نتایج جستجو برای: pyrroles
تعداد نتایج: 1881 فیلتر نتایج به سال:
In this paper, a simple and highly efficient ruthenium-catalyzed direct C3 alkylation of indoles with various α,β-unsaturated ketones without chelation assistance has been developed. This novel C-H activation methodology exhibits a broad substrate scope such as different substituted indoles, pyrroles, and other azoles. Further synthetic applications of the alkylation products can lead to more a...
Various tetrasubstituted pyrroles/pyrazoles have been prepared from nitro-substituted 1,3-enynes with aromatic amines/hydrazines via a copper-catalyzed cascade aza-Michael addition, cyclization and aromatization at room temperature. This protocol is also effective for the synthesis of tetrasubstituted pyrazoles in high yields.
This review summarizes strategies by which chiral pyrroles, both simple and complex, have been prepared: strategies include formation of the pyrrolic ring using starting materials appended with chirality, as well as the attachment of chirality to a pre-formed pyrrolic ring.
Gold-catalysed, divergent synthesis of 2-sulfonylmethyl pyrroles and dihydropyridines from N-propargyl-N-vinyl sulfonamides has been achieved. Echavarren's gold(I) catalyst promoted the formation of pyrrole derivatives whereas the combination of PPh3AuCl and AgSbF6 afforded dihydropyridines. The aza-enyne precursors for the cycloisomerisation reaction were prepared by a base-mediated formal vin...
The reaction of Meldrum's acid, pyrrolide, and allyl carbonates allows a multicomponent decarboxylative coupling to form allylated acyl pyrroles. This strategy is made possible by the in situ formation of β-oxo carboxylates from Meldrum's acid. Subsequent decarboxylative enolate formation and electrophilic allylation complete the reaction. Addition of benzylidene malononitriles as good Michael ...
Nano-copper(0) stabilized on alumina prepared from Cu-Al hydrotalcite has been reported for completely regioselective synthesis of 2,4-disubstituted pyrroles from unactivated terminal aromatic/aliphatic alkynes and isocyanides. The reaction is operationally simple, involves ligand-free inexpensive nano-copper, and affords products in high yields.
We have succeeded in the visible light-mediated synthetic use of α-aminoalkyl radicals derived from α-silyl secondary amines toward addition to α,β-unsaturated carbonyl compounds. The resulting γ-aminocarbonyl compounds are converted into γ-lactams and pyrroles in a one-pot process.
Using a simple and accessible Teflon AF-2400 based tube-in-tube reactor, a series of pyrroles were synthesised in flow using the Paal-Knorr reaction of 1,4-diketones with gaseous ammonia. An inline flow titration technique allowed measurement of the ammonia concentration and its relationship to residence time and temperature.
Oxalyl-tethered pyrroles can be doubly bridged with two difluoroboron chelating units to yield bright orange dyes. Interestingly, in polar organic solvents, the addition of fluoride and cyanide result in reversible detachment of the otherwise stable difluoroboron bridges, resulting in sharp changes in color. Thus, this novel compound behaves as a highly selective chromogenic sensor for fluoride...
A highly efficient and selective Ru-catalyzed direct C2-olefination of indoles, pyrroles, and carbazoles assisted by a removable N-dimethylcarbamoyl group has been developed by using O2 as the terminal oxidant. Both electron-deficient and unactivated alkenes are applicable to the protocol.
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