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CHEM1002
2014-N-8
November 2014
• Complete the following table. Make sure you give the name of the starting material
where indicated.
STARTING MATERIAL
REAGENTS/
CONDITIONS
CONSTITUTIONAL
FORMULA(S) OF MAJOR
ORGANIC PRODUCT(S)
O
+
OH
NH 3
Marks
2
CHEM1002
•
2014-N-10
November 2014
The tropane alkaloid (–)-hyoscyamine is found in certain plants of the Solanaceae
family. It is an anticholinergic agent that works by blocking the action of
acetylcholine at parasympathetic sites in smooth muscle, secretory glands and the
central nervous system.
Hydrolysis of (–)-hyoscyamine results in two fragments, tropine and tropic acid.
Draw each of these fragments.
tropic acid
tropine
H
NCH 3
H
CH2OH
HO
OH
O
What is the stereochemistry at the tropic acid stereocentre? Write (R) or (S).
Is tropine optically active? Explain your answer.
Tropine is not optically active. It has no chiral centre and is identical to its
mirror image.
(S)
Marks
4
CHEM1002
2014-N-11
November 2014
• The amino acids alanine and phenylalanine can be reacted together to form two
dipeptides. Draw the structures of the two possible dipeptides.
H
N
CO2H
H 2N
O
H
N
CO2H
H 2N
O
THE REMAINDER OF THIS PAGE IS FOR ROUGH WORKING ONLY.
Marks
3
CHEM1002
2013-N-7
November 2013
• Complete the following table. Make sure you give the name of the starting material
where indicated.
STARTING MATERIAL
REAGENTS/
CONDITIONS
Cr2O72– / H+
Name: pentanal
O
excess (CH3)2NH
Cl
hot 3 M NaOH
CONSTITUTIONAL
FORMULA(S) OF MAJOR
ORGANIC PRODUCT(S)
Marks
5
CHEM1002
2013-N-10
November 2013
• The amino acids serine and valine can be reacted together to form 2 dipeptides. Draw
the structures of the 2 possible dipeptides.
H
H
THE REMAINDER OF THIS PAGE IS FOR ROUGH WORKING ONLY.
Marks
3
CHEM1002
2012-N-9
November 2012
• A number of functional groups react with hydroxide ion. Complete the following
table. NB: If there is no reaction, write "no reaction".
Starting Compound
Reaction Conditions
hot 4 M NaOH
1 M aqueous NaOH
hot 4 M NaOH
prolonged heating
Organic Product(s)
Marks
5
CHEM1002
•
2012-N-12
November 2012
Give the major organic product(s) from the following reactions. Pay particular attention
to the stereochemistry and/or the correct ionic from where relevant.
Marks
3
CHEM1002
2010-N-7
November 2010
• Give the name of the starting material where indicated and the constitutional
formula(s) of the major organic product(s) formed in each of the following reactions.
NB: if there is no reaction, write "no reaction".
O
O CH3
5 M NaOH
heat
Marks
1
CHEM1002
2010-N-9
November 2010
• Consider the following molecule (M) isolated from a natural source.
(M)
Indicate on the above structure all stereogenic centres in molecule (M).
Use numbered asterisks (*1, *2, etc.).
Select one of these stereogenic centres and determine its absolute configuration.
Show your working.
Priorities at *1: –NH2 > –CONHR > –CH(CH3)2 > –H
With H at back these groups go anticlockwise. Therefore (S)- configuration
about *1.
Priorities at *2: –NHCOR > –COOH > –(CH2)4NH2 > –H
With H at front these groups go clockwise. Therefore, with H at back, they
would go anticlockwise. Therefore (S)- configuration about *2.
Give the products when molecule (M) is hydrolysed by heating it with 6 M HCl.
Make sure you show the products in their correct ionisation states.
CHEM1002
•
2009-N-9
November 2009
Marks
Consider the following reaction sequence.
6
C
CH3OH
O
O
OH
Cl
B
aqueous NaOH
excess
D
(CH3) 2NH
1. LiAlH4
2 equiv.
2. H3O
E + F
A
Give the reagent B and draw the constitutional formulas of the major organic
products, A, C, D, E and F, formed in these reactions.
A
D
O
OH
O
B
•
E
O
SOCl2
N
C
•
F
O
Cl
OCH3
H N H
CHEM1002
2009-N-10
November 2009
• Compound (X) is a derivative of a naturally occurring Japanese beetle pheromone.
H3CO
O
(X)
H
What is the molecular formula of (X)?
OCH3
C16H30O3
What is the stereochemistry of the C–C double bond in (X)?
(Z)
List the substituents attached to the stereogenic centre in descending order of priority
according to the sequence rule.
highest priority
lowest priority
H3CO
OCH3
>
(CH2)7CH3
O
What is the absolute stereochemistry of (X)? Write (R) or (S).
On heating with 4 M H2SO4,
one of the products obtained is
compound (Y), whose structure
is shown on the right. Explain
the formation of this product.
H
>
>
(R)
O
O
(Y)
OCH3
The 4 M H2SO4 catalyses 2 reactions; (i) hydrolysis of the ester to a carboxylic
acid and (ii) addition of water across the C=C double bond to give the following
intermediate:
HO
O
1
2
3
6
4
5
HO
H
OCH3
ANSWER CONTINUES ON THE NEXT PAGE
Marks
7
CHEM1002
2009-N-10
November 2009
This intermediate can undergo an intramolecular esterification (the OH on
carbon 5 reacts with the carboxylic acid group at carbon 1) to give the cyclic
ester (Y).
O
2
1
O
5
3
4
6
OCH3
How many different stereoisomers are possible for compound (Y)?
4*
*There are stereogenic centres at C4 and C5.
