1489-06-1Relevant articles and documents
Star-shaped Keggin-type heteropolytungstate nanostructure as a new catalyst for the preparation of quinoxaline derivatives
Masteri-Farahani, Majid,Ghorbani, Melika,Ezabadi, Ali,Farrokhinia, Niki,Ghaemmaghami, Atekeh-Sadat
, p. 1136 - 1143 (2014)
In this work, we report the novel successful preparation of the Keggin-type Cs(CTA)2PW12O40 (CTA = cetyltrimethylammonium cation) nanostructure by a microemulsion method. The microemulsion system included the cationic surfactant CTAB, 1-butanol as co-surfactant, isooctane as oil phase, and an aqueous solution containing CsNO3. The Cs(CTA)2PW12O40 nanostructure was formed by the addition of an aqueous solution of phosphotungstic acid to the microemulsion solution. Characterization of the resultant nanostructure was done using FT-IR spectroscopy, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis, and CHN elemental analysis. The product was found to be a star-shaped nanostructure composed of some nanorods whose diameter and length are about 100 nm and 500 nm, respectively. The prepared nanostructure was used as a recoverable catalyst for the synthesis of quinoxaline derivatives by the condensation of 1,2-diamines with 1,2-dicarbonyl compounds, which afforded the products in good to high yields in short reaction times.
Synthesis of a polymer-capped palladium nanoparticles and its application as a reusable catalyst in oxidative coupling reaction of α-hydroxyketones and 1,2-diamines for preparation of pyrazines and quinoxalines
Zarchi, Mohammad Ali Karimi,Abadi, Seyed Shahab Addin Darbandizadeh Mohammad
, p. 915 - 929 (2018)
A novel method for the synthesis of pyrazines and quinoxalines has been developed using α-hydroxyketones and 1,2-diamines in the presence of cross-linked poly(4-vinylpyridine)-stabilized Pd(0) nanoparticles, [P4-VP]-PdNPs. The catalyst was easily prepared and characterized using various techniques such as FT-IR and UV–Vis spectroscopy, AAS, TEM, FESEM, EDX analysis and XRD. The results confirm a good dispersion of palladium nanoparticles on the polymer support. The catalyst displayed good catalytic activity when applied to the synthesis of quinoxalines via condensation of α-hydroxyketones with 1,2-diamines. A few pyrazine derivatives and various quinoxalines are prepared via coupling reaction of α-hydroxyketones and 1,2-diamines in high–excellent yields (81–99%) with short reaction times. The quinoxalines products were characterized by FT-IR, 1H and 13C NMR spectroscopy, and the physical properties were compared to the literature values of known compounds. The advantages of the present method over conventional classical methods are rapid and very simple work-up, and the catalyst is reusable many times without a significant loss in its activity.
Iodine-mediated efficient synthesis of 2,3-dihydro-pyrazines
Dong, Yansheng,Huang, Li,Yi, Fengping
, p. 430 - 432 (2015)
The synthesis of 2,3-dihydro-pyrazines has been developed by an efficient protocol of annulations of 1,2-diketones and ethylenediamine. A variety of 2,3-dihydro-pyrazines were prepared in high yields in the presence of a catalytic amount of iodine.
An Improved Synthesis of Multi-Substituted Pyrazines under Catalyst- and Solvent-Free Conditions
Tamaddon, Fatemeh,Tafti, Arefeh Dehghani,Pooramini, Farzaneh
, p. 4295 - 4299 (2016)
A one-pot pseudo four-component reaction between a variety of 2-hydroxy-1,2-diarylethanone derivatives and ammonium acetate or amines has been developed to synthesize substituted pyrazines under catalyst-free and solvent-free conditions. This procedure provides a synthetic method to access pyrazine derivatives in excellent yields under green conditions.
Design and construction of copper(I) complexes based on flexi-dentate cyclic N2-donor Schiff bases via in situ reduction of copper(II) precursors
Jana, Subrata,Chattopadhyay, Shouvik
, p. 298 - 307 (2014)
Three copper(I) complexes [Cu(μ2-L1)I]n (1), [CuL1(μ-1,1,3-SeCN)]n (2) and [Cu 2(μ2-I)2(L2)2] (3), where L1 = 5,6-diphenyl-2,3-dihydro
Synthesis, structures, and DFT study of CuBr based coordination polymers via in situ reduction of copper(II)
Jana, Subrata,Harms, Klaus,Bauz??, Antonio,Frontera, Antonio,Chattopadhyay, Shouvik
, p. 257 - 267 (2015)
This paper describes the one-pot synthesis of two CuBr based coordination polymers, {[Cu(??2-L1)Br]?·1.87H2O}n (1) and {[Cu(??2-L2)Br]?·C4H10O}n (2), where
Preparation and Application of α-Imino Ketones through One-Pot Tandem Reactions Based on Heyns Rearrangement
Li, Ling,Zhang, Shiqi,Deng, Xiongfei,Li, Guangxun,Tang, Zhuo,Zhao, Gang
supporting information, p. 6819 - 6824 (2021/09/08)
α-Imino ketone is a useful building block for the preparation of α-amino ketones and α-amino alcohols. However, its preparation has been seldomly seen. Herein, a metal-free and operationally simple strategy has been developed to generate α-imino ketones with high regioselectivity. Meanwhile, the method allowed for the preparation of various N,O-ketals with high regioselectivities and diastereoselectivities through cascade reactions in one pot.
Dowex 50W: Mild efficient reusable heterogeneous catalyst for synthesis of quinoxaline derivatives in aqueous medium
Datta, Arup,Halder, Samiran
, p. 1218 - 1224 (2021/02/09)
An efficient, simple and eco-friendly procedure is reported in presence of heterogeneous Dowex 50W catalyst in aqueous medium under refluxing condition to produce quinoxaline derivatives. Catalyst has participated in condensation reaction between 1,2-diamines and various aromatic 1,2-diketones smoothly with excellent yield of the products in short reaction times. Dowex 50W was used more than five times in this reaction separately and showed an excellent recyclability throughout the reaction.(figure presented).
Porous carbons-derived from vegetal biomass in the synthesis of quinoxalines. Mechanistic insights
Godino-Ojer,Blazquez-García,Matos,Bernardo,Fonseca,Pérez Mayoral
, p. 90 - 99 (2019/06/24)
We report herein for the first-time acid biomass-derived carbons from vegetal biomass, with high developed porosity, prepared through integrating method comprising pyrolysis and surface phosphonation, able to efficiently catalyze the synthesis of quinoxalines from 1,2-diamines and α-hydroxi ketones, under aerobic conditions. The obtained results indicate that the reaction is mainly driven by a combination of acid function strength and textural properties in terms of conversion and selectivity. Furthermore, our experimental and theoretical observations suggest that the preferred reaction pathway for this transformation, in the presence of the investigated acid carbon catalysts, involves cascade reactions including imination reaction between reactants, successive imine-enamine and keto-enol tautomerisms, heterocyclization followed by dehydration, and aromatization. While the acid sites seem to be a relevant role in each reaction step, the system formed by activated carbon and molecular oxygen could be behind the last oxidative reaction to give the corresponding nitrogen heterocycles.
