Supported Catalysts:
Improving the Synthesis of Drugs
Stephanie Lucas
[email protected]
School of Chemistry
Importance of Catalysts
Soluble vs Insoluble Catalysts
A catalyst increases the rate of a reaction without itself undergoing
any permanent change:
Starting material(s) + catalyst
Drug + catalyst
The worldwide demand for industrial catalysts is worth $29.5 billion1
Pharmaceutical companies rely heavily on catalysts as on average
there is 1 catalytic step in the synthesis of every drug candidate2
Soluble (dissolvable)
 Superior performance
× Hard to separate from soluble drug
× Separation usually destroys catalyst
Insoluble (remains solid)
 Easy to separate the drug (filtration)
 Catalyst can often be recycled
× Inferior performance
The pharmaceutical industry currently uses soluble catalysts. The separation
step is expensive, vastly increasing the price of the drug
Can the advantages of soluble and insoluble catalysts be combined by attaching a
soluble catalyst onto an insoluble support?
1. Attach Reactive Tether onto Catalyst
Tether
Add a tether onto existing catalyst
Reactive group at the end of the
tether
Site of
catalysis
Reactive
group
2. Support the Catalyst
Attach soluble catalyst onto an insoluble solid support using the reactive
group
Allows the superior performance of a soluble catalyst along with easy
separation of the drug (filtration)
Catalyst is not destroyed so it can be reused
3. Use Supported Catalyst in a Flow Reactor
Starting materials are continually pumped through the reactor
Drug flows out of the reactor but the supported catalyst stays inside
No drug separation step
The catalyst remains soluble in nature but has the advantages of drug separation
and catalyst recyclability associated with insoluble catalysts
Acknowledgements
Dr P. C. McGowan and Prof A.J. Blacker for supervision
Collaborators: University of Cambridge, AstraZeneca PLC,Pfizer Ltd. and Yorkshire Process Technology Ltd.
TSB for funding
References
1
"Global Catalyst Market," a June 2011 report from Acmite Market Intelligence, Ratingen, Germany
2 Org. Biomol. Chem., 2006, 4, 2337