Synthesis, antibacterial and anticancer activity of azo-based and aminomethylene derivatives of cyclic β-keto sulfones

Herein we describe efficient and cost-effective synthesis of azo-based and aminomethylene derivatives of cyclic β-keto sulfones, specifically, 4,4-disubstituted (E)-2-(2-phenylhydrazineylidene)dihydrothiophen-3(2H)-one 1,1-dioxides and 4,4-disubstituted (E)-2-((methylamino)methylene)dihydrothiophen-3(2H)-one 1,1-dioxides. The azo-based derivatives were prepared through the azo coupling of cyclic β-keto sulfones with aromatic diazonium acetates, in situ prepared by diazotization of appropriate substituted amino benzenes. The aminomethylene derivatives were synthesized through the condensation of cyclic β-keto sulfones with DMF-DMA followed by a transamination reaction with primary amines. The target products were obtained in good yields and their structure was unambiguously established based on NMR spectra data, X-ray diffraction study, and DFT calculations. These compounds were designed as cost-effective and multitarget biologically active compounds. Further in vitro study showed antibacterial activity against Staphylococcus aureus and cytotoxicity against the MDA-MB-231 breast cancer cell line without affecting non-malignant cells MAEC. The molecular docking study confirmed good binding affinity of the studied compounds for DHPS, crucial for the bacterial life cycle and for CLK4 and IDO1, which are the therapeutic targets in cancer treatment.

Schiff bases targeting an Sw-480 colorectal cell line: synthesis, characterization, ds-DNA binding and anticancer studies

In present studies, six Schiff bases were prepared, characterized and evaluated for their anti-tumor activity against the colorectal cancer cell line SW-480. The test compounds were characterized by various physico-chemical techniques such as M. P., TLC, UV, FT-IR, elemental analysis, 1H-NMR spectroscopy etc. and investigated for their non-covalent DNA binding potential. The electronic absorption and hydrodynamic studies expressed strong complementary evidence that the Schiff bases are binding between the narrow walls of the helical DNA grooves and were stabilized via electrostatic interactions through groove binding as the dominant binding mode. Moreover, these studies also revealed that the tested compound had significant non-covalent binding to chicken (ck) blood ds-DNA at blood pH (7.4) and body temperature 310 K: the calculated values of standard Gibbs free energy changes (ΔG = -RT ln K f) for all compounds were negative which manifested the spontaneity of binding for all compounds. The cytotoxicity of the compounds was found through triplicate testing and the O. D. values were compared to find the percentage viability of the cells. The IC50 values of the compounds were estimated through dose-dependent curves. HSB3, HSB4 and HSB1 showed relatively potent anti-cancer activity with IC50 values of 7.0913 μg mL-1, 17.1469 μg mL-1 and 17.5254 μg mL-1, respectively. The same compounds had also exhibited relatively better ds-DNA binding efficacy with binding constant values (9.1 × 105, 3.5 × 105 and 5.13 × 104 respectively).

Cascade Alkynyl Prins Cyclization and Aza-Michael Reaction: En Route to Regioselective Pyrano- and Isochromenoquinoline Scaffolds

A metal-free, Lewis acid approach for the regioselective synthesis of dihydropyranoquinoline scaffolds has been unveiled. The methodology employs a cascade alkynyl Prins-aza-Michael reaction sequence to deliver the products in good to excellent yields. The strategy features mild reaction conditions, broad substrate scope, and high functional group tolerance. The protocol has been further extended to include isochromenoquinoline derivatives. The utility of the reaction lies in the synthesis of highly fused polycyclic N,O-heterocycles via intramolecular Heck coupling. Additionally, a Rh(III)-catalyzed annulation results in the formation of highly fluorescent pentacyclic ammonium salts in excellent yields. Photophysical studies reveal that these pentacyclic ammonium salts exhibit strong emission in the green region (500-550 nm).

Nonlinear optical properties of azo sulfonamide derivatives

CONTEXT

The present work deals with the linear and nonlinear optical properties such as the dipole moment, polarizability, total hyperpolarizability, electric field-induced second harmonic generation, and hyper-Rayleigh scattering first hyperpolarizability of four heterocyclic azo compounds containing the sulfonamide group considered promise in nonlinear optic. The obtained polarizability and hyperpolarizability were supported by the frontier molecular orbital analysis. The properties have been effectively estimated and thoroughly examined to shed light on the nonlinear optical activity based on the density functional theory. The observed results show a high total first hyperpolarizability β tot up to 2503 a.u. and a low energy gap E g less than 1.41 eV. An inverse relationship has been obtained between the β tot and E g . The calculated E g values confirm that charge occurs within the azo sulfonamides. The new study provides a promising avenue for the development of these azo sulfonamides as novel NLO materials.

METHODS

The molecular modeling and the theoretical studies were performed with Gaussian software packages. The B3LYP/6-311 + G** level was used for optimization. All the linear and nonlinear optical properties reported here are obtained using the DFT. The optimized structures and their frontier molecular orbitals were plotted using the GaussView 5.1 program.

