Identification, synthesis, and biological evaluation of 6-[(6R)-2-(4-fluorophenyl)-6-(hydroxymethyl)-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrimidin-3-yl]-2-(2-methylphenyl)pyridazin-3(2H)-one (AS1940477), a potent p38 MAP kinase inhibitor.
Several p38 MAPK inhibitors have been shown to effectively block the production of cytokines such as IL-1β, TNFα, and IL-6. Inhibitors of p38 MAP kinase therefore have significant therapeutic potential for the treatment of autoimmune disease. Compound 2a was identified as a potent TNFα production inhibitor in vitro but suffered from poor oral bioavailability. Structural modification of 2a led to the discovery of tetrahydropyrazolopyrimidine derivatives, exemplified by compound 3, with an improved pharmacokinetic profile. We found that blocking metabolism at the methyl group of the amine and constructing the tetrahydropyrimidine core were important to obtaining compounds with good biological profiles and oral bioavailability. Pursuing the structure-activity relationships of this series led to the discovery of AS1940477 (3f), with excellent cellular activity and a favorable pharmacokinetic profile. This compound represents a highly potent inhibitor of p38 MAP kinase with regard to in vivo activity in an adjuvant-induced arthritis model.
Drug Discovery Research, Astellas Pharma Inc., 21, Miyukigaoka, Tsukuba-shi, Ibaraki 305-8585, Japan. toru.asano@astellas.com
Toru
T
Asano
Hitoshi
H
Yamazaki
Chiyoshi
C
Kasahara
Hirokazu
H
Kubota
Toru
T
Kontani
Yu
Y
Harayama
Kazuki
K
Ohno
Hidekazu
H
Mizuhara
Masaharu
M
Yokomoto
Keiji
K
Misumi
Tomohiko
T
Kinoshita
Mitsuaki
M
Ohta
Makoto
M
Takeuchi
D001682:Biological Availability; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D047428:Protein Kinase Inhibitors / Q000138:chemical synthesis / Q000493:pharmacokinetics / Q000494:pharmacology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors*
D047428:Protein Kinase Inhibitors; D048051:p38 Mitogen-Activated Protein Kinases