- 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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- [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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- Green synthesis and characterization of novel Mn-MOFs with catalytic and antibacterial potentials
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This study focused on the synthesis of a new manganese-based metal-organic framework and the investigation of its application aspects. A Mn-MOF nanostructure, namely UoB-4, was prepared using a Schiff base organic linker (H2bbda: 4,4′-[benzene-
- Aryanejad, Sima,Bagherzade, Ghodsieh,Moudi, Maryam
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p. 1508 - 1516
(2020/02/06)
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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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- 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.
- -
-
Paragraph 0126; 0127
(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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- 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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- Erbium-Organic Framework as Heterogeneous Lewis Acid Catalysis for Hantzsch Coupling and Tetrahydro-4H-Chromene Synthesis
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Abstract: An Erbium-organic framework was prepared by hydrothermal reaction. The prepared framework was characterized by Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), and X-ray powder diffraction (XRD). The framework has open metal sites at Er(III) centers, thus providing an accessible Lewis acid center for electrophile activation. Accordingly, the synthesized framework was used as Lewis acid heterogeneous catalyst for Hantzsch coupling reaction and tetrahydro-4H-chromene synthesis. The reaction condition has been optimized by variation of the reaction time, temperature, solvent and catalyst concentration. A variety of tetrahydro-4H-chromenes was synthesized and characterized by FT-IR and1H NMR spectroscopy. Er-MOF, as a Lewis acid heterogeneous catalyst, showed excellent selectivity and high yield for these transformations. Graphical Abstract: [Figure not available: see fulltext.]
- Hajiashrafi, Taraneh,Karimi, Meghdad,Heydari, Akbar,Tehrani, Alireza Azhdari
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p. 453 - 462
(2017/02/18)
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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
-
supporting information
p. 4046 - 4049
(2016/08/18)
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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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- Synthesis of 1,4-dihydropyridine esters using low-melting sugar mixtures as green solvents
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Several low-melting sugar mixtures (LMMs) were synthesized and used for preparation of 1,4-dihydropyridines with aldehydes, 1,3-dicarbonyl compounds, and a nitrogen source as starting materials. Good yields, low reaction times, recyclability of LMMs, and catalyst-free methodology are some of the highlights of this new protocol.
- Kumar, J. Ashwin,Shridhar, Gomathi,Ladage, Savita,Ravishankar, Lakshmy
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supporting information
p. 1989 - 1998
(2016/12/09)
-
- 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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- 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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p. 1810 - 1813
(2016/07/16)
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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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- First Report About the Use of Micellar Keggin Heteropolyacids as Catalysts in the Green Multicomponent Synthesis of Nifedipine Derivatives
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Abstract: Micellar Keggin heteropolyacid catalysts were prepared using hexadecyltrimethylammonium bromide (cetyltrimethylammonium bromide—CTAB), 1-hexadecyl-pyridinium chloride, and Keggin heteropolyacids H3PMo12O40 and H4PMo11VO40 as precursors. Four catalysts were prepared (PMo12C16, PMo11VC16, PMo12C16Py, and PMo11VC16Py) and characterized by 31P NMR, FT-IR, XRD, SEM analysis and textural properties (SBET). The acidic characteristics of the catalysts were determined by potentiometric titration with n-butylamine. A series of bioactive 1,4-dihydropyridine derivatives such as nifedipine and nemadipine B were synthesized using these new materials, in a one-pot procedure in ethanol. This methodology requires a reaction time of 8?h, and a temperature of 78?°C to obtain good to excellent yields of 1,4-dihydropyridine derivatives. The micellar Keggin catalysts are insoluble in polar media, which allows easy removal of the reaction products without affecting their catalytic activity. The leaching test showed that they have an excellent stability and can be used five times as heterogeneous catalysts without appreciable loss of the catalytic activity. Using the same material, unsymmetrical 1,4-dihydropyridines such as nitrendipine can be obtained through a sequence of steps in very good yield (78?%). Graphical Abstract: [Figure not available: see fulltext.]
