Novel Derivatives of Benzo[b]thieno[2,3-c]quinolones: Synthesis, Photochemical Synthesis, and Antitumor Evaluation

A review on the synthesis of heteroannulated quinolones and their biological activities

The quinoline scaffold has become an important construction motif for the development of new drugs. The quinolones and their heteroannulated derivatives have high importance due to their diverse spectrum of biological activities as antifungal, anti-inflammatory, anti-diabetes, anti-Alzheimer's disease, antioxidant and diuretic activities. This review summarizes the various new, efficient and convenient synthetic approaches to synthesize diverse quinolone-based scaffolds and their biological activities. We also dealt with the important mechanism, the route and type of reactions of the obtained products. The biological activities of some heteroannulated quinolones were also discussed.

Unmasking Dipole Character of Acyl Ketene Dithioacetals via a Cascade Reaction with Arynes: Synthesis of Benzo[b]thiophenes

An unusual strategy toward novel substituted benzo[b]thiophenes has been developed. The generation of arynes in the presence of acyl ketene dithioacetals resulted in a cascade reaction involving [3 + 2] cycloaddition, and a dealkylative arylation of a thioether moiety to afford 2,3-disubstuted benzo[b]thiophenes. This route represents an expeditious approach to benzothiophenes that employs acyl ketene dithioacetals as dipoles.

Palladium-catalyzed intramolecular C–H arylation of 2-halo-N-Boc-N-arylbenzamides for the synthesis of N–H phenanthridinones

A palladium catalyzed synthesis of N–H phenanthridinones was developed via C–H arylation. The protocol gives phenanthridinones regioselectively by one-pot reaction without deprotection. It exhibits broad substrate scope and affords targets in up to 95% yields. Importantly, it could be applied for the less reactive o-chlorobenzamides.

Pd(t-Bu₃P)₂/KOAc proved to be a good combination for one-pot synthesis of N–H phenanthridinones with up to 95% yield.

Sequential hydroarylation/Prins cyclization: an efficient strategy for the synthesis of angularly fused tetrahydro-2H-pyrano[3,4-c]quinolines

Various aldehydes undergo a smooth cascade cyclization with N-(5-hydroxypent-2-yn-1-yl)-4-methyl-N-phenylbenzenesulfonamide in the presence of 10 mol% Ph₃PAuCl/AgSbF₆/In(OTf)₃ to furnish the corresponding tetrahydro-2H-pyrano[3,4-c]quinoline derivatives.

Synthesis, anticancer and radiosensitizing evaluation of some novel sulfonamide derivatives

In this study, novel series of sulfonamide derivatives were synthesized starting from 2-cyanoacetyl)hydrazono)ethyl)phenyl)benzenesulfonamide 4a and 2-cyanoacetyl)hydrazono)ethyl)phenyl)-4-methylbenzenesulfonamide 4b. Different biologically active moieties as pyrazol, thiophene, pyridine and pyrimidines were introduced in order to investigate their in-vitro anticancer activity, in addition to a novel series of sulfonamide chalcones were synthesized from the reported 4-acetyl-N-(P-tolyl) benzenesulfonamide 3b. The newly synthesized sulfonamide derivatives were characterized by FT-IR, (1)H NMR, (13)C NMR, mass spectroscopy and elemental analyses and were tested for their in-vitro anticancer activity against human tumor liver cell line (HEPG-2). The most potent compounds in this study were compounds 4a, 4b, 5a, 6a, 6b, 8, 9, 11, 13, 18 and 19 which showed higher activity than doxorubicin with IC50 ranging from 11.0 to 31.8 μM. Additionally, eight compounds among the most potent were evaluated for their ability to enhance the cell killing effect of γ-radiation.

QSAR analysis of antitumor active amides and quinolones from thiophene series

QSAR models for predicting antitumor activity of heterocyclic amides and quinolones from benzo[b]thiophene-, thieno[3,2-b]thiophene- and thieno[2,3-b], thiophene series against MiaPaCa-2 and MCF-7 cells were built. Complete dataset consisted of 59 compounds and several QSAR models with different predictive ability were derived. Beside standard approaches for building QSAR models, the approach based on a small dataset of 10 compounds selected regarding the results of principal component analysis was tested. The latter approach was shown as successful and can be useful for planning future experiments in order to speed up and simplify the search for new drug candidates. Based on the derived QSAR models, the most important properties for compound's antitumor activity against MiaPaCa-2 and MCF-7 cells were identified. Volume, sum of the hydrophobic surfaces and presence of the group that can be easily ionized in the pH range from 4 to 9, were found to be highly important for successful antitumor activity of the examined heterocyclic amides and quinolones. New compounds, with potentially higher biological activity against MiaPaCa-2 and MCF-7 cells, were proposed. Their activities were predicted using the derived QSAR models and the proposed compounds were shown as promising antitumor candidates.

Novel cyano- and amidino-substituted derivatives of thieno[2,3-b]- and thieno[3,2-b]thiophene-2-carboxanilides and thieno[3′,2′:4,5]thieno- and thieno[2′,3′:4,5]thieno [2,3-c]quinolones: Synthesis, photochemical synthesis, DNA binding, and antitumor evaluation

A series of cyano- and amidino-substituted derivatives of thieno[2,3-b]- and thieno[3,2-b]thiophene-2-carboxanilides and their 'cyclic' derivatives (quinolones) were synthesized. 'Cyclic' compounds displayed a rather strong and differential antiproliferative effect on various cell lines, while the 'acyclic' amidino-substituted compounds were much more active, but showing mostly non-differential cytotoxicity, whereas cyano-substituted compounds (2a,b) produced a strikingly strong effect selectively on HeLa and Hep-2 cell lines. Antiproliferative activity of 'cyclic' derivatives is very likely caused by intercalation into DNA, while their 'acyclic' analogues use other target(s) and/or mechanisms of action.