The quinoxaline antibiotics are cyclic depsipeptides characterized by the presence of two heterocyclic aromatic chromophores and a cross-bridge, which is either a dithioacetal (quinomycins) or a disulphide (triostins). In the naturally-occurring members of this class the chromophores are both quinoxaline-2-carboxyl (shown as the parent acid in 1). There are natural variants in the class due to ...

The interaction with DNA of six chemically synthesized derivatives of the quinoxaline antibiotics was investigated. Five of the compounds bound only weakly to DNA or not at all; for these substances spectrophotometric measurements, sedimentation studies with closed circular duplex bacteriophage-PM2 DNA and thermal-denaturation profiles were used to determine limits fot the binding constants. No...

The malignant transformation of melanocytes causes several thousand deaths each year, making melanoma an important public health concern. Melanoma is the most aggressive skin cancer, which incidence has regularly increased over past decades. We described here preparation new compounds based on 1-(3,4-dihydroxyphenyl)imidazo[1,2-a]quinoxaline structure. Different positions quinoxaline moiety wer...

Novel naphtho[2,3-f]quinoxaline-2,7,12(1H)-trione and anthra-9,10-quinone dyes were synthesized in good yield from furan-2,3-diones using 1,2-diaminoanthra-9,10-quinone and 1,4-diaminoanthra-9,10-quinone. The chromophores were characterized by molecular spectroscopy methods.

This work presents the development of a quinoxaline and rhodamine conjugate system that acts as colorimetric chemosensor for hydrogen sulfate (HSO4?) ions in methanol media. sensor has been characterized both theoretically experimentally. The detection limits HSO4? are small 0.71 µM 3.8 absorption emission experiments, respectively. effectiveness probe recognizing gel solid phase is evaluated w...

As a continuation of our research in the quinoxaline 1,4-di-N-oxide new series of 2-arylcarbonyl-3-trifluoromethylquinoxaline, 1,4-di-N-oxide derivatives have been synthesized and evaluated in a full panel of 60 human tumor cell lines. Selective reductions were carried out on two compounds which allowed us to determine the compound structures by comparison of the 1H NMR spectra. In general, all...

Two new 5,12-disubstituted 2,3-di-ethyl-naphtho-[2,3-g]quinoxaline-6,11-dione compounds were readily synthesized from the commercial dye quinizarin. For 2,3-diethyl-5,12-di-hydroxy-naphtho-[2,3-g]quinoxaline-6,11-dione, (II), C20H16N2O4, the mol-ecule displays a near planar conformation and both hy-droxy groups participate in intra-molecular O-H⋯O(carbon-yl) hydrogen bonds. In the crystal, π-π ...

As a continuation of our research and with the aim of obtaining new agents against Chagas disease, an extremely neglected disease which threatens 100 million people, eighteen new quinoxaline 1,4-di-N-oxide derivatives have been synthesized following the Beirut reaction. The synthesis of the new derivatives was optimized through the use of a new and more efficient microwave-assisted organic synt...

Eight forms of human liver microsomal P-450 were individually expressed in human hepatoma Hep G2 cells with a vaccinia virus cDNA expression system. Using the Ames test, each expressed P-450 was examined for its ability to activate to mutagenic products the compounds, 2-amino-3-methylimidazo[4,5-f]quinoline, 2-amino-3,4-dimethylimidazo[4,5-f]quinoline, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxal...