2,6-Pyridinedicarboxylic acid as organocatalyst for the synthesis of 1,5-benzodiazepines through one-pot reaction

2,6-Pyridinedicarboxylic acid has been found to be an effective and efficient organocatalyst for the synthesis of 1,5-benzodiazepine derivatives from o-phenylenediamine, β-ketoesters, and aromatic aldehydes by employing one-pot three-component reaction. The catalyst plays a crucial role for the regioselective C–C bond formation at the γ position of β-ketoesters. The salient features of this present protocol are simple reaction procedure, requirement of cost-effective catalyst, good yields, and applicable to a wide range of substrates.