Advanced Metal Scavengers

Metal catalysts are used extensively to generate a wide range of products across a variety of industries. In the pharmaceutical and fine chemical industries, metal catalysts play an important role in operations from early discovery through development to full scale manufacture. Precious metal catalysts in particular are used to promote many key transformations towards the synthesis of new active pharmaceutical ingredients (APIs).

Palladium is one of the most widely used precious metals for reactions such as deprotections and hydrogenations, as well as carbon-carbon bond forming reactions by Heck, Suzuki and Sonogashira couplings and carbon-nitrogen bond formations by Buchwald-Hartwig aminations. The mild reaction conditions, high functional group tolerance and high yields offered by these now highly advanced cross-coupling technologies also means that metal catalysed reactions are now being used increasingly later on in complex API synthetic routes.

Up until recently the major drawback of metal catalysed chemistry has been that toxic metal residues are invariably left bound to the desired reaction product, which will typically contain a number of functional groups, often in close proximity, and capable of binding strongly to precious metal catalyst residues.

Traditional methods for the removal of metals from APIs include distillation, extraction, adsorption onto activated charcoal and crystallization. However, these methods suffer from severe disadvantages including significant product loss; performance issues, primarily an inability to achieve the very low levels of residual metal required by regulators; time and practicality issues.

PhosphonicS multi-functional silicas, designed containing ligands with an overall higher affinity for metal compared to the pharmaceutical product, successfully overcome these metal removal issues and provide an attractive, reliable, practical and cost-effective first option for scavenging residual metals from all pharmaceutical products.