One-pot synthesis of 1,3-diazaheterocycles via hydroxylamine hydrochloride activation of anthranilamide/phenylenediamines and DMF derivatives

The development of sustainable methods is highly desirable in synthetic organic chemistry. In this regard, we report hydroxylamine hydrochloride mediated, one-pot synthesis of 1,3-diazaheterocycles using anthranilamide or o-phenylenediamine with amides via transamidation under solvent free condition at 120–140 °C for 8–14 h. This method proceeds smoothly under metal- and oxidant-free conditions exhibited broad substrate scope with reference to both diamines derivatives and amides, resulted in corresponding 4(3H)-quinazolinone (3) and benzimidazoles (5&6) (∼47 examples) in good to excellent yield (56–96 %). As an efficient and environmentally friendly access to a broad range of 4(3H)-quinazolinones and benzimidazoles and the synthetic utility of this method was demonstrated by gram-scale operation, achieved >90 % yield.