نتایج جستجو برای: substituted pyrrole

تعداد نتایج: 42480  

2015
R. Raja M. Suresh R. Raghunathan A. SubbiahPandi

In the title compounds, C23H27NO2S, (I), and C21H23NO2S, (II), the pyrrole rings have envelope conformations with the C atom substituted by the benzene ring as the flap. In the third title compound, C20H21NO3S, (III), the isoxazole ring has a twisted conformation on the C-C bond substituted by the benzene ring and the carboxyl-ate group. In all three compounds, the thio-pyran ring has a half-ch...

Journal: :The Journal of organic chemistry 2001
Y Chen C J Medforth K M Smith J Alderfer T J Dougherty R K Pandey

To investigate the effects of electron-donating and electron-withdrawing substituents upon the reaction of porphyrins with osmium tetraoxide, and the pinacol-pinacolone rearrangement of the resulting diols, a series of meso-substituted porphyrins were prepared by total synthesis. Porphyrins with electron-donating substitutents at the meso-positions gave vic-dihydroxychlorins in which the adjace...

ژورنال: :international journal of new chemistry 0

abstract: electrical sensitivity of a boron nitride nanotube (bnnt) was examined toward pyrrole (c5h6n) molecule by using density functional theory (dft) calculations at the b3lyp/6-31g (d) level, and it was found that the adsorption energy (ead) of pyrrole on the pristine nanotubes is a bout -16.37kcal/mol. but when nanotube have been doped with si and al atomes, the adsorption energy of pyrro...

2008
E. Milanesio S. M. Chiacchiera J. J. Silber E. N. Durantini

A convenient procedure for the synthesis of 5-(4-acetamidophenyl)-10,15,20tris(4-substituted phenyl) porphyrins from dipyrrolomethane is reported. meso-(4Substituted phenyl) dipyrrolomethanes were obtained in yields of 72-84%. The amide porphyrins were isolated with appreciable yields of 15-17%. Introduction The design of new material systems involves the synthesis of asymmetric porphyrins. Thu...

Journal: :Physical chemistry chemical physics : PCCP 2007
Pablo Campomanes María Isabel Menéndez Gloria Inés Cárdenas-Jirón Tomás Luis Sordo

B3LYP/6-31G(d) optimization of porphyrin, tetraphenylporphyrin and their 21,23-diheteroatom substituted derivatives with O, S, and Se heteroatoms was performed. A planar macrocycle was found in all cases except 21,23-dioxatetraphenylporphyrin which presents only slight deviations from planarity. A Bader analysis uncovers the presence of S-S and Se-Se interactions in the four corresponding heter...

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