Synthesis of benzimidazolones via CO2 fixation and N-phenyl formamides using formic acid in presence of zinc embedded polymer complex

Abstract

The use of formic acid or carbon dioxide as a C1 source for the synthesis of medicinally, as well as industrially, imperative compounds has been gaining predominant attention of synthetic chemists in the current era. This article describes the synthesis of an eco-friendly low-cost modified Merrifield supported zinc catalyst [Zn(Meri-Ald-Py)]. Characterization of the newly synthesized catalyst was performed properly by various instrumental techniques like CHN analysis, elemental mapping, FTIR, Energy Dispersive X-ray analysis, FESEM, TGA, PXRD, N₂ adsorption–desorption and AAS (atomic absorption spectroscopy). Benzimidazolone derivatives were synthesized quite efficiently through CO₂ fixation in o-phenylenediamine in the presence of a Zn(Meri-Ald-Py) catalyst at 110 °C using 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) under atmospheric pressure. Furthermore, the synthesized catalyst can effectively produce various N-formylated products from aniline derivatives by utilizing formic acid within a very short reaction duration (4.5–20 minutes) at 30 °C. Above all, the catalyst is highly heterogeneous in nature and can be used proficiently in several successive cycles.