3 research outputs found
Probing the Characteristics of Mono- or Bimetallic (Iron or Cobalt) Complexes Bearing 2,4-Bis(6-iminopyridin-2-yl)‑3<i>H</i>‑benzazepines: Synthesis, Characterization, and Ethylene Reactivity
A series
of 2,4-bisÂ(6-iminopyridin-2-yl)-3<i>H</i>-benzazepines and
the mono- or bimetallic (Fe<sup>2+</sup> or Co<sup>2+</sup>) complexes
thereof were synthesized and characterized. All title complexes, when
activated by MAO or MMAO, exhibited high activities of up to 4.0 ×
10<sup>7</sup> g (mol of Fe)<sup>−1</sup> h<sup>–1</sup> for ethylene oligomerization and polymerization. The ironÂ(II) precatalysts
generally showed higher activities and produced a wider distribution
of products (including oligomers and polyethylene) than did their
corresponding cobaltÂ(II) analogues. The bimetallic precatalysts exhibited
higher (almost twice) activities in comparison to their monometallic
analogues. The distribution of the resulting oligomers closely resembled
the Schultz–Flory rule
Probing the Characteristics of Mono- or Bimetallic (Iron or Cobalt) Complexes Bearing 2,4-Bis(6-iminopyridin-2-yl)‑3<i>H</i>‑benzazepines: Synthesis, Characterization, and Ethylene Reactivity
A series
of 2,4-bisÂ(6-iminopyridin-2-yl)-3<i>H</i>-benzazepines and
the mono- or bimetallic (Fe<sup>2+</sup> or Co<sup>2+</sup>) complexes
thereof were synthesized and characterized. All title complexes, when
activated by MAO or MMAO, exhibited high activities of up to 4.0 ×
10<sup>7</sup> g (mol of Fe)<sup>−1</sup> h<sup>–1</sup> for ethylene oligomerization and polymerization. The ironÂ(II) precatalysts
generally showed higher activities and produced a wider distribution
of products (including oligomers and polyethylene) than did their
corresponding cobaltÂ(II) analogues. The bimetallic precatalysts exhibited
higher (almost twice) activities in comparison to their monometallic
analogues. The distribution of the resulting oligomers closely resembled
the Schultz–Flory rule
Discovery of A‑971432, An Orally Bioavailable Selective Sphingosine-1-Phosphate Receptor 5 (S1P<sub>5</sub>) Agonist for the Potential Treatment of Neurodegenerative Disorders
S1P<sub>5</sub> is one of 5 receptors for sphingosine-1-phosphate and is
highly expressed on endothelial cells within the blood–brain
barrier, where it maintains barrier integrity in in vitro models (J. Neuroinflamm. 2012, 9, 133). Little more
is known about the effects of S1P<sub>5</sub> modulation due to the
absence of tool molecules with suitable selectivity and drug-like
properties. We recently reported that molecule A-971432 (Harris , 2010) (<b>29</b> in this paper) is
highly efficacious in reversing lipid accumulation and age-related
cognitive decline in rats (Van der Kam, , AAIC 2014). Herein we describe the development of a series of selective S1P<sub>5</sub> agonists that led to the identification of compound <b>29</b>, which is highly selective for S1P<sub>5</sub> and has
excellent plasma and CNS exposure after oral dosing in preclinical
species. To further support its suitability for in vivo studies of
S1P<sub>5</sub> biology, we extensively characterized <b>29</b>, including confirmation of its selectivity in pharmacodynamic assays
of S1P<sub>1</sub> and S1P<sub>3</sub> function in rats. In addition,
we found that <b>29</b> improves blood–brain barrier
integrity in an in vitro model and reverses age-related cognitive
decline in mice. These results suggest that S1P<sub>5</sub> agonism
is an innovative approach with potential benefit in neurodegenerative
disorders involving lipid imbalance and/or compromised blood–brain
barrier such as Alzheimer’s disease or multiple sclerosis