52282-22-1Relevant academic research and scientific papers
One-pot synthesis of correlates by cobalt catalyzed cyclization of formylpyrroles
Paolesse, Roberto,Tassoni, Emanuela,Licoccia, Silvia,Paci, Maurizio,Boschi, Tristano
, p. 55 - 60 (2008/10/08)
2-Formylpyrroles react in the presence of cobalt ions to afford a mixture of porphyrin and corroie cobalt complexes. This is the first example of a single step synthesis of meso-unsubstituted corroie from a monopyrrole. When 3-ethyl-4-methyl-2-formylpyrrole-5-carboxylic acid was used as starting material, Co(Etioporphyrin-I) and a mixture of cobalt correlates were obtained. Chromatographic separation and detailed analysis of the 1H NMR of these compounds allowed their identification as two different etio-like corroles. A possible reaction pathway, explaining their formation is reported. Metals different from cobalt gave only the corresponding porphyrin complex (Ni, Cu). No cyclization at all was observed in the presence of Mn or Rh.
The effect of steric hindrance in the synthesis of corrolates via the cobalt catalyzed cycliztion of 2-(α-hydroxyalkyl)pyrroles
Licoccia, Silvia,Tassoni, Emanuela,Paolesse, Roberto,Boschi, Tristano
, p. 15 - 20 (2008/10/08)
2-(α-hydroxyalkyl)pyrroles react in the presence of cobalt ions leading to the formation of corrolates or porphyrinates as function of the2-substituents. The nature of the cyclic tetrapyrrole obtained can be r elated to the steric hindrance of the substituent present in the starting pyrrole. The presence of cobalt ions is essential to drive the reaction towards the formation of the contracted corrole macroring. When 3-ethyl-4-methyl-2-(α-hydroxybenzyl)pyrrole-5-carboxylic acid is used asstarting material an etio-like cobalt corrolate, i.e. with alternate me thyl and ethyl groups on the β-pyrrolic positions, has been obtained as demonstrated by detailed analysis of the NMR spectrum of the complex. A possible reaction pathway explaining the formation of such a species is reported.
