871-78-3Relevant articles and documents
Near-Ambient-Temperature Dehydrogenative Synthesis of the Amide Bond: Mechanistic Insight and Applications
Kar, Sayan,Xie, Yinjun,Zhou, Quan Quan,Diskin-Posner, Yael,Ben-David, Yehoshoa,Milstein, David
, p. 7383 - 7393 (2021/06/30)
The current existing methods for the amide bond synthesis via acceptorless dehydrogenative coupling of amines and alcohols all require high reaction temperatures for effective catalysis, typically involving reflux in toluene, limiting their potential practical applications. Herein, we report a system for this reaction that proceeds under mild conditions (reflux in diethyl ether, boiling point 34.6 °C) using ruthenium PNNH complexes. The low-temperature activity stems from the ability of Ru-PNNH complexes to activate alcohol and hemiaminals at near-ambient temperatures through the assistance of the terminal N-H proton. Mechanistic studies reveal the presence of an unexpected aldehyde-bound ruthenium species during the reaction, which is also the catalytic resting state. We further utilize the low-temperature activity to synthesize several simple amide bond-containing commercially available pharmaceutical drugs from the corresponding amines and alcohols via the dehydrogenative coupling method.
Method for catalytic synthesis of tetraacetylethylenediamine by utilizing supported lithium chloride
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Paragraph 0015; 0017; 0018; 0020; 0022; 0023, (2019/08/20)
The invention provides a method for catalytic synthesis of tetraacetylethylenediamine by utilizing supported lithium chloride. Specifically, the method comprises the following steps: (1) sufficientlymixing a lithium chloride solution, a grinding aid dispersant and a carrier under stirring at room temperature, performing high-temperature drying, and performing grinding to obtain the supported lithium chloride solid acid catalyst; (2) quickly adding anhydrous acetic acid dropwise into ethylenediamine and a conventional catalyst; performing heating, performing a heat preservation reaction, and separating water; and adding acetic anhydride and the lithium chloride catalyst, continuing heating, and performing a reaction; and (3) performing cooling, performing crystallization, performing washing, and performing drying to obtain the tetraacetylethylenediamine. The method provided by the invention utilizes the supported lithium chloride solid acid to catalyze the synthesis of the tetraacetylethylenediamine by the ethylenediamine and an acylating reagent, and the catalyst is beneficial for recovering and can be recycled and has less pollution to the environment; the catalytic efficiency ishigh, the reaction time is effectively shortened, and the product yield can reach 90% or more; and the preparation method of the catalyst is simple, has low costs, and facilitates realizing industrial production and application of the tetraacetylethylenediamine.
Preparation of Polydopamine Sulfamic Acid-Functionalized Silica Gel as Heterogeneous and Recyclable Nanocatalyst for Acetylation of Alcohols and Amines Under Solvent-Free Conditions
Veisi, Hojat,Vafajoo, Saba,Bahrami, Kiumars,Mozafari, Bita
, p. 2734 - 2745 (2018/07/30)
To fabricate SiO2/PDA–SO3H nanocatalyst, a suitable method is designed for the loading of sulfonic acid groups on the surface of polydopamine (PDA)-encapsulated SiO2 nanoparticles. To bridge the gap between heterogeneous and homogeneous catalysis, surface functionalization of silica gel is an elegant procedure. The morphology, structure, and physicochemical features were specified using different analytical techniques including field emission scanning electron microscopy (FESEM), Fourier transformed infrared spectroscopy (FT-IR), high resolution-transmission electron microscopy (HR-TEM), energy dispersive X-ray spectroscopy (EDS), wavelength-dispersive X-ray spectroscopy (WDX), X-ray photoelectron spectroscopy (XPS), and back titration. The SiO2/PDA–SO3H nanoparticles are efficient nanocatalysts for the acetylation of many alcohols, phenols, and amines with acetic anhydride under solvent-free conditions in good to excellent yields. Moreover, the reuse and recovery of the catalyst was shown seven times without detectible loss in activity. Graphical Abstract: [Figure not available: see fulltext.]
