- Photocatalytic Hydrogen Production from Hantzsch 1,4-Dihydropyridines by Platinum(II) Terpyridyl Complexes in Homogeneous Solution
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1,4-Dihydropyridines have been photocatalytically oxidized to pyridines by platinum(II) terpyridyl complexes with the generation of hydrogen in homogeneous solution. The hydrogen production proceeds in quantitative yield and with great catalytic turnover. Copyright
- Zhang, Dong,Wu, Li-Zhu,Zhou, Li,Han, Xue,Yang, Qing-Zheng,Zhang, Li-Ping,Tung, Chen-Ho
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- TEMPO supported amine functionalized magnetic titania: a magnetically recyclable catalyst for the aerobic oxidative synthesis of heterocyclic compounds
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Abstract: The present protocol uncover a new strategy to synthesize highly efficient solid TEMPO based catalyst in which 4-oxo-TEMPO was covalently tethered to the surface of amine functionalized magnetic titania. The chemical nature and structure of the
- Sharma, Sukanya,Choudhary, Anu,Sharma, Shally,Shamim, Tahira,Paul, Satya
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- Superparamagnetic core-shell metal–organic framework Fe3O4@Ni-MOF as efficient catalyst for oxidation of 1,4-dihydropyridines using hydrogen peroxide
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A facile and efficient method was described for oxidation of some 3,5-diacyl or 3,5-diester 1,4-dihydropyridines using H2O2 in the presence of superparamagnetic core-shell metal–organic framework Fe3O4@Ni-MOF. The Fe3O4@Ni-MOF has been obtained by Step-by-Step method in which magnetic Fe3O4 magnetic nanoparticles were coated with Ni-MOF using a mercaptoacetic acid linker. The synthesized catalyst was characterized using thermogravimetric analysis, FT-IR spectroscopy, powder X-ray diffraction, field emission scanning electron microscopy and energy-dispersive X-ray analysis. The novel superparamagnetic core-shell metal–organic framework Fe3O4@Ni-MOF revealed high efficiency for oxidation of various 1,4-dihydropyridines using hydrogen peroxide. The Box–Behnken design matrix and the response surface method were applied to investigate the optimization of the reaction conditions. The conditions for optimal reaction yield and time were: amount of catalyst ≈17 mmol, temperature ≈78°C and amount of hydrogen peroxide ≈ 1 ml. A variety of 3,5-diacyl or 3,5-diester 1,4-dihydropyridines with different substituted functional groups have been converted to corresponding pyridines with good to excellent isolated yields using H2O2 and Fe3O4@Ni-MOF. The catalyst was reused up to five times for the oxidation of 1,4-dihydropyridines without a significant loss in catalytic activity. The short reaction times, simplicity of method, good to excellent yields and reusability of catalyst were some advantages of the proposed procedure.
- Janani, Marzieh,Senejani, Masumeh Abdoli,Isfahani, Tahereh Momeni
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- Ring-contraction of hantzsch esters and their derivatives to pyrrolesviaelectrochemical extrusion of ethyl acetate out of aromatic rings
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Electrochemical ring-contraction of HEs and theirs pyridine derivatives is developed to obtain polysubstituted pyrroles. This process provides an orthogonal utilization of Hantzsch esters for the well-documented application as side chain or hydrogen donors. The formal transformation shows an extrusion of ethyl acetate out of the pyridine ring in a single step. In addition to the novel transformation, we also discovered the Lewis acid's intermolecular control of regioselectivity during an intramolecular electrochemical process. The reaction provides a number of polysubstituted pyrroles that have never been accessed, including pharmaceutical intermediates and photoswitches. An unusual 4-electron continuous reduction drives the unprecedented anionic dearomatization/ring-contraction/rearomatization pathway.
