- Subphthalocyanine azaanalogues – Boron(III) subporphyrazines with fused pyrazine fragments
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Сyclotrimerization of pyrazine-2,3-dicarbonitrile and its phenyl substituted derivative in the presence of BCl3 in p-xylene leads to azaanalogues of subphthalocyanine dye. Non-substituted tripyrazinosubporphyrazine [Pyz3sPABCl] was formed only in trace amounts allowing only limited spectral study in solution. Hexaphenyl substituted derivative [Ph6Pyz3sPABCl] was isolated as chlorboron(III) complex and fully characterized by 1H, 13C, 11B NMR, IR, electronic absorption and emission spectroscopy, cyclovoltammetry and its structure was established by single crystal X-ray diffraction. Pyrazine fused subporphyrazines exhibit strong absorption bands at 300–310 and 530–550 nm. The phenyl substituted derivative [Ph6Pyz3sPABCl] has an additional intense charge transfer band at 390 nm and can be reversibly reduced at ?0.81 V (vs Ag/AgCl in MeCN). The influence of pyrazine rings on the geometrical and electronic structural features and spectral properties of subporphyrazine dye was also studied using DFT and TD DFT methods. Experimental and theoretical results evidence that fusion of pyrazine rings leads to stabilization of the frontier π-molecular orbitals and endows the macrocycle with enhanced electron deficiency. Pyrazine fused subporphyrazines can be considered as perspective dyes intensively absorbing in the 300–600 nm range for applications as n-type materials in organic electronics.
- Stuzhin, Pavel A.,Skvortsov, Ivan A.,Zhabanov, Yuriy A.,Somov, Nikolai V.,Razgonyaev, Oleg V.,Nikitin, Ivan A.,Koifman, Oskar I.
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p. 888 - 897
(2018/11/25)
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- Ionic liquid functionalized cellulose as an efficient heterogeneous catalyst for the facile and green synthesis of benzoxazine, pyrazine and quinoxaline derivatives in aqueous media
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Immobilization of acidic ionic liquid, 1-methyl-3-(3-trimethoxysilylpropyl) imidazolium hydrogen sulfate on cellulose (Cell-[pmim]HSO4) as an efficient heterogenous catalyst for the simple and environmentally benign synthesis of benzoxazine, pyrazine and quinoxaline derivatives in aqueous media at room temperature is described. The catalyst was characterized by FTIR spectroscopy and X-ray diffraction pattern. This method provides several advantages such as mild reaction conditions, environmentally friendly catalyst, good to excellent yields and simple work-up procedure.
- Moghaddam, Sevil Vaghefi,Valizadeh, Hassan
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p. 1517 - 1524
(2016/07/06)
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- Efficient solvent-free synthesis of pyridopyrazine and quinoxaline derivatives using copper-DiAmSar complex anchored on SBA-15 as a reusable catalyst
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A catalytic system comprising mesoporous silica functionalized with Cu(II)-DiAmSar was synthesized. This was demonstrated as an efficient heterogeneous catalyst for the synthesis of biologically useful pyridopyrazine and quinoxaline heterocycles under solvent-free conditions. X-ray diffraction, transmission electron microscopy, N2 adsorption-desorption, Fourtier transformation infrared spectroscopy, and thermogravimetric analysis were used to characterize the catalyst and investigate the texture of SBA-15 during the grafting process.
- Mohammadi, Marzieh,Bardajee, Ghasem Rezanejade,Pesyan, Nader Noroozi
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p. 1379 - 1386
(2015/09/01)
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- An iron Schiff base complex loaded mesoporous silica nanoreactor as a catalyst for the synthesis of pyrazine-based heterocycles
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An iron Schiff base complex was encapsulated in SBA-15 mesoporous silica to afford a Fe(III)-Schiff base/SBA-15 heterogeneous nanocatalyst for the synthesis of pyridopyrazine and quinoxaline heterocycles. These reactions proceeded in water with excellent yields. The catalyst was characterized by physico-chemical and spectroscopic methods and found to retain the characteristic channel structures of the SBA-15, allowing good accessibility of the encapsulated metal complex.
- Malakooti, Reihaneh,Bardajee, Ghasem Rezanejade,Hadizadeh, Somayyeh,Atashin, Hassan,Khanjari, Hadiseh
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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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- ZrOCl2.8H2O in water: An efficient catalyst for rapid one-pot synthesis of pyridopyrazines, pyrazines and 2,3-disubstituted quinoxalines
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Zirconium(IV) oxide chloride was found to be a rapid and efficient catalyst for the synthesis of pyrazines and 2,3-disubstituted quinoxalines in water. A variety of pyridopyrazine and 2,3-disubstituted quinoxaline derivatives are readily prepared in high yields under green conditions by cyclocondensation of the desired 1,2-diamine and 1,2-diketone using a catalytic amount of zirconium(IV) oxide chloride in water. Less active diamines, such as 2,3- and 3,4-diaminopyridines took part in this protocol to provide the desired products in good to excellent yields.
- Bardajee, Ghasem Rezanejade
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p. 872 - 877
(2013/10/22)
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- Zirconium schiff-base complex modified mesoporous silica as an efficient catalyst for the synthesis of nitrogen containing pyrazine based heterocycles
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Zirconium Schiff-base complex modified SBA-15 was synthesized and characterized by powder X-ray diffraction (XRD), BET nitrogen adsorption-desorption methods, IR spectroscopy and thermogravimetric analysis. The XRD and BET analyses show that textural properties of SBA-15 were retained during the grafting procedure. The modified SBA was successfully applied as a heterogeneous catalyst for the synthesis of a library of nitrogen containing pyrazine based heterocycles in good to excellent yields in water media.
- Malakooti, Reihaneh,Bardajee, Ghasem Rezanejade,Mahmoudi, Hesamaldin,Kakavand, Nahale
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p. 853 - 861
(2013/08/23)
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- Covalent anchoring of copper-Schiff base complex into SBA-15 as a heterogeneous catalyst for the synthesis of pyridopyrazine and quinoxaline derivatives
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The ordered mesoporous silica SBA-15 was covalently anchored with copper (II) Schiff base complex to afford Cu(II)-Schiff base/SBA-15 catalyst. Powder X-ray diffraction, nitrogen adsorption-desorption analyses and TEM image confirm not only the retaining of support properties after anchoring but also the existence of void space in nanometer scale which result in good catalytic activity in the synthesis of pyridopyrazine and quinoxaline derivatives.
- Bardajee, Ghasem Rezanejade,Malakooti, Reihaneh,Jami, Fereshteh,Parsaei, Zeinab,Atashin, Hassan
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- Green and efficient synthesis of quinoxaline derivatives via ceric ammonium nitrate promoted and in situ aerobic oxidation of α-hydroxy ketones and α-keto oximes in aqueous media
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The direct conversion of α-hydroxy ketones and α-keto oximes into quinoxaline derivatives in the presence of a catalytic amount of ceric ammonium nitrate via metal-catalyzed aerobic oxidation followed by in situ trapping with aromatic 1,2-diamines in water as a green and efficient reaction media, is reported.
- Shaabani, Ahmad,Maleki, Ali
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