نتایج جستجو برای: meso
تعداد نتایج: 7363 فیلتر نتایج به سال:
The reaction of di-(o-acetylphenyl)acetylene (1) with excess dimethyl acetylenedicarboxylate (DMAD) produced bis-DMAD adducts meso-3 and rac-3. This transformation is suggested to involve thermal rearrangement of 1 to the intermediate 3,3'-dimethyl-1,1'-biisobenzofuran (A), and subsequent Diels-Alder cycloadditions of two equivalents of DMAD to A. The isolation of trapping products meso-3 and r...
Condensation of 16-silatripyrrane with pentafluorobenzaldehyde under catalytic conditions followed by DDQ oxidation leads to 31,34-disilahexaphyrinoid--a four times reduced derivative of 31,34-disilahexaphyrin which contains two built-in silole units flanked by four tetrahedrally hybridized meso carbons. In the preferred folded macrocyclic conformation the silole rings remain perpendicular to e...
Active and highly stable oxide-supported IrNiO(x) core-shell catalysts for electrochemical water splitting are presented. IrNi(x)@IrO(x) nanoparticles supported on high-surface-area mesoporous antimony-doped tin oxide (IrNiO(x)/Meso-ATO) were synthesized from bimetallic IrNi(x) precursor alloys (PA-IrNi(x) /Meso-ATO) using electrochemical Ni leaching and concomitant Ir oxidation. Special emphas...
meso-Functionalized dipyrromethanes 6-10 were synthesized by acid-catalyzed addition of pyrrole to αposition of 2-alkenyl pyrroles. The regiochemistry of the reaction can be explained by either the formation of more stable carbocation intermediate or β-addition of α,β-unsaturated carbonyl compounds. The starting 2alkenyl pyrroles were synthesized by Aldol condensation of 2-formylpyrrole with ac...
Hexakis(pentafluorophenyl)-substituted meso-meso-linked Zn(II)-diporphyrin (9), which was prepared by the acid-catalyzed cross-condensation of 1,1,2,2-tetrapyrroethane (5) with dipyrromethane dicarbinol (6), was converted into meso-meso,β-β,β-β triply linked Zn(II)-diporphyrin 3 by oxidation with 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) and Sc(OTf)(3). Beside the red-shifted absorption spectr...
The presence of substituents at designated sites about the chlorin macrocycle can alter the spectral properties, a phenomenon that can be probed through synthesis. Prior syntheses have provided access to chlorins bearing distinct aryl substituents (individually or collectively) at the 5, 10, and 15-positions, but not the 20-position. A new Western half (5-phenyl-2,3,4,5-tetrahydro-1,3,3-trimeth...
Alumina (Al2O3) decorated anatase TiO2 nanotubes with ordered mesoporous pore walls (Al2O3/meso-TiO2 nanotubes) are successfully synthesized through vacuum pressure induction technology, and then combined with the thermal decomposition of a mesoporous TiO2 sol precursor, inside the cylindrical nanochannels of an anodic aluminium oxide (AAO) template. The decorated Al2O3 was formed by in situ de...
The persistent adrenocorticolytic DDT metabolite 3-methylsulfonyl-DDE (MeSO(2)-DDE) was originally identified in Baltic grey seals, a population suffering from adrenocortical hyperplasia. In mice, MeSO(2)-DDE induces mitochondrial degeneration and cellular necrosis in the adrenal zona fasciculata. In this study, we used precision-cut tissue slice culture to examine local CYP11B1-catalyzed irrev...
We describe the first application of our methodology for heterodimerization via diazene fragmentation towards the total synthesis of (-)-calycanthidine, meso-chimonanthine, and (+)-desmethyl-meso-chimonanthine. Our syntheses of these alkaloids feature an improved route to C3a-aminocyclotryptamines, an enhanced method for sulfamide synthesis and oxidation, in addition to a late-stage diversifica...
Reaction of meso-tetraphenylsecochlorin bisaldehyde with hydroxylamine results in the formation of the known meso-tetraphenyl-2-nitroporphyrin and the novel meso-tetraphenylimidazolophorphyrin. The products are the result of two diverging pathways of the presumed intermediate monooxime monoaldehyde that are unusual and surprising, but fully rationalized. The structures of both products were con...
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