Radio Cadena Agramonte emisiora de Camagüey
The great tool of science is its constant revision, which leads to scientific progress. Here is an example. Recently, there has been a breakthrough that changes the foundations of organic chemistry: a group of chemists from the University of California, Los Angeles (UCLA) has managed to violate one of the oldest and most respected rules of this discipline: Bredt's rule.
It was established about a century ago and defines that certain compounds with specific structures cannot contain double bonds without becoming unstable or highly reactive.
However, the research team has managed to synthesize compounds that contradict this theory, which is not only a remarkable technical feat, but also opens up new possibilities for chemistry and pharmacology.
The study, led by Professor Neil Garg and published in the prestigious journal Science, shows that these "anti-Bredt" compounds are stable and have useful properties.
This finding invites us to rethink concepts that seemed immutable in organic chemistry and represents an advance that will potentially impact drug design and the creation of complex three-dimensional molecules.
What is Bredt's rule and why is it important?
Bredt's rule, formulated in 1924 by German chemist Julius Bredt, states that double bonds in certain cyclic compounds with bridging structures, such as bicyclic compounds, tend to be unstable if placed in specific positions.
That is, in these structures, adding a double bond in certain places generates a tension in the molecule that makes it too reactive or directly impossible to synthesize.
The reason is that cyclic molecules have spatial limitations, and a double bond in the wrong spot would force the molecule to adopt a geometry that goes against the laws of classical organic chemistry.
This principle has been fundamental in organic chemistry for decades, guiding chemists in the design of new molecules. Researchers consider it a “filter” or “golden rule” in creating complex molecules.
However, the work of Garg and his team shows that under certain conditions, it is possible to create stable anti-Bredt compounds. This means it is time to reconsider how this rule is taught and applied in chemistry.
How the experiment was carried out
To challenge Bredt’s rule, the UCLA team began by designing specific compounds that, according to theory, should not exist under normal conditions. These compounds, called anti-Bredt olefins (ABOs), incorporate double bonds in positions where Bredt’s rule would indicate instability.
However, thanks to advanced synthesis and chemical manipulation techniques, they managed to stabilize these compounds.
The researchers used state-of-the-art synthesis methods to create the ABOs, using catalysts and isolation techniques that helped stabilize the compounds. This allowed them to observe how the double bonds remained stable in positions previously considered impossible.
According to the team, “achieving this stability in an anti-Bredt system could be the beginning of a revolution in molecular design.” This marks a significant change in how the structural limitations of molecules are addressed in organic chemistry.
Potential applications in pharmacology and organic chemistry
The stability of anti-Bredt olefins opens a new field in the design of three-dimensional molecules, which are especially valuable in the creation of medicines. These 3D structures have more complex and specific molecular interactions, which is useful in the design of drugs that need to selectively interact with proteins or receptors in the human body.
This allows scientists to navigate new routes in the creation of drugs with fewer side effects and greater efficacy.
But there is more: these compounds could help create materials with hitherto unknown properties. By offering a new way to manipulate molecular structures in three dimensions, the research of Garg and his team can extend beyond pharmacology into areas such as the creation of specialized polymers or materials with advanced electronic applications.
An impact on chemistry teaching and textbooks
One of the most immediate impacts of this discovery will be on chemistry education. For almost a century, Bredt's rule has been one of the foundations in organic chemistry courses.
This new development not only challenges traditional teaching, but also opens the door to including new techniques and methods that were previously unimaginable in basic chemistry courses.
Therefore, it is very likely that textbooks will have to be updated to reflect this change. The violation of Bredt's rule could even inspire students and professionals to question other principles that, although they have been considered immutable, could be overcome with the advancement of modern technology and techniques. (Text and Photo: Cubasí)
