CHEM1102 2014-J-8 June 2014 - Faculty of Science- … · CHEM1102 2014-J-8 June 2014 ... Draw the product of the reaction when diacyl chloride Q reacts with water. ... • Consider

CHEM1102 2014-J-8 June 2014

• Complete the following table. Make sure you give the name of the starting material where indicated.

Marks 4

STARTING MATERIAL REAGENTS/ CONDITIONS

STRUCTURAL FORMULA(S) OF MAJOR ORGANIC PRODUCT(S)

(CH3)2NH

hot 3 M NaOH

Cl

O

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.

Marks 7

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.

methylphenidate

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

• Complete the following table. Marks

1

STARTING MATERIAL REAGENTS/CONDITIONS THE MAJOR ORGANIC PRODUCT(S)

SOCl2

O

Cl


• 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.

3

Compound Organic products

O

O

H2N

N

OH O

O

CHEM1102 2013-J-9 June 2013


3


CONSTITUTIONAL FORMULA(S) OF MAJOR ORGANIC PRODUCT(S)

SOCl2

CH3NH2

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.

Marks 6

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.



1



SOCl2


• The polymer Nylon 66 can be made by mixing the following two reagents.

Draw the structure of Nylon 66.

Marks 2


• Consider the three compounds shown below.

Arrange these compounds in order of increasing acidity. Explain your reasoning.

Marks 3

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).


• 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.

Marks 4

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.


CHEM1102 2012-J-10 June 2012

• Complete the following table. If there is no reaction, write “NR”. Show any relevant stereochemistry.

Marks 7



Cr2O7

2– / H+

H+ catalyst / heat

(CH3)2NH / heat

CHEM1102 2012-J-12 June 2012

• Consider the following molecule (M) isolated from a natural source.

H2NN COOH

NH2

H

O

Marks 6

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.

(M)

CHEM1102 2012-J-13 June 2012

• Compound T is a precursor in the synthesis of the asthma drug salbutamol.

Marks 3

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.




1



SOCl2


• 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.

Marks 4

Compound Organic Product(s)


CHEM1102 2010-J-11 June 2010

• Give the constitutional formula(s) of the major organic product(s) formed in each of the following reactions.

Marks 7

1. LiAlH4

2. H / H2O

Br COOCH3

OH

10 M HCl

O

O

4 M NaOH

heat

N

H

Me

O6 M HCl

heat

O

O

excess CH3NH2


• Complete the following table. Marks2



OH

O

SOCl2

O

O

Cl

O

H / H2O / heat


• 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. Marks

4

STARTING MATERIAL REAGENTS/

CONDITIONS


1. dilute NaOH 2. CH3Br

Cr2O7

2 / H

1. Mg / dry ether 2. H2O

1. NaBH4 2. H+ / H2O

The final product may react further:

OH O

OHOH

O

Br

COOH

O

CO O H

O H O

Ow hic h m ig ht unde r goint ramolecular es te rif ic ationt o g ive t he c yclic es t e r

C O OH

OH

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.

Marks 7

COMPOUND ORGANIC PRODUCT(S)

CH3CH2COOH

CH C

H3C

H3C O

O Na

CH3CH2CO2

HN

CH3

CH3

CH3

Br

H3CN

CH3

CH3

CH C

H3C

H3C O

Cl

O

COH3C

O

COH3C

O+Na

Na

N

O

O

O

NH+Na

CHEM1102 2009-J-9 June 2009


• Consider the following reaction sequence.

OH

O

O

O

+ HCl

K

L M

N

+

Reagent A Reagent B

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.

Marks 6

A

SOCl2

B

1. LiAlH4 / dry ether 2. H+ / H2O

L

M

Cl

O

HO


• Give the constitutional formula(s) of the organic products formed in each of the following reactions

Marks 3

OCH3

O

NH2N

H

O

CH3OH+

BrNaCN

CN

O

O4 M NaOH

heat OOH

O+

CHEM1102 2008-J-8 June 2008

• Complete the following table. Make sure you indicate any relevant stereochemistry. Marks

4

STARTING MATERIAL REAGENTS/

CONDITIONS


CH3CH2COOH

1. SOCl2

2. CH3CH2OH

CH3CH2COOCH2CH3

O

O

CH3CH2CH2CH2CH2OH

CH3

CO

CCH3

OO

CH3

COCH2CH2CH2CH2CH3

O

+

CH3

COH

O

CH3 C

O

Cl H2O

CH3 C

O

OH

C

O

H

1. LiAlH4 / dry ether

2. H / H2O

CH2

OH

CHEM1102 2008-J-10 June 2008

• The structure of methyl 4-aminobenzoate, (E), is given below.

