We have developed a novel series of potent and selective factor Xa inhibitors that employ a key 7-fluoroindazolyl moiety. The 7-fluoro group on the indazole scaffold replaces the carbonyl group of an amide that is found in previously reported factor Xa inhibitors. The structure of a factor Xa cocrystal containing 7-fluoroindazole 51a showed the 7-fluoro atom hydrogen-bonding with the N-H of Gly216 (2.9 A) in the peptide backbone. Thus, the 7-fluoroindazolyl moiety not only occupied the same space as the carbonyl group of an amide found in prior factor Xa inhibitors but also maintained a hydrogen bond interaction with the protein's beta-sheet domain. The structure-activity relationship for this series was consistent with this finding, as the factor Xa inhibitory potencies were about 60-fold greater (DeltaDelta G approximately 2.4 kcal/mol) for the 7-fluoroindazoles 25a and 25c versus the corresponding indazoles 25b and 25d. Highly convergent synthesis of these factor Xa inhibitors is also described.
A novel 2,7-disubstituted-pyrrolo[2,1-f][1,2,4]triazine scaffold has been designed as a new kinase inhibitor platform mimicking the bioactive conformation of the well-known diaminopyrimidine motif. The design, synthesis, and validation of this new pyrrolo[2,1-f][1,2,4]triazine scaffold will be described for inhibitors of anaplastic lymphoma kinase (ALK). Importantly, incorporation of appropriate potency and selectivity determinants has led to the discovery of several advanced leads that were orally efficacious in animal models of anaplastic large cell lymphoma (ALCL). A lead inhibitor (30) displaying superior efficacy was identified and in depth in vitro/in vivo characterization will be presented.
The synthesis of a new kinase inhibitor template 2-anilino-7-aryl-pyrrolo[2,1-f][1,2,4]triazine is described which includes a late stage orthogonally reactive key intermediate amenable to rapid diversification as well an optimized in situ triflate displacement to install the C2-aniline. Furthermore, an efficient scalable process approach will be highlighted which begins with tert-butyl carbazate to provide the key N-N bond and generates the pyrrolotriazine core through a stable bromoaldehyde intermediate followed by condensation with ammonium carbonate.
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