- Palermo, Valeria,Sathicq, ángel G.,Constantieux, Thierry,Rodríguez, Jean,Vázquez, Patricia G.,Romanelli, Gustavo P.
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p. 1634 - 1647
(2016/08/30)
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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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- 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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- 1,4-Dihydropyridine Cationic Peptidomimetics with Antibacterial Activity
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We synthesized new broad spectrum antibacterial cationic peptidomimetics centered on a hydrophobic 1,4-dihydropyridine (1,4-DHP) scaffold. The synthesis involves the preparation of the scaffold in a three step Hantzsch reaction followed by simultaneous coupling of the 1,4-DHP scaffold to two dipeptides bearing cationic side chains. The synthesized peptidomimetics were found to have no measurable toxic hemolytic effect against mammalian red blood cells. The compounds were found to have antibacterial activity against Gram-(-) and Gram-(+) bacteria with MICs in the range of 35-100 μg/mL. These cationic antimicrobial peptidomimetics will lead to more effective antibacterial drug candidates based on a synthetically accessible scaffold.
- Lapidot, Inbal,Albeck, Amnon,Gellerman, Gary,Shatzmiller, Shimon,Grynszpan, Flavio
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p. 243 - 247
(2015/08/06)
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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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- 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
-
-
- Multicomponent diversity-oriented synthesis of symmetrical and unsymmetrical 1,4-dihydropyridines in recyclable glycine nitrate (GlyNO 3) ionic liquid: A mechanistic insight using Q-TOF, ESI-MS/MS
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Multicomponent reactions are compelling strategies for generating a chemically diverse set of multifunctionalized heterocyclic motifs with high atom economy, rendering the transformations green. These strategies can further become more prolific if catalyst recyclability, compatibility and exploration of precise mechanistic pathways are considered. To this end, an inexpensive and recyclable glycine nitrate (GlyNO3) ionic liquid has been efficiently employed to obtain diversely substituted symmetrical and unsymmetrical 1,4-dihydropyridines with up to 93% yields via three and four components, respectively. The catalyst recyclability and compatibility to obtain both symmetrical and unsymmetrical 1,4 DHPs under identical reaction conditions are added benefits to its practical utility. Furthermore, progress of the reaction was monitored by Q-TOF, direct infusion electrospray ionization mass spectrometry (ESI-MS), and key cationic intermediates involved in the reaction have been further identified by a tandem MS experiment (Q-TOF, ESI-MS/MS), which served as the proof of concept to the mechanistic model. This is the first report which revealed that the Hantzsch reaction predominantly follows the diketone pathway among four competing reaction pathways. the Partner Organisations 2014.
- Kumar, Rajesh,Andhare, Nitin H.,Shard, Amit,Richa,Sinha, Arun Kumar
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p. 19111 - 19121
(2014/05/20)
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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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- 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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- One-pot synthesis of hantzsch dihydropyridine catalyzed by ionic liquid (BmimOAc) and the oxidative aromatization of dihydropyridine using FeCl 3·6H2O
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A series of 1,4-dihydropyridines were synthesized in one pot synthesis with the yield of 80-93 % using ionic liquid [bmim]OAc as catalyst and DMF as solvent. The ionic liquid could be repeatedly utilized 5 times with no decrease of the yield. The aromatization of these dihydropyridines (4a, 4b, 4d, 4f, 4h and 4i) were executed by the action of iron chloride and the post-processing was simplified using ethanol instead of water in dissolving dihydropyridines.
- Liu, Ruidong,Zhang, Jian
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experimental part
p. 1743 - 1746
(2011/12/22)
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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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- Nano aluminium nitride as a solid source of ammonia for the preparation of hantzsch 1,4-dihydropyridines and bis-(1,4-dihydropyridines) in water via one pot multicomponent reaction
-
Nano aluminium nitride in the presence of water acts as solid source of ammonia, which is used for the preparation of 1,4-dihydropyridines and bis-(1,4-dihydropyridines). An efficient and simple procedure for the one-pot synthesis of 1,4-dihydropyridine and bis-(1,4-dihydropyridine) derivatives was achieved by combination of methyl acetoacetate or ethyl acetoacetate with aldehydes or dialdehydes and aluminium nitride at 80 °C in water in high purity and good yields.
