- 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
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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.
- Behbahani, Farahnaz K.,Shokri, Fatemeh
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- Method for preparing N-aryl pyrrole compound
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The present invention relates to a method for preparing an N-aryl pyrrole compound. Furan containing different substituents, aromatic amine containing different substituents and a solid Lewis acid catalyst are mixed and placed in a closed reactor, and an N-aryl pyrrole compound with different substituents is prepared under certain catalytic conditions. The reaction temperature of the catalytic reaction condition is 140-210 DEG C. The solid Lewis acid catalyst is prepared by a sol-gel method, Hf is used as a core metal element, and a mesoporous molecular sieve SBA-15 is used as a carrier. According to the method, the catalyst is simple to prepare, low in cost, high in reaction activity, good in water resistance and structural stability and high in catalytic reaction yield; meanwhile, the Lewis acid type catalyst does not generate acid protons, the corrosion of the catalyst to equipment at high temperature is avoided, the post-reaction treatment is convenient, and the catalyst is renewable and environment-friendly.
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Paragraph 0021-0043; 0044
(2020/09/09)
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- SnCl2 catalyzed direct synthesis of pyrroles under aqueous conditions
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Synthetic substituted pyrroles are related with interesting biological activities, yet they remain inadequately explored within drug discovery. Late years have seen a growing interest in synthetic approaches that can provide access to structurally novel pyrroles so that the biological usefulness of this compound class can be more fully investigated. Herein, an efficient and versatile practical protocol for the pyrroles using stannous(II) chloride dihydrate as catalyst is described under aqueous conditions at 55 oC in high yields. Also, this method is applicable for the preparation of diversity and oriented pyrrole derivatives.
- Tejeswararao,Srikanth
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p. 795 - 802
(2020/03/24)
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- Fe3O4@SiO2-PTMS-Guanidine-SA nanoparticles as an effective and reusable catalyst for the synthesis of N-substituted pyrroles
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Fe3O4@SiO2-PTMS-Guanidine-SA nanoparticles used as an effective catalyst for the synthesis of N-substituted pyrroles. Pyrroles were synthesized from the reaction between primary amine derivatives and 2,5-hexanedione with high to excellent yields under mild reaction conditions. After completion of the reaction, Fe3O4@SiO2-PTMS-Guanidine-SA magnetic nanoparticles could be recovered easily from the reaction mixture by an external magnet and reused. This catalyst was characterized by FT-IR spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, thermogravimetric analysis and vibrating-sample magnetometry techniques.
- Rostami, Hedieh,Shiri, Lotfi
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p. 1329 - 1335
(2020/01/28)
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- Synthesis of Pyrrole Derivatives Promoted by Fe(ClO4)3/SiO2 as an Environmentally Friendly Catalyst
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N-Substituted pyrroles have been prepared in high isolated yields (702-99%) by the reaction of hexane-2,5-dione with amines or diamines in the presence of Fe(ClO4)3/SiO2 at ambient temperature under solvent-free conditions. The experimental procedure involves simple operations, and the products are readily separated by short column chromatography. 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.
- Arabpourian,Behbahani
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p. 682 - 685
(2019/07/19)
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- A New Green and Efficient Br?nsted: Lewis Acidic DES for Pyrrole Synthesis
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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.]
- Shaibuna,Theresa, Letcy V.,Sreekumar
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p. 2359 - 2372
(2018/06/20)
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- Bio-based material as medium, mild and reusable catalyst for paal–knorr pyrrole synthesis with and without ultrasonic irradiation
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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.
- Sharma, Abha,Kalyani, Illa Siva,Fatima, Anam
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supporting information
p. 226 - 232
(2018/03/09)
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- Greener Paal-Knorr Pyrrole Synthesis by Mechanical Activation
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A straightforward and solventless synthesis of pyrroles was developed by using mechanochemical activation and a biosourced organic acid as the catalyst. Relative to traditional Paal-Knorr methodologies, various N-substituted pyrroles were obtained in very short reaction times. By reaction with unreactive diketones, desymmetrized aliphatic and aromatic compounds were also synthesized.
