From Organic Molecules to Medicines
15
From Organic Molecules to Medicines Chapter 14 – Heinemann Chemistry 2
description
From Organic Molecules to Medicines. Chapter 14 – Heinemann Chemistry 2. From Organic Molecules to Medicines. One very useful application of organic reaction pathways is in the design and synthesis of medicines. The main ingredients of medicines are drugs . - PowerPoint PPT Presentation
Transcript of From Organic Molecules to Medicines
From Organic
Molecules to Medicines
Chapter 14 – Heinemann Chemistry 2
From Organic Molecules to MedicinesOne very useful application of organic
reaction pathways is in the design and synthesis of medicines.
The main ingredients of medicines are drugs.A drug is any substance that alters a
chemical process in the body.
AspirinAspirin is widely used as a painkiller
(analgesic) and relieve inflammation and fever.It has its origins from a naturally occurring
substance called salicin.Salicin is converted to salicylic acid in the body
and this is the active substance that fights pain.Salicylic acid proved to be a more effective pain
killer than salicin but the acidic nature gave it an unpleasant taste and caused mouth and stomach irritations.
AspirinIt was found that the hydroxy group on the
salicyclic acid molecule will react with ethanoic acid to form an ester called acetylsalicylic acid.
The ester was much less irritating to the stomach and was tasteless compared to taking salicylic acid by itself.
The ester is then hydrolysed in the alkaline conditions in the small intestine and the salicylic acid can take effect.
Organic Pathway to AspirinAcetylsalicylic acid can be formed by a direct
condensation reaction between salycylic acid and ethanoic acid but the reaction is slow and the yield is low.
A more effective pathway is to form the ester from salicylic acid and ethanoic anhydride.
Organic Pathway to Aspirin
Hydrolysis of Aspirin
PenicillinPenicillin was discovered by accident when
scientist Alexander Fleming found a mould growing on a petri dish containing a culture of staphylococcus bacteria.
He found that the mould was killing the outer edges of the bacteria.
A few years later, an Australian scientist named Howard Florey improved processes to extract larger amounts of penicillin from this mould and used it for its antibiotic effects.
Penicillin
Figure 14.11 Fleming’s culture plate. The mould on the left (Penicillium notatum) is overcoming the growth of the smaller staphylococci.
PenicillinAs bacteria can reproduce every half an hour,
it has the ability to evolve much faster than humans. As such, it is able to build up a resistance penicillin.
To combat this, scientists synthesised different strains of penicillin with different side chains.
They also synthesised penicillin that could be taken orally instead of being injetced.
Penicillin
Figure 14.12 The molecular structures of penicillins F, G, and V. The structures were worked out by Dorothy Hodgkin (Figure 12.29), who also worked out the structures of insulin and vitamin B12.
Penicillin
Figure 14.13The structure of6-aminopenicillanic acid.
Figure 14.14Structure of oxacillin.
Greener Production of MedicinesWhen chemists first developed synthetic
pathways for making useful drugs, their main concern was to get a good yield.
Some methods contained a large amount of steps and as such produced a large amount of waste products.
This is referred to as poor atom economy.
Greener Production of MedicinesOver time, chemists have worked out greener
reaction pathways that are more efficient in terms of using fewer steps in the synthesis, greater yields and better atom utilization.
This has made large savings both in dollar terms and environmental impact.
Greener Production of Medicines
