11H-Indeno[1,2-b]quinoxalin-11-one 2-(4-ethylbenzylidene)hydrazone

11H-Indeno[1,2-b]quinoxaline derivatives present an important type of nitrogen-containing heterocyclic compound that are useful intermediate products in organic synthesis and have potential pharmaceutical applications. A new 11H-indeno[1,2-b]quinoxalin-11-one-2-(4-ethylbenzylidene)hydrazone (compound 3) was synthesized. Compound 3 is the first example of an azine derivative based on the 11H-indeno[1,2-b]quinoxaline system. The Z,E-isomerism of compound 3 was investigated by DFT calculations. Bioavailability was evaluated in silico using ADME predictions. According to the ADME results, compound 3 is potentially highly bioavailable and has potential to be used for the treatment of neuroinflammation and ischemia–reperfusion injury.

7,8-Dimethyl-11H-indeno[1,2-b]quinoxalin-11-one

In the title compound, C17H12N2O, the mean planes of the indene ring and quinoxaline system (r.m.s. deviations = 0.0131 and 0.0082 Å) are approximately parallel to one another, making a dihedral angle of 1.2 (5)°. This means that the indeno[1,2-b]quinoxaline ring is almost in the same plane (r.m.s. deviation = 0.0181 Å).

{1′-Phenyl-1′,2′,5′,6′,7′,7a'-hexahydrospiro[indeno[1,2-b]quinoxaline-11,3′-pyrrolizin]-2′-yl}(p-tolyl)methanone

In the title compound, C35H29N3O, the quinoxaline and indene systems are essentially planar, with maximum deviations of 0.047 (2) and 0.032 (2) Å for C atoms, respectively. The quinoxaline system forms a dihedral angle of 4.75 (3)° with the indene system. The pyrrolizine system is folded. The substituted five-membered ring adopts an envelope conformation. In the other five-membered ring, one C atom is disordered with a site-occupancy ratio of 0.676 (12):0.324 (12). In the crystal, molecules are linkedviaC—H...O hydrogen bonds involving the bifurcated carbonyl O atom.

4-[3-(4-Fluorophenyl)quinoxalin-2-yl]-N-isopropylpyridin-2-amine

In the crystal structure of the title compound, C22H19FN4, the quinoxaline system makes dihedral angles of 32.07 (13) and 69.64 (13)° with the 4-fluorophenyl and pyridine rings, respectively. The 4-fluorophenyl ring makes a dihedral angle of 71.77 (16)° with the pyridine ring. The crystal structure is stabilized by intermolecular N—H...N hydrogen bonding.