Synthesis, antioxidant and toxicological study of novel pyrimido quinoline derivatives from 4-hydroxy-3-acyl quinolin-2-one

A one-pot-three-step route to triazolotriazepinoindazolones from oxazolino-2H-indazoles

A one-pot-three-step method has been developed for the conversion of oxazolino-2H-indazoles into triazolotriazepinoindazolones with three points of diversity. Step one of this process involves a propargyl bromide-initiated ring opening of the oxazolino-2H-indazole (available by the Davis-Beirut reaction) to give an N(1)-(propargyl)-N(2)-(2-bromoethyl)-disubstituted indazolone, which then undergoes -CH(2)Br → -CH(2)N(3) displacement (step two) followed by an uncatalyzed intramolecular azide-alkyne 1,3-dipolar cycloaddition (step three) to form the target heterocycle. Employing 7-bromooxazolino-2H-indazole allows for further diversification through, for example, palladium-catalyzed coupling chemistry, as reported here.

Synthesis and biological evaluation of novel pyrazoline derivatives as anti-inflammatory and antioxidant agents

A series of novel 5-aryl-3-cyclopropyl-4,5-dihydropyrazole derivatives 2a-p were synthesized via cyclization of chalcones 1a-h with thiosemicarbazide or semicarbazide HCl and evaluated as anti-inflammatory/antioxidant agents. The structures were confirmed by elemental analyses and spectral data. The free radical scavenging activity toward superoxide was determined. Their effect on hepatocytes viability and nitric oxide (NO) production in LPS-stimulated macrophages was also determined. The results showed that compounds 2e and 2n demonstrated the highest free-radical scavenging and anti-inflammatory activities, thus can be useful in the prevention of oxidative stress and inflammation-related disorders.

Unusual open chain quinolinyl peroxol and its alcohol counterpart obtained through a modified Skraup-Doebner-Von Miller quinoline synthesis: theoretical studies and complete (1) H- and (13) C-NMR assignments

Because of their extreme instability, it is generally difficult to synthesize and fully characterize open chain peroxides, also known as peroxols. In our attempt to investigate the mechanism of the Skraup-Doebner-Von Miller quinoline synthesis, we were able to obtain an unusual open chain peroxy-quinoline, namely, 4-(8-ethoxy-2,3-dihydro-1H-cyclopenta[c]quinolin-4-yl)butane-1-peroxol (1), and its alcohol counterpart, namely 4-(8-ethoxy-2,3-dihydro-1H-cyclopenta[c]quinolin-4-yl)butan-1-ol (2) obtained as a side product during the same reaction. Although structurally similar, these two compounds appeared to display some very distinct physical and spectroscopic characteristics. This work reports detailed NMR studies and full (1) H and (13)  C NMR assignments for these two compounds. These assignments are based upon the analysis of the NMR spectra of these compounds including (1) H, (13)  C, COSY, gHSQC and gHMBC. The effect of the peroxide functional group on the chemical shift of neighboring carbons and protons was also investigated by comparing the NMR data of these two compounds. Furthermore, the effects of potential hydrogen bondings in 1, 2, and possible 1-1 dimer, 2-2 dimer and in prototypical model systems, as well as the stability of these compounds, were investigated computationally. The computed dissociation energies and NMR data support the interpretation of the experimental data.

1-[2-(4-Nitrophenyl)-5-(5-phenyl-1,2-oxazol-3-yl)-1,2,3,4-tetrahydroquinolin-4-yl]pyrrolidin-2-one

The title compound, (I) C₂₈H₂₄N₄O₄, is the trans diastereo­isomer of the compound 1-[2-(4-nitro­phen­yl)-6-(5-phenyl-3-isoxazol­yl)-1,2,3,4-tetra­hydro-4-quinolin­yl]-2-pyrrolidinone monohydrate, (II) [Gutierrez et al. (2011 ▶). Acta Cryst. E67, o175–o176]. The most obvious differences between the diastereo­isomers are the dihedral angles between the isoxazole ring and the benzene and phenyl rings [47.0 (2); 56.4 (2) and 33.3 (2); 11.0 (2)°, respectively, for (II) 75.4 (2) and 5.8 (3), respectively, for (I)]. In the crystal of (I), the mol­ecules are linked by N—H⋯O inter­actions into a chain along [001] with graph-set notation C(8).

1-[2-(4-Nitro-phen-yl)-5-(5-phenyl-1,2-oxazol-3-yl)-1,2,3,4-tetra-hydro-quinolin-4-yl]pyrrolidin-2-one monohydrate

The title compound, C₂₈H₂₄N₄O₄·H₂O, crystallizes with two organic mol­ecules and two solvent water mol­ecules in the asymmetric unit. The most obvious difference between the mol­ecules is the torsion angles between the isoxazole ring and the benzene and phenyl rings [47.0 (2)/56.4 (2) and 33.3 (2)/11.0 (2)°, respectively]. Another important difference is observed in the rotation of the nitro group with respect to the phenyl groups [3.5 (6) and 31.1 (6)°]. The pyrrolidinone fragment is cis oriented with respect to the 4-nitro­phenyl fragment. In the crystal, mol­ecules are linked into centrosymmetric R₄²(8) and R₄⁴(20) motifs by O—H⋯O and N—H⋯O inter­actions.