A greener pharmaceutical industry

Telescoping

Telescoping is the process of consolidating multiple reaction steps into fewer stages, minimising solvent use and waste, and the time and equipment needed to complete the reaction (Peterson et al., 2014). The inherently green chemistry approach that is telescoping permits the pharmaceutical industry to significantly reduce its manufacturing ecological footprint. Common approaches are listed below.

• One-pot syntheses: Telescoping often involves one-pot reactions where all reactants are combined in a single vessel instead of consecutive reactions with purification in-between. This minimises the need for transferring materials between different reactors, thus reducing the risk of losses and contamination (Hayashi, 2016). 

• Multicomponent reactions: These are key to telescoping strategies as they allow for the formation of complex molecules from three or more reactants in a single reaction step, enhancing efficiency and atom economy over consecutive reactions (Cimarelli, 2019) 

• Process intensification: Telescoping is a form of process intensification, which aims at making chemical processes more efficient. Techniques such as microwave-assisted synthesis and flow chemistry can also be incorporated to improve reaction rates and yield (Martins et al., 2022). 

There are environmental benefits to telescoping reactions. By reducing the number of reaction steps and solvent use, telescoping directly contributes to lowering the environmental footprint of pharmaceutical manufacturing (Ott et al., 2016). By extension, the consolidation of synthesis steps results in lower operational and capital expenses. It reduces the need for multiple reactors, decreases energy consumption, and minimises waste treatment costs.