- Insights for diastereoselectivity in synthesis of 2,3-dihydropyrroles by photochemical ring contraction of 1,4-dihydropyridines
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Strategies by introducing chiral auxiliaries into the photoreactive substrate 1,4-dihydropyridines, an interesting diastereoselectivity of 2,3-dihydropyrroles in the process of photochemical ring contraction was observed. The diastereoselectivity of (2R,3
- Wang, Shijie,Wang, Huiqin,Tian, Nana,Yan, Hong
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supporting information
(2021/01/25)
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- g-C3N4@Ce-MOF Z-scheme heterojunction photocatalyzed cascade aerobic oxidative functionalization of styrene
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A special composite of the cerium-based metal-organic framework (Ce-UiO-66) modified with graphitic carbon nitride nanosheets (g-C3N4) has been synthesized. In order to make a comparison, a series of composites comprising g-C3N4and Ce-MOF were synthesized as well. Their structural features were investigated using Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (PXRD), sorption of nitrogen (BET and BJH), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), X-ray fluorescence spectroscopy (XRF) and diffuse reflectance UV-Vis spectroscopy (UV-Vis DRS) and electron spin resonance (ESR) techniques. According to the obtained results, it was found that nanosheets of mesoporous g-C3N4act as linkers between the cerium sites, playing a critical role in the formation of composites. In fact, the embedded g-C3N4nanoparticles in the Ce-MOF cause a new kind of meso-porosity. Moreover, the coordination of nitrogen atoms in the graphitic carbon nitride structure to cerium atoms of the crystal brings about substantial changes in the optical properties, increasing the photoreactivity. On the other hand, since there is a physical contact between Ce-UiO-66 and g-C3N4in the composite, the unaltered pore volume and optical properties lead to the formation of a physical mixture rather than a composite. The g-C3N4@Ce-MOF as a photocatalyst was employed in photocatalytic aerobic oxidative Hantzsch pyridine synthesis of styrene and indicated high performance under visible light. The stability and reusability of g-C3N4@Ce-MOF were also examined and showed high efficiency up to the 5th run. Besides, the PXRD and FT-IR analyses taken from the retrieved g-C3N4@Ce-MOF nanocomposite confirmed the catalyst stability after the completion of the cascade aerobic oxidative reaction. Despite the photocatalytic performance, the synergistic effect of open metal sites in the MOF as Lewis acid and nitrogen in g-C3N4have greatly improved the efficiency of the catalyst. Moreover, the study of the reaction mechanism using ESR indicates the positive effect of composite formation on the performance of the photocatalytic aerobic oxidation reaction by the superoxide radical (O2˙—), as a selective oxidant species.
- Karimia, Meghdad,Sadeghia, Samira,Gavinehroudi, Reza Ghahremani,Mohebali, Haleh,Mahjoub, Alireza,Heydari, Akbar
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p. 6671 - 6681
(2021/04/22)
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- Ferric Sulfasalazine Sulfa Drug Complex Supported on Cobalt Ferrite Cellulose; Evaluation of Its Activity in MCRs
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Abstract: The green and nano catalyst was simply prepared through the reaction of ferric sulfasalazine with nanomaterial CoFe2O4-cellulose as a magnetic biopolymer surface. This novel heterogeneous organometallic catalyst was charact
- Rostamizadeh, Shahnaz,Daneshfar, Zahra,Khazaei, Ali
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p. 2091 - 2114
(2020/01/31)
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- [Fesipmim]Cl as highly efficient and reusable catalyst for solventless synthesis of dihydropyridine derivatives through Hantzsch reaction
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Abstract: In the present investigation, magnetic ferrite nanoparticles (ferrite NPs) were synthesized and coated with silica (ferrite?SiO2NPs) by using the sol-gel method. After that, silica propylmethylimidazolium chloride ionic liquid [Sipmim]Cl was prepared and linked with the above-prepared ferrite?SiO2NPs to synthesize ferrite silica propylmethylimidazolium chloride [Fesipmim]Cl catalyst. The formation of [Fesipmim]Cl catalyst was confirmed by Fourier-transform infrared (FT-IR) spectroscopy analysis. X-ray diffraction (XRD) analysis confirmed the structure of ferrite NPs and ferrite?SiO2 NPs. Transmission electron microscopy (TEM) evidenced the successful formation of ferrite NPs and ferrite?SiO2 NPs. Scanning electron microscopy (SEM) results revealed the change in morphology of ferrite NPs, ferrite?SiO2NPs and [Fesipmim]Cl. The magnetic properties of [Fesipmim]Cl catalyst were measured by vibrating sample magnetometer (VSM). The efficiency of the [Fesipmim]Cl catalyst was checked by using it for the synthesis of different derivatives of dihydropyridine through Hantzsch reaction via a three-component coupling reaction of substituted benzaldehydes, ethyl/ methyl acetoacetate and ammonium acetate. The formation and structures of all the synthesized compounds were confirmed by FT-IR, 1HNMR, 13C NMR spectral analyses. The reusability of the catalyst [Fesipmim]Cl was checked up to seven cycles and found to have excellent activity up to five cycles. Graphic abstract: [Figure not available: see fulltext.].
- Agrwal, Akansha,Kasana, Virendra
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- Metal free biomimetic deaminative direct C-C coupling of unprotected primary amines with active methylene compounds
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An unprecedented direct C-C coupling reaction of unprotected primary amines with active methylene compounds is reported. The reaction involves a biomimetic deamination of amines which was achieved under conditions free of metallic reagents and strong oxidizing agents. A wide range of primary amines was reacted with different active methylene compounds to provide structurally diverse trisubstituted alkenes and dihydropyridines. A kinetic study revealed an activation barrier of 10.1 kcal mol-1 for the conversion of a key intermediate of the reaction.
- Ghosh, Santanu,Jana, Chandan K.
