title: 1,2,3-Thiadiazole substituted pyrazolones as potent KDR/VEGFR-2 kinase inhibitors.
abstract: KDR kinase inhibition is considered to play an important role in regulating angiogenesis, which is vital for the survival and proliferation of tumor cells. Recently we disclosed a structure-based kinase inhibitor design strategy which led to the identification of a new class of VEGFR-2/KDR kinase inhibitors bearing heterocyclic substituted pyrazolones as the core template. Instability in a rat S9 preparation and poor iv PK profiles for most of these inhibitors necessitated exploration of new pyrazolones to identify new analogs with improved metabolic stability. Optimization of the heterocyclic moiety led to the identification of the thiadiazole series of pyrazolones (D) as potent VEGFR-2/KDR kinase inhibitors. SAR modifications, kinase selectivity profiling, and structural elements for improved PK properties were explored. Oral bioavailability up to 29% was achieved in the rat. Modeling results based on the Glide XP docking approach supported our postulation regarding the interaction of the lactam segment of the pyrazolones with the hinge region of the KDR kinase.
authors.affiliation: Cephalon Inc., 145 Brandywine Parkway, West Chester, PA 19380, USA. rtripath@cephalon.com
authors.forename: Rabindranath
authors.initials: R
authors.lastname: Tripathy
authors.forename: Arup
authors.initials: A
authors.lastname: Ghose
authors.forename: Jasbir
authors.initials: J
authors.lastname: Singh
authors.forename: Edward R
authors.initials: ER
authors.lastname: Bacon
authors.forename: Thelma S
authors.initials: TS
authors.lastname: Angeles
authors.forename: Shi X
authors.initials: SX
authors.lastname: Yang
authors.forename: Mark S
authors.initials: MS
authors.lastname: Albom
authors.forename: Lisa D
authors.initials: LD
authors.lastname: Aimone
authors.forename: Joseph L
authors.initials: JL
authors.lastname: Herman
authors.forename: John P
authors.initials: JP
authors.lastname: Mallamo
mesh_terms: D000818:Animals; D001345:Autoradiography; D001682:Biological Availability; D015153:Blotting, Western; D015195:Drug Design; D004791:Enzyme Inhibitors / Q000138:chemical synthesis* / Q000493:pharmacokinetics / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D008958:Models, Molecular; D011480:Protease Inhibitors / Q000138:chemical synthesis / Q000494:pharmacology; D047069:Pyrazolones / Q000138:chemical synthesis* / Q000493:pharmacokinetics / Q000494:pharmacology*; D051381:Rats; D011994:Recombinant Proteins; D013050:Spectrometry, Fluorescence; D013329:Structure-Activity Relationship; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000037:antagonists & inhibitors*
chemical_list: D004791:Enzyme Inhibitors; D011480:Protease Inhibitors; D047069:Pyrazolones; D011994:Recombinant Proteins; D040301:Vascular Endothelial Growth Factor Receptor-2