Imaeda Yasuhiro, Miyawaki Toshio, Sakamoto Hiroki, Itoh Fumio, Konishi Noriko, Hiroe Katsuhiko, Kawamura Masaki, Tanaka Toshimasa, Kubo Keiji
Pharmaceutical Research Division, Takeda Pharmaceutical Co., Ltd, 2-17-85, Jusohonmachi, Yodogawa-ku, Osaka 532-8686, Japan.
Bioorg Med Chem. 2008 Mar 1;16(5):2243-60. doi: 10.1016/j.bmc.2007.11.073. Epub 2007 Dec 3.
Factor Xa (FXa) is a trypsin-like serine protease involved in the coagulation cascade and has received great interest as a potential target for the development of new antithrombotic agents. Most of amidine-type FXa inhibitors reported have been found to show extremely poor oral bioavailability. Compound 1 is one of the first reported non-amidine type FXa inhibitors. To discover novel and orally active FXa inhibitors, we investigated flexible linear linkers between the 6-chloronaphthalene ring and the 1-(pyridin-4-yl)piperidine moiety of 1 and found the orally active sulfonylalkylamide 2f with an FXa IC(50) of 0.05 microM, comparable with that of 1. Further modification to reduce the CYP3A4 inhibitory activity of 2f resulted in the potent, selective, and orally active 2-methylpyridine analogue 2s (FXa IC(50) of 0.061 microM), for which the liability of CYP3A4 inhibition was significantly weakened compared to 2f. Compound 2s also showed long lasting anticoagulant activity in cynomolgus monkeys.
