Novel Drug Synthesis
A new catalyst could reduce waste and lead to new drugs based on natural products
Source: “A Predictably Selective Aliphatic C-H Oxidation Reaction for Complex Molecule Synthesis”
Mark S. Chen and M. Christina White
Science 318: 783-787
Results: A new iron-based catalyst developed by researchers at the University of Illinois at Urbana-Champaign enables researchers to predictably alter the cores of complex molecules by oxidizing specific carbon-hydrogen bonds.
Why it matters: Complex molecules produced by plants and other organisms are often good candidates for new drugs. But they frequently need to be chemically modified before they’re effective enough for therapeutic use. In the past, making the necessary modifications could require synthesizing the entire molecule from scratch, often a difficult process requiring multiple steps. The new catalyst makes these modifications easier.
Methods: The researchers synthesized a catalyst that was both relatively large and attracted to electrons. Then they derived a list of rules predicting precisely which bonds in complex molecules the catalyst would oxidize. They showed that in general it oxidized the carbon-hydrogen bond at the most electron-rich area of a complex molecule. If, however, the most electron-rich area was difficult to reach, the catalyst oxidized the most accessible C-H bond. Finally, if the molecule included a carboxylic acid group, the catalyst oxidized a bond a certain distance from the acid. The researchers confirmed that the rules allow chemists to predict exactly which bond will be modified.
Next steps: Researchers at other academic institutions and drug companies are beginning to use the catalyst in their work. The University of Illinois researchers are considering new catalysts that work on similar principles.