One-pot multicomponent synthesis of thieno[2,3- b ]indoles catalyzed by a magnetic nanoparticle-supported [Urea] 4 [ZnCl 2 ] deep eutectic solvent.

In this study, we have developed the synthesis of thieno[2,3- b ]indole dyes via a multicomponent reaction of cheap and available reagents such as sulfur, acetophenones, and indoles using a magnetic nanoparticle-supported [Urea] 4 [ZnCl 2 ] deep eutectic solvent as a green catalyst. The synthesis of a series of diversely functionalized thieno[2,3- b ]indole has been successfully performed in a one-pot reaction. Among a total of 25 compounds synthesized, there are 21 new compounds with full characterization such as FT-IR, 1 H and 13 C NMR, HRMS (ESI). Due to the deep eutectic solvent coated surface of the magnetic nanoparticles, the catalyst could be recovered by an external magnet and reused in five consecutive runs without a considerable decrease in catalytic activity.