Synthetic routes

​​In a nutshell

A number of products from LED screens to cosmetics are produced via a multi-step reaction. The mapping of going from a starting material to the desired product is known as a synthetic route. Synthetic routes summarise what is required in each step of the process to form the desired product. 

Many factors need to be taken in to consideration during the design process, such as whether the materials are readily available, is the procedure safe, are safety measures required and will there be harmful consequences?

You will find a summary at the end, mapping out all the reactions you may come across during the course.

Synthesising compounds

In most cases products are not formed via a one step reaction. The starting material may undergo a series of reactions before the desired product is obtained. 

A synthetic route shows how you go from the starting material to the product and includes the following details (where applicable):

• Practical procedures and techniques for each reaction
  
• Reagents required for each reaction
• Intermediates 
• Conditions
• Safety precautions.  

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Chemists are hard at work

There are a variety of factors chemists need to take into consideration and implement when synthesising molecules. For instance, chemists need to ensure the synthetic route opted for will produce the correct isomer, which is very important in the pharmaceutical and cosmetic industry. This is because isomers can have different physical and/or chemical properties. This will affect how the molecule is manufactured and interacts with the ecosystem.

Stereoisomers also interact differently with biological molecules. A chemist is required to understand the intricacies of the types of mechanisms e.g. for a nucleophilic substitution they need to be able to identify and predict the orientation a molecule will be attacked at. It is important to produce single isomers wherever possible as the other isomers may have adverse effects. It also reduces the extra step of purification and down-time.

Safety precautions are taken to minimise risks posed by chemical reagents. Chemists also follow a set of principles to ensure the use of materials is sustainable and any harmful impact to the environment is minimal.

These safety measures and principles may include but are not limited to:

• Using non-hazardous starting materials and reagents wherever possible
• Ensuring waste products are not harmful
• Using a water bath or a hot plate to heat flammable substances
• Minimising solvent usage - many solvents are toxic and flammable
• Carrying out reactions in a fume cupboard if toxic gases are released  
• Ensuring high atom economy and percentage yield
• Keeping waste to a minimum
• Keeping energy consumption low.

Synthetic routes summarised: Aliphatic compounds 

Synthetic routes summarised: Aromatic compounds