We have synthesized three bis (thienyl) quinoxalinesilver(I) complexes;however, unlike analogous silver(I) complexes of pyridylquinoxaline that utilize (N, N) bidentate behavior from the quinoxaline and pyridyl ring n...We have synthesized three bis (thienyl) quinoxalinesilver(I) complexes;however, unlike analogous silver(I) complexes of pyridylquinoxaline that utilize (N, N) bidentate behavior from the quinoxaline and pyridyl ring nitrogens, the bis(thienyl) quinoxaline ligands did not utilize the bonding potential of the thienyl rings to give (N, S) bonding modes. PES spectra modeling of these ligands indicates that the preferential metal bonding via only the quinoxaline nitrogen atoms is due to the N-rich, but S-poor, characters of the frontier orbitals.展开更多
This work is devoted to the study of the inhibition of corrosion of mild steel(MS)in molar hydrochloric acid(1 mol·L-1 HCl)by two named quinoxaline derivatives namely,2-(2,4-dichlorophenyl)-1,4-dihydroquinoxaline...This work is devoted to the study of the inhibition of corrosion of mild steel(MS)in molar hydrochloric acid(1 mol·L-1 HCl)by two named quinoxaline derivatives namely,2-(2,4-dichlorophenyl)-1,4-dihydroquinoxaline(HQ)and 2-(2,4-dichlorophenyl)-6-methyl-1,4-dihydroquinoxaline(CQ).The inhibitory efficacy of HQ and CQ compounds is first evaluated using the gravimetric method and using electrochemical techniques(stationary and transient techniques).The results showed that our compounds are efficient corrosion inhibitors and the inhibition rates(ηEIS%)reached up to 91%and 94.2%at 10-3 mol·L-1 for HQ and CQ,respectively.The mentioned molecules are classified as mixed-type inhibitors.The adsorption of these inhibitors on the surface of steel in hydrochloric HCl 1 mol·L-1 medium obeys the Langmuir adsorption isotherm.The results of the scanning electron microscope(SEM)showed the formation of a protective film on the surface of the steel in the presence of the inhibitors studied.Elementary analysis is obtained by energy dispersive X-ray spectroscopy(EDS).The inhibition property was further elucidated by theoretical approaches such as:Density Functional Theory(DFT),quantum chemical descriptors(QCD),local reactive indices,solvent effect,theoretical complexation,Molecular Dynamic(MD)simulation,effect of temperature on adsorption energy(Eads),Radial Distribution Function(RDF),and Mean Square Displacement(MSD).The results of these approaches support the experimental results.展开更多
Ga（ClO4）3-catalyzed reaction of 1,2-aryldiamines and α-bromoketones to afford 2-substituted quinoxalines in good yields is described.The reaction proceeded via grinding process with 10%（molar fraction） catalyst u...Ga（ClO4）3-catalyzed reaction of 1,2-aryldiamines and α-bromoketones to afford 2-substituted quinoxalines in good yields is described.The reaction proceeded via grinding process with 10%（molar fraction） catalyst under solvent-free conditions at room temperature.For unsymmetrical o-phenylenediamines bearing electron-withdrawing groups,regio-selective quinoxalines were obtained.展开更多
A facile procedure for the synthesis, of quinoxalines is being reported starting from benzil and 1,2-diaminobenzene. The reactions were carried out catalyst-free, solvent-free and under microwave irradiation condition...A facile procedure for the synthesis, of quinoxalines is being reported starting from benzil and 1,2-diaminobenzene. The reactions were carried out catalyst-free, solvent-free and under microwave irradiation conditions in high yield （84-98%） with short time （3-6 min） and environmental benign, as well as convenient operation. The structures of all the compounds have been confirmed on the basis of their IR, 1H NMR, and/or 13C NMR, mass spectral data.展开更多
A facile and convenient synthesis method has been developed for substituted quinoxalines and 2H-benzo[b][1,4]oxazines from the reactions of a-bromoketones with benzene-1,2-diamine and 2-aminophenol, respectively, whic...A facile and convenient synthesis method has been developed for substituted quinoxalines and 2H-benzo[b][1,4]oxazines from the reactions of a-bromoketones with benzene-1,2-diamine and 2-aminophenol, respectively, which were catalyzed by tetrabutylammonium bromide（TBAB） in aqueous basic media.展开更多
