Sulfated polyborate catalyzed Kindler reaction: a rapid, efficient, and green protocol

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.…”

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.…”

Condensation of Amines with S-Methyl Thiouronium Salts: Another Entry for the Synthesis of Amidines

“…Thus, heating an aldehyde 4 with piperidine/morpholine in the presence of sulfur at 120 °C for three to four hours furnished thioamides 5 under solvent free conditions (Scheme 4 ). 39 Refluxing thioamides 5 with methyl iodide in methanol for one to two hours furnished the S -methyl thiouronium salts 1 in quantitative yields. 40…”