H2N

O

O

a

b

Marks 5

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.

H3N

O

O

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.

H2N

O

O

+ CH3OH

hot HCl (4 M)

Hydrolysis of ester. In acidic conditions, the carboxylic acid will not be deprotonated and the amine group will be protonated.

H3N

OH

O

+ CH3OH

(E)


• The structure of the antihistamine, ZyrtecTM, is given below.

Marks 5

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.

CHEM1102 2007-J-7 June 2007

• Draw the structure of the major organic product formed in the following reactions. Marks

5

O1. CH3MgBr

2. H / H2O

HO CH3

OH CH3CH2OH / H

O

O

O

O

1. NaBH4

2. H / H2O

OH

CHEM1102 2007-J-8 June 2007

• Suggest reagents you could use to achieve the following transformations.

OCH3

O

O

OA

Na

B

Br

OH

OC Dintermediate

compound

Marks 4

A: NaOH / H2O / heat

B: H2 / Pd catalyst

C: Mg / dry ether

D: 1.CO2 2. H / H2O

CHEM1102 2007-J-10 June 2007

• The amino acids serine and valine are shown below.

CO2HH2NH

CO2HH2NH

OH

serine valine

1 2

34

Marks 7

List the substituents attached to the stereogenic centre of valine in order of decreasing priority.

highest priority lowest priority

-NH2

-COOH -CH(CH3)2 -H

Assign the absolute configuration of the stereoisomer of valine shown above.

(S)

(anticlockwise)

Draw a dipeptide formed by the condensation of serine with valine.

H2N CH

CH2OH

CO NH CH COOH

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:

- αααα-helices, right handed coils stabilized by H-bonds between amide N-H and C=O groups four residues apart and

- ββββ-pleated sheets, extended structures stabilized by H-bonds between amide N-H and C=O groups on different chains


• The structure of salbutamol, a drug used to treat bronchospasms, is given below.

HO

HO

N

OH H

Marks 5

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.

cold HCl (1 M)

OH

N

H

HO

HO

H

NaOH (1 M)

OH

N

H

HO

O

Cr2O72 / H

O

N

H

HO

HO

O



2

Starting material Reagents / Conditions Major organic product(s)

COH

O

SOCl2 C

Cl

O

O

H

1. NaBH4

2. H / H2O OH



• Consider the reaction sequence below.

O

O

H

O

A + B

OH

Cl

2

Draw the structures of products A and B.

A

Cl

O

O

B

OH

O

• Draw the structure of the product, C, from the following reaction. 3

O

O

OCH3

excess H2

Pd/C catalyst

C

O

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.

HO

OCH3O

O


• 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.

Marks 5

Cl

O

NH3

ClO

NH

H

H

NH2

O

Cl +H+

ClO

NH

H


CHEM1102 2006-J-7 June 2006

• Draw the structure of the major organic product formed in the following reactions. Marks

5

OH

OSOCl2

O

Cl

H

OH O

2. H / H2O

1. LiAlH4

OH

OH

CHEM1102 2006-J-10 June 2006

• The amino acid serine is shown below:

COOHH2N

H

HO

(a) (b)

(c)

Marks 6

List the substituents attached to the stereogenic centre in order of decreasing priority.

highest priority lowest priority

NH2 COOH CH2OH H

Assign the absolute configuration of the stereoisomer shown above. S

Draw the dipeptide formed by the condensation of two serine residues.

NH2 CH CO NH CH COOH

CH2OH 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. 2

O

Cl

Cl

O

H2NNH2

+

O

O

N

H

N

H

n


• The structure of lignocaine, a local anaesthetic, is given below.

NN

H

Oa b

Marks7

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”.

cold HCl (1 M)

N

H

O

N H

hot NaOH (4 M) NH2

O

NO

hot HCl (4 M)

NH3

O

N HHO


• Draw the constitutional formula of the major organic product formed in each of the following reactions.

Marks 6

O

OH SOCl2

O

Cl

OHCH3COOH

H / heatO

O

OH Cr2O72 / H

O

COOH1. LiAlH4

2. H / H2O OH

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CHEM1102 2014-J-8 June 2014 - Faculty of Science- … · CHEM1102 2014-J-8 June 2014 ... Draw the product of the reaction when diacyl chloride Q reacts with water. ... • Consider