- Liu, Xu,Liu, Chang,Cheng, Xu
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supporting information
p. 3468 - 3473
(2021/05/21)
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- Method for ultrasonically oxidizing hantzsch ester 1, 4-dihydropyridine derivative
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The invention relates to the technical field of organic synthesis, and provides a method for ultrasonically oxidizing a hantzsch ester 1, 4-dihydropyridine derivative. The method comprises the following steps: under ultrasonic conditions, carrying out oxi
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Paragraph 0045-0048
(2020/02/06)
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- Trinuclear cis-dioxidomolybdenum(VI) complexes of compartmental C3 symmetric ligands: Synthesis, characterization, DFT study and catalytic application for hydropyridines (Hps) via the Hantzsch reaction
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Trinuclear cis-dioxidomolybdenum(VI) complexes of the type [{MoVIO2(MeOH)}3L1-7] (1–7) have been synthesized using tris(H2ONO) donor ligands [H6L1-7 (I–VII)] assembled from benzene-1,3,5-tricarbohydrazide (bthz) and the corresponding salicylaldehyde (sal). All the ligands and the complexes were characterized by numerous techniques, such as FT-IR, UV–visible, NMR (1H and 13C) spectroscopy, electrochemical study, elemental analysis, thermogravimetric study and single crystal X-ray diffraction of the ligand III and complexes 1 and 5. In the presence of H2O2 as an oxidant, these complexes show excellent catalytic potential towards the one-pot three-components [ethyl acetoacetate, benzaldehyde (or its derivatives) and ammonium acetate] dynamic covalent assembly in the Hantzsch reaction. Under solvent free conditions, as high as 98% conversion along with 100% selectivity towards diethyl 2,6-dimethyl-4-phenyl-1,4-dihydropyridine-3,5-dicarboxylate (1,4-DHP) has been achieved in 1 h. Although solvents do not improve the conversion, they do influence the selectivity of the products. With the elapse of time, the conversion of dihydropyridine to the diethyl 2,6-dimethyl-4-phenylpyridine-3,5-dicarboxylate derivative occurs and completes in ca. 10 h with a distinct color change, showing the importance of the catalysts. Efforts have been made to provide suitable reaction pathways for the catalytic reaction based on spectroscopic and density functional theory studies.
- Avecilla, Fernando,Gupta, Puneet,Maurya, Mannar R.,Tomar, Reshu
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supporting information
(2020/06/08)
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- Aerobic oxidative aromatization of Hantzsch 1,4-dihydropyridines via an anomeric-based oxidation in the presence of Laccase enzyme/4-Phenyl urazole as a cooperative catalytic oxidation system
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Abstract: Cooperative catalytic system of Laccase enzyme (from Trametes versicolor) and 4-phenyl urazole in phosphate buffer/acetonitrile solution at 40?°C has been applied for the biomimetic aerobic oxidative aromatization of Hantzsch 1,4-dihydropyridine
- Khaledian, Donya,Rostami, Amin,Zarei, Seyed Amir,Mohammadi, Behnaz
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p. 1871 - 1878
(2019/04/25)
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- Silica-supported ceric ammonium nitrate (CAN): a simple, mild and solid-supported reagent for quickest oxidative aromatization of Hantzsch 1,4-dihydropyridines
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An efficient and environmentally benign methodology for the oxidative aromatization of 1,4-dihydropyridines to their corresponding pyridine derivatives is developed. The oxidative aromatization of 1,4-dihydropyridines was explored using silica-supported ceric ammonium nitrate as catalyst in CH3CN with or without sonication at room temperature. This supported catalyst acts as a more efficient oxidising reagent and offers several advantages over other reported reagents in terms of reaction time and yields. The supported reagent is found to be more efficient and selective when compared with its unsupported form. The Belousov–Zhabotinskii reaction was not observed in present reaction. The dealkylation observed in case of 4-n-alkyl/n-alkenyl with other oxidising agents is also not observed in the present case.
- Kumar, Parvin,Kadyan, Kulbir,Duhan, Meenakshi,Sindhu, Jayant,Hussain, Khalid,Lal, Sohan
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p. 1153 - 1162
(2019/04/25)
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- Application of laccase/DDQ as a new bioinspired catalyst system for the aerobic oxidation of tetrahydroquinazolines and Hantzsch 1,4-dihydropyridines
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Laccase/DDQ as a new bioinspired quinone-based cooperative catalytic system was used for the biomimetic aerobic oxidative synthesis of 2-substituted quinazolines and Hantzsch pyridines from the oxidative cyclocondensation of 2-aminobenzylamine and aldehyd
- Shariati, Mastaneh,Imanzadeh, Gholamhassan,Rostami, Amin,Ghoreishy, Nadya,Kheirjou, Somayyeh
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p. 337 - 346
(2019/04/25)
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- Facile aromatisation of Hantzsch 1,4-dihydropyridines by autoxidation in the presence of p-toluenesulfonic acid in acetic acid
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A simple protocol to achieve the aromatisation of Hantzsch dihydropyridines in high yield was established using p-toluenesulfonic acid in acetic acid and yields of 90% were obtained at room temperature. With regards to the Hantzsch 1,4-dihydropyridines derived from alkyl aldehydes bearing one or more á-hydrogens, dealkylation products were obtained through a proposed autoxidation mechanism.
