Access to pyrrole-based heterocyclic compounds via addition of pyrrole to C=C and C=N bonds

Abstract

A series of metal triflate-catalyzed addition reactions of pyrrole to C=C and C=N bonds have been investigated to access pyrrole-based heterocyclic compounds. The addition of pyrrole to different α,β-unsaturated compounds or N-tosyl imines afforded suitable structures for the construction of [5-5] bicyclic systems or porphyrins, respectively. Intramolecular cyclization reactions were applied for the synthesis of pyrrolizine derivatives. In the other reaction mode, intermolecular cyclization reactions gave A4- and trans-A2B2-meso-substituted porphyrins under mild reaction conditions with low scrambling.

Pulsed Discharge Plasma in High-Pressure Environment for Water Pollutant Degradation and Nanoparticle Synthesis

“…Its formula is C 4 H 4 NH, where it consists of a five-membered ring that includes a nitrogen atom. This compound is an electron-rich ring and is easily oxidized [70][71][72]. Figure 6 shows the MALDI-TOF mass spectra of pyrrole after the high-voltage discharge plasma treatment under diverse operating pressures.…”

Selective Synthesis of Tripyrranes, Tetrapyrranes, and Corroles

“…K-10, CuBr and InCl 3 gave 3a in low yields (15-30 % yields; Table 1, Entries 16,18,20,and 21). Comparable yields were obtained if Cu(OTf) 2 , Yb(OTf) 3 , Gd(OTf) 3 , or FeCl 3 were used (Table 1, Entries 3, [12][13][14]. Among these catalysts, Cu-(OTf) 2 formed the desired product 3a in the highest yield (65 %), and it was chosen as the optimal catalyst for the synthesis of dipyrromethanesulfonamides.…”

“…[11] Although significant synthetic progress has been made for meso-substituted corroles, there is still a need for alternative synthetic approaches.Previously, we have successfully developed facile protocols for the synthesis of meso-substituted dipyrromethanes, porphyrins, and [26]hexaphyrin by using tosylimines as effective reagents in the presence of metal triflate catalysts. [12] As part of our ongoing research on oligopyrromethanes and macrocyclic aromatic compounds, herein we present an efficient synthetic methodology for symmetrical or unsymmetrical tripyrranes 4 and tetrapyrranes 5 by starting from dipyrromethanesulfonamides 3. In addition, the use of tetrapyrranes for the synthesis of A 3 as well as trans-A 2 B corroles 6 is described (Scheme 2).…”