No abstract

The one-step aza-Darzens reaction of sulfinimines 2 with lithium R-bromoenolates readily affords diversely substituted cis and trans N-sulfinylaziridine 2-carboxylate esters 3 and 7 in good yield and excellent diastereoselectivity. Higher yields, but lower de's, result when a mixture of the R-bromo ester and 2 are treated with base. The N-sulfinyl group is transformed, nearly quantitatively, without ring opening, into the N-tosyl activating group by oxidation with m-CPBA. Selective removal of the N-sulfinyl group in aziridines 3a and 3h with TFA/H 2 O affords 1H-aziridines 21 which are difficult to prepared by other means. However, C(3) activated azirines such as 3b undergo ringopening under these conditions. Alternatively, the N-sulfinyl group, even in C(3)-activated aziridines, was selectively and efficiently removed by treatment of the aziridine with 2 equiv of MeMgBr.

Factor XIa (FXIa) is an enzyme in the coagulation cascade thought to amplify thrombin generation but has a limited role in hemostasis. From preclinical models and human genetics, an inhibitor of FXIa has the potential to be an antithrombotic agent with superior efficacy and safety. Reversible and irreversible inhibitors of FXIa have demonstrated excellent antithrombotic efficacy without increased bleeding time in animal models (WeitzJ. I.ChanN. C. Weitz, J. I. Chan, N. C. Arterioscler. Thromb. Vasc. Biol.201939712). Herein, we report the discovery of a novel series of macrocyclic FXIa inhibitors containing a pyrazole P2′ moiety. Optimization of the series for (pharmacokinetic) PK properties, free fraction, and solubility resulted in the identification of milvexian (BMS-986177/JNJ-70033093, 17, FXIa K i = 0.11 nM) as a clinical candidate for the prevention and treatment of thromboembolic disorders, suitable for oral administration.

A novel series of macrocyclic FXIa inhibitors was designed based on our lead acyclic phenyl imidazole chemotype. Our initial macrocycles, which were double-digit nanomolar FXIa inhibitors, were further optimized with assistance from utilization of structure-based drug design and ligand bound X-ray crystal structures. This effort resulted in the discovery of a macrocyclic amide linker which was found to form a key hydrogen bond with the carbonyl of Leu41 in the FXIa active site, resulting in potent FXIa inhibitors. The macrocyclic FXIa series, exemplified by compound 16, had a FXIa K = 0.16 nM with potent anticoagulant activity in an in vitro clotting assay (aPTT EC = 0.27 μM) and excellent selectivity against the relevant blood coagulation enzymes.