semisynthèse

Semisynthesis refers to a chemical process where a natural product is used as a starting material to create a new compound. This approach combines the advantages of both natural product isolation and total synthesis. Natural products often possess complex and unique molecular structures that are difficult or impossible to create entirely through total synthesis. Semisynthesis leverages the pre-existing structural complexity of these natural molecules, allowing chemists to modify them into new derivatives with potentially improved or altered properties.

The process typically begins with the extraction and purification of a target natural product from a biological source, such as plants, microorganisms, or marine organisms. Once isolated, this natural precursor undergoes a series of controlled chemical reactions. These reactions aim to modify specific functional groups, introduce new substituents, or alter the existing molecular scaffold. The goal is often to enhance a compound's therapeutic efficacy, improve its bioavailability, reduce toxicity, or create analogs with novel pharmacological activities.

Semisynthesis is a widely used strategy in drug discovery and development. Many important pharmaceuticals, including certain antibiotics, anticancer agents, and antiviral drugs, are derived from natural products through semisynthetic modifications. This method allows for the efficient exploration of chemical space around a biologically active natural core, accelerating the identification of lead compounds and the development of new medicines. It is particularly valuable when the natural product itself has limitations that can be overcome by chemical alteration.