A series of hydroxyacetophenones was prepared for evaluation as leukotriene B4 (LTB4) receptor antagonists, culminating in 1-5-ethyl-2-hydroxy-4-6-methyl-6-(1H-tetrazol-5- yl)heptyloxyphenylethanone ...(compound 35, LY255283). Using an assay for inhibition of specific 3HLTB4 binding to human PMN, we found that substitution of a nonpolar substituent in the 5-position was required for activity. Best activity was realized with hydrogen in the 3-position, hydroxyl in the 2-position, short chain alkyl ketone in the 1-position, and a six- or eight-carbon chain linking the oxygen in the 4-position with an unsaturated terminal function. Compound 35, having an IC50 of 87 nM in the binding assay, was chosen for further preclinical evaluation.
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•Synthesis of isolated Zn(II) alkyl sites on SiO2 via atomic layer deposition.•Single-site nature of Zn(II) alkyl sites was confirmed by spectroscopic measurements (e.g., ...XAS).•Open-shell, tricoordinate ethyl-Zn(II) sites exhibit higher activity.•High Zn(II) dispersion produces Zn/SiO2 catalysts with improved activity and stability.
Alkyl-zinc and zinc oxide-type sites were synthesized via atomic layer deposition on high-surface-area silica using an integrated atomic layer deposition-catalysis instrument (I-ALD-CAT). One-cycle ALD experiments using diethylzinc (DEZ) afforded Zn/SiO2 systems that provided key insights into the reactivity and stability of Zn sites as a function of dispersion at the submonolayer level. The I-ALD-CAT tool design allowed for systematic comparison of the reactivity of different grafted zinc sites. Open-shell 16-electron, tricoordinate ethyl zinc-silica sites exhibit higher activity in propane hydrogenation-dehydrogenation compared to 18-electron, tetracoordinate zinc oxide-type centers. Silica surface saturation with Zn(II) sites (∼75% of a monolayer) results in facile zinc agglomeration and catalyst deactivation under reaction conditions. Reduced DEZ dosing coupled with thermal substrate pretreatment techniques (e.g., dehydration under vacuum) resulted in increased Zn dispersion and produced Zn/SiO2 catalysts with improved activity and stability under propylene hydrogenation (200°C) and propane dehydrogenation (550°C) conditions.
Cryptic diversity and symbiont interactions in rock-posy lichens Leavitt, Steven D; Ekaphan KraichakauthorDepartment of Botany, Kasetsart University, Bangkok 10900, Thailand; Jan VondrakauthorFaculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 1176, Praha 6, Suchdol, Czech Republic ...
2015
Journal Article
Hispanics in America in 2000 Durand, Jorge; Massey, Douglas S; Charvet, Fernando ...
Social science quarterly,
03/2000, Letnik:
81, Številka:
1
Journal Article
Section 269 and Postacquisition Losses Bixler, John M.; Simmons, Sherwin P.; Bean, Larry L.
American Bar Association journal,
09/1963, Letnik:
49, Številka:
9
Journal Article
African-Americans have been under-represented in genetic studies of rheumatoid arthritis (RA) susceptibility and severity. Genetic and non-genetic factors influencing the radiographic severity of RA ...and its response to treatment are poorly understood, particularly in African-Americans. The Consortium for the Longitudinal Evaluation of African-Americans with early RA (CLEAR) Registry, a collaborative effort among four institutions in the southeast USA, will hopefully provide a useful resource to study these issues.
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