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supporting information
p. 10153 - 10157
(2019/12/26)
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- MIL-101-SO3H metal-organic framework as a Br?nsted acid catalyst in Hantzsch reaction: An efficient and sustainable methodology for one-pot synthesis of 1,4-dihydropyridine
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A straightforward and efficient methodology for the one-pot multicomponent synthesis of 1,4-dihydropyridine has been developed using MIL-101-SO3H metal-organic framework as a solid Br?nsted acid. The presence of the uniformly distributed Br?nsted acidic sulfonic acid sites throughout the framework and the high stability bestow the catalyst with excellent reactivity towards the synthesis of 1,4-dihydropyridine under simple reaction conditions using renewable ethanol as the solvent. The present methodology tolerates various functional groups and allows the synthesis of 1,4-dihydropyridine derivatives in good to excellent yields through Hantzsch reaction. The developed methodology proceeds under mild conditions, avoids corrosive reagents and special reaction conditions, and is amenable to gram scale synthesis. The sustainable nature of the catalyst was proved by the easy recovery and the reusability of the catalyst, as it was reused several times without loss in activity, which was confirmed from the FTIR, PXRD and SEM analyses of the reused catalyst.
- Devarajan, Nainamalai,Suresh, Palaniswamy
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p. 6806 - 6814
(2019/05/10)
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- Preparation method and application of novel ionic beta-naphthol aldehyde Schiff base zirconium complex
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The invention belongs to the technical field of catalytic organic synthesis, and particularly relates to a preparation method and application of a novel ionic beta-naphthol aldehyde Schiff base zirconium complex. Zirconium atoms are coordinated with a beta-naphthol aldehyde Schiff base ligand and water molecules, and two perfluoroalkyl (aryl) sulfonic acid groups are combined with central atom zirconium through covalent bonds and ionic bonds respectively. The preparation method comprises the following steps: dissolving beta-naphthol aldehyde Schiff base zirconium dichloride in a solvent, adding a silver salt under the protection of N2, reacting the mixture for 1-4 hours in a dark place at room temperature, performing filtration, adding n-hexane into filtrate until layering, putting the solution into a refrigerator, and freezing the solution for 24 hours to separate out the beta-naphthol aldehyde Schiff base zirconium complex. The beta-naphthol aldehyde Schiff base zirconium complex hashigh air stability and strong Lewis acidity, and can efficiently catalyze the Hantzsch reaction of aldehyde, beta-ketoester and ammonium acetate to synthesize 1,4-dihydropyridine derivatives.
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-
Paragraph 0041; 0064-0065
(2019/12/02)
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- Synergistic catalytic effect between ultrasound waves and pyrimidine-2,4-diamine-functionalized magnetic nanoparticles: Applied for synthesis of 1,4-dihydropyridine pharmaceutical derivatives
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A convenient strategy for synthesis of the various derivatives of 1,4-dihydropyridine (1,4-DHP), as one of the most important pharmaceutical compounds, is presented in this study. For this purpose, firstly, magnetic iron oxide nanoparticles (Fe3O4 NPs) were fabricated and suitably coated by silica network (SiO2) and trimethoxy vinylsilane (TMVS). Then, their surfaces were well functionalized with pyrimidine-2,4-diamine (PDA) as the main active sites for catalyzing the synthesis reactions. In this regard, the performance of three different methods including reflux, microwave (MW) and ultrasound wave (USW) irradiations have been comparatively monitored via studying various analyses on the fabricated nanocatalyst (Fe3O4/SiO2-PDA). Concisely, high efficiency of the USW irradiation (in an ultrasound cleaning bath with a frequency of 50 kHz and power of 250 W/L) has been well proven through the investigation of the main factors such as excellent surface-functionalization, core/shell structure conservation, particle uniformity, close size distribution of the particles, and great inhibition of the particle aggregation. Then, the effectiveness of the USW irradiation as a promising co-catalyst agent has been clearly demonstrated in the 1,4-DHP synthesis reactions. It has been concluded that the USW could provide more appropriate conditions for activation of the catalytic sites of Fe3O4/SiO2-PDA NPs. However, high reaction yields (89%) have been obtained in the short reaction times (10 min) due to the substantial synergistic effect between the presented nanocatalyst and USW.
- Taheri-Ledari, Reza,Rahimi, Jamal,Maleki, Ali
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- 1,4-Dihydropyridine/BF3OEt2 for the reduction of imines: Influences of the amount of added BF3OEt2 and the substitution at N-1 and C-4 of the dihydropyridine ring
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We have evaluated four 1,4-dihydropyridines (DHPs 1a, 1b, 1c and 1d) as reducing agents, which presented free (hydrogenated) or phenyl-substituted N-1 and C-4 positions of the DHP ring. Reactions combining each of the DHP and different amounts of BF3OEt2 were evaluated for the reduction of imine 2a (N-benzylideneaniline). DHP simultaneously substituted at N-1 and C-4 (1a), and DHP substituted at C-4 (1b) gave lower yields for reduction of 2a in comparison with DHPs 1c and 1d (both unsubstituted at the C-4 position). By evaluating the amount of added BF3OEt2 to the reaction mixture, we have found that DHP 1c (substituted at N-1) provided its best yield for amine 3a (82%) when associated with stoichiometric amounts BF3OEt2, while DHP 1d (N-1- and C-4-unsubstituted derivative) was more effective (90% yield) with catalytic quantities of the Lewis acid. The reaction system using DHP 1c under stoichiometric BF3OEt2 could also be successfully applied with additional imine examples and under reductive amination conditions.
- Zattoni, Ingrid F.,Guanaes, Lais D.,Cerqueira, Letícia B.,Pontarolo, Roberto,Ducatti, Diogo R.B.,Duarte, M. Eugênia R.,Noseda, Miguel D.,Trindade, Angela C.L.B.,Gon?alves, Alan G.
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supporting information
(2019/09/12)
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- The efficient synthesis of Hantzsch 1,4-dihydropyridines via metal-free oxidative C–C coupling by HBr and DMSO
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A novel and efficient synthesis of Hantzsch 1,4-dihydropyridines through metal-free oxidative C–C coupling process was described. The reaction between benzylic alcohols, 1,3-dicarbonyl compounds and ammonium hydroxide in the presence of HBr in DMSO at 75 °C led to afford 1,4-dihydropyridine in excellent yields. This protocol introduces the use of benzyl alcohols instead of aldehydes as a new modification of the Hantzsch reaction.