Nano-TiO_2 as an eco-friendly and efficient nanocatalyst was applied for quinoxaline preparation with improved yield.In this protocol,diketones and 1,2-diamines were condensed in the presence of catalyst at room tempe...Nano-TiO_2 as an eco-friendly and efficient nanocatalyst was applied for quinoxaline preparation with improved yield.In this protocol,diketones and 1,2-diamines were condensed in the presence of catalyst at room temperature.展开更多
An interesting and recyclable activated carbon/water catalytic system for efficient synthesis of pyrrolo[1,2-a]quinoxaline derivatives was developed. The intramolecular C-N and C-C bond can be easily constructed in wa...An interesting and recyclable activated carbon/water catalytic system for efficient synthesis of pyrrolo[1,2-a]quinoxaline derivatives was developed. The intramolecular C-N and C-C bond can be easily constructed in water under mild condition. This reaction features a broad substrate scope, a good tolerance to water and air, metal-free, additive-free and redox reagent-free.展开更多
Promoted by CuI/2-hydroxybenzohydrazide catalytic system,a variety of pyrrole-and imidazole-fused quinoxalines have been efficiently one-pot synthesized from pyrrole-/imidazole-2-carboxaldehyde and 2-haloanilines in m...Promoted by CuI/2-hydroxybenzohydrazide catalytic system,a variety of pyrrole-and imidazole-fused quinoxalines have been efficiently one-pot synthesized from pyrrole-/imidazole-2-carboxaldehyde and 2-haloanilines in moderate to excellent yields.展开更多
Two catalysts, alumina and manganese oxide supported on alumina, have been prepared by calcination and precipitation-impregnation methods, respectively. The catalysts are characterised by the following techniques： Br...Two catalysts, alumina and manganese oxide supported on alumina, have been prepared by calcination and precipitation-impregnation methods, respectively. The catalysts are characterised by the following techniques： Brunner-Emmett-Teller-N2 adsorption-desorption for sur- face area, temperature programmed desorption of NH3 and n-butyl amine back titration methods for surface acidity, powder X-ray diffraction for textural properties, and Fourier transform infrared spectroscopy for the anionic radicals. The catalytic activity has been determined under heterogeneous conditions in the condensation reaction between o-phenylenediamine and benzil. The product purity is checked by thin-layer chromatography and melting point. The products are also analysed by LC-MS and 1H-NMR techniques. The yields of the products have been found to be good and catalysts exhibited excellent recyclability. The effect of changing the reaction para- meters such as temperature, reaction time, amount of the catalyst, nature of solvent and molar ratio of reactants on the yield of the product has been studied. The surface acidity of the catalysts plays an important role in activating the reaction.展开更多
A green protocol for the synthesis of quinoxalines has been developed from catalytic oxidative cyclization of deoxybenzoins with 1,2-phenylenediamines in water.The optimal conditions are involved in the use of a water...A green protocol for the synthesis of quinoxalines has been developed from catalytic oxidative cyclization of deoxybenzoins with 1,2-phenylenediamines in water.The optimal conditions are involved in the use of a water-soluble mononuclear copper（Ⅱ） complex of a zwitterionic calix[4]arene[Cu（Ⅱ）LCH2O）]I2（1,H4L=[5,ll,17,23-tetrakis（trimethylammonium）-25,26,27,28-tetrahydroxycalix[4]arene]） as a catalyst in alkali solution after refluxing for 15 h in O2.The target quinoxaline and its derivatives were obtained in good yields（up to 88%）.The procedure described in this paper is simple,practical and environmentally benign.展开更多
Visible light-driven valorization of biomass has recently been a pioneering field for nitrogen-containing heterocyclics syntheses due to its sustainable features.Herein,various aromatic ring-doped g-C_(3)N_(4) nanoshe...Visible light-driven valorization of biomass has recently been a pioneering field for nitrogen-containing heterocyclics syntheses due to its sustainable features.Herein,various aromatic ring-doped g-C_(3)N_(4) nanosheets(Ar-g-C_(3)N_(4);Ar=Py,Pm,Ph)were precisely designed to modulate their intrinsic electronic and band structure,which involves pyridine(Py),pyrimidine(Pm),and benzene(Ph)-doped g-C_(3)N_(4).Photocatalysts(CoPc/Ar-g-C_(3)N_(4)) of cobalt(II)phthalocyanine(CoPc)-fabricated