Investigation of porphyrin-forming reactions. Part 3. The origin of scrambling in dipyrromethane + aldehyde condensations yielding trans-A2B2-tetraarylporphyrins

Nucleophilic Aromatic Substitution on Pentafluorophenyl‐Substituted Dipyrranes and Tetrapyrroles as a Route to Multifunctionalized Chromophores for Potential Application in Photodynamic Therapy

“…Condensation reaction of functionalized dipyrranes to trans-A 2 B 2 -porphyrins (A = PFP substituent, B = R-tetrafluorophenyl substituent). However, in particular for the two amino-substituted dipyrranes in addition to the desired A 2 B 2 -porphyrins, other porphyrins were formed as by-products due to 'scrambling´, [36,37] for the dipyrranes 2b and 10a in amounts larger than the desired product (Table 3, entries 1 and 4). This observation is in accordance with a recent publication by Arunkumar and coworkers who also observed large amounts of scrambling products in the condensation reaction of 5-(4-cyanophenyl)-dipyrrane and 8a with BF 3 ·OEt 2 as catalyst.…”

Effects of aldehyde or dipyrromethane substituents on the reaction course leading to meso-substituted porphyrins

“…We previously carried out a series of experiments to gain insight into the course of the condensation. [2][3][4][5] A battery of analytical techniques was employed, which allowed determination of the yields of porphyrinic macrocycles such as the porphyrin, N-confused porphyrin and sapphyrin (by UV-Vis and HPLC), 6 consumption of the aldehyde (by TLC), 7 change in the composition of the mixture of oligomers (by laser desorption mass spectrometry, LD-MS), 2,3 and formation of dipyrrin chromophores (by UV-Vis). 8 These studies, performed with the benchmark reaction of benzaldehyde and pyrrole under a variety of conditions, revealed the complexity of the overall reaction.…”

Synthesis of Metallated (Cu, Pd) Crown Substituted Tetracyclohexenoporphyrins. Crown-Containing Pd Tetrabenzoporphyrin and Its Phosphorescence

“…[24][25][26] Мы предположили, что, вследствие статистического характера распределения заместителей, образование порфиринов с двумя и более краун-эфирными фрагментами будет подавлено в случае использования смеси бензальдегида и формилбензокраун-эфира 2. Облегчению хроматографического разделения, по нашему мнению, могло бы способствовать также введение в него смеси металлированных порфиринов, поскольку в последних отсутствовали бы NH-и N: фрагменты центральной части молекулы порфиринов, взаимодействующие с сорбентом.…”