- Rezaei, Narjes,Ranjbar, Parviz Rashidi
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p. 4102 - 4106
(2018/10/20)
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- Hantzsch Reaction Starting Directly from Alcohols through a Tandem Oxidation Process
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A Br?nsted acidic ionic liquid, 3-(N,N-dimethyldodecylammonium) propanesulfonic acid hydrogen sulphate ([DDPA][HSO4]), has been successfully applied to catalyze sequential oxidation of aromatic alcohols with NaNO3 followed by their c
- Liu, Xiaobing,Liu, Bin
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- Method for synthesizing 1,4-dihydropyridines derivatives
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The invention relates to a method for synthesizing 1,4-dihydropyridines derivatives. According to the method, a fluorescence-marked nonmetal organic boron-nitrogen lewis acid-alkali dual-functional complex is used as a catalyst, so that the pollution of heavy metals is effectively avoided; the catalyst can be recycled, and a residual amount of the catalyst in a product can be rapidly detected; and the source of raw materials is wide, the target yield is close to 100 percent, the reaction process is a homogenous reaction, and a product is obtained by virtue of chromatographic separation. The whole reaction system can be directly amplified, and the industrialization prospect is significant.
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Paragraph 0022; 0023; 0024; 0025; 0026; 0027; 0028-0111
(2017/10/27)
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- A New Type of Magnetically-Recoverable Heteropolyacid Nanocatalyst Supported on Zirconia-Encapsulated Fe3O4 Nanoparticles as a Stable and Strong Solid Acid for Multicomponent Reactions
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Abstract: A novel highly efficient magnetically retrievable catalyst was developed by the immobilization of H3PW12O40 (20–60 wt%) on the surface of zirconia-encapsulated Fe3O4 nanoparticles. The prepared HPW supported on nano-Fe3O4@ZrO2 heterogeneous acid catalyst (or n-Fe3O4@ZrO2/HPW) was fully characterized by several physicochemical techniques such as: Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, vibrating sample magnetometry and thermogravimetric analysis. The FT-IR spectroscopic data revealed that H3PW12O40 molecules on the nano-Fe3O4@ZrO2 support existed in the Keggin structure. The acidity of the catalyst was measured by the help of a potentiometric titration with n-butylamine. It was surprising that this very strong solid acid catalyst exhibited an excellent acid strength which was as a result of possessing a higher number of surface active sites compared to its homogeneous analogues. The catalytic activity of the as-prepared novel nano-Fe3O4@ZrO2/HPW was explored through the one-pot three-component synthesis of different 3,4-dihydropyrimidin-2(1H)-ones (i.e. Biginelli reaction) and 1,4-dihydropyridines (i.e. Hantzsh reaction) under solvent free condition. The sample of 40 wt% showed higher acidity and activity in the catalytic transformation. After the reaction, the catalyst/product isolation could be easily achieved with an external magnetic field and the catalyst could be easily recycled for at least five times without any decrease in its high catalytic activity. The excellent recyclability was attributed to the strong interaction between the hydroxyl groups of the nano-Fe3O4@ZrO2 support and the HPW species. Graphical Abstract: [Figure not available: see fulltext.].
- Zolfagharinia, Somayeh,Kolvari, Eskandar,Koukabi, Nadiya
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p. 1551 - 1566
(2017/05/17)
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- An efficient and recyclable 3D printed α-Al2O3 catalyst for the multicomponent assembly of bioactive heterocycles
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A catalytic methodology is reported that enables the efficient, operationally simple and environmentally friendly synthesis of diverse 1,4-dihydropyridines and 3,4-dihydropyrimidin-2(1H)-ones, including some relevant drugs and pharmacologically active derivatives. This strategy is based on the use of a 3D printed Al2O3 woodpile material that was sintered to generate a rigid structure with controlled porosity and noteworthy catalytic performance. The 3D printed Al2O3 catalyst exhibits remarkable efficacy as a Lewis acid in Biginelli and Hantzsch reactions and it can be recovered and reused ten times without any decrease in the activity. Remarkable E factors, excellent recyclability and scalability, broad substrate scope, short reaction times, excellent yields, solvent-free conditions and easy isolation procedures are key features of this methodology.
- Azuaje, Jhonny,Tubío, Carmen R.,Escalante, Luz,Gómez, Mónica,Guitián, Francisco,Coelho, Alberto,Caama?o, Olga,Gil, Alvaro,Sotelo, Eddy
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p. 203 - 210
(2016/12/09)
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- Computational investigations on structural and electronic properties of CuI nanoparticles immobilized on modified poly(styrene-co-maleic anhydride), leading to an unexpected but efficient catalyzed synthesis of 1,4-dihydropyridine via Hantzsch pyridine synthesis
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A, quantitative description for the interaction of Cu(I) with poly(styrene-co-maleic anhydride) modified with 4-aminopyridine (denoted as CuI/SMI complex) is presented using density functional theory (DFT) and quantum theory of atoms in molecules (QTAIM) approaches. Topological analysis of electron density revealed the existence of effective interactions between Cu(I) ions and the nitrogen in the pyridine ring. Interestingly, the results also showed that there is considerable interaction between Cu(I) and the oxygen of the carbonyl motif in the SMI ligand. Thus, CuI/SMI was examined as a heterogeneous and recyclable catalyst in Hantzsch pyridine synthesis under solvent-free conditions, affording diverse 1,4-dihydropyridines (1,4-DHPs) in excellent yields with relatively short reaction times.
- Heravi, Majid M.,Hosseinnejad, Tayebeh,Nazari, Niousha
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p. 530 - 536
(2017/05/31)
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- Synthesis of 2,3-dihydropyrroles by photo rearrangement of Hantzsch 1,4-dihydropyridines with high diastereoselectivity
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The Hantzsch 1,4-dihydropyridines were found to be transforming to the 2,3-dihydropyrroles by photo rearrangement with air under irradiation of LED light (410?nm) with high diastereoselectivity (dr?>?20:1). This reaction includes tandem photo oxidation/rearrangement. The 2,3-dihydropyrroles were obtained in moderate yields with successfully one-pot process starting from aldehydes, ammonium acetate and ethyl acetoacetate.
