Download CHEM1102 2014-J-8 June 2014 • Complete the following table

CHEM1102
2014-J-8
June 2014
• Complete the following table. Make sure you give the name of the starting material
where indicated.
STARTING MATERIAL
REAGENTS/
CONDITIONS
O
(CH3)2NH
Cl
hot 3 M NaOH
STRUCTURAL
FORMULA(S) OF MAJOR
ORGANIC PRODUCT(S)
Marks
4
CHEM1102
2014-J-9
June 2014
• Methylphenidate, also known as Ritalin, is a psychostimulant drug approved for the
treatment of attention-deficit disorder. Identify all stereogenic (chiral) centres in
methylphenidate by clearly marking each with an asterisk (*) on the structure below.
methylphenidate
Using one stereogenic centre you have identified, draw the (R)-configuration of that
centre.
How many stereoisomers are there of methylphenidate? Describe the relationships
between these isomers.
4 isomers: there are 2 pairs of enantiomers:
Each isomer has 1 enantiomer and 2 diastereoisomers
Give the products formed when methylphenidate is hydrolysed with 4 M HCl.
Marks
7
CHEM1102
2014-J-12
June 2014
• Show clearly the reagents you would use to carry out the following chemical
conversions. More than one step is required in each case. Give the structure of any
intermediate compounds formed.
Marks
3
CHEM1102
2014-N-8
November 2014
Marks
• Complete the following table.
STARTING MATERIAL
1
REAGENTS/CONDITIONS
THE MAJOR
ORGANIC PRODUCT(S)
O
SOCl2
Cl
CHEM1102
2014-N-9
November 2014
• Draw the structure of the organic product(s) formed when each of the following
compounds is treated with 4 M sodium hydroxide. The first reaction requires heating.
Compound
Organic products
O
H 2N
O
N
O
OH
O
3
CHEM1102
2013-J-9
June 2013
Marks
• Complete the following table.
STARTING MATERIAL
3
REAGENTS/
CONDITIONS
SOCl2
CH3NH2
CONSTITUTIONAL
FORMULA(S) OF MAJOR
ORGANIC PRODUCT(S)
CHEM1102
2013-J-14
June 2013
• Below is the reaction between an acid chloride and water to give a carboxylic acid.
Provide curly arrows for this mechanism and draw the structures of the two
intermediates on the pathway.
Indicate the hybridisation of the two oxygen atoms in the starting materials.
acid chloride: sp2
water: sp3
THE REMAINDER OF THIS PAGE IS FOR ROUGH WORKING ONLY.
Marks
6
CHEM1102
2013-N-8
November 2013
Marks
• Complete the following table.
STARTING MATERIAL
1
REAGENTS/
CONDITIONS
SOCl2
CONSTITUTIONAL
FORMULA(S) OF MAJOR
ORGANIC PRODUCT(S)
CHEM1102
2013-N-12
November 2013
• The polymer Nylon 66 can be made by mixing the following two reagents.
Draw the structure of Nylon 66.
Marks
2
CHEM1102
2013-N-12
November 2013
• Consider the three compounds shown below.
Arrange these compounds in order of increasing acidity. Explain your reasoning.
Ethanol is the weakest acid as its conjugate base is not resonance stabilised.
Phenol is a stronger acid as its conjugate base is resonance stabilised – the
negative charge can be delocalised into the aromatic ring as shown below.
There is even greater resonance stabilisation for the acetate ion (the conjugate
base of acetic acid), as the negative charge is delocalised onto the electronegative
oxygen atoms (as opposed to the carbon atoms in the case of phenol).
Marks
3
CHEM1102
2013-N-13
November 2013
• The incomplete mechanism for the reaction of acetyl chloride with hydroxide ions is
shown below. The reaction occurs in three steps. In each step complete the
mechanism by adding curly arrows to indicate the bond changes taking place.
Marks
3
CHEM1102
2012-J-9
June 2012
• Indicate the hybridisation of the carbon and nitrogen atoms in the diamine P.
Draw the product of the reaction when diacyl chloride Q reacts with water.
Kevlar (used in bullet-proof vests) is a polyamide polymer which is made from diacyl
chloride building block Q and diamine building block P. Draw the repeating polymer
unit formed in the reaction of P with Q.
THE REMAINDER OF THIS PAGE IS FOR ROUGH WORKING ONLY.
