Much has been written in recent years about SF5 as the “substituent of the future.” By bringing the troika of enhanced lipophilicity, electronegativity, and metabolic stability into medicinal chemistry, the SF5 functional group has been widely considered to offer a path to the discovery of new chemical entities with features that are desirable in drug development. Introducing SF5 into a compound to replace an isopropyl or t-butyl group, or even a CF3 group, has led to improved efficacy in a number of cases (mefloquin are finpronil are two such examples). SF5 has even been referred to as a “Super Trifluoromethyl Group.” The main disadvantage of SF5-sbstituted compounds is that they are difficult to synthesize. SF5 is challenging to incorporate readily into prospective drug compounds, as the conditions under which it can be added are harsh. As a result, only a limited number of SF5-containing compounds have been tested, and the utility of SF5 as a broadly-useful substituent to improve the properties of biologically-active compounds has fallen short of expectations.
But a new substituent that can bring more broadly applicable benefits is now available, with particular utility for medicinal chemists and developers of new crop protection agents.
The pentafluoroethyl (-CF2CF3) group offers similar benefits to as -SF5
- Comparable lipophilicity to SF5 (ClogP)
- Slightly less electronegative than SF5
- High chemical and metabolic stability
- Size intermediate between CF3 and t-butyl
but with one enormous advantage: Broad Synthetic Access With new Pentafluoroethylation Technology, Catylix offers a practical way to introduce the pentafluoroethyl group into most vinyl, aryl, and heteroaryl compounds, and in almost any position. Furthermore, the synthetic methods developed by Catylix promise to be
To help chemists evaluate -C2F5 as the new substituent of the future, Catylix is launching a new product line focused on pentafluoroethyl substituents. Compounds are pre-functionalized with the -C2F5 group and contain an additional “chemical handle” allowing the straightforward incorporation of the pentafluoroethyl fragment into the synthetic route of a more complex molecule.
We call them Penta-F-Blocks
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