Nobel Prize 2022: Making chemistry click

Nobel Prize 2022: Making chemistry click

Subject: Science and Technology

Context– 

• The Nobel Prize 2022 in Chemistry has gone to three scientists who, through their work, have made a strong case for adopting an alternative approach to producing new complex molecules in the laboratory or industry, which minimises waste and increases overall efficiency.
• Carolyn Bertozzi and Barry Sharpless of the United States and Morten Meldal of Denmark have been given the Prize for developing the relatively recent field of ‘Click Chemistry’ and demonstrating its vast potential in the pharmaceutical and other industries.
• Sharpless, who is the originator of the concept of ‘Click Chemistry’, has now won the Nobel Prize for the second time, making him only the fifth scientist to achieve this distinction.
• His previous Nobel Prize had come in 2001 in recognition of a different kind of work.
• He emphasised on the need to replicate nature’s efficiency, not necessarily its processes, or even products.

What is ‘Click’ chemistry?

• The name (Click) has been taken from the click sound that airline seat belts make when they are fastened.
• The idea is that while trying to produce any particular compound or a complex molecule, one must look for starting molecules that easily react with each other.
• In other words, look for molecules that easily fit into each other, or ‘click’ with each other.
• It makes the resultant chemical reaction more efficient.

Why the idea of ‘Click’ Chemistry is so appealing?

• In the pharmaceutical industry, for example, which uses a lot of naturally occurring but industrially synthesised molecules, every kilogram of a drug produced results in the generation of nearly 25-100 kg of chemical waste. This is clearly not an efficient outcome.
• Sharpless was not just developing the ideas or identifying the criteria that would qualify a reaction to be called ‘Click’ reaction.

‘Click’ reactions–

• Barry Sharpless went ahead and found the first chemical reaction that satisfied the criteria he had laid out for ‘Click’ reactions.
• It was a modification to a chemical reaction that had been known for 40 years.
• This reaction was meant to produce a nitrogen-containing cyclic compound that was used as a building block for a variety of molecules in the drug industry.
• The usual process also produced several by-products. However, Sharpless discovered that the use of copper as a catalysteliminated the by-products altogether and only the desired chemical was produced.
• Interestingly, around the same time, this discovery was also reported by Morten Meldal, a Danish scientist working independently on some pharmaceutical substances.
• Meldal’s discovery was accidental, but once he realised the implications, he experimented with other molecules as well, and obtained quite a few successes.
• These initial successes generated a lot of interest, and several other ‘Click’ reactions were found by different researchers.
• The next big breakthrough in this field came a few years later, when Carolyn Bertozzishowed in 2004 that ‘Click’ Chemistry could work in the chemical processes happening in the living cells as well.
• She went on to develop a few ‘click’ reactions that work inside living organisms.
• Bertozzi’s methods, which she has repeatedly refined over the years, have shown the promise of treating advanced cancer.
• Cancer drugs based on her approach are now undergoing clinical trials.