- Ghorbani-Choghamarani, Arash,Zolfigol, Mohammad Ali,Hajjami, Maryam,Goudarziafshar, Hamid,Nikoorazm, Mohsen,Yousefi, Somaieh,Tahmasbi, Bahman
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experimental part
p. 525 - 531
(2011/10/18)
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- Synthesis of 3,4-dihydropyrimidin-2(1H)-ones and 1,4-dihydropyridines using ammonium carbonate in water
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Various known and new 3,4-dihydropyrimidin-2(1H)-ones and 1,4-dihydropyridines are prepared efficiently via Biginelli and Hantzsch reactions using ammonium carbonate in water. Competition between Biginelli and Hantzsch reactions is observed with pyridine carbaldehydes. Using this methodology, Hantzsch esters are synthesized in higher yields and purities than with other procedures without the use of a catalyst or an organic solvent.
- Tamaddon, Fatemeh,Razmi, Zahra,Jafari, Abbas Ali
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experimental part
p. 1187 - 1189
(2010/04/23)
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- Sulfonic acid-functionalized silica: A remarkably efficient heterogeneous reusable catalyst for the one-pot synthesis of 1, 4-dihydropyridines
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An efficient one-pot method for the synthesis of 1, 4-dihydropyridines from β-dicarbonyl compounds, aldehyde, and ammonium acetate is reported using sulfonic acid-functionalized silica at 90 ° C under solvent-free conditions with good to excellent yields. The catalyst is easily prepared, stable (up to 300 ° C), reusable, and efficiently used under reaction conditions. tuebitak.
- Mohammadi, Behzad,Hosseini Jamkarani, Sayyed Mohammad,Kamali, Taghi A.,Nasrollahzadeh, Mahmoud,Mohajeri, Ali
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experimental part
p. 613 - 619
(2010/11/05)
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- In situ coupled oxidation cycle catalyzed by highly active and reusable Pt-catalysts: Dehydrogenative oxidation reactions in the presence of a catalytic amount of o-chloranil using molecular oxygen as the terminal oxidant
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An in situ coupled oxidation cycle that allows catalytic oxidation of a substrate with catalytic amounts of o-chloranil and novel reusable polymer-immobilized platinum nanocluster catalysts using molecular oxygen as the terminal oxidant was developed.
- Miyamura, Hiroyuki,Maehata, Kanako,Kobayashi, Shu
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supporting information; experimental part
p. 8052 - 8054
(2011/01/03)
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- Aromatization of hantzsch 1,4-dihydropyridines with Al(NO 3)39H2O and/or Fe(NO3)39H2O in the presence of silica sulfuric acid under mild and heterogeneous conditions
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A simple and convenient method for the aromatization of Hantzsch 1,4-dihydropyridines to the corresponding pyridines is achieved via combination of aluminum or ferric nitrates and silica sulfuric acid as environmentally friendly and novel oxidizing media.
- Ghorbani-Choghamarani, Arash,Zeinivand, Javad
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scheme or table
p. 2457 - 2463
(2010/09/05)
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- Gallium(III) chloride as an efficient new catalyst for the production of Hantzsch 1,4-dihydropyridines
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Hantzsch 1,4-dihydropyridines (DHPs) are synthesized in good to excellent yields from aldehydes, 1,3-dicarbonyl compounds and ammonium acetate using gallium(III) chloride which acts as dehydrating agents and 5 mol% is enough for this protocol under solvent free conditions.
- Kumar, Dhruva,Saini, Anil,Suresh,Sandhu, Jagir S.
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experimental part
p. 996 - 1000
(2010/07/09)
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- New efficient protocol for the production of hantzsch 1,4-dihydropyridines using RuCl3
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Hantzsch 1,4-dihydropyridines are synthesized in a few minutes and in good to excellent yields from aldehydes, 1,3-dicarbonyl compounds, and ammonium acetate. The reaction is performed in solvent-free conditions, and 5mol% of RuCl3 is enough for this protocol.