- Zhong, Qidi,Fan, Qiangwen,Yan, Hong
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supporting information
p. 1292 - 1295
(2017/03/10)
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- Intermolecular [2 + 2] Cycloaddition of 1,4-Dihydropyridines with Olefins via Energy Transfer
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A highly regio- and diastereoselective visible-light-promoted [2 + 2] cycloaddition between readily available 1,4-dihydropyridines and olefins has been developed. This strategy is operationally simple and atom-economical and enables the construction of strained polysubstituted 2-azabicyclo[4.2.0]octanes with three all-carbon quaternary centers with good functional group tolerance. These products can be easily converted to various structurally unique derivatives. The primary mechanistic studies demonstrated that the reaction proceeds through an energy transfer pathway.
- Wang, Chengfeng,Lu, Zhan
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supporting information
p. 5888 - 5891
(2017/11/10)
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- Vanadium(IV and v) complexes of pyrazolone based ligands: Synthesis, structural characterization and catalytic applications
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The ONO donor ligands obtained from the condensation of 4-benzoyl-3-methyl-1-phenyl-2-pyrazoline-5-one (Hbp) with benzoylhydrazide (H2bp-bhz I), furoylhydrazide (H2bp-fah II), nicotinoylhydrazide (H2bp-nah III) and isonicotinoylhydrazide (H2bp-inh IV), upon treatment with [VIVO(acac)2], lead to the formation of [VIVO(bp-bhz)(H2O)] 1, [VIVO(bp-fah)(H2O)] 2, [VIVO(bp-nah)(H2O)] 3 and [VIVO(bp-inh)(H2O)] 4, respectively. At neutral pH the in situ generated aqueous K[H2VVO4] reacts with ligands I and II, forming potassium salts, K(H2O)2[VVO2(bp-bhz)] 5 and K(H2O)2[VVO2(bp-fah)] 6, while ligands III and IV give neutral complexes, [VVO2(Hbp-nah)] 9 and [VVO2(Hbp-inh)] 10, respectively. Acidification of aqueous solutions of 5 and 6 with HCl also gives neutral complexes [VVO2(Hbp-bhz)] 7 and [VVO2(Hbp-fah)] 8, respectively. Complexes 1-4, upon slow aerial oxidation in methanol, convert into monooxidovanadium(v) complexes, [VVO(bp-bhz)(OMe)] 11, [VVO(bp-fah)(OMe)] 12, [VVO(bp-nah)(OMe)] 13 and [VVO(bp-inh)(OMe)] 14, respectively. All complexes were characterized by various spectroscopic techniques like FT-IR, UV-visible, EPR (for complexes 1-4) and NMR (1H, 13C and 51V), elemental analysis, thermogravimetry and single crystal X-ray diffraction (for complexes 5-10 and 12). In the solid state, all complexes characterized by X-ray diffraction show the metal ion 5-coordinated in a distorted square pyramidal geometry. Complexes 11-14 were tested as catalysts for the one-pot three-component (ethylacetoacetate, benzaldehyde and ammonium acetate) dynamic covalent assembly, via Hantzsch reaction, using hydrogen peroxide as oxidant in solution and under solvent-free conditions. The complexes are also active catalysts for the oxidation of tetralin to tetralone with H2O2 as oxidant. The influence of the amounts of catalyst and oxidant, and solvent, temperature and time on the catalyzed reactions was investigated.
- Maurya, Mannar R.,Sarkar, Bithika,Avecilla, Fernando,Correia, Isabel
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p. 17343 - 17364
(2016/11/13)
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- Study of temperature dependent three component dynamic covalent assembly VIa Hantzsch reaction catalyzed by dioxido- and oxidoperoxidomolybdenum(VI) complexes under solvent free conditions
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Tridentate ONO donor ligands derived from heterocyclic compound 4-acetyl-3-methyl-1-phenyl-2-pyrazoline-5-one (Hap) and aromatic hydrazides {benzoyl hydrazide (Hbhz), isonicotinoyl hydrazide (Hinh), nicotinoyl hydrazide (Hnah) and furoyl hydrazide (Hfah)} react with [MoVIO2(acac)2] (Hacac = acetylacetone) in equimolar ratio in methanol to give dioxidomolybdenum(vi) complexes, [MoO2(ap-bhz)(MeOH)] 1, [MoO2(ap-inh)(MeOH)] 2, [MoO2(ap-nah)(MeOH)] 3 and [MoO2(ap-fah)(MeOH)] 4. Reaction of these ligands with in situ generated oxidoperoxidomolybdenum(vi) precursor results in the formation of oxidoperoxidomolybdenum(vi) complexes, [MoO(O2)(ap-bhz)(MeOH)] 5, MoO(O2)(ap-inh)(MeOH)] 6, MoO(O2)(ap-nah)(MeOH)] 7 and MoO(O2)(ap-fah)(MeOH)] 8. These complexes have been characterized by elemental analysis, spectroscopic techniques (infrared, UV-vis, 1H and 13C NMR) and thermogravemetric analysis. The structures of complexes [MoVIO2(ap-bhz)(H2O)] 1a (water coordinated), [MoVIO2(ap-bhz)(DMSO)] 1b (DMSO coordinated), [MoVIO2(ap-nah)(DMF)] 3a (DMF coordinated), [MoVIO(O2)(ap-bhz)(MeOH)] 5 (methanol coordinated) and [MoVIO(O2)(Hap-nah)(OMe)]·MeOH 7a (methoxy coordinated) have been confirmed by single crystal X-ray studies. X-ray diffraction study also reveals that tridentate ligands bind to the metal center through enolic oxygen (of pyrazolol), azomethine nitrogen and enolic oxygen (of hydrazide) atoms. In complex 7a, pyridinic nitrogen is protonated. These complexes [dioxidomolybdenum(vi) as well as oxidoperoxidomolybdenum(vi)] have been tested as catalysts for temperature dependent one pot three component (methylacetoacetate, benzaldehyde and ammonium acetate) dynamic covalent assembly, via Hantzsch reaction, using 30% H2O2 as a green oxidant under solvent free conditions. Various parameters such as the amount of catalyst, oxidant and temperature of the reaction mixture have been taken into consideration to optimize the reaction conditions. In the Hantzsch reaction, the temperature and oxidant control the conversion and selectivity of the desired product.
