Download AE-December-2016-04-BS-12

National Exams December 2016
BS-12, Organic Chemistry
3 hours duration
NOTES:
1. If doubt exists as to the interpretation of any question, the
ent
candidate is urged to submit with the answer paper, a clear statem
of any assumptions made.
2. This is a CLOSED BOOK EXAM.
Any non-communicating calculator is permitted.
One aid sheet 8.5" x 11" hand-written on both sides.
3. TEN (10) questions constitute a complete exam paper.
be
The first 10 questions as they appear in the answer book will
marked.
4. Each question is of equal value.
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Question 1:
Many drugs are Bronsted-Lowry acids or bases.
a) What is the most acidic proton in the analgesic ibuprofen? Draw the
conjugate base.
b) What is the most basic electron pair in cocaine? Draw the conjugate
acid.
COON
ibupraun
oc,cairy
__
Question 2:
THC Is the active component in marijuana and ethanol is the alcohol in alcoholic
beverages. Explain why drug screenings are able to detect the presence of
THC but not ethanol weeks after these substances have been introduced into
the body
1
9H
Cit,
CKAH2—OH
\-P-
ImallydrOcannakinc4
THC
Question 3:
Although penicillin G has two amide functional groups, one is much more
reactive than the other. Which amide is more reactive and why?
Question 4:
Draw the products of each of these SN2 reactions and indicate the
stereochemistry where appropriate.
4-
d.
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-001i2
Question 5:
Propranolol, an antihypertensive agent is used in the treatment of high blood
pressure, can be prepared from 1-naphthol, epichlorohydrin and isopropylamine
using two successive nucleophilic substitution reactions. Devise a stepwise
synthesis of propranolol from these starting materials.
OH
H
Nti2
laapropyiEfrille
,:r11'191
Question 6:
What acetylide anion and alkyl halide are needed to synthesize each of the
following?
ECCH2CH2CH(CH3)2
CH3
b. CH3—C'---- C—C—CH2CH3
c.
C'ziC—CH2CH2CH3
Question 7:
compounds
Devise a synthesis of each compound from acetylene and organic
reagents.
required
other
containing two carbons or fewer. You may use any
Br
OH
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Question 8:
Match each compound to its IR-spectrum. Compound F is (CH3CH2) COH
pH,
0
o
cH3cH2cH2cH2--c-OH
cH2=c
CH(CH3)2
CH2CH2CH2CH3
(CH3)2CHOCH(CH3)2
-0C(CH3)3
o
A
Spectrum [11
Spectrum [21
% Transmittance
100
0
4000
3500
3000
2500 2000 1500
Wavenumber (cm-1)
1000
4000
500
3500
Spectrum [31
Spectrum [41
100
100
I /Mit
4000
3500
3000
2500 2000 1500
Wavenumber (cm-1)
0
trTi..
1000
2500 2000 1500
Wavenumber (cm-1)
irtIlltrilt..11TI
4000
500
3000
3500
Spectrum [5]
Spectrum [61
100
100
3000
11111,1
2500 2000 1500
Wavenumber (om-1)
•s
a
e
2
50
I
f
t t1
- 11- 1,{
0 I t I I f ti t I III- 111
4000 3500 3000 2500 2000 1500 1000
Wavenumber (cm-1)
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50
i.1
500
Wavenumber (cm-1)
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1000
1000
Question 9:
Treatment of 2-butanone (CH3 COCH2CH3) with a strong base followed by CH3I
forms a compound W which gives a molecular ion in its mass spectrum at 86.
The IR and 1H NMR spectra of W are given below. What is the structure of W.
Explain your reasoning.
__..._
H NMR o W
3H
6H
111
fit
4
PPm
1
% Transmittance
8'
3
2500
3000
Wavenumber (cm- )
Question 10:
product is 2When 3,3-dimethy1-1-butene is treated with HBr alone, the major
and
br6mo-2 ' 3-dimethylbutane. When the same alkene is treated with HBr
results
these
Explain
1-bromo-3,3-dimethylbutane.
peroxide, the sole product is
by referring to the mechanisms.
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Question 11:
Synthesize each compound from benzene and any other organic or inorganic
reagents.
NO2
NH2
a.
c.
g.
e.
3
Br
NH2
b.
Na
f.
d.
HOOC
(PABA)
sunscreen component
Question 12:
Explain the following:
a) The pKa of p-nitrophenol is lower than the pKa of phenol (7.2 vs 10).
vs
b) The pKa of p-nitrophenol is lower than the pKa of m-nitrophenol (7.2
8.3).
c) Carboxylic acids A and B are both more acidic than CH3CH2COOH
Question 13:
a
Compound A is a novel poly(ester amide) copolymer that can be used as
of
er
copolym
a
is
A
bioabsorable coating for the controlled release of drugs.
The
ives.
four monomers, two of which are amino acids or amino acid derivat
polymer
body's enzymes recognize the naturally occurring amino acids in the
r and the
backbone, allowing for controlled enzymatic breakdown of the polyme
to
used
ers
monom
four
the
Identify
steady release of an encapsulated drug.
synthesize A and name the two amino acids.
14 5
poly(ester amide) A
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