- Kumar, Dhruva,Sandhu, Jagir S.
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experimental part
p. 1957 - 1965
(2009/10/09)
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- Synthesis, characterization and anticonvulsant activity evaluation of some 1,4-dihydropyridines and 3,5-(substituted)oxycarbonyl-1,4-dihydro-2,6-dimethyl- n- [2-(4-sulfamoylphenylamino)-acetyl]-4-(substituted)pyridines
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A series of 3,5-(substituted)oxycarbonyl-1,4-dihydro-2,6-dimethyl-4- (substituted)pyridines (1a-j) were synthesized by Hantzsch method for pyridine synthesis. Treatment with chloroacetyl chloride produced N-(2-chloroacetyl)-3,5- (substituted)oxycarbonyl-1,4-dihydro-2,6-dimethyl-4-(substituted)pyridines (2a-e), which on further treatment with sulfanilamide resulted in 3,5-(substituted)oxycarbonyl-1,4-dihydro-2,6- dimethyl-N-[2-(4- sulfamoylphenylamino)-acetyl]-4-(substituted)pyridines (3a-e). The structures has been established on the basis of spectral (IR, 1H-NMR, mass) and elemental analysis. Compounds 1a-j and 3a-e (5 mg/kg and 10 mg/kg) were evaluated for their anticonvulsant effect against pentylenetetrazole-induced convulsions with diazepam (4 mg/kg) as the reference. Compounds 3a-e exhibited significant (p 0.01) anticonvulsant activity compared to the control.
- Subudhi, Bharat Bhusan,Panda, Prasanna K.,Swain, Sarada P.,Sarangi, Priyambada
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experimental part
p. 147 - 153
(2009/06/28)
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- Hantzsch synthesis of polyhydroquinolines - A simple, efficient and neat protocol
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A variety of polyhydroquinolines have been synthesized under eco-benign conditions. The reaction proceeds smoothly without any catalyst at room temperature in short reaction time. The yields and purity are excellent.
- Arumugam, Pandurangan,Perumal, Paramasivan T.
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p. 1084 - 1090
(2008/12/23)
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- An efficient, metal-free, room temperature aromatization of Hantzsch-1,4-dihydropyridines with urea-hydrogen peroxide adduct, catalyzed by molecular iodine
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A mild, highly efficient and metal-free synthetic method for aromatization of 1,4-dihydropyridines employing urea-hydrogen peroxide adduct as oxidant catalyzed by 20 mol % of molecular iodine was developed. The reaction was carried out in ethyl acetate at room temperature and the products were isolated in high to excellent yields. A plausible free-radical mechanism is proposed based on results obtained with derivatives having alkyl and aryl substituents in the 1,4-dihydropyridine ring.
- Filipan-Litvi?, Mirela,Litvi?, Mladen,Vinkovi?, Vladimir
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p. 5649 - 5656
(2008/09/21)
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- Covalently anchored sulfonic acid on silica gel as an efficient and reusable heterogeneous catalyst for the one-pot synthesis of Hantzsch 1,4-dihydropyridines under solvent-free conditions
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A highly efficient one-pot synthesis of Hantzsch 1,4-dihydropyridines under solvent-free conditions catalyzed by sulfonic acid covalently anchored onto the surface of silica gel is reported here. All types of aldehydes, including aromatic, unsaturated, and heterocyclic aldehydes, gave excellent yields. The silica gel/sulfonic acid catalyst (SiO2-SO3H) is completely heterogeneous and can be recycled for eight consecutive runs without significant loss of activity. Georg Thieme Verlag Stuttgart.
