18494-86-5Relevant articles and documents
A New Green and Efficient Br?nsted: Lewis Acidic DES for Pyrrole Synthesis
Shaibuna,Theresa, Letcy V.,Sreekumar
, p. 2359 - 2372 (2018)
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.]
Xanthan sulfuric acid as an efficient, green, biodegradable, and recyclable solid acid catalyst for one-pot synthesis of N-substituted pyrroles under solvent-free conditions at room temperature
Rahmatpour, Ali
, p. 491 - 495 (2012)
A new, green, and efficient method for synthesis of a variety of N-substituted pyrroles from condensation reactions of 2,5-hexanedione with amines or diamines using xanthan sulfuric acid as a biosupported and reusable ecofriendly catalyst under solvent-free conditions at room temperature is described. The use of a nontoxic, inexpensive, easily available, and reusable biosupported proton source catalyst under solvent-free conditions makes this protocol practical, environmentally friendly, and economically attractive.
A simple synthesis of pyrroles catalyzed by acidic resin under solvent-free condition
Yuan, Shizhen,Li, Zhen,Xu, Ling
, p. 446 - 448 (2010)
A simple and effective Paal-Knorr condensation of 2, 5-hexanedione with most amines has been carried out at room temperature under solvent-free condition. The pyrroles were obtained in high yields and in short reaction times.
Simple synthesis of pyrroles under solvent-free conditions
De, Surya K.
, p. 2768 - 2774 (2008)
Paal-Knorr condensation of 2,5-hexadione with primary amines in the presence of a catalytic amount of praseodymium(III) trifluoromethanesulfonate under solvent-free conditions has been accomplished with an excellent yield. This method is a very easy, rapid, and high-yielding reaction for the synthesis of N-substituted pyrrole derivatives. Copyright Taylor & Francis Group, LLC.
A convenient synthesis of pyrroles catalyzed by acidic resin under solvent-free condition
Yuan, Shi Zhen,Liu, Jin,Xu, Ling
, p. 664 - 668 (2010)
A convenient and effective Paal-Knorr condensations of 2,5-hexanedione with most amines have been carried out at room temperature under solvent-free condition. Macroporous strongly acidic styrol resin (D001) as a novel, efficient, cost-effective, and reusable solid acid catalyst for the synthesis of pyrroles under the same conditions. The pyrroles were obtained in high yields in short reaction times.
Cellulose sulfuric acid as a biodegradable and recoverable solid acid catalyst for one pot synthesis of substituted pyrroles under solvent-free conditions at room temperature
Rahmatpour, Ali
, p. 80 - 83 (2011)
A new and efficient method for the preparation of N-substituted pyrroles from one-pot condensation reaction of 2,5-hexandione with amines and diamines in the presence of cellulose sulfuric acid (CSA) as a bio-supported catalyst at room temperature under solvent-free conditions is presented. This new protocol has the advantages of easy availability, stability, reusability and eco-friendly of the catalyst, high to excellent yields, simple experimental and work-up procedure.
Synthesis of Fe3O4@L-proline@SO3H as a novel and reusable acidic magnetic nanocatalyst and its application for the synthesis of N-substituted pyrroles at room temperature under ultrasonic irradiation and without solvent
Behbahani, Farahnaz K.,Shokri, Fatemeh
, (2021/08/18)
N-Substituted pyrroles have been prepared in high isolated yields (65–90%) by the reaction of hexane-2,5-dione with amines or diamines in the presence of Fe3O4@L-proline@SO3H at ambient temperature under ultrasonic irradiation and without solvent. The experimental procedure involves simple operations, and the products are readily separated by external magnet. The same reaction of hexane-2,5-dione with amines containing electron-acceptor substituents, such as 4-nitroaniline, resulted in fair yields of pyrrole derivatives.
Superbase-promoted multi-molecular acetylene/arylamine self-organization to 1-arylpyrroles
Schmidt, Elena Yu.,Semenova, Nadezhda V.,Ivanova, Elena V.,Bidusenko, Ivan A.,Trofimov, Boris A.
, p. 109 - 111 (2020/02/29)
A new superbase-promoted reaction of acetylene involves self-organization of its three molecules with one molecule of arylamine in KOH/DMSO system to afford 1-aryl-2,5- dimethylpyrroles in up to 63% yields. The key step of this reaction cascade is assumed to be the nucleophilic addition of acetylene to the C = N bond of the intermediate aldimine (aza-Favorsky reaction).
