Synthesis, characterization, antifungal activities and crystal structure of thiophene-based heterocyclic chalcones

Synthesis of Chalcones Derivatives and Their Biological Activities: A Review

Chalcone derivatives are considered valuable species because they possess a ketoethylenic moiety, CO-CH=CH-. Due to the presence of a reactive α,β-unsaturated carbonyl group, chalcones and their derivatives possess a wide spectrum of antiproliferative, antifungal, antibacterial, antiviral, antileishmanial, and antimalarial pharmacological properties. Recent developments in heterocyclic chemistry have led to the synthesis of chalcone derivatives, which had been biologically investigated toward certain disease targets. The major aspect of this review is to present the most recent synthesis of chalcones bearing N, O, and/or S heterocycles, revealing their biological potential during the past decade (2010-2021). Based on a review of the literature, many chalcone-heterocycle hybrids appear to exhibit promise as future drug candidates owing to their similar or superior activities compared to those of the standards. Thus, this review may prove to be beneficial for the development and design of new potent therapeutic drugs based on previously developed strategies.

Novel thiophene Chalcones-Coumarin as acetylcholinesterase inhibitors: Design, synthesis, biological evaluation, molecular docking, ADMET prediction and molecular dynamics simulation

A series of around eight novel chalcone based coumarin derivatives (23a-h) was designed, subjected to in-silico ADMET prediction, synthesized, characterized by IR, NMR, Mass analytical techniques and evaluated as acetylcholinesterase (AChE) inhibitor for the treatment of Alzheimer's disease (AD). The results of predicted ADMET study demonstrated the drug-likeness properties of the titled compounds with developmental challenges in lipophilicity and solubility parameters. The in vitro assessment of the synthesized compounds revealed that all of them showed significant activity (IC₅₀ ranging from 0.42 to 1.296 µM) towards AChE compared to the standard drug, galantamine (IC₅₀ = 1.142 ± 0.027 µM). Among these, compound 23e displayed the most potent inhibitory activity with IC₅₀ value of 0.42 ± 0.019 µM. Cytotoxicity of all compounds was tested on normal human hepatic (THLE-2) cell lines at three different concentrations using the MTT assay, in which none of the compound showed significant toxicity at the highest concentration of 1000 µg/ml compared to the control group. Based on the docking study against AChE, the most active derivative 23e was orientated towards the active site and occupied both catalytic anionic site (CAS) and peripheral anionic site (PAS) of the target enzyme. In-silico studies revealed tested showed better inhibition activity of AChE compared to Butyrylcholinesterase (BuChE). Molecular dynamics simulation explored the stability and dynamic behavior of 23e- AChE complex.

Hyperpolarizability studies and Hirshfeld surface analysis of two heterocyclic chalcones

In this work, the nonlinear optical (NLO) properties of two heterocyclic chalcones, (E)-1-(5-chlorothiophen-2-yl)-3-(thiophen-2yl)-2-propen-1-one (CLTT) and (E)-1-(5-methylfuran-2-yl)-3-(5-methylthiophen-2-yl)prop-2en-1-one (2MFT), are investigated. Using an iterative electrostatic embedding approach via the Møller-Plesset perturbation (MP2) theory, the chalcone crystals were simulated and the polarization effects on the isolated molecules are investigated. The electrical parameters of CLTT and 2MFT as dipole moment and linear polarizability were calculated via MP2/6-311++G(d) and the second hyperpolarizability was obtained via DFT/CAM-B3-LYP/6-311++G(d) level. A significant influence of the molecular packing on the chalcone electric parameters was observed. The static linear refractive index and the third-order electric susceptibility of the compounds were calculated and compared with experimental results available for other chalcone derivatives, indicating the CLTT crystal as a promising candidate for NLO applications in photonic and optoelectronic devices. The Hirshfeld surface analysis has been used to quantify the intermolecular interactions of the molecular crystals. Additionally, the solvent medium effects on the electrical properties of the heterocyclic chalcones were also studied.

Studies via X-ray analysis on intermolecular interactions and energy frameworks based on the effects of substituents of three 4-aryl-2-methyl-1H-imidazoles of different electronic nature and their in vitro antifungal evaluation

The crystal structures of 2-methyl-4-phenyl-1H-imidazole, C₁₀H₁₀N₂, (3a), 4-(4-chlorophenyl)-2-methyl-1H-imidazole hemihydrate, C₁₀H₉ClN₂·0.5H₂O, (3b), and 4-(4-methoxyphenyl)-2-methyl-1H-imidazole, C₁₁H₁₂N₂O, (3c), have been analyzed. It was found that the electron-donating/withdrawing tendency of the substituent groups in the aryl ring influence the acid-base properties of the 2-methylimidazole nucleus, changing the strength of the intermolecular N-H...N interactions. This behaviour not only influences the crystal structure but also seems to have an important effect on the antifungal activity. Considering the substituent groups, that is, H in (3a), Cl in (3b) and OMe in (3c), the formation of strong N-H...N connections has the probability (3a) > (3b) > (3c), while compound (3c) proves to be more active than (3a) and (3b) at all concentrations against C. neoformans.

Crystal structure of 4-amino-3-(thio-phen-3-ylmeth-yl)-1H-1,2,4-triazole-5(4H)-thione

In the title compound, C7H8N4S2, the thio-phene ring shows rotational disorder over two orientations in a 0.6957 (15):0.3043 (15) ratio. The plane of the 1,2,4-triazole ring makes a dihedral angle of 75.02 (17)° with the major-disorder component of the thiophene ring. In the crystal, two types of inversion dimers, described by the graph-set motifs R22(8) and R22(10), are formed by N-H⋯S inter-actions. Chains of mol-ecules running in the [101] direction are linked by weaker N-H⋯N inter-actions. The thio-phene ring is involved in π-π and C-H⋯π inter-actions.