Fe3o4-Sahpg-Pd(0)Nanoparticles: A Ligand-Free And Low Pd Loading Quasiheterogeneous Catalyst Active For Mild Suzuki-Miyaura Coupling And C-H Activation Of Pyrimidine Cores

This paper reports a green magnetic quasiheterogeneous efficient palladium catalyst in which Pd(0)nanoparticles have been immobilized in self-assembled hyperbranched polyglycidole (SAHPG)-coated magnetic Fe(3)O(4)nanoparticles (Fe3O4-SAHPG-Pd-0). This catalyst has been used for effective ligandless Pd catalyzed Suzuki-Miyaura coupling reactions of different aryl halides with substituted boronic acids at room temperature and in aqueous media. Herein, SAHPG is used as support; it also acts as a reducing agent and stabilizer to promote the transformation of Pd(II)to Pd(0)nanoparticles. Also, this environmental friendly quasiheterogeneous catalyst is employed for the first time in the synthesis of new pyrimido[4,5-b]indoles via oxidative addition/C-H activation reactions on the pyrimidine rings, which were obtained with higher yield and faster than when Pd(OAc)(2)was used as the catalyst. Interestingly, the above-mentioned catalyst could be recovered in a facile manner from the reaction mixture by applying an external magnet device and recycled several times with no significant decrease in the catalytic activity.