Nuclear magnetic resonance has been employed to characterize fourteen new antibiotics belonging to the quinoxaline group, produced by feeding aromatic acids to Streptomyces echinatus. Twelve of the antibiotics are the expected substituted quinomycins and adopt conformations very similar to that of echinomycin. This is discussed in relation to their different DNA-binding characteristics. The oth...

The complete mol-ecule of the title compound, C(12)H(12)N(2)O(2), lies on two crystallographic symmetry elements: a twofold axis and a mirror plane. In the mol-ecular structure, the quinoxaline ring and two methyl-ene substituents lie on the mirror plane while the other two methyl-ene groups are disordered about the plane. The crystal packing is stabilized by weak inter-molecular π-π stacking i...

There are two mol-ecules in the asymmetric unit of the title compound, C(14)H(10)ClN(3), with dihedral angles of 5.11 (10) and 13.61 (10)° between the aromatic ring systems. In the crystal structure, mol-ecules are linked by N-H⋯N hydrogen bonds, resulting in chains propagating in [010].

In this work, the efficiency, generality and applicability of new Bronsted acidic ionic liquid (BAIL) 1-methyl-3-(2-(sulfooxy)ethyl)-1H-imidazol-3-ium chloride {[Msei]Cl} as heterogeneous and green catalyst for organic transformations are studied. Herein, the following one-pot multi-component reactions in the presence of [Msei]Cl are investigated: (i) the synthesis of quinoxaline derivatives fr...

The title compound, C18H10Cl2N4, synthesized by the condensation reaction between 4,5-di-chloro-benzene-1,2-di-amine and 1,2-di(pyridin-2-yl)ethane-1,2-dione in boiling acetic acid, has a nearly planar quinoxaline moiety [maximum deviation = 0.070 (1) Å] whose mean plane makes dihedral angles of 40.51 (2) and 39.29 (3)° with the pyridine rings. Within the unit cell, there are no classical hydro...

A series of quinoxaline 1,4-di-N-oxide analogues were prepared from benzofurazan N-oxide derivatives and β-diketone ester compounds by the improved Beirut reaction. The structures of the target products were characterized by NMR, MS, IR and elemental analysis measurements, and that of 2-carbomethoxy-3-hydroxyquinoxaline- di-N-oxide was further confirmed by single-crystal X-ray diffraction. Its ...

10-Ethyl-7-oxo-7,10-dihydropyrido[2,3-f]quinoxaline derivatives, synthesized as promising biologically/photobiologically active compounds were characterized by UV/vis, FT-IR and fluorescent spectroscopy. Photoinduced processes of these derivatives were studied by EPR spectroscopy, monitoring in situ the generation of reactive intermediates upon UVA (λmax=365 nm) irradiation. The formation of re...

An investigation on the effect of substituent at the 2-position of mono-substituted quinoxalines in the synthesis of di-substituted quinoxaline derivatives via nucleophilic substitution reactions, is reported. Di-substituted quinoxalines bearing aryl-alky, aryl-aryl, aryl-heteroaryl, aryl-alkynyl, and amino-alkyl substituents were prepared in moderate to good yields. 2-Monosubstituted quinoxali...

Molecular modelling studies were performed on some previously reported novel quinoxaline-2-carboxamide 1,4-di-N-oxide derivatives (series 1-9). Using the LigandScout program, a pharmacophore model was developed to further optimize the antimycobacterial activity of this series of compounds. Using the Dock6 program, docking studies were performed in order to investigate the mode of binding of the...