Finding the perfect spot for fluorine: Improving potency up to 40-fold during a rational fluorine scan of a Bruton's Tyrosine Kinase (BTK) inhibitor scaffold.
Lou, Y., Sweeney, Z.K., Kuglstatter, A., Davis, D., Goldstein, D.M., Han, X., Hong, J., Kocer, B., Kondru, R.K., Litman, R., McIntosh, J., Sarma, K., Suh, J., Taygerly, J., Owens, T.D.(2015) Bioorg Med Chem Lett 25: 367-371
- PubMed: 25466710 
- DOI: https://doi.org/10.1016/j.bmcl.2014.11.030
- Primary Citation of Related Structures:  
4RFY, 4RFZ, 4RG0 - PubMed Abstract: 
A rational fluorine scan based on co-crystal structures was explored to increase the potency of a series of selective BTK inhibitors. While fluorine substitution on a saturated bicyclic ring system yields no apparent benefit, the same operation on an unsaturated bicyclic ring can increase HWB activity by up to 40-fold. Comparison of co-crystal structures of parent molecules and fluorinated counterparts revealed the importance of placing fluorine at the optimal position to achieve favorable interactions with protein side chains.
Organizational Affiliation: 
Hoffmann-La Roche Inc., pRED, Pharma Research & Early Development, Small Molecule Research, Discovery Chemistry, 3431 Hillview Ave, Palo Alto, CA 94304, United States. Electronic address: ylou@nurix-inc.com.