2683-82-1Relevant articles and documents
Surprising Outcomes of Classic Ring-Expansion Conditions Applied to Octaethyloxochlorin, 3. Schmidt-Reaction Conditions
Li, Ruoshi,Zeller, Mathias,Bruhn, Torsten,Brückner, Christian
, p. 1835 - 1842 (2017/04/21)
The Schmidt reaction (treatment of a ketone with sodium azide and a mineral acid) is an alternative to the Beckmann rearrangement to expand a cyclic ketone to a lactam. However, when applied toward the conversion of a synthetic porphyrin into a derivative containing a nonpyrrolic building block, this approach failed to generate the expected lactam. Instead, by using sulfuric acid as a catalyst, a novel heptaethyl-2-hydroxy-chlorin-3-one was formed, structurally characterized, and its mechanism of formation deduced. The work demonstrates how the extraordinary structural stability of the porphyrin macrocycle redirects the reactivity patterns of classic ring-expansion reactions. By using hydrochloric acid as a catalyst, a somewhat regioselective chlorination of the meso-positions of the oxochlorin was observed. The halogenation sites were determined spectroscopically and by X-ray crystallography of selected derivatives. The regioselectivity of the halogenation was computationally rationalized. This method is superior to alternative halogenation methods for the regioselective generation of 5-chloro-, 10-chloro-, and 5,10-dichlorooxochlorins.
Synthesis of a Family of Highly Substituted Porphyrin Thioethers via Nitro Displacement in 2,3,7,8,12,13,17,18-Octaethyl-5,10,15,20-tetranitroporphyrin
Kielmann, Marc,Flanagan, Keith J.,Norvai?a, Karolis,Intrieri, Daniela,Senge, Mathias O.
, p. 5122 - 5134 (2017/05/24)
A series of highly substituted porphyrin thioethers was synthesized from 2,3,7,8,12,13,17,18-octaethyl-5,10,15,20-tetranitroporphyrin (H2OETNP). The reactions proceeded via a SNAr mechanism with a broad range of aromatic thiols in the presence of a base. This is a rapid way to prepare a large variety of meso-substituted porphyrins from only one precursor. Single crystal X-ray analysis revealed that these new porphyrin thioethers are highly distorted, exhibiting conformational properties that are distinctive of both meso-sulfur substitution and steric overcrowding in general. Additionally, denitration of H2OETNP under basic conditions was investigated, yielding products of stepwise desubstitution. This allowed a comparative X-ray crystallographic study to delineate the successive structural effects of an increasing degree of nitro substitution in the complete series of nitro-substituted octaethylporphyrins.
Paley's watchmaker analogy and prebiotic synthetic chemistry in surfactant assemblies. Formaldehyde scavenging by pyrroles leading to porphyrins as a case study
Alexy, Eric J.,Hintz, Carl W.,Hughes, Hubert M.,Taniguchi, Masahiko,Lindsey, Jonathan S.
, p. 10025 - 10031 (2015/10/12)
The formation of elaborate molecules is regarded as an essential first step in prebiotic chemistry, but how such transformations could spontaneously occur, particularly in dilute aqueous conditions, remains poorly understood. Here, micromolar concentrations of a 3,4-dialkylpyrrole and excess formaldehyde in aqueous micellar solution (pH 7) at 25 or 50 °C were found to give good yield (up to 40%) of the lipophilic octaalkylporphyrin. The reaction occurs despite a mean occupancy number of ～0.1 pyrrole molecules/micelle, and 1 of 10 000 micelles initially containing the requisite 4 pyrrole molecules to form the porphyrin assuming a (random) Poisson distribution. Yields of up to 13% were observed in large, unilamellar phosphatidylcholine vesicles, wherein there are ～15 000 pyrrole molecules per vesicle membrane. Double-labeling crossover experiments (of 3,4-diethylpyrrole and 3,4-dimethylpyrrole) examined by mass spectrometry revealed facile exchange processes of reactive constituents among both micelle and vesicle surfactant assemblies. Together, the exchange of pyrrolic reactants among micelles and the thermodynamic driving force for tetrapyrrole formation overcome the apparent statistical odds against reaction. The fruitful exchange, accumulation and reaction of minute quantities of reactants in aqueous-surfactant assemblies suggest a general means for formation of prebiotically valuable constituents, even when the statistical odds at the outset are overwhelmingly improbable.