Ar-g-C_(3)N_(4) were then developed for oxidative cyclization of furoin with 1,2-phenylenediamines for syntheses of various biomass-derived quinoxalines under visible-light irradiation.The catalytic activity(in terms of TOFs)of serial CoPc/Ar-g-C_(3)N_(4) samples increased with their transient photocurrents with CoPc/Py-g-C_(3)N_(4) as the most active one.For CoPc/Py-g-C_(3)N_(4),CoPc species functioned as both sensitizer and catalytic sites;while,doped Py led to a narrowed bandgap energy.Mechanism research further demonstrated that O_(2) was activated to superoxide radical(·O_(2)^(-)) by photoexcited high-level-energy electron(HLEE)transfer from Py-g-C_(3)N_(4) to CoPc for the subsequent aerobic oxidation.展开更多
Condensation of D-glucose, o-phenylenediamine and N,N-benzylphenylhydrazine hydrochloride (NNBPHH) in a one-pot reaction, or condensation of 2-(D-arabino-tetritol-1-yl) quinoxaline and NNBPHH, gave 3-(D-erythro-glycer...Condensation of D-glucose, o-phenylenediamine and N,N-benzylphenylhydrazine hydrochloride (NNBPHH) in a one-pot reaction, or condensation of 2-(D-arabino-tetritol-1-yl) quinoxaline and NNBPHH, gave 3-(D-erythro-glycerol-1- yl)-1-phenyl-1H-pyrazolo[3,4-b]quinoxaline. The structure of the latter was determined by 1H NMR spectroscopy and by synthesis using phenylhydrazine hydrochloride instead of NNBPHH. Condensation of D-glucose and 4,5-dichloro-o-phenylenediamine gave 6,7-dichloro-2-(D-arabino-tetritol-1-yl)quinoxaline, which upon condensation with NNBPHH gave the corresponding 6,7-dichloro-3-(D-erythro-glycerol-1-yl)-1-phenyl-1H-pyrazolo[3,4-b]quinoxaline. The structure and mechanism of formation of these compounds are discussed.展开更多
Keggin type heteropolyacids was found to be an efficient and reusable catalyst for the synthesis of biologically active quinoxaline derivatives from the condensation of 1,2-diamine with 1,2-dicarbonyl compounds in exc...Keggin type heteropolyacids was found to be an efficient and reusable catalyst for the synthesis of biologically active quinoxaline derivatives from the condensation of 1,2-diamine with 1,2-dicarbonyl compounds in excellent yields in water. This method provides a new and efficient protocol in terms of small quantity of catalyst, a wide scope of substrates, and simple work-up procedure.展开更多
Polyethylene glycol(PEG) was found to be an effective catalyst for the condensation of 1,2-diamines with 1,2-dicarbonyl compounds to afford the corresponding quinoxaline derivatives in excellent yields under mild reac...Polyethylene glycol(PEG) was found to be an effective catalyst for the condensation of 1,2-diamines with 1,2-dicarbonyl compounds to afford the corresponding quinoxaline derivatives in excellent yields under mild reaction conditions.展开更多
One complex [Co1.5（C6H5CHCHCOO）3（Medpq）]·H2O（C6H5CHCHCOO = cinnamic acid, Medpq = 2-methyldipyrido[3,2-f：2,3-h]quinoxaline） 1 has been hydrothermally synthesized and structurally characterized by elemental...One complex [Co1.5（C6H5CHCHCOO）3（Medpq）]·H2O（C6H5CHCHCOO = cinnamic acid, Medpq = 2-methyldipyrido[3,2-f：2,3-h]quinoxaline） 1 has been hydrothermally synthesized and structurally characterized by elemental analysis, IR spectrum, TG, single-crystal X-ray diffraction and magnetic susceptibility measurements. Complex 1 crystallizes in the triclinic system, space group P1, with a = 10.224（5）, b = 14.572（5）, c = 15.139（5）A, α = 112.704（5）, β = 97.168（5）, γ = 109.749（5）, V = 1871.8（13） 3 and Z = 2（at 293（2） K）. In the crystal structure, the Co（1） ion is hexa-coordinated with six atoms from three different cinnamic acid ligands and the symmetric three different cinnamic acid ligands; the Co（2） center adopts a coordination environment with two nitrogen atoms from Medpq ligand and four oxygen atoms from two different cinnamic ligands, assuming a slightly distorted octahedral geometry, respectively. The negative value of the Weiss constant indicates antiferromagnetic exchange interactions between the Co ions.展开更多
Two unusual one-dimensional（1-D） compounds,viz.[Co（Medpq）（QUI）·H2O]2n· 2.4nH2O 1 and [Cd（Medpq）（QUI）·H2O]n·nH2O 2,were synthesized by the combination of two different metallic salts and o...Two unusual one-dimensional（1-D） compounds,viz.[Co（Medpq）（QUI）·H2O]2n· 2.4nH2O 1 and [Cd（Medpq）（QUI）·H2O]n·nH2O 2,were synthesized by the combination of two different metallic salts and organic ligands,namely 2,3-pyridinedicarboxylic acid（H2QUI） and 2-methyldipyrido[3,2-f：2＇,3＇-h]quinoxaline（Medpq） ligand.The compounds were characterized by elemental analyses,TG,fluorescent emission and single-crystal X-ray diffraction analyses.展开更多
