Chemical structures and biological activities of bis- and tetrakis-acridine derivatives: A review

Facile and Novel Synthetic Approach, Molecular Docking, Molecular Dynamics, and Drug-Likeness Evaluation of 9-Substituted Acridine Derivatives as Dual Anticancer and Antimicrobial Agents

In the present study, numerous acridine derivatives A1-A20 were synthesized via aromatic nucleophilic substitution (SNAr) reaction of 9-chloroacridine with carbonyl hydrazides, amines, or phenolic derivatives depending upon facile, novel, and eco-friendly approaches (Microwave and ultrasonication assisted synthesis). The structures of the new compounds were elucidated using spectroscopic methods. The title products were assessed for their antimicrobial, antioxidant, and antiproliferative activities using numerous assays. Promisingly, the investigated compounds mainstream revealed promising antibacterial and anticancer activities. Thereafter, the investigated compounds' expected mode of action was debated by using an array of in silico studies. Compounds A2 and A3 were the most promising antimicrobial agents, while compounds A2, A5, and A7 revealed the most cytotoxic activities. Accordingly, RMSD, RMSF, Rg, and SASA analyses of compounds A2 and A3 were performed, and MMPBSA was calculated. Lastly, the ADMET (absorption, distribution, metabolism, excretion, and toxicity) analyses of the novel acridine derivatives were investigated. The tested compounds' existing screening results afford an inspiring basis leading to developing new compelling antimicrobial and anticancer agents based on the acridine scaffold.

2,4-Bis(arylethynyl)-9-chloro-5,6,7,8-tetrahydroacridines: synthesis and photophysical properties

Acridine derivatives have attracted considerable interest in numerous areas owing to their attractive physical and chemical properties. Herein, starting from readily available anthranilic acid, an efficient synthesis of 2,4-bis(arylethynyl)-9-chloro-5,6,7,8-tetrahydroacridine derivatives was accomplished via a one-pot double Sonogashira cross-coupling method. The UV-visible absorption and emission properties of the synthesized molecules have been examined. Additionally, theoretical studies based on density functional theory (DFT/B3LYP/6-31G(d)) were carried out.

Natural DNA Intercalators as Promising Therapeutics for Cancer and Infectious Diseases

Cancer and infectious diseases are one of the greatest challenges of modern medicine. An unhealthy lifestyle, the improper use of drugs, or their abuse are conducive to the increase of morbidity and mortality caused by these diseases. The imperfections of drugs currently used in therapy for these diseases and the increasing problem of drug resistance have forced a search for new substances with therapeutic potential. Throughout history, plants, animals, fungi and microorganisms have been rich sources of biologically active compounds. Even today, despite the development of chemistry and the introduction of many synthetic chemotherapeutics, a substantial part of the new compounds being tested for treatment are still of natural origin. Natural compounds exhibit a great diversity of chemical structures, and thus possess diverse mechanisms of action and molecular targets. Nucleic acids seem to be a good molecular target for substances with anticancer potential in particular, but they may also be a target for antimicrobial compounds. There are many types of interactions of small-molecule ligands with DNA. This publication focuses on the intercalation process. Intercalators are compounds that usually have planar aromatic moieties and can insert themselves between adjacent base pairs in the DNA helix. These types of interactions change the structure of DNA, leading to various types of disorders in the functioning of cells and the cell cycle. This article presents the most promising intercalators of natural origin, which have aroused interest in recent years due to their therapeutic potential.

Acid-promoted synthesis and photophysical properties of substituted acridine derivatives

A simple and efficient synthetic protocol for the preparation of acridinium esters and amides through the cyclization and esterification or amidation of isatins with alcohols or amines as nucleophiles in the presence of CF3SO3H is established. A series of polycyclic acridine derivatives bearing large π-conjugated systems were obtained in high yields, including some key intermediates for the synthesis of biologically active molecules. The photophysical properties of these synthesized acridines were investigated, demonstrating that the sulfur heterocyclic acridine 9w was obtained in a high quantum yield.

Hantzsch-like synthesis of novel bis(hexahydroacridine-1,8-diones), bis(tetrahydrodipyrazolo[3,4-b:4′,3′-e]pyridines), and bis(pyrimido[4,5-b]quinolines) incorporating thieno[2,3-b]thiophenes

A novel series of bis(hexahydroacridine-1,8-diones), bis(tetrahydrodipyrazolo[3,4- b:4′,3′- e]pyridines), and bis(pyrimido[4,5- b]quinolines) incorporating a thieno[2,3- b]thiophene core via ether or ester linkages is prepared via a Hantzsch-like reaction.

New Poly(Propylene Imine) Dendrimer Modified with Acridine and Its Cu(II) Complex: Synthesis, Characterization and Antimicrobial Activity

A second-generation poly(propylene imine) dendrimer modified with acridine and its Cu(II) complex have been synthesized for the first time. It has been found that two copper ions form complexes with the nitrogen atoms of the dendrimeric core by coordinate bonds. The new compounds have been characterized by nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR), fourier-transform infrared spectroscopy (FTIR) and fluorescence spectroscopy. The spectral characteristics of the modified dendrimer have been measured in different organic solvents, and a negative fluorescence solvatochromism has been observed. The antimicrobial activity of the dendrimers has been tested against model pathogenic microorganisms in agar and by broth dilution method. The cotton fabric treated with both dendrimers has been evaluated towards pathogenic microorganisms. The obtained modified cotton fabrics have been shown to hamper bacterial growth and to prevent biofilm formation. Dendrimer cytotoxicity has been investigated in vitro in the model HEp-2 cell line.

To Loop or Not to Loop: Influence of Hinge Flexibility on Self-Assembly Outcomes for Acridine-Based Triazolylpyridine Chelates with Zinc(II), Iron(II), and Copper(II)

Coordination-driven self-assembly has been established as an effective strategy for the efficient construction of intricate architectures in both natural and artificial systems, for applications ranging from gene regulation to metal-organic frameworks. Central to these systems is the need for carefully designed organic ligands, generally with rigid components, that can undergo self-assembly with metal ions in a predictable manner. Herein, we report the synthesis and study of three novel organic ligands that feature 3,6-disubstituted acridine as a rigid spacer connected to two 2-(1,2,3-triazol-4-yl)pyridine "click" chelates through hinges of the same length but differing flexibility. The flexibility of these "three-atom" hinges was modulated by i) moving from secondary to tertiary amide functional groups and ii) replacing an sp² amide carbon with an sp³ methylene carbon. In an effort to understand the role of hinge flexibility in directing self-assembly into mononuclear loops or dinuclear cylinders, the impact of these changes on self-assembly outcomes with zinc(II), iron(II), and copper(II) ions is described.