No abstract

Structure-activity relationships within a series of highly potent 2-carboxyindole-based factor Xa inhibitors incorporating a neutral P1 ligand are described with particular emphasis on the structural requirements for addressing subpockets of the factor Xa enzyme. Interactions with the subpockets were probed by systematic substitution of the 2-carboxyindole scaffold, in combination with privileged P1 and P4 substituents. Combining the most favorable substituents at the indole nucleus led to the discovery of a remarkably potent factor Xa inhibitor displaying a K(i) value of 0.07 nM. X-ray crystallography of inhibitors bound to factor Xa revealed substituent-dependent switching of the inhibitor binding mode and provided a rationale for the SAR obtained. These results underscore the key role played by the P1 ligand not only in determining the binding affinity of the inhibitor by direct interaction but also in modifying the binding mode of the whole scaffold, resulting in a nonlinear SAR.

Attraktives Chlor: Nichtkovalente Wechselwirkungen zwischen Chlor‐ oder Brom‐Atomen und aromatischen Ringen in Proteinen bieten einen neuen Ansatzpunkt für die Beeinflussung der molekularen Erkennung. Die Einführung dieser Substituenten an spezifischen Positionen zweier Faktor‐Xa‐Inhibitoren erhöht deren freie Bindungsenergie durch die Wechselwirkung mit einer Tyrosineinheit. Das allgemeine Vorkommen dieses Strukturmotivs wird anhand zahlreicher Kristallstukturen und quantenchemischer Rechnungen belegt (siehe Bild).

Attractive chlorine: Noncovalent interactions between chlorine or bromine atoms and aromatic rings in proteins open up a new method for the manipulation of molecular recognition. Substitution at distinct positions of two factor Xa inhibitors improves the free energy of binding by interaction with a tyrosine unit. The generality of this motif was underscored by multiple crystal structures as well as high-level quantum chemical calculations (see picture).

In this Perspective, recent advances and challenges in the development of GPR119 agonists as new oral antidiabetic drugs will be discussed. Such agonists are expected to exhibit a low risk to induce hypoglycemia as well as to have a beneficial impact on body weight. Many pharmaceutical companies have been active in the search for GPR119 agonists, making it a highly competitive area in the industrial environment. Several GPR119 agonists have been entered into clinical studies, but many have failed either in phase I or II and none has progressed beyond phase II. Herein we describe the strategies chosen by the different medicinal chemistry teams in academia and the pharmaceutical industry to improve potency, physicochemical properties, pharmacokinetics, and the safety profile of GPR119 agonists in the discovery phase in order to improve the odds for successful development.