Serge Maria Aloysius Pieters

New 2-substituted 1,2,3,4-tetrahydrobenzofuro[3,2-c]pyridine having highly active and potent central α2-antagonistic activity as potential antidepressants

The synthesis and biological activity of a series of benzofuro[3,2-c]pyridines and a benzothieno[3,2-c]pyridine are described. These compounds exhibit high affinity for the alpha 2-adrenoceptor, with high selectivity versus the alpha 1-receptor. Compound 1 also shows potent in vivo central activity and has been selected for further biological and clinical evaluation.

Design and Synthesis of a Novel Series of Bicyclic Heterocycles As Potent γ-Secretase Modulators

The design and the synthesis of several chemical subclasses of imidazole containing γ-secretase modulators (GSMs) is described. Conformational restriction of pyridone 4 into bicyclic pyridone isosteres has led to compounds with high in vitro and in vivo potency. This has resulted in the identification of benzimidazole 44a as a GSM with low nanomolar potency in vitro. In mouse, rat, and dog, this compound displayed the typical γ-secretase modulatory profile by lowering Aβ42 and Aβ40 levels combined with an especially pronounced increase in Aβ38 and Aβ37 levels while leaving the total levels of amyloid peptides unchanged.

Synthesis and Pharmacological Characterization of Two Novel, Brain Penetrating P2X7 Antagonists

The synthesis and preclinical characterization of two novel, brain penetrating P2X7 compounds will be described. Both compounds are shown to be high potency P2X7 antagonists in human, rat, and mouse cell lines and both were shown to have high brain concentrations and robust receptor occupancy in rat. Compound 7 is of particular interest as a probe compound for the preclinical assessment of P2X7 blockade in animal models of neuro-inflammation.

Anilinotriazoles as potent gamma secretase modulators.

The design and synthesis of a novel series of potent gamma secretase modulators is described. Exploration of various spacer groups between the triazole ring and the aromatic appendix in 2 has led to anilinotriazole 28, which combined high in vitro and in vivo potency with an acceptable drug-like profile.

Novel Pyrimidine Toll-like Receptor 7 and 8 Dual Agonists to Treat Hepatitis B Virus

Toll-like receptor (TLR) 7 and 8 agonists can potentially be used in the treatment of viral infections and are particularly promising for chronic hepatitis B virus (HBV) infection. An internal screening effort identified a pyrimidine Toll-like receptor 7 and 8 dual agonist. This provided a novel alternative over the previously reported adenine and pteridone type of agonists. Structure-activity relationship, lead optimization, in silico docking, pharmacokinetics, and demonstration of ex vivo and in vivo cytokine production of the lead compound are presented.

Discovery of selective 2,4-diaminoquinazoline toll-like receptor 7 (TLR 7) agonists

The discovery of a novel series of highly potent quinazoline TLR 7/8 agonists is described. The synthesis and structure-activity relationship is presented. Structural requirements and optimization of this series toward TLR 7 selectivity afforded the potent agonist 48. Pharmacokinetic and pharmacodynamic studies highlighted 48 as an orally available endogenous interferon (IFN-α) inducer in mice.

Identification and Optimization of Pyrrolo[3,2- d ]pyrimidine Toll-like Receptor 7 (TLR7) Selective Agonists for the Treatment of Hepatitis B

Pyrrolo[3,2-d]pyrimidines were identified as a new series of potent and selective TLR7 agonists. Compounds were optimized for their activity and selectivity over TLR8. This presents an advantage over recently described scaffolds that have residual TLR8 activity, which may be detrimental to the tolerability of the candidate drug. Oral administration of the lead compound 54 effectively induced a transient interferon stimulated gene (ISG) response in mice and cynomolgus monkeys. We aimed for a high first pass effect, limiting cytokine induction systemically, and demonstrated the potential for the immunotherapy of viral hepatitis.

2,4-Diaminoquinazolines as Dual Toll Like Receptor (TLR) 7/8 Modulators for the Treatment of Hepatitis B Virus

A novel series of 2,4-diaminoquinazolines was identified as potent dual Toll-like receptor (TLR) 7 and 8 agonists with reduced off-target activity. The stereochemistry of the amino alcohol was found to influence the TLR7/8 selectivity with the ( R) isomer resulting in selective TLR8 agonism. Lead optimization toward a dual agonist afforded ( S)-3-((2-amino-8-fluoroquinazolin-4-yl)amino)hexanol 31 as a potent analog, being structurally different from previously described dual agonists ( McGowan J. Med. Chem. 2016 , 59 , 7936 ). Pharmacokinetic and pharmacodynamic (PK/PD) studies revealed the desired high first pass profile aimed at limiting systemic cytokine activation. In vivo pharmacodynamic studies with lead compound 31 demonstrated production of cytokines consistent with TLR7/8 activation in mice and cynomolgus monkeys and ex vivo inhibition of hepatitis B virus (HBV).