- Zhang, Ding,Sha, Min
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p. 141 - 144
(2018/04/20)
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- CAN mediated mechanochemical synthesis of substituted pyridine derivatives
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A simple, green and cost-effective protocol has been devised for the synthesis of 4-substituted-2,6-dimethyl-3,5-pyridinecarboxylates from Hantzsch-type 1,4-dihydropyridines via rapid oxidation in excellent yields using 1.5 equivalent of ceric ammonium nitrate within 15 minutes in solvent-free conditions. The method was able to furnish the products in excellent yields. The products obtained were characterized by their NMR and melting points data.
- Khanna, Radhika,Dalal, Aarti,Kadyan, Kulbir,Kumar, Ramesh,Kumar, Parvin,Kamboj, Ramesh C.
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p. 673 - 677
(2018/07/14)
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- One-pot synthesis of 3-hydroxy-2-oxindole-pyridine hybrids via Hantzsch ester formation, oxidative aromatization and sp3 C–H functionalization using FeWO4 nanoparticles as recyclable heterogeneous catalyst
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Synthesis of poly-substituted 3-hydroxy-2-oxindole-pyridine hybrids is reported via sp3 C–H bond functionalization as key steps using FeWO4 nanoparticles as reusable heterogeneous catalyst. Formation of Hantzsch ester (DHP) followed by aromatization, and sp3 C–H bond functionalization was achieved using FeWO4 nanoparticles (20 mol%) at 80 °C. Temperature dependent reactivity was observed for mono aldol (at 80 °C) and bis aldol (at 120 °C) products. The catalyst was regenerated and reused up to 6 cycles without losing catalytic activity. The FeWO4 nanoparticles were also used for oxidative aromatization of different DHP derivatives and for the sp3 C–H functionalization of 2-methyl pyridine.
- Paplal, Banoth,Nagaraju, Sakkani,Sathish, Kota,Kashinath, Dhurke
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p. 110 - 115
(2017/10/16)
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- For 1, 4 - dihydro pyridine compound to prepare the corresponding pyridine compound (by machine translation)
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The invention discloses a method for the 1, 4 - dihydro pyridine compound to prepare the corresponding pyridine compound. The method of the invention is: will be 1, 4 - dihydro pyridine compound, eosin Y of the four n-butyl ammonium salt, potassium carbonate is added to the organic solvent with the water in the mixed solvent of stirring and mixing, inject the air in visible light irradiation under the conditions of reaction, to be after the reaction, by adding ethyl acetate, respectively water, saturated ammonium chloride washing, removal of inorganic alkali and adjust the system to subacid, in the organic phase by adding a small amount of activated carbon to remove the pigment, then dried with anhydrous sodium sulfate, turns on lathe does, recrystallize and obtain the corresponding pyridine compound. The method of the invention compared with the prior art has to oxygen in air as the oxidizing agent, is cheap and easy to get; to sunlight as the energy source, so that the industrial production more favorable; catalytic amount of the use of non-metal catalyst, reduces the cost of synthesizing, avoiding the noble metal in the accumulation of drug in the synthesis. (by machine translation)
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Paragraph 0054-0056
(2017/08/19)
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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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- 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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- Photoinduced Aromatization of Dihydropyridines
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The combination of tris(bipyridine)ruthenium(II)/visible light/air is found to be effective for the aromatization of many dihydropyridines. A low catalyst loading of just 0.02 mol% is required.
