One-Pot Three Component Synthesis of 2,3-Dihydro-1H-1,5- benzodiazepines by a Magnetically Recyclable Nanocatalyst Fe3O4@SiO2- Cu-salen

Benzodiazepines and their polycyclic derivatives are an important class of bioactive compounds.Many functionalized benzodiazepines are widely used as anti-convulsant, antianxiety,analgesic, sedative, anti-depressive and hypnotic agents. These compounds also,finding applications as dyes for acrylic fibers and anti-inflammatory agents. 1,5-Benzodiazepines are key intermediates for the synthesis of various fused ring compoundssuch as triazolo-, oxadiazolo- and oxizino-diazepines [1]. Due to their broad spectrum of biologicalactivity, these compounds received a lot of attention towards their synthesis. The generalmethod for the synthesis of 1,5-benzodiazepines involves an acid-catalyzed condensationof o-phenylenediamines with α,β-unsaturated carbonyl compounds or β-halo ketones or ketones.Many reagents have been utilized for this reaction including polyphosphoric acid-SiO2,BF3·OEt2, NaBH4, Yb(OTf)3, MgO-POCl3, and more recently acetic acid under microwaveconditions [2]. In continuation of our research towards the synthesis of biologically importantmolecules in this study various 1,5-benzodiazepine derivatives were synthesized by the condensationreaction of o-phenylenediamine with various ketones using the Fe3O4@SiO2-Cusalen[3] as an efficient, heterogeneous magnetically recyclable catalyst (Fig. 1).