A PASE Approach to the Synthesis of Benzimidazopurines as Polycondensed Purine Derivatives
Keyword(s):
X Ray
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A highly efficient PASE approach to a new class of polycyclic purine derivatives has been proposed. The strategy includes a consecutive reduction, auto-aromatization, and heterocyclization of the initial nitrobenzimidazopyrimidines obtained by a three-component condensation. It was shown that reduction of nitrobenzimidazopyrimidines by metals in acidic media was more efficient than heterogeneous hydrogenation. Novel derivatives of benz[4,5]imidazo[1,2-a]purines were obtained in good yields and the proposed structure was confirmed by X-ray crystal structure analysis. The obtained convergent benzimidazopurines combine two relevant medicinal chemistry scaffolds – benzimidazole and purine.