5044-26-8Relevant academic research and scientific papers
A convenient approach for the synthesis of substituted pyrroles by using phosphoric acid as a catalyst and their photophysical properties
Ai, Liankun,Ibrahim, Yusuf Ajibola,Li, Baolin,Li, Jiahui
, (2021/12/21)
Twenty-three new pyrrole compounds aside from six knowns, including the synthetically challenging tetra- and penta-substituted pyrroles from the corresponding 1,4-dicarbonyl through Paal-Knorr synthesis in the presence of 5% phosphoric acid as the catalyst. Our method is noteworthy for cheap catalyst, uncomplicated experimental setup under air atmosphere, scalability, and excellent yields. The fluorescence of some selected pyrroles was investigated in dilute solution, and we found that all novel pyrroles emit strong blue fluorescences with considerable Stokes shifts.
One-pot synthesis of cyclohexylamine and: N -aryl pyrroles via hydrogenation of nitroarenes over the Pd0.5Ru0.5-PVP catalyst
Chaudhari, Chandan,Sato, Katsutoshi,Ikeda, Yasuyuki,Terada, Kenji,Abe, Naoya,Nagaoka, Katsutoshi
supporting information, p. 9743 - 9746 (2021/06/15)
The direct synthesis of cyclohexylamine via the hydrogenation of nitrobenzene over monometallic (Pd, Ru or Rh) and bimetallic (PdxRu1-x) catalysts was studied. The Pd0.5Ru0.5-PVP catalyst was the most effective catalyst for this reaction. The catalyst can be reused and applied for the synthesis of N-aryl pyrroles and quinoxalines from nitrobenzenes.
A New FXR Ligand Chemotype with Agonist/Antagonist Switch
Helmst?dter, Moritz,Vietor, Jan,Sommer, Jana,Schierle, Simone,Willems, Sabine,Kaiser, Astrid,Schmidt, Jurema,Merk, Daniel
supporting information, p. 267 - 274 (2021/02/20)
Therapeutic modulation of the bile acid-sensing transcription factor farnesoid X receptor (FXR) is an appealing strategy to counteract hepatic and metabolic diseases. Despite the availability of several highly potent FXR agonists structural diversity of FXR modulators is limited, and new ligand scaffolds are needed. Here we report structure-activity relationship elucidation of a new FXR modulator chemotype whose activity can be tuned between agonism and antagonism by two minor structural modifications. Starting from a weak FXR/PPAR agonist, we have developed selective FXR activators and antagonists with nanomolar to low-micromolar potencies and binding affinities. The new FXR ligand chemotype modulates the FXR activity in the native cellular setting, is endowed with favorable metabolic stability, and lacks cytotoxicity. It valuably expands the collection of FXR modulators as a new scaffold for FXR-targeted drug discovery.
Crystalline salicylic acid as an efficient catalyst for ultrafast Paal–Knorr pyrrole synthesis under microwave induction
Aghapoor, Kioumars,Mohsenzadeh, Farshid,Darabi, Hossein Reza,Sayahi, Hani
, (2021/04/19)
Abstract: In this study, the viability of a wide range of crystalline aromatic and aliphatic carboxylic acids as organocatalysts has been investigated for solvent-free Paal–Knorr pyrrole synthesis under microwave activation. Among these potential catalysts, crystalline salicylic acid proved to be a remarkable catalyst because its efficiency remained high even under low microwave power irradiation or a shorter reaction time for the model reaction. The outstanding catalytic activity of salicylic acid allowed the Paal–Knorr cyclocondensation with a turnover frequency up to 1472?h?1 which is unique in the context of a metal-free homogeneous catalysis. The attractive feature of this organocatalyst is its assistance in ultrafast pyrrole synthesis with no risk of metal contamination. Graphic abstract: [Figure not available: see fulltext.] Synopsis: A green and expeditious protocol for the synthesis of 2,5-dimethylpyrroles via combination of salicylic acid as catalyst (in its solid state) and microwaves has been introduced.
Facile fabrication of porous magnetic covalent organic frameworks as robust platform for multicomponent reaction
Azizi, Najmedin,Heidarzadeh, Fatemeh,Farzaneh, Fezeh
, (2021/07/26)
The design of cheap yet efficient nanoporous magnetic catalysts for the environmentally benign process's widespread application is an extremely attractive, challenging chemical research field. A novel porous magnetic covalent organic framework was prepared by the condensation reaction of melamine and terephthaladehyde on the surface of 3,4-dihydroxybenzaldehyde coated magnetic Fe3O4 nanoparticles COF@Fe3O4 under hydrothermal conditions for the first time. The high surface area magnetic COF could exhibit superior catalytic activity for sustainable synthesis of trisubstituted and tetrasubstituted imidazoles and pyrroles in good to excellent yields in PEG as solvent under environmentally friendly, ambient conditions and making the overall process economical, efficient, and green. The retrievable catalyst in PEG is general and applicable to a broad substrate scope and functional group compatibility. The structure and morphology of the COF@Fe3O4 were characterized by FTIR, XRD, EDX, and SEM spectroscopy. The COF@Fe3O4 magnetic catalyst was recovered by an external magnet and used for several cycles without significant catalytic activity loss.
