- One-pot new synthetic method for 3-amino-2-quinoxalinecarbonitrile
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A new method for the preparation of 3-amino-2-quinoxalinecarbonitrile (1) was studied. A successful condensation reaction between bromomalononitrile and o-phenylenediamine in the presence of Lewis acid catalyst (AlCl3) was achieved to produce compound 1.
- Waly, Mohamed Attia,El-Gogary, Sameh Ramadan,El-Sepelgy, Osama Zakaria
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- Facile synthesis of hydrazine derivatives of 5H-pyrrolo[3,4-b]pyrazine and 1H-pyrrolo[3,4-b]quinoxaline
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A convenient and efficient route for the chemoselective synthesis of carbohydrazide, arenesulfonylhydrazide, and thiosemicarbazone derivatives of 5H-pyrrolo[3,4-b]pyrazine and 1H-pyrrolo[3,4-b]quinoxaline from the corresponding dinitriles and substituted hydrazines was elaborated. The synthesis of starting pyrazine-2,3-dicarbonitrile was sufficiently improved by using concentrated HCl as a catalyst. Georg Thieme Verlag Stuttgart . New York.
- Hordiyenko, Olga V.,Rudenko, Igor V.,Zamkova, Irina A.,Denisenko, Oleksandr V.,Biitseva, Angelina V.,Arrault, Axelle,Tolmachev, Andrei A.
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p. 3375 - 3382
(2014/01/06)
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- Heterocyclic Colorants Based on Diazabenzoisoindoles
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The invention is directed to novel colorants of formula (I), wherein A represents a group of general formulas (II), (III), (IV) or (V), and B represents a substituted or unsubstituted ortho-C6-C18 arylene, wherein C and D represent an alicyclic or heteroyclic group.
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- 3-Amino-2-quinoxalinecarbonitrile. New fused quinoxalines with potential cytotoxic activity
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Starting with 3-amino-2-quinoxalinecarbonitrile 1,4-dioxide 1, a new series of quinoxaline derivatives was prepared through chemical modifications of the 2-cyano and 3-amino groups. Nitration of 3-amino-2-quinoxalinecarbonitrile 3 afforded the 7-nitro derivative 6. Diazotation of 3 gave the 3-chloro compound 9. 2,3-Quinoxalinedicarbonitrile 14 was obtained from 9. Pyridazino[4,5-b]quinoxalines 15 and 16 were prepared by condensing 14 with hydrazine hydrate. A triazolo[4,5-b]quinoxaline 18, a isothiazolo[4,5-b]quinoxaline 20 and two pyrazolo[3,4-b]quinoxalines 21 and 22 were identified. Compounds were tested as cytotoxic agents both in oxic and in hypoxic cells.
- Monge,Palop,Pinol,Martinez-Crespo,Narro,Gonzalez,Sainz,Lopez De Cerain,Hamilton,Barker
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p. 1135 - 1139
(2007/10/02)
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- Photoelectrochemical Investigations of Naphthalocyanine Derivatives in Thin Films
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Photoelectrochemical properties of Zn-naphthalocyanine (ZnNc) and its modified compounds, Zn-2,3-tetraquinoxalinotetraazaporphyrin (ZnTQP) were investigated in thin films.The ZnNc electrode vacuum-deposited on an indium tin oxide (ITO) substrate exhibited almost an ohmic I-V curve in the dark and small cathodic photocurrents under illumination, which was typical for the p-type semiconduction of the ZnNc layer, in a photoelectrochemical cell.The drop-casted film electrode of ZnTQP, on the other hand, showed rectified I-V characteristics in the dark and high anodic photocurrents under illumination, which was attributed to the n-type semiconducting character of the ZnTQP layer.These different photoelectrochemical behaviors were characterized by photocurrent action spectra and ultraviolet photoelectron spectroscopy.The substitution with quinoxaline groups into the Nc macrocyclic system gave rise to lowering of the HOMO energy level for the TQP molecule.This electronic energy shift generated donor electron states in the band gap after contact with the substrate or electrolyte and enabled the photooxidation at the valence band edges corresponding to the Soret- and Q-band excitations.The pH dependence of the anodic photocurrents for the ZnTQP electrode indicated that the photooxidation occured through a hole injection from the HOMO and underlying sub-HOMO states, separately, for the Soret- and Q-band excitations.For the ZnNc electrode, the Q-band illumination produced cathodic photocurrents, whereas the Soret band produced anodic photocurrents.It suggested that under the Soret-band excitation holes generated in the sub-HOMO state directly contributed to the photooxidation.
- Yanagi, Hisao,Kanbayashi, Yoshihiro,Schlettwein, Derck,Woehrle, Dieter,Amstrong, Neal R.
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p. 4760 - 4766
(2007/10/02)
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- Quinoxalines. XXVII. The cyanation of 2-substituted quinoxaline 4-oxides with trimethylsilyl cyanide
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The deoxy-cyanation of 2-substituted quinoxaline 4-oxides (1a--k) with trimethylsilyl cyanide in the presence of 1,8-diazabicyclo[5.4.0.]undec-7-ene gave the corresponding 3-substituted 2-quinoxalinecarbonitriles (IIa--k). However, in the case of 2-(p-tol
- Iijima,Miyashita
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p. 661 - 663
(2007/10/02)
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- Synthesis of Cyano-Substituted Heterocycles by Means of Tetraethylammonium Cyanide
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Chloropyrimidines 2, 3 and Chlorquinazolines 9, 10, after conversion into trimethylammonio derivatives 4, 5, 11, 12, react with tetraethylammonium cyanide 1a under very mild conditions to give pyrimidine carbonitriles 6, 7 and quinazoline carbonitriles 13, 14.Direct synthesis of quinoxaline carbonitriles 19 is possible by reaction of chloroquinoxalines 15, 18 with 1a.
- Hermann, Klaus,Simchen, Gerhard
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p. 333 - 341
(2007/10/02)
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