- Maurya, Mannar R.,Saini, Neeraj,Avecilla, Fernando
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p. 12993 - 13009
(2016/02/12)
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- Novel Magnetically Separable Sulfated Boric Acid Functionalized Nanoparticles for Hantzsch Ester Synthesis
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A novel, separable, solid-acid catalyst consisting of sulfated boric acid nanoparticles immobilized on a silica-coated magnetite support was prepared. This catalyst permits the preparation of dihydropyridine derivatives (Hantzsch esters) by condensation of an aldehyde with two equivalents of a β-keto ester in the presence of ammonium acetate. The catalyst can be recovered and recycled.
- Azizi, Kobra,Azarnia, Jamshid,Karimi, Meghdad,Yazdani, Elahe,Heydari, Akbar
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supporting information
p. 1810 - 1813
(2016/07/16)
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- Heterogeneous bimetallic ZnFe2O4nanopowder catalyzed synthesis of Hantzsch 1,4-dihydropyridines in water
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The mixed metal oxide ZnFe2O4nanopowder, a dual Lewis acid–base combined catalyst is found to efficiently catalyze a multicomponent synthesis of 1,4-dihydropyridines from aldehydes, ethyl acetoacetate, and ammonium acetate in water. This procedure offers several advantages including high yields, short reaction times, a simple work-up procedure, and a benign eco-footprint. This method takes advantage of the fact that water, a green solvent is used in combination with ZnFe2O4nanoparticles as catalyst which can be easily recovered magnetically and reused for further runs.
- Ravikumar Naik,Shivashankar
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supporting information
p. 4046 - 4049
(2016/08/18)
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- A Simple and Efficient One-pot Synthesis of 1,4-dihydropyridines Using Nano-WO3-supported Sulfonic Acid as an Heterogeneous Catalyst under Solvent-free Conditions
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Nano-tungsten trioxide-supported sulfonic acid (n-WSA) was found to be an effective heterogeneous catalyst for the one-pot reaction of aromatic aldehydes, β-dicarbonyl compounds and ammonium acetate to afford 1,4-dihydropyridine derivatives in good to excellent yields. The other main advantages of the present method are short reaction times, simple workup, ease in purification and environmentally benign methodology. The reaction conditions were optimized employing Response Surface Method technique (Central Composite Design (CCD)) which is economically considerable because of the minimum number of experiments required to evaluate the effects of multiple parameters on the response.
- Bitaraf, Mehrnoosh,Amoozadeh, Ali,Otokesh, Somayeh
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p. 336 - 344
(2016/05/09)
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- Synthesis of hantzsch 1,4-dihydropyridines in a continuous flow microreactor
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A simple and efficient synthesis of Hantzsch 1,4-dihydropyridines from the condensation of benzaldehydes with alkyl acetoacetates/benzoylacetate and aqueous ammonia in the absence of catalyst has been developed by using a continuous flow microreactor. Under optimized condition, various 1,4-dihydropyridines were obtained in 80-93% yield with high atom efficiency. Compared with using batch system, the present smooth procedure greatly accelerated the reaction due to the excellent mixing and mass transfer of reactant in micro flow system.
- Gao, Peiyuan,Sun, Xuan,Lei, Ming,Zhang, Hong
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p. 755 - 761
(2017/04/10)
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- Benzyltrimethylammoniumfluoride Hydrate: An Efficient Catalyst for One-Pot Synthesis of Hantzsch 1,4-Dihydropyridines and Their Aromatization
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An efficient, cost-effective and simple protocol has been developed for the synthesis of Hantzsch 1,4-dihydropyridines and their oxidation into pyridines using benzyltrimethylammonium fluoride hydrate as an excellent catalyst under solvent-free condition. All of the products synthesized by this method are characterized by various spectroscopic methods (IR, 1H NMR, 13C NMR, and DEPT).
- Khaskel, Anamika,Barman, Pranjit
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p. 114 - 120
(2016/04/01)
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- Functionalized calix[4]arene-based receptor for saccharide recognition
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A novel class of functionalized-calix[4]arene such as 1,4-dihydropyridine-calix[4]arene, acridine-calix[4]arene and pyrimidine-calix[4]arene were synthesized using multicomponent reaction. These compounds have been characterized by 1H NMR, 13C NMR and HRMS. Fluorescent and 1H NMR titration investigations reveal that these derivatives have the high binding constant towards the monosaccharide and disaccharide in aqueous solution. The formation of complex was also supported by electrospray mass spectrometry.
- Mirza-Aghayan, Maryam,Yarmohammadi, Masoud,Mohammadian, Narges,Zadmard, Reza,Asadi, Fatemeh
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- A study of the temperature effect on Hantzsch reaction selectivity using Mn and Ce oxides under solvent-free conditions
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In this communication, four materials (CeO2, CeO2(Cu), MnOx, and MnOx(Cu))were prepared, characterized and tested as catalysts, in solvent-free conditions, for the multicomponent Hantzsch reactions to obtain alternatively the 1,4-dihydropyridine or 2-phenylpyridine depending on the reaction conditions. 1,4-Dihydropyridine 4 was the main product formed at 80°C (76%), and 2-phenylpyridine 7 was the main product at 40°C (91%), in oxidant-free conditions, using CeO2 catalyst. It is the first report that shows that, not only the temperature but also the nature of the catalyst may change the product selectivity in Hantzsch reactions.
- D'Alessandro, Oriana,Sathicq, ángel G.,Sambeth, Jorge E.,Thomas, Horacio J.,Romanelli, Gustavo P.
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supporting information
p. 65 - 69
(2015/02/19)
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- Air-stable zirconocene bis(perfluorobutanesulfonate) as a highly efficient catalyst for synthesis of N-heterocyclic compounds
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Zirconocene bis(perfluorobutanesulfonate) is air- and water-stable and proved to be ionic on basis of conductivity measurements. It exhibits high catalytic efficiency for the synthesis of N-heterocyclic compounds under solvent-free condition, such as benzimidazoles, benzodiazepines, dihydropyrimidinones and dihydropyridines under mild condition. Furthermore, it can be reused without loss of activity in a test of five cycles. This catalytic system affords a simple and efficient approach for the synthesis of N-heterocyclic compounds.