Quinoxaline 1, 4-dioxides (QdNOs) are quinox-aline derivatives which have been used as an-timicrobial agents and growth promoters in animals widely. They are also assumed to cure human disease such as anticancer, anti...Quinoxaline 1, 4-dioxides (QdNOs) are quinox-aline derivatives which have been used as an-timicrobial agents and growth promoters in animals widely. They are also assumed to cure human disease such as anticancer, antitubercular and inhibiting parasite. QdNOs such as carbadox and their major metabolites induced a special decline of aldosterone production from the swine adrenal in vivo and in vitro, and thus cause hypovolemia, hyponatremia and hyperkalemia. This can also be expected to be the case for human. As a mainly physiological hormone and a novel steroid with potent mineralocorticoid activity, aldosterone plays an important role in the pathophysiological process of brain, renal and heart disease progression and may be a renal and vascular risk factor. Here, we provide evidence to support the hypothesis that QdNOs may lead potential benefits in aldosterone dysmetabolism disease via the synthesis deficiency of aldosterone in adrenal and/or the cardiovascular tissues. If the hypothesis is true, it may provide a new option into the therapy for aldosterone dysmetabolism disease, especially in cardiovascular system, and thus assume a broader application of QdNOs.展开更多
The interaction of metal ions（Hg^2＋,Pb^2＋,Co^2＋,Mn^2＋） with polypyridyl quinoxaline ligand 2,3,6,7,10,11-hexakis（2-pyridyl）dipyrazino[2,3-f：20,30-h]quinoxaline（HPDQ） was investigated,and four new complexes ...The interaction of metal ions（Hg^2＋,Pb^2＋,Co^2＋,Mn^2＋） with polypyridyl quinoxaline ligand 2,3,6,7,10,11-hexakis（2-pyridyl）dipyrazino[2,3-f：20,30-h]quinoxaline（HPDQ） was investigated,and four new complexes have been synthesized and characterized.Complex 1 exhibits a 0dimensional dual-core structure,2 is a one-dimensional chain structure based on a dual-core Pb unit,while 3 and 4 show a 0 dimensional single-core structural unit.Complex 1 is of monoclinic system,space group C2/c with a = 19.211（4）,b = 23.896（5）,c = 12.698（3） A°,β= 120.11（3）°,V= 5043.0（17）A°3,Z = 4,S = 1.053,F（000） = 2976,R^a = 0.0637 and wR^b = 0.1068（I 〉 2σ（I））.Complex 2 adopts triclinic system,space group P1 with a = 10.370（2）,b = 12.195（2）,c = 21.033（4） A°,α = 80.87（3）,β= 81.22（3）,γ = 82.38（3）°,V= 2579.3（8） A°3,Z = 2,S = 1.099,F（000） = 1328,R^a = 0.0609 and wR^b =0.1365（I 〉 2σ（I））.Complex 3 is of monoclinic system,space group Cllc with a = 14.166（3）,b =16.621（3）,c = 20.248（4） ？,β = 92.18（3）°,V= 4764.0（16） A°3,Z = 4,S = 1.005,F（000） = 2108,R^a =0.0589 and wR^b = 0.1332（I 〉 2σ（I））.Complex 4 belongs to the monoclinic system,space group C2/c with a = 14.404（3）,b = 16.626（3）,c = 20.346（4） ？,β = 92.43（3）°,V= 4868.2（17） A°3,Z = 4,S= 1.068,F（000） = 2108,R^a = 0.0833 and wR^b = 0.1591（I 〉 2σ（I））.Furthermore,the behavior of HPDQ with Hg^2＋,Pb^2＋,Co^2＋ and Mn^2＋ in the solution was also investigated,and the result shows after the metal ions were added respectively,the emission of all solutions shows fluorescence quenching and has a red shift compared with that of the HPDQ ligand.展开更多
Aromatic/aliphatic polyamides were synthesized from a diamine monomer, 2,3-bis-p-aminophenylquinoxaline （IV）, based on quinoxaline and various dicarboxylic acids of aliphatic, aromatic and heterocyclic. The diamine ...Aromatic/aliphatic polyamides were synthesized from a diamine monomer, 2,3-bis-p-aminophenylquinoxaline （IV）, based on quinoxaline and various dicarboxylic acids of aliphatic, aromatic and heterocyclic. The diamine and polyamides were characterized by elemental analysis, FTIR and IH-NMR. The solubility of the polyamides was affected by the quinoxaline and heterocyclic groups in the polymer chain. They were all soluble in common organic solvents such as dimethylsulfoxide （DMSO）, N,N-dimethylformamide （DMF） and N-methylpyrolidone （NMP）. The polyamides showed inherent viscosity in the range of 0.25-0.3 dL/g in DMSO at 25℃ and good thermal stability with the char yields in the range of 65%-82% at 600℃ in nitrogen.展开更多
