Recent Methods for the Synthesis of Quinoxaline Derivatives and their Biological Activities

Annulation of 2-Aroyl D-A Cyclopropanes via Selectively Ring-Opening Process with o-Benzenediamines to Access Quinoxaline Derivatives

An annulation reaction of 2-aroyl D-A cyclopropanes with o-benzenediamines via selective cleavage of C-C bonds of cyclopropane in the presence of DBU/Sc(OTf)3 reaction systems was developed for the direct preparation of 2-aryl-3-benzylquinoxalines. This synthetic approach tolerated a wide range of readily available aroyl-substituted D-A cyclopropanes with diverse functional groups and had operationally simple and mild reaction conditions.

Synthesis, Spectral Characterization and Photoluminescence of 3-chloro-6-methoxy-2-(methylsulfanyl)quinoxaline in Different Solvents: An Experimental and Theoretical Investigation Using DFT

In the present work, we synthesized 3-chloro-6-methoxy-2-(methyl sulfanyl) quinoxaline (3MSQ) using a microwave-assisted synthesis method. The physicochemical structural analysis of the synthesized compound utilizing 1H-NMR, 13C-NMR, and FT-IR spectroscopy techniques. The photophysical properties of 3MSQ was examined through absorption and fluorescence spectroscopy. Spectroscopic analyses revealed a bathochromic shift in both absorption and fluorescence spectra, attributed to the π → π* transition. Ground and excited state dipole moments was experimentally determined using the solvatochromic shift method, employing various correlations such as Lippert's, Bakhshiev's, Kawski-Chamma-Viallet's equations, and solvent polarity parameters. Our findings indicate that the excited state dipole moments exceed those of the ground state, suggesting increased polarity in the excited state. Further, the while detailed bond length, bond angles, dihedral angles, Mulliken charge distribution, ground state dipole moments and HOMO-LUMO energy gap estimated through ab initio computations using Gaussian-09W. The value of energy band gap obtained from both the methods are in good agreement. Furthermore, employing DFT computational analysis, we identified reactive centers such as electrophilic and nucleophilic sites using molecular electrostatic potential (MESP) 3D plots. Additionally, CIE chromaticity analysis was performed to understand the photoluminescent properties of 3MSQ. The insights derived from these analyses contribute to a better understanding of the molecule's electronic structure, photophysical properties, and solute-solvent interactions, thus providing valuable information regarding its behaviour and characteristics under diverse conditions. These results contribute to a comprehensive understanding of the molecular structure and properties of 3-chloro-6-methoxy-2-(methyl sulfanyl) quinoxaline (3MSQ).

The patent review of the biological activity of tropane containing compounds

INTRODUCTION

Tropane-derived medications have historically played a substantial role in pharmacotherapy. Both natural and synthetic derivatives of tropane find application in addressing diverse medical conditions. Prominent examples of tropane-based drugs include hyoscine butylbromide, recognized for its antispasmodic properties, atropine, employed as a mydriatic, maraviroc, known for its antiviral effects. trospium chloride, utilized as a spasmolytic for overactive bladder, and ipratropium, a bronchodilator.

AREAS COVERED

We compiled patents pertaining to the biological activity of substances containing tropane up to the year 2023 and categorized them according to the specific type of biological activity they exhibit. ScienceFinder, ScienceDirect, and Patent Guru were used to search for scientific articles and patent literature up to 2023.

EXPERT OPINION

Pharmaceutical researchers in academic and industrial settings have shown considerable interest in tropane derivatives. Despite this, there remains a substantial amount of work to be undertaken. A focused approach is warranted for the exploration and advancement of both natural and synthetic bioactive molecules containing tropane, facilitated through collaborative efforts between academia and industry. Leveraging contemporary techniques and technologies in medicinal and synthetic chemistry, including high throughput screening, drug repurposing,and biotechnological engineering, holds the potential to unveil novel possibilities and accelerate the drug discovery process for innovative tropane-based pharmaceuticals.