Sulfated polyborate: a new and eco-friendly catalyst for one-pot multi-component synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones via Biginelli reaction

Abstract

A highly efficient and improved synthetic methodology for the preparation of 3,4-dihydropyrimidin-2(1H)-one derivatives in good to excellent yield via Biginelli reaction of β-ketoesters/β-diketone, urea/thiourea and various aldehydes using new, efficient and recyclable sulfated polyborate catalyst under the solvent-free condition is reported.

Sulfated polyborate: A mild, efficient catalyst for synthesis of N-tert-butyl/N-trityl protected amides via Ritter reaction

“…The catalyst was prepared and characterized by various analytical techniques such as potentiometric analysis, Fourier transform infrared spectroscopy (FTIR), X-ray Sulfated polyborate catalyzed N-tert-butyl/N-trityl protected amides 417 diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDAX). 44 Recently, we have reported an efficient sulfated polyborate as a catalyst for one-pot multicomponent synthesis of 3,4-dihydropyrimidin-2(1H )-ones/thiones via Biginelli reaction, 44 synthesis of α-aminophosphinates via Kabachnik-Fields reaction, 45 synthesis of quinoxalines, 46 Hantzsch 1,4-dihydropyridines, 47 and Kindler reaction 48 all under solvent-free conditions. Its ease of preparation, high stability, mild acidity, and reusability prompted us to explore its potential to catalyze other useful reaction transformations.…”

“…The sulfated polyborate catalyst was prepared from boric acid and characterized as reported in the literature. 44…”

Rapid, efficient and eco-friendly procedure for the synthesis of quinoxalines under solvent-free conditions using sulfated polyborate as a recyclable catalyst

“…The catalyst was prepared and characterized by various analytical techniques such as potentiometric analysis, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) energy dispersive X-ray spectroscopy (EDAX). 60…”

Expeditious and efficient synthesis of Strecker’s α-aminonitriles catalyzed by sulfated polyborate

“…[47][48][49][50][51][52] Its easy preparation, mild acidity, eco-friendliness, and reusability have encouraged us to investigate its potential to catalyze many other useful organic transformations. Therefore, inspired by our previous finding, herein we report a rapid, efficient and green method for synthesis of α-aminonitriles via Strecker reaction using aldehyde, amine, and TMSCN in the presence of a sulfated polyborate as a recyclable catalyst under solvent-free conditions.…”