It is interesting to see how commercial fragment libraries are starting to evolve, from simple molecular weight cuts of available chemicals to more careful selection based on physicochemical properties. We now see several interesting design strategies being adopted.

Those based on a screening technology such as the LifeChemicals Fluorine-based library to support ¹⁹F NMR-based fragment screening, and the Maybridge Bromo-Fragment Collection a collection of over 1500 bromine containing Maybridge fragments constructed as an aid to X-ray based fragment screening.

Other libraries are designed for specific targets

OTAVA offers you new Chelator Fragment Library that comprises 575 compounds in total, Chelators demonstrate binding affinities suitable for FBLD screening and provide a diverse range of molecular platforms from which to develop lead compounds. Also, the propensity for chelators to bind metal ions allows for better prediction of their probable binding position within a protein active site in the absence of experimental structural data of the complex. 

Many attractive drug targets contain a free sulfhydryl group in the active site that confounds functional HTS assays due to its facile, non-specific oxidation leading to target inhibition. AnCore have developed a Targeted Covalent Inhibitor fragment library (TCI-Frag™) containing 100+ Rule-of-3 compliant fragments are conjugated with mildly reactive functionalities. The BIONET CNS Fragment Library is a focused library containing 700 Fragments selected for their suitability for Fragment Based Lead Discovery in the areas of CNS drug discovery and Universal target classes.

I’ve updated the Fragment Collections page