K2S2O8-enabled one-pot deaminative C–N bond formation for the synthesis of fused benzimidazopurines and benzimidazo-quinazolines

Abstract

We report an unusual, transition metal-free oxidative cyclization strategy for the synthesis of benzoimidazopurine and benzoimidazoquinazoline derivatives via K₂S₂O₈-enabled intramolecular C–N bond formation. The reaction proceeds through an oxidative deamination pathway, wherein the nucleophilic purinyl nitrogen and the departing amino group cooperatively enable efficient cyclization. Notably, 2,6-dichloropurine derivatives delivering benzimidazole-tethered purines wherein solvent DMA acts as an unexpected C1 source, unveiling a unique reactivity mode of purine substrates.