RESUMEN
A novel 1,3,5-trisubstituted benzamide thrombin inhibitor template was designed via hybridization of a known aminopyridinoneacetamide and a known 1,3,5-trisubstituted phenyl ether. Optimization of this lead afforded a novel potent series of biaryl 1,3,5-trisubstituted benzenes with excellent functional anticoagulant potency.
Asunto(s)
Antitrombinas/síntesis química , Benceno/síntesis química , Diseño de Fármacos , Trombina/antagonistas & inhibidores , Antitrombinas/química , Antitrombinas/farmacología , Benceno/química , Benceno/farmacología , Humanos , Modelos Moleculares , Estructura Molecular , Relación Estructura-ActividadRESUMEN
Optimization of a previously reported thrombin inhibitor, 9-hydroxy-9-fluorenylcarbonyl-l-prolyl-trans-4-aminocyclohexylmethylamide (1), by replacing the aminocyclohexyl P1 group provided a new lead structure, 9-hydroxy-9-fluorenylcarbonyl-l-prolyl-2-aminomethyl-5-chlorobenzylamide (2), with improved potency (K(i) = 0.49 nM for human thrombin, 2x APTT = 0.37 microM in human plasma) and pharmacokinetic properties (F = 39%, iv T(1/2) = 13 h in dogs). An effective strategy for reducing plasma protein binding of 2 and improving efficacy in an in vivo thrombosis model in rats was to replace the lipophilic fluorenyl group in P3 with an azafluorenyl group. Systematic investigation of all possible azafluorenyl P3 isomers and azafluorenyl-N-oxide analogues of 2 led to the identification of an optimal compound, 3-aza-9-hydroxyfluoren-9(R)-ylcarbonyl-l-prolyl-2-aminomethyl-5-chlorobenzylamide (19b), with high potency (K(i) = 0.40 nM, 2x APTT = 0.18 microM), excellent pharmacokinetic properties (F = 55%, T(1/2) = 14 h in dogs), and complete efficacy in the in vivo thrombosis model in rats (inhibition of FeCl(3)-induced vessel occlusions in six of six rats receiving an intravenous infusion of 10 microg/kg/min of 19b). The stereochemistry of the azafluorenyl group in 19b was determined by X-ray crystallographic analysis of its N-oxide derivative (23b) bound in the active site of human thrombin.
Asunto(s)
Fluorenos/síntesis química , Prolina/análogos & derivados , Prolina/síntesis química , Trombina/antagonistas & inhibidores , Administración Oral , Animales , Disponibilidad Biológica , Proteínas Sanguíneas/metabolismo , Cristalografía por Rayos X , Perros , Fluorenos/química , Fluorenos/farmacología , Semivida , Humanos , Técnicas In Vitro , Macaca mulatta , Masculino , Microsomas Hepáticos/metabolismo , Modelos Moleculares , Prolina/química , Prolina/farmacología , Unión Proteica , Ratas , Ratas Sprague-Dawley , Estereoisomerismo , Relación Estructura-ActividadRESUMEN
Modification of lead compound 1 by reducing lipophilicity in the P3 group produced a series of low molecular weight thrombin inhibitors with excellent potency in functional assays, metabolic stability, and oral bioavailability. These modifications led to the identification of two optimized compounds, 14 and 16.
Asunto(s)
Antitrombinas/farmacología , Administración Oral , Antitrombinas/administración & dosificación , Antitrombinas/farmacocinética , Disponibilidad Biológica , Estabilidad de Medicamentos , Peso MolecularRESUMEN
In an effort to discover potent, clinically useful thrombin inhibitors, a rapid analogue synthetic approach was used to explore the P(1) region. Various benzylamines were coupled to a pyridine/pyrazinone P(2)-P(3) template. One compound with an o-thiadiazole benzylic substitution was found to have a thrombin K(i) of 0.84 nM. A study of ortho-substituted five-membered-ring heterocycles was undertaken and subsequently demonstrated that the o-triazole and tetrazole rings were optimal. Combination of these potent P(1) aryl heterocycles with a variety of P(2)-P(3) groups produced a compound with an extraordinary thrombin inhibitory activity of 1.4 pM. It is hoped that this potency enhancement in P(1) will allow for more diversification in the P(2)-P(3) region to ultimately address additional pharmacological concerns.
