More than 1.3 Million
Small Molecules, Macrocycles
and Fragments for
 Hit Generation

Rule of Three Compliant Fragments for FBDD

ChemBridge offers more than 15,000 fragments that can be individually selected, allowing researchers to build fragment sets of size and composition best suited to their research objectives and methodologies. ChemBridge can also assist in the selection of subsets including structurally diverse subsets. This collection of small molecule fragments provides compounds for use in fragment-based screening and drug discovery using high-throughput X-ray crystallography, NMR, SPR and high concentration bioassay methodologies. Compounds included in the Fragment Library collection were chosen based upon the Astex Rule of Three¹ criteria plus additional physiochemical property and substructure filters.

Fragments meet Rule of Three¹ criteria (MW ≤ 300, H-bond donors ≤ 3, H-bond acceptors ≤ 3, cLogP ≤ 3) along with a rotatable bond count limit (RB ≤ 3) and a TPSA limit (TPSA ≤ 120) plus additional property and substruce filters. For the Brominated Subset, the MW upper limit was adjusted to 380.

View the Fragment Library product sheet

Higher Solubility Fragments

More than 5,000 fragments are available with higher DMSO and PBS solubility.

Fluorinated Subset

This subset of fragments offers an advantage for NMR-based fragment screens as 19F-NMR spectra have a wide range of chemical shifts which can be modified by the effects of neighboring atoms, particularly in the bound and unbound states of a fragment. Selection is based on the same criteria used for the overall Fragment Library collection.

Brominated Subset

A bromine-containing subset of fragments with potential use for X-ray crystallographic screening. The presence of the bromine atom in the X-ray analysis provides evidence for determining the location of the fragment bound to the target protein. Selection criteria is based on the same criteria used for the overall Fragment Library collection but with MW upper limit increased to 380 to allow for the contribution of the bromine atom.

  • Custom select fragments matching your research objectives and methodologies
  • Fragments are available in mg or micromole amounts in dry format or as DMSO solutions (in standard or deuterated DMSO)
  • Delivery in vials, tube racks, 384-well or 96-well plates available including acoustic qualified plates
Structure Files

For files of structures, please contact ChemBridge Sales.


¹Carr, R.A.E. et al., Drug Discovery Today, 2005, 10, 987-992