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

摘要

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 ℃.This Pd-MD was characterized by FTIR,~1HNMR,~(13)CNMR,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℃ 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.