- 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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- Pyrazine phosphorescent iridium complex, preparation method and application thereof
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The invention discloses a pyrazine phosphorescent iridium complex, a preparation method and an application thereof. The iridium complex is represented as the following chemical structure formula, wherein R1 is a C1-C6 alkyl group; and R2, R3, R4, R5, R6 a
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Paragraph 0027
(2016/11/07)
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- Iodine-mediated oxidative annulation for one-pot synthesis of pyrazines and quinoxalines using a multipathway coupled domino strategy
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An efficient iodine-mediated oxidative annulation of aryl acetylenes-arylethenes-aromatic ketones with 1,2-diamines for the synthesis of pyrazines and regioselective synthesis of quinoxalines is presented. A multipathway coupled domino approach has been developed for the one-pot synthesis of 1,4-diazines with high functional group compatibility.
- Viswanadham, K. K. Durga Rao,Prathap Reddy, Muktapuram,Sathyanarayana, Pochampalli,Ravi, Owk,Kant, Ruchir,Bathula, Surendar Reddy
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p. 13517 - 13520
(2015/01/09)
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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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- Synthesis of tetrasubstituted pyrazines and pyrazine N-oxides
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An efficient synthesis of tetrasubstituted unsymmetrical pyrazines and their related pyrazine N-oxides has been developed from commercially available 2-chloro-3-methylpyrazine. The procedure and scope of these synthesis routes are described.
- Jeong, Jae Uk,Dong, Xiaoyang,Rahman, Attiq,Marquis, Robert W.
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scheme or table
p. 974 - 976
(2010/05/03)
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- Latent enamine functionality of 5-methyl-2,3-dihydropyrazines
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Tautomerization of methyl-substituted dihydropyrazine (DHP) derivatives to their latent enamine form was investigated theoretically and empirically. Among two types of hydrogen transfer model simulated by means of density functional theory calculation, a
- Ito, Shigeru,Hirano, Tomoya,Sugimoto, Akiko,Kagechika, Hiroyuki,Takechi, Shinji,Yamaguchi, Tadatoshi
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experimental part
p. 922 - 927
(2010/08/20)
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- Highly efficient phosphorescent iridium (III) diazine complexes for OLEDs: Different photophysical property between iridium (III) pyrazine complex and iridium (III) pyrimidine complex
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The synthesis and luminescence of four new iridium (III) diazine complexes (1-4) were investigated. HOMO and LUMO energy levels of the complexes were estimated according to the electrochemical performance and the UV-Vis absorption spectra, showing the pyr
- Ge, Guoping,He, Jing,Guo, Haiqing,Wang, Fuzhi,Zou, Dechun
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experimental part
p. 3050 - 3057
(2009/12/08)
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- ORGANOMETALLIC COMPLEX AND LIGHT-EMITTING ELEMENT, LIGHT-EMITTING DEVICE AND ELECTRONIC DEVICE USING THE SAME
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An organometallic complex having a structure represented by the general formula (G1) is synthesized and applied to a light-emitting element. In the formula, R1 represents either an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carb
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Page/Page column 73-74
(2010/11/27)
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- Action du phenyllithium en serie pyrazine: Piegeage des intermediaires reactionnels par le benzoate de methyle
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The action of phenyllithium on pyrazine, 2-methyl pyrazine and acetonyl pyrazine gave mono- or di-addition products with azomethines bonds of pyrazine.The adducts can be condensed with methyl benzoate to give C or N condensed derivatives.No product with initial metalation of methyl or acetonyl groups was observed.
- Mettey, Yvette,Vierfond, Jean-Michel
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p. 1051 - 1054
(2007/10/02)
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- Syntheses and Reactions of Some 2,3-Disubstituted Pyrazine Monoxides
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The reactions of 2,3-dimethyl- (4), 2,3-diphenyl- (6), and 2-methyl-3-phenyl-pyrazine monoxides (8 and 9) with phosphoryl chloride and acetic anhydride resulted in giving monochloro- and monoacetoxy-pyrazines in almost all cases.However, the reaction of 6 with acetic anhydride afforded exceptionally a diacetoxydihydropyrazine.These products were converted further to hydroxy or dichloro derivatives.
- Watahiki, Hiroko,Tsutsui, Mayumi,Akita, Yasuo,Watanabe, Tokuhiro,Kurihara, Teruo
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p. 465 - 473
(2007/10/02)
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- Ueber die Synthese von 2,3-Dialkylpyrazinen
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2,3-Dialkylquinoxalines (4), which are available from the reaction of benzofuroxan (1) with ketones and subsequent reduction of the 2,3-dialkylquinoxaline N,N'-dioxides (3), are converted to 2,3-dialkylpyrazines (6) by oxidation-decarboxylation steps.
- Heyns, Kurt,Behse, Ernst,Francke, Wittko
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p. 240 - 245
(2007/10/02)
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- Reactions of organolithium-diazine adducts and dihydrodiazines with electrophilic reagents
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Some organolithium-diazine adducts and some dihydropyrimidines were treated with electrophilic reagents.Both 4,6-diphenyl-1(3)-lithio-1,4(3,4)-dihydropyrimidine and 4,6-diphenyl-1,4(3,4)-dihydropyrimidine were attacked by the electrophilic reagent methyl
- Stoel, R. E. van der,Plas, H. C. van der,Jongejan, H.,Hoeve, L.
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p. 234 - 238
(2007/10/02)
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