نتایج جستجو برای: bromination
تعداد نتایج: 805 فیلتر نتایج به سال:
Through a novel sequence of aminodiene Diels-Alder reactions, amidofurans 18a-c were converted to tricyclic ketones 21a-c in moderate to good yields. Ketone 21a could be converted to Uhlé's ketone (6) by cleaving the tert-butyl carbamate and oxidatively removing the methyl ester. Tricycle 21a readily underwent bromination to give 22. Formation of the corresponding enol triflate 25 followed by c...
A number of 4-aryl- and 4-alkynyl-substituted 6H-1,2-oxazines 8 and 9 have been prepared in good yields via cross coupling reactions of halogenated precursors 2, which in turn are easily accessible by bromination of 6H-1,2-oxazines 1. Lewis-acid promoted reaction of 1,2-oxazine 9c with 1-hexyne provided alkynyl-substituted pyridine derivative 12 thus demonstrating the potential of this approach...
A convenient synthesis of six phenolic diarylpropanes has been formulated. A CuBr2-catalyzed regioselective reaction was the key step for bromination of the arylpropanes. All the compounds showed good cytotoxicity to the human lung cancer A549 cell line. However, only one of these compounds induced apoptosis and a G1 cell cycle arrest by augmenting cellular ROS status. Introduction of bromo-sub...
We report a novel organocatalytic one-pot cascade bromination-Michael-type Friedel-Crafts alkylation dearomatization-nucleophilic rearrangement aromatization cascade process for the direct α-indolylation of unfunctionalized enals from readily available indoles with good yields and high E selectivity. The simplicity and practicality of its high efficiency for formation of a new C(sp(2))-C(sp(2))...
The heterocyclic ring of the title compound, C9H7BrO2, obtained by bromination of 4-chromanone with copper bromide, adopts a half-chair conformation. The supramol-ecular structure is governed by a weak C-H⋯O hydrogen bond. There is also π-π stacking between symmetry-related benzene rings; the centroid-centroid distance is 3.9464 (18), the perpendicular distance between the rings is 3.4703 (11) ...
A one-pot protocol, effecting 14-fold bromination with elemental bromine, has afforded copper β-octabromo-meso-tris(2,6-dibromo-3,5-dimethoxyphenyl)corrole, a new bis-pocket metallocorrole. The Cu complex underwent smooth demetalation under reductive conditions, affording the free corrole ligand, which in turn could be readily complexed to MnIII and AuIII. A single-crystal X-ray structure was o...
Cyanogen halides are known substances for the cyanating reaction. There are a few evidences for bromination reaction too. On the other hand carbenes are known as very important substances due to their remarkable reactions. Unfortunately carbenes at room temperature are very unstable and there is not a simple method for preparation of them. In most cases the isolation is not possible. We have re...
The first total syntheses of schilancidilactones A and B, schilancitrilactone A, and 20-epi-schilancitrilactone A have been accomplished using a nickel-catalyzed cross coupling of alkyl bromide with vinyl stannane as the final step. The other key steps include late-stage C(sp)–H bromination, the oxidative cleavage of a diol to provide the requisite ketone and ester for schilancidilactones A and...
A new, simplified method for the synthesis of dimethyl aryl acylsulfonium salts has been developed. A series of dimethyl aryl acylsulfonium bromides were prepared by the reaction of aryl methyl ketones with hydrobromic acid and dimethylsulfoxide (DMSO). This sulfonium salt confirms that bromine production and the bromination reaction take place in the DMSO-HBr oxidation system. What's more, it ...
An "inorganic micelle" structure that has a hydrophilic cavity and hydrophobic surface has been synthesized. The inorganic micelles possess large surface area and controllable hydrophobic/hydrophilic interface. It shows high catalytic efficiency and great recyclability in the bromination of alcohols. This work suggests that inorganic micelles may be suitable for selective organic syntheses as w...
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