- Silica gel an efficient catalyst for one-pot synthesis of pyrazines from ethylenediamine and 1, 2-diketones and their analogs
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A straightforward one-pot synthesis of pyrazines from ethylenediamine and 1, 2-diketones/ α-hydroxy ketone/α-bromo ketone under solvent-free conditions at room temperature is described. This environmentally benign process has the edge on previous methods in respect of workup procedure, ease and cost of reaction, and use and generation of hazardous substances. The catalyst is recovered, characterized, and proved to be recyclable for successive four runs examined with appreciable conversions.
- Chakraborty, Rakesh Ranjan,Singha, Rabindranath,Ghosh, Pranab
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p. 373 - 378
(2018/09/29)
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- Clean and green approach for one-pot synthesis of pyrazines from Eth-ylenediamine and 1,2-diketone or its analogues under neat reaction condition
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Background: Compounds having N-heterocyclic moieties are of huge importance in the field of agrochemical, pharmaceutical, biological, fragrances, etc. Due to a lot of applications associated with pyrazine moieties, their synthesis has always been important for organic chemists. Method: Surfeit synthetic methodologies are documented in literature. Most of the methodologies used expensive solvents, harmful metal catalyst and all suffer from rigorous work-up procedures. An efficient, environmentally benign methodology, needs to be developed. We mixed ethylenediamine (2mmol) with 1, 2-diketone(1mmol), later, α-hydroxy ketone and α-bromo ketone on magnetic stirrer at room temperature under neat reaction condition for 5 to 10 hrs. Results: After purification by column chromatography using silica gel(60-120 mesh) and pet-ether, et-hylacetate mixture as eluent, we achieved pyrazine derivatives from moderate to high yield. Conclusio n: Efficient and clean procedure for one-pot preparation of pyrazines from ethylenediamine and 1, 2-diketones or with α-hydroxy ketone or with α-bromo ketone has been carried out under neat reaction condition at room temperature. Environmentally benign process furnishing moderate to excellent yields of the product and simple work-up giving pure products are special features of this reaction.
- Ghosh, Pranab,Chakraborty, Rakesh Ranjan
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p. 566 - 570
(2017/09/29)
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- Synthesis of Chiral Piperazines via Hydrogenation of Pyrazines Activated by Alkyl Halides
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A facile method has been developed for the synthesis of chiral piperazines through Ir-catalyzed hydrogenation of pyrazines activated by alkyl halides, giving a wide range of chiral piperazines including 3-substituted as well as 2,3- and 3,5-disubstituted
- Huang, Wen-Xue,Liu, Lian-Jin,Wu, Bo,Feng, Guang-Shou,Wang, Baomin,Zhou, Yong-Gui
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supporting information
p. 3082 - 3085
(2016/07/13)
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- γ-Maghemite-silica nanocomposite: A green catalyst for diverse aromatic N-heterocycles
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γ-Maghemite-silica nanocomposite has been applied as a green catalyst to synthesize variety of aromatic N-heterocycles under solvent free conditions. Characterization was done by modern analytical tools (UV, IR, AAS, DSC, EDXRF, powdered XRD, EPR, Mo?ssbauer and TEM). Mild reaction conditions and recyclability have made the present protocol both environmentally and economically viable.
- Ghosh, Pranab,Mandal, Amitava,Subba, Raju
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p. 146 - 152
(2013/09/02)
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- Catalyst-free protocol for the synthesis of quinoxalines and pyrazines in PEG
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A facile and simple catalyst-free protocol has been developed for the condensation of 1,2-diketones with aromatic 1,2-diamines in polyethylene glycol (PEG), providing quinoxaline derivatives in good yields. The important features of the methodology are broad substrates scope, simple workup, catalyst free, environmentally benign, and no requirement for metal catalysts. It is noteworthy that the cyclization reaction of 1,2-diketones with aliphatic 1,2-diamines is also conducted smoothly to afford pyrazines in good yields under the standard conditions. In addition, PEG could be recovered easily and was reused without evident loss in activity
- Huang, Tie-Qiang,Qu, Wen-Yan,Ding, Jin-Chang,Liu, Miao-Chang,Wu, Hua-Yue,Chen, Jiu-Xi
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p. 293 - 297
(2013/06/05)
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- YbCl3-catalyzed one-pot synthesis of dihydropyrazines, piperazines, and pyrazines
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A simple and efficient synthetic approach to dihydropyrazines via YbCl 3-catalyzed reaction of α-hydroxyketones with diamines under mild conditions was developed. The corresponding 2,3-subsitituted piperazines and pyrazines were obtained through tandem conversion of dihydropyrazines with good yields.
- Fan, Liyan,Chen, Wen,Qian, Changtao
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p. 231 - 234
(2013/02/23)
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- Organometallic complex and light emitting element, light emitting device, and electronic device using the organometallic complex
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To provide an organometallic complex by which red-color light emission can be obtained. In addition, to provide an organometallic complex with high light emission efficiency. Further, to provide an organometallic complex by which red-color light emission with high luminous efficiency can be obtained. An organometallic complex having a structure represented by the following general formula (G1) is provided. (In the formula, A represents an aromatic hydrocarbon group having 6 to 25 carbon atoms. Further, Z represents any one of hydrogen, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an aryl group having 6 to 25 carbon atoms. In addition, Ar1 represents an aryl group having 6 to 25 carbon atoms. R1 represents any one of hydrogen, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. Further, M is a central metal and represents an element belonging to Group 9 or Group 10.)
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Page/Page column 59; 60
(2010/11/29)
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- Reaction of 2,3-Diphenylpyrazine 1-Oxides with Acetic Anhydride
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Some 2,3-diphenylpyrazine 1-oxides were heated with acetic anhydride to give the corresponding 2,3-diacetoxy-2,3-dihydro-5,6-diphenylpyrazines.By X-ray diffraction analysis, the configuration of two acetoxyl groups was determined to be trans.
- Ohta, Akihiro,Inoue, Masami,Yamada, Junichi,Yamada, Yasuhiko,Kurihara, Teruo,Honda, Toshihiro
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p. 103 - 106
(2007/10/02)
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