5-Substituted dipyrromethane analogues (8), (23) and (25) were synthesized by the reaction of 2-vinylpyrroles, 2-vinylthiophene or 2-vinylbenzenes with excess pyrrole in the presence of Lewis acids. Accordingly, tripyrromethane analogues could be obtained by starting with 2,5-divinyl thiophene or 2,6-divinylbenzenes. The reaction usually gave moderate yields and catalyst-dependent was seen in some cases. The reaction is compatible with other reported dipyrromethane syntheses and could be applied for the construction of unusual porphyrins.
Bibliographical noteFunding Information:
This work was supported by a grant from the Korea Science and Engineering Foundation (KOSEF) grant (R01-2006-000-10001-0) funded by the Korean government (MOST). Vascular System Research Center (VSRC) and Central Instrumentation Facility at KNU are acknowledged for support.