The interaction of Hg（Ⅱ）, Cu（Ⅰ） and Ag（Ⅰ） with dipyridine quinoxaline ligand 2,3-bis（2-pyridyl）quinoxaline（DPQ） were investigated, and three new complexes have been synthesized and characterized. Complex ...The interaction of Hg（Ⅱ）, Cu（Ⅰ） and Ag（Ⅰ） with dipyridine quinoxaline ligand 2,3-bis（2-pyridyl）quinoxaline（DPQ） were investigated, and three new complexes have been synthesized and characterized. Complex 1 exhibits a 0D dual-core structure, complex 2 is a 0D tetra nuclear case based on a dual-core Cu unit, and complex 3 shows a one-dimensional pipeline structure. Furthermore, the optical properties of complex and DPQ were also investigated, and the results showed that the fluorescence intensity of complexes was weaker than that of ligand DPQ.展开更多
文摘We have synthesized three bis (thienyl) quinoxalinesilver(I) complexes;however, unlike analogous silver(I) complexes of pyridylquinoxaline that utilize (N, N) bidentate behavior from the quinoxaline and pyridyl ring nitrogens, the bis(thienyl) quinoxaline ligands did not utilize the bonding potential of the thienyl rings to give (N, S) bonding modes. PES spectra modeling of these ligands indicates that the preferential metal bonding via only the quinoxaline nitrogen atoms is due to the N-rich, but S-poor, characters of the frontier orbitals.
文摘This work is devoted to the study of the inhibition of corrosion of mild steel(MS)in molar hydrochloric acid(1 mol·L-1 HCl)by two named quinoxaline derivatives namely,2-(2,4-dichlorophenyl)-1,4-dihydroquinoxaline(HQ)and 2-(2,4-dichlorophenyl)-6-methyl-1,4-dihydroquinoxaline(CQ).The inhibitory efficacy of HQ and CQ compounds is first evaluated using the gravimetric method and using electrochemical techniques(stationary and transient techniques).The results showed that our compounds are efficient corrosion inhibitors and the inhibition rates(ηEIS%)reached up to 91%and 94.2%at 10-3 mol·L-1 for HQ and CQ,respectively.The mentioned molecules are classified as mixed-type inhibitors.The adsorption of these inhibitors on the surface of steel in hydrochloric HCl 1 mol·L-1 medium obeys the Langmuir adsorption isotherm.The results of the scanning electron microscope(SEM)showed the formation of a protective film on the surface of the steel in the presence of the inhibitors studied.Elementary analysis is obtained by energy dispersive X-ray spectroscopy(EDS).The inhibition property was further elucidated by theoretical approaches such as:Density Functional Theory(DFT),quantum chemical descriptors(QCD),local reactive indices,solvent effect,theoretical complexation,Molecular Dynamic(MD)simulation,effect of temperature on adsorption energy(Eads),Radial Distribution Function(RDF),and Mean Square Displacement(MSD).The results of these approaches support the experimental results.
基金Supported by the National Natural Science Foundation of China(Nos.20772088,21172163)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China(No.JSSYSXK2010007)
文摘Ga（ClO4）3-catalyzed reaction of 1,2-aryldiamines and α-bromoketones to afford 2-substituted quinoxalines in good yields is described.The reaction proceeded via grinding process with 10%（molar fraction） catalyst under solvent-free conditions at room temperature.For unsymmetrical o-phenylenediamines bearing electron-withdrawing groups,regio-selective quinoxalines were obtained.
基金Jiangsu Key Laboratory for Chemistry of Low-Dimensional Materials for financial support(No.JSKC07041)
文摘A facile procedure for the synthesis, of quinoxalines is being reported starting from benzil and 1,2-diaminobenzene. The reactions were carried out catalyst-free, solvent-free and under microwave irradiation conditions in high yield （84-98%） with short time （3-6 min） and environmental benign, as well as convenient operation. The structures of all the compounds have been confirmed on the basis of their IR, 1H NMR, and/or 13C NMR, mass spectral data.
基金Supported by the National Natural Science Foundation of China(Nos.20572013 and 20711130229)the Department of Science and Technology of Jilin Province, China(No.20050309-2).
文摘A facile and convenient synthesis method has been developed for substituted quinoxalines and 2H-benzo[b][1,4]oxazines from the reactions of a-bromoketones with benzene-1,2-diamine and 2-aminophenol, respectively, which were catalyzed by tetrabutylammonium bromide（TBAB） in aqueous basic media.
