نتایج جستجو برای: pyrroles
تعداد نتایج: 1881 فیلتر نتایج به سال:
Irradiation of vinylogous amide or imide 5 (R = H, alkyl, or Ac) leads to the selective formation of either crossed photoadduct 7 (R = Ac) or parallel photoadduct 8 (R = H or alkyl) as a function of the nature of the group R. The latter result leads to a novel approach to the synthesis of pyrroles, that is, 8'.
A total of 19 alkylated heterocycles (thiophenes, benzothiophenes, pyrroles, furans) were prepared (36-99% yield) from the respective pyridin-2-yl-substituted precursors employing alkylboronic acids as the C-H alkylating reagents in an oxidative (Ag2CO3 and 2,6-dimethyl-1,4-benzoquinone as oxidants) Pd-catalysed coupling reaction.
A base-catalyzed cycloisomerization of 5-cyano-pentyne bearing a terminal alkyne group has been developed under metal-free conditions. This reaction involves a tandem process providing efficient access to 3-cyano-4,5-dihydro-1H-pyrroles in good to excellent yields in an atom-economic manner with 1,3-cyano migration as the key transformation.
The reaction of zirconium(IV) porphyrinogen with water yields a dinuclear complex in which one mu-oxo ligand bridges two Zr(IV) centres, and two protons are bound to the alpha carbons of two porphyrinogen pyrroles. The reaction establishes the utility of the porphyrinogen macrocycle as a storage site for protons as well as electrons.
A new microwave-assisted rearrangement of 1,3-oxazolidines scaffolds is the basis for a new, metal-free, direct, and modular construction of tetrasubstituted pyrroles from terminal-conjugated alkynes, aldehydes, and primary amines. This new reaction manifold entails two linked domino processes in a one-pot manner with both atom- and bond-efficiency and under very simple and environment-friendly...
The first asymmetric aza-Friedel-Crafts reaction of indoles and pyrroles with isatin-derived N-Boc ketimines catalyzed by chiral phosphoric acids is reported. In general, derivatives of substituted 3-amino-2-oxindoles were obtained with excellent enantioselectivities and high yields.
A novel one-pot synthesis of N-substituted heterocycles via successive cyclization/annelation starting from primary sulfonamides is described. This process leads directly to N-sulfonyl pyrroles, indoles and carbazoles. The selection of appropriate reactant/triflic acid ratio successfully controls the formation of the desired product.
Relatively mild and highly efficient CuI-catalyzed N-arylation procedures for nitrogen-containing heterocycles (e.g., imidazoles, benzimidazoles, pyrroles, pyrazoles, indoles, triazoles, etc.) with aryl and heteroaryl halides have been developed. The protocols can be performed easily and tolerate a number of functional groups, such as ester, nitrile, nitro, ketone, free hydroxyl, and free prima...
The title compound, C(16)H(18)N(2)O(5), consists of a benzodiazepinedione system fused to a pyrrole system. The seven-membered ring adopts a boat-shaped conformation (with the methine C atom as the prow); the five-membered ring adopts an enveloped-shaped conformation (with the hydr-oxy-bearing C atom as the flap). The hydr-oxy group is hydrogen bonded to the carbonyl O atom of an adjacent mol-e...
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