Design, parallel synthesis, and crystal structures of pyrazinone antithrombotics as selective inhibitors of the tissue factor VIIa complex.
Structure-based drug design (SBDD) and polymer-assisted solution-phase (PASP) library synthesis were used to develop a series of pyrazinone inhibitors of the Tissue Factor/Factor VIIa (TF/VIIa) complex. The crystal structure of a tripeptide-alpha-ketothiazole complexed with TF/VIIa was utilized in a docking experiment to identify the pyrazinone core as a starting scaffold. The pyrazinone core could orient the substituents in the correct spatial arrangement to probe the S1, S2, and S3 pockets of the enzyme. A multistep PASP library synthesis was designed to prepare the substituted pyrazinones varying the P1, P2, and P3 moieties. Hundreds of pyrazinone TF/VIIa inhibitors were prepared and tested in several serine protease enzyme assays involved in the coagulation cascade. The inhibitors exhibited modest activity on TF/VIIa with excellent selectivity over thrombin (IIa) and Factor Xa. The structure-activity relationship of the pyrazinone inhibitors will be discussed and X-ray crystal structures of selected compounds complexed with the TF/VIIa enzyme will be described. This study ultimately led to the synthesis of compound 34, which exhibited 16 nM (IC50) activity on TF/VIIa with >6250 x selectivity vs Factor Xa and thrombin. This potent and highly selective inhibitor of TF/VIIa was chosen for preclinical, intravenous proof-of-concept studies to demonstrate the separation between antithrombotic efficacy and bleeding side effects in a nonhuman primate model of electrolytic-induced arterial thrombosis.
Parlow
John J
JJ
Department of Medicinal and Combinatorial Chemistry, Pharmacia Corporation, 800 North Lindbergh Boulevard, St. Louis, Missouri 63167, USA. john.j.parlow@pfizer.com
Case
Brenda L
BL
Dice
Thomas A
TA
Fenton
Ricky L
RL
Hayes
Michael J
MJ
Jones
Darin E
DE
Neumann
William L
WL
Wood
Rhonda S
RS
Lachance
Rhonda M
RM
Girard
Thomas J
TJ
Nicholson
Nancy S
NS
Clare
Michael
M
Stegeman
Roderick A
RA
Stevens
Anna M
AM
Stallings
William C
WC
Kurumbail
Ravi G
RG
South
Michael S
MS
D000990:Antithrombin III / Q000494:pharmacology; D001665:Binding Sites; D020650:Combinatorial Chemistry Techniques / Q000379:methods; D018360:Crystallography, X-Ray; D015195:Drug Design; D015942:Factor VIIa / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics; D005343:Fibrinolytic Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D020128:Inhibitory Concentration 50; D008958:Models, Molecular; D011719:Pyrazines / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology; D013329:Structure-Activity Relationship; D013844:Thiazoles / Q000737:chemistry / Q000494:pharmacology; D013917:Thrombin / Q000037:antagonists & inhibitors; D013925:Thromboplastin / Q000037:antagonists & inhibitors* / Q000737:chemistry
D005343:Fibrinolytic Agents; D011719:Pyrazines; D011994:Recombinant Proteins; D015842:Serine Proteinase Inhibitors; D013844:Thiazoles; D000990:Antithrombin III; D013925:Thromboplastin; D015942:Factor VIIa; D013917:Thrombin