نتایج جستجو برای: dimethoxy porphyrins
تعداد نتایج: 6278 فیلتر نتایج به سال:
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...
Porphyrins in calcareous structures with special reference to bones from porphyric cattle and swine.
Bones from porphyric animals are treated first with 40% sodium hydroxide and subsequently with concentrated hydrochloric acid which dissolves the chalky residue from the alkaline digestion under violent foaming. The porphyrins are precipitated from the acid solution at pH ca. 3 together with calcium salts and subsequently washed and dissolved in about 50% acetic acid. The solution is then dilut...
The synthesis of a pair of electron-deficient porphyrin building blocks and their resulting coordinatively linked supramolecular assemblies are described. The perfluorophenyl substituted porphyrins feature pendant pyridines which, upon reaction with Re(CO)5Cl assemble into discrete dimers and tetramers, as dictated by the geometry of the porphyrin monomer. The resulting supramolecular complexes...
We describe a new, specific, quantitative method for fecal blood, based on conversion of nonfluorescing heme to fluorescing porphyrins, that obviates serious deficiencies inherent in currently used tests. A two-reagent system is used to determine the two hemoglobin-related fractions that are found in feces. The hot citric acid extract includes only the variable fraction of porphyrins that have ...
Porphyria cutanea tarda is thought to result from an inherited deficiency of uroporphyrinogen decarboxylase (EC 4.1.1.37) in some patients. Present methods for determining uroporphyrinogen decarboxylase activity are time consuming, so we examined the pattern of porphyrins formed from porphobilinogen by hemolysates as a possible marker for hereditary porphyria cutanea tarda. After the hemolysate...
straightforward conversion of (+)-6,8-dimethoxy-3,4-dihydro-3- undecylisocoumarin (3) to the title isocoumarin was carried out. hydrolytic ring opening of (3) afforded the hydroxy acid (4) which was immediately oxidized to keto acid (5) using chromic acid, cyclodehydration of (5) afforded the 6,8- dimethoxy-3-undecylisocoumarin (6) which on selective demethylation of 8- methoxy group furnished ...
BACKGROUND/AIMS 3,4-Dimethoxy-2-phenylethylamine is catalyzed to its aldehyde derivative by monoamine oxidase B, but the subsequent oxidation into the corresponding acid has not yet been studied. Oxidation of aromatic aldehydes is catalyzed mainly by aldehyde dehydrogenase and aldehyde oxidase. METHODS The present study examines the metabolism of 3,4-dimethoxy-2-phenylethylamine in vitro and ...
Recent investigations concerning the significance of porphyrins in erythrocytes indicate a need for a rapid quantitative assay, easily adaptable to routine clinical use. To till this need, we have developed a simplified procedure for the measurement of porphyrins (essentially protoporphyrin) in whole blood. Blood is stirred with acetone-ethyl acetate and the porphyrins are extracted with formic...
Solar fuel generation requires the efficient capture and conversion of visible light. In both natural and artificial systems, molecular sensitizers can be tuned to capture, convert, and transfer visible light energy. We demonstrate that a series of metal-free porphyrins can drive photoelectrochemical water splitting under broadband and red light (λ > 590 nm) illumination in a dye-sensitized TiO...
The aromatic character of porphyrins can also be seen by NMR spectroscopy. Studies performed in the last decades demonstrated that 1H NMR spectra are very informative and adequately reflect the structural features of porphyrins.[1] The presence of the extended delocalized -electron system of the porphyrin macrocycle gives rise to a strong ring current in the molecules placed in the magnetic fi...
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