Marks
4
CHEM1102
2012-J-10
June 2012
• Complete the following table. If there is no reaction, write “NR”. Show any relevant
stereochemistry.
STARTING MATERIAL
REAGENTS/
CONDITIONS
Cr2O72– / H+
H+ catalyst / heat
(CH3)2NH / heat
CONSTITUTIONAL
FORMULA(S) OF MAJOR
ORGANIC PRODUCT(S)
Marks
7
CHEM1102
2012-J-12
June 2012
• Consider the following molecule (M) isolated from a natural source.
H
N
H2N
COOH
O
(M)
NH2
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.
Marks
6
CHEM1102
2012-J-13
June 2012
• Compound T is a precursor in the synthesis of the asthma drug salbutamol.
Give the molecular formula of compound T. C11H12O4
Give the structure(s) of all organic products formed when compound T is heated with
4 M NaOH.
THE REMAINDER OF THIS PAGE IS FOR ROUGH WORKING ONLY.
Marks
3
CHEM1102
2012-N-10
November 2012
Marks
• Complete the following table.
STARTING MATERIAL
1
REAGENTS/
CONDITIONS
SOCl2
CONSTITUTIONAL
FORMULA(S) OF MAJOR
ORGANIC PRODUCT(S)
CHEM1102
2012-N-11
November 2012
• Draw the structure of the organic product(s) formed when each of the following
compounds is treated with 4 M sodium hydroxide. The first two reactions proceed at
room temperature; the last one requires heating.
Compound
Organic Product(s)
THE REMAINDER OF THIS PAGE IS FOR ROUGH WORKING ONLY.
Marks
4
CHEM1102
2010-J-11
June 2010
•
Give the constitutional formula(s) of the major organic product(s) formed in each
of the following reactions.
Br
COOCH3
1. LiAlH4
2. H / H2O
10 M HCl
OH
O
4 M NaOH
O
heat
O
N
Me
6 M HCl
heat
H
O
O
excess CH 3NH 2
Marks
7
CHEM1102
2010-N-9
November 2010
Marks
• Complete the following table.
STARTING MATERIAL
2
REAGENTS/
CONDITIONS
O
CONSTITUTIONAL
FORMULA(S) OF MAJOR
ORGANIC PRODUCT(S)
O
SOCl2
Cl
OH
O
O
H / H2O / heat
CHEM1102
2010-N-10
November 2010
• The following is a nucleophilic addition-elimination reaction between ammonia and
an acid anhydride. Provide curly arrows needed for the mechanism, and draw the
structures of the two intermediates on this pathway.
Marks
5
CHEM1102
2009-J-8
June 2009
• Complete the following table. Make sure you indicate any relevant stereochemistry.
STARTING MATERIAL
OH
REAGENTS/
CONDITIONS
CONSTITUTIONAL
FORMULA(S) OF MAJOR
ORGANIC PRODUCT(S)
O
1. dilute NaOH
2. CH3Br
O
OH
Br
Cr2O72 / H
OH
1. Mg / dry ether
2. H2O
OH
O
COOH
1. NaBH4
2. H+ / H2O
COOH
The final product may react further:
which might undergo
intramolecular esterif ication
to give the cyclic es ter
OH
COO H
O
O
Marks
4
CHEM1102
2009-J-9
June 2009
•
Give the constitutional formula(s) of the organic product(s) formed when each of
the following compounds is treated with 4 M sodium hydroxide. The first three
reactions proceed at room temperature; the last two require heating.
COMPOUND
ORGANIC PRODUCT(S)
CH3CH2COOH
CH3CH2CO2
H
CH3
CH3
N
Br
CH3
H3C
H 3C
CH 3
H3C
O
H3C
Cl
O
H 3C
C
O
CH C
CH C
H3C
CH3
N
O
Na
O
O
H3C
O
C
O
Na
+
Na
O
O
N
O
Na
+
H N
Marks
7
CHEM1102
2009-J-9
June 2009
CHEM1102
2009-N-9
November 2009
Marks
• Consider the following reaction sequence.
6
O
OH
K
Reagent A
Reagent B
L
M
+
O
+
O
HCl
N
Compound K below can be converted into two different intermediates, L and M,
which can react together to give compound N and the inorganic byproduct HCl.
Give the reagents A and B and draw the structure of the intermediates L and M.
