Design, synthesis, and biological activity of non-amidine factor Xa inhibitors containing pyridine N-oxide and 2-carbamoylthiazole units.
Based on the both of results for X-ray studies of tetrahydrothiazolopyridine derivative 1c and FXV673, we synthesized a series of thiazol-5-ylpyridine derivatives containing pyridine N-oxide and 2-carbamoylthiazole units to optimize the S4 binding element. N-Oxidation of thiazol-5-ylpyridine increased the anti-fXa activity more than 10-fold independent on the position of N-oxide. The 4-pyridine N-oxide derivatives 3a and 3d excelled over the tetrahydrothiazolopyridine 1b in potency. 2-Methylpyridine N-oxide 3d exhibited 49-fold selectivity over thrombin. Our modeling study proposed a binding mode that the pyridine N-oxide ring of 3a stuck into the "cation hole" , and the oxide anion of 3a occupied in the almost same space to that of FXV673. From observations of the SAR and modeling studies, we suggested the possibilities that the formation of hydrogen bond with the oxide anion in the "cation hole" and the affinity of cationic pyridine ring to S4 subsite were responsible for increase in anti-fXa activity.
Medicinal Chemistry Research Laboratory, Daiichi Pharmaceutical Co. Ltd, 1-16-13, Kita-Kasai, Edogawa-ku, Tokyo 134-8630, Japan.
Noriyasu
N
Haginoya
Syozo
S
Kobayashi
Satoshi
S
Komoriya
Toshiharu
T
Yoshino
Tsutomu
T
Nagata
Yumiko
Y
Hirokawa
Takayasu
T
Nagahara
D000578:Amidines / Q000138:chemical synthesis / Q000494:pharmacology; D000818:Animals; D001665:Binding Sites / Q000502:physiology; D003497:Cyclic N-Oxides / Q000138:chemical synthesis* / Q000494:pharmacology; D015195:Drug Design; D015951:Factor Xa / Q000378:metabolism; D065427:Factor Xa Inhibitors; D006801:Humans; D008297:Male; D011725:Pyridines / Q000138:chemical synthesis* / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D015842:Serine Proteinase Inhibitors / Q000138:chemical synthesis* / Q000494:pharmacology; D013844:Thiazoles / Q000138:chemical synthesis / Q000494:pharmacology
D000578:Amidines; D003497:Cyclic N-Oxides; D065427:Factor Xa Inhibitors; D011725:Pyridines; D015842:Serine Proteinase Inhibitors; D013844:Thiazoles; D015951:Factor Xa