- Gupta, Raman,Gupta, Rajive,Paul, Satya,Loupy, Andre
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p. 2835 - 2838
(2008/03/13)
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- Hantzsch synthesis of 2,6-dimethyl-3,5-dimethoxycarbonyl-4-(o- methoxyphenyl)-1,4-dihydropyridine; a novel cyclisation leading to an unusual formation of 1-amino-2-methoxycarbonyl-3,5-bis(o-methoxyphenyl)-4-oxa- cyclohexan-1-ene
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Hantzsch condensation of two equivalents of methyl-3-aminocrotonate with (m- and p)-methoxybenzaldehyde afforded the expected products 2,6-dimethyl-3,5-dimethoxycarbonyl-4-(m-methoxyphenyl)-1,4-dihydropyridine and 2,6-dimethyl-3,5-dimethoxycarbonyl-4-(p-methoxyphenyl)-1,4-dihydropyridine, whereas o-methoxybenzaldehyde produced mainly 1-amino-2-methoxycarbonyl-3,5- bis(o-methoxy-phenyl)-4-oxa-cyclohexan-1-ene. The structure of the product, not previously reported in the literature, was determined by 1D and 2D NMR spectra and its MS fragmentation. This is the first example of cyclisation leading to a substituted pyran rather than 1,4-DHP under typical Hantzsch reaction conditions. A plausible mechanism for its formation is postulated.
- Filipan-Litvic, Mirela,Litvic, Mladen,Cepanec, Ivica,Vinkovic, Vladimir
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p. 2546 - 2558
(2008/03/14)
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- Rapid and cleaner synthesis of 1,4-dihydropyridines in aqueous medium
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The present investigation deals with a novel water soluble Lewis acid complex, Zn[(L)proline]2 catalyzed Hantzsch 1,4-dihydropyridine derivatives syntheses in aqueous medium assisted by microwave irradiation. The microwave promoted syntheses in aqueous medium afforded moderate to excellent yield (up to 98%) within short reaction time and allowed the reaction to take place with low microwave power (200 W). This synthetic methodology provides easier separation of products and the catalyst exhibits recycling ability without loss of its catalytic activity up to five reaction cycles.
- Sivamurugan,Vinu,Palanichamy,Murugesan
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p. 267 - 271
(2007/10/03)
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- Ultrasound-accelerated synthesis of 1,4-dihydropyridines in an ionic liquid
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Hantzsch 1,4-dihydropyridine compounds were synthesized efficiently in high yields at room temperature within short times in 1,1,3,3-N,N,N′,N′- tetramethylguanidinium trifluoroacetate as ionic liquid using ultrasound irradiation. The ionic liquid can be recovered conveniently and reused efficiently. Springer-Verlag 2006.
- Shaabani, Ahmad,Rezayan, Ali H.,Rahmati, Abbas,Sharifi, Masoumeh
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- Microwave-assisted oxidative aromatization of Hantzsch 1,4-dihydropyridines using manganese dioxide
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4-Aryl- and 4-alkyl-1,4-dihydropyridines, prepared by microwave-assisted Hantzsch reaction, are readily and efficiently aromatized in only one minute using commercial manganese dioxide in the absence of an inorganic support at 100 °C under microwave irradiation. This rapid procedure is more efficient than microwave-assisted aromatization using Pd/C, iodine or o-iodoxybenzoic acid (IBX) and gives the dehydrogenated or 4-dealkylated product in 91-100% yield (13 examples). Georg Thieme Verlag Stuttgart.
- Bagley, Mark C.,Lubinu, M. Caterina
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p. 1283 - 1288
(2007/10/03)
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- Microwave-assisted synthesis of antimicrobial dihydropyridines and tetrahydropyrimidin-2-ones: Novel compounds against aspergillosis
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Ten 4-aryl-1,4-dihydropyridine and three 4-aryl-1,2,3,4- tetrahydropyrimidin-2-one derivatives have been synthesized and examined for their activity against pathogenic strains of Aspergillus fumigatus and Candida albicans. Although none of the three compo
- Chhillar, Anil K.,Arya, Pragya,Mukherjee, Chandrani,Kumar, Pankaj,Yadav, Yogesh,Sharma, Ajendra K.,Yadav, Vibha,Gupta, Jyotsana,Dabur, Rajesh,Jha, Hirday N.,Watterson, Arthur C.,Parmar, Virinder S.,Prasad, Ashok K.,Sharma, Gainda L.
