Synthesis and pharmacological evaluation of antioxidant chalcone derivatives of 2(3H)-benzoxazolones

Ultrasound assisted synthesis and cytotoxicity evaluation of known 2',4'-dihydroxychalcone derivatives against cancer cell lines

This work reports on the development of an efficient and ecofriendly ultrasound assisted method for the high yield synthesis (70.0-94.0%) of eighteen oxyalkylated derivatives of 2',4'-dihydroxychalcone. Synthesized compounds were subjected to in vitro biological assays against HT-29 (colorectal), MCF-7 (breast), and PC-3 (prostate) human tumor cell lines, these cell lines are among the ten most aggressive malignancies diagnosed in the world. Cytotoxicity evaluations showed that four of the synthesized compounds exhibited moderate to very high toxic activity against MCF-7 (IC₅₀ = 8.4-34.3 μM) and PC-3 (IC₅₀ = 9.3-29.4 μM) - comparable to 5-fluorouracil (IC₅₀ 16.4-22.3 μM). The same compounds only showed moderate activity against HT-29 (IC₅₀ 15.3-36.3 μM), closer to daunorubicin (IC₅₀ 15.1 μM). Next, although selectivity index (SI) of compounds was weak, compound 18 exhibited a remarkable and selective cytotoxic activity (5.8-10.57) against cancer cells. Outside of these, most compounds significantly reduced cell survival, increased reactive oxygen species (ROS) and caspase activity, and decreased mitochondrial membrane permeability. In this sense, a portion of anti-proliferative activity is due to apoptosis. Notwithstanding, due to its remarkable response, chalcone 18 may be a potential alternative as a chemotherapeutic anti-carcinogen.

Design, synthesis and biological evaluation of new benzoxazolone/benzothiazolone derivatives as multi-target agents against Alzheimer's disease

In this study, four series of compounds with benzoxazolone and benzothiazolone cores were designed, synthesized and evaluated as multifunctional agents against Alzheimer's disease (AD). Additionally, in order to shed light on the effect of the carbonyl groups of benzoxazolone/benzothiazolone, benzoxazole/benzothiazole-containing analogues were also synthesized and evaluated. Inhibition potency of all final compounds towards cholinesterase enzymes and their antioxidant activity were tested. Subsequently, the anti-inflammatory activity, cytotoxicity, apoptosis, and Aβ aggregation inhibition tests were also performed for selected compounds. The results indicated that compounds 11c, a pentanamide derivative with benzothiazolone core, and 14b, a keton derivative with benzothiazolone core, were considered as promising multi-functional agents for further investigation against AD. The reversibility, kinetic and molecular docking studies were also performed for the compounds with the highest AChE 14b (eeAChE IC₅₀ = 0.34 μM, huAChE IC₅₀ = 0.46 μM) and BChE 11c (eqBChE IC₅₀ = 2.98 μM, huBChE IC₅₀ = 2.56 μM) inhibitory activities.

Synthesis, biological evaluation, quantitative-SAR and docking studies of novel chalcone derivatives as antibacterial and antioxidant agents

In the present study, a series of chalcone derivatives including 17 new compounds were synthesised; their antibacterial activities against eleven bacteria, and their free radical-scavenging activities using DPPH were evaluated. All compounds showed significant antibacterial activities against both Grampositive and Gram-negative bacteria. In particular, compound IIIf strongly inhibited Staphylococcus aureus (JMC 2151) and Enterococcus faecalis (CARS 2011-012) with MIC values of 6.25 μg mL

Molecular structure, spectral studies, intra and intermolecular interactions analyses in a novel ethyl 4-[3-(2-chloro-phenyl)-acryloyl]-3,5-dimethyl-1H-pyrrole-2-carboxylate and its dimer: A combined DFT and AIM approach

A newly synthesized chalcone, Ethyl 4-[3-(2-chloro-phenyl)-acryloyl]-3,5-dimethyl-1H-pyrrole-2-carboxylate (ECPADMPC) has been characterized by (1)H NMR, (13)C NMR, UV-Vis, FT-IR, Mass spectroscopy and elemental analysis. Quantum chemical calculations have been performed by DFT level of theory using B3LYP functional and 6-31G(d,p) as basis set. The time dependent density functional theory (TD-DFT) is used to find the various electronic transitions within molecule. A combined theoretical and experimental wavenumber analysis confirms the existence of dimer. Topological parameters-electron density (ρ(BCP)), Laplacian of electron density (∇(2)ρ(BCP)), energetic parameters-kinetic electron energy density (G(BCP)), potential electron density (V(BCP)) and the total electron energy density (H(BCP)) at the bond critical points (BCP) have been analyzed by 'Atoms in molecules' AIM theory in detail. The intermolecular hydrogen bond energy of dimer is calculated as -12.3kcal/mol using AIM calculations. AIM ellipticity analysis is carried out to confirm the presence of resonance assisted intermolecular hydrogen bonds in stabilization of dimer. The analysis clearly depicts the presence of different kind of interactions in dimer. This dimer may work as model system to understand the H-bonding interaction in biomolecules. The local reactivity descriptor analysis is performed to find the reactive sites within molecule.

(1E,4E)-1,5-Bis(thio-phen-3-yl)penta-1,4-dien-3-one

The title compound, C₁₃H₁₀OS₂, exhibits twists between the central C₃O and ethene residues [O—C—C—C torsion angles = −8.4 (3) and 11.8 (3)°], and between the ethene and adjacent thio­phenyl residues [C—C—C—C torsion angles = −4.2 (3) and 10.5 (3)°]. As a result, the mol­ecule is non-planar, the dihedral angle formed between the terminal thio­phenyl groups being 15.45 (10)°. The presence of C—H⋯O inter­actions involving the bifurcated carbonyl O atom leads to supra­molecular arrays in the ac plane. These are linked into a three-dimensional architecture by C—H⋯π inter­actions involving both thio­phenyl residues.

Synthesis and antimicrobial studies of hydroxylated chalcone derivatives with variable chain length

A series of (E)-1-(4-alkyloxyphenyl)-3-(hydroxyphenyl)-prop-2-en-1-one have been successfully synthesised via Claisen-Schmidt condensation. The synthesised chalcone derivatives consisted of hydroxyl groups at either ortho, meta or para position and differed in the length of the alkyl groups, C (n) H(2) (n) (+1,) where n = 6, 10, 12 and 14. The structures of all compounds were defined by elemental analysis, IR, (1)H- and (13)C-NMR. The antimicrobial studies were carried out against wild-type Escherichia coli American Type Culture Collection 8739 to evaluate the effect of the hydroxyl and the alkyl groups of the synthesised chalcones. All the synthesised compounds have shown significant antimicrobial activities. The optimum inhibition was dependent on the position of the hydroxyl group as well as the length of the alkyl chains.

(2E)-1-[2-Hydr-oxy-4-(2-methyl-prop-oxy)phen-yl]-3-(4-methyl-phen-yl)prop-2-en-1-one

The benzene rings in the title compound, C₂₀H₂₂O₃, form a dihedral angle of 10.39 (8)°. Overall, the mol­ecule is approximately planar with the exception of one of the terminal methyl groups; excluding this group, the r.m.s. deviation for the remaining 22 non-H atoms is 0.0968 Å. The conformation about the C=C bond is E, and an intra­molecular O—H⋯O hydrogen bond leads to the formation of an S(6) motif. In the crystal, linear supra­molecular chains are formed along the a axis via C—H⋯O contacts, and these are connected into double chains via C—H⋯π inter­actions.