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...

Porphyrinogens were determined in very fresh, diluted morning urine in two types of hepatic porphyria, using a simple and very quick spectrophotometric method. It was shown that acidification by itself is insufficient for the complete conversion of colourless porphyrinogens into porphyrins in photometric determination of porphyrins in diluted urine. A correlation was shown between percentual co...

The ability of erythrocytes to synthesize porphyrins from delta-aminolaevulic acid was compared in healthy people, patients with true iron-deficiency anaemia, and anaemic patients with rheumatoid arthritis. Porphyrin synthesis was found to be impaired in true iron deficiency but not in rheumatoid arthritis cases showing a similar degree of anaemia. The delta-aminolaevulic acid dehydratase activ...

A micromethod for detecting and determining various porphyrins extracted from biological materials, especially nervous tissues (I), is needed. The technique of filter paper chromatography by Consden, Gordon, and Martin (a), with modification by Williams and Kirby’s capillary ascent (3), has been applied to the problem in this study. The recent paper by Nicholas and Rimington (4) on partition ch...

The epoxidation of olefins with tetra n-butylammonium periodate, n-Bu4/NIO4, is catalyzed by six different tetrakis (4-substituted phenyl) porphyrinatomanganese(III) acetate, Mn(T4-XPP)OAc, Complexes in the presence of imidazole as an axial ligand with low to high yields and complete selectivity at room temperature. While the electronic effects of the highly electron-w...

In this simple high-performance thin-layer chromatographic technique for evaluating porphyrin excretion, porphyrins rapidly extracted from urine or feces are separated on reversed-phase octadecylsilyl (C18)-bonded silica thin-layer chromatography plates. We observed > 12 distinct bands of different porphyrins by viewing the plates under long-wave ultraviolet light. Positive screening tests can ...

Urinary porphyrins are separated, according to number of carboxyl groups, in a system consisting of a mu-Bondapak C18 stationary phase and a mobile phase of methanol and aqueous sodium phosphate (pH 3.5) in a linear gradient. The specimen is prepared simply by adjusting the pH of a 5-mL sample to 2.0 and removing solids by centrifugation. The eluted porphyrins are measured fluorometrically. Nat...

Relative bleaching rates of bovine rhodopsin (rod outer segments) in the presence and absence of seven porphyrins and methylene blue were measured under exposure to lambdamax = 675 nm light, using UV-vis spectroscopy. Rate enhancements on the order of up to three times compared to the bleaching of rhodopsin alone where observed. Fluorescence measurements and other data suggests that the porphyr...

Current applications in porphyrin chemistry require the use of unsymmetrically substituted porphyrins. Many current industrial interests in optics and biomedicine require systems with either push-pull (electron-donating and -withdrawing groups) or amphiphilic systems (hydrophobic and hydrophilic groups). In this context we present the class of 5,10-A(2)B(2)-type porphyrins for which two differe...

Plasma porphyrin levels are markedly increased in patients with porphyria cutanea tarda (PCT) associated with end-stage renal disease. Conventional hemodialysis (CHD) with lower blood flow rates (less than 250 mL/min) and cuprophan or cellulose acetate membranes is ineffective in removing significant amounts of porphyrins in this condition. Changes in plasma porphyrin levels and porphyrin clear...