基金Financial support for this work by the Research Council of Yazd University is gratefully acknowledged
文摘Nano-TiO_2 as an eco-friendly and efficient nanocatalyst was applied for quinoxaline preparation with improved yield.In this protocol,diketones and 1,2-diamines were condensed in the presence of catalyst at room temperature.
基金the financial support from the National Natural Science Foundation of China (Nos. 21432009, 21672200, 21472177, 21772185 and 21801233)for the assistance of the product characterization from the Chemistry Experiment Teaching Center of University of Science and Technology of Chinasupported by the Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDB20000000)
文摘An interesting and recyclable activated carbon/water catalytic system for efficient synthesis of pyrrolo[1,2-a]quinoxaline derivatives was developed. The intramolecular C-N and C-C bond can be easily constructed in water under mild condition. This reaction features a broad substrate scope, a good tolerance to water and air, metal-free, additive-free and redox reagent-free.
基金the National Basic Research Program of China(973 Program,No.2012CB722603)the NSFC(Nos.21103114,21463022)and Training Program for Distinguished Youth Scholars of Shihezi University(No.2014ZRKXJQ05)for their financial support.
文摘Promoted by CuI/2-hydroxybenzohydrazide catalytic system,a variety of pyrrole-and imidazole-fused quinoxalines have been efficiently one-pot synthesized from pyrrole-/imidazole-2-carboxaldehyde and 2-haloanilines in moderate to excellent yields.
文摘Two catalysts, alumina and manganese oxide supported on alumina, have been prepared by calcination and precipitation-impregnation methods, respectively. The catalysts are characterised by the following techniques： Brunner-Emmett-Teller-N2 adsorption-desorption for sur- face area, temperature programmed desorption of NH3 and n-butyl amine back titration methods for surface acidity, powder X-ray diffraction for textural properties, and Fourier transform infrared spectroscopy for the anionic radicals. The catalytic activity has been determined under heterogeneous conditions in the condensation reaction between o-phenylenediamine and benzil. The product purity is checked by thin-layer chromatography and melting point. The products are also analysed by LC-MS and 1H-NMR techniques. The yields of the products have been found to be good and catalysts exhibited excellent recyclability. The effect of changing the reaction para- meters such as temperature, reaction time, amount of the catalyst, nature of solvent and molar ratio of reactants on the yield of the product has been studied. The surface acidity of the catalysts plays an important role in activating the reaction.
基金the financial supports from the National Natural Science Foundation of China(Nos.21271134, 21373142,21531006 and 21671144)the State Key Laboratory of Organometallic Chemistry,Shanghai Institute of Organic Chemistry(No.2015kf-07)+2 种基金supports from the "333" Project of Jiangsu Provincethe Priority Academic Program Development of Jiangsu Higher Education Institutionsthe "SooChow Scholar" Program of Soochow University
文摘A green protocol for the synthesis of quinoxalines has been developed from catalytic oxidative cyclization of deoxybenzoins with 1,2-phenylenediamines in water.The optimal conditions are involved in the use of a water-soluble mononuclear copper（Ⅱ） complex of a zwitterionic calix[4]arene[Cu（Ⅱ）LCH2O）]I2（1,H4L=[5,ll,17,23-tetrakis（trimethylammonium）-25,26,27,28-tetrahydroxycalix[4]arene]） as a catalyst in alkali solution after refluxing for 15 h in O2.The target quinoxaline and its derivatives were obtained in good yields（up to 88%）.The procedure described in this paper is simple,practical and environmentally benign.
基金supported by the National Natural Science Foundation of China(22075104)the Youth Science and Technology Innovation Talent of Guangdong TeZhi Plan,China(2019TQ05L111)+1 种基金Innovation Team Project in Guangdong Colleges and Universities,China(2021KCXTD009)Educational Commission of Guangdong Province of China(2021ZDZX4037)。
文摘Visible light-driven valorization of biomass has recently been a pioneering field for nitrogen-containing heterocyclics syntheses due to its sustainable features.Herein,various aromatic ring-doped g-C_(3)N_(4) nanosheets(Ar-g-C_(3)N_(4);Ar=Py,Pm,Ph)were precisely designed to modulate their intrinsic electronic and band structure,which involves pyridine(Py),pyrimidine(Pm),and benzene(Ph)-doped g-C_(3)N_(4).Photocatalysts(CoPc/Ar-g-C_(3)N_(4)) of cobalt(II)phthalocyanine(CoPc)-fabricated Ar-g-C_(3)N_(4) were then developed for oxidative cyclization of furoin with 1,2-phenylenediamines for syntheses of various biomass-derived quinoxalines under visible-light irradiation.The catalytic activity(in terms of TOFs)of serial CoPc/Ar-g-C_(3)N_(4) samples increased with their transient photocurrents with CoPc/Py-g-C_(3)N_(4) as the most active one.For CoPc/Py-g-C_(3)N_(4),CoPc species functioned as both sensitizer and catalytic sites;while,doped Py led to a narrowed bandgap energy.Mechanism research further demonstrated that O_(2) was activated to superoxide radical(·O_(2)^(-)) by photoexcited high-level-energy electron(HLEE)transfer from Py-g-C_(3)N_(4) to CoPc for the subsequent aerobic oxidation.