Syntheses of highly distorted meso-trifluoromethyl-substituted β-octaalkylporphyrins
Suzuki, Masaaki,Ishii, Shuto,Hoshino, Tyuji,Neya, Saburo
supporting information, p. 1563 - 1565 (2015/02/19)
Treatment of 5,5′-d icarboxy-3,3′,4,4′-tetraalkyl-2,2′-dipyrromethanes with trifluoroacetic acid and subsequent oxidation resulted in formation of meso-trifluoromethy l-substituted β-octaalkylporphyrins. The structura l characterizations and the spectrosc
The exhaustive reduction of formylporphyrins to methylporphyrins using dimethylformamide/water as reductant under microwave irradiation
Fletcher, Sarah J.,Harper, Shannon R.,Arnold, Dennis P.
, p. 200 - 208 (2014/05/20)
The reduction of meso-formyl derivatives of 5,15-diaryl- and 5,10,15-triphenylporphyrin (and their nickel(II) complexes) to the corresponding meso-methyl porphyrins is achieved in high yield by microwave heating of the substrate in dimethylformamide (DMF)
Microwave-assisted Piloty-Robinson synthesis of 3,4-disubstituted pyrroles
Milgram, Benjamin C.,Eskildsen, Katrine,Richter, Steven M.,Scheidt, W. Robert,Scheidt, Karl A.
, p. 3941 - 3944 (2008/02/01)
(Chemical Equation Presented) The synthesis of N-acyl 3,4-disubstituted pyrroles can be accomplished directly from hydrazine and an aldehyde via a Piloty-Robinson pyrrole synthesis. The use of microwave radiation for the cyclization and pyrrole formation
Phenyl-substituted porphyrins. 1. Synthesis of meso-phenyl-substituted porphyrins
Syrbu,Lyubimova,Semeikin
, p. 1262 - 1270 (2007/10/03)
A method was developed for the synthesis of a series of meso-phenyl-substituted octaalkylporphyrins with various numbers of phenyl groups at various positions. Some of their properties were studied.
Dissociation kinetics of copper and cobalt complexes with sterically distorted porphyrins
Kuvshinova,Kuz'min,Dudkina,Pukhovskaya,Semeikin,Golubchikov
, p. 133 - 136 (2007/10/03)
The dissociation kinetics of the cobalt and copper complexes with octaethylporphyrin, its 5-phenyl, 5,15-diphenyl, and 5,10,15,20-tetraphenyl derivatives, and dodecaphenylporphyrin in acetic acid with small additions of trifluoroacetic acid were studied. In this series of complexes, the steric distortion of the tetrapyrrole macrocycle sequentially increases, which results in a regular decrease in the kinetic stability of the metal porphyrins: The dissociation rate increases by three orders of magnitude.
Tripyrrin - The missing link in the series of oligopyrrolic ligands
Broering,Brandt
, p. 499 - 500 (2007/10/03)
The first derivative of the hitherto elusive tripyrrin 2 was prepared and characterized; the X-ray structural analysis of its trifluoracetato-palladium(II) complex 7 displays a highly flexible N3 ligand.
Structure-stability relationships of phthalocyanine copper complexes
Sokolova,Lomova,Klueva,Suslova,Mayzlish,Shaposhnikov
, p. 775 - 785 (2007/10/03)
The influence of NO2, Br, and COOH function substituents in various positions of Cu(II)Pc on the reactivity of the latter concerning the dissociation of the metal - nitrogen bonds in proton donor solvents is discussed.
