Montmorillonite-Fe3O4 a valuable heterogeneous nanocatalyst for the one-pot synthesis of indeno[1,2-b]indolone derivatives in aqueous media

Fe3O4 magnetic nanoparticles has attracted a lot of attention because of their fundamental application properties in various field such as sensors, clinical use, and high density magnetic recording media [1]. Arc discharge, mechanical grinding, laser ablation, microemulsion, and high temperature decomposition of organic precursors can produce magnetic nanoparticles [2]. Clay minerals such as montmorillonite has large surface area, stable chemical properties, low-cost, well defined layered structure, therefore it has been widely applied in catalyst [3]. Montmorillonite K10 (MMT-K10) is a nanolayered alumina silicate clay can be act as a nanoreactor for the chemical reactions and a drug nanocarrier for pharmaceutical targets. Indeno[1,2-b]indoles are a significant class of heterocyclic compounds because of their potential biological applications [4] and pharmacological studies [5]. A highly efficient one-pot synthesis of Indeno[1,2-b]indoles derivatives 4 has been developed via three component reaction of anilines 1, dimedone 2 and ninhydrin 3 in the presence of recyclable and magnetic organocatalyst MMT@Fe3O4 in aqueous media at 70 oC (Scheme 1).