
O
(f)
Cl
CO2H
O
O
OH
OH
19) (3pts) Draw a Lewis structure for the most acidic molecule with the
molecular formula C4H6O2Br2
Sp11org2e3.doc
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20) Name the following compounds in IUPAC acceptable terms. (18pts)
Br
F
NH2
O
O
O
O
O
O
OH
H2N
NH
O
O
**BONUS 2 POINTS** for providing the trivial Biological name for the
last compound which is the chief inhibitory neurotransmitter in the
mammalian central nervous system.
21) Circle the most reactive molecule with respect to nucleophilic acyl
substitution in the following threesomes. (9pts)
O
(a)
(b)
O
O
H3C C Cl
H3C C H
O
H3C C OH
H3C C CH3
O
O
H3C C O C CH3
O
H3C C OCH3
O
O
(c)
H3C O C CH
3
O
O
Sp11org2e3.doc
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22) Benzoic acid can be made from a wide variety of benzene derivatives.
Fill in the missing starting materials. (12pts)
-
OH/H2O
1) Mg
2) CO2
3) H3O+
CO2H
KMnO4, H3O+
Heat
Ag2O
23) (2+2 pts) Provide two reasons which explain why amides are less
reactive than esters in nucleophilic acyl substitution reactions.
Sp11org2e3.doc
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24) Draw in all the curly arrows for the following mechanism of an acid
catalyzed esterification. (10pts)
O
H-X
R C O-H
+ H
O
R C O-H
H
O
R C O-H
+
H
O
R C O-H
+
:X
R'-O-H
H + H
O
R C O-H
O
R'
H-X
H
O
R C O-H
O
R'
H
O
R C O-H
O
R' + H
:X
+
R C O-H
O
R'
+
R C O-H
O
R'
R C O-H
O
R' +
:X
O
H-X
Sp11org2e3.doc
R C O-R'
Page 6
*Bonus question* (up to 2pts)
Explain why the amide below exists as two observable stereoisomers.
O
H C NHCH3
Extra bonus Question (2pts) – describe experimentally how you can
“observe” these different stereoisomers.
Sp11org2e3.doc
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