- Akelis, Liudvikas,Rousseau, Jolanta,Juskenas, Robertas,Dodonova, Jelena,Rousseau, Cyril,Menuel, Stphane,Prevost, Dominique,Tumkeviius, Sigitas,Monflier, Eric,Hapiot, Frdric
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- Synthesis, antimycobacterial screening and ligand-based molecular docking studies on novel pyrrole derivatives bearing pyrazoline, isoxazole and phenyl thiourea moieties
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We report here the synthesis, antibacterial and antitubercular evaluation of 61 novel pyrrolyl derivatives bearing pyrazoline, isoxazole and phenyl thiourea moieties. Molecular docking was carried out on enoyl ACP reductase from Mycobacterium tuberculsosi
- Joshi, Shrinivas D.,Dixit, Sheshagiri R.,Kirankumar,Aminabhavi, Tejraj M.,Raju,Narayan, Ramanuj,Lherbet, Christian,Yang, Kap Seung
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p. 133 - 152
(2015/11/18)
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- The Paal-Knorr reaction revisited. A catalyst and solvent-free synthesis of underivatized and N-substituted pyrroles
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A new, modified synthesis of pyrroles is described. The reaction of 2,5-hexandione with a variety of amines yielded the expected pyrrole analogues in excellent yields. The reactions were carried out under the ultimate green conditions excluding both catalyst and solvent applying simple stirring at room temperature. The variety of amines include aqueous ammonium hydroxide for the synthesis of pyrroles with a free NH group, and benzylamines, anilines and phenylene-diamines for the synthesis of several N-derivatized pyrroles. The reaction also occurs efficiently with a variety of 1,4-diketones, although the reaction rates and yields are lower for the diketones that do not possess terminal methyl group(s). This journal is
- Cho, Hyejin,Madden, Richard,Nisanci, Bilal,T?r?k, Bla
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p. 1088 - 1099
(2015/03/04)
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- Synthesis of two distinct pyrrole moiety-containing arenes from nitroanilines using Paal-Knorr followed by an indium-mediated reaction
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Synthesis of arenes substituted with two differently substituted-pyrrole moieties was investigated. A Paal-Knorr condensation reaction of nitroanilines with 1,4-diketone to nitrophenyl-1H-pyrroles followed by an indium-mediated reduction-triggered coupling reaction with another kind of 1,4-diketone resulted in two distinct pyrrole-containing arenes, variously substituted 1-((1H-pyrrol-1-yl)phenyl)-1H-pyrroles, in reasonable yield.
- Kim, Byeong Hyo,Bae, Seolhee,Go, Ahra,Lee, Hyunseung,Gong, Cheoloh,Lee, Byung Min
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p. 265 - 276
(2015/12/30)
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- Synthesis, structural and biochemical activity studies of symmetrical and unsymmetrical pyrroles and their mononuclear Cu(II), Ni(II) and Co(II) complexes
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Monomeric copper(II), nickel(II) and Co(II) complexes of 2-(2,5-dimethyl-1H-pyrrol-1-yl)aniline, (dmpyph) and 1,1'-(1,2-phenylene)-bis(2, 5-dimethyl-1H-pyrrole) (tmpyph) were prepared and characterized by elemental analyses, magnetic moments, 1
- Senses,Karabocek,Karabocek,Ekmekcioglu
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experimental part
p. 3797 - 3801
(2012/09/08)
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- An approach to the Paal-Knorr pyrroles synthesis catalyzed by Sc(OTf)3 under solvent-free conditions
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A facile synthesis of N-substituted pyrroles by the Paal-Knorr condensation has been accomplished using a simple procedure. Among different metal triflates screened, 1 mol % Sc(OTf)3 efficiently promoted the reaction to give excellent yield (89-98%) under mild reaction conditions. Additionally, Sc(OTf)3 could be recovered easily after the reactions and reused without evident loss in activity.
- Chen, Jiuxi,Wu, Huayue,Zheng, Zhiguo,Jin, Can,Zhang, Xingxian,Su, Weike
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p. 5383 - 5387
(2007/10/03)
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- Imidazoline derivatives as alpha-1A adrenoceptor ligands
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Compound of formula (I) or a pharmaceutically acceptable salt or solvate thereof are disclosed. Such compounds are useful in the treatment of Alpha-1A mediated diseases or conditions such as urinary incontinence.
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Page/Page column 36
(2010/02/11)
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- Condensation of 2,3-pyridinediamines with acetonylacetone
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The reaction of 2,3-pyridinediamine 1a and its 5-bromo analogue 1b, independently, with acetonylacetone leads to the formation of 1:1 condensation products irrespective of the molar ratios employed.'The condensation products have been assigned 2-amino 2a and 5-bromo-2-amino-3 (2',5'-dimethylpyrrolyl)pyridine 2b structures. Authentic chemical evidence is given in support of the claim for these structures ruling out the equally probable alternative structure 3 for these compounds. Attempted studies on the reactivity of the latter compounds towards electrophilic reagents such as acetic arthydride, benzoyl chloride, and arylsulphonyl chlorides have been described.
- Dubey,Kumar, R. Vinod
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p. 1036 - 1040
(2007/10/03)
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