A general one-pot synthesis of pyridines 4a-t from the reaction of dialkyl acyclic/cyclic ketones 1a-i, methyl, aryl/heteroaryl ketones 1m-r, and aldehydes bearing alpha-hydrogens 1s,t with propargylamine 2 is described. Gold and copper salts are efficient catalysts for the reaction of ketones with 2. The formation of the pyridines 4 is suggested to proceed through the sequential amination of carbonyl compounds followed by regioselective 6-endo-dig cyclization of the N-propargylenamine (N-propargyldienamine) intermediate 3(5) and aromatization reaction. Whereas the preparation of linear polycyclic pyridine 4i can be carried out by reacting cholestan-3-one 1i with 2, the angular polycyclic pyridine 4j has been obtained starting from cholest-5-en-3-one 1j. Selectivity of the reaction of polycyclic dicarbonyls 1k,l with 2 has also been investigated.
Bequeme Routine: Mehrlagige dünne Polymerfilme wurden durch Elektrophorese auf in Agarose immobilisierten Partikeln angeordnet. Anschließendes Entfernen des Kerns führte zu robusten Kapseln mit unterschiedlichen Polymerzusammensetzungen (siehe Fluoreszenzbild). Dieser Ansatz ermöglicht den vielseitigen und routinemäßigen Aufbau von nano‐ und mikroskaligen Kapseln sowie beschichteten Partikeln in sehr wenigen Prozessschritten.
Among biofuels, the bio-oil produced
by hydrothermal liquefaction
of waste biomass can be considered an alternative to fossil fuels
in industry as well as transport and heating compartments. The bio-oil
complex composition is directly dependent upon the specific biomass
used as feedstock and the process used for the chemical conversion.
The coexistence of proteins and lipids can explain, in principle,
the high percentage of fatty acid amides found in the produced bio-oil.
In the present study, the amides in a sample of bio-oil have been
separated by gas chromatography and identified at first on the basis
of their electron impact (EI) mass spectra. To distinguish between N-alkyl isomers, standard amides have been synthesized and
analyzed. Because the most reasonable origin of fatty acid amides
in hydrothermal bio-oils is the condensation reaction between fatty
acids and the decarboxylation products of amino acids, a series of
model experiments have been carried out by reacting hexadecanoic acid,
at high temperature and pressure, with each of the 20 amino acids
constitutive of proteins, looking for the formation of fatty acid
amides. Remarkably, by such experiments, all of the amides present
in the bio-oil have been recognized as hydrothermal coupling compounds
of the decomposition products of amino acids with fatty acids, thus
allowing for their structural elucidation and, also important, confirming
their (bio)chemical origin.
[reaction: see text] The gold-catalyzed reaction of 2-alkynyl-phenylamines with alpha,beta-enones represents a new general one-pot entry into C-3-alkyl-indoles by sequential reactions. Gold-catalyzed sequential cyclization/alkylation, N-alkylation/cyclization, or N-alkylation/cyclization/alkylation reactions leading to different indoles can be directed by changing the 2-alkynyl-phenylamine 1/alpha,beta-enone 3 ratio and the reaction temperature. Unusual gold-catalyzed rearrangement reaction of indoles are observed at 140 degrees C. New gold-catalyzed formation of propargyl-alkyl ether under mild conditions and the hydration reaction of N-acetyl-2-ethynyl-phenylamine are reported.
3-Unsubstituted indoles undergo regioselective alkylation at the 3-position of the indole nucleus through gold-catalyzed conjugated addition type reaction with α,β-enones. 3-Substituted indoles undergo C-2 alkylation. Sequential C-3/C-2 gold catalyzed alkylation of the indole with dibenzylidene acetone gives a polycyclic indole b-annulated with a seven-membered cycle
Abstract:The gold-catalysed direct couplings of indoles 1 and pyrroles 5 with 1,3-dicarbonyls 2 is described. This new method for C À C bond formation allows high functional group tolerance, regioselectivity, and scope under relatively mild conditions. Moreover, the 3-alkenylindoles 3 can be readily available through gold-catalysed sequential cyclization/alkenylation reaction of 2-alkynylanilines derivatives 4 with 1,3-dicarbonyls 2.
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