Discovery of AM-6494: A Potent and Orally Efficacious ß-Site Amyloid Precursor Protein Cleaving Enzyme 1 (BACE1) Inhibitor with in Vivo Selectivity over BACE2.

ß-Site amyloid precursor protein cleaving enzyme 1 (BACE1) is an aspartyl protease that plays a key role in the production of amyloid ß (Aß) in the brain and has been extensively pursued as a target for the treatment of Alzheimer's disease (AD). BACE2, an aspartyl protease that is structurally related to BACE1, has been recently reported to be involved in melanosome maturation and pigmentation. Herein, we describe the development of a series of cyclopropylthiazines as potent and orally efficacious BACE1 inhibitors. Lead optimization led to the identification of 20, a molecule with biochemical IC50 BACE2/BACE1 ratio of 47. Administration of 20 resulted in no skin/fur color change in a 13-day mouse hypopigmentation study and demonstrated robust and sustained reduction of CSF and brain Aß40 levels in rat and monkey pharmacodynamic models. On the basis of a compelling data package, 20 (AM-6494) was advanced to preclinical development.

Optimization of 3-Pyrimidin-4-yl-oxazolidin-2-ones as Orally Bioavailable and Brain Penetrant Mutant IDH1 Inhibitors.

Mutant isocitrate dehydrogenase 1 (IDH1) is an attractive therapeutic target for the treatment of various cancers such as AML, glioma, and glioblastoma. We have evaluated 3-pyrimidin-4-yl-oxazolidin-2-ones as mutant IDH1 inhibitors that bind to an allosteric, induced pocket of IDH1R132H. This Letter describes SAR exploration focused on improving both the in vitro and in vivo metabolic stability of the compounds, leading to the identification of 19 as a potent and selective mutant IDH1 inhibitor that has demonstrated brain penetration and excellent oral bioavailability in rodents. In a preclinical patient-derived IDH1 mutant xenograft tumor model study, 19 efficiently inhibited the production of the biomarker 2-HG.

Discovery and Evaluation of Clinical Candidate IDH305, a Brain Penetrant Mutant IDH1 Inhibitor.

Inhibition of mutant IDH1 is being evaluated clinically as a promising treatment option for various cancers with hotspot mutation at Arg132. Having identified an allosteric, induced pocket of IDH1R132H, we have explored 3-pyrimidin-4-yl-oxazolidin-2-ones as mutant IDH1 inhibitors for in vivo modulation of 2-HG production and potential brain penetration. We report here optimization efforts toward the identification of clinical candidate IDH305 (13), a potent and selective mutant IDH1 inhibitor that has demonstrated brain exposure in rodents. Preclinical characterization of this compound exhibited in vivo correlation of 2-HG reduction and efficacy in a patient-derived IDH1 mutant xenograft tumor model. IDH305 (13) has progressed into human clinical trials for the treatment of cancers with IDH1 mutation.

Asymmetric construction of rings A-D of daphnicyclidin-type alkaloids.

The aza-Cope-Mannich reaction and ring-closing metathesis are key steps in the assembly of intermediates containing rings A-D of Daphniphyllum alkaloids of the daphnicyclidin type such as daphnipaxinin and oldhamine A.

1-Naphthyl and 4-indolyl arylalkylamines as selective monoamine reuptake inhibitors.

A series of enantiomerically pure 1-naphthyl and 4-indolyl arylalkylamines were prepared and evaluated for their binding affinities to the monoamine transporters. The two series of enantiomers displayed considerable differences in binding selectivity between the monoamine transporters, leading to the design of (S)-4-(3,4-dichlorophenyl)-4-(1H-indol-4-yl)-N-methylbutan-1-amine as a potent inhibitor for the dopamine and serotonin transporters.

One-pot synthesis of highly functionalized pyridines via a rhodium carbenoid induced ring expansion of isoxazoles.

A concise one-pot synthesis of highly functionalized pyridines has been developed. The first step in the reaction sequence is the formal insertion of rhodium vinylcarbenoids across the N-O bond of isoxazoles. Upon heating, the insertion products undergo a rearrangement to give 1,4-dihydropyridines. DDQ oxidation then affords the corresponding pyridines in 31-84% yield. The process has proven general with a range of carbenoid and isoxazole components and represents a unique disconnection strategy for the synthesis of functionalized pyridines.

Catalytic C-H functionalization by metal carbenoid and nitrenoid insertion.

Novel reactions that can selectively functionalize carbon-hydrogen bonds are of intense interest to the chemical community because they offer new strategic approaches for synthesis. A very promising 'carbon-hydrogen functionalization' method involves the insertion of metal carbenes and nitrenes into C-H bonds. This area has experienced considerable growth in the past decade, particularly in the area of enantioselective intermolecular reactions. Here we discuss several facets of these kinds of C-H functionalization reactions and provide a perspective on how this methodology has affected the synthesis of complex natural products and potential pharmaceutical agents.

Efficient route to 4H-1,3-oxazines through ring expansion of isoxazoles by rhodium carbenoids.

Studies related to the total synthesis of elisabethin C led to the discovery of a rhodium-catalyzed cascade sequence involving isoxazole ring expansion and a [4 + 3] cycloaddition. The scope of the isoxazole ring expansion was explored, resulting in the synthesis of a range of 4H-1,3-oxazines in 47-96% yield.

C-H activation as a strategic reaction: enantioselective synthesis of 4-substituted indoles.

A method is described for the asymmetric synthesis of 4-substituted indoles from the Rh2(S-DOSP)4-catalyzed decomposition of vinyldiazoacetates in the presence of N-Boc-4-acetoxy-6,7-dihydroindole. The reaction proceeds via a combined C-H activation/Cope rearrangement-elimination mechanism resulting in good yields and very high asymmetric induction.