In recent years, the first generation of β-secretase (BACE1) inhibitors advanced into clinical development for the treatment of Alzheimer’s disease (AD). However, the alignment of drug-like properties and selectivity remains a major challenge. Herein, we describe the discovery of a novel class of potent, low clearance, CNS penetrant BACE1 inhibitors represented by thioamidine 5. Further profiling suggested that a high fraction of the metabolism (>95%) was due to CYP2D6, increasing the potential risk for victim-based drug–drug interactions (DDI) and variable exposure in the clinic due to the polymorphic nature of this enzyme. To guide future design, we solved crystal structures of CYP2D6 complexes with substrate 5 and its corresponding metabolic product pyrazole 6, which provided insight into the binding mode and movements between substrate/inhibitor complexes. Guided by the BACE1 and CYP2D6 crystal structures, we designed and synthesized analogues with reduced risk for DDI, central efficacy, and improved hERG therapeutic margins.

This paper describes the design and synthesis of a novel series of dual inhibitors of acetyl-CoA carboxylase 1 and 2 (ACC1 and ACC2). Key findings include the discovery of an initial lead that was modestly potent and subsequent medicinal chemistry optimization with a focus on lipophilic efficiency (LipE) to balance overall druglike properties. Free-Wilson methodology provided a clear breakdown of the contributions of specific structural elements to the overall LipE, a rationale for prioritization of virtual compounds for synthesis, and a highly successful prediction of the LipE of the resulting analogues. Further preclinical assays, including in vivo malonyl-CoA reduction in both rat liver (ACC1) and rat muscle (ACC2), identified an advanced analogue that progressed to regulatory toxicity studies.

A practical asymmetric synthesis of (S) 4-ethyl-7,8-dihydro-4-hydroxy-1H-pyrano[3,4-f]indolizine-3,6,10(4H)-trione (1), a versatile intermediate for the synthesis of camptothecin analogs, was developed. Commercially available citrazinic acid is converted in four steps into the 2-chloro-6-methoxypyridine 5. An ortho-directed metalation followed by reaction with a formamide produces an aldehyde with the required 2,3,4,6-substituted pyridine (6) with high regioselectivity. After refunctionalization of the aldehyde, the chloropyridine is converted into an ester by a facile palladium-mediated carbonylation reaction. Wittig reaction and racemic osmylation produce the diol 16 which is resolved by an efficient lipase resolution to an ee > 99%, and a one-pot recycle of the unwanted diol enantiomer was developed. A series of high-yielding oxidation and deprotection steps convert (S)-16 into the pyridone 25, which is then converted into 1 with an ee > 99.6%.

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