- Lu, Zheng,Yang, Yong-Qing,Li, Hong-Xia
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supporting information
p. 4221 - 4227
(2016/11/26)
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- Direct and co-catalytic oxidative aromatization of 1,4-dihydropyridines and related substrates using gold nanoparticles supported on carbon nanotubes
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A heterogeneous catalyst was assembled by stabilization of gold nanoparticles on carbon nanotubes. The resulting nanohybrid was used in the catalytic aerobic oxidation of 1,4-dihydropyridines. The system proved very efficient on the investigated substrates either directly or in the presence of a quinone co-catalyst.
- Prakash, Praveen,Gravel, Edmond,Li, Haiyan,Miserque, Frédéric,Habert, Aurélie,Den Hertog, Martien,Ling, Wai Li,Namboothiri, Irishi N. N.,Doris, Eric
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p. 6476 - 6479
(2016/09/03)
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- Simple Br?nsted acid catalyzed C-H functionalization: Efficient access to poly-substituted pyridines
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An exceptionally simple and environmentally friendly methodology has been developed for directly functionalizing the benzylic C-H bond of the poly-substituted pyridines with aromatic imines. Simple Br?nsted acid catalysts including salicylic acid and TsOH were successfully employed. Different types of poly-substituted pyridines could be efficiently obtained with moderate yields. Traditional ways to such types of pyridines involved the aromatization of the corresponding Hantzsch 1,4-dihydropyridines, while this method greatly simplified the synthetic procedures.
- Lai, Shujun,Ren, Xuwen,Zhao, Jinzhong,Tang, Zhuo,Li, Guangxun
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supporting information
p. 2957 - 2961
(2016/07/06)
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- Ruthenium bipyridyl tethered porous organosilica: A versatile, durable and reusable heterogeneous photocatalyst
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A versatile heterogeneous photocatalysis protocol was developed by using ruthenium bipyridyl tethered porous organosilica (Ru-POS). The versatility of the Ru-POS catalyst in organo-photocatalysis was explored by (i) oxidative aromatization of Hantzsch ester, (ii) reductive dehalogenation of alkyl halides, and (iii) functional group interconversion (FGI) of alcohols to alkyl halides. This journal is
- Jana, Avijit,Mondal, John,Borah, Parijat,Mondal, Sujan,Bhaumik, Asim,Zhao, Yanli
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supporting information
p. 10746 - 10749
(2015/06/30)
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- A new oxidation system for the oxidation of Hantzsch-1,4-dihydropyridines and polyhydroquinoline derivatives under mild conditions
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A new oxidation system (Na2S2O4/TBHP) to prepare pyridine derivatives has been developed by the oxidation of 1,4-dihydropyridine derivatives and polyhydroquinoline derivatives in good to excellent yields. The procedures of the reaction were green, convenient, mild and easy work-up.
- Bai, Cui-Bing,Wang, Nai-Xing,Wang, Yan-Jing,Lan, Xing-Wang,Xing, Yalan,Wen, Jia-Long
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p. 100531 - 100534
(2015/12/05)
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- Oxidative aromatization of Hantzsch 1,4-dihydropyridines by cupric bromide under mild heterogeneous condition
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A mild heterogeneous oxidizing agent, cupric bromide has been utilized for the oxidative aromatization of Hantzsch 1,4-dihydropyridines to the corresponding pyridine derivatives in excellent yields with the isolation of products by simple work-up procedur
- Saikh, Forid,De, Rimpa,Ghosh, Somnath
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supporting information
p. 6171 - 6174
(2014/12/10)
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- 3,4-Dihydro-2H-pyran promoted aerobic oxidative aromatization of 1,3,5-trisubstituted pyrazolines and Hantzsch 1,4-dihydropyridines
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An unprecedented facile oxidation of 1,3,5-trisubstituted pyrazolines and Hantzsch 1,4-dihydropyridines (DHPs) to the corresponding pyrazoles and pyridines was observed, mediated by 3,4-dihydro-2H-pyran in air. The reaction showed excellent reactivity, functional group tolerance, and high yield without using any metal and/or halogen based oxidizing agents.
