RESUMEN
High-throughput screening of a combinatorial library of diamidophenols yielded lead compounds with the ability to inhibit human factor Xa (fXa) at micromolar concentrations (e.g. compound 4, fXa apparent K(ass) = 0.64 x 10(6) L/mol). SAR studies in this novel structural series of fXa inhibitors showed that the phenolic hydroxyl group was not essential for activity. The best activity was found in substituted 1,2-dibenzamidobenzenes in which the phenyl group of one benzoyl group (A-ring) was substituted in the 4-position with relatively small lipophilic or polarizable groups such as methoxy, vinyl, or chloro and the phenyl group of the other benzoyl group (B-ring) was substituted in the 4-position with larger lipophilic groups such as tert-butyl or dimethylamino. The central phenyl ring (C-ring) tolerated a wide variety of substituents, but methoxy, methanesulfonamido, hydroxyl, and carboxyl substitution produced slightly higher levels of activity than other substituents when present in combination with favorable B-ring substitution. Methylation of the amide nitrogen atoms was found to greatly decrease activity. Compound 12 is the highest affinity fXa inhibitor in this group of compounds, having fXa apparent K(ass) = 25.5 x 10(6) L/mol, about 40x more active than the original lead. This lead series does not show potent inhibition of human thrombin. A model for the binding of these ligands to the fXa active site is proposed. The model is consistent with the observed SAR and can serve to guide future SAR studies.
Asunto(s)
Anticoagulantes/síntesis química , Inhibidores Enzimáticos/síntesis química , Inhibidores del Factor Xa , Fenilendiaminas/síntesis química , Sulfonamidas/síntesis química , Trombina/antagonistas & inhibidores , Anticoagulantes/química , Anticoagulantes/metabolismo , Sitios de Unión , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/metabolismo , Factor Xa/química , Factor Xa/metabolismo , Humanos , Modelos Moleculares , Fenilendiaminas/química , Fenilendiaminas/metabolismo , Fenilendiaminas/farmacología , Inhibidores de Serina Proteinasa/síntesis química , Inhibidores de Serina Proteinasa/química , Inhibidores de Serina Proteinasa/metabolismo , Relación Estructura-Actividad , Sulfonamidas/química , Sulfonamidas/metabolismo , Sulfonamidas/farmacología , Trombina/metabolismoRESUMEN
To enhance the potency of 1,2-dibenzamidobenzene-derived inhibitors of factor Xa (fXa), an amidine substituent was incorporated on one of the benzoyl side chains to interact with Asp189 in the S1 specificity pocket. Lead molecule 1 was docked into the active site of fXa to facilitate inhibitor design. Subsequently, iterative SAR studies and molecular modeling led to a 1000-fold increase in fXa affinity and a refined model of the new inhibitors in the fXa active site. Strong support for the computational model was achieved through the acquisition of an X-ray crystal structure using thrombin as a surrogate protein. The amidines in this series show high levels of selectivity for the inhibition of fXa relative to other trypsin-like serine proteases. Furthermore, the fXa affinity of compounds in this series (K(ass) = 50-500 x 10(6) L/mol) translates effectively into both anticoagulant activity in vitro and antithrombotic activity in vivo.
Asunto(s)
Amidinas/síntesis química , Anticoagulantes/síntesis química , Inhibidores Enzimáticos/síntesis química , Inhibidores del Factor Xa , Fibrinolíticos/síntesis química , Amidinas/química , Amidinas/metabolismo , Amidinas/farmacología , Animales , Anticoagulantes/química , Anticoagulantes/metabolismo , Anticoagulantes/farmacología , Sitios de Unión , Cristalografía por Rayos X , Perros , Diseño de Fármacos , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/metabolismo , Inhibidores Enzimáticos/farmacología , Factor Xa/química , Factor Xa/metabolismo , Fibrinolíticos/química , Fibrinolíticos/metabolismo , Fibrinolíticos/farmacología , Humanos , Técnicas In Vitro , Masculino , Modelos Moleculares , Tiempo de Protrombina , Conejos , Ratas , Ratas Sprague-Dawley , Relación Estructura-Actividad , Trombina/química , Trombina/metabolismo , Trombosis/tratamiento farmacológicoRESUMEN
Modeling of neutral or mildly basic functional groups in the S1 site of thrombin led to the targeting of imidazole as a S1 binding element and correctly predicted the optimal chain length for connecting this group with the S2 and S3 binding elements. Derivatives of 4-(3-aminopropyl)-imidazole can be selective inhibitors of thrombin demonstrating potent anticoagulant activity.
Asunto(s)
Antitrombinas/síntesis química , Imidazoles/metabolismo , Péptidos/síntesis química , Antitrombinas/química , Antitrombinas/farmacología , Sitios de Unión , Cristalografía por Rayos X , Diseño de Fármacos , Humanos , Modelos Moleculares , Péptidos/química , Péptidos/farmacologíaRESUMEN
A series of sulfonimidamide analogs of the oncolytic diarylsulfonylureas was synthesized and evaluated for (1) in vitro cytotoxicity against CEM cells, (2) in vivo antitumor activity against subaxillary implanted 6C3HED lymphosarcoma, and (3) metabolic breakdown to the o-sulfate of p-chloroaniline. The separated enantiomers of one sulfonimidamide analog displayed very different activities in the in vivo screening model. In general, several analogs demonstrated excellent growth inhibitory activity in the 6C3HED model when dosed orally or intraperitoneally. A correlative structure-activity relationship to the oncolytic sulfonylureas was not apparent.