Alexander V. Mayweg

β-Secretase (BACE1) Inhibitors with High in Vivo Efficacy Suitable for Clinical Evaluation in Alzheimer’s Disease

An extensive fluorine scan of 1,3-oxazines revealed the power of fluorine(s) to lower the pKa and thereby dramatically change the pharmacological profile of this class of BACE1 inhibitors. The CF3 substituted oxazine 89, a potent and highly brain penetrant BACE1 inhibitor, was able to reduce significantly CSF Aβ40 and 42 in rats at oral doses as low as 1 mg/kg. The effect was long lasting, showing a significant reduction of Aβ40 and 42 even after 24 h. In contrast to 89, compound 1b lacking the CF3 group was virtually inactive in vivo.

Benzodioxoles: Novel Cannabinoid-1 Receptor Inverse Agonists for the Treatment of Obesity

The application of the evolutionary fragment-based de novo design tool TOPology Assigning System (TOPAS), starting from a known CB1R (CB-1 receptor) ligand, followed by further refinement principles, including pharmacophore compliance, chemical tractability, and drug likeness, allowed the identification of benzodioxoles as a novel CB1R inverse agonist series. Extensive multidimensional optimization was rewarded by the identification of promising lead compounds, showing in vivo activity. These compounds reversed the CP-55940-induced hypothermia in Naval Medical Research Institute (NMRI) mice and reduced body-weight gain, as well as fat mass, in diet-induced obese Sprague-Dawley rats. Herein, we disclose the tools and strategies that were employed for rapid hit identification, synthesis and generation of structure-activity relationships, ultimately leading to the identification of (+)-[( R)-2-(2,4-dichloride-phenyl)-6-fluoro-2-(4-fluoro-phenyl)-benzo[1,3]dioxol-5-yl]-morpholin-4-yl-methanone ( R)-14g . Biochemical, pharmacokinetic, and pharmacodynamic characteristics of ( R)-14g are discussed.

BACE1 inhibitors: a head group scan on a series of amides.

A series of amides bearing a variety of amidine head groups was investigated as BACE1 inhibitors with respect to inhibitory activity in a BACE1 enzyme as well as a cell-based assay. Determination of their basicity as well as their properties as substrates of P-glycoprotein revealed that a 2-amino-1,3-oxazine head group would be a suitable starting point for further development of brain penetrating compounds for potential Alzheimers disease treatment.

Design and Synthesis of Orally Bioavailable 4-Methyl Heteroaryldihydropyrimidine Based Hepatitis B Virus (HBV) Capsid Inhibitors

Targeting the capsid protein of hepatitis B virus (HBV) and thus interrupting normal capsid formation have been an attractive approach to block the replication of HBV viruses. We carried out multidimensional structural optimizations based on the heteroaryldihydropyrimidine (HAP) analogue Bay41-4109 (1) and identified a novel series of HBV capsid inhibitors that demonstrated promising cellular selectivity indexes, metabolic stabilities, and in vitro safety profiles. Herein we disclose the design, synthesis, structure-activity relationship (SAR), cocrystal structure in complex with HBV capsid proteins and in vivo pharmacological study of the 4-methyl HAP analogues. In particular, the (2S,4S)-4,4-difluoroproline substituted analogue 34a demonstrated high oral bioavailability and liver exposure and achieved over 2 log viral load reduction in a hydrodynamic injected (HDI) HBV mouse model.

Transannular, decarboxylative Claisen rearrangement reactions for the synthesis of sulfur-substituted vinylcyclopropanes

Unsaturated epsilon-lactones bearing an alpha-arylsulfonyl or alpha-arylsulfoximinyl substituent undergo stereoselective transannular, decarboxylative Claisen rearrangement to give substituted vinylcyclopropanes.

