A Highly Active Catalyst 2,4,6‐Tris (di‐4‐chlorobenzamido)‐1,3,5‐triazine Palladium (II) Chloride for the Green Synthesis of Substituted Dihydrobenzo[b]thiophene in Ionic Liquid

Abstract

The palladium‐metallodendrimer (Pd‐MD) 2,4,6‐tris (di‐4‐chlorobenzamido)‐1,3,5‐triazine palladium (II) chloride was synthesized by the reaction of substituted triazine, substituted benzoyl chloride, and (Ph3P)2PdCl2 in DMF at 100 °C. This Pd‐MD was characterized by FTIR, 1H NMR, 13C NMR, Scanning Electron Microscopy (SEM), Energy Dispersive X‐ray (EDX), mass spectrometry, X‐ray photoelectron spectroscopy (XPS), elemental analysis, Thermogravimetric analysis (TGA), and Differential scanning calorimetry (DSC) methods. This catalyst was successfully applied for the green synthesis of different substituted alkyl 2,3‐dihydrobenzo[b]thiophene‐2‐carboxylates in ionic liquid tetra‐n‐butylammonium bromide (TBAB) solution at 120 °C for 2.5 hours with a good to an excellent percentage of yields (75 % to 96 %). Importantly, this homogeneous catalytic system was easily recoverable and reusable at least five times without a significant loss of activity.