- Wang, Jinying,Li, Ningbo,Qiu, Renhua,Zhang, Xiaohong,Xu, Xinhua,Yin, Shuang-Feng
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- Ultrasound-mediated, uranyl nitrate hexahydrate-catalyzed synthesis of 1,4-dihydropyridines under mild conditions
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Abstract Synthesis of 1,4-dihydropyridines by three-component condensation reaction of aldehyde, 1,3-dicarbonyl compounds, and ammonium acetate have been found to be efficiently catalyzed by uranyl nitrate hexahydrate [UO2(NO3)2 ·6H2O] at room temperature under ultrasound irradiation. This novel synthetic method offers the advantages of high yields, short reaction times, simplicity, and easy workup compared to the conventional methods reported in the literature.
- Palakshi Reddy,Sarveswari,Vijayakumar
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p. 6877 - 6883
(2015/08/18)
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- Synthesis of pyridinium salts from N-substituted dihydropyridines with BF3OEt2 in the absence of added oxidants
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Abstract N-Substituted dihydropyridines were converted into pyridinium salts with BF3OEt2 as aromatization promoter in reactions that could be conducted without the need of the usually added oxidizing agents, such as quinones, nitrat
- Guanaes, Lais D.,Ducatti, Diogo R.B.,Duarte, M. Eugênia R.,Barreira, Sandra M.W.,Noseda, Miguel D.,Gon?alves, Alan G.
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supporting information
p. 2001 - 2004
(2015/03/30)
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- Covalently Bonded Ionic Liquid-Type Sulfamic Acid onto SBA-15: SBA-15/NHSO3H as a Highly Active, Reusable, and Selective Green Catalyst for Solvent-Free Synthesis of Polyhydroquinolines and Dihydropyridines
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Amine-functionalized ordered mesoporous organic-inorganic hybrid materials are designed as solid supports to covalently immobilize the SO3H group to achieve sulfamic acid (SBA-15/ NHSO3H) as a novel catalyst. SBA-15/NHSO3H
- Rostamnia, Sadegh,Hassankhani, Asadollah
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p. 2753 - 2756
(2015/05/04)
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- Improving the selectivity toward three-component biginelli versus hantzsch reactions by controlling the catalyst hydrophobic/hydrophilic surface balance
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The catalytic activities and selectivities of two kinds of mesoporous solid acids SBA-15-PrSO3H 1, SBA-15-Ph-PrSO3H 2, and a periodic mesoporous organosilica (PMO) based solid acid Et-PMO-Me-PrSO3H 3 that comprise differen
- Karimi, Babak,Mobaraki, Akbar,Mirzaei, Hamid M.,Zareyee, Daryoush,Vali, Hojatollah
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p. 212 - 219
(2014/01/23)
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- Alginic acid: A highly efficient renewable and heterogeneous biopolymeric catalyst for one-pot synthesis of the Hantzsch 1,4-dihydropyridines
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Alginic acid, a naturally occurring polysaccharide, in its granular form and without any post-modification was found to be an efficient, environmentally benign, easily recoverable and low-cost catalyst for the clean and rapid synthesis of 1,4-dihydropiridine derivatives (DHPs) just based on its polysaccharide architecture. The Hantzsch pseudo-four-component reaction of ethyl or methyl acetoacetate, ammonium acetate and different aldehydes is catalyzed by alginic acid efficiently under mild conditions to afford the desired products in high to quantitative yields and clean reaction profiles. Avoiding the use of any transition metal, the use of a one-pot and multi-component procedure for the synthesis of DHPs, the reusability of the catalyst and operational simplicity are important features of this methodology.
- Dekamin, Mohammad G.,Ilkhanizadeh, Siamand,Latifidoost, Zahra,Daemi, Hamed,Karimi, Zahra,Barikani, Mehdi
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p. 56658 - 56664
(2015/02/02)
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- Covalently bonded ionic liquid-type sulfamic acid onto SBA-15: SBA-15/NHSO3H as a highly active, reusable, and selective green catalyst for solvent-free synthesis of polyhydroquinolines and dihydropyridines
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Amine-functionalized ordered mesoporous organic-inorganic hybrid materials are designed as solid supports to covalently immobilize the SO3H group to achieve sulfamic acid (SBA-15/ NHSO3H) as a novel catalyst. SBA-15/NHSO3H
- Rostamnia, Sadegh,Hassankhani, Asadollah
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p. 2753 - 2756
(2015/01/08)
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- Magnetic Fe3O4 nanoparticles: Efficient and recoverable nanocatalyst for the synthesis of polyhydroquinolines and Hantzsch 1,4-dihydropyridines under solvent-free conditions
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A green approach for efficient and rapid synthesis of biologically active substituted Hantzsch 1,4-dihydropyridine and polyhydroquinoline derivatives using magnetic Fe3O4 nanoparticles (Fe3O 4 MNPs) as a recyclable catalyst under solvent-free conditions was reported. The catalyst was characterized by FT-IR, XRD, and TEM analysis. Compared to the classical reactions, this method consistently has the advantages of short reaction times, little catalyst loading, high yields, easy magnetic separation and reusability of the catalyst.
- Nasr-Esfahani, Masoud,Hoseini, S. Jafar,Montazerozohori, Morteza,Mehrabi, Rasool,Nasrabadi, Hasan
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- Basic isoreticular nanoporous metal-organic framework for Biginelli and Hantzsch coupling: IRMOF-3 as a green and recoverable heterogeneous catalyst in solvent-free conditions
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The IRMOF-3 metal-organic framework (MOF) acts as a suitable green catalyst for the one-pot synthesis of dihydropyrimidinone and dihydropyridine derivatives through the Biginelli and Hantzsch reactions, and the desired products were obtained in high yield
- Rostamnia, Sadegh,Morsali, Ali
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p. 10514 - 10518
(2014/03/21)
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- Synthesis, anticonvulsant activity and molecular properties prediction of dialkyl 1-(di(ethoxycarbonyl)methyl)-2,6-dimethyl-4-substituted-1,4- dihydropyridine-3,5-dicarboxylates
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The synthesis and anticonvulsant properties of new N-diethylmalonyl derivatives of nifedipine and other isosteric analogues (7a-7n) were described. Anticonvulsant screening was performed by subcutaneous pentylenetetrazole (scPTZ) and maximal electroshock (MES) induced seizures tests. Majority of the compounds were effective in scPTZ and MES screens. Compound 7k showed good activity displaying maximum protection, which may be due to the presence of styryl moiety at position 4 of 1,4-dihydropyridine nucleus and the methyl groups of diester functionality. Compounds 7a-7d, 7g, 7i and 7k obeyed the Lipinski's "rule of five" and have drug-likeness. Based on computational prediction of molecular and pharmacokinetic properties, it was found that the compounds have good oral absorption.
