32570-18-6Relevant articles and documents
Amidosulfonic acid supported on graphitic carbon nitride: novel and straightforward catalyst for Paal–Knorr pyrrole reaction under mild conditions
Azhdari, Asieh,Azizi, Najmedin,Sanaeishoar, Haleh,Tahanpesar, Elham
, p. 625 - 634 (2021/05/12)
A novel heterogeneous acidic catalyst was prepared by in situ immobilization of amidosulfonic acid (NH2SO3H) on graphitic carbon nitride (g-C3N4) under hydrothermal conditions. The textural morphology of NH2SO3H/g-C3N4 nanocomposite was characterized via powder X-ray diffraction, FT-IR, TGA, EDX, and scanning electron microscopy. The spatial arrangement of the amidosulfonic acid on the surface of g-C3N4 leads to the construction of a unique solid acid structure, resulting in a substantial enhancement of catalytic activity toward a high efficient preparation of pyrroles by Paal–Knorr reaction. The reactions undergo completion readily with good to excellent yields, with simple purification in an environmentally friendly manner. The NH2SO3H/g-C3N4 nanocomposite can be readily recycled, and no noteworthy reduction in the catalytic activity detected after four runs. Graphic abstract: [Figure not available: see fulltext.]
A New Green and Efficient Br?nsted: Lewis Acidic DES for Pyrrole Synthesis
Shaibuna,Theresa, Letcy V.,Sreekumar
, p. 2359 - 2372 (2018/06/20)
Abstract: Deep eutectic solvents (DESs) are fluids composed of different Lewis or Br?nsted acids and bases, generally acknowledged as new analogues to ionic liquids (ILs), because of their similar characteristics, but with more advantages related to preparation cost, environmental impact etc. Their preparation involve the simple mixing of two components generally with moderate heating that are inexpensive, non-toxic, biodegradable and the resulting mixture is capable to overcome the drawbacks of conventional organic solvents and ILs. Chemical reactions with these materials are significantly less hazardous and they can act as catalysts as well as reaction media. Here, three new DESs based on ZrOCl2·8H2O in combination with urea, ethylene glycol and glycerol are introduced. Physicochemical properties like phase behaviour, Freezing point, density, viscosity, thermal stability and miscibility properties in common solvents are determined. In addition, a new method for the determination of acidity of DESs having both Br?nsted and Lewis sites is also introduced in this work. A convenient synthesis of pyrrole through Paal–Knorr reaction is reported using a variety of amines which are used to establish the importance of this catalyst in organic reactions. The products are analysed by GC–MS, 1H NMR and 13C NMR. By comparing the three DESs, DES 1 (formed from ZrOCl2·8H2O with urea) has the lowest density, viscosity, highest acidity and thermal stability. It was shown to be an excellent green catalyst for Paal–Knorr reaction. Reusability of the catalyst was also achieved up to 4 runs, without significant loss in its catalytic activity. Graphical Abstract: [Figure not available: see fulltext.]
The application of iron (III) phosphate in the synthesis of N-substituted pyrroles
Samadi, Marjan,Behbahani, Farahnaz K.
, p. 2881 - 2884 (2015/11/03)
A variety of N-substituted pyrroles have been prepared by reacting 2,5-hexadione with amines or diamines in the presence of iron (III) phosphate at room temperature under solvent-free conditions. The experiment protocol features simple operations, and the products are isolated in high yields (88-99%).