ROCK: the Roche medicinal chemistry knowledge application – design, use and impact

Medicinal chemistry is a complex science that lies at the interface of many fields of research and at the very heart of drug discovery, with property relationships based on chemical structure at its core. It is clear that the effective capture and dissemination of medicinal chemistry knowledge and experience will be a key differentiator among pharmaceutical organizations and crucial for the future success in delivering effective and safe drug candidates. Therefore, in 2005 we developed ROCK (Roche medicinal chemistry knowledge), an internal user-friendly and peer-reviewed Wiki-like application to capture, browse and search tacit knowledge, key discoveries and property effects related to chemical structure, which is used as a primary source for addressing challenges faced in drug design.

Discovery of 4-Aryl-5,6,7,8-tetrahydroisoquinolines as Potent, Selective, and Orally Active Aldosterone Synthase (CYP11B2) Inhibitors: In Vivo Evaluation in Rodents and Cynomolgus Monkeys.

Inappropriately high levels of aldosterone are associated with many serious medical conditions, including renal and cardiac failure. A focused screen hit has been optimized into a potent and selective aldosterone synthase (CYP11B2) inhibitor with in vitro activity against rat, mouse, human, and cynomolgus monkey enzymes, showing a selectivity factor of 160 against cytochrome CYP11B1 in the last species. The novel tetrahydroisoquinoline compound (+)-(R)-6 selectively reduced aldosterone plasma levels in vivo in a dose-dependent manner in db/db mice and cynomolgus monkeys. The selectivity against CYP11B1 as predicted by cellular inhibition data and free plasma fraction translated well to Synacthen challenged cynomolgus monkeys up to a dose of 0.1 mg kg(-1). This compound, displaying good in vivo potency and selectivity in mice and monkeys, is ideally suited to perform mechanistic studies in relevant rodent models and to provide the information necessary for translation to non-human primates and ultimately to man.

Discovery and Pre-Clinical Characterization of Third-Generation 4-H Heteroaryldihydropyrimidine (HAP) Analogues as Hepatitis B Virus (HBV) Capsid Inhibitors

Described herein are the discovery and structure-activity relationship (SAR) studies of the third-generation 4-H heteroaryldihydropyrimidines (4-H HAPs) featuring the introduction of a C6 carboxyl group as novel HBV capsid inhibitors. This new series of 4-H HAPs showed improved anti-HBV activity and better drug-like properties compared to the first- and second-generation 4-H HAPs. X-ray crystallographic study of analogue 12 (HAP_R01) with Cp149 Y132A mutant hexamer clearly elucidated the role of C6 carboxyl group played for the increased binding affinity, which formed strong hydrogen bonding interactions with capsid protein and coordinated waters. The representative analogue 10 (HAP_R10) was extensively characterized in vitro (ADMET) and in vivo (mouse PK and PD) and subsequently selected for further development as oral anti-HBV infection agent.

Discovery of potent and selective CDK8 inhibitors through FBDD approach

A fragment library screen was carried out to identify starting points for novel CDK8 inhibitors. Optimization of a fragment hit guided by co-crystal structures led to identification of a novel series of potent CDK8 inhibitors which are highly ligand efficient, kinase selective and cellular active. Compound 16 was progressed to a mouse pharmacokinetic study and showed good oral bioavailability.

Chapter Seventeen – Novel Therapeutics in Discovery and Development for Treatment of Chronic HBV Infection

Abstract Hepatitis B virus (HBV) chronic infection represents a major worldwide public health threat leading to cirrhosis and hepatocellular carcinoma. Current treatments for chronic HBV infection include interferon-α and nucleos(t)ides such as lamivudine, telbivudine, adefovir, entecavir, and tenofovir. Unfortunately, none of these therapies offer a satisfactory clinical cure rate. Hence, there remains an unmet medical need for novel and more effective drugs for treatment of HBV infection. Recently, several classes of naturally occurring and synthetic nonnucleoside small molecule HBV inhibitors have been discovered. This review captures important progress on this front in terms of the structural class, mechanism of action, and biological activities. It is conceivable that some of these discoveries might eventually lead to better cure rate of the chronic HBV infection.