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p. 973 - 981
(2007/10/03)
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- Synthesis of substituted 1,4-dihydropyridines in water using phase-transfer catalyst under microwave irradiation
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The synthesis of various substituted 1,4-dihydropyridines has been achieved by the reaction of aldehydes, ethyl/methyl acetoacetates, and ammonium acetate in water using phase-transfer catalyst under microwave irradiation. Compared to the classical Hantzsch's reaction conditions, this new method consistently has the advantage of good yields and short reaction times. Bifunctional compounds containing two units have been synthesized using dialdehyde as precursor in good yields.
- Salehi, Hojatollah,Guo, Qing-Xiang
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p. 4349 - 4357
(2007/10/03)
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- Synthesis of hantzsch 1,4-dihydropyridines under microwave irradiation
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Biologically active substituted 1,4-dihydropyridines have been synthesized in excellent yields by the reaction of aldehydes, ethyl or methyl acetoacetic ester and ammonium acetate under microwave irradiation (MWI) within 0.75-3 min.
- Anniyappan, Marimuthu,Muralidharan,Perumal, Paramasivan T.
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p. 659 - 663
(2007/10/03)
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- Reaction of N-vinylic phosphazenes derived from β-amino acids with aldehydes. Azadiene-mediated synthesis of dihydropyridines, pyridines, and polycyclic nitrogen derivatives
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Enamino phosphonium salts 2 are obtained by 1,2-addition of hydrogen chloride to N-vinylic phosphazenes 1 derived from triphenylphosphine. Aza- Wittig reaction of phosphazenes 1 derived from triphenylphosphine and 6 derived from diphenylmethylphosphine with aldehydes 3 leads to the formation of 2-azadienes 7. Reaction of azadienes 7 with enamines affords dihydropyridines 9 and 11, pyridines 12, and bicyclic nitrogen heterocycles 15-18 in a regioselective fashion, while heterodiene 20 reacts in the same way with pyrrolidinocyclohexanone giving 1-azaphenanthrene compound 21. Reaction of enamino phosphonium salts 2 with aldehydes 3 gives symmetrical dihydropyridines 5.
- Palacios, Francisco,Herran, Esther,Rubiales, Gloria
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p. 6239 - 6246
(2007/10/03)
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- Synthesis of 1,4-dihydropyridine derivatives having an oxy-, alkoxy-, or dimethylaminophenyl substituent in the 4 position, their antioxidant activity, and their binding to phospholipid membranes
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The method of Hantzsch was used to synthesize esters and amides of 2,6-dimethyl-4-aryl- 1,4-dihydropyridine-3,5-dicarboxylic acid, containing electron donor substituents in the phenyl ring. It was found that in addition to their antioxidant properties, 3,5-diamides and 4-(3′,4′-dioxyphenyl) derivatives have an affinity for model phospholipid membranes. 1997 Plenum Publishing Corporation.
- Plotnietse,Tirzitis,Uldrikis,Koronova,Tirzite,Makarova,Duburs
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p. 1166 - 1172
(2007/10/03)
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- Rate enhancement in the synthesis of some 4-aryl-1,4-dihydropyridines using methyl 3-aminocrotonate, under microwave irradiation
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The potential of domestic microwave oven has been utilised to accelerate the Hantzsch synthesis of 4-aryl-1,4-dihydro-2,6-dimethylpyridine-3,5-dicarboxylic acid dimethyl esters (1).Similar or higher yieldss are obtained in much lesser time than that obtained in conventional methods.
- Khadilkar, B. M.,Chitnavis, A. A.
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p. 652 - 653
(2007/10/03)
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- Aqueous hydrotrope solution as a safer medium for microwave enhanced Hantzsch dihydropyridine ester synthesis
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Hantzsch esters are prepared for the first time, by condensing alkyl β-aminocrotonate, aldehyde and alkyl acetoacetate in aqueous sodium butylmonoglycosulphate (NaBMGS) as a safe reaction medium in an unmodified domestic microwave oven.
- Khadilkar, Bhushan M.,Gaikar, Vilas G.,Chitnavis, Ashish A.
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p. 8083 - 8086
(2007/10/02)
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