Quinazolinones imidazo

However, perhaps the simplest route to quinazoline derivatives involves the heating of 2-aminobenzamides with formic acid to give 4(3//)-quinazolinones, where the formic acid provides the solvent, the C-2 synthon, and the acid catalysis of the ring-closure step. For example, in the synthesis of the imidazoquinazolinone 798, both the imidazo and pyrimidine rings were formed simply by heating the triamino amide 797 in formic acid for 2h <1996JME918>. 

Substituted imidazo/benzimidazo[2,l- ]quinazolinones could be synthesized from (l//-imidazol-l-yl)[2-(alkylamino)phenyl]methanones and (l//-benzimidazol-l-yl)[2-(alkylamino)phenyl]-methanones catalyzed by CuCl in the absence of hgand using air as the oxidant (Scheme 8.105). The method is tolerant toward functional groups in the substrates, and a range of 5-substituted imidazo/benzimidazo[2,l- ]quinazolinones could be obtained in moderate to good yields. A C(sp )-H bond was activated to form a new C-N bond [179]. 

Scheme 8.105 Synthesis of 5-substituted imidazo/benzimidazo[2,1-6]quinazolinones.

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