- Banerjee, Dipanwita,Kayal, Utpal,Karmakar, Rajiv,Maiti, Gourhari
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supporting information
p. 5333 - 5337
(2015/01/08)
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- Metal-free-mediated oxidation aromatization of 1,4-dihydropyridines to pyridines using visible light and air
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A metal-free and environmentally friendly aerobic aromatization photosensitized by organic dye eosin Y bis(tetrabutyl ammonium salt) (TBA-eosinY) has been developed. With the aid of K2CO3, the aerobic catalytic system converts 1,4-dihydropyridines to their corresponding pyridine derivatives efficiently under visible light irradiation (λ=450 nm) at room temperature.
- Wei, Xiaojing,Wang, Lin,Jia, Wenliang,Du, Shaofu,Wu, Lizhu,Liu, Qiang
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p. 1245 - 1250
(2015/02/05)
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- Catalytic aromatization of 1,4-dihydropyridines by radical cation salt prompted aerobic oxidation
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Aromatization of Hantzch 1,4-dihydropyridines was achieved under radical cation salt induced conditions, in which triarylamine radical cation acts as an efficient catalyst to prompt the aerobic oxidation of 1,4-DHPs in a catalytic way.
- Jia, Xiaodong,Yu, Liangliang,Huo, Congde,Wang, Yaxin,Liu, Jing,Wang, Xicun
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supporting information
p. 264 - 266
(2014/01/06)
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- Triton-X-100 catalyzed synthesis of 1,4-dihydropyridines and their aromatization to pyridines and a new one pot synthesis of pyridines using visible light in aqueous media
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A realistic and convenient synthetic method has been developed for the facile synthesis of 1,4-dihydropyridine derivatives in the presence of the non-ionic surfactant Triton X-100, in an aqueous medium at room temperature. A greener method to synthesize pyridine derivatives has also been developed by the oxidation of 1,4-dihydropyridine derivatives with almost 100% yields and also in a one pot synthesis, employing an aldehyde, ethyl acetoacetate and ammonium acetate in an aqueous micellar medium by irradiation with potassium persulphate in the presence of visible light. The one pot protocol offered excellent yields of the targeted product in a very short period of time at room temperature and the non-ionic surfactant catalyst can be recovered very easily. We also observed that during the reaction there was the formation of micelles, or micelle-like colloidal aggregates, from the non-ionic surfactant and the reaction mixture in water, measured by dynamic light scattering and visualized through an optical microscope. The process is advantageous as ammonia is generated from an ammonium salt under absolutely neutral conditions and the product purification follows a group assistant purification chemistry process (GAP).
- Ghosh, Partha Pratim,Mukherjee, Prasun,Das, Asish R.
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p. 8220 - 8226
(2013/09/02)
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- Iodobenzene diacetate (IBD) catalyzed an quick oxidative aromatization of Hantzsch-1,4-dihydropyridines to pyridines under ultrasonic irradiation
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This project was undertaken to demonstrate the potential of iodobenzene diacetate for the oxidative aromatization of Hantzch-1,4-dihydropyridines under ultrasonic irradiation. All reactions were carried out under ultrasonic irradiation and results were co
- Kumar, Parvin,Kumar, Ashwani,Hussain, Khalid
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experimental part
p. 729 - 735
(2012/05/20)
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- Oxidation of 1,4-dihydropyridines and 3,4-dihydropyrimidin-2(1H)-ones to substituted pyridines and pyrimidinones using Ca(OCl)2 in aqueous media
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1,4-Dihydropyridines and 3,4-dihydropyrimidin-2(1H)-ones obtained from the Hantzsch and Biginelli reactions undergo readily oxidative dehydrogenation by using calcium hypochlorite in very short times. These calcium stimulator drugs were oxidized under rea
- Tamaddon, Fatemeh,Razmi, Zahra
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experimental part
p. 485 - 492
(2011/04/15)
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- NaI readily mediated oxidative aromatization of hantzsch 1,4-dihydropyridines with hydrogen peroxide at room temperature: A green procedure
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The oxidative conversion of 1,4-dihydropyridines to give the corresponding pyridine derivatives in excellent yields was easily effected using the catalytic amount of NaI in combination with H2O2 (30%) as a green external oxidant. The
- Shahabi,Amrollahi,Jafari
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experimental part
p. 1052 - 1057
(2012/02/04)
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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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- Oxidative aromatization of hantzsch 1,4-dihydropyridines catalyzed by ferric perchlorate in ionic liquids with air
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A variety of Hantzsch 1,4-dihydropyridines were oxidized to the corresponding pyridines catalyzed by a catalytic amount of ferric perchlorate. The reaction was carried out in ionic liquid at room temperature, and the products were isolated in good to exce
- Liu, Dan,Gui, Jianzhou,Wang, Chan,Lu, Feng,Yang, Yulian,Sun, Zhaolin
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experimental part
p. 1004 - 1008
(2010/05/18)
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- Facile and efficient aromatization of 1,4-dihydropyridines with M(NO 3)2·XH2O, TNCB, TBAP and HMTAI and preparation of deuterium labeled dehydronifedipine from nifedipine-d3
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The easy and efficient aromatization of various 1,4-dihydropyridines was investigated using various metal nitrates, trinitratocerium(IV) bromate (TNCB), and tetrabutyl ammonium periodate (TBAP) as oxidant in acetic acid at 100 °C, as well as hexamethylenetetramine-iodine (HMTAI) reflux in methanol. The efficient conversion of nifedipine-d3 to dehydronifedipine-d 3 as an internal standard can be used in the measurement of nifedipine concentration in a body.
