For more than a century, chemists have built complex molecules step by step, forming new chemical bonds and assembling each variation individually. When researchers want to evaluate multiple versions of a promising compound, they often must repeat much of the synthetic process for every new candidate. This approach can slow drug discovery and other areas of chemical research. Researchers at the University of Vienna have now developed a molecular editing strategy that allows chemists to modify existing molecules instead of rebuilding them from the beginning.
The challenges of modifying amines
The new study, published in Nature Chemistry, describes a method for directly and selectively modifying secondary N-methylamines. These compounds are widely found in biologically active molecules, including many pharmaceuticals and neurotransmitters. Traditional approaches for modifying these amines often require multiple synthetic steps, specialized catalysts, or reaction conditions that exclude water and oxygen.
To simplify the process, the research team, led by Nuno Maulide, PhD, professor at the University of Vienna, developed a strategy that replaces a methyl group on an amine with a more complex alkyl fragment without reconstructing the rest of the molecule. The researchers call this transformation an "alkyl swap."
A simpler approach to late-stage molecular editing
The technique uses simple alkenes—stable and readily available hydrocarbons—to exchange the methyl group of an amine for more complex carbon-based fragments. Because the reaction selectively targets a single position while leaving the remainder of the molecule intact, it enables late-stage modification of complex compounds that have already been synthesized.
"What's fascinating is the simplicity," said Daniel Kaiser, PhD, a co-author of the study. "You can modify highly complex molecules at a very specific point without touching the rest of the molecule."
According to the researchers, the reaction proceeds under relatively mild conditions and does not require specialized atmospheres or complex experimental setups, an approach the team informally describes as "bathtub chemistry." Uroš Vezonik, a PhD student and co-first author of the study, noted that methods for directly modifying these amines are valuable because they are common structural features in biologically active molecules.
The researchers demonstrated the technique on derivatives of several widely used pharmaceuticals, including fluoxetine, sertraline, and citalopram. They also showed that the method could be used to generate medicinally relevant molecular libraries and synthesize peptide-drug conjugates.
What this means for laboratory managers
For laboratory managers overseeing synthetic chemistry operations, the new method highlights how molecular editing strategies may simplify certain research workflows. By modifying existing molecules rather than synthesizing each variant from the beginning, chemists may be able to reduce the number of synthetic steps required during lead optimization and other late-stage development efforts.
Because the reaction operates under relatively mild conditions and does not rely on specialized atmospheres, laboratories may also be able to perform these transformations without some of the equipment or handling requirements associated with more sensitive synthetic methods. While additional research will determine how broadly the approach can be applied, the technique offers another tool for efficiently exploring chemical diversity during pharmaceutical and medicinal chemistry research.
This article was created with the assistance of Generative AI and has undergone editorial review before publishing.