- Prasanthi,Prasad,Bharathi
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- (NH4)2.5H0.5PW12O 40-catalyzed rapid and efficient one-pot synthesis of dihydropyridines via the Hantzsch reaction under solvent-free conditions
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A heterogeneous reaction with the ammonium salt of 12-tungstophosphoric acid as catalyst has been designed for synthesis of 1,4-dihydropyridine and polyhydroquinoline via the Hantzsch condensation. Molten tetrabutylammonium bromide ionic liquid was used a
- Ghattali, Seyyed Naeim,Saidi, Kazem,Khabazzadeh, Hojatollah
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p. 281 - 291
(2014/02/14)
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- Synthesis and photoluminescent properties of novel 1,4-dihydropyridine derivatives
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Six new 1,4-dihydropyridine derivatives were synthesized, the UV-vis absorption and photoluminescence of these compounds were also studied. All the compounds exhibited strong blue emissions. (λem:436-451nm). The results showed that the absorption maxima of the compounds vary from 332 to 345nm depending on the group bonded to dihydropyridines rings.
- Liu, Manman,Li, Xiao,Zhang, Jian
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p. 880 - 883
(2015/01/30)
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- Self-assembled hybrid tinphosphonate nanoparticles with bimodal porosity: An insight towards the efficient and selective catalytic process for the synthesis of bioactive 1,4-dihydropyridines under solvent-free conditions
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Self-assembled ordered mesoporous organic-inorganic hybrid tinphosphonate nanomaterial (HSnP-2) with crystalline framework structure has been synthesized through the reaction of benzene-1,3,5-triphosphonic acid (BTPA) and Sn(iv) chloride under hydrothermal conditions at 453 K in the absence of any structure directing agent. Powder XRD, FE-SEM, HR-TEM, N2 sorption, solid state 13C CP-MAS and 31P MAS NMR, TG-DTA analysis and FT-IR spectroscopic techniques are employed to characterize the material. The hexagonal crystal phase of the material is established through REFLEX and CELSIZ unit cell refinement programs. The calculated unit cell parameters of HSnP-2 are a = b = 17.515 A and c = 10.254 A. The material is composed of hexagonally ordered tiny nanocrystals of dimensions of ca. 4.0 nm and exhibits high BET surface area (380 m2 g-1), good thermal stability along with uniform supermicropores (ca. 1.3 nm) and an ordered assembly of mesopores. HSnP-2 shows outstanding catalytic activity and high recycling efficiency for the green and efficient one-pot three component coupling reaction for the synthesis of bioactive 1,4-dihydropyridines with excellent yields under solvent-free conditions. The novelty of this eco-friendly catalytic system is further manifested from the mild reaction temperature (333 K) and short reaction time (20 min), together with exclusive selectivity for the desired 1,4-dihydropyridines over 2-arylpyridines or 1,2-dihydopyridines.
- Pramanik, Malay,Bhaumik, Asim
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p. 11210 - 11220
(2013/09/23)
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- Synthesis, anticancer and MRP1 inhibitory activities of 4-alkyl/aryl-3,5-bis(carboethoxy/carbomethoxy)-1,4-dihydro-2,6-dimethylpyridines
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Fourteen new 4-alkyl/aryl-3,5-bis-(carboethoxy/carbomethoxy)-1,4-dihydro-2, 6-dimethylpyridines (4a-4n) have been prepared by conventional and microwave irradiation (MWI) methods from a three component reaction mixture viz., alkyl acetoacetate (1), appropriate aldehyde (2) and ammonium acetate (3). The compounds prepared have been purified and characterized by their spectral (FTIR, 1H NMR and MS) data. The two synthetic methods employed have been compared in terms of relative yields and reaction times. On comparison, the MWI method has been found to be easy, simple, eco-friendly, rapid and high yielding. The synthesized compounds have been evaluated for their cytotoxic activity against HT-29 (colon cancer) and MDA-MB (breast cancer) cell lines and MRP1 inhibitory activity using the insect cell membrane MRP 1 ATPase assay. Though some of the compounds could exhibit some degree of cytotoxicity it was found to be low in comparison to standard. Among the compounds tested 4g was relatively better in its MRP1 inhibitory action (IC50 = 16 μM) but not comparable to that of benzbromarone (IC50 = 4 μM).
- Amgoth, Srinivas Nayak,Porika, Mahendar,Abbagani, Sadanandam,Garlapati, Achaiah,Vanga, Malla Reddy
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p. 147 - 155
(2013/03/13)
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- A magnetic particle-supported sulfonic acid catalyst: Tuning catalytic activity between homogeneous and heterogeneous catalysis
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Surface functionalization of magnetic particles is an elegant way to bridge the gap between heterogeneous and homogeneous catalysis. The introduction of magnetic particles (MPs) in a variety of solid matrices allows the combination of well-known procedures for catalyst heterogenization with techniques for magnetic separation. We have conveniently loaded sulfonic acid groups on magnetic particles supports in which chlorosulfonic acid is used as sulfonating agent. The main targets are room temperature, solvent-free conditions, rapid (immediately) and easy immobilization technique, and low cost precursors for the preparation of highly active and stable MPs with high densities of functional groups. The inorganic, magnetic, solid acid catalyst was characterized via Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), dynamic light scattering (DLS), vibrating sample magnetometer (VSM) and titration. The catalyst is active for the Hantzsch reaction and the products are isolated in high to excellent yields (90-98%). Supporting this acid catalyst on magnetic particles offers a simple and non-energy-intensive method for recovery and reuse of the catalyst by applying an external magnet. Isolated catalysts were reused for new rounds of reactions without significant loss of their catalytic activity. Copyright
- Koukabi, Nadiya,Kolvari, Eskandar,Zolfigol, Mohammad Ali,Khazaei, Ardeshir,Shaghasemi, Behzad Shirmardi,Fasahati, Behzad
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experimental part
p. 2001 - 2008
(2012/10/08)
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- PEG-mediated catalyst-free synthesis of Hantzsch 1,4-dihydropyridines and polyhydroquinoline derivatives
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Hantzsch 1,4-dihydropyridines and polyhydroquinoline derivatives were synthesized in good yields by PEG-mediated, catalyst-free synthesis under solvent-free conditions. The products were directly recrystallized from hot methanol. The reaction gave excellent yields with low- as well as high-molecular-weight polyethylene glycols. Taylor & Francis Group, LLC.