A
B
SOCl2
1. LiAlH4 / dry ether
L
M
O
Cl
HO
2. H+ / H2O
CHEM1102
2009-N-10
November 2009
• Give the constitutional formula(s) of the organic products formed in each of the
following reactions
H
NH2
N
+
OCH3
CH 3OH
O
O
Br
CN
NaCN
O
4 M NaOH
O
heat
O
+
O
OH
Marks
3
CHEM1102
2008-J-8
June 2008
• Complete the following table. Make sure you indicate any relevant stereochemistry.
STARTING MATERIAL
REAGENTS/
CONDITIONS
CONSTITUTIONAL
FORMULA(S) OF MAJOR
ORGANIC PRODUCT(S)
CH3CH2COOCH2CH3
1. SOCl2
CH3CH2COOH
O
2. CH3CH2OH
O
O
O
CH3CH2CH2CH2CH2OH
CH3
C
CH3
O
O
C
C
OCH2CH2CH2CH2CH3
O
CH3
+
CH3
C
OH
O
O
CH3
C
H2O
Cl
O
1. LiAlH4 / dry ether
H
2. H / H2O
C
CH3
C OH
OH
CH2
Marks
4
CHEM1102
2008-J-10
June 2008
• The structure of methyl 4-aminobenzoate, (E), is given below.
O
(E)
O
b
H2N
a
Give the molecular formula of compound
(E).
C8H9NO2
Name the functional groups in molecule (E) indicated by the boxes “a” and “b”.
a: amine
b: ester
Give the structure(s) of all organic products formed when compound (E) is treated
with the following reagents. If no reaction occurs, write “NO REACTION”.
cold HCl (1 M)
No hydrolysis of the ester under these conditions. The
amine group will be protonated by the strong acid.
O
O
H3N
hot NaOH (4 M)
Treatment with base will lead to hydrolysis of the ester.
In the basic solution, the carboxylic acid will be
deprotonated and the amine will not be protonated.
O
O
+ CH3OH
H2N
hot HCl (4 M)
Hydrolysis of ester. In acidic conditions, the carboxylic
acid will not be deprotonated and the amine group will
be protonated.
O
OH + CH3OH
H3N
Marks
5
CHEM1102
2008-N-10
November 2008
• The structure of the antihistamine, ZyrtecTM, is given below.
What is the name of the functional group in Box A?
Amine (tertiary)
What is the name of the functional group in Box B?
Ether
What is the name of the functional group in Box C?
Carboxylic acid
By drawing an arrow on the structure above, clearly indicate the stereocentre in the
structure of Zyrtec.
Draw the product of the reaction when Zyrtec is treated with LiAlH4 followed by
dilute acid.
LiAlH4 will reduce the carboxylic acid all the way to an alcohol.
Marks
5
CHEM1102
2007-J-7
June 2007
• Draw the structure of the major organic product formed in the following reactions.
HO
O
CH3
1. CH3MgBr
2. H / H2O
O
O
OH
CH3CH2OH / H
O
O
1. NaBH4
2. H / H2O
OH
Marks
5
CHEM1102
2007-J-8
June 2007
Marks
• Suggest reagents you could use to achieve the following transformations.
O
4
O
A
OCH3
O Na
B
O
Br
C
intermediate
compound
D
OH
A: NaOH / H2O / heat
B: H2 / Pd catalyst
C: Mg / dry ether
D: 1.CO2 2. H
/ H2O
CHEM1102
•
2007-J-10
June 2007
Marks
The amino acids serine and valine are shown below.
7
OH
H
H2N
4
CO2H
serine
H
H 2N
1
3
CO2H
2
valine
List the substituents attached to the stereogenic centre of valine in order of decreasing
priority.
highest priority
-NH2
lowest priority
-COOH
-CH(CH3)2
Assign the absolute configuration of the stereoisomer of valine
shown above.
-H
(S)
(anticlockwise)
Draw a dipeptide formed by the condensation of serine with valine.
H2N CH
CO NH CH COOH
CH2OH
What are the two key elements of protein secondary structure?
The secondary structure describes the orientation of segments of the peptide
chain and is defined by the H-bonding between amino acid residues. The
most common secondary structures are:
-
α-helices, right handed coils stabilized by H-bonds between amide NH and C=O groups four residues apart and
-
β-pleated sheets, extended structures stabilized by H-bonds between
amide N-H and C=O groups on different chains
CHEM1102
2007-N-9
November 2007
• The structure of salbutamol, a drug used to treat bronchospasms, is given below.