CHEM1002
2009-N-11
November 2009
• Give the constitutional formula(s) of the organic products formed in each of the
following reactions.
NH2
H
OCH3
N
+
O
CH 3OH
O
H
OH
Na2Cr 2O7 / H3O
O
O
O
4 M NaOH
O
heat
O
+
O
OH
CHEM1002
2008-N-7
November 2008
• Give the name of the starting material where indicated and the constitutional formula
of the major organic product formed in each of the following reactions.
O
O
Cl
CH3CH2OH
(Formation of an ester from an acid chloride).
O
Marks
1
CHEM1002
•
2008-N-9
November 2008
Marks
Consider the following reaction sequence.
6
COOCH3
dilute H2SO4
heat
SOCl2
A
Reagent D
CH2OH
B
Reagent C
CON(CH3)2
conc. H2SO4
E
heat
Reagent F
Give the reagents C, D and F and draw the structures of the major organic products,
A, B and E, formed in these reactions.
A
D
COOH
(1). LiAlH4 / dry ether
(2). H+ / H2O
(Reduction of carboxylic acid to
primary alcohol).
(Hydrolysis of an ester to a
carboxylic acid).
B
E
O
Cl
(Formation of an acid chloride from
a carboxylic acid).
(Acid catalysed elimination of H-OH
(“dehydration”) to form C=C).
ANSWER CONTINUES ON THE NEXT PAGE
CHEM1002
2008-N-9
November 2008
F
C
CH 3
H N
CH 3
(Formation of amide from acid
chloride).
H2 / Pd/C
(Reduction of alkene to alkane).
CHEM1002
2008-N-12
November 2008
• Threonine (Y) is an amino acid. On the structure of (Y) below, identify all
stereocentres in threonine with an asterisk (*).
* OH
(Y)
H2N * COOH
How many possible stereoisomers of threonine
are there?
Two chiral centres so 4
possible stereoisomers (RR,
SS, RS and SR)
Give the structures of the products obtained when threonine is treated with the
following reagents.
1 M HCl
1 M NaOH
OH
OH
H 3N
COOH
(HCl is a strong acid so will protonate
the amine – a weak base. It will not
protonate the very, very weakly
acidic oxygen atoms at this
concentration).
H2N
CO2
OH- is a strong base and will
deprotonate the carboxlic acid – a
weak acid. It will not deprotonate the
very, very weakly acidic N-H or
alcohol O-H groups.
Marks
4
CHEM1002
•
2007-N-8
November 2007
Marks
6
Consider the following reaction sequence.
O
Br
OH / H2O
reagent B
OH
A
NaOH
reagent D
C
O
(CH3CH2)2NH
F
E
Cl
CH3OH
Give the reagents B and D and draw the structures of the major organic products,
A, C, E and F, formed in these reactions.
A
D
OH
B
SOCl2 / heat
E
O
Cr2O72– / H+
O
C
F
O
O
O
N
CH3OH
CHEM1002
2007-N-9
November 2007
• Dopa is a non-proteinogenic amino acid used to treat Parkinson’s disease. Only the
enantiomer (X) is effective in restoring nerve function. The other enantiomer is
highly toxic.
HO
HO
What is the molecular formula of (X)?
H2N H
(X)
OH
a
O
b
C9H11O4N
List the substituents attached to the stereogenic centre in descending order of priority
according to the sequence rules.
highest priority
lowest priority
NH2
COOH
CH2
OH
H
OH
What is the absolute stereochemistry of (X)? Write (R) or (S).
(S)
Name the functional groups, highlighted by the boxes a and b, present in (X).
a = arene (aromatic ring)
b = carboxylic acid
Give the constitutional formula of the product obtained when (X) is treated with
NaHCO3.
HO
H2N H
O
HO
O
Marks
7
CHEM1002
•
2006-N-8
November 2006
Marks
6
Consider the following reaction sequence.
B
1) LiAlH4
2) H / H2O
O
OH
reagent A
NaOH
C
H
O
reagent D
E
excess
H2NCH 3
Cl
CH3OH
F
O
Give the reagents A and D and draw the structures of the major organic products,
B, C, E and F, formed in these reactions.
A
D
Cr2O72- / H+
SOCl2
B
E
O
OH
CH3
N
H
C
F
O
O
CH3
O
O
CHEM1002

2005-N-7
November 2005
Marks
Draw the repeating unit of the polymer formed in the following reactions.
O
Cl
2
NH2
+
O
NH2
Cl
O
O
H
H
C
C
N
N
n
O
NH
O
H
C
N
n
CHEM1002
2005-N-8
November 2005
 Classify the starting materials of the following reactions as nucleophile or electrophile
and indicate with  and  the polarisation of the C–Br and C=O bonds.
CH3
H3C N
δ
Br
+
CH3
δ+
CH3
H3C N CH3
Br
electrophile
nucleophile
H
nucleophile
+
H3C δ δ
C O
H3C
H3C
H C O
H3C
H3C
H C O
H
H3C
H
electrophile
6
 Consider the following reaction sequence.
O
OH
NaOH
1) LiAlH 4
2) H
B
SOCl2
D
4
CH3
CH3
A
Marks
excess methanol
C
HN(CH 3)2
E
conc. HCl / heat
F
Draw the structures of the major organic products, A-F, formed in these reactions.
A
D
O
O
C
C
O
B
OCH3
E
CH2OH
O
C
N
CH3
CH3
C
F
O
O
C
C
Cl
OH
+
NH2(CH3)2
CHEM1002
2005-N-8
November 2005
CHEM1002
•
2004-N-6
November 2004
Marks
Draw the repeating unit of the polymer formed in the following reactions.
O
O
CH3O
O
O
NH
OCH3
NH
HN
+
H2N
NH2
O
O
HO
O
Cl
2
O