Opp-dibenzoporphyrins from benzopyrromethene derivatives
Abstract
Condensation of 1-formyl-3-haloisoindoles with α-free pyrroles in the presence of hydrogen bromide gives the corresponding benzopyrromethene hydrobromides: heating α-halo-α′-methylbenzopyrromethene hydrobromides in o-dichlorobenzene in air provides an economical synthesis of the opp-dibenzoporphyrin system in acceptable yields.