OH
H
N
HO
HO
Give the molecular formula of salbutamol.
C13H21O3N
Calculate the m/z value for the major peak you would expect to see for the molecular
ion in the high resolution mass spectrum.
[Atomic masses: 1H = 1.0078; 12C = 12.0000; 16O = 15.9949; 14N = 14.0031]
The molar mass of C13H21O3N is
13 × 12.0000 (C) + 21 × 1.0078 (H) + 3 × 15.9949 (O) + 1 × 14.0031 (N)
Answer: 239.1516
Give the structure(s) of the major organic products formed when salbutamol is
treated with the following reagents.
OH
cold HCl (1 M)
H
N
HO
H
HO
OH
NaOH (1 M)
H
N
HO
O
O
Cr2O72 / H
O
H
N
HO
HO
Marks
5
CHEM1102
2007-N-10
November 2007
Marks
• Complete the following table.
Starting material
2
Reagents / Conditions
O
C
Major organic product(s)
O
OH
H
SOCl2
C
Cl
1. NaBH4
O
2. H / H2O
OH
THE REMAINDER OF THIS PAGE IS FOR ROUGH WORKING ONLY.
CHEM1102
2007-N-11
November 2007
• Consider the reaction sequence below.
2
O
O
OH
O
A
Cl
+
B
H
Draw the structures of products A and B.
A
B
O
O
OH
O
Cl
• Draw the structure of the product, C, from the following reaction.
C
O
O
excess H2
O
OCH3
Pd/C catalyst
O
OCH3
Product C undergoes hydrolysis when heated with 4 M NaOH. Give the structures of
the products (in their correct ionic states) formed in this reaction.
O
HO
O
OCH3
3
CHEM1102
2007-N-12
November 2007
• The incomplete proposed mechanism for the reaction of acetyl chloride with
ammonia is shown below. Complete the mechanism by adding curly arrows to
illustrate the bonding changes that take place.
O
O
Cl
H
Cl
N
H
NH3
O
O
Cl
+
H
NH2
Cl
N
+ H
H
H
THE REMAINDER OF THIS PAGE IS FOR ROUGH WORKING ONLY.
Marks
5
CHEM1102
2006-J-7
June 2006
• Draw the structure of the major organic product formed in the following reactions.
O
O
SOCl2
OH
OH
Cl
OH
O
1. LiAlH 4
H
2. H / H 2O
OH
Marks
5
CHEM1102
•
2006-J-10
June 2006
Marks
The amino acid serine is shown below:
HO
(c)
6
H
H2N
(a)
COOH
(b)
List the substituents attached to the stereogenic centre in order of decreasing priority.
highest priority
lowest priority
NH2
COOH
CH2OH
H
S
Assign the absolute configuration of the stereoisomer shown above.
Draw the dipeptide formed by the condensation of two serine residues.
NH2 CH
CO
NH
CH
CH2OH
COOH
CH2OH
Explain briefly what is meant by the primary structure of a protein.
The primary sequence is the sequence in which the amino acids occur. For
example, ala-ser-tyr:
•
Draw the repeating unit of the polymer formed in the following reaction.
O
Cl
Cl
O
+
NH2
H2N
O
H
N
N
O
H
n
2
CHEM1102
2006-N-7
November 2006
Marks
• The structure of lignocaine, a local anaesthetic, is given below.
7
H
N
N
O
b
a
Give the molecular formula of lignocaine.
C14H22ON2
Name the functional groups in lignocaine indicated by boxes “a” and “b”.
a: amide
b: tertiary amine
Give the structure(s) of all organic products formed when lignocaine is treated
with the following reagents. If no reaction occurs, write “NO REACTION”.
H
cold HCl (1 M)
N
N
H
O
O
hot NaOH (4 M)
NH2
N
O
hot HCl (4 M)
HO
NH3
N
O
H
CHEM1102
2006-N-8
November 2006
• Draw the constitutional formula of the major organic product formed in each of the
following reactions.
O
O
OH
Cl
SOCl2
O
OH
CH3COOH
H / heat
OH
Cr2O7
COOH
2
O
O
/H
1. LiAlH 4
2. H / H 2O
OH
Marks
6