ABSTRACT
The in silico construction of a PDGFRß kinase homology model and ensuing medicinal chemistry guided by molecular modeling, led to the identification of potent, small molecule inhibitors of PDGFR. Subsequent exploration of structure-activity relationships (SAR) led to the incorporation of a constrained secondary amine to enhance selectivity. Further refinements led to the integration of a fluorine substituted piperidine, which resulted in significant reduction of P-glycoprotein (Pgp) mediated efflux and improved bioavailability. Compound 28 displayed oral exposure in rodents and had a pronounced effect in a pharmacokinetic-pharmacodynamic (PKPD) assay.
ABSTRACT
The synthesis and biological evaluation of non-oxime pyrazole based B-Raf inhibitors is reported. Several oxime replacements have been prepared and have shown excellent enzyme activity. Further optimization of fused pyrazole 2a led to compound 38, a selective and potent B-Raf inhibitor.
Subject(s)
Enzyme Inhibitors/pharmacology , Proto-Oncogene Proteins B-raf/antagonists & inhibitors , Pyrazoles/chemical synthesis , Pyrazoles/pharmacology , Animals , Crystallography, X-Ray , Dose-Response Relationship, Drug , Enzyme Activation/drug effects , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/chemistry , Inhibitory Concentration 50 , Mice , Molecular Structure , Oximes/chemistry , Pyrazoles/chemistryABSTRACT
Herein we describe a novel pyrazole-based class of ATP competitive B-Raf inhibitors. These inhibitors exhibit both excellent cellular potency and striking B-Raf selectivity. A subset of these inhibitors has demonstrated the ability to inhibit downstream ERK phosphorylation in LOX tumors from mouse xenograft studies.
Subject(s)
Chemistry, Pharmaceutical/methods , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/pharmacology , Proto-Oncogene Proteins B-raf/antagonists & inhibitors , Proto-Oncogene Proteins B-raf/chemistry , Pyrazoles/chemistry , raf Kinases/antagonists & inhibitors , raf Kinases/chemistry , Animals , Cell Line, Tumor , Crystallography, X-Ray/methods , Drug Design , Humans , Inhibitory Concentration 50 , Mice , Models, Chemical , Neoplasm Transplantation , PhosphorylationABSTRACT
Combinatorial small molecule growth algorithm was used to design inhibitors for human carbonic anhydrase II. Two enantiomeric candidate molecules were predicted to bind with high potency (with R isomer binding stronger than S), but in two distinct conformations. The experiments verified that computational predictions concerning the binding affinities and the binding modes were correct for both isomers. The designed R isomer is the best-known inhibitor (K(d) approximately 30 pM) of human carbonic anhydrase II.
Subject(s)
Carbonic Anhydrase II/chemistry , Algorithms , Amino Acid Sequence , Carbonic Anhydrase II/metabolism , Combinatorial Chemistry Techniques/methods , Humans , Ligands , Microchemistry/methods , Models, Molecular , Protein ConformationABSTRACT
Remarkable selectivity is exhibited in the photooxidation of 20-methoxychlorin methyl ester (1) to exclusively yield the C1-C20 bond cleaved product 2. This selectivity lends strong support to the hypothesis that a hydroxy or equivalent group at C20 directs the C1-C20 bond cleavage that transforms chlorophylls into krill and dinoflagellate luciferins.