- Shaikh, Ajam C.,Chen, Chinpiao
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supporting information; experimental part
p. 3664 - 3668
(2010/09/04)
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- An expeditious oxidative aromatization of hantzsch 1,4-dihydropyridines to pyridines using cetyltrimethylammonium peroxodisulfate: A phase transferring oxidant
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A new approach to the use of potassium peroxodisulphate as an oxidizing reagent is proposed and applied to the case of oxidative aromatization of 1, 4-dihydropyridines with cetyltrimethylammonium peroxodisulfate, a phase transfer oxidant. We demonstrate h
- Kumar, Parvin,Kumar, Ashwani
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experimental part
p. 2299 - 2303
(2010/11/16)
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- Oxidative aromatization of hantzsch 1,4-dihydropyridines by H 2O2/V2o5 at room temperature
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A mild and highly efficient synthetic method was developed for the aromatization of 1,4-dihydropyridines employing H2O2 and 5mol% of V2O5. The reactions were carried out in CH 3CN to give pyridine compounds in excellent yields. Copyright Taylor & Francis Group, LLC.
- Su, Jinlong,Zhang, Cai,Lin, Dan,Duan, Yiqin,Fu, Xiangkai,Mu, Ruizhu
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experimental part
p. 595 - 600
(2010/04/24)
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- A novel, facile, simple and convenient oxidative aromatization of Hantzsch 1,4-dihydropyridines to pyridines using polymeric iodosobenzene with KBr
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An easy, safe, effective and handy method for oxidative aromatization of Hantzsch 1,4-dihydropyridines catalyzed by hypervalent iodine (iodosobenzene) and potassium bromide to corresponding pyridine derivatives in high-yields and within short span of time was described. Dealkylation in case of 4-n-alkyl substituted 1,4-dihydropyridines was not obtained.
- Kumar, Parvin
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experimental part
p. 1429 - 1433
(2011/02/23)
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- Biomimetic catalytic oxidation of hantsch 1,4-dihydropyridines using [Bis-(salicylaldehye)-4-methyl-1,2-phenylenediimine]-Mn(III) chloride/sodium periodate under mild conditions
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[Bis(salicylaldehye)-4-methyl-1,2-phenylenediimine]Mn(III) chloride [Mn(III)-BSMP] as biomimetic catalyst was synthesized and identified by spectral and analytical data. A variety of Hantzsch 1,4-dihyropyridines were subjected by a catalytic amount of thi
- Montazerozohori,Nasr-Esfahani,Joohari,Haghighat, Nasrin
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experimental part
p. 4249 - 4254
(2010/11/17)
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- Oxidative aromatization of Hantzsch 1,4-dihydropyridines by sodium chlorite
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Hantzsch 1,4-dihydropyridines were converted to the corresponding pyridines efficiently by sodium chlorite under mild conditions in excellent yields.