文摘Condensation of D-glucose, o-phenylenediamine and N,N-benzylphenylhydrazine hydrochloride (NNBPHH) in a one-pot reaction, or condensation of 2-(D-arabino-tetritol-1-yl) quinoxaline and NNBPHH, gave 3-(D-erythro-glycerol-1- yl)-1-phenyl-1H-pyrazolo[3,4-b]quinoxaline. The structure of the latter was determined by 1H NMR spectroscopy and by synthesis using phenylhydrazine hydrochloride instead of NNBPHH. Condensation of D-glucose and 4,5-dichloro-o-phenylenediamine gave 6,7-dichloro-2-(D-arabino-tetritol-1-yl)quinoxaline, which upon condensation with NNBPHH gave the corresponding 6,7-dichloro-3-(D-erythro-glycerol-1-yl)-1-phenyl-1H-pyrazolo[3,4-b]quinoxaline. The structure and mechanism of formation of these compounds are discussed.
文摘Keggin type heteropolyacids was found to be an efficient and reusable catalyst for the synthesis of biologically active quinoxaline derivatives from the condensation of 1,2-diamine with 1,2-dicarbonyl compounds in excellent yields in water. This method provides a new and efficient protocol in terms of small quantity of catalyst, a wide scope of substrates, and simple work-up procedure.
基金supported by the Natural Science Foundation of China(No.20272047,20572086)the Gansu Natural Science Foundation of China(No.0308RJZA-100)Key Laboratory of Eco-Environment-Related Polymer Material(Northwest Normal University),Ministry of the Education of China
文摘Polyethylene glycol(PEG) was found to be an effective catalyst for the condensation of 1,2-diamines with 1,2-dicarbonyl compounds to afford the corresponding quinoxaline derivatives in excellent yields under mild reaction conditions.
基金supported by Tonghua Normal University field project(No.201402)
文摘One complex [Co1.5（C6H5CHCHCOO）3（Medpq）]·H2O（C6H5CHCHCOO = cinnamic acid, Medpq = 2-methyldipyrido[3,2-f：2,3-h]quinoxaline） 1 has been hydrothermally synthesized and structurally characterized by elemental analysis, IR spectrum, TG, single-crystal X-ray diffraction and magnetic susceptibility measurements. Complex 1 crystallizes in the triclinic system, space group P1, with a = 10.224（5）, b = 14.572（5）, c = 15.139（5）A, α = 112.704（5）, β = 97.168（5）, γ = 109.749（5）, V = 1871.8（13） 3 and Z = 2（at 293（2） K）. In the crystal structure, the Co（1） ion is hexa-coordinated with six atoms from three different cinnamic acid ligands and the symmetric three different cinnamic acid ligands; the Co（2） center adopts a coordination environment with two nitrogen atoms from Medpq ligand and four oxygen atoms from two different cinnamic ligands, assuming a slightly distorted octahedral geometry, respectively. The negative value of the Weiss constant indicates antiferromagnetic exchange interactions between the Co ions.
文摘Two unusual one-dimensional（1-D） compounds,viz.[Co（Medpq）（QUI）·H2O]2n· 2.4nH2O 1 and [Cd（Medpq）（QUI）·H2O]n·nH2O 2,were synthesized by the combination of two different metallic salts and organic ligands,namely 2,3-pyridinedicarboxylic acid（H2QUI） and 2-methyldipyrido[3,2-f：2＇,3＇-h]quinoxaline（Medpq） ligand.The compounds were characterized by elemental analyses,TG,fluorescent emission and single-crystal X-ray diffraction analyses.
