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What’s In a Medicine?
Describe acids in terms of the Bronsted-Lowry theory as proton donors, and bases as proton acceptors, and
identify the proton donor/acceptor in an acid base reaction

Acids are molecules which donate a proton, whilst bases are molecules which accept a
proton
...

Acids have several properties:
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Turn litmus paper red
Free CO2 from carbonates
Donate a proton to a base
Have a pH lower than 7

Recognise and write formulae for the following homologous series: diols, diamines, dicarboxylic acids,
phenols, acid anhydrides, acyl chlorides, esters, aldehydes and ketones

Name

Formulae

Structure

Naming

Diol

HO – R – OH

Methane-1,2 -diol

Diamine

H2N – R – NH2

Methyldiamine

Dicarboxylic acid

HOOC – COOH

Ethanedioc acid

Phenol

C6H5OH

Phenol

Acid anhydride

R – C (O) – O – C (O) –
R’

Ethanoic anhydride

Acyl chloride

R – C (O) – Cl

Methanoyl chloride

Ester

R – C (O) – O – R

Methyl – xanoate

Aldehydes

R – C (O) – H

Methanal

Ketones

R – C (O) – R

Methanone

Describe and explain the acidic nature of carboxylic acids, and their reactions with alkalis and carbonates

Carboxylic acids contain a carbonyl group COOH, where the OH is able to donate a proton to
water in aqueous solution:

𝐶𝑂𝑂𝐻 + 𝐻2 𝑂 → 𝐶𝑂𝑂− + 𝐻3 𝑂+
H3O is another way of representing H+ ions in solution
...
The greater the delocalisation, the more stable the anion structure
and therefore more readily the acid donates a proton:
As carboxylate ions are able to delocalise
electrons across the double and single
bonded oxygen, they are the most stable
and therefore most acidic
...


Describe the reaction of carboxylic acids with alcohols under the presence of concentrated sulphuric acid or
HCl to produce esters

Carboxylic acids react with alcohols in an equilibrium reaction to produce an ester and
water:

This reaction can happen without the presence of a catalyst, but it often occurs too slowly
...

Describe the properties of phenols

Phenols are more acidic than alcohols but less acidic than carbonates, as the delocalised
electron ring provides more delocalisation than an alcohol but less than a carboxylic acid
...
Phenol is the only
acid to have the C=C-OH arrangement, which is able to react with Fe(III)Cl to give a purple
colouration
...

Ketones are formed by refluxing a secondary alcohol with acidified potassium dichromate:

For oxidation to occur, there must be a hydrogen on the carbon atom with the hydroxyl
group attached – therefore tertiary alcohols cannot be oxidised
...
Therefore pharmaceutical companies are reluctant to develop new drugs from
scratch; rather it is cheaper to develop a more effective medicine from one which already
exists
...


Understand reaction synthesis classification systems, understand atom economy and its applications in the
development of environmentally friendly industrial processes

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Substitution – replacing one atom group for another – 100% atom economy
Addition – adding atoms to another – 100%
Elimination – the loss of atoms from a molecule – less than 100%
Condensation – addition followed by elimination
Rearrangement – reorganisation of atoms within a molecule– 100%

Atom economy is defined as how efficiently reactant atoms are used in a chemical reaction:
𝐴𝑡𝑜𝑚 𝑒𝑐𝑜𝑛𝑜𝑚𝑦 =

𝑀𝑟 𝑜𝑓 𝑢𝑠𝑒𝑓𝑢𝑙 𝑝𝑟𝑜𝑑𝑢𝑐𝑡
× 100
𝑇𝑜𝑡𝑎𝑙 𝑀𝑟 𝑜𝑓 𝑟𝑒𝑎𝑐𝑡𝑎𝑛𝑡𝑠 𝑢𝑠𝑒𝑑

In terms of their atom economy in descending order it goes rearrangement/addition >
condensation/substitution > elimination
...
This minimises environmentally hazardous waste
products and increases efficiency of processes – improving profits
...

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Draw a pencil line 2cm above the base of a t
...
c plate (stationary phase)
Using a capillary tube, dot a sample of the solvent, reference mixtures and a sample
of the unknown substance on the line
Place the base of t
...
c plate in beaker of the same solvent (mobile phase) – ensuring
the solvent line does not touch the pencil line
Add a lid, to prevent evaporation and ensure the surrounding air is saturated in
solvent
Allow the solvent to move up the plate, as different components have different
affinities for the mobile phase so are separated into dots - remove when almost at
the top
Allow the plate to dry, then spray with a locating agent/shine uv/leave in an
enclosed space with iodine to reveal where the different compounds have separated

The Rf value is the distance to which a compound has moved relative to the solvent front
...

Interpret and predict mass spectra

Mass spectroscopy is a technique used to identify the Mr of molecules in a sample
...

The M+ peak is usually the peak with the
highest Mr, this represents the Mr of the
ionised molecule
...


The other smaller peaks can be several things
...
g
...

Where there are several isotopes of an atom, the relative atomic mass can be calculated
used the heights of the peaks:
(ℎ𝑒𝑖𝑔ℎ𝑡 × 𝑀𝑧) + (ℎ𝑒𝑖𝑔ℎ𝑡 × 𝑀𝑧)
100
Fragments often break up in the most stable formations, meaning structures such as CH 3 are
more likely to be formed than CH3CHCH2
...

Use the Data Sheet to interpret IR spectra for organic compounds

In infra-red spectroscopy substances are exposed to radiation which causes vibrational
energy changes in molecules which absorb infra-red
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