Phenanthroline-functionalized porous aromatic framework: An efficient heterogeneous catalyst for the tandem reaction of 2-iodoanilines and isothiocyanates in water

A phenanthroline-functionalized porous aromatic framework (Phen-PAF) was synthesized by the Sonogashira reaction between 1,3,5-tris-(4-ethynylphenyl)benzene (TEB) and 3,8-dibromo-1,10-phenanthroline (DPHEN). Phen-PAF was demonstrated to have highly catalytic effect on the tandem reaction between 2-iodoanilines and isothiocyanates, leading to a series of 2-aminobenzothiazole derivatives in good to excellent yield (80-99%). The reaction was environmentally friendly for utilizing water as solvent under mild heating conditions. More importantly, Phen-PAF catalyst can be recycled by simple filtration and drying. Phen-PAF kept its robust chemical structure and catalytic activity for at least 5 catalytic cycles, which was in accordance with sustainable chemistry. Phen-PAF was, what has been reported so far, the first organic porous heterogeneous catalyst towards the tandem reaction of 2-iodoanilines and isothiocyanates with environmentally friendly solvent, which may enlighten us to design more function-oriented PAF materials as heterogeneous catalysts towards various organic reactions.