نتایج جستجو برای: dehydro aromatization
تعداد نتایج: 1931 فیلتر نتایج به سال:
A regioselective synthesis of substituted pyrroloquinolinones via a ruthenium-catalyzed oxidative cyclization of substituted N-carbamoyl indolines with alkynes is described. The cyclization reaction was compatible with various symmetrical and unsymmetrical alkynes including substituted propiolates. Later, we performed the aromatization of pyrroloquinolinones into indole derivatives in the prese...
An efficient amine-/ruthenium-catalyzed three-step process for the synthesis of Nefopam analogues was achieved through combinations of cascade enamine amination/iso-aromatization/allylation and diene or enyne metathesis as key steps starting from functionalized Hagemann's esters. In this communication, we discovered the application of ruthenium-catalysis on olefins containing free amines withou...
DANNENBERG and HEBENBROCK obtained a fluorescent hydrocarbon, C27H34, by refluxing vitamin D3 with chloranil in anisole (bp 155.5•Ž) for 1 hr (35% yield), to which a structure possessing the styryl indene chromophore was assigned (1). During the course of our study on a fl uorometric determination of vitamin D, we found this reaction to be unsuited for analytical purposes mainly because of its ...
BACKGROUND Repeated electroacupuncture (EA) stimulation is known to stimulate the activity of the hypothalamus-pituitary-adrenal axis, and to enhance the circulation level of estrogen in the ovariectomized rats. To explore the source of the increased circulation estrogen, the extragonadal aromatization was detected. METHODS Female rats were divided into five groups: 1) intact (INT), 2) intact...
The first synthesis and characterization of [9]-, [12]-, and [18]cycloparaphenylene was demonstrated utilizing a novel aromatization reaction. We refer to these fascinating structures as "carbon nanohoops" due to their structural similarity to carbon nanotubes. Additionally, we have utilized computational methods to understand the unique properties of these fully conjugated macrocycles.
Miltiradiene (1) is the precursor of phenolic diterpenoids such as ferruginol (2), requiring aromatization and hydroxylation. While this has been attributed to a single cytochrome P450 (CYP76AH1), characterization of the rosemary ortholog CYP76AH4 led to the discovery that these CYPs simply hydroxylate the facilely oxidized aromatic intermediate abietatriene (3).
Novel syntheses and properties of meso-tetraaryl-octabromo-tetranaphtho[2,3]porphyrins (Ar4Br8TNPs).
o-Quinodimethane (o-QDM) generated from benzosultine was used to extend the pyrrole system for the preparation of octabromo-tetranaphtho[2,3]porphyrins via oxidative aromatization. The properties of these bromoporphyrins were presented and chemical transformation via Pd-catalyzed Suzuki reaction was also effectively achieved.
Polysubstituted phenols are efficiently assembled from one aldehyde and two different methyl ketones in a one-pot operation via a newly base-induced regiospecific [4 + 1 + 1] annulation and sequential metal-free oxidative aromatization using molecular oxygen (from air) as the sole oxidant at room temperature.
A new chiral salen ligand based on two ferrocenyl groups is designed. Unlike known salen ligands, of which chirality originates from central and axial chiral centers, the chirality of this ligand comes from the planar chiral ferrocenyl groups. The ligand is synthesized stereoselectively using a novel aromatization strategy starting from a ferrocene derivative, which was readily prepared using a...
A Pd-catalyzed addition of boronic acids to ynol ethers has been realized, delivering trisubstituted vinyl ethers in good yields with perfect control of the regio- and stereoselectivity. The reaction proceeds under mild conditions and exhibits excellent functional group compatibility. Moreover, the resultant products can be converted into pentasubstituted benzenes via the tandem Diels-Alder/aro...
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