RESUMO
Herein, we describe an efficient transition-metal-free regioselective C3alkylation of indoles for the synthesis of bis(indolyl)methanes and 3-styryl indoles. Nitrobenzene is employed as the oxidant to oxidize the alcohols in the presence of a strong base and the reaction avoids the use of transition metals such as Ru and Mn. The protocol provides a favorable route to access biologically active compounds such as arundine, vibrindole A, and turbomycin B.
RESUMO
A convenient one-pot, three-component reaction has been developed for the synthesis of 3-aroylimidazo[1,2-a]-N-heterocycles from aryl ketones and 2-amino-N-heterocycles using dimethyl sulfoxide as a methylene donor. The reaction proceeds smoothly catalyzed by I2 in the presence of K2S2O8 and affords the desired products in moderate to good yields. This protocol offers significant superiority in accessing biologically active 3-aroylimidazo[1,2-a]-N-heterocycles with various substitution patterns.
Assuntos
Dimetil Sulfóxido , Cetonas , CatáliseRESUMO
A simple and practical domino protocol for the selective synthesis of 2-aroylbenzothiazoles and 2-aryl benzothiazoles catalyzed by I2 is developed under metal-free conditions. The reaction outcomes are exclusively controlled by the reaction oxidant/medium. With DMSO employed as both the solvent and the oxidant, an oxidation of aromatic methyl ketones takes precedence over the condensation with 2-aminobenzenethiols. On the other hand, when the reaction was carried out in PhNO2 or in 1,4-dioxane containing PhNO2, the condensation of aromatic methyl ketones with 2-aminobenzenethiols has priority to form imines which is followed by an oxidation of the methyl group from ketones to afford 2-arylbenzothiazoles as a sole product. The PhNO2/I2 co-catalytic system is proposed first time.
RESUMO
A novel procedure for a one-pot cascade reaction of o-aminoacetophenones and aryl/aliphatic isocyanates catalyzed/oxidized by the [Pd]/[Ag] system was developed. The reaction involves two C-N bond and one C-C bond formations during the double annulation process and the desired indoloquinazolinones and derivatives were afforded up to 81% yields from readily available substrates with a tolerance of a broad variety.
RESUMO
An unprecedented eco-friendly multi-component domino reaction for the synthesis of novel N,O-acetals is reported. The protocol involves sequential coupling, [1,5]-hydride transfer and hetero-Diels-Alder cyclization. This new strategy enables direct α,ß-difunctionalization of cyclic amines utilizing enamines generated in situ. The methodology features high atom and step economy, excellent regioselectivity, a simple work-up procedure and molecular diversity.
RESUMO
The title compound, C(26)H(18)Cl(2)O, is a heterocyclic structure consisting of a benzo[f]chromene ring and two aromatic rings. The non-H atoms of the benzo[f]chromene ring are almost coplanar (rms deviation = 0.107â Å), and the methyl C atom lies 1.340â (4)â Å from the mean plane of the benzo[f]chromene ring. The chromene ring forms dihedral angles of 88.45â (2)° with the benzene ring linked to the quaternary C atom and 50.74â (3)° with the benzene ring linked to the 3-position, while the dihedral angle between the two benzene rings is 67.58â (3)°.
RESUMO
1,2-Dihydro-1,3,5-triazines and symmetrical 1,3,5-triazines were obtained in up to 81% yields from amidines and N,N-dimethylethanolamine catalyzed by CuCl2. The reaction involves three C-N bond formations during the oxidative annulation process and the mechanism was proposed. This efficient synthesis of 1,2-dihydro-1,3,5-triazines was developed for the first time.
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Organic solvent soluble gold nanoparticles based on pillar[5]arenes were prepared for the first time. They can reversibly aggregate and disassemble based on photo[4+4] cycloaddition of anthracene and can be used as recyclable catalysts.
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The formation of a pH-responsive fluorescent [5]pseudorotaxane by self-assembly of cationic water-soluble pillar[5]arenes and a tetraphenylethene derivative was reported.
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Various nanomorphologies were obtained by simply changing the fabrication conditions, such as the pH of the system, different solvent, or different concentration, of bola-amphiphilic pillar[5]arene Bola-AP5. Importantly, hybrid microtubules as a microreactor were successfully prepared by directly reducing AuCl4(-) on the surface of Bola-AP5-based tubular structures in water.
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A pillar[6]arene-based supramolecular amphiphile has been constructed in water. The supramolecular amphiphile formed vesicles, which could be regulated by pH, light and enzymes, and thus the loaded dye in the vesicles could be released in a controlled manner.