- Liao, Xiali,Lin, Wenbin,Lu, Jun,Wang, Chun
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experimental part
p. 3859 - 3861
(2010/08/20)
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- Hydride, hydrogen, proton, and electron affinities of imines and their reaction intermediates in acetonitrile and construction of thermodynamic characteristic graphs (TCGs) of imines as a molecule ID card
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(Chemical Equation Presented) A series of 61 imines with various typical structures were synthesized, and the thermodynamic affinities (defined as enthalpy changes or redox potentials in this work) of the imines to abstract hydride anions, hydrogen atoms, and electrons, the thermodynamic affinities of the radical anions of the imines to abstract hydrogen atoms and protons, and the thermodynamic affinities of the hydrogen adducts of the imines to abstract electrons in acetonitrile were determined by using titration calorimetry and electrochemical methods. The pure heterolytic and homolytic dissociation energies of the C=N π-bond in the imines were estimated. The polarity of the C=N double bond in the imines was examined using a linear free-energy relationship. The idea of a thermodynamic characteristic graph (TCG) of imines as an efficient Molecule ID Card was introduced. The TCG can be used to quantitatively diagnose and predict the characteristic chemical properties of imines and their various reaction intermediates as well as the reduction mechanism of the imines. The information disclosed in this work could not only supply a gap of thermodynamics for the chemistry of imines but also strongly promote the fast development of the applications of imines. 2009 American Chemical Society.
- Zhu, Xiao-Qing,Liu, Qiao-Yun,Chen, Qiang,Mei, Lian-Rui
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scheme or table
p. 789 - 808
(2010/04/29)
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- Electron transfer-induced aromatization of 1,4-dihydropyridines
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A wide variety of 3,5-dicarboethoxy-1,4-dihydropyridines and 3,5-diacetyl-1,4-dihydropyridines are aromatized to the pyridine derivatives by 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) at room temperature and under microwave irradiation. An electron tra
- Memarian, Hamid R.,Ghazaie, Marieh,Mehneh, Somayeh Kakhki
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experimental part
p. 1187 - 1192
(2010/03/01)
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- Oxidative aromatization of 1,4-dihydropyridines and pyrazolines using HbA-H2O2: An efficient biomimetic catalyst system providing metabolites of drug candidates
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Human hemoglobin (HbA) efficiently catalyses the oxidative aromatization of 1,4-dihydropyridines (1,4-DHPs) and pyrazolines with hydrogen peroxide in phosphate buffer. The results of the study reveal that the rates of oxidative aromatization of 1,4-DHPs a
- Kumar, Atul,Maurya, Ram Awatar,Sharma, Siddharth
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scheme or table
p. 4432 - 4436
(2010/04/05)
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- Efficient oxidation of hantzsch 1,4-dihydropyridines with tetrabutylammonium peroxomonosulfate catalyzed by manganese(III) schiff base complexes: The effect of schiff base complex on the product selectivity
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Efficient and rapid oxidation of Hantzsch 1,4-dihydropyridine with tetrabutylammonium peroxomonosulfate (TBAO) is reported. The Mn(salophen)/monopersulfate catalytic system efficiently converts 1,4-dihydropyridines (DHPs) to their corresponding pyridine d
- Nasr-Esfahani, Masoud,Moghadam, Majid,Valipour, Ghasem
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experimental part
p. 3867 - 3879
(2009/12/24)
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- β-Cyclodextrin-catalyzed mild aromatization of hantzsch 1,4-dihydropyridines with o-iodoxybenzoic acid in water/acetone
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Hantzsch 1,4-dihydropyridines undergo smooth aromatization oxidized by o-iodoxybenzoic acid (IBX) in water/acetone in the presence of-cyclodextrin (-CD) to afford the corresponding pyridine derivatives in excellent yields. The IBX and-CD can be recycled and reused.
- Chen, Jiang-Min,Zeng, Xiao-Mei
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experimental part
p. 3521 - 3526
(2010/02/28)
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- Aromatization of Hantzsch 1,4-dihydropyridines in solventless system using Glycinium chlorochromate
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Glycinium chlorochromate (GCC) supported onto silica gel was used as an effective oxidizing agent for the aromatization of 1,4-dihydropyridines to corresponding pyridine.