Synthesis and Antibacterial Activity of Azo-Sulfa-Based Disperse Dyes and Their Application in Polyester Printing

For conjugating sulfa drug moieties with Schiff’s bases scaffold in the same build through an azo linker to take advantage of the bioactive feature of both motifs, we designed and synthesized a series of bioactive disperse dyes. The target disperse dyes, methyl 2-(E-2-hydroxy-5-((E)-(4-sulfa-derivative) diazenyl)benzylidene) hydrazine-1-carbodithioates 4a–e have been synthesized via the acidic reaction of azo dyes 3a–e with methyl hydrazine carbodithioate. Structures of the synthesized dyes were clarified based on their spectral and elemental analyses. The effectiveness of the dyes was initially tested as an antibacterial toward Staphylococcus aureus ATCC 6538-P and Escherichia coli ATCC 25933. Dyes that were proven to be effective against bacteria have been used as disperse dyes to print polyester fabrics. The color properties of the dyes and their fastness properties counting washing, perspiration, light, rubbing, and sublimation fastness were also examined. The printed polyester fabrics were evaluated for their antibacterial activity via colony-forming unit (CFU) technique. Fabric samples treated with 4c, 4d, and 4b had promising anti-Gram-positive activities against S. aureus. Whereas 4c-, 4d-, and 4b-treated fabrics exhibited moderate anti-Gram-negative activities against the test bacterium E. coli.

Anticancer Activities of Re(I) Tricarbonyl and Its Imidazole-Based Ligands: Insight from a Theoretical Approach

Rhenium complexes have been observed experimentally to exhibit good inhibitory activity against malignant cells. Hence, our motivation is to explore this activity from a theoretical perspective. In the present study, density functional theory (DFT) and in silico molecular docking approaches were utilized to unravel the unique properties of metal-based rhenium tricarbonyl complexes as effective anticancer drugs. All DFT calculations and geometric optimizations were conducted using the well-established hybrid functional B3LYP-GD(BJ)/Gen/6-311++G(d,p)/LanL2DZ computational method. The FT-IR spectroscopic characterization of the complexes: fac-[Re(Pico)(CO)₃(Pz)] (R1), fac-[Re(Pico)(CO)₃(Py)] (R2), fac-[Re(Dfpc)(CO)₃(H₂O)] (R3), fac-[Re(Dfpc)(CO)₃(Pz)] (R4), fac-[Re(Dfpc)(CO)₃(Py)] (R5), fac-[Re(Tfpc)(CO)₃(H₂O)] (R6), fac-[Re(Tfpc)(CO)₃(Py)] (R7), and fac-[Re(Tfpc)(CO)₃(Im)] (R8) was explored. To gain insights into the electronic structural properties, bioactivity, and stability of these complexes, the highest occupied molecular orbital-lowest unoccupied molecular orbital analysis, binding energy, and topological analysis based on quantum theory of atoms-in-molecules were considered. The anticancer activities of the complexes were measured via in silico molecular docking against human BCL-2 protein (IG5M) and proapoptotic (agonist) BAX 1 protein (450O). The results showed that the studied complexes exhibited good binding affinity (-3.25 to -10.16 kcal/mol) and could cause significant disruption of the normal physiological functions of the studied proteins. The results of DFT calculations also showed that the studied complexes exhibited good stability and are suitable candidates for the development of anticancer agents.

The effect of Azo-dyes on glioblastoma cells in vitro

Despite the multidisciplinary standard treatment of glioblastoma (GB) consisting of maximal surgical resection, followed by radiotherapy (RT) plus concomitant chemotherapy with temozolomide (TMZ), the majority of patients experience tumor progression and almost universal mortality. In recent years, efforts have been made to create new agents for GB treatment, of which azo-dyes proved to be potential candidates, showing antiproliferative effects by inducing apoptosis and by inhibiting different signaling pathways. In this study we evaluated the antiproliferative the effect of six azo-dyes and TMZ on a low passage human GB cell line using MTT assay. We found that all compounds proved antiproliferative properties on GB cells. At equimolar concentrations azo-dyes induced more cytotoxic effect than TMZ. We found that Methyl Orange required the lowest IC₅₀ for 3 days of treatment (26.4684 μM), whilst for 7 days of treatment, two azo dyes proved to have the highest potency: Methyl Orange IC₅₀ = 13.8808 μM and Sudan I IC₅₀ = 12.4829 μM. The highest IC₅₀ was determined for TMZ under both experimental situations. Conclusions: Our research represents a novelty, by offering unique valuable data regarding the azo-dye cyototoxic effects in high grade brain tumors. This study may focus the attention on azo-dye agents that may represent an insufficient exploited source of agents for cancer treatment.

Physicochemical Properties of a Bi-aromatic Heterocyclic-Azo/BSA Hybrid System at the Air-Water Interface

The interaction of a heterocyclic azo compound with itself and with bovine serum albumin (BSA) is realized by probing the structural modifications in Langmuir (L) monolayers and Langmuir-Blodgett (LB) films. It was found from the pressure-area/molecule isotherms that the elastic, thermodynamic, and hysteretic properties of the pure azo L monolayer were strongly altered due to the variation of temperature and pH of subphase water. In addition to that, the modification of such properties of the azo L monolayer due to mixing with BSA was also studied. The incorporation of BSA within the azo molecular assembly reduced the elasticity of that assembly. Such reduction of in-plane elasticity of the pure azo monolayer can also be achieved by reducing the temperature and pH of subphase water without adding BSA. A reduction in area per molecule of the azo assembly at the air-water interface associated with the conformational change from horizontal to vertical orientation facilitating π-π interaction was observed with increase in temperature and pH of the subphase. Such parameters also affected the interactions between azo and BSA molecules within the azo/BSA binary system. The structures of pure azo and binary films can be determined after they are transferred to hydrophilic and hydrophobic Si surfaces using the LB technique. Their out-of-plane and in-plane structures, as extracted from two complementary surface sensitive techniques, X-ray reflectivity and atomic force microscopy, were found to be strongly dependent on mixing with BSA, subphase pH, temperature, and substrate nature.