نتایج جستجو برای: pyrrole
تعداد نتایج: 3583 فیلتر نتایج به سال:
Synthesis of directly linked diazine isosteres of pyrrole-polyamide that photochemically cleave DNA.
A distamycin model containing an isosteric diazine linked pyrrole has been designed and synthesized. The key steps of the synthesis involved the successful diazotization of the 4-amino-pyrrole derivatives to give the diazomium salts, which undergo coupling reactions with N-methylpyrrole to yield the directly linked diazine compounds. The amide isosteric-diazine pyrrole I demonstrated photo-indu...
The title compound, C(13)H(14)N(2)O(2), is a natural product isolated from Cicer arietinum L. (chickpea). The benzene ring and pyrrole rings display planar conformations and the piperidine ring has a half-chair conformation. Inter-molecular C-H⋯π inter-actions between a methyl H atom and the pyrrole ring of an adjacent mol-ecule are present in the crystal structure.
We study the relaxation dynamics of pyrrole after excitation with an 8 eV pump pulse to a state just 0.2 eV below the ionization potential using vacuum ultraviolet/ultraviolet pump probe spectroscopy. Our measurements in conjunction with electronic structure calculations indicate that pyrrole undergoes rapid internal conversion to the ground state in less than 300 fs. We find that internal conv...
Intramolecular N-arylation of pyrrole and indole carboxamides and carboxylates linked with a pendant haloarene by Cu-catalyzed reactions to synthesize pyrrole and indole quinoxalinone and oxazinone derivatives is reported. The ring closure reactions were carried out by conventional heating and MW irradiation. The use of conventional heating affords moderate to good yields of the quinoxalinone a...
In the title compound, C26H23NO2, the dihedral angles between the pyrrole ring and the two phenyl rings are 58.1 (6) and 71.5 (5)°. The mean planes of the 5-methyl-benzene ring and the carboxyl group are twisted by 89.5 (3) and 22.1 (9)°, respectively, from the pyrrole ring. In the crystal, weak C-H⋯O inter-actions lead to supra-molecular layers in the ab plane.
The mol-ecule of the title compound, C(18)H(28)N(2), composed of two 2,5-dimethyl-pyrrole groups linked by a hexane chain, lies across a crystallographic inversion centre. The mean plane of the pyrrole ring is almost perpendicular to the mean plane of the central chain, making a dihedral angle of 89.09 (8)°. The crystal structure is stabilized by inter-molecular C-H⋯π inter-actions.
A new and easy method for synthesis of symmetric pyrrole-2,5-dicarboxylate derivatives via a simple titanium(IV)-mediated oxidative dimerization of 2-azidocarboxylic esters is described. The process involves a transformation of titanium(IV) enolates into nonisolated 2-iminoesters, which undergo an oxidative coupling and ring closure to give the aromatic pyrrole system. A mechanism, scope and li...
Multireference configuration interaction (MRCI) calculations have been performed for pyrrole with the aim of providing an explanation for the experimentally observed photochemical deactivation processes. Potential energy curves and minima on the crossing seam were determined using the analytic MRCI gradient and nonadiabatic coupling features of the COLUMBUS program system. A new deactivation me...
N-arylpyrrole-based dyes possessing excellent opto-electronic properties are promising candidates for two-photon fluorescence labeling materials. The systematic investigation of novel N-arylpyrrole derivatives is of great importance for both fine-tuning electronic spectra and designing two-photon absorption (2PA) materials. We thoroughly studied influences of the π-conjugated center and N-subst...
The vibrations of pyrrole, N-deuteropyrrole, N-fluoropyrrole, N-aminopyrrole and N-methylpyrrole are studied. evolution the vibrational wavenumbers pyrrole is examined, as mass nitrogen-bonded hydrogen atom artificially increased. It found that some very sensitive to substituent bonded nitrogen, this can be viewed mixing increases; however, these mixings stablilize by time a 14 mu reached. A co...
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