- Hekmatshoar, Rahim,Rezaei, Akram,Haghighi, Masoumeh,Ojghaz, Azadeh Jafari,Sajadi, Sodeh
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experimental part
p. 40 - 42
(2010/04/05)
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- A simple, efficient, one-pot three-component domino synthesis of Hantzsch pyridines under solvent-free condition
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(Chemical Equation Presented) In this article, efficient and simple preparation of Hantzsch pyridine derivatives by reaction of various aldehydes and β-dicarbonyls in the presence of ammonium chlorate under solvent-free condition at 80°C is reported. The advantages of this system are the one-step procedure, high yields of the products, and the ability to carry out large-scale reactions.
- Nasr-Esfahani, Masoud,Karami, Bahador,Behzadi, Masoume
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experimental part
p. 931 - 935
(2009/12/03)
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- N-Nitroso-2-aryl-1,3-oxazolidines catalyzed aromatization of Hantzsch 1,4-dihydropyridines
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A catalytic amount of N-nitroso-2-aryl-1,3-oxazolidines leading to the aromatization of Hantzsch 1,4-dihydropyridines (DHPs) was successfully achieved. A catalytic mechanism for the reaction is proposed.
- Peng, Li-jun,Wang, Jian-tao,Lu, Zhou,Liu, Zhong-quan,Wu, Long-min
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p. 1586 - 1588
(2008/09/18)
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- KHSO4 supported onto bentonite, a versatile reagent for aromatization of Hantzsch 1,4-dihydropyridines
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Aromatization of Hantzsch 1,4-dihydropyridines was promoted by KHSO 4, a relatively green chemical, supported onto bentonite to yield the corresponding pyridine derivatives in excellent yields. The reaction was carried out under mild and conven
- Heravi, Majid M.,Bakhtiari, Khadijeh,Oskooie, Hossein A.
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p. 579 - 581
(2008/02/11)
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- A facile aromatisation of 1,4-dihydropyridines by ammonium nitrate in acetic acid
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The oxidation of 1,4-dihydropyridines to pyridines with ammonium nitrate as an oxidant in the presence of acetic acid proceeds in excellent yield.
- Awachat, Moreshwar M.,Shaikh, Ajam C.,Ganjave, Nitin V.,Chavan, Subhash P.,Shivakumar,Kalkote, Uttam R.
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p. 193 - 194
(2008/02/09)
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- New strategy for the oxidation of Hantzsch 1,4-dihydropyridines and dihydropyrido[2,3-d]pyrimidines catalyzed by DMSO under aerobic conditions
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A novel metal-salt-oxidant-free, efficient, and economical method for the oxidation of Hantzsch 1,4-dihydropyridines that uses aerial oxygen and solvent-grade dimethylsulfoxide is described. Also, the synthesis of pyrido[2,3-d]pyrimidines is achieved from in situ oxidation of dihydropyrido[2,3-d]pyrimidines that arise from the reaction of 6-aminouracils and cyano olefins in dimethylsulfoxide. Copyright Taylor & Francis Group, LLC.
- Saini, Anil,Kumar, Sanjay,Sandhu, Jagir S.
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p. 2317 - 2324
(2008/02/09)
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- Catalytic oxidation of 1,4-dihydropyridins by tetrabutylammonium periodate in the presence of manganese amino acid Schiff base
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The amino acid Schiff base manganese complex (Tryp-Mn); 1, was prepared with L-tryptophan, salicylaldehyde and Mn(OAc)2.4H2O in methanol. In the presence of 1, 1,4-dihydropyridines (1,4-DHPs) were oxidised by n-Bu4NIO
- Karimipour, Gholam Reza,Nasr-Esfahani, Masoud,Valipour, Ghasem
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p. 415 - 417
(2008/02/12)
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- Siver salts/ iodine monochloride as a new oxidation system for the oxidative aromatization of 1, 4-dihydropyridines
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Silver salts such as silver nitrate and silver oxide have been found to promote oxidative aromatization of various 1, 4-dihydropyridines to their corresponding pyridine derivatives by iodine monochloride under heterogeneous conditions in dichloromethane a
- Montazerozohori, Morteza,Karami, Bahador,Nasr-Esfahani, Masoud,Musavi, Sayed Alireza
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p. 289 - 294
(2008/03/13)
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