Extended insight into the catalytic activity of boron-doped graphitic carbon nitride for the synthesis of bis-pyrazolyl methanes and pyranopyrazoles.

In this study, boron-doped graphitic carbon nitride (BCN) was successfully prepared via thermal copolymerization of dicyandiamide and boric acid. The structural and morphological features of the as-prepared BCN were thoroughly characterized by various physicochemical techniques such as Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Vis Diffuse Reflectance Spectroscopy (UV-DRS), Brunauer-Emmett-Teller (BET) surface area analysis, and thermogravimetric analysis (TGA). The catalytic performance of BCN was then exploited in the heterogeneous multicomponent synthesis of bis(pyrazolyl)methanes and pyranopyrazoles. The superior catalytic activity of the catalyst stemmed from the B doping and N species located at the B-N-C sites, which impart acid-base dual functionality to the catalyst. These findings substantiate the pioneering utilization of BCN as a robust acid-base cooperative catalyst for the multicomponent synthesis of structurally diverse heterocycles. To the best of our knowledge, this is the first report demonstrating the use of BCN as a dual-function catalyst in MCR chemistry, opening new avenues for green and sustainable organic transformations.