SYNTHESIS AND STRUCTURAL ASSIGNMENT OF CERTAIN PYRIMIDO[1,2-A]BENZIMIDAZOLE DERIVATIVES

The pyrimido[1,2-a]benzimidazole derivatives compounds 1-8 were synthe sized through cyclocondensation of 2-aminobenzimidazole with the appro priate benzsubstituted benzoylacetone by fusion at 150-170-degrees-C f or 5 h. Quaternary salts compounds 9-22 were obtained by quaternizatio n of compounds 1-8 with dimethyl or diethyl sulfate and subsequent iso lation as the relatively insoluble perchlorate salts. Assignment and c onfirmation of the structures of the newly synthesized compounds were based upon elemental microanalyses and other spectral evidence.