- Siddaiah,Basha, G. Mahaboob,Rao, G. Padma,Prasad, U. Viplava,Rao, R. Suryachendra
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experimental part
p. 627 - 634
(2011/12/22)
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- 1-Methylimidazolium trifluoroacetate [Hmim]Tfa: Mild and efficient Bronsted acidic ionic liquid for Hantzsch reaction under microwave irradiation
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One pot synthesis of 1,4-dihydropyridine derivatives was achieved via condensation of various β-ketoesters with aromatic/aliphatic aldehydes and ammonium acetate. The reaction was catalysed by a stable and reusable Bronsted acidic ionic liquid (IL), 1-methyl-imidazolium trifluoroacetate ([Hmim]Tfa), under microwave (MW) irradiation. The synergistic combination ofMWwith IL can potentially go a long way tomeet the increasing demand for chemical processes. This homogeneous catalytic procedure is simple and efficient. The catalyst can be reused at least four times with almost complete retention in its activity. Indian Academy of Sciences.
- Avalani, Jemin R.,Patel, Devji S.,Raval, Dipak K.
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p. 1091 - 1096
(2013/03/13)
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- Synthesis and antioxidant activity of a series of novel 3-chalcone-substituted 1,4-dihydropyridine derivatives
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New 3-chalcone-substituted 1,4-dihydropyridine (DHP) derivatives have been synthesized based on dimethyl or diethyl 2,6-dimethyl-4-phenyl-1,4-DHP-3,5- dicarboxylate. Their structures were confirmed by IR, 1H NMR, 13C NMR, and elemental analyses. The synthesized compounds were also screened for antioxidant properties.
- Sun, Hao,Shang, Chengxiang,Jin, Longfei,Zhang, Jian
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p. 239 - 243
(2013/05/21)
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- Comparative study of various green chemistry approaches for the efficient synthesis of 1,4-dihydropyridines
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Hantzsch 1,4-dihydropyridine and its derivatives are an important class of bioactive molecules in the pharmaceutical field. The work on this project was started with the objective of synthesizing known 1,4-dihydropyridine by various green chemistry methods like microwave, solvent-free, ultrasonication and compared the results with conventional technique using different aldehydes and 1,3-dicarbonyl compounds as substituents. The twelve known 1,4-dihydropyridines were synthesized and characterized by their TLC, FT-IR and 1H NMR, elemental studies. When all the data cross-examined, it was concluded that microwave, ultrasonic and solvent-free methods were efficient and less time consuming with high yield. At the same time conventional method was time consuming but scalable when compared with other methods.
- Kaur, Prabhjot,Sharma, Heena,Rana, Rekha,Prasad, D. N.,Singh, Rajesh K.
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p. 5649 - 5651,3
(2020/09/15)
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- Microwave assisted one-pot synthesis of nitrogen and oxygen containing heterocycles from acyl Meldrum's acid
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One-pot syntheses of biologically active nitrogen and oxygen containing heterocyclic compounds such as uracils and thiouracils and 1,4-benzothiazines, 4-methylcoumarins and 4H-1,4- dihydropyridines, using acyl Meldrum's acids are reported.
- More,Mahulikar
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experimental part
p. 745 - 747
(2011/06/27)
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- Hantzsch reaction on free nano-Fe2O3 catalyst: Excellent reactivity combined with facile catalyst recovery and recyclability
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A magnetic nanoparticle catalyst was readily prepared from inexpensive starting materials which catalyzed the Hantzsch reaction. High catalytic activity and ease of recovery from the reaction mixture using an external magnet, and several reuse times without significant losses in performance are additional eco-friendly attributes of this catalytic system.
- Koukabi, Nadiya,Kolvari, Eskandar,Khazaei, Ardeshir,Zolfigol, Mohammad Ali,Shirmardi-Shaghasemi, Behzad,Khavasi, Hamid Reza
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experimental part
p. 9230 - 9232
(2011/10/03)
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- A simple and efficient one-pot synthesis of Hantzsch 1,4-dihydropyridines using silica sulphuric acid as a heterogeneous and reusable catalyst under solvent-free conditions
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A simple, inexpensive and efficient one-pot synthesis of 1,4-dihydropyridine derivatives under solvent-free conditions using silica sulphuric acid (SSA) as a heterogeneous and recyclable catalyst is reported.
- Kolvari, Eskandar,Zolfigol, Mohammad Ali,Koukabi, Nadiya,Shirmardi-Shaghasemi, Behzad
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experimental part
p. 898 - 902
(2012/03/27)
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- LiBr as an efficient catalyst for one-pot synthesis of Hantzsch 1,4-dihydropyridines under mild conditions
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A simple, inexpensive and efficient one-pot synthesis of 1,4-dihydropyridines has been accomplished via lithium bromide-catalyzed Hantzsch three-component condensation reaction of an aldehyde, αβ-ketoester and ammonium acetate in acetonitrile at room temperature in good to excellent yields. The present protocol is applicable to wide range of substrates including aliphatic, aromatic and heterocyclic aldehydes affording 1,4-dihydropyridines. A simple, inexpensive and efficient one-pot synthesis of 1,4-dihydropyridines has been accomplished via lithium bromide-catalyzed Hantzsch three-component condensation reaction of an aldehyde, αβ-ketoester and ammonium acetate in acetonitrile at room temperature in good to excellent yields. The present protocol is applicable to wide range of substrates including aliphatic, aromatic and heterocyclic aldehydes affording 1,4-dihydropyridines. Copyright
- Yadav,Patel,Srivastava,Watal,Yadav
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experimental part
p. 118 - 122
(2012/03/27)
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