文摘Quinoxaline 1, 4-dioxides (QdNOs) are quinox-aline derivatives which have been used as an-timicrobial agents and growth promoters in animals widely. They are also assumed to cure human disease such as anticancer, antitubercular and inhibiting parasite. QdNOs such as carbadox and their major metabolites induced a special decline of aldosterone production from the swine adrenal in vivo and in vitro, and thus cause hypovolemia, hyponatremia and hyperkalemia. This can also be expected to be the case for human. As a mainly physiological hormone and a novel steroid with potent mineralocorticoid activity, aldosterone plays an important role in the pathophysiological process of brain, renal and heart disease progression and may be a renal and vascular risk factor. Here, we provide evidence to support the hypothesis that QdNOs may lead potential benefits in aldosterone dysmetabolism disease via the synthesis deficiency of aldosterone in adrenal and/or the cardiovascular tissues. If the hypothesis is true, it may provide a new option into the therapy for aldosterone dysmetabolism disease, especially in cardiovascular system, and thus assume a broader application of QdNOs.
基金supported by the NNSFC(21301100)the Education Department Fund of Henan(13A150819)Special fund of Nanyang Normal University(ZX2013029)
文摘The interaction of metal ions（Hg^2＋,Pb^2＋,Co^2＋,Mn^2＋） with polypyridyl quinoxaline ligand 2,3,6,7,10,11-hexakis（2-pyridyl）dipyrazino[2,3-f：20,30-h]quinoxaline（HPDQ） was investigated,and four new complexes have been synthesized and characterized.Complex 1 exhibits a 0dimensional dual-core structure,2 is a one-dimensional chain structure based on a dual-core Pb unit,while 3 and 4 show a 0 dimensional single-core structural unit.Complex 1 is of monoclinic system,space group C2/c with a = 19.211（4）,b = 23.896（5）,c = 12.698（3） A°,β= 120.11（3）°,V= 5043.0（17）A°3,Z = 4,S = 1.053,F（000） = 2976,R^a = 0.0637 and wR^b = 0.1068（I 〉 2σ（I））.Complex 2 adopts triclinic system,space group P1 with a = 10.370（2）,b = 12.195（2）,c = 21.033（4） A°,α = 80.87（3）,β= 81.22（3）,γ = 82.38（3）°,V= 2579.3（8） A°3,Z = 2,S = 1.099,F（000） = 1328,R^a = 0.0609 and wR^b =0.1365（I 〉 2σ（I））.Complex 3 is of monoclinic system,space group Cllc with a = 14.166（3）,b =16.621（3）,c = 20.248（4） ？,β = 92.18（3）°,V= 4764.0（16） A°3,Z = 4,S = 1.005,F（000） = 2108,R^a =0.0589 and wR^b = 0.1332（I 〉 2σ（I））.Complex 4 belongs to the monoclinic system,space group C2/c with a = 14.404（3）,b = 16.626（3）,c = 20.346（4） ？,β = 92.43（3）°,V= 4868.2（17） A°3,Z = 4,S= 1.068,F（000） = 2108,R^a = 0.0833 and wR^b = 0.1591（I 〉 2σ（I））.Furthermore,the behavior of HPDQ with Hg^2＋,Pb^2＋,Co^2＋ and Mn^2＋ in the solution was also investigated,and the result shows after the metal ions were added respectively,the emission of all solutions shows fluorescence quenching and has a red shift compared with that of the HPDQ ligand.
文摘Aromatic/aliphatic polyamides were synthesized from a diamine monomer, 2,3-bis-p-aminophenylquinoxaline （IV）, based on quinoxaline and various dicarboxylic acids of aliphatic, aromatic and heterocyclic. The diamine and polyamides were characterized by elemental analysis, FTIR and IH-NMR. The solubility of the polyamides was affected by the quinoxaline and heterocyclic groups in the polymer chain. They were all soluble in common organic solvents such as dimethylsulfoxide （DMSO）, N,N-dimethylformamide （DMF） and N-methylpyrolidone （NMP）. The polyamides showed inherent viscosity in the range of 0.25-0.3 dL/g in DMSO at 25℃ and good thermal stability with the char yields in the range of 65%-82% at 600℃ in nitrogen.
基金supported by the NSFC(21301100)the Education Department Fund of Henan(13A150819)Special fund of Nanyang Normal University(ZX2013029)
文摘The interaction of Hg（Ⅱ）, Cu（Ⅰ） and Ag（Ⅰ） with dipyridine quinoxaline ligand 2,3-bis（2-pyridyl）quinoxaline（DPQ） were investigated, and three new complexes have been synthesized and characterized. Complex 1 exhibits a 0D dual-core structure, complex 2 is a 0D tetra nuclear case based on a dual-core Cu unit, and complex 3 shows a one-dimensional pipeline structure. Furthermore, the optical properties of complex and DPQ were also investigated, and the results showed that the fluorescence intensity of complexes was weaker than that of ligand DPQ.
