4 research outputs found
Diastereoselective Synthesis of 2‑Phenyl-3-(trifluoromethyl)piperazines as Building Blocks for Drug Discovery
The synthesis of enantiomerically
pure <i>cis</i>- and <i>trans</i>-2-phenyl-3-(trifluoromethyl)piperazines
is described.
It involved, as the key step, a diastereoselective nucleophilic addition
of the Ruppert–Prakash reagent (TMSCF<sub>3</sub>) to α-amino
sulfinylimines bearing Ellman’s auxiliary. This methodology
allows an entry into hitherto unknown trifluoromethylated and stereochemically
defined piperazines, key scaffold components in medicinal chemistry
Optimization of 1,4-Oxazine β‑Secretase 1 (BACE1) Inhibitors Toward a Clinical Candidate
In previous studies,
the introduction of electron withdrawing groups
to 1,4-oxazine BACE1 inhibitors reduced the p<i>K</i><sub>a</sub> of the amidine group, resulting in compound <b>2</b> that showed excellent in vivo efficacy, lowering Aβ levels
in brain and CSF. However, a suboptimal cardiovascular safety margin,
based on QTc prolongation, prevented further progression. Further
optimization resulted in the replacement of the 2-fluoro substituent
by a CF<sub>3</sub>-group, which reduced hERG inhibition. This has
led to compound <b>3</b>, with an improved cardiovascular safety
margin and sufficiently safe in GLP toxicity studies to progress into
clinical trials
1,4-Oxazine β‑Secretase 1 (BACE1) Inhibitors: From Hit Generation to Orally Bioavailable Brain Penetrant Leads
1,4-Oxazines
are presented, which show good in vitro inhibition
in enzymatic and cellular BACE1 assays. We describe lead optimization
focused on reducing the amidine p<i>K</i><sub>a</sub> while
optimizing interactions in the BACE1 active site. Our strategy permitted
modulation of properties such as permeation and especially P-glycoprotein
efflux. This led to compounds which were orally bioavailable, centrally
active, and which demonstrated robust lowering of brain and CSF Aβ
levels, respectively, in mouse and dog models. The amyloid lowering
potential of these molecules makes them valuable leads in the search
for new BACE1 inhibitors for the treatment of Alzheimer’s disease
Identification of a Novel Orally Bioavailable Phosphodiesterase 10A (PDE10A) Inhibitor with Efficacy in Animal Models of Schizophrenia.
We
report the continuation of a focused medicinal chemistry program aimed
to further optimize a series of imidazo[1,2-<i>a</i>]pyrazines
as a novel class of potent and selective phosphodiesterase 10A (PDE10A)
inhibitors. In vitro and in vivo pharmacokinetic and pharmacodynamic
evaluation allowed the selection of compound <b>25a</b> for
its assessment in preclinical models of psychosis. The evolution of
our medicinal chemistry program, structure–activity relationship
(SAR) analysis, as well as a detailed pharmacological profile for
optimized lead <b>25a</b> are described