Naturally occurring organic acids for organocatalytic synthesis of pyrroles via Paal–Knorr reaction
Mohsenzadeh, Farshid,Darabi, Hossein Reza,Alivand, Mahsa,Aghapoor, Kioumars,Balavar, Yadollah
, p. 5255 - 5262 (2020/09/09)
Abstract: In this study, common naturally occurring organic acids, namely oxalic, malonic, succinic, tartaric and citric acid (as safe, inexpensive, and biodegradable organocatalysts), have been employed for Paal–Knorr pyrrole synthesis. The organocatalyzed reaction proved to be effective in ethanol at 60?°C. However, the reaction rate is mainly dominated by the nature and position of functional groups on the aromatic ring of substrate. This metal-free procedure tolerates a series of functional groups and should be considered as an asset to the pharmaceutical industry since no metal contamination could take place during the synthesis of pyrrole scaffolds. Graphic abstract: [Figure not available: see fulltext.].
Rhenium-Catalyzed Dehydrogenative Coupling of Alcohols and Amines to Afford Nitrogen-Containing Aromatics and More
Mastalir, Matthias,Glatz, Mathias,Pittenauer, Ernst,Allmaier, Günter,Kirchner, Karl
supporting information, p. 1116 - 1120 (2019/05/16)
An efficient synthesis of quinolines, pyrimidines, quinoxalines, pyrroles, and aminomethylated aromatic compounds catalyzed by a well-defined Re(I) PNP pincer complex is described. All reactions proceed with liberation of dihydrogen and elimination of water. Under optimized reaction conditions a wide range of organic functional groups are tolerated. This study demonstrates that rhenium catalysts are performing extremely well in dehydrogenative processes with considerably lower catalyst loadings and shorter reaction times when compared to analogous Mn(I) complexes.
Grinding solvent-free paal-knorr pyrrole synthesis on smectites as recyclable and green catalysts
Marvi, Omid,Nahzomi, Hossein Taherpour
, p. 139 - 147 (2018/04/23)
An environmentally benign method for the synthesis of N-substituted pyrroles from one-pot solvent-free condensation reaction of 2,5-hexanedione with various primary amines (Paal-Knorr pyrrole synthesis) on smectite clays as green and reusable heterogeneous Lewis acid catalysts is presented. The use of nontoxic, inexpensive, easily available and reusable catalysts under solvent-free conditions make this protocol practical, environmentally friendly and economically attractive.
Novel and highly efficient preparation of pyrroles using supported ionic liquid ILCF3SO3@SiO2 as a heterogeneous catalyst
Liu, Yang,Hu, Yu Lin
, p. 1033 - 1040 (2018/05/22)
Abstract: A supported ionic liquid ILCF3SO3@SiO2 was synthesized and used as a highly efficient catalyst in the Paal–Knorr reaction for the preparation of pyrroles. The heterogeneous catalyst could be easily recovered and recycled for five times without noticeable loss of catalytic activity. Also a possible reaction mechanism is provided.
Bio-based material as medium, mild and reusable catalyst for paal–knorr pyrrole synthesis with and without ultrasonic irradiation
Sharma, Abha,Kalyani, Illa Siva,Fatima, Anam
supporting information, p. 226 - 232 (2018/03/09)
Background: Pyrrole moiety is found in naturally occurring compounds such as chlorophyll, haem, and vitamin B12 and present in a number of drugs for example atorvastatin, ketorolac, elopiprazole, tolmetin and sunitinib. Various methods have been used for the synthesis of pyrrole derivatives; however, still there is a need for environmentally benign and economic protocol. Method: We have reported a simple, mild and speedy synthesis of N-substituted 2,5-dimethyl pyrrole derivatives in ‘’GAAS’’ as medium and catalyst at room temperature and under ultrasound irradiation. Results: This protocol was employed for the synthesis of various 2,5-dimethyl-N-substituted pyrrole-derivatives using both aliphatic as well as aromatic amines in short time (2 to 10 minutes)with excellent yield (84-95%) at room temperature and under ultrasonic irradiation. The catalytic system “GAAS’’ was regenerated and reused five times effectively without major loss of activity. Conclusion: In conclusion, we have developed an eco-friendly, simple, faster, reusable, mild, and efficient protocol for the synthesis of N-substituted pyrrole derivatives. This bio-based protocol is cost-effective and greener methodology for the synthesis of biologically active N-substituted pyrrole derivatives.
