Synthesis and Properties of Macroheterocyclic Compounds of ABAB-type with tert-Butylpyrrole¬pyrazine Fragments

Abstract

Macroheterocyclic compounds (Mc) of ABAB-type can be represented as structural analogues of phthlocyanine, where two opposite isoindole moieties (B) are replaced by aromatic rings (A) derived from aromatic diamines. Since their discovery,[1] these compounds called by Campbel “hemiporphyrazines”[2] are the objects of continuous interest due to their structure particularities[3,4] as well as attractive properties revealed recently: optical limiting, fluorescence, catalysis, devices for keeping information and so on.[5-7] For the moment a number of representatives of this series was synthesized,[8,9] but macrocycles containing pyrazine fragments (B) and those of six-membered aromatic diamines (A) are studied not enough completely. The first two representatives of nonsubstituted macroheterocyclic compounds of this type were described earlier.[10] These compounds were characterized by IR and UV-vis spectroscopies as well as elemental analysis data. Their serious imperfection is a low solubility in common organic solvents, what makes their refinement to be little tedious and constricts a number of methods which could be applied to study their structures and properties. It was established that introduction of bulky tert-butyl groups led to increase of solubility of Mc. [11] Hence the subject of this work is synthesis of Mc of ABAB-type bearing tert-butylpyrazine rings incorporated into macrocyclic core as units (B).