Die Reaktivität des unsubstituierten Porphins

Schlözer, Rüdiger; Fuhrhop, Jürgen‐Hinrich

doi:10.1002/ange.19750871014

Cited by 21 publications

(3 citation statements)

References 5 publications

(1 reference statement)

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“…They were either obtained directly by functionalization of porphine or were isolated as byproducts from condensation reactions in yields of ≤1 %. Examples are 5‐ tert‐ butylporphyrin ( 14 a , 0.3 %),11 formylation (no yield),12a nitration,12b or bromination12c of porphine 1 , or condensation reactions of pyrrole ( 27 )13a or dipyrromethane13b and the corresponding aldehyde. Due to the low yields their characterization is often incomplete.…”

Section: Resultsmentioning

confidence: 99%

MCE enzyme immunoassay for carcinoembryonic antigen and alpha‐fetoprotein using electrochemical detection

Zhang

Cao

et al. 2009

Electrophoresis

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An MCE electrochemical enzyme immunoassay protocol for the determination of carcinoembryonic antigen (CEA) and alpha-fetoprotein (AFP) was reported. Two antigens (Ag), CEA and AFP, were incubated simultaneously with an excess amount of horseradish peroxidase-labeled antibody (Ab(*)). The free Ab(*) and the Ab(*)-Ag complex produced in the solution were first separated through a postcolumn reaction and then traced by the enzyme substrate o-aminophenol. The 3-aminophenoxazine produced in enzyme reaction was detected with downstream amperometric detection. The separations were performed at a separation voltage of +1.4 kV and were completed in less than 60 s. The better analytical performance and distinct miniaturization/portability for MCE at less assay time and sample volume consumption was achieved. The detection limit of CEA and AFP was calculated to be 0.25 and 0.13 ng/mL, respectively. Therefore, MCE could be used as a sensitive and new tool in separation science and offered considerable promise in biological sample analysis or quick clinical diagnosis.

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Section: Resultsmentioning

confidence: 99%

MCE enzyme immunoassay for carcinoembryonic antigen and alpha‐fetoprotein using electrochemical detection

Zhang

Cao

et al. 2009

Electrophoresis

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“…Typical values of p used for t/N are: 1.5 for porphyrin, 1.75 for phlorin, 1.25 for corphin, 1.0 for pyridine and 2 for pyrrole. Two centre replusion integrals were computed using Nishim oto-M ataga relation (M ataga & Nishimoto 1957 examples will illustrate this: bromination of magnesium porphin yields meso tetrabromo porphin without appreciable attack of pyrrolic carbons (Schlozer & Fuhrhop 1975); oxidation of deuteroporphyrin IX dimethylester with lead dioxide leads to the meso tetraoxoporphinogen with no apparent attack of the pyrrole units (Inhoffen, Fuhrhop & v. d. H aar 1966); hydro genation of porphyrins under a variety of conditions gives porphyrinogens with all four bridge carbons reduced and only subsequent attack of pyrrole sites (Fischer & O rth 1940;Chapman et al 1971). Woodward had predicted such regioselectivity from simple valence bond arguments for nucleophilic reactions (Woodward 1962).…”

Section: Porphyrinsmentioning

confidence: 99%

Chemical reactivities of tetrapyrrole pigments: a comparison of experimental behaviour with the results of s.c.f.-π-m.o. calculations

Fuhrhop

Subramanian

1976

Phil. Trans. R. Soc. Lond. B

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Porphyrins are highly sigma-electron donating bases and very weak pi-acids. Hence they increase the electron density on central metal ions, e.g. iron, which leads to the specific reactivity of haem cytochromes, haemoglobin and oxidizing enzymes. The macrocyclic chlorin ligand behaves similarly but to a lesser degree which explains the comparably low oxidation potential of chlorophyll. Phlorins, oxophlorins, oxa- and aza-orphyrins, tetradehydrocorrins, corrins and biliverdins all produce metal complexes which have a similar geometry to that of metalloporphyrins, but their reactivity patterns are different. In contrast to the metalloporphyrins which undergo many fully reversible reactions, these compounds tend to irreversible addition and cleavage reactions. The tetrapyrrole ligands are stronger pi-acids than porphyrins. Results of some recent experimental work and pi-electron s.c.f. calculations are presented in support of these generalizations.

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“…Though there are a number of occurrences where porphyrins of this type are referred to in previous studies, their synthesis either relied on the tedious monofunctionalization 6,7 of porphyrin 1 or they are described as byproducts for which synthesis and/or characterization often remain unclear . Examples include mononitrated and monobrominated porphyrin, (5-formylporphyrinato)copper(II), and tert -butyl- 8a and indolizine-substituted 9 porphyrins among others 8b. Yields for the latter are typically ≤1%.…”

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confidence: 99%

A Practical Synthesis of Meso-monosubstituted, β-Unsubstituted Porphyrins

2002

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[formula: see text] A simple straightforward synthesis for meso-monosubstituted, beta-unsubstituted porphyrins is reported. Porphyrins of this type are easily prepared by condensation of dipyrromethane, pyrrole-2-carbaldehyde, and the desired aromatic or aliphatic aldehyde. The method can be used for a variety of functional groups with yields between 2 and 12%. In most cases, the 5, 15-disubstituted porphyrin is obtained as a second product but can be removed easily.

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Die Reaktivität des unsubstituierten Porphins

Cited by 21 publications

References 5 publications

MCE enzyme immunoassay for carcinoembryonic antigen and alpha‐fetoprotein using electrochemical detection

MCE enzyme immunoassay for carcinoembryonic antigen and alpha‐fetoprotein using electrochemical detection

Chemical reactivities of tetrapyrrole pigments: a comparison of experimental behaviour with the results of s.c.f.-π-m.o. calculations

A Practical Synthesis of Meso-monosubstituted, β-Unsubstituted Porphyrins

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