Ultimate Fragment Library

FBDD allows a reduction of the screening library size and coverage of larger unexplored and underrepresented chemical space. It provides more straightforward starting points for subsequent chemical optimization of initial hits.

The process of fragment synthesis obeys a heuristic rule called the Rule of Three. A state-of-the-art tuning of the Rule of Three parameters helps to generate small-molecule compounds with improved ADME profile for efficient lead identification by FBDD and HTS.

The Life Chemicals Ultimate Fragment Library was designed by applying the ultimately refined picking approach to our HTS Compound Collection: the Rule of Three and the TPSA ≤ 80 Å2 cut-off. It is known that more than 80 % of drugs on the market have an estimated logSw value greater than -4. Thus, solubility filtering was also used to design this Fragment Subset.

Finally, PAINS and in-house developed filtering parameters, such as toxicophore and undesired functionalities, were applied to make up this compound set.

The Life Chemicals Ultimate Fragment Collection comprises nearly 8,800 drug-like fragments. Physicochemical parameters used to create the Ultimate Fragment Library are as follows:




Average Values


150 - 300



-2 - 3



< 80 Å2


Rotatable bonds

≤ 3.0



≤ 3.0



≤ 3.0



≥ -3


Halogens (except F)

≤ 1

≤ 1

S atoms

≤ 1

≤ 1

Ring count

1 - 3

1 - 3

Fused rings

≤ 2

≤ 2

Benzene count

≤ 1

≤ 1


Cherry-picking is available. Please, contact us at orders@lifechemicals.com for any details and quotations.

 Figure 1. Average values for the main physicochemical parameters for the Ultimate Fragment Library compounds

 Ultimate Fragment Library  representative compounds

Figure 2. Representative compounds from Ultimate Fragment Library



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