Synthesis, characterization and bioactivity of new pyridine-2(H)-one, nicotinonitrile, and furo[2,3-b]pyridine derivatives

Pyridone heterocycles, such as furo[2,3-b]pyridines, have emerged as prominent scaffolds in medicinal chemistry due to their versatile pharmacological properties, including significant anticancer activity. In this study, we successfully synthesized new pyridine-2(H)-one, nicotinonitrile, and furo[2,3-b]pyridine derivatives from chalcones bearing 4-(benzyloxy)phenyl and dichlorothiophenyl subunits to explore their therapeutic potential against breast cancer. By employing a synthetic strategy involving Claisen-Schmidt condensation followed by sequential cyclizations and functional modifications, we synthesized and characterized four compounds (MI-S0, MI-S1, MI-S2, and MI-S3) using various spectroscopic methods, including FT-IR, 1H-NMR, 13C-NMR, DEPT, H,H- and C,H-COSY, and HRMS. The in vitro cytotoxic activity of these compounds was evaluated against two breast cancer cell lines, MCF-7 and MDA-MB-231, and compared with a noncancerous breast cell line, MCF-10A. All compounds exhibited potent cytotoxic activities with minimal selectivity toward normal cells. Molecular docking studies targeting the serine/threonine kinase AKT1, estrogen receptor alpha (ERα), and human epidermal growth factor receptor 2 (HER2) revealed strong binding affinities, suggesting a mechanism involving the disruption of key cellular signaling pathways. These findings underscore the potential of furo[2,3-b]pyridine derivatives as promising candidates for further development into anticancer agents, laying the groundwork for future investigations into their selective therapeutic efficacy and molecular mechanisms of action.

Investigation of Solvent Effect and H-Bonding on Spectroscopic Properties of 1-(3-Amino-6-(2,5-dichlorothiophen-3-yl)-4-phenylfuro[2,3-b]Pyridin-2-yl) Ethenone: Experimental and Computational Study

The furo[2,3-b]pyridine moiety is an important scaffold for many biologically active compounds, therefore, the spectral data of the derivative 1-(3-Amino-6-(2,5-dichlorothiophen-3-yl)-4-phenylfuro[2,3-b]pyridin-2-yl) ethenone (FP1) were investigated. Analysis of absorption-pH profile and Förster cycle of FP1 revealed that its excited state is more acidic than its ground state ([Formula: see text] < [Formula: see text]). The main fluorescence emission band of FP1 at 480 nm (in hexane) is shifted to longer wavelengths with increasing polarities of solvents. Linear Lippert's plot and linear correlation between bands maxima and Camlet-Taft parameter, α, of the protic solvents indicated efficient intramolecular charge transfer and noticeable H-bonding. Moreover, the disappearance of the absorption band of FP1 at 385 nm in water, along with the noticeable red shift and quenching of the emission band, and the lower lifetime, relative to nonaqueous solvents, indicate the interruption of the furo[2,3-b]pyridine aromatic moiety. In addition, results from the Time Dependent Density Functional Theory (TDDFT) and Molecular Mechanic (MM) calculations were in agreement with experimentally determined spectra of FP1.

Synthesis of 1-Amino-3-oxo-2,7-naphthyridines via Smiles Rearrangement: A New Approach in the Field of Chemistry of Heterocyclic Compounds

In this paper we describe an efficient method for the synthesis of new heterocyclic systems: furo[2,3-c]-2,7-naphthyridines 6, as well as a new method for the preparation of 1,3-diamino-2,7-naphthyridines 11. For the first time, a Smiles rearrangement was carried out in the 2,7-naphthyridine series, thus gaining the opportunity to synthesize 1-amino-3-oxo-2,7-naphthyridines 4, which are the starting compounds for obtaining furo[2,3-c]-2,7-naphthyridines. The cyclization of alkoxyacetamides 9 proceeds via two different processes: the expected formation of furo[2,3-c]-2,7-naphthyridines 10 and the ‘unexpected’ formation of 1,3-diamino-2,7-naphthyridines 11 (via a Smiles type rearrangement).

The Synthesis, Characterization, Cytotoxic Activity Assessment and Structure-Activity Relationship of 4-Aryl-6-(2,5-dichlorothiophen-3-yl)-2-methoxypyridine-3-carbonitriles

A series of 2-methoxypyridine-3-carbonitrile (5a–i)-bearing aryl substituents were successfully synthesized in good yields by the condensation of chalcones (4a–i) with malononitrile in basic medium. The condensation process, in most cases, offers a route to a variety of methoxypyridine derivatives (6a–g) as side products in poor yields. All new compounds were fully characterized using different spectroscopic methods. Mass ESI-HMRS measurements were also performed. Furthermore, these compounds were screened for their in vitro cytotoxicity activities against three cancer cell lines; namely, those of the liver (line HepG2), prostate (line DU145) and breast (line MBA-MB-231). The cytotoxicity assessment revealed that compounds 5d, 5g, 5h and 5i exhibit promising antiproliferative effects (IC